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Reginald M Penner

Publications and source records attributed to Reginald M Penner.

5 recordsLinked to original sources
PubMed2006

Virus electrodes for universal biodetection.

A dense virus layer, readily tailored for recognition of essentially any biomarker, was covalently attached to a gold electrode surface through a self-assembled monolayer. The resistance of this "virus electrode", Z(Re), measured in the frequency range from 2 to 500 kHz in a salt-based pH 7.2 buffer, increased when the phage particles selectively bound either an antibody or prostate-specific membrane antigen (PSMA), a biomarker for prostate cancer. In contrast to prior results, we show the capacitive impedence of the virus electrode, Z(Im), is both a noisier and a less sensitive indicator of this binding compared to Z(Re). The specificity of antibody and PSMA binding, and the absence of nonspecific binding to the virus electrode, was confirmed using quartz crystal microbalance gravimetry.

Bacteriophage M13↗
PubMed2005

Photoconductive cadmium sulfide hemicylindrical shell nanowire ensembles.

We report the synthesis and characterization of hemicylindrical shell nanowires (HSNWs) composed of nanocrystalline cadmium sulfide (CdS). CdS HSNWs were synthesized by first electrodepositing microcrystalline cadmium (Cd) nanowires by electrochemical step-edge decoration on graphite electrode surfaces and then converting these Cd nanowires into CdS by exposure to H2S at elevated temperature. These nanowires had a hemicylindrical shell morphology that was produced by the Kirkendall effect, involving disparate rates for diffusion of Cd and S atoms within the nascent CdS layer during the conversion from Cd to CdS. The outer diameter of the CdS HSNWs was 1.6-2.4 times that of Cd precursor nanowires and was adjustable over the range from 116 to 550 nm. CdS HSNWs showed strong, band-edge photoluminescence at 2.45 eV and a fast, reversible, and stable photoconductivity response in air characterized by "on" and "off" times of less than 15 ms.

Journal Article↗
PubMed2004

Electrodeposition of metal nanostructures by galvanic displacement powered with insoluble crystals of a ferrocene derivative.

The deposition of metal nanostructures (wires and particles) on a graphite surface from an aqueous electrolyte solution was induced by galvanic displacement, via the oxidation of insoluble crystals of a ferrocene derivative (either n-butyl ferrocene or decamethyl ferrocene) present on the same substrate. Micron-to-millimetre-scale crystallites of decamethyl ferrocene were deposited on the graphite surface by evaporation from a solution of a nonpolar solvent (1,2-dichloroethane). Immersion of this modified surface into a dilute solution of a metal ion (e.g., CuII, AgI, PdII, PtII and others) caused the deposition of metal nanoparticles at step edges present on the graphite surface. The reducing equivalents required for the metal deposition process are provided by oxidation of the ferrocene derivative on the surface, as directly evidenced by elemental analysis and chronoamperometric experimental data presented here.

Journal Article↗
PubMed2003

Metal nanowire arrays by electrodeposition.

We describe two related methods for preparing arrays of nanowires composed of molybdenum, copper, nickel, gold, and palladium. Nanowires were obtained by selectively electrodepositing either a metal oxide or a metal at the step edges present on the basal plane of highly oriented pyrolytic graphite (HOPG) electrodes. If a metal oxide was electrodeposited, then nanowires of the parent metal were obtained by reduction at elevated temperature in hydrogen. The resulting nanowires were organized in parallel arrays of 100-1000 wires. These nanowires were long (some > 500 microns), polycrystalline, and approximately hemicylindrical in cross-section. The nanowire arrays prepared by electrodeposition were also "portable": After embedding the nanowires in a polymer or cyanoacrylate film, arrays of nanowires could be lifted off the graphite surface thereby facilitating the incorporation of metal nanowire arrays into devices such as sensors.

Journal Article↗