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Full-Text Articles in Nanoscience and Nanotechnology

Microbiorobots For Single Cell Manipulation, Mahmut Selman Sakar Nov 2010

Microbiorobots For Single Cell Manipulation, Mahmut Selman Sakar

Publicly Accessible Penn Dissertations

One of the great challenges in nano and micro scale science and engineering is the independent manipulation of biological cells and small man-made objects with active sensing. For such biomedical applications as single cell manipulation, telemetry, and localized targeted delivery of chemicals, it is important to fabricate microstructures that can be powered and controlled without a tether in fluidic environments. These microstructures can be used to develop microrobots that have the potential to make existing therapeutic and diagnostic procedures less invasive.

Actuation can be realized using various different organic and inorganic methods. Previous studies explored different forms of actuation and ...


Second-Harmonic Imaging Microscopy Of Living Cells, Paul J. Campagnola, Heather Clark, William A. Mohler, Aaron Lewis (Prof.), Leslie M. Loew Nov 2010

Second-Harmonic Imaging Microscopy Of Living Cells, Paul J. Campagnola, Heather Clark, William A. Mohler, Aaron Lewis (Prof.), Leslie M. Loew

Heather Clark

Second harmonic generation (SHG) has been developed in our laboratories as a high-resolution nonlinear optical imaging microscopy for cellular membranes and intact tissues. SHG shares many of the advantageous features for microscopy of another more established nonlinear optical technique: two-photon excited fluorescence (TPEF). Both are capable of optical sectioning to produce threedimensional images of thick specimens and both result in less photodamage to living tissue than confocal microscopy. SHG is complementary to TPEF in that it uses a different contrast mechanism and is most easily detected in the transmitted light optical path. It can be used to image membrane probes ...


A Comparative Study Of Optical Fluorescent Nanosensors ("Pebbles") And Fiber Optic Microsensors For Oxygen Sensing, Z. Chen-Esterlit, S. F. Peteu, Heather Clark, W. Mcdonald, R. Kopelman Nov 2010

A Comparative Study Of Optical Fluorescent Nanosensors ("Pebbles") And Fiber Optic Microsensors For Oxygen Sensing, Z. Chen-Esterlit, S. F. Peteu, Heather Clark, W. Mcdonald, R. Kopelman

Heather Clark

In this paper we report the use of phase sensitive fluorometry to obtain preliminary results from opto-chemical fluorescent oxygen nanosensors. PEBBLE (Probe Encapsulated By Biologically Localized Embedding) sensors were fabricated by immobilizing tris(4,7-diphenyl—1, 10-phenanthroline)Ru(II) chloride and tris(1,10-phenanthroline)Ru(II) chloride within a polyacrylamide matrix. PEBBLEs have diameters of 20-200 nm and exhibit excellent performance for dissolved oxygen detection. Their performance is compared with micrometer-sized (10-20 μm) optical fiber sensors and free dye in solution. Oxygen sensing ability of PEBBLEs was tested in the presence of other quenchers and compared with free dyes in ...


Sub-Wavelength Plasmonic Readout For Direct Linear Analysis Of Optically Tagged Dna, Jonathan Varsanik, William Teynor, John Leblanc, Heather Clark, Jeffrey Krogmeier, Tian Yang, Jonathan Bernstein Nov 2010

Sub-Wavelength Plasmonic Readout For Direct Linear Analysis Of Optically Tagged Dna, Jonathan Varsanik, William Teynor, John Leblanc, Heather Clark, Jeffrey Krogmeier, Tian Yang, Jonathan Bernstein

Heather Clark

This work describes the development and fabrication of a novel nanofluidic flow-through sensing chip that utilizes a plasmonic resonator to excite fluorescent tags with sub-wavelength resolution. We cover the design of the microfluidic chip and simulation of the plasmonic resonator using Finite Difference Time Domain (FDTD) software. The fabrication methods are presented, with testing procedures and preliminary results. This research is aimed at improving the resolution limits of the Direct Linear Analysis (DLA) technique developed by US Genomics. In DLA, intercalating dyes which tag a specific 8 base-pair sequence are inserted in a DNA sample. This sample is pumped though ...


Surface Morphology Of Platelet Adhesion Influenced By Activators, Inhibitors And Shear Stress, Melanie Groan Watson Oct 2010

Surface Morphology Of Platelet Adhesion Influenced By Activators, Inhibitors And Shear Stress, Melanie Groan Watson

Doctoral Dissertations

Platelet activation involves multiple events, one of which is the generation and release of nitric oxide (NO), a platelet aggregation inhibitor. Platelets simultaneously send and receive various agents that promote a positive and negative feedback control system during hemostasis. Although the purpose of platelet-derived NO is not fully understood, NO is known to inhibit platelet recruitment. NO's relatively large diffusion coefficient allows it to diffuse more rapidly than platelet agonists. It may thus be able to inhibit recruitment of platelets near the periphery of a growing thrombus before agonists have substantially accumulated in those regions.

Results from two studies ...


Theory Of ‘Selectivity’ Of Label-Free Nanobiosensors – A Geometro-Physical Perspective, Pradeep R. Nair, Muhammad A. Alam Jan 2010

Theory Of ‘Selectivity’ Of Label-Free Nanobiosensors – A Geometro-Physical Perspective, Pradeep R. Nair, Muhammad A. Alam

Birck and NCN Publications

Modern label-free biosensors are generally far more sensitive and require orders of magnitude less incubation time compared to their classical counterparts. However, a more important characteristic regarding the viability of this technology for applications in Genomics/Proteomics is defined by the ‘Selectivity’, i.e., the ability to concurrently and uniquely detect multiple target biomolecules in the presence of interfering species. Currently, there is no theory of Selectivity that allows optimization of competing factors and there are few experiments to probe this problem systematically. In this article, we use the elementary considerations of surface exclusion, diffusion limited transport, and void distribution ...