Integrated Point-of-Care SiNW biosensors

A SiNW sensor consisting of a SiNW, functionalised with a “bioreceptor” which can interact selectively with a target biomarker, has been developed. By attaching aniline to a SiNW, via coupling with an aryl diazonium salt, the amino group of the aniline molecule has been used to graft antibodies - targeted against 8-hydroxydeoxyguanosine (8-OHdG) - onto the SiNW surface. Antibody attachment to SiNW surfaces has been verified using Laser Scanning Confocal Microscopy (LSCM) to detect quantum-dot labelled antibodies bound to the SiNW surface. The current-voltage (I–V) characteristics of the silicon nanowire devices show an increase in resistivity upon chemical functionalization with aniline. A decrease in resistivity is seen on binding of the bioreceptor antibody. The antibody-functionalised SiNW sensor has been used to detect binding of the 8-OHdG biomarker to the SiNW surface within seconds of exposure. SiNW devices have been bonded to a disposable “bio-smartcard” and subsequently slotted into an electronic readout device. This system has been specifically developed for Point-of-Care (POC) use.