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Optical monitoring of single nanoparticle capture in solid-state nanopore array
- 2019
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Proceedings (redaktörskap) (refereegranskat)abstract
- Solid-state nanopore arrays hold promises for high-throughput optical or electrical analysis of nanoscale entities. Here, we demonstrate an optical monitoring system for investigation of the capture process of single nanoparticles driven by electrophoretic force in a nanopore array. Over 50% of the single nanoparticle capture events are achieved by controlling the applied voltage across the nanopore membrane with a tailored nanopore size. We find that at a certain voltage bias, the capture of single nanoparticles is a self-termination process.
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Parallelized single-molecule translocations in arrayed silicon nanopores coated with a lipid bilayer
- 2019
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Proceedings (redaktörskap) (refereegranskat)abstract
- Solid-state nanopores have been recognized as a versatile tool for single-molecule detection with high sensitivity. They have been extensively studied for analysis by nanopore translocation of biomolecules, such as DNA, RNA, and proteins. As a complement to the electrical sensing readout, optical sensing of labeled molecules on a solid-state nanopore array can notably enhance the sensing capacity with high throughput. However, the widely used silicon nitride (SiNx) nanopore produces significant photoluminescence (PL) background under blue-green laser illumination, which can severely limit, e.g., multicolor sensing for DNA barcode discrimination. In addition, the occasionally occurring irreversible DNA clogging in a solid-state nanopore, because of DNA molecules interacting with the nanopore channel wall during translocation, can seriously affect the sensing efficacy and accuracy. To address these problems, we have developed an optical sensing system dedicated to nanopore arrays fabricated in a free-standing silicon membrane with its surface functionalized by lipid bilayer coating.A silicon nanopore array with pores of sub-20 nm diameter is fabricated in a silicon-on-insulator wafer using electron beam lithography in combination with anisotropic etching. The 55 nm thick free-standing silicon membrane shows negligible PL emission in the 550 to 800 nm spectral range under blue-green laser illumination, which greatly improves the optical signal-to-background ratio for single-molecule detection in comparison with standard SiNx devices. The formation of a lipid bilayer on the nanopore walls is successful as inferred by monitoring in situ the stepwise reduction of the nanopore conductance of ionic current and subsequently by observing ex situ the homogenous fluorescence emitted from a labeled lipid bilayer. As a demonstration, we perform the optical sensing measurements with a conventional wide-field microscope to detect the translocation of fluorophore-labeled DNA strands (120 kbp). With the low background PL of the silicon membrane, the optical signal of individual DNA translocation events is more clearly identified than when using similarly processed SiNx nanopore devices. Moreover, the coated fluidic lipid bilayer provides a nonstick surface to minimize the non-specific interaction of DNA molecules with the silicon pore walls. The results show that the DNA clogging is substantially reduced in the lipid bilayer coated nanopores as compared to uncoated nanopores. These results demonstrate that using silicon nanopores coated by a lipid bilayer is a promising strategy to realizing massively-parallel single-molecule optical detection.
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Conceptual Modeling : Proceedings
- 2015
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Proceedings (redaktörskap) (refereegranskat)abstract
- This book constitutes the refereed proceedings of the 34th International Conference on Conceptual Modeling, ER 2015, held in Stockholm, Sweden, in October 2015. The 26 full and 19 short papers presented were carefully reviewed and selected from 131 submissions. The papers are organized in topical sections on business process and goal models, ontology-based models and ontology patterns, constraints, normalization, interoperability and integration, collaborative modeling, variability and uncertainty modeling, modeling and visualization of user generated content, schema discovery and evolution, process and text mining, domain-based modeling, data models and semantics, and applications of conceptual modeling.
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Proceedings from the Tenth International Symposium on Tunnel Safety and Security
- 2023
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Proceedings (redaktörskap) (refereegranskat)abstract
- This publication includes the Proceedings of the 10th International Symposium on Tunnel Safety and Security (ISTSS) held in Stavanger, Norway, April 26-28, 2023. The Proceedings include 45 papers and 16 posters. The papers were presented in 16 different sessions, i.e., Keynote sessions, Alternative Fuel Vehicle Safety, Risk Management & Explosion, Digitization, Explosion, Poster Corner, Ventilation 1&2, Fixed Fire Fighting Systems, Tenability and Evacuation, Emergency Management, Evacuation, Safety Management, Fire Dynamics and Resistance. Each day was opened by invited Keynote Speakers (in total five) addressing broad topics of pressing interest. The Keynote Speakers, selected as leaders in their field, consisted of Ove Njå (University of Stavanger, Norway), Vladimir Molkov (Ulster University, UK), Ulf Lundström (Swedish Transport Administration, Sweden), Mirjam Nelisse (TNO, The Netherlands), and Gunnar Jenssen (SINTEF, Norway). We are grateful that the keynote speakers were able to share their knowledge and expertise with the participants of the symposium.
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