A Gold Nanoparticles and MXene Nanocomposite Based Electrochemical Sensor for Point-of-Care Monitoring of Serum Biomarkers.

The development of portable, cost-effective, and highly sensitive biosensors for real-time biomarker detection is crucial for advancing point-of-care testing (POCT) and wearable health monitoring. Here, we present an integrated portable electrochemical sensor (ip-ECS) that combines gold nanoparticles (AuNPs) and MXene-modified screen-printed electrodes (SPEs) with a custom-designed, low-power electronic system for point-of-care monitoring of serum biomarkers. The AuNPs and MXene nanocomposite significantly enhances the electrochemical performance of the SPE by providing a high density of active sites, improved conductivity, and catalytic activity. The detection of two model molecules (DA and UA) validated the feasibility of ip-ECS, achieving detection limits as low as 1.12 and 1.11 μM for UA and DA, respectively. Furthermore, the ip-ECS was successfully applied to detect Cys C in human serum, showing a linear response in the range of 50-5000 ng/mL and a strong correlation (ρ = 0.9556) with conventional latex immunoturbidimetry (LIA). Clinical validation using serum samples from pregnant women revealed elevated Cys C levels in gestational diabetes mellitus (GDM) patients, highlighting the sensor's potential for early GDM risk prediction. The ip-ECS represents a significant step forward in the development of next-generation biosensors for POCT, wearable diagnostics, and personalized medicine.