Ultra-fast and sensitive silicon nanobelt field-effect transistor for high-throughput screening of alpha-fetoprotein

In this paper, we described a novel fabrication technique for Silicon nanobelt field-effect transistors (SiNB FETs) based on the Local Oxidation of Silicon (LOCOS) process widely utilized in the manufacturing of microelectronics components and explore it to screened alpha-fetoprotein (AFP). LOCOS process is used as it enables thorough compatibility with complementary metal oxide semiconductor (CMOS) technology. Thus, the need for expensive lithography tools to define the nanoscale pattern is avoided. The SiNB FETs emerges as a powerful biosensor for ultrasensitive, label-free for biological/chemical detection and direct electrical readout. The analytical sensing results of the fabricated SiNB FETs employed as a biomolecular sensor for the early, real-time, and label-free screening of AFP can be understood in term of the change in charge density at the silicon nanobelt surface after functionalization. It is observed that, by tuning the gate voltage, the electrical linearity response of the system towards AFP extends its concentration range from 3 ng/mL to 100 ng/mL, allowing the screening of hepatocellular carcinoma (HCC). These results indicate that the detection of AFP under our direct, label-free, and ultrasensitive biosensor in a microfluidic channel could be one of the promising state-of-the-art techniques applicable as an AFP detector in real samples.