Applying AuNPs/SWCNT to fabricate electrical nanogap device for DNA hybridization detection

AuNPs/SWCNT, a hybrid nanomaterial which is single-walled carbon nanotube (SWCNT) modified with gold nanoparticles (AuNPs), has great application prospects for chemical and biological sensors. For the innate nanogap between tiny AuNPs deposited on sidewall of SWCNT, AuNPs/SWCNT is suitable for the fabrication of simple and effective electrical signal switching devices. Here, we develop a novel strategy of applying AuNPs/SWCNT to fabricate nanogap device for DNA hybridization detection. The detection strategy is based on the target DNA mediating the catalytic activity of the AuNPs by desorbing the probe DNA from AuNPs. The signal transduction depends on the growth of tiny AuNPs which is closely related to the AuNPs catalytic activity. Sensing occurs at the tiny AuNPs growing and connecting into a continuous nanowire along the SWCNT, leading to a conductimetric response. The biosensing device can detect target DNA with the detection limit of 1 pM and the ability to discriminate triple and quintuple base pair mismatches.