An ultrasensitive flexible biosensor enabled by high-performance graphene field-effect transistors with defect-free van der Waals contacts for breast cancer miRNA fast detection.

MicroRNAs (miRNAs) present in bodily fluids such as blood, saliva, and urine hold significant potential for both diagnosing and prognosing breast cancer. However, the development of flexible wearable field-effect transistor (FET) breast cancer miRNA biosensors still faces many challenges. Herein, we developed an ultrasensitive flexible biosensor based on a high-performance FET with defect-free van der Waals contacts for breast cancer miRNA fast detection. The flexible biosensor achieves a limit of detection (LOD) as low as 1.92 fM, a wide linear detection range of 10 fM-100 pM, and a short detection time of 10 min for fast detection of miRNA-155, which is approximately a 5-fold lower LOD compared to conventional graphene FET biosensors. Additionally, the sensor maintains stable sensing performance even after 100 bending/relaxation cycles. The defect-free graphene channel and excellent electrical properties of the flexible FET contribute to the high performance of the biosensor. The biosensor effectively differentiates miRNA levels in serum between breast cancer patients and healthy individuals, proving the possibility of practical application. It also successfully detects miRNA in sweat by attaching the biosensor to the human body, demonstrating its promise for non-invasive health monitoring as a wearable device. This easy-to-fabricate, high-performance flexible biosensor advances cancer biomarker analysis and wearable health monitoring technology.