Microfluidic electrolyte-gated TiS3 nanoribbons-based field-effect transistor as ultrasensitive label-free immunosensor for prostate cancer marker analysis

Early detection of prostate cancer, the second main cause of death in men, with robust assay platforms by using the appropriate biomarkers is of great importance for diagnosis and follow-up of disease under treatment. The aim of this research is to investigate how novel TiS₃ nanoribbons can be used as a channel material in the microfluidic electrolyte-gated field-effect transistor (FET), with the goal of developing a label-free immunosensor for the sensitive, selective, and rapid detection of PSA as a cancer marker in both PBS and human serum samples. To create an active channel material, the TiS₃ nanoribbons were deposited onto the FET surface through a drop-casting process, and the surface of the channel was subsequently modified with an anti-PSA monoclonal antibody. The electrical properties of the microfluidic electrolyte-gated TiS₃ nanoribbon-based FET were characterized, and the results showed that it exhibited a depletion-mode n-type behavior with a field-effect mobility of 2.3 × 10⁻³ cm²/Vs, an I_on/I_off current ratio of 4.12, and a subthreshold swing (SS) of 914.1 mV/decade. As the concentration of PSA increased from 0.1 fg/mL to 10 pg/mL, there was a corresponding increase in the drain current with a high sensitivity of 2.2665 nA/decade and a detection limit of 0.04 fg/mL. Integrating the electrolyte-gated FET with the microfluidic channel resulted in improved performance of the microfluidic electrolyte-gated FET immunosensor. The combination of these two components led to better control and delivery of small sample volumes to the surface of the electrolyte-gated FET, which improved the repeatability of the obtained data. Based on the results obtained from the microfluidic immunosensor, it can be inferred that the developed platform has the potential to be an excellent candidate for point-of-care cancer diagnosis and therapeutic monitoring.