Nanomosaic Network for the Detection of Proteins Without Direct Electrical Contact

Abstract A nanomosaic network of metallic nanoparticles for the detection of ultralow concentrations of proteins is reported, which uses two planar microelectrodes embedded in a microchip that permit generation of capacitive coupling to the nanomosaic system without the need for direct electrical contact with the channel. By tailoring the microchannel surface using a sandwich configuration of polyethylene terephthalate/gold nanoparticles/poly(L‐lysine), the surface charge can be modified following biomolecular interactions and monitored using a noncontact admittance technique. This nanodevice system behaves like a tunable capacitor and can be employed for the detection of any kind of molecule. The femtomolar detection of an anionic protein, such as β‐lactoglobulin in phosphate‐buffered saline medium, is taken as an example.