National Cancer Institute’s Alliance for Nanotechnology in Cancer says that a new method to position nanowires can revolutionize the future of microfluidic diagnostic devices built around nanowire detectors:
The team, led by Hsian-Rong Tseng, Ph.D., of the University of California, Los Angeles, and James Health, Ph.D., of the California Institute of Technology, reported their work in the journal Chemical Communications.
The researchers create the nanowires using standard microelectrodes built into the microfluidics device specifically for the purpose of carrying out electrochemical reactions within the channels of the device. This allows them to use the microfluidic channels to introduce the precursor molecules, or monomers, needed to create the conducting polymer nanowires and trigger an electrochemical reaction at the exact place where the nanowires are needed to function as biomolecule detectors. This reaction causes the monomers to link to one another, forming the conducting polymer nanowires. This process can create two different types of polymer nanowires, one made of polyaniline, the other of polypyrrole. The chemical reactions are completed within 40 minutes.
Once formed, the nanowires can function immediately as detectors, with the electrodes used to form the nanowires now functioning as the circuitry that connects the nanowires to electrical signal recorders. The investigators demonstrate that these detectors are highly sensitive to changes in pH and to changing ammonia concentrations, though they note that these nanowires should be able to be used to detect a wide range of biomolecules.