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Jussi, Johnny Israelsson
Publications (3 of 3) Show all publications
Karlsson, M., Strandqvist, C., Jussi, J. I., Oberg, O., Petermann, I., Elmlund, L., . . . Wang, Q. (2019). Chemical Sensors Generated on Wafer-Scale Epitaxial Graphene for Application to Front-Line Drug Detection. Sensors, 19(10), Article ID 2214.
Open this publication in new window or tab >>Chemical Sensors Generated on Wafer-Scale Epitaxial Graphene for Application to Front-Line Drug Detection
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2019 (English)In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 10, article id 2214Article in journal (Refereed) Published
Abstract [en]

Generation of large areas of graphene possessing high quality and uniformity will be a critical factor if graphene-based devices/sensors are to be commercialized. In this work, epitaxial graphene on a 2" SiC wafer was used to fabricate sensors for the detection of illicit drugs (amphetamine or cocaine). The main target application is on-site forensic detection where there is a high demand for reliable and cost-efficient tools. The sensors were designed and processed with specially configured metal electrodes on the graphene surface by utilizing a series of anchors where the metal contacts are directly connected on the SiC substrate. This has been shown to improve adhesion of the electrodes and decrease the contact resistance. A microfluidic system was constructed to pump solutions over the defined graphene surface that could then act as a sensor area and react with the target drugs. Several prototypic systems were tested where non-covalent interactions were used to localize the sensing components (antibodies) within the measurement cell. The serendipitous discovery of a wavelength-dependent photoactivity for amphetamine and a range of its chemical analogs, however, limited the general application of these prototypic systems. The experimental results reveal that the drug molecules interact with the graphene in a molecule dependent manner based upon a balance of -stacking interaction of the phenyl ring with graphene (p-doping) and the donation of the amine nitrogens lone pair electrons into the *-system of graphene (n-doping).

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
epitaxial graphene, sensors, microfluidics, photoactivity, illicit drugs, forensics
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-255223 (URN)10.3390/s19102214 (DOI)000471014500001 ()31091664 (PubMedID)2-s2.0-85066874691 (Scopus ID)
Note

QC 20190903

Available from: 2019-09-03 Created: 2019-09-03 Last updated: 2019-09-03Bibliographically approved
Fu, Y., Jussi, J. I., Elmlund, L., Dunne, S., Wang, Q. & Brismar, H. (2019). Intrinsic blinking characteristics of single colloidal CdSe-CdS/ZnS core-multishell quantum dots. Physical Review B, 99(3), Article ID 035404.
Open this publication in new window or tab >>Intrinsic blinking characteristics of single colloidal CdSe-CdS/ZnS core-multishell quantum dots
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2019 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, no 3, article id 035404Article in journal (Refereed) Published
Abstract [en]

Fluorescence blinking of single colloidal semiconductor quantum dots (QDs) has been extensively studied, and several sophisticated models have been proposed. In this work, we derive Heisenberg equations of motion to carefully study principal transition processes, i.e., photoexcitation, energy relaxation, impact ionization and Auger recombination, radiative and nonradiative recombinations, and tunneling between core states and surface states, of the electron-hole pair in single CdSe-CdS/ZnS core-multishell QDs and show that the on-state probability density distribution of the QD fluorescence obeys the random telegraph signal theory because of the random radiative recombination of the photoexcited electron-hole pair in the QD core, while the off-state probability density distribution obeys the inverse power law distribution due to the series of random walks of the photoexcited electron in the two-dimensional surface-state network after the electron tunnels from the QD core to the QD surface. These two different blinking characteristics of the single QD are resolved experimentally by properly adjusting the optical excitation power and the bin time.

Place, publisher, year, edition, pages
AMER PHYSICAL SOC, 2019
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-241317 (URN)10.1103/PhysRevB.99.035404 (DOI)000454766400012 ()2-s2.0-85059881217 (Scopus ID)
Note

QC 20190125

Available from: 2019-01-25 Created: 2019-01-25 Last updated: 2019-01-25Bibliographically approved
Yin, H., Fontana, J. M., Solandt, J., Jussi, J. I., Xu, H., Brismar, H. & Fu, Y. (2017). Quantum dots modulate intracellular Ca2+ level in lung epithelial cells. International Journal of Nanomedicine, 12, 2781-2792
Open this publication in new window or tab >>Quantum dots modulate intracellular Ca2+ level in lung epithelial cells
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2017 (English)In: International Journal of Nanomedicine, ISSN 1176-9114, E-ISSN 1178-2013, Vol. 12, p. 2781-2792Article in journal (Refereed) Published
Abstract [en]

While adverse effects of nanoparticles on lung health have previously been proposed, few studies have addressed the direct effects of nanoparticle exposure on the airway epithelium. In this work, we examine the response of the pulmonary airway to nanoparticles by measuring intracellular Ca2+ concentration ([Ca2+](i)) in the Calu-3 epithelial layer stimulated by 3-mercaptopropionic-acid (3MPA) coated CdSe-CdS/ZnS core-multishell quantum dots (QDs). Simultaneous transient transepithelial electrical resistance (TEER) decrease and global [Ca2+](i) increase in Calu-3 epithelial layer, accompanied by cell displacements, contraction, and expansion, were observed under QD deposition. This suggests that a QD-induced global [Ca2+](i) increase in the Calu-3 epithelial layer caused the transient TEER decrease. The [Ca2+](i) increase was marked and rapid in the apical region, while [Ca2+](i) decreased in the basolateral region of the epithelial layer. TEER transient response and extracellular Ca2+ entry induced by QD deposition were completely inhibited in cells treated with stretched-activated (SA) inhibitor GdCl3 and store-operated calcium entry (SOCE) inhibitor BTP2 and in cells immersed in Ca2+-free medium. The voltage-gated calcium channel (VGCC) inhibitor nifedipine decreased, stabilized, and suppressed the TEER response, but did not affect the [Ca2+](i) increase, due to QD deposition. This demonstrates that the Ca2+ influx activated by QDs' mechanical stretch occurs through activation of both SA and SOCE channels. QD-induced [Ca2+](i) increase occurred in the Calu-3 epithelial layer after culturing for 15 days, while significant TEER drop only occurred after 23 days. This work provides a new perspective from which to study direct interactions between airway epithelium and nanoparticles and may help to reveal the pathologies of pulmonary disease.

Place, publisher, year, edition, pages
DOVE MEDICAL PRESS LTD, 2017
Keywords
Calu-3 epithelial layer, quantum dot, intracellular Ca2+ concentration [Ca2+](i), transepithelial electrical resistance, cell movement
National Category
Nano Technology Pharmaceutical Sciences
Identifiers
urn:nbn:se:kth:diva-206308 (URN)10.2147/IJN.S130136 (DOI)000398663200001 ()2-s2.0-85017256402 (Scopus ID)
Note

QC 20170505

Available from: 2017-05-05 Created: 2017-05-05 Last updated: 2018-01-13Bibliographically approved
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