2D MoS2-based flexible optoelectronic for biosensing

In this study, we present a flexible, optoelectronic molybdenum disulfide (MoS 2 ) based field-effect transistor (FET) biosensor designed for the real-time detection of human immunoglobulin G (HIgG) proteins in liquid-phase environments. To address the limitations of high resistivity and low output current typically associated with MoS 2 -based FETs , we employed a photonic strategy integrating red light illumination (650 nm) precisely matched to the band gap of monolayer MoS 2 . This strategy enhanced the device’s performance, achieving a 2.4-fold increase in sensitivity (0.115 per Log[ng/mL]) and reducing the limit of detection (LOD) from 85.9 ng/mL to 7.57 ng/mL under illumination. The biosensor was fabricated on a flexible Kapton substrate, enabling cost-effective production and compatibility with wearable diagnostics. An atomic layer deposited (ALD) aluminum oxide (Al 2 O 3 ) passivation layer provided device protection and facilitated biofunctionalization with antibodies via linkers. Specific binding of HIgG proteins to the immobilized antibodies resulted in measurable changes in the output current, which were detected as the sensing signal. This platform demonstrated excellent specificity, negligible cross-reactivity with non-target proteins, and robust performance in both simple buffer solutions and complex artificial urine matrices. The MoS 2 -based biosensor demonstrated durability with stable responses during extended static bending tests . By eliminating applied gate voltages and utilizing optoelectronic enhancement, this work advances energy-efficient, reliable, high-performance biosensors. It highlights the potential of biofunctionalized MoS 2 platforms for early disease diagnostics and future innovations in flexible, wearable biosensing technologies. • Flexible MoS 2 biosensors with 650 nm red LED for real-time protein detection. • 2.4-fold increase in sensitivity with improved limit of detection achieved. • High sensitivity and selectivity demonstrated in simple and complex matrices.