In-situ AuNPs-embedded NiFe-PBA@AuNPs/MIP core–shell nanocomposite-based wearable electrochemical sensor for sweat multiplexed biomarker monitoring

A flexible wearable electrochemical sensor was developed based on an in-situ Au nanoparticles (AuNPs)-embedded NiFe-Prussian blue analogue (NiFe-PBA) @molecularly imprinted polymer (MIP) core–shell nanocomposite for simultaneous non-invasive monitoring of four key sweat biomarkers: cortisol (Cor), glucose (Glu), lactic acid (Lac), and cholesterol (Cho). Cubic NiFe-PBA acts as a rigid electroactive scaffold to enable probe-free electrochemical signal output, while dopamine-mediated one-pot polymerization achieves in-situ reduction of Au precursors and conformal coating of polydopamine-based molecularly imprinted films. The in-situ embedded AuNPs significantly boost interfacial charge transfer and structural stability, outperforming conventional ex-situ loading in electrochemical activity and cycling durability. Under optimized conditions, the sensor exhibits wide linear ranges, low detection limits (Cor: 26.7 fM; Glu: 0.0187 μM; Lac: 0.029 μM; Cho: 0.2 pM), strong selectivity, good reproducibility, and excellent mechanical stability against bending, twisting, and stretching. Tested using both artificial and real human sweat, this sensor shows good correlation with commercially available test kits and is capable of stable, continuous monitoring for up to 12 h. Coupled with machine learning, the platform accurately identifies human behavioral states with over 97.89% accuracy. This integrated design combines molecular imprinting, electroactive nanocomposites, and flexible electronics, offering a promising strategy for non-invasive, real-time, multiplexed sweat analysis toward personalized health monitoring, exercise physiology, and precision medicine.