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Karlsson, M., Strandqvist, C., Jussi, J., Öberg, 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 π -stacking interaction of the phenyl ring with graphene (p-doping) and the donation of the amine nitrogens lone pair electrons into the π - π *-system of graphene (n-doping).

Place, publisher, year, edition, pages
NLM (Medline), 2019
Keywords
epitaxial graphene, forensics, illicit drugs, microfluidics, photoactivity, sensors
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-39057 (URN)10.3390/s19102214 (DOI)2-s2.0-85066874691 (Scopus ID)
Available from: 2019-06-26 Created: 2019-06-26 Last updated: 2019-06-26Bibliographically approved
Fu, Y., Jussi, J., Wang, Q., Brismar, H., Liu, Y., Yang, X. & Chen, Y. (2019). Endocytic pathway of vascular cell adhesion molecule 1 in human umbilical vein endothelial cell identified in vitro by using functionalized nontoxic fluorescent quantum dots. Sensors and actuators. B, Chemical, 297, Article ID 126702.
Open this publication in new window or tab >>Endocytic pathway of vascular cell adhesion molecule 1 in human umbilical vein endothelial cell identified in vitro by using functionalized nontoxic fluorescent quantum dots
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2019 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 297, article id 126702Article in journal (Refereed) Published
Abstract [en]

Studies about vascular cell adhesion molecule 1 (VCAM1) in tumor growth, metastasis, and angiogenesis suggest that targeting VCAM1 expression is an attractive strategy for diagnosis and anti-tumor therapy. However, the endocytic pathway of VCAM1 in vascular cells has not been well characterized. In this study we visualize the endocytic pathway of tumor necrosis factor α (TNFα) induced VCAM1 in human umbilical vein endothelial cell (HUVEC) in vitro using 5-carboxyfluorescein labeled VCAM1 binding peptides and fluorescent water-dispersible 3-mercaptopropionic acid (3MPA)-coated CdSe-CdS/Cd0.5Zn0.5S/ZnS core–multishell nontoxic quantum dots (3MPA-QDs) functionalized with VCAM1 binding peptides. Clear key in vitro observations are as follows: (a) 3MPA-QDs functionalized with VCAM1 binding peptides, denoted as VQDs, adhered and aggregated cumulatively to cell membrane around 2 h after VQD deposition to cell culture medium and were found in lysosomes in TNFα-treated HUVECs approximately 24 h after VQD deposition; (b) VQDs remained in TNFα-treated HUVECs for the whole 16 days of the experimental observation period; (c) quite differently, 3MPA-QDs were endocytosed then exocytosed by HUVECs via endosomes in about 24–48 h after 3MPA-QD deposition. Our study suggests that VCAM1 molecules, initially expressed on cell membrane induced by TNFα treatment, are internalized into lysosomes. This provides a novel means to deliver materials to lysosomes such as enzyme replacement therapy. Moreover, our meticulous sensing methodology of devising fluorescent nontoxic QDs advances biosensing technique for studying cellular activities in vitro and in vivo. © 2019 The Authors

Place, publisher, year, edition, pages
Elsevier B.V., 2019
Keywords
Bionanosensors, Colloidal fluorescent quantum dot, Endosome, Human umbilical vein endothelial cell, Lysosome, Vascular cell adhesion molecule 1 (VCAM1)
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-39425 (URN)10.1016/j.snb.2019.126702 (DOI)2-s2.0-85067809943 (Scopus ID)
Note

 Funding details: Stiftelsen för Strategisk Forskning, Forskningsinstitutsdoktorand 2015; Funding details: National Natural Science Foundation of China, 61674022; Funding details: National Natural Science Foundation of China; Funding text 1: The work was partially supported by the Swedish Foundation for Strategic Research (Forskningsinstitutsdoktorand 2015), the National Natural Science Foundation of China (NSFC) (Grant No. 61674022 ), and Changshu Mingwei Medical Technology Co., Ltd. (Changshu, China). Appendix A; Funding text 2: The following are the supplementary data to this article: Ying Fu is an associate professor at the Royal Institute of Technology, focusing on research and technological development of fluorescent quantum dot biomarkers to study cellular biophysics and molecular events of clinical relevance. Johnny Jussi completed a Master of Science and Engineering at the Royal Institute of Technology in 2016. He is now studying a PhD on developing tool kits for on-site forensic analysis of bio samples. Qin Wang , senior expert at Research Institutes of Sweden (RISE), received her Ph.D. degree in solid state physics at Lund University in Sweden, in 1999. Her research fields at Lund focused on electron transport physics in nanoelectronic devices based on quantum dots and quantum wires. Since 2000 she has been working at RISE Acreo in design, fabrication and characterization of nano/micro sensors/devices and related monolithic or hybrid sensor system integrations. She is the author or co-author of more than 100 international journal, conference and workshop papers. She is one of selected experts to review proposals for different calls from European Commission. She a board Member of IEEE Photonics Sweden, also a member of Electrum Laboratory strategy group at Royal Technology Institute (KTH). She is supervisor for Master and PhD degree students. Hjalmar Brismar is professor of Biological Physics at KTH – the Royal Institute of Technology in Stockholm, Sweden. He obtained the PhD degree in physics at KTH in 1996 and then did postdoctoral training in the Biomedical Imaging Laboratory at Harvard School of Public Health, Boston. In 1997 he was appointed assistant professor at Karolinska Institutet and was promoted to associate professor in experimental pediatrics in 2001. In 2003 he accepted the position as full professor in Biological Physics at KTH. Since 2013 he is also director for the national infrastructure in microscopy at Science for Life Laboratory. His research interest is in membrane protein biophysics and development of biophysical measurement technology, in particular advanced light microscopy. Xifeng Yang , professor at Changshu institute of technology, obtained her PHD in Microelectronics and solid state electronics from the Shanghai institute of technology and physics (China) in 2009. In 2009, she came to Changshu institute of technology. She was sponsored by the Chinese State Foundation for Studying Abroad to visit the Royal Institute of Technology (Sweden) during 2012 and 2013 as a “Senior Visiting Scholar”. She mainly focuses on the photoelectric and thermoelectric properties of nanomaterials. As the first author or corresponding author, she have published more than 30 papers. Yushen Liu is a professor at Changshu institute of technology. He received the PhD degree in Physics from the Fudan University (China) in 2007. In 2008, he came to the Changshu institute of technology as a lecturer. In 2010, he applied for a fellowship to the Indian State University. One year later, he came back the Changshu institute of technology. He has published over 50 papers in refereed journals. Currently, he is vice dean of school of physics and Electronic Engineering. Yun Chen completed her PhD at University of Link”oping, Sweden in 1996. She has been focusing on molecular mechanisms of cardiovascular diseases and has years of research experience in biochemical analysis and data analysis. She was the project leader for project “Molecular imaging of early atherogenesis using quantum nanoparticles” supported by Swedish VINNOVA. In recent years, she has been focusing on identifying early molecular changes associated with psychosocial stress in adolescents.

Available from: 2019-07-08 Created: 2019-07-08 Last updated: 2019-07-08Bibliographically approved
Fu, Y., Jussi, J., 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.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-37334 (URN)10.1103/PhysRevB.99.035404 (DOI)2-s2.0-85059881217 (Scopus ID)
Available from: 2019-01-22 Created: 2019-01-22 Last updated: 2019-06-27Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3606-8985

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