Highly Sensitive Detection of Influenza A (H1N1) Virus With Silicon Nanonet BioFETs

Highly sensitive silicon-nanonet biologically active field-effect transistors (BioFETs) for the detection of influenza A (H1N1) virus have been demonstrated using a top-down process. The BioFETs show excellent intrinsic electrical characteristics, such as a low threshold voltage of 0.7 V and high on/off current ratio of ~10⁷. The sensing characteristics were measured at room temperature with various concentrations of H1N1 virus in a range of 10 pg/ml - 100 ng/ml. The current-related sensitivity (<inline-formula> <tex-math notation="LaTeX">${S}_{ {I}}$ </tex-math></inline-formula>) shows a higher value in the subthreshold regime, where <inline-formula> <tex-math notation="LaTeX">${S}_{ {I}}$ </tex-math></inline-formula> is strongly correlated with the subthreshold swing (<italic>SS</italic>). The voltage-related sensitivity (<inline-formula> <tex-math notation="LaTeX">${S}_{ {V}}$ </tex-math></inline-formula>) shows almost constant behavior from the subthreshold regime to the linear regime. The limit of detection (LOD) was 10 pg/ml, which is 6 times lower than values previously reported for FET-type sensors. In addition, the nanonet sensors exhibit high specificity to influenza A virus with negligible false positive for influenza B virus.