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Publications (10 of 144) Show all publications
Cavallaro, S., Horak, J., Haag, P., Gupta, D., Stiller, C., Sahu, S. S., . . . Dev, A. (2019). Label-Free Surface Protein Profiling of Extracellular Vesicles by an Electrokinetic Sensor. ACS SENSORS, 4(5), 1399-1408
Open this publication in new window or tab >>Label-Free Surface Protein Profiling of Extracellular Vesicles by an Electrokinetic Sensor
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2019 (English)In: ACS SENSORS, ISSN 2379-3694, Vol. 4, no 5, p. 1399-1408Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
Keywords
extracellular vesicles, electrokinetic effect, biosensor, label-free, protein profiling, cancer
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:kth:diva-254037 (URN)10.1021/acssensors.9b00418 (DOI)000469410100034 ()31020844 (PubMedID)2-s2.0-85066017871 (Scopus ID)
Note

Qc 20190814

Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-08-14Bibliographically approved
Sychugov, I., Zhang, M. & Linnros, J. (2019). Non-stationary analysis of molecule capture and translocation in nanopore arrays. Journal of Chemical Physics, 150(8), Article ID 084904.
Open this publication in new window or tab >>Non-stationary analysis of molecule capture and translocation in nanopore arrays
2019 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 150, no 8, article id 084904Article in journal (Refereed) Published
Abstract [en]

Analytical formulas for the ON- and OFF-time distributions as well as for the autocorrelation function were derived for the case of single molecule translocation through nanopore arrays. The obtained time-dependent expressions describe very well experimentally recorded statistics of DNA translocations through an array of solid state nanopores, which allows us to extract molecule and system related physical parameters from the experimental traces. The necessity of non-stationary analysis as opposite to the steady-state approximation has been vindicated for the molecule capture process, where different time-dependent regimes were identified. A long tail in the distribution of translocation times has been rationalized invoking Markov jumps, where a possible sequential ordering of events was elucidated through autocorrelation function analysis. Published under license by AIP Publishing.

Place, publisher, year, edition, pages
AMER INST PHYSICS, 2019
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-247835 (URN)10.1063/1.5060661 (DOI)000460034700030 ()30823763 (PubMedID)2-s2.0-85062398572 (Scopus ID)
Note

QC 20190326

Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2019-04-04Bibliographically approved
Liu, L., Deng, L., Huang, S., Zhang, P., Linnros, J., Zhong, H. & Sychugov, I. (2019). Photodegradation of Organometal Hybrid Perovskite Nanocrystals: Clarifying the Role of Oxygen by Single-Dot Photoluminescence. Journal of Physical Chemistry Letters, 10(4), 864-869
Open this publication in new window or tab >>Photodegradation of Organometal Hybrid Perovskite Nanocrystals: Clarifying the Role of Oxygen by Single-Dot Photoluminescence
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2019 (English)In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 10, no 4, p. 864-869Article in journal (Refereed) Published
Abstract [en]

Photostability has been a major issue for perovskite materials. Understanding the photodegradation mechanism and suppressing it are of central importance for applications. By investigating single-dot photoluminescence spectra and the lifetime of MAPbX(3) (MA = CH3NH3+, X = Br, I) nanocrystals with quantum confinement under different conditions, we identified two separate pathways in the photodegradation process. The first is the oxygen-assisted light-induced etching process (photochemistry). The second is the light-driven slow charge-trapping process (photophysics), taking place even in oxygen-free environment. We clarified the role of oxygen in the photodegradation process and show how the photoinduced etching can be successfully suppressed by OSTE polymer, preventing an oxygen-assisted reaction.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-246263 (URN)10.1021/acs.jpclett.9b00143 (DOI)000459948800026 ()30730749 (PubMedID)2-s2.0-85061915174 (Scopus ID)
Note

QC 20190327

Available from: 2019-03-27 Created: 2019-03-27 Last updated: 2019-04-04Bibliographically approved
Marinins, A., Udalcovs, A., Ozolins, O., Pang, X., Veinot, J., Jacobsen, G., . . . Popov, S. (2018). All-optical intensity modulation in polymer waveguides doped with si quantum dots. In: Optics InfoBase Conference Papers: . Paper presented at CLEO: Applications and Technology, CLEO_AT 2018, 13 May 2018 through 18 May 2018. Optical Society of America
Open this publication in new window or tab >>All-optical intensity modulation in polymer waveguides doped with si quantum dots
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2018 (English)In: Optics InfoBase Conference Papers, Optical Society of America, 2018Conference paper, Published paper (Refereed)
Abstract [en]

We demonstrate all-optical intensity modulation in integrated PMMA optical waveguides doped with silicon quantum dots. The 1550 nm probe signal is absorbed by free carriers excited in silicon quantum dots with 405 nm pump light.

Place, publisher, year, edition, pages
Optical Society of America, 2018
Keywords
Fiber optic sensors, Light modulation, Nanocrystals, Semiconductor quantum dots, Waveguides, 1550 nm, All optical, Free carriers, Polymer waveguides, Probe signals, Pump light, Si quantum dot, Silicon quantum dots, Optical signal processing
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-236442 (URN)10.1364/CLEO_AT.2018.JW2A.31 (DOI)2-s2.0-85049142554 (Scopus ID)9781557528209 (ISBN)
Conference
CLEO: Applications and Technology, CLEO_AT 2018, 13 May 2018 through 18 May 2018
Note

QC 20181025

Available from: 2018-10-25 Created: 2018-10-25 Last updated: 2018-10-25Bibliographically approved
Parmeggiani, M., Dev, A., Björk, P. & Linnros, J. (2018). Electrokinetic-assisted gating in a microfluidic integrated Si nanoribbon ion sensor for enhanced sensitivity. Sensors and actuators. B, Chemical, 262, 974-981
Open this publication in new window or tab >>Electrokinetic-assisted gating in a microfluidic integrated Si nanoribbon ion sensor for enhanced sensitivity
2018 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 262, p. 974-981Article in journal (Refereed) Published
Abstract [en]

Using the electrokinetic principle, we demonstrate a novel approach to modulate the response of an ion sensitive silicon-nanoribbon field-effect-transistor, effectively manipulating the device sensitivity to a change in surface potential. By using the streaming potential effect we show that the changes in the surface potential induced by e.g. a pH change can be accurately manipulated in a microfluidic-integrated chip leading to an enhanced response. By varying the flow velocity and the biasing condition along the microfluidic channel, we further demonstrate that the pH response from such a device can also be suppressed or even reversed as a function of the flow velocity and the biasing configuration. Experiments performed with different pH buffer shows that the sensor response can be enhanced/suppressed by several times in magnitude simply by using the streaming potential effects. A mathematical description is also presented for qualitative assessment of the electrokinetic influence on the gate terminal under different biasing condition. The approach presented here shows the prospect to exploit the electrokinetic modulation for developing highly sensitive nanoscale biosensors. © 2018 Elsevier B.V.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Electrokinetic effect, Ion sensitive field-effect transistor, Microfluidics, pH sensing, Silicon nanoribbon, Streaming potential
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-227556 (URN)10.1016/j.snb.2018.02.017 (DOI)000427460600116 ()2-s2.0-85042270625 (Scopus ID)
Funder
Swedish Research Council, 2016-05051Knut and Alice Wallenberg Foundation, 2011.0113
Note

QC 20180517

Available from: 2018-05-17 Created: 2018-05-17 Last updated: 2018-05-17Bibliographically approved
Chulapakorn, T., Sychugov, I., Ottosson, M., Primetzhofer, D., Moro, M. V., Linnros, J. & Hallén, A. (2018). Luminescence of silicon nanoparticles from oxygen implanted silicon. Materials Science in Semiconductor Processing, 86, 18-22
Open this publication in new window or tab >>Luminescence of silicon nanoparticles from oxygen implanted silicon
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2018 (English)In: Materials Science in Semiconductor Processing, ISSN 1369-8001, E-ISSN 1873-4081, Vol. 86, p. 18-22Article in journal (Refereed) Published
Abstract [en]

Oxygen with a kinetic energy of 20 keV is implanted in a silicon wafer (100) at different fluences, followed by post-implantation thermal annealing (PIA) performed at temperatures ranging from 1000 to 1200 degrees C, in order to form luminescent silicon nanoparticles (SiNPs) and also to reduce the damage induced by the implantation. As a result of this procedure, a surface SiOx layer (with 0 < x < 2) with embedded crystalline Si nanoparticles has been created. The samples yield similar luminescence in terms of peak wavelength, lifetime, and absorption as recorded from SiNPs obtained by the more conventional method of implanting silicon into silicon dioxide. The oxygen implantation profile is characterized by elastic recoil detection (ERD) technique to obtain the excess concentration of Si in a presumed SiO2 environment. The physical structure of the implanted Si wafer is examined by grazing incidence X-ray diffraction (GIXRD). Photoluminescence (PL) techniques, including PL spectroscopy, time-resolved PL (TRPL), and photoluminescence excitation (PLE) spectroscopy are carried out in order to identify the PL origin. The results show that luminescent SiNPs are formed in a Si sample implanted by oxygen with a fluence of 2 x 10(17) atoms cm(-2) and PIA at 1000 degrees C. These SiNPs have a broad size range of 6-24 nm, as evaluated from the GIXRD result. Samples implanted at a lower fluence and/or annealed at higher temperature show only weak defect-related PL. With further optimization of the SiNP luminescence, the method may offer a simple route for integration of luminescent Si in mainstream semiconductor fabrication.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Oxygen implantation, Silicon nanoparticles, Photoluminescence
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-232741 (URN)10.1016/j.mssp.2018.06.004 (DOI)000439119400003 ()2-s2.0-85048803830 (Scopus ID)
Funder
Swedish Foundation for Strategic Research , RIF14-0053Swedish Research Council, 821-2012-5144 2017-00646_9 821-2012-5144 2017-00646_9
Note

QC 20180803

Available from: 2018-08-03 Created: 2018-08-03 Last updated: 2018-08-06Bibliographically approved
Pevere, F., Sangghaleh, F., Bruhn, B., Sychugov, I. & Linnros, J. (2018). Rapid Trapping as the Origin of Nonradiative Recombination in Semiconductor Nanocrystals. ACS Photonics, 5(8), 2990-2996
Open this publication in new window or tab >>Rapid Trapping as the Origin of Nonradiative Recombination in Semiconductor Nanocrystals
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2018 (English)In: ACS Photonics, E-ISSN 2330-4022, Vol. 5, no 8, p. 2990-2996Article in journal (Refereed) Published
Abstract [en]

We demonstrate that nonradiative recombination in semiconductor nanocrystals can be described by a rapid luminescence intermittency, based on carrier tunneling to resonant traps. Such process, we call it "rapid trapping (blinking)", leads to delayed luminescence and promotes Auger recombination, thus lowering the quantum efficiency. To prove our model, we probed oxide- (containing static traps) and ligand- (trap-free) passivated silicon nanocrystals emitting at similar energies and featuring monoexponential blinking statistics. This allowed us to find analytical formulas and to extract characteristic trapping/detrapping rates, and quantum efficiency as a function of temperature and excitation power. Experimental single-dot temperature-dependent decays, supporting the presence of one or few resonant static traps, and ensemble saturation curves were found to be very well described by this effect. The model can be generalized to other semiconductor nanocrystals, although the exact interplay of trapping/detrapping, radiative, and Auger processes may be different, considering the typical times of the processes involved.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
quantum dots, photoluminescence, blinking, efficiency, Auger recombination
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-234625 (URN)10.1021/acsphotonics.8b00581 (DOI)000442185900004 ()2-s2.0-85050020891 (Scopus ID)
Funder
Swedish Research Council
Note

QC 20180913

Available from: 2018-09-13 Created: 2018-09-13 Last updated: 2019-08-20Bibliographically approved
Horak, J., Jansson, R., Dev, A., Nilebäck, L., Behnam, K., Linnros, J., . . . Eriksson Karlström, A. (2018). Recombinant Spider Silk as Mediator for One-Step, Chemical-Free Surface Biofunctionalization. Advanced Functional Materials, 28(21), Article ID 1800206.
Open this publication in new window or tab >>Recombinant Spider Silk as Mediator for One-Step, Chemical-Free Surface Biofunctionalization
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2018 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, no 21, article id 1800206Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2018
Keywords
biomarker, biosensing, C1q, surface biofunctionalization, Z-silk
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:kth:diva-231216 (URN)10.1002/adfm.201800206 (DOI)000434030500011 ()2-s2.0-85047860287 (Scopus ID)
Note

QC 20180628

Available from: 2018-06-28 Created: 2018-06-28 Last updated: 2018-11-23Bibliographically approved
Zhang, M., Ngampeerapong, C., Redin, D., Ahmadian, A., Sychugov, I. & Linnros, J. (2018). Thermophoresis-Controlled Size-Dependent DNA Translocation through an Array of Nanopores. ACS Nano, 12(5), 4574-4582
Open this publication in new window or tab >>Thermophoresis-Controlled Size-Dependent DNA Translocation through an Array of Nanopores
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2018 (English)In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 5, p. 4574-4582Article in journal (Refereed) Published
Abstract [en]

Large arrays of nanopores can be used for high-throughput biomolecule translocation with applications toward size discrimination and sorting at the single-molecule level. In this paper, we propose to discriminate DNA length by the capture rate of the molecules to an array of relatively large nanopores (50–130 nm) by introducing a thermal gradient by laser illumination in front of the pores balancing the force from an external electric field. Nanopore arrays defined by photolithography were batch processed using standard silicon technology in combination with electrochemical etching. Parallel translocation of single, fluorophore-labeled dsDNA strands is recorded by imaging the array with a fast CMOS camera. The experimental data show that the capture rates of DNA molecules decrease with increasing DNA length due to the thermophoretic effect of the molecules. It is shown that the translocation can be completely turned off for the longer molecule using an appropriate bias, thus allowing a size discrimination of the DNA translocation through the nanopores. A derived analytical model correctly predicts the observed capture rate. Our results demonstrate that by combining a thermal and a potential gradient at the nanopores, such large nanopore arrays can potentially be used as a low-cost, high-throughput platform for molecule sensing and sorting.

Keywords
array; capture rate; electrochemical etching; nanopore; silicon; sorting; thermophoresis
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-228463 (URN)10.1021/acsnano.8b00961 (DOI)000433404500054 ()2-s2.0-85047380512 (Scopus ID)
Note

QC 20180525

Available from: 2018-05-24 Created: 2018-05-24 Last updated: 2018-06-19Bibliographically approved
Pevere, F., von Treskow, C., Marino, E., Anwar, M., Bruhn, B., Sychugov, I. & Linnros, J. (2018). X-ray radiation hardness and influence on blinking in Si and CdSe quantum dots. Applied Physics Letters, 113(25), Article ID 253103.
Open this publication in new window or tab >>X-ray radiation hardness and influence on blinking in Si and CdSe quantum dots
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2018 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 113, no 25, article id 253103Article in journal (Refereed) Published
Abstract [en]

We study the effect of X-ray irradiation on the photoluminescence (PL) efficiency and intermittency (blinking) of single Si/SiO2 and CdSe/CdZnS quantum dots (QDs). Our results show that the PL efficiency of Si nanocrystals is not significantly altered up to a cumulative fluence of 10(20) photons/m(2) (corresponding to similar to 300 kGy of absorbed dose in SiO2), while CdSe particles become completely dark already after a 17 times lower fluence. In both types of QDs, the statistical nature of blinking ON- and OFF-times remains unaltered: mono-exponential for Si and power-law for CdSe QDs. However, the evolution of the blinking parameters with absorbed dose depends on the choice of material. On average, both ON- and OFF-time constants do not vary in Si nanocrystals, highlighting their radiation hardness. Instead, the ON-time exponent increases while the OFF-time exponent decreases with the increasing dose for CdSe dots, confirming their efficiency quenching. Ensemble measurements did not show PL spectral changes neither indicated removal of surface ligands in irradiated CdSe dots. Thus, ionization-generated non-radiative centers in the core-shell system modify blinking of CdSe dots and eventually rapidly quench their emission, in contrast to robust Si/SiO2 nanocrystals. Our study is important for the future use of luminescent QDs in harsh environments, such as space, and the engineering of their blinking properties via ionizing radiation.

National Category
Condensed Matter Physics
Research subject
Physics
Identifiers
urn:nbn:se:kth:diva-238792 (URN)10.1063/1.5053885 (DOI)000454216900019 ()2-s2.0-85058886377 (Scopus ID)
Funder
Swedish Research Council, VR 2015-0464
Note

Credit for the Accepted Manuscript: AIP Publishing

Reference: Federico Pevere, Carl von Treskow, Emanuele Marino, Monib Anwar, Benjamin Bruhn, Ilya Sychugov and Jan Linnros, "X-ray radiation hardness and influence on blinking in Si and CdSe quantum dots," Applied Physics Letters, Volume 113, Issue 25, pp. 25310, Year 2018.

QC 20190115

Available from: 2018-11-11 Created: 2018-11-11 Last updated: 2019-04-24Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5260-5322

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