Laser-induced graphene nanocomposites with molecularly imprinted polymers and Prussian blue for electrochemical sensing of vitamin B₆ and glucose

Despite the rapid developments of wearable electrochemical sweat sensors, it is still challenging to detect non-electroactive substances such as vitamins with ultralow concentrations in sweat. Herein, this work reports a wearable, regenerable, highly sensitive, and stable sweat sensor based on laser-induced graphene (LIG) nanocomposites with molecularly imprinted polymers (MIPs) and Prussian blue (PBNP) as a redox probe for near-real-time, accurate detection of water-soluble vitamin B₆ in sweat. The resulting sensor exhibits a high sensitivity of 39.95 μA log₁₀ (μM)⁻¹ mm⁻² and a low limit of detection (LOD) of 0.93 nM for vitamin B₆ detection, which can also be adapted for glucose sensing with a sensitivity of 19.33 μA log₁₀ (μM)⁻¹ mm⁻². Combined with a microfluidic module, the integrated sweat sensing system provides opportunities to continuously monitor sweat vitamins and other biomarkers with trace concentrations during exercise in near-real-time. The reported wearable sweat sensing platform unlocks opportunities to noninvasively track nutrients for personalized dietary suggestions, offering significant potential to support precision nutrition.