59 nanotimes News in Brief

By systematically investigating a large number of single-and double-gated bilayer graphene (BLG) devices, researcher at University of California, University of Maryland, University of Texas at Austin, University of Pennsylvania, California Institute of Technology, and National High Magnetic Field Laboratory (all USA) observed a bimodal distribution of minimum conductivities at the charge neutrality point.

Wenzhong Baoa, Jairo Velasco, Fan Zhang, Lei Jinga, Brian Standley, Dmitry Smirnov, Marc Bockrath, Allan H. MacDonald, and Chun Ning Lau: Evidence for a spontaneous gapped state in ultraclean bilayer graphene, In: PNAS Early View, June 8, 2012, DOI:10.1073/pnas.1205978109:

http://dx.doi.org/10.1073/pnas.1205978109

Researchers at School of Electrical and Computer Engineering, Purdue University (US), propose in PNAS a Flexure-FET (flexure sensitive Field Effect Transistor) ultrasensitive biosensor that utilizes the nonlinear electromechanical coupling to overcome the fundamental sensitivity limits of classical electrical or mechanical nanoscale biosensors. The stiffness of the suspended gate of Flexure-FET changes with the capture of the target biomolecules, and the corresponding change in the gate shape or deflection is reflected in the drain current of FET. The Flexure-FET is configured to operate such that the gate is biased near pull-in instability, and the FET-channel is biased in the subthreshold regime. The proposed sensor can detect both charged and charge-neutral biomolecules, without requiring a reference electrode or any sophisticated instrumentation, making it a potential candidate for various low-cost, point-of-care applications. © PNAS

Ankit Jain, Pradeep R. Nair, and Muhammad A. Alam: Flexure-FET biosensor to break the fundamental sensitivity limits of nanobiosensors using nonlinear electromechanical coupling, In: PNAS, Vol. 109, No. 24, June 12, 2012, Pages 9304-9308, DOI: 10.1073/pnas.1203749109:

http://dx.doi.org/10.1073/pnas.1203749109

Researcher at Nanjing University (China), and Stanford University (US) report in PNAS a scalable and versatile synthesis of multifunctional polyaniline (PAni) hydrogel with excellent electronic conductivity and electrochemical properties. With high surface area and three-dimensional porous nanostructures, the PAni hydrogels demonstrated potential as high-performance supercapacitor electrodes with high specific capacitance. The scalable synthesis and excellent electrode performance of the PAni hydrogel make it an attractive candidate for bioelectronics and future-generation energy storage electrodes. © PNAS

Lijia Pan, Guihua Yu, Dongyuan Zhai, Hye Ryoung Lee, Wenting Zhao, Nian Liu, Huiliang Wang, Benjamin C.-K. Tee, Yi Shi, Yi Cui, and Zhenan Bao: Hierarchical nanostructured conducting polymer hydrogel with high electrochemical activity, In: PNAS, Vol. 109, No. 24, June 12, 2012, Pages 9287-9292,  DOI:10.1073/pnas.1202636109:

http://dx.doi.org/10.1073/pnas.1202636109