Development of a complementary metal-oxide-semiconductor-based biosensor system enabling in situ real-time polymerase chain reaction on chip for onsite detection, serotyping, and differentiation of foot-and-mouth disease.

A novel complementary metal-oxide-semiconductor (CMOS) photo sensor (CPS)-integrated multiplex rRT-PCR platform was developed to enable rapid, on-site detection of foot-and-mouth disease virus (FMDV). Unlike conventional assays requiring lengthy RNA extraction and bulky hardware, this system combines direct rRT-PCR amplification with miniaturized optical and thermal modules on a single semiconductor chip. A silicon-based microheater and dual-wavelength fluorescence filters were incorporated to maintain precise thermal cycling and high-fidelity signal acquisition. Through an optimized workflow, the entire process from RNA exposure to FMDV gene amplification and result output is completed within 100 min, reducing the overall time by approximately half compared to conventional laboratory-based rRT-PCR. Analytical evaluations revealed a detection limit of approximately 10° to 10 TCID/mL, comparable to established platforms, and robust performance was maintained even with direct testing of crude samples. Field validation using clinical specimens from a 2023 FMD outbreak in South Korea yielded 100 % diagnostic sensitivity and specificity. Additionally, real-time data transmission facilitated by cloud connectivity enhances its utility for large-scale surveillance and outbreak management. Overall, this CMOS-based CPS-rRT-PCR device offers an efficient, field-deployable molecular diagnostic solution for FMDV and potentially other transboundary infectious diseases.