 Three Extraordinary Graduates: June 8, 2013. From left: Jung Yun Kim, Talin Ayvazian, and Wenbo Yan. Congrats to all! |
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Sub-nanomolar Detection of Prostate Specific Membrane Antigen in Synthetic Urine Kritika Mohan, Keith C. Donavan, Jessica A. Arter, Reginald M. Penner*, and Gregory A. Weiss* J. Am. Chem. Soc. 135 (2013) 7761.  10.1021/ja4028082The sensitive detection of cancer biomarkers in urine could revolutionize cancer diagnosis and treatment. Such detectors must be inexpensive, easy to interpret, and sensitive. This report describes a bioaffinity matrix of viruses integrated into PEDOT films for electrochemical sensing of prostate-specific membrane antigen (PSMA), a prostate cancer biomarker. High sensitivity to PSMA resulted from synergistic action by two different ligands to PSMA on the same phage particle. |
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 The Penner Group, dressed up for the E.K.C. Lee Dinner, UCI, May 30, 2013. Congrats to Mya and Lindsay who both won recognition for their effectiveness as T.A.'s, and to Wenbo who won the Joan Rowland Award for excellence in research. |
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Electrodeposited Light-Emitting Nanojunctions Wendong Xing, Wenbo Yan, Talin Ayvazian, Yong Wang, Eric Potma, and Reginald M. Penner* Chemistry of Materials 25 (2013) 623. 10.1021/cm304001fThe use of prefabricated gold nanogaps provides an expedient way to study light emission from electrodeposited CdSe, Wendong discovered. Light is emitted from these junctions at energies close to the bandgap of CdSe - a first - but the quantum yield for emission is just 10-6. The challenge will be to uncover how this emission process can be made more efficient. |
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Virus-PEDOT Biocomposite Films Keith C. Donavan, Jessica A. Arter, Gregory A. Weiss*, Reginald M. Penner* Langmuir 28 (2012) 12581. 10.1021/la302473jKeith studied the electrodeposition of virus-PEDOT films using an ensemble of methods including AFM, SEM conductive tip AFM, and quartz-crystal microbalance gravimetry. He finds that the concentration of virus particles incorporated into the film is proportional to the concentration of virus in the polymerization solution. A surprising conclusion of his work is that the proportionality factor is 495 - that is, the concentration of virus in the biocomposite film is a factor of 495 higher than the virus concentration in solution. |
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Lithographically Patterned Gold/Manganese Dioxide Core/Shell Nanowires for High Capacity, High Rate, and High Cyclability Hybrid Electrical Energy Storage Wenbo Yan, Jung Yun Kim, Wendong Xing, Keith C. Donavan, Talin Ayvazian, and Reginald M. Penner* Chemistry of Materials 6 (2012) 5627. 10.1021/cm3011474Wenbo prepares a hemicylindrical shell of manganese oxide by electrodeposition onto lithographically patterned gold nanowires to produce hybrid, core-shell nanowires. The gold core functions as a current collector, enabling ultra-long MnO2 nanowires to be electrically addressed. Arrays of these core-shell nanowires, which can be millimeters in total length, exhibit a specific capacity of 1000 F/g and absolute cycle stability in acetonitrile to 1000 cycles. |
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High-Throughput Fabrication of Photoconductors with High Detectivity, Photosensitivity, and Bandwidth. Wendong Xing, Sheng-Chin Kung, Wytze E. van der Veer, Wenbo Yan, Talin Ayvazian, Jung Yun Kim, and Reginald M. Penner* ACS Nano 6 (2012) 5627. 10.1021/nn301567cWhat's faster than a speeding CdSe nanowire? If you're measuring the photoconductivity bandwidth, the answer is: A gold nanogap, covered with CdSe. In this paper, Wendong reports the fabrication and characterization of these devices. Compared with the CdSe nanowire devices we reported just last year, these nanogap photoconductors show a gain that is 1000 times higher, and a bandwidth of 175 kHz! |
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Wafer-Scale Fabrication of Nanofluidic Arrays and Networks Using Nanoimprint Lithography and Lithographically Patterned Nanowire Electrodeposition Gold Nanowire Masters Aaron Halpern, Keith C. Donavan, Reginald M. Penner* and Rob Corn* Analytical Chemistry 84 (2012) 5053. 10.1021/ac3007285Wafer scale (cm2) arrays and networks of nanochannels were created in polydimethylsiloxane (PDMS) from a surface pattern of electrodeposited gold nanowires in a master-replica process. Patterns of gold nanowires with cross-sectional dimensions as small as 50 nm in height and 100 nm in width were prepared on silica substrates using the process of lithographically patterned nanowire electrodeposition (LPNE). Aaron and Keith then used these nanowire patterns as masters to fabricate of inverse replica nanochannels in a special formulation of PDMS. |
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The Surface Scattering-Based Detection of Hydrogen in Air Using a Platinum Nanowire Fan Yang, Keith C. Donavan, Sheng-Chin Kung,, and Reginald M. Penner* Nano Letters 12 (2012) 2924. 10.1021/nl300602mThe performance of a single platinum (Pt) nanowire for detecting H2 in air is reported. A Pt nanowire shows no resistance change upon exposure to H2 in N2, but H2 exposure in air causes a reversible resistance decrease for H2 concentrations above 10 ppm, caused by the reduced electron diffuse scattering at hydrogen-covered Pt surfaces as compared with oxygen-covered platinum surfaces, we hypothesize. Amazingly, Pt nanowires have a limit-of-detection for H2 (LODH2) of 10 ppm; 3 orders of magnitude lower than for Pd nanowires of the same size, as well as a response time that is 1/100th of that seen for pure Pd at [H2]= 1%. |
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