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Biomedical Engineering and Bioengineering Commons

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Full-Text Articles in Biomedical Engineering and Bioengineering

Optochemical Nanosensors For Intracellular Chemical Measurement, Raoul Kopelman, Michael T. Miller, Murphy Brasuel, Heather Clark, Marion Hoyer, Martin Philbert Nov 2010

Optochemical Nanosensors For Intracellular Chemical Measurement, Raoul Kopelman, Michael T. Miller, Murphy Brasuel, Heather Clark, Marion Hoyer, Martin Philbert

Heather Clark

The development of a submicron optical fiber "supertip" has provided advantages over previously produced submicron tips, such as facilitating insertion of these sensors into cells while minimizing damage to the cell membrane. Fiber optic ion correlation-based nanosensors for sodium, potassium and chloride employing these "supertips" have been applied to the monitoring of ion concentrations in single mouse oocytes. These sensors have also been used to monitor the effect of an ion channel-blocking agent. In order to address the challenge associated with single-cell simultaneous measurement of multiple analytes, the use of submicron optical fiber multiprobes has been explored.


Novel Optical Biosensors Using A Gold Colloid Monolayer Substrate, Heather Clark, Greg Merritt, Raoul Kopelman Nov 2010

Novel Optical Biosensors Using A Gold Colloid Monolayer Substrate, Heather Clark, Greg Merritt, Raoul Kopelman

Heather Clark

A novel optical biosensor matrix has been developed to exploit the native fluorescence of certain proteins. This matrix uses a gold colloid monolayer attached to an end of a fiber as a substrate for protein attachment. The effect of the gold monolayer size has been investigated through the techniques of fluorescence, scanning electron microscopy, and transmission electron microscopy. It has been shown that the size ofthe gold colloid does produce a marked difference in the fluorescence intesity measured. It is surmised through the use of microscopy techniques that the intensity changes seen in the fluorescence emission are not a result …


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 solution. While PEBBLEs have been developed for minimally invasive …


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 …