Detecting Interleukin-1β Genes Using a N2O Plasma Modified Silicon Nanowire Biosensor

Abstract

Background Developing ultrasensitive and selective biological sensors has increased in interest for applications in disease detection, drug discovery, and biomedical diagnostics. This paper reports a CMOS-compatible technique for fabricating a silicon nanowire field-effect transistor. The nanowire sensor was applied to detect a fragment of the cancer-related interleukin-1β (IL-1β) gene, which is characterized as an indicator of breast, colon, lung, oral, head, and neck cancers. Methods We used the advanced integrated circuit (IC) technique to fabricate a back-gated nanowire field-effect transistor sensor. The dimensions of the nanowire were 60 nm in width and 20 μm in length. To enhance the sensitivity of the nanowire sensor, a plasma modification treatment with various parameters was employed on the surface of the device. Results The sensitivity of the silicon nanowire field-effect transistor could be improved after a 1-minute N2O plasma treatment, because the morphology of the detection region is rougher after the N2O plasma treatment. Hence, a more functional linker could be bound to the surface, thereby increasing the probability of DNA immobilization and hybridization. We used a specific sequence of the IL-1β gene to verify the sensitivity enhancement of the nanowire sensor by using plasma treatment. Conclusion The sensitivity and detection limit of the plasma-treated sensor can be extrapolated to 0.12/decade and 2.5fM, respectively. The detection results demonstrate that real-time monitoring of the expression of IL-1β using nanowire sensors could be useful for evaluating cancer treatment.