Ändra sökning
Avgränsa sökresultatet
12 1 - 50 av 74
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Afrasiabi, Roodabeh
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Jokilaakso, Nima
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Schmidt, Torsten
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Björk, P.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Effect of microwave-assisted silanization on sensing properties of silicon nanoribbon FETs2015Ingår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 209, s. 586-595Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An important concern with using silicon nanoribbon field-effect transistors (SiNR FET) for ion-sensing is the pH-response of the gate oxide surface. Depending on the application of the FET sensor, this response has to be chemically manipulated. Thus in silicon oxide-gated pH-sensors with integrated sensor and reference FETS, a surface with high pH-sensitivity, compared to the bare gate oxide, is required in the sensor FETs (SEFET), whereas in the reference FETs (REFET) the surface has to be relatively pH-insensitive. In order to control the sensitivity and chemistry of the oxide surface of the nanoribbons, a silanization reagent with a functional group is often self-assembled on the SiNR surface. Choice of a silanization reaction that results in a self-assembled layer on a silicon oxide surface has been studied extensively over the past decades. However, the effect of various self-assembled layers such as monolayers or mixed layers on the electrical response of SiNR FETs in aqueous solution needs to be exploited further, especially for future integrated SEFET/REFET systems. In this work, we have performed a comprehensive study on 3-aminopropyltriethoxysilane (APTES) silanization of silicon oxide surfaces using microwave (MW) heating as a new biocompatible route to conventional methods. A set of complementary surface characterization techniques (ellipsometry, AFM and ATR-FTIR) was used to analyze the properties of the APTES layer deposited on the silicon surface. We have found that a uniform monolayer can be achieved within 10 min by heating the silanization solution to 75 degrees C using MW heating. Furthermore, electrical measurements suggest that little change in device performance is observed after exposure to MW irradiation. Real-time pH measurements indicate that a uniform APTES monolayer not only reduces the pH sensitivity of SiNR FET by passivating the surface silanol groups, but also makes the device less sensitive to cation concentration in the background electrolyte. Our silanization route proves promising for future chemical surface modification of on-chip REFETs.

  • 2.
    Afrasiabi, Roodabeh
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Jokilaakso, Nima
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Schmidt, Torsten
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Microwave-assisted silanization of SiNW-FET: characterization and effect on sensing propertiesManuskript (preprint) (Övrigt vetenskapligt)
  • 3. Altai, M.
    et al.
    Perols, Anna
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Sandström, M.
    Boschetti, F.
    Orlova, A.
    Tolmachev, V.
    Evaluation of a maleimido derivative of NODAGA for site-specific In-111-labeling of Affibody molecules2011Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 38, s. S146-S146Artikel i tidskrift (Övrigt vetenskapligt)
  • 4. Altai, M.
    et al.
    Strand, J.
    Rosik, Daniel
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Selvaraju, R.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Orlova, A.
    Tolmachev, V.
    Comparative evaluation of anti-HER2 affibody molecules labeled with 68Ga and 111In using maleimido derivatives of DOTA and NODAGA.2012Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 39, s. S299-S299Artikel i tidskrift (Refereegranskat)
  • 5. Altai, M.
    et al.
    Tsourma, M.
    Mitran, B.
    Honarvar, H.
    Perols, Anna
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Robillard, M.
    Rossin, R.
    ten Hoeve, W.
    Sandstrom, M.
    Orlova, A.
    Karlström, Amelie Eriksson
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Tolmachev, V.
    Affibody-based bioorthogonal chemistry-mediated radionuclide pretargeting: proof-of-principle.2015Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 42, s. S246-S246Artikel i tidskrift (Refereegranskat)
  • 6.
    Altai, M.
    et al.
    Immunology, Genetics and Pathology, Uppsala, SWEDEN, .
    Vorobyeva, A.
    Immunology, Genetics and Pathology, Uppsala, SWEDEN, .
    Westerlund, Kristina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Mitran, B.
    Div Mol Imaging, Uppsala, Sweden..
    Orlova, A.
    Div Mol Imaging, Uppsala, Sweden..
    Eriksson Karlström, Amelie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Tolmachev, V.
    Immunology, Genetics and Pathology, Uppsala, SWEDEN, .
    A novel method for conjugation of PNA to antibodies for radionuclide based pretargeting: proof of principal2018Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 45, s. S648-S648Artikel i tidskrift (Övrigt vetenskapligt)
  • 7. Altai, M.
    et al.
    Westerlund, Kristina
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Velletta, J.
    Honarvar, H.
    Orlova, A.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Tolmachev, V.
    Comparative evaluation of Lu-177-HP2 and In-111-HP2, secondary agents for affibody-based PNA-mediated radionuclide pretargeting2016Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 43, s. S237-S237Artikel i tidskrift (Refereegranskat)
  • 8. Altai, M.
    et al.
    Westerlund, Kristina
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Velletta, J.
    Mitran, B.
    Honarvar, H.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Evaluation of affibody molecule-based PNA-mediated radionuclide pretargeting: Development of an optimized conjugation protocol and 177Lu labeling2017Ingår i: Nuclear Medicine and Biology, ISSN 0969-8051, E-ISSN 1872-9614, Vol. 54, s. 1-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction We have previously developed a pretargeting approach for affibody-mediated cancer therapy based on PNA–PNA hybridization. In this article we have further developed this approach by optimizing the production of the primary agent, ZHER2:342-SR-HP1, and labeling the secondary agent, HP2, with the therapeutic radionuclide 177Lu. We also studied the biodistribution profile of 177Lu-HP2 in mice, and evaluated pretargeting with 177Lu-HP2 in vitro and in vivo. Methods The biodistribution profile of 177Lu-HP2 was evaluated in NMRI mice and compared to the previously studied 111In-HP2. Pretargeting using 177Lu-HP2 was studied in vitro using the HER2-expressing cell lines BT‐474 and SKOV-3, and in vivo in mice bearing SKOV-3 xenografts. Results and conclusion Using an optimized production protocol for ZHER2:342-SR-HP1 the ligation time was reduced from 15 h to 30 min, and the yield increased from 45% to 70%. 177Lu-labeled HP2 binds specifically in vitro to BT474 and SKOV-3 cells pre-treated with ZHER2:342-SR-HP1. 177Lu-HP2 was shown to have a more rapid blood clearance compared to 111In-HP2 in NMRI mice, and the measured radioactivity in blood was 0.22 ± 0.1 and 0.68 ± 0.07%ID/g for 177Lu- and 111In-HP2, respectively, at 1 h p.i. In contrast, no significant difference in kidney uptake was observed (4.47 ± 1.17 and 3.94 ± 0.58%ID/g for 177Lu- and 111In-HP2, respectively, at 1 h p.i.). Co-injection with either Gelofusine or lysine significantly reduced the kidney uptake for 177Lu-HP2 (1.0 ± 0.1 and 1.6 ± 0.2, respectively, vs. 2.97 ± 0.87%ID/g in controls at 4 h p.i.). 177Lu-HP2 accumulated in SKOV-3 xenografts in BALB/C nu/nu mice when administered after injection of ZHER2:342-SR-HP1. Without pre-injection of ZHER2:342-SR-HP1, the uptake of 177Lu-HP2 was about 90-fold lower in tumor (0.23 ± 0.08 vs. 20.7 ± 3.5%ID/g). The tumor-to-kidney radioactivity accumulation ratio was almost 5-fold higher in the group of mice pre-injected with ZHER2:342-SR-HP1. In conclusion, 177Lu-HP2 was shown to be a promising secondary agent for affibody-mediated tumor pretargeting in vivo.

  • 9. Altai, Mohamed
    et al.
    Perols, Anna
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Sandström, Mattias
    Boschetti, Frederic
    Orlova, Anna
    Tolmachev, Vladimir
    Preclinical evaluation of anti-HER2 Affibody molecules site-specifically labeled with In-111 using a maleimido derivative of NODAGA2012Ingår i: Nuclear Medicine and Biology, ISSN 0969-8051, E-ISSN 1872-9614, Vol. 39, nr 4, s. 518-529Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction: Affibody molecules have demonstrated potential for radionuclide molecular imaging. The aim of this study was to synthesize and evaluate a maleimido derivative of the 1,4,7-triazacyclononane-l-glutaric acid-4,7-diacetic acid (NODAGA) for site-specific labeling of anti-HER2 Affibody molecule. Methods: The maleimidoethylmonoamide NODAGA (MMA-NODAGA) was synthesized and conjugated to Z(HER2:2395) Affibody molecule having a C-terminal cysteine. Labeling efficiency, binding specificity to and cell internalization by HER2-expressing cells of [In-111-MMA-NODAGA-Cys(61)]-Z(HER2:2395) were studied. Biodistribution of [In-111-MMA-NODAGA-Cys(61)]-Z(HER2:2395) and [In-111-MMA-DOTA-Cys(61)]-Z(HER2:2395) was compared in mice. Results: The affinity of [MMA-NODAGA-Cys(61)]-Z(HER2:2395) binding to HER2 was 67 pM. The In-1111-labeling yield was 99.6%+/- 0.5% after 30 min at 60 degrees C. [In-111-MMA-NODAGA-Cys(61)]-Z(HER2:2395) bound specifically to HER2-expressing cells in vitro and in vivo. Tumor uptake of [In-111-MMA-NODAGA-Cys(61)]-ZHER(2:2395) in mice bearing DU-145 xenografts (4.7%+/- 0.8% ID/g) was lower than uptake of [In-111-MMA-DOTA-Cys(61)]-Z(HER2:2395) (7.5%+/- 1.6% ID/g). However, tumor-to-organ ratios were higher for [In-111-MMA-NODAGA-Cys(61)]-Z(HER2:2395) due to higher clearance rate from normal tissues. Conclusions: MMA-NODAGA is a promising chelator for site-specific labeling of targeting proteins containing unpaired cysteine. Appreciable influence of chelators on targeting properties of Affibody molecules was demonstrated.

  • 10. Altai, Mohamed
    et al.
    Perols, Anna
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Tsourma, Maria
    Mitran, Bogdan
    Honarvar, Hadis
    Robillard, Marc
    Rossin, Raffaella
    ten Hoeve, Wolter
    Lubberink, Mark
    Orlova, Anna
    Karlström, Amelie Eriksson
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Tolmachev, Vladimir
    Feasibility of Affibody-Based Bioorthogonal Chemistry Mediated Radionuclide Pretargeting2016Ingår i: Journal of Nuclear Medicine, ISSN 0161-5505, E-ISSN 1535-5667, Vol. 57, nr 3, s. 431-436Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules constitute a new class of probes for radionuclide tumor targeting. The small size of Affibody molecules is favorable for rapid localization in tumors and clearance from circulation. However, high renal reabsorption of Affibody molecules prevents the use of residualizing radiometals, including several promising low-energy (beta- and alpha-emitters, for radionuclide therapy. We tested a hypothesis that Affibody-based pretargeting mediated by a bioorthogonal interaction between trans-cyclooctene (TCO) and tetrazine would provide higher accumulation of radiometals in tumor xenografts than in the kidneys. Methods: TCO was conjugated to the anti-human epidermal growth factor receptor 2 (HER2) Affibody molecule Z(2395). DOTA-tetrazine was labeled with In-111 and Lu-177. In vitro pretargeting was studied in HER2-expressing SKOV-3 and BT474 cell lines. In vivo studies were performed on BALB/C nu/nu mice bearing SKOV-3 xenografts. Results: I-125-Z(2395)-TCO bound specifically to HER2-expressing cells in vitro with an affinity of 45 +/- 16 pM. In-111-tetrazine bound specifically and selectively to Z(2325)-TCO pretreated cells. In vivo studies demonstrated HER2-specific I-125-Z(2395)-TCO accumulation in xenografts. TCO-mediated In-111-tetrazine localization was shown in tumors, when the radiolabeled tracer was injected 4 h after an injection of Z(2395)-TCO. At 1 h after injection, the tumor uptake of In-111-tetrazine and Lu-177-tetrazine was approximately 2-fold higher than the renal uptake. Pretargeting provided more than a 56-fold reduction of renal uptake of In-111 in comparison with direct targeting. Conclusion: The feasibility of Affibody-based bioorthogonal chemistry-mediated pretargeting was demonstrated. The use of pre-targeting provides a substantial reduction of radiometal accumulation in kidneys, creating preconditions for palliative radionuclide therapy.

  • 11. Altai, Mohamed
    et al.
    Strand, Joanna
    Rosik, Daniel
    Selvaraju, Ram Kumar
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi. KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Orlova, Anna
    Tolmachev, Vladimir
    Influence of Nuclides and Chelators on Imaging Using Affibody Molecules: Comparative Evaluation of Recombinant Affibody Molecules Site-Specifically Labeled with Ga-68 and In-111 via Maleimido Derivatives of DOTA and NODAGA2013Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 24, nr 6, s. 1102-1109Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accurate detection of cancer-associated molecular abnormalities in tumors could make cancer treatment more of personalized. Affibody molecules enable high contrast imaging of tumor-associated protein expression shortly after injection. The use should increase sensitivity of HER2 imaging. The chemical nature of the generator-produced positron-emitting radionuclide Ga-68 of radionuclides and chelators influences the biodistribution of Affibody molecules, providing an opportunity to further increase the imaging contrast. The aim of the study was to compare maleimido derivatives of DOTA and NODAGA for site-specific labeling of a recombinant Z(HER2:2395) HER2-binding Affibody molecule with Ga-68. DOTA and NODAGA were site-specifically conjugated to the Z(HER2:2395) Affibody molecule having a C-terminal cysteine and labeled with Ga-68 and In-111. All labeled conjugates retained specificity to HER2 in vitro. Most of the cell-associated activity was membrane-bound with a minor difference in internalization rate. All variants demonstrated specific targeting of xenografts and a high tumor uptake. The xenografts were dearly visualized using all conjugates. The influence of chelator on the biodistribution and targeting properties was much less pronounced for Ga-68 than for In-111. The tumor uptake of Ga-68-NODAGA-Z(HER2:2395) and Ga-68-NODAGA-Z(HER2:2395) and tumor-to-blood ratios at 2 h p.i. did not differ significantly. However, the tumor-to-liver ratio was significantly higher for Ga-68-NODAGA- Z(HER2:2395) (8 +/- 2 vs 5.0 +/- 0.3) offering the advantage of better liver metastases visualization. In conclusion, influence of chelators on biodistribution of Affibody molecules depends on the radionuclides and reoptimization of labeling chemistry is required when a radionuclide label is changed.

  • 12. Bjorklund, Marcus Gry
    et al.
    Natanaelsson, Christian
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Hao, Yong
    Lundeberg, Joakim
    KTH, Skolan för bioteknologi (BIO), Genteknologi.
    Microarray analysis using disiloxyl 70mer oligonucleotides2008Ingår i: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 36, nr 4, s. 1334-1342Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    DNA microarray technology has evolved dramatically in recent years, and is now a common tool in researchers portfolios. The scope of the technique has expanded from small-scale studies to extensive studies such as classification of disease states. Technical knowledge regarding solid phase microarrays has also increased, and the results acquired today are more reliable than those obtained just a few years ago. Nevertheless, there are various aspects of microarray analysis that could be improved. In this article we show that the proportions of full-length probes used significantly affects the results of global analyses of transcriptomes. In particular, measurements of transcripts in low abundance are more sensitive to truncated probes, which generally increase the degree of cross hybridization and loss of specific signals. In order to improve microarray analysis, we here introduce a disiloxyl purification step, which ensures that all the probes on the microarray are at full length. We demonstrate that when the features on microarrays consist of full-length probes the signal intensity is significantly increased. The overall increase in intensity enables the hybridization stringency to be increased, and thus enhance the robustness of the results.

  • 13.
    Cavallaro, Sara
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Horak, Josef
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Haag, Petra
    Karolinska Inst, Karolinska Univ Hosp, Dept Oncol Pathol, Theme Canc,Patient Area,Pelvis, Akad Straket 1, S-17164 Stockholm, Sweden..
    Gupta, Dhanu
    Karolinska Inst, Clin Res Ctr, Dept Lab Med, S-17177 Stockholm, Sweden.;Evox Therapeut Ltd, Oxford OX4 4HG, England..
    Stiller, Christiane
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Sahu, Siddharth S.
    Uppsala Univ, Angstrom Lab, Dept Solid State Elect, Box 534, SE-75121 Uppsala, Sweden..
    Gorgens, Andre
    Karolinska Inst, Clin Res Ctr, Dept Lab Med, S-17177 Stockholm, Sweden.;Evox Therapeut Ltd, Oxford OX4 4HG, England.;Univ Duisburg Essen, Univ Hosp Essen, Inst Transfus Med, D-45122 Essen, Germany..
    Gatty, Hithesh K.
    Uppsala Univ, Angstrom Lab, Dept Solid State Elect, Box 534, SE-75121 Uppsala, Sweden..
    Viktorsson, Kristina
    Karolinska Inst, Dept Oncol Pathol, Karolinska Univ Hosp, Theme Canc,Patient Area,Head & Neck Lung & Skin, Akad Straket 1, S-17164 Solna, Sweden..
    El Andaloussi, Samir
    Karolinska Inst, Clin Res Ctr, Dept Lab Med, S-17177 Stockholm, Sweden.;Evox Therapeut Ltd, Oxford OX4 4HG, England..
    Lewensohn, Rolf
    Karolinska Inst, Dept Oncol Pathol, Karolinska Univ Hosp, Theme Canc,Patient Area,Head & Neck Lung & Skin, Akad Straket 1, S-17164 Solna, Sweden..
    Eriksson Karlström, Amelie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering. KTH Royal Inst Technol, Sch Engn Sci Chem Biotechnol & Hlth, Dept Prot Sci, AlbalNova Univ Ctr, S-10691 Stockholm, Sweden..
    Linnros, Jan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik. KTH Royal Inst Technol, Sch Engn Sci, Dept Appl Phys, S-16440 Kista, Sweden..
    Dev, Apurba
    Uppsala Univ, Angstrom Lab, Dept Solid State Elect, Box 534, SE-75121 Uppsala, Sweden..
    Label-Free Surface Protein Profiling of Extracellular Vesicles by an Electrokinetic Sensor2019Ingår i: ACS SENSORS, ISSN 2379-3694, Vol. 4, nr 5, s. 1399-1408Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Small extracellular vesicles (sEVs) generated from the endolysosomal system, often referred to as exosomes, have attracted interest as a suitable biomarker for cancer diagnostics, as they carry valuable biological information and reflect their cells of origin. Herein, we propose a simple and inexpensive electrical method for label-free detection and profiling of sEVs in the size range of exosomes. The detection method is based on the electrokinetic principle, where the change in the streaming current is monitored as the surface markers of the sEVs interact with the affinity reagents immobilized on the inner surface of a silica microcapillary. As a proof-of-concept, we detected sEVs derived from the non-small-cell lung cancer (NSCLC) cell line H1975 for a set of representative surface markers, such as epidermal growth factor receptor (EGFR), CD9, and CD63. The detection sensitivity was estimated to be similar to 175000 sEVs, which represents a sensor surface coverage of only 0.04%. We further validated the ability of the sensor to measure the expression level of a membrane protein by using sEVs displaying artificially altered expressions of EGFR and CD63, which were derived from NSCLC and human embryonic kidney (HEK) 293T cells, respectively. The analysis revealed that the changes in EGFR and CD63 expressions in sEVs can be detected with a sensitivity in the order of 10% and 3%, respectively, of their parental cell expressions. The method can be easily parallelized and combined with existing microfluidic-based EV isolation technologies, allowing for rapid detection and monitoring of sEVs for cancer diagnosis.

  • 14. Chen, Si
    et al.
    Jokilaakso, Nima
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Björk, Per
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Zhang, Shi-Li
    A two-terminal silicon nanoribbon field-effect pH sensor2010Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 97, nr 26, s. 264102-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports on a two-terminal silicon nanoribbon (SiNR) field-effect pH sensor operated in electrolyte. Observed experimentally and confirmed by modeling, the sensor is activated by self-gating with a gate bias set by the potential difference of the two terminals. The effect of this gate bias on the SiNR conductance is modulated by the potential drop over the electrical double layer (EDL) established on the SiNR surface, similarly to the threshold voltage modulation by EDL in a three-terminal SiNR field-effect transistor with an independent gate electrode. The potential drop over EDL is determined by the pH value of the electrolyte.

  • 15. Chen, Si
    et al.
    Nyholm, Leif
    Jokilaakso, Nima
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Karlström, Amelie Eriksson
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Smith, Ulf
    Zhang, Shi-Li
    Current Instability for Silicon Nanowire Field-Effect Sensors Operating in Electrolyte with Platinum Gate Electrodes2011Ingår i: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 14, nr 7, s. J34-J37Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Current instability is observed for silicon nanowire field-effect transistors operating in electrolytes with Pt gate electrodes. A comparative study involving an Ag/AgCl-reference gate electrode reveals that the effect results from a drift in the potential at the Pt-electrode/electrolyte interface. In a phosphate buffer saline of pH 7.4, the stabilization of the potential of the Pt electrode was found to require approximately 1000 s. A concurrent potential drift, with a comparable time constant, occurring at the electrolyte/oxidized-nanowire interface rendered a complex device current response which complicated the interpretation of the results.

  • 16.
    Ekblad, Torun
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Orlova, Anna
    Feldwisch, Joachim
    Wennborg, Anders
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Tolmachev, Vladimir
    Positioning of Tc-99m-chelators influences radiolabeling, stability and biodistribution of Affibody molecules2009Ingår i: Bioorganic & Medicinal Chemistry Letters, ISSN 0960-894X, E-ISSN 1090-2120, Vol. 19, nr 14, s. 3912-3914Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules represent a novel class of affinity proteins with a high potential as tracers for radio-nuclide molecular imaging. In this comparative structure-property study, a series of Affibody molecules with the Tc-99m-chelators maGGG, maSSS, or maESE attached to the e-amine of the internally positioned K49 was prepared by peptide synthesis, for comparison to molecules with similar chelators positioned at the N-terminus. The conjugates were labeled with Tc-99m and evaluated in vitro and in vivo. It was found that both composition and position of the chelating moiety influence the label stability, biodistribution and targeting properties of HER2-binding Affibody molecules.

  • 17.
    Ekblad, Torun
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Tolmachev, Vladimir
    Uppsala Univ, Rudbeck Lab, Unit Biomed Radiat Sci.
    Orlova, Anna
    Uppsala Univ, Rudbeck Lab, Unit Biomed Radiat Sci.
    Lendel, Christofer
    Univ Cambridge, Dept Chem.
    Abrahmsén, Lars
    Affibody AB.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Synthesis and chemoselective intramolecular crosslinking of a HER2-binding Affibody2009Ingår i: Biopolymers, ISSN 0006-3525, E-ISSN 1097-0282, Vol. 92, nr 2, s. 116-123Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The human epidermal growth factor receptor HER2 has emerged as an important target for molecular imaging of breast cancer. This article presents the design and synthesis of a HER2-targeting affibody molecule with improved stability and tumor targeting capacity and with potential use as an imaging agent. The 58 aa three-helix bundle protein was assembled using solid-phase peptide synthesis, and a chemoselective ligation strategy was used to establish an intramolecular thioether bond between the side chain thiol group of a cysteine residue, positioned in the loop between helices I and II, and a chloroacetyl group on the side chain amino group of the C-terminal lysine residue. The tethered protein offered an increased thermal stability, with a melting temperature of 64 degrees C, compared to 54 degrees C for the linear control. The ligation did not have a major influence on the HER2 binding affinity, which was 320 and 380 pM for the crosslinked and linear molecules, respectively. Biodistribution studies were performed both in normal and tumor-bearing mice to evaluate the impact of the crosslinking on the in vivo behavior and on the tumor targeting performance. The distribution pattern was characterized by a low uptake in all organs except kidney, and rapid clearance from blood and normal tissue. Crosslinking of the protein resulted in a significantly increased tumor accumulation, rendering the tethered HER2-binding affibody molecule a valuable lead in the development of superior HER2 imaging agents.

  • 18.
    Ekblad, Torun
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Tran, Thuy
    Unit of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    Orlova, Anna
    Unit of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    Widström, Charles
    Section of Hospital Physics, Department of Oncology, Uppsala University Hospital.
    Feldwisch, Joachim
    Unit of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    Abrahmsén, Lars
    Affibody AB, Bromma.
    Wennborg, Anders
    Affibody AB, Bromma.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO).
    Tolmachev, Vladimir
    Unit of Nuclear Medicine, Department of Medical Sciences, Uppsala University.
    Development and preclinical characterisation of 99mTc-labelled Affibody molecules with reduced renal uptake2008Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 35, nr 12, s. 2245-2255Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose  Affibody molecules are low molecular weight proteins (7 kDa), which can be selected to bind to tumour-associated target proteins with subnanomolar affinity. Because of rapid tumour localisation and clearance from nonspecific compartments, Affibody molecules are promising tracers for molecular imaging. Earlier, 99mTc-labelled Affibody molecules demonstrated specific targeting of tumour xenografts. However, the biodistribution was suboptimal either because of hepatobiliary excretion or high renal uptake of the radioactivity. The goal of this study was to optimise the biodistribution of Affibody molecules by chelator engineering. Materials and methods  Anti-HER2 ZHER2:342 Affibody molecules, carrying the mercaptoacetyl-glutamyl-seryl-glutamyl (maESE), mercaptoacetyl-glutamyl-glutamyl-seryl (maEES) and mercaptoacetyl-seryl-glutamyl-glutamyl (maSEE) chelators, were prepared by peptide synthesis and labelled with 99mTc. The tumour-targeting capacity of these conjugates was compared with each other and with the best previously available conjugate, 99mTc-maEEE-ZHER2:342, in nude mice bearing SKOV-3 xenografts. The tumour-targeting capacity of the most promising conjugate, 99mTc-maESE-ZHER2:342, was compared with radioiodinated ZHER2:342. Results  All novel conjugates demonstrated successful tumour targeting and a low degree of hepatobiliary excretion. The renal uptakes of serine-containing conjugates, 33 ± 5, 68 ± 21 and 71 ± 10%IA/g, for99mTc-maESE-ZHER2:342, 99mTc-maEES-ZHER2:342 and 99mTc-maSEE-ZHER2:342, respectively, were significantly reduced in comparison with 99mTc-maEEE-ZHER2:342 (102 ± 13%IA/g). For 99mTc-maESE-ZHER2:342, a tumour uptake of 9.6 ± 1.8%IA/g and a tumour-to-blood ratio of 58 ± 6 were reached at 4 h p.i. Conclusions  A combination of serine and glutamic acid residues in the chelator sequence confers increased renal excretion and relatively low renal uptake of 99mTc-labelled Affibody molecules. In combination with preserved targeting capacity, this improved imaging of targets in abdominal area.

  • 19.
    Elfström, Niklas
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO).
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Silicon Nanoribbons for Electrical Detection of Biomolecules2008Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, nr 3, s. 945-949Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Direct electrical detection of biomolecules at high sensitivity hat recently been demonstrated using semiconductor nanowires. Here we demonstrate that semiconductor nanoribbons, in this case, a thin sheet of silicon on an oxidized silicon substrate, can approach the same sensitivity extending below the picomolar concentration regime in the biotin/streptavidin case. This corresponds to less than similar to 20 analyte molecules bound to receptors on the nanoribbon surface. The micrometer-size lateral dimensions of the nanoribbon enable optical lithography to be used, resulting in a simple and high-yield fabrication process. Electrical characterization of the nanoribbons is complemented by computer simulations showing enhanced sensitivity for thin ribbons. Finally, we demonstrate that the device can be operated both in inversion as well as in accumulation mode and the measured differences in detection sensitivity are explained in terms of the distance between the channel and the receptor coated surface with respect to the Debye screening length. The nanoribbon approach opens up for large scale CMOS fabrication of highly sensitive biomolecule sensor chips for potential use in medicine and biotechnology.

  • 20.
    Elfström, Niklas
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Juhasz, Robert
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Sychugov, Ilya
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Engfeldt, Torun
    KTH, Skolan för bioteknologi (BIO).
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO).
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Surface Charge Sensitivity of Silicon Nanowires: Size Dependence2007Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 7, nr 9, s. 2608-2612Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Silicon nanowires of different widths were fabricated in silicon on insulator (SOI) material using conventional process technology combined with electron-beam lithography. The aim was to analyze the size dependence of the sensitivity of such nanowires for biomolecule detection and for other sensor applications. Results from electrical characterization of the nanowires show a threshold voltage increasing with decreasing width. When immersed in an acidic buffer solution, smaller nanowires exhibit large conductance changes while larger wires remain unaffected. This behavior is also reflected in detected threshold shifts between buffer solutions of different pH, and we find that nanowires of width > 150 nm are virtually insensitive to the buffer pH. The increased sensitivity for smaller sizes is ascribed to the larger surface/volume ratio for smaller wires exposing the channel to a more effective control by the local environment, similar to a surrounded gate transistor structure. Computer simulations confirm this behavior and show that sensing can be extended even down to the single charge level.

  • 21.
    Engfeldt, Torun
    et al.
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Orlova, Anna
    Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    Tran, Thuy
    Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    Bruskin, Alexander
    Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    Widström, Charles
    Department of Hospital Physics, Uppsala University Hospital.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Tolmachev, Vladimir
    Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    Imaging of HER2-expressing tumours using a synthetic Affibody molecule containing the 99mTc-chelating mercaptoacetyl-glycyl-glycyl-glycyl (MAG3) sequence2007Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 34, nr 5, s. 722-733Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose  Expression of human epidermal growth factor receptor type 2 (HER2) in malignant tumours possesses well-documented prognostic and predictive value. Non-invasive imaging of expression can provide valuable diagnostic information, thereby influencing patient management. Previously, we reported a phage display selection of a small (about 7 kDa) protein, the Affibody molecule ZHER2:342, which binds HER2 with subnanomolar affinity, and demonstrated the feasibility of targeting of HER2-expressing xenografts using radioiodinated ZHER2:342. The goal of this study was to develop a method for 99mTc labelling of ZHER2:342 using the MAG3 chelator, which was incorporated into ZHER2:342 using peptide synthesis, and evaluate the targeting properties of the labelled conjugate. Methods  MAG3-ZHER2:342 was assembled using Fmoc/tBu solid phase peptide synthesis. Biochemical characterisation of the agent was performed using RP-HPLC, ESI-MS, biosensor studies and circular dichroism. A procedure for 99mTc labelling in the presence of sodium/potassium tartrate was established. Tumour targeting was evaluated by biodistribution study and gamma camera imaging in xenograft-bearing mice. Biodistribution of 99mTc-MAG3-ZHER2:342 and 125I-para-iodobenzoate -ZHER2:342 was compared 6 h p.i. Results  Synthetic MAG3-ZHER2:342 possessed an affinity of 0.2 nM for HER2 receptors. The peptide was labelled with 99mTc with an efficiency of about 75–80%. Labelled 99mTc-MAG3-ZHER2:342 retained capacity to bind specifically HER2-expressing SKOV-3 cells in vitro. 99mTc-MAG3-ZHER2:342 showed specific tumour targeting with a contrast similar to a radioiodinated analogue in mice bearing LS174T xenografts. Gamma camera imaging demonstrated clear and specific visualisation of HER2 expression. Conclusion  Incorporation of a mercaptoacetyl-containing chelating sequence during chemical synthesis enabled site-specific 99mTc labelling of the ZHER2:342 Affibody molecule with preserved targeting capacity.

  • 22.
    Engfeldt, Torun
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Renberg, Björn
    KTH, Skolan för bioteknologi (BIO).
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO).
    Nygren, Per-Åke
    KTH, Skolan för bioteknologi (BIO).
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO).
    Chemical Synthesis of Triple-Labelled Three-Helix Bundle Binding Proteins for Specific Fluorescent Detection of Unlabelled Protein2005Ingår i: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 6, nr 6, s. 1043-1050Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Site-specifically triple-labelled three-helix bundle affinity proteins (affibody molecules) have been produced by total chemical Synthesis. The 58 aa affinity proteins were assembled on an automated peptide synthesizer, followed by manual on-resin incorporation of three different reporter groups. An orthogonal protection strategy was developed for the site-specific introduction of 5-(2-aminethylamino)-1-nophthalenesulfonic acid (EDANS) and 6(7-nitrobenzofurazon-4-yiamino)-hexanoic acid (NBDX), constituting a donor/acceptor pair for fluorescence resonance energy transfer (FRET), and a biotin moiety, used for surface immobilization. Circular dichroism and biosensor studies of the synthetic proteins and their recombinant counterparts revealed that the synthetic proteins were folded and retained their binding specificities. The biotin-conjugated protein could be immobilized onto a streptavidin surface without loss of activity. The synthetic, doubly fluorescent-labelled affinity proteins were shown to function as fluorescent biosensors in an assay for the specific detection of unlabelled human IgG and IgA.

  • 23.
    Engfeldt, Torun
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Tran, Thuy
    Unit of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    Orlova, Anna
    Unit of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    Widström, Charles
    Section of Hospital Physics, Department of Oncology, Uppsala University Hospital.
    Feldwisch, Joachim
    Unit of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    Abrahmsén, Lars
    Affibody AB, Bromma.
    Wennborg, Anders
    Affibody AB, Bromma.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO).
    Tolmachev, Vladimir
    Unit of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University.
    99mTc-chelator engineering to improve tumour targeting properties of a HER2-specific Affibody molecule2007Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 34, nr 11, s. 1843-1853Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose  Monitoring HER2 expression is crucial for selection of breast cancer patients amenable to HER2-targeting therapy. The Affibody molecule ZHER2:342 binds to HER2 with picomolar affinity and enables specific imaging of HER2 expression. Previously, ZHER2:342 with the additional N-terminal mercaptoacetyl-glycyl-glycyl-glycyl (maGGG) sequence was labelled with 99mTc and demonstrated specific targeting of HER2-expressing xenografts. However, hepatobiliary excretion caused high radioactivity accumulation in the abdomen. We investigated whether the biodistribution of ZHER2:342 can be improved by substituting glycyl residues in the chelating sequence with more hydrophilic seryl residues.

    Methods  The Affibody molecule ZHER2:342, carrying the chelators mercaptoacetyl-glycyl-seryl-glycyl (maGSG), mercaptoacetyl-glycyl-D-seryl-glycyl [maG(D-S)G] and mercaptoacetyl-seryl-seryl-seryl (maSSS), were prepared by peptide synthesis and labelled with 99mTc. The differences in the excretion pathways were evaluated in normal mice. The tumour targeting capacity of 99mTc-maSSS-ZHER2:342 was studied in nude mice bearing SKOV-3 xenografts and compared with the capacity of radioiodinated ZHER2:342.

    Results  A shift towards renal excretion was obtained when glycine was substituted with serine in the chelating sequence. The radioactivity in the gastrointestinal tract was reduced threefold for the maSSS conjugate in comparison with the maGGG conjugate 4 h post injection (p.i.). The tumour uptake of 99mTc-maSSS-ZHER2:342 was 11.5 ± 0.5% IA/g 4 h p.i., and the tumour-to-blood ratio was 76. The pharmacokinetics and uptake characteristics of technetium-labelled ZHER2:342 were better than those of radioiodinated ZHER2:342.

    Conclusion  The introduction of serine residues in the chelator results in better tumour imaging properties of the Affibody molecule ZHER2:342 compared with glycyl-containing chelators and is favourable for imaging of tumours and metastases in the abdominal area.

  • 24.
    Gantelius, Jesper
    et al.
    KTH, Skolan för bioteknologi (BIO), Nanobioteknologi.
    Nystrand, M.
    Harlin, A.
    Elfverson, G.
    Schwenk, Jochen M.
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Uhlén, Mattias
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Eriksson-Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO).
    Andersson-Svahn, Helene
    KTH, Skolan för bioteknologi (BIO), Nanobioteknologi.
    Evaluation of a lateral flow microarray assay systemArtikel i tidskrift (Övrigt vetenskapligt)
  • 25.
    Hober, Sophia
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Konrad, Anna
    Method for labeling of compounds2010Patent (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The present invention relates to site-specific labeling of antibodies or fragments thereof with one or more reporter group(s) in a way that does not affect antigen binding. The method for labeling antibodies and/or fragments thereof, comprises the following steps a) providing an IgG binding protein, which comprises [alpha]-helix structures, with a photoactivatable group and at least one label; b) forming a mixture of said IgG binding protein and the antibodies and/or fragments to be labeled; and c) UV illuminating said mixture for site-specific labeling of said antibodies and/or fragments thereof. The IgG binding protein is preferably the Z domain of Protein A.

  • 26. Honarvar, H.
    et al.
    Muller, C.
    van der Meulen, N.
    Cohrs, S.
    Westerlund, K.
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO).
    Schibli, R.
    Tolmachev, V.
    Development and application of first Sc-44-labeled Affibody molecule2016Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 43, s. S177-S177Artikel i tidskrift (Refereegranskat)
  • 27. Honarvar, H.
    et al.
    Perols, Anna
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Strand, J.
    Selvaraju, R.
    Orlova, A.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Tolmachev, V.
    Influence of DOTA chelator position on biodistribution and targeting properties of 111 In-labelled anti-HER2 affibody molecules2012Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 39, s. S263-S263Artikel i tidskrift (Övrigt vetenskapligt)
  • 28. Honarvar, H.
    et al.
    Strand, J.
    Perols, Anna
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Orlova, A.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Tolmachev, V.
    Influence of DOTA chelator position on biodistribution and targeting properties of 68Ga-labeled synthetic anti-HER2 Affibody molecules. Comparison with 111In-labeled counterparts2013Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 40, s. S245-S246Artikel i tidskrift (Övrigt vetenskapligt)
  • 29. Honarvar, H.
    et al.
    Strand, J.
    Perols, Anna
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Orlova, Anna
    Selvaraju, R. K.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Tolmachev, V.
    Position for site-specific attachment of a DOTA chelator to synthetic affibody molecules has a different influence on the targeting properties of 68Ga-Compared to 111in-labeled conjugates2014Ingår i: Molecular Imaging, ISSN 1535-3508, E-ISSN 1536-0121, Vol. 13, nr 10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules, small (7 kDa) scaffold proteins, are a promising class of probes for radionuclide molecular imaging. Radiolabeling of Affibody molecules with the positron-emitting nuclide 68Ga would permit the use of positron emission tomography (PET), providing better resolution, sensitivity, and quantification accuracy than single-photon emission computed tomography (SPECT). The synthetic anti-HER2 ZHER2:S1 Affibody molecule was conjugated with DOTA at the N-terminus, in the middle of helix 3, or at the Cterminus. The biodistribution of 68Ga-and 111In-labeled Affibody molecules was directly compared in NMRI nu/nu mice bearing SKOV3 xenografts. The position of the chelator strongly influenced the biodistribution of the tracers, and the influence was more pronounced for 68Ga-labeled Affibody molecules than for the 111In-labeled counterparts. The best 68Ga-labeled variant was 68Ga-[DOTA-A1]-ZHER2:S1, which provided a tumor uptake of 13 ± 1 %ID/g and a tumor to blood ratio of 39 ± 12 at 2 hours after injection. 111In-[DOTA-A1]-ZHER2:S1 and 111In-[DOTA-K58]-ZHER2:S1 were equally good at this time point, providing a tumor uptake of 15 to 16 %ID/g and a tumor to blood ratio in the range of 60 to 80. In conclusion, the selection of the best position for a chelator in Affibody molecules can be used for optimization of their imaging properties. This may be important for the development of Affibody-based and other protein-based imaging probes.

  • 30. Honarvar, Hadis
    et al.
    Jokilaakso, Nima
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Andersson, Karl
    Malmberg, Jennie
    Rosik, Daniel
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Orlova, Anna
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Tolmachev, Vladimir
    Järver, Peter
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Evaluation of backbone-cyclized HER2-binding 2-helix Affibody molecule for In Vivo molecular imaging2013Ingår i: Nuclear Medicine and Biology, ISSN 0969-8051, E-ISSN 1872-9614, Vol. 40, nr 3, s. 378-386Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction: Affibody molecules, small scaffold proteins, have demonstrated an appreciable potential as imaging probes. Affibody molecules are composed of three alpha-helices. Helices 1 and 2 are involved in molecular recognition, while helix 3 provides stability. The size of Affibody molecules can be reduced by omitting the third alpha-helix and cross-linking the two remaining, providing a smaller molecule with better extravasation and quicker clearance of unbound tracer. The goal of this study was to develop a novel 2-helix Affibody molecule based on backbone cyclization by native chemical ligation (NCL). Methods: The HER2-targeting NCL-cyclized Affibody molecule Z(HER2:342min) has been designed, synthesized and site-specifically conjugated with a DOTA chelator. DOTA-Z(HER2:342min) was labeled with In-111 and (68) Ga. The binding affinity of DOTA-Z(HER2:342min) was evaluated in vitro. The targeting properties of In-111- and (68) Ga-DOTA-Z(HER2:342min) were evaluated in mice bearing SKOV-3 xenografts and compared with the properties of In-111- and (68) Ga-labeled PEP09239, a DOTA-conjugated 2-helix Affibody analogue cyclized by a homocysteine disulfide bridge. Results: The dissociation constant (K-D) for DOTA-Z(HER2:342min) binding to HER2 was 18 nM according to SPR measurements. DOTA-Z(HER2:342min) was labeled with In-111 and (68) Ga. Both conjugates demonstrated bi-phasic binding kinetics to HER2-expressing cells, with K-D1 in low nanbmolar range. Both variants demonstrated specific uptake in HER2-expressing xenografts. Tumor-to-blood ratios at 2 h p.i. were 6.1 +/- 1.3 for In-111-DOTA-Z(HER2:342min) and 4.6 +/- 0.7 for (68) Ga-DOTA-Z(HER2:342min). However, the uptake of DOTA-Z(HER2:342min) in lung, liver and spleen was appreciably higher than the uptake of PEP09239-based counterparts. Conclusions: Native chemical ligation enables production of a backbone-cyclized HER2-binding 2-helix Affibody molecule (Z(HER2:342min)) with low nanomolar target affinity and specific tumor uptake.

  • 31. Honarvar, Hadis
    et al.
    Muller, Cristina
    Cohrs, Susan
    Haller, Stephanie
    Westerlund, Kristina
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    van der Meulen, Nicholas P.
    Schibli, Roger
    Tolmachev, Vladimir
    Evaluation of the first Sc-44-labeled Affibody molecule for imaging of HER2-expressing tumors2017Ingår i: Nuclear Medicine and Biology, ISSN 0969-8051, E-ISSN 1872-9614, Vol. 45, s. 15-21Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction: Affibody molecules are small (58 amino acids) high-affinity proteins based on a tri-helix nonimmunoglobulin scaffold. A clinical study has demonstrated that PET imaging using Affibody molecules labeled with Ga-68 (T-1/2 = 68 min) can visualize metastases of breast cancer expressing human epidermal growth factor receptor type 2 (HER2) and provide discrimination between tumors with high and low expression level. This may help to identify breast cancer patients benefiting from HER2-targeting therapies. The best discrimination was at 4 h post injection. Due to longer half-life, a positron-emitting radionuclide Sc-44 (T-1/2 = 4.04 h) might be a preferable label for Affibody molecules for imaging at several hours after injection. Methods: A synthetic second-generation anti-HER2 Affibody molecule Z(HER2:2891) was labeled with Sc-44 via a DOTA-chelator conjugated to the N-terminal amino group. Binding specificity, affinity and cellular processing Sc-44-DOTA-Z(HER2:2891) and Ga-68-DOTA-Z(HER2:2891) were compared in vitro using HER2-expressing cells. Biodistribution and imaging properties of Sc-44-DOTA-Z(HER2,2891) and Ga-68-DOTA-Z(HER2:2891) were evaluated in Balb/c nude mice bearing HER2-expression xenografts. Results: The labeling yield of 98 +/- 2% and specific activity of 7.8 GBq/mu mol were obtained. The conjugate demonstrated specific binding to HER2-expressing SKOV3.ip cells in vitro and to SKOV3.ip xenografts in nude mice. The distribution of radioactivity at 3 h post injection was similar for Sc-44-DOTA-Z(HER2:2891) and Ga-68-DOTA-Z(HER2:2891), but the blood clearance of the Sc-44-labeled variant was slower and the tumor-to-blood ratio was reduced (15 +/- 2 for (SC)-S-44-DOTA-Z(HER2:2891) vs 46 +/- 9 for Ga-68-DOTA-Z(HER2.2891)). At 6 h after injection of Sc-44-DOTA-Z(HER2,2891) the tumor uptake was 8 +/- 2% IA/g and the tumor-to-blood ratio was 51 +/- 8. Imaging using small-animal PET/CT demonstrated that (SC)-S-44-DOTA-ZHER2,2891 provides specific and high-contrast imaging of HER2-expressing xenografts. Conclusion: The Sc-44- DOTA-Z(HER2:2891) Affibody molecule is a promising probe for imaging of HER2-expression in malignant tumors.

  • 32. Honarvar, Hadis
    et al.
    Westerlund, Kristina
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Altai, Mohamed
    Sandstrom, Mattias
    Orlova, Anna
    Tolmachev, Vladimir
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Feasibility of Affibody Molecule-Based PNA-Mediated Radionuclide Pretargeting of Malignant Tumors2016Ingår i: Theranostics, ISSN 1838-7640, E-ISSN 1838-7640, Vol. 6, nr 1, s. 93-103Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules are small (7 kDa), non-immunoglobulin scaffold proteins with a potential as targeting agents for radionuclide imaging of cancer. However, high renal re-absorption of Affibody molecules prevents their use for radionuclide therapy with residualizing radiometals. We hypothesized that the use of Affibody-based peptide nucleic acid (PNA)-mediated pretargeting would enable higher accumulation of radiometals in tumors than in kidneys. To test this hypothesis, we designed an Affibody-PNA chimera Z(HER2:342)-SR-HP1 containing a 15-mer HP1 PNA recognition tag and a complementary HP2 hybridization probe permitting labeling with both I-125 and In-111. In-111-Z(HER2:342)-SR-HP1 bound specifically to HER2-expressing BT474 and SKOV-3 cancer cells in vitro, with a K-D of 6+/-2 pM for binding to SKOV-3 cells. Specific high affinity binding of the radiolabeled complementary PNA probe In-111-/I-125-HP2 to Z(HER2:342)-SR-HP1 pre-treated cells was demonstrated. In-111-Z(HER2:342)-SR-HP1 demonstrated specific accumulation in SKOV-3 xenografts in BALB/C nu/nu mice and rapid clearance from blood. Pre-saturation of SKOV-3 with non-labeled anti-HER2 Affibody or the use of HER2-negative Ramos xenografts resulted in significantly lower tumor uptake of In-111-Z(HER2:342)-SR-HP1. The complementary PNA probe In-111/I-125-HP2 accumulated in SKOV-3 xenografts when Z(HER2:342)-SR-HP1 was injected 4 h earlier. The tumor accumulation of In-111/I-125-HP2 was negligible without Z(HER2:342)-SR-HP1 pre-injection. The uptake of In-111-HP2 in SKOV-3 xenografts was 19+/-2 % ID/g at 1 h after injection. The uptake in blood and kidneys was approximately 50- and 2-fold lower, respectively. In conclusion, we have shown that the use of Affibody-based PNA-mediated pretargeting enables specific delivery of radiometals to tumors and provides higher radiometal concentration in tumors than in kidneys.

  • 33.
    Horak, Josef
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Jansson, Ronnie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Dev, Apurba
    Uppsala Univ, Ångström Lab, Solid State Elect, Uppsala Box 534, SE-75121 Uppsala, Sweden..
    Nilebäck, Linnea
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Behnam, Kiarash
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Linnros, Jan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Hedhammar, My
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Eriksson Karlström, Amelie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Recombinant Spider Silk as Mediator for One-Step, Chemical-Free Surface Biofunctionalization2018Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, nr 21, artikel-id 1800206Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A unique strategy for effective, versatile, and facile surface biofunctionalization employing a recombinant spider silk protein genetically functionalized with the antibody-binding Z domain (Z-4RepCT) is reported. It is demonstrated that Z-silk can be applied to a variety of materials and platform designs as a truly one-step and chemical-free surface modification that site specifically captures antibodies while simultaneously reducing nonspecific adsorption. As a model surface, SiO2 is used to optimize and characterize Z-silk performance compared to the Z domain immobilized by a standard silanization method. First, Z-silk adsorption is investigated and verified its biofunctionality in a long-term stability experiment. To assess the binding capacity and protein-protein interaction stability of Z-silk, the coating is used to capture human antibodies in various assay formats. An eightfold higher binding capacity and 40-fold lower detection limit are obtained in the immunofluorescence assay, and the complex stability of captured antibodies is shown to be improved by a factor of 20. Applicability of Z-silk to functionalize microfluidic devices is demonstrated by antibody detection in an electrokinetic microcapillary biosensor. To test Z-silk for biomarker applications, real-time detection and quantification of human immunoglobulin G are performed in a plasma sample and C1q capture from human serum using an anti-C1q antibody.

  • 34.
    Jokilaakso, Nima
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Afrasiabi, Roodabeh
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Larsson, Andréas
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Björk, Per
    ACREO Swedish ICT.
    Schönberg, Tommy
    ACREO Swedish ICT.
    Linnros, Jan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Spot-on functionalization of SiO2 for multiplexed silicon nanowire-FET biosensorsManuskript (preprint) (Övrigt vetenskapligt)
  • 35.
    Jokilaakso, Nima
    et al.
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Salm, Eric
    Chen, Aaron
    Millet, Larry
    Guevara, Carlos Duarte
    Dorvel, Brian
    Reddy, Bobby, Jr.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Chen, Yu
    Ji, Hongmiao
    Sooryakumar, Ratnasingham
    Bashir, Rashid
    Ultra-localized single cell electroporation using silicon nanowires2013Ingår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 13, nr 3, s. 336-339Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Analysis of cell-to-cell variation can further the understanding of intracellular processes and the role of individual cell function within a larger cell population. The ability to precisely lyse single cells can be used to release cellular components to resolve cellular heterogeneity that might be obscured when whole populations are examined. We report a method to position and lyse individual cells on silicon nanowire and nanoribbon biological field effect transistors. In this study, HT-29 cancer cells were positioned on top of transistors by manipulating magnetic beads using external magnetic fields. Ultra-rapid cell lysis was subsequently performed by applying 600-900 mV(pp) at 10 MHz for as little as 2 ms across the transistor channel and the bulk substrate. We show that the fringing electric field at the device surface disrupts the cell membrane, leading to lysis from irreversible electroporation. This methodology allows rapid and simple single cell lysis and analysis with potential applications in medical diagnostics, proteome analysis and developmental biology studies.

  • 36.
    Järver, P. J.
    et al.
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Mikaelsson, Christoffer
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Abrahmsen, L.
    Affibody AB, Stockholm, Sweden..
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO).
    Synthesis and Biophysical Characterization of a Backbone-Cyclized Minimized Z Domain2010Ingår i: Journal of Peptide Science, ISSN 1075-2617, E-ISSN 1099-1387, Vol. 16, s. 62-62Artikel i tidskrift (Övrigt vetenskapligt)
  • 37.
    Järver, Peter
    et al.
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Mikaelsson, Cecilia
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Karlstrom Eriksson, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Chemical synthesis and evaluation of a backbone-cyclized minimized 2-helix Z-domain2011Ingår i: Journal of Peptide Science, ISSN 1075-2617, E-ISSN 1099-1387, Vol. 17, nr 6, s. 463-469Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Z-molecule is a small, engineered IgG-binding affinity protein derived from the immunoglobulin-binding domain B of Staphylococcus aureus protein A. The Z-domain consists of 58 amino acids forming a well-defined antiparallel three-helix structure. Two of the three helices are involved in ligand binding, whereas the third helix provides structural support to the three-helix bundle. The small size and the stable three-helix structure are two attractive properties comprised in the Z-domain, but a further reduction in size of the protein is valuable for several reasons. Reduction in size facilitates synthetic production of any protein-based molecule, which is beneficial from an economical viewpoint. In addition, a smaller protein is easier to manipulate through chemical modifications. By omitting the third stabilizing helix from the Z-domain and joining the N- and C-termini by a native peptide bond, the affinity protein obtains the advantageous properties of a smaller scaffold and in addition becomes resistant to exoproteases. We here demonstrate the synthesis and evaluation of a novel cyclic two-helix Z-domain. The molecule has retained affinity for its target protein, is resistant to heat treatment, and lacks both N- and C-termini. Copyright (C) 2011 European Peptide Society and John Wiley & Sons, Ltd.

  • 38.
    Konrad, Anna
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Anfelt, Josefin
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Andersson, Sandra
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Hober, Sophia
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Optimization of an antibody labeling strategy through the use of photoactivable synthetic Z domainsManuskript (preprint) (Övrigt vetenskapligt)
  • 39.
    Konrad, Anna
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Hober, Sophia
    KTH, Skolan för bioteknologi (BIO), Proteomik.
    Covalent Immunoglobulin Labeling through a Photoactivable Synthetic Z Domain2011Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 22, nr 12, s. 2395-2403Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditionally, labeling of antibodies has been performed by covalent conjugation to amine or carboxyl groups. These methods are efficient but suffer from nonspecificity, since all free and available amine/carboxyl groups have the possibility to react. This drawback may lead to uncontrolled levels and locations of the labeling. Hence, the labeled molecules might behave differently and, possibly, the binding site of the antibody will also be affected. In this project, we have developed a highly stringent method for labeling of antibodies by utilizing an immunoglobulin-binding domain from protein A, the Z domain. Domain Z has been synthesized with an amino acid analogue, benzoylphenylalanine, capable of forming covalent attachment to other amino acids upon UV-exposure. This feature has been used for directed labeling of immunoglobulins and subsequent use of these in different assays.

  • 40.
    Lindgren, Joel
    et al.
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Ekblad, Caroline
    Abrahmsén, Lars
    Karlström, Amelie Eriksson
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    A Native Chemical Ligation Approach for Combinatorial Assembly of Affibody Molecules2012Ingår i: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 13, nr 7, s. 1024-1031Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affinity molecules labeled with different reporter groups, such as fluorophores or radionuclides, are valuable research tools used in a variety of applications. One class of engineered affinity proteins is Affibody molecules, which are small (6.5 kDa) proteins that can be produced by solid phase peptide synthesis (SPPS), thereby allowing site-specific incorporation of reporter groups during synthesis. The Affibody molecules are triple-helix proteins composed of a variable part, which gives the protein its binding specificity, and a constant part, which is identical for all Affibody molecules. In the present study, native chemical ligation (NCL) has been applied for combinatorial assembly of Affibody molecules from peptide fragments produced by Fmoc SPPS. The concept is demonstrated for the synthesis of three different Affibody molecules. The cysteine residue introduced at the site of ligation can be used for directed immobilization and does not interfere with the function of the investigated proteins. This strategy combines a high-yield production method with facilitated preparation of proteins with different C-terminal modifications.

  • 41.
    Lindgren, Joel
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Intramolecular thioether cross-linking of therapeutic proteins to increase proteolytic stability2014Ingår i: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 15, nr 14, s. 2132-2138Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Protein-based pharmaceuticals typically display high selectivity and low toxicity, but are also characterized by low oral availability, mainly because of enzymatic degradation in the gastrointestinal tract and poor permeability across the intestinal wall. One way to increase the proteolytic stability of peptides and proteins is by intramolecular crosslinking, such as the introduction of disulfide bridges. However, disulfide bridges are at risk of thiol-disulfide exchange or reduction during production, purification, and/or therapeutic use, whereas thioether bridges are expected to be stable under the same conditions. In this study, thioether crosslinking was investigated for a 46 aa albumin-binding domain (ABD) derived from streptococcal protein G. ABD binds with high affinity to human serum albumin (HSA) and has been proposed as a fusion partner to increase the in vivo half-lives of therapeutic proteins. In the study, five ABD variants with single or double intramolecular thioether bridges were designed and synthesized. The binding affinity, secondary structure, and thermal stability of each protein was investigated by SPR-based biosensor analysis and CD spectroscopy. The proteolytic stability in the presence of the major intestinal proteases pepsin (found in the stomach) and trypsin in combination with chymotrypsin (found in pancreatin secreted to the duodenum by the pancreas) was also investigated. The most promising crosslinked variant, ABD_CL1, showed high thermal stability, retained high affinity in binding to HSA, and showed dramatically increased stability in the presence of pepsin and trypsin/chymotrypsin, compared to the ABD reference protein. This suggests that the intramolecular thioether crosslinking strategy can be used to increase the stability towards gastrointestinal enzymes.

  • 42.
    Lindgren, Joel
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Intramolecular Thioether Crosslinking To Increase The Protease Stability Of Small Therapeutic Proteins2014Ingår i: Journal of Peptide Science, ISSN 1075-2617, E-ISSN 1099-1387, Vol. 20, s. S224-S225Artikel i tidskrift (Övrigt vetenskapligt)
  • 43.
    Lindgren, Joel
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Refai, Essam
    Zaitsev, Sergei
    Abrahmsén, Lars
    Berggren, Per-Olof
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    A GLP-1 receptor agonist conjugated to an albumin-binding domain for extended half-life2014Ingår i: Biopolymers, ISSN 0006-3525, E-ISSN 1097-0282, Vol. 102, nr 3, s. 252-259Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Glucagon-like peptide 1 (GLP-1) and related peptide agonists have been extensively investigated for glycaemic control in Type 2 diabetes, and may also have therapeutic applications for other diseases. Due to the short half-life (t1/2<2 min) of the endogenous peptide, caused by proteolytic degradation and renal clearance, different strategies for half-life extension and sustained release have been explored. In the present study, conjugates between a GLP-1 analogue and a 5 kDa albumin-binding domain (ABD) derived from streptococcal protein G have been chemically synthesized and evaluated. ABD binds with high affinity to human serum albumin, which is highly abundant in plasma and functions as a drug carrier in the circulation. Three different GLP-1-ABD conjugates, with the two peptides connected by linkers of two, four, and six PEG units, respectively, were synthesized and tested in mouse pancreatic islets at high (11 mM) and low (3 mM) glucose concentration. Insulin release upon stimulation was shown to be glucose-dependent, showing no significant difference between the three different GLP-1-ABD conjugates and unconjugated GLP-1 analogue. The biological activity, in combination with the high affinity binding to albumin, make the GLP-1-ABD conjugates promising GLP-1 receptor agonists expected to show extended in vivo half-life.

  • 44.
    Lindgren, Joel
    et al.
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Segerfeldt, Patrik
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Sholts, Sabrina B.
    Gräslund, Astrid
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Wärmländer, Sebastian K. T. S.
    Engineered non-fluorescent Affibody molecules facilitate studies of the amyloid-beta (A beta) peptide in monomeric form: Low pH was found to reduce A beta/Cu(II) binding affinity2013Ingår i: Journal of Inorganic Biochemistry, ISSN 0162-0134, E-ISSN 1873-3344, Vol. 120, s. 18-23Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aggregation of amyloid-beta (A beta) peptides into oligomers and amyloid plaques in the human brain is considered a causative factor in Alzheimer's disease (AD). As metal ions are over-represented in AD patient brains, and as distinct A beta aggregation pathways in presence of Cu(II) have been demonstrated, metal binding to A beta likely affects AD progression. A beta aggregation is moreover pH-dependent, and AD appears to involve inflammatory conditions leading to physiological acidosis. Although metal binding specificity to A beta varies at different pH's, metal binding affinity to A beta has so far not been quantitatively investigated at sub-neutral pH levels. This may be explained by the difficulties involved in studying monomeric peptide properties under aggregation-promoting conditions. We have recently devised a modified Affibody molecule, Z(A beta 3)(12-58), that binds A beta with sub-nanomolar affinity, thereby locking the peptide in monomeric form without affecting the N-terminal region where metal ions bind. Here, we introduce non-fluorescent A beta-binding Affibody variants that keep A beta monomeric while only slightly affecting the A beta peptide's metal binding properties. Using fluorescence spectroscopy, we demonstrate that Cu(II)/A beta(1-40) binding is almost two orders of magnitude weaker at pH 5.0 (apparent K-D = 51 mu M) than at pH 7.3 (apparent K-D = 0.86 mu M). This effect is arguably caused by protonation of the histidines involved in the metal ligandation. Our results indicate that engineered variants of Affibody molecules are useful for studying metal-binding and other properties of monomeric A beta under various physiological conditions, which will improve our understanding of the molecular mechanisms involved in AD.

  • 45.
    Lindgren, Joel
    et al.
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101). KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Wahlstrom, Anna
    Danielsson, Jens
    Markova, Natalia
    Ekblad, Caroline
    Graslund, Astrid
    Abrahmsen, Lars
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101). KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Warmlander, Sebastian K. T. S.
    N-terminal engineering of amyloid-beta-binding Affibody molecules yields improved chemical synthesis and higher binding affinity2010Ingår i: Protein Science, ISSN 0961-8368, E-ISSN 1469-896X, Vol. 19, nr 12, s. 2319-2329Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aggregation of amyloid-beta (A beta) peptides is believed to be a major factor in the onset and progression of Alzheimer's disease Molecules binding with high affinity and selectivity to A beta-peptides are important tools for investigating the aggregation process An A beta-binding Affibody molecule, Z(A beta 3), has earlier been selected by phage display and shown to bind A beta(1-40) with nanomolar affinity and to inhibit A beta-peptide aggregation In this study, we create truncated functional versions of the Z(A beta 3) Affibody molecule better suited for chemical synthesis production Engineered Affibody molecules of different length were produced by solid phase peptide synthesis and allowed to form covalently linked homodimers by S-S-bridges The N-terminally truncated Affibody molecules Z(A beta 3)(12-58), Z(A beta 3)(15-58), and Z(A beta 3)(18-58) were produced in considerably higher synthetic yield than the corresponding full-length molecule Z(A beta 3)(1-58) Circular dichroism spectroscopy and surface plasmon resonance-based biosensor analysis showed that the shortest Affibody molecule, Z(A beta 3)(18-58), exhibited complete loss of binding to the A beta(1-40)-peptide, while the Z(A beta 3)(12-58) and Z(A beta 3)(15-58) Affibody molecules both displayed approximately one order of magnitude higher binding affinity to the A beta(1-40)-peptide compared to the full-length Affibody molecule Nuclear magnetic resonance spectroscopy showed that the structure of A beta(1-40) in complex with the truncated Affibody dimers is very similar to the previously published solution structure of the A beta(1-40)-peptide in complex with the full-length Z(A beta 3) Affibody molecule This indicates that the N-terminally truncated Affibody molecules Z(A beta 3)(12-58) and Z(A beta 3)(15-58) are highly promising for further engineering and future use as binding agents to monomeric A beta(1-40)

  • 46. Malmberg, Jennie
    et al.
    Perols, Anna
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Varasteh, Zohreh
    Altai, Mohamed
    Braun, Alexis
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Sandström, Mattias
    Garske, Ulrike
    Tolmachev, Vladimir
    Orlova, Anna
    Karlström, Amelie Eriksson
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Comparative evaluation of synthetic anti-HER2 Affibody molecules site-specifically labelled with In-111 using N-terminal DOTA, NOTA and NODAGA chelators in mice bearing prostate cancer xenografts2012Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 39, nr 3, s. 481-492Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose In disseminated prostate cancer, expression of human epidermal growth factor receptor type 2 (HER2) is one of the pathways to androgen independence. Radionuclide molecular imaging of HER2 expression in disseminated prostate cancer might identify patients for HER2-targeted therapy. Affibody molecules are small (7 kDa) targeting proteins with high potential as tracers for radionuclide imaging. The goal of this study was to develop an optimal Affibody-based tracer for visualization of HER2 expression in prostate cancer. Methods A synthetic variant of the anti-HER2 Z(HER2:342) Affibody molecule, Z(HER2:S1), was N-terminally conjugated with the chelators DOTA, NOTA and NODAGA. The conjugated proteins were biophysically characterized by electrospray ionization mass spectroscopy (ESI-MS), circular dichroism (CD) spectroscopy and surface plasmon resonance (SPR)-based biosensor analysis. After labelling with In-111, the biodistribution was assessed in normal mice and the two most promising conjugates were further evaluated for tumour targeting in mice bearing DU-145 prostate cancer xenografts. Results The HER2-binding equilibrium dissociation constants were 130, 140 and 90 pM for DOTA-Z(HER2:S1), NOTA-Z(HER2:S1) and NODAGA-Z(HER2:S1), respectively. A comparative study of In-111-labelled DOTA-Z(HER2:S1), NOTA-Z(HER2:S1) and NODAGA-Z(HER2:S1) in normal mice demonstrated a substantial influence of the chelators on the biodistribution properties of the conjugates. In-111-NODAGA-Z(HER2:S1) had the most rapid clearance from blood and healthy tissues. In-111-NOTA-Z(HER2:S1) showed high hepatic uptake and was excluded from further evaluation. In-111-DOTA-Z(HER2:S1) and In-111-NODAGAZHER2: S1 demonstrated specific uptake in DU-145 prostate cancer xenografts in nude mice. The tumour uptake of In-111-NODAGA-Z(HER2:S1), 5.6 +/- 0.4% ID/g, was significantly lower than the uptake of In-111-DOTA-Z(HER2:S1), 7.4 +/- 0.5% ID/g, presumably because of lower bioavailability due to more rapid clearance. In-111-NODAGA-Z(HER2:S1) provided higher tumour-to-blood ratio, but somewhat lower tumour-to-liver, tumour-to-spleen and tumour-to-bone ratios. Conclusion Since distant prostate cancer metastases are situated in bone or bone marrow, the higher tumour-to-bone ratio is the most important. This renders In-111-DOTA-Z(HER2:S1) a preferable agent for imaging of HER2 expression in disseminated prostate cancer.

  • 47.
    Nilsson, Anders
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Lindgren, Joel
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Intramolecular Thioether Crosslinking to Increase the Proteolytic Stability of Affibody Molecules2017Ingår i: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 18, nr 20, s. 2056-2062Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Protein therapeutics suffer from low oral bioavailability, mainly due to poor membrane permeability and digestion by gastrointestinal proteases. To improve proteolytic stability, intramolecular thioether crosslinks were introduced into a three-helix affibody molecule binding the human epidermal growth factor receptor (EGFR). Solid-phase peptide synthesis was used to produce an unmodified control protein domain and three different crosslinked protein domain variants: one with a thioether crosslink between the N-terminal lysine residue and a cysteine residue in the second loop region (denoted K4), a second with a crosslink between the C-terminal lysine residue and a cysteine residue in the first loop region (denoted K58), and a third with crosslinks in both positions (denoted K4K58). Circular dichroism (CD) and surface-plasmon-resonance-based (SPR-based) biosensor studies of the protein domains showed that the three-helix structure and high-affinity binding to EGFR were preserved in the crosslinked protein domains. In vitro digestion by gastrointestinal proteases demonstrated that the crosslinked protein domains showed increased stability towards pepsin and towards a combination of trypsin and chymotrypsin.

  • 48. Orlova, Anna
    et al.
    Tran, Thuy A.
    Ekblad, Torun
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Tolmachev, Vladimir
    Re-186-maSGS-Z(HER2:342), a potential Affibody conjugate for systemic therapy of HER2-expressing tumours2010Ingår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 37, nr 2, s. 260-269Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules are a novel class of tumour-targeting proteins, which combine small size (7 kDa) and picomolar affinities. The Affibody molecule Z(HER2:342) has been suggested for imaging of HER2 expression in order to select patients for trastuzumab therapy. When optimizing chelators for Tc-99m-labelling, we have found that synthetic Z(HER2:342) conjugated with mercaptoacetyl-glycyl-glycyl-glycyl (maGGG) and mercaptoacetyl-glycyl-seryl-glycyl (maGSG) chelators provides relatively low renal uptake of radioactivity and could be suitable for therapy. maGGG-Z(HER2:342) and maGSG-Z(HER2:342) were labelled with Re-186 and their biodistribution was studied in normal mice. Dosimetric evaluation and tumour targeting to HER2-overexpressed xenografts (SKOV-3) by Re-186-maGSG-Z(HER2:342) were studied. Gluconate-mediated labelling of maGGG-Z(HER2:342) and maGSG-Z(HER2:342) with Re-186 provided a yield of more than 95% within 60 min. The conjugates were stable and demonstrated specific binding to HER2-expressing SKOV-3 cells. Biodistribution in normal mice demonstrated rapid blood clearance, low accumulation of radioactivity in the kidney and other organs, accumulating free perrhenate. Both Re-186-maGGG-Z(HER2:342) and Re-186-maGSG-Z(HER2:342) demonstrated lower renal uptake than their Tc-99m-labelled counterparts. Re-186-maGSG-Z(HER2:342) provided the lowest uptake in healthy tissues. Biodistribution of Re-186-maGSG-Z(HER2:342) in nude mice bearing SKOV-3 xenografts showed specific targeting of tumours. Tumour uptake 24 h after injection (5.84 +/- 0.54%ID/g) exceeded the concentration in blood by more than 500-fold, and uptake in kidneys by about 8-fold. Preliminary dosimetric evaluation showed that dose-to-tumour should exceed dose-to-kidney by approximately 5-fold. Optimization of chelators improves biodistribution properties of rhenium-labelled small scaffold proteins and enables selection of promising radiotherapeutic agents based on the Affibody molecule.

  • 49. Orlova, Anna
    et al.
    Tran, Thuy
    Widström, Charles
    Engfeldt, Torun
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi (stängd 20130101).
    Tolmachev, Vladimir
    Pre-clinical evaluation of -benzyl-DOTA-ZHER2: 3429 a potential agent for imaging of HER2 expression in malignant tumors2007Ingår i: International Journal of Molecular Medicine, ISSN 1107-3756, E-ISSN 1791-244X, Vol. 20, nr 3, s. 397-404Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Imaging of expression of human epidermal growth factor receptor type 2 (HER2) in breast carcinomas may help to select patients eligible for trastuzumab therapy. The Affibody molecule Z(HER2:342) is a small (7-kDa) non-immunoglobulin affinity protein, which binds to HER2 with a picomolar affinity. Previously, a benzyl-DTPA conjugate of Z(HER2:342) was labeled with In-111 and demonstrated good targeting in murine xenografts. We considered that the use of the macrocyclic chelator DOTA could increase the label stability and enhance a choice of nuclides, which could be used as a label for Z(HIR2:342). The goal of this study was the preparation and pre-clinical evaluation of the indium- 111 labeled DOTA-derivative of Z(HER2:342)- Isothiocyanate-benzyl-DOTA was coupled to recombinant Z(HER2:342), and the conjugate was efficiently labeled with In-111 at 60 degrees C. The specificity of In-111-benzyl-DOTA-Z(HER2:342) binding to HER2 was confirmed in vitro using HER2-expressing breast carcinoma BT474 and ovarian carcinoma SKOV-3 cell lines. Biodistribution of In-111-benzyl-DOTA-Z(HER2:342) was performed in nude mice bearinLy LS174T xenografts and compared directly with the biodistribution of In-111-benzyl-DTPA-Z(HR2:342). In vivo, In-111-benzyl-DOTA-Z(HER2:312) demonstrated quick clearance from blood and non-specific organs except the kidneys. Four hours post injection (pi), the tumor uptake of In-111-benzyl-DOTA-Z(HER2:342) (4.4 +/- 1.0% IA/g) was specific and the tumor-to-blood ratio was 23. The use of benzyl-DTPA provided higher tumor-to-blood and tumor-to-liver ratios. gamma-camera imaging showed clear visualization of HER2-expressing xenografts using In-111-benzyl-DOTA-Z(HER2:342). In-111-benzyl-DOTA-Z(HER2:342) has a potential for imaging of HER2 expression in malignant tumors.

  • 50.
    Perols, Anna
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Arcos Famme, Melina
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Eriksson Karlström, Amelie
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Site-specific antibody labeling by covalent photoconjugation of Z domains functionalized for alkyne-azide cycloaddition reactions2015Ingår i: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 16, nr 17, s. 2522-2529Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Antibodies are extensively used both as research tools and in the clinics for diagnostics and therapy. For many applications the antibodies are labeled, e.g. with detection probes or cytotoxic agents that improve the therapeutic effect. Labeling is typically performed using amine-reactive probes targeting lysine residues accessible on the surface of the protein, resulting in a heterogeneously labeled antibody. One alternative strategy for site-specific labeling is to use the immunoglobulin G (IgG)-binding protein domain Z, which binds to the Fc-region of IgG. By introducing the photoactivable amino acid benzoylphenylalanine (BPA) in the Z domain, a covalent bond can be formed between the Z domain and the antibody by UV irradiation, to produce a site-specifically labeled product. The Z domain with BPA in position 32,  Z32BPA, was synthesized by solid phase peptide synthesis and was further functionalized for alkyne-azide cycloaddition reactions to give alkyne-Z32BPA and azide-Z32BPA for Cu(I)-catalyzed click reaction, and DBCO-Z32BPA for Cu-free strain-promoted click reaction. The reactivity of the functionalized Z domains in Cu(I)-catalyzed and strain-promoted alkyne-azide cycloaddition reactions was analyzed using MALDI-TOF MS and RP-HPLC, showing fast reaction. To further evaluate the concept, the Z32BPA variants were conjugated to the human IgG1 antibody trastuzumab and biotinylated by Cu(I)-catalyzed or strain-promoted alkyne-azide cycloaddition reactions. Western blot analysis of the biotinylated antibodies, using streptavidin-HRP for detection, demonstrated that all Z-antibody conjugates could be site-specifically labeled by the alkyne-azide cycloaddition reactions.

12 1 - 50 av 74
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf