Boron-doped diamond solution-gate field-effect transistor (BDD-SGFET) biosensor for gene mutation detection

Gene mutation is one of the core pathogenic factors in numerous major diseases, making the detection of base mismatches resulting from these mutations critically important in both biological and clinical contexts. This study presents a high-performance boron-doped diamond solution-gated field-effect transistor (BDD-SGFET) biosensor, designed with a diamond microwire structure, for the label-free detection of base mismatches associated with EGFR gene mutations. The simulations examining the impact of variations in diamond microwire dimensions on the electrical properties of BDD-SGFET reveal that increasing the microwire width while reducing its length enhances the electrical performance of the device. Utilizing microwave plasma chemical vapor deposition (MPCVD), photolithography, and plasma etching, we successfully fabricated high-performance BDD-SGFETs featuring microwire structures that demonstrate outstanding transconductance, a reduced threshold voltage, and a limit of detection of 10 pM. Notably, the enhanced performance of the fabricated BDD-SGFET enables the successful identification of DNA molecules with two base-pair mismatches. Furthermore, the device exhibits impressive anti-interference capabilities and exceptional stability in complex environments. These findings highlight the significant potential of microscale BDD-SGFETs as rapid, label-free, and robust platforms for point-of-care testing in genetic mutation analysis pertinent to cancer diagnosis.