One possible sensor design will use receptor molecules, such as antibodies, attached to a cantilever made of UNCD. The cantilever is connected to CMOS electronics that vibrate it using an electric field. Receptors that come in contact with the right toxin or protein in a gas or liquid sample lock onto it, making the cantilever heavier and changing the vibration frequency.
The technique relies on ultra-nanocrystalline diamond (UNCD), which can be doped with nitrogen and made highly electrically conductive. "We immerse UNCD in a solution and apply voltages, which creates radicals that react with the diamond surface to form strong carbon-carbon bonds," says Jian Want, Argonne researcher. This layer of organic radicals can be used to anchor biomolecules, an important step in developing sensors to detect anthrax, monitor blood sugar levels, or handle other lab-on-a-chip functions.
The sensors will need to use biomolecules, and this technique gives engineers a way to attach them to a chip or other silicon-based features.
