Ultrasensitive engineered two-dimensional metal carbide-based transistor biosensor for point-of-care lung cancer diagnosis via exosomal miRNA profiling

The development of ultrasensitive biosensing platforms for detecting exosomal MicroRNA-21 (miR-21), a critical biomarker for lung cancer, remains a significant challenge in point-of-care diagnostics. Here, we present a two-dimensional metal carbide (MXene)-based field-effect transistor biosensor (Pt-MX-iFETs), engineered with platinum nanowires (PtNWs) to achieve exceptional electrical conductivity and transconductance. This novel metal carbide architecture enables ultralow-concentration miR-21 detection at 0.84 fM, representing one of the most sensitive biosensing platforms reported to date. The superior performance of PtNWs@MXene stems from its unique morphology and enhanced charge transfer properties, facilitating high-affinity miRNA capture and signal amplification. In clinical validation, Pt-MX-iFETs demonstrated favorable correlation with quantitative PCR (R²=0.8529) and successfully discriminated lung cancer patients from healthy controls (p = 0.000139). Receiver operating characteristic (ROC) analysis further confirmed diagnostic efficacy, yielding an AUC of 0.904, with 81.8 % specificity and 81.9 % sensitivity. Our findings highlight the unprecedented sensitivity of metal carbide-based biosensing, enabling reliable exosomal miRNA detection in complex biofluids. With further clinical validation, Pt-MX-iFETs hold transformative potential for early lung cancer screening, real-time disease monitoring, and precision therapy guidance, establishing a new paradigm for ultrasensitive, portable diagnostic systems.