Label-free and ultrasensitive detection of microrna biomarkers in lung cancer cells based on silicon nanowire FET biosensors

MicroRNAs (miRNAs) have been regarded as biomarkers for early-stage diagnosis of cancer. Due to their short length, low abundance, and very similar sequences, an attractive approach that is ultrasensitive and label-free is extremely demanded. Here we report the design of a novel semiconducting silicon nanowire field-effect transistor (SiNW-FET) biosensor array for ultrasensitive label-free and real-time detection of miR-21. Optical lithography and anisotropic self-stop etching were employed to guarantee low cost batch production for SiNWs. The working conditions of the nanosensor were firstly optimized through pH sensing experiment. This SiNW-FET nanosensor under optimal conditions revealed ultrahigh sensitivity for repaid and reliable detection of 1 fM miR-21 and high specificity for single-nucleotide polymorphism discrimination.