Press Release, October 13, 2014 / EE News 7
A New Three-Dimensional Nanomesh Nanowire Biosensor
POSTECH–NASA collaboration could enable faster, more accurate detection of diseases and harmful substances.
Professor Jung-Soo Lee and doctoral student Gihyeon Kim of POSTECH Electrical Engineering, collaborating with NASA researchers, developed a new nanowire biosensor using a suspended three-dimensional honeycomb mesh of repeating Y-shaped junctions. It offers substantially improved electrical properties and highly sensitive hydrogen-ion detection compared with straight nanowires, advancing sensors for disease diagnosis, drug development, and environmental contaminant detection.
Suspended structures can improve sensitivity by avoiding effects from substrate impurities. Conventional nanowires, however, have very large aspect ratios, described as height-to-length ratios in the source, causing collapse or adhesion and making suspended structures difficult to fabricate. Repeated Y junctions improve mechanical stability and provide more surface area than straight structures.
Using nanoscale semiconductor processing on silicon-on-insulator wafers, the team fabricated suspended honeycomb nanowires 30 nm wide. Electrical characterization and hydrogen-ion detection experiments demonstrated potential for highly sensitive biosensors.
The team said, “The core technology is a stable, highly sensitive suspended three-dimensional sensor using honeycomb nanowires. It can support medical diagnosis as well as environmental and food sensor platforms, opening a path to products that detect diseases and harmful substances faster and more accurately.”
The findings were selected as a Featured Article and cover paper in Nanotechnology, published by the UK's Institute of Physics, on August 29. End / EE.
Suspended structures: substrate surface charges in conventional nanowire sensors form an electrical double layer, obstructing circulation of charged targets and weakening target binding at the sensing surface, reducing sensitivity. Separating nanowires from the substrate in a suspended 3D structure permits detection over their entire surface and removes substrate interference with target circulation, enabling high sensitivity.
Related articles: Electronic Times, Yeongnam Ilbo, Gukje News, Gyeongsang Maeil, and Newsis.