The gramicidin-based biosensor: a functioning nano-machine.

摘要: Biosensors combine a biological recognition mechanism with physical transduction technique. In nature, the for high sensitivity molecular detection is modulation of cell membrane ionic conductivity through specific ligand-receptor binding-induced switching ion channels. This effects an inherent signal amplification six to eight orders magnitude, corresponding total flow arising from single channel gating event. Here we describe first reduction this principle practical sensing device, which planar impedance element composed macroscopically supported synthetic bilayer incorporating gramicidin The and reservoir are covalently attached evaporated gold surface. channels have receptor groups (usually antibodies) that permit by analyte binding receptors. device may then be made wide range analytes, including proteins, drugs, hormones, antibodies, DNA, etc., currently in 10(-7)-10(-13) M range. It also lends itself readily microelectronic fabrication transduction. By adjusting surface density receptors/channel components during fabrication, optimum tuned over several magnitude.