Self-powered molecular imprinted polymers-based triboelectric sensor for noninvasive monitoring lactate levels in human sweat

Recent progress in wearable sweat sensors had overcome numerous limitations of conventional sensors and provided methods of collecting molecular-level insight into the dynamics of human bodies. Lactate, a major metabolite in human sweat, can serve as the critical limiting factor for continuing physical activity. However, pioneering works in biosensors for lactate detection in sweat has been encountered major challenges such as noble material usage, immobile power supply, and complicated circuit connection to realize the compact sus-tainable sensing systems. To solve these restrictions, herein, the self-powered molecular imprinted polymers-based triboelectric sensor (MIP-TES) was designed to offer a multifunctional noninvasive approach for specific and simultaneous lactate detection. Free-standing PVDF/graphene flexible electrode modified poly(3-aminophenyl boronic acid) imprinted lactate molecule demonstrated the change of the surface properties after lactate adsorption. MIP-modified electrode revealed the selective lactate sensing over non molecular imprinted polymers (NIP) electrode through the superior and stable signal change with variation of lactate concentration in human sweat. Moreover, MIP modified lactate sensor was further introduced in the triboelectric nanogenerator system to harvest mechanical energy from contact and separation into electrical output. The more adsorbed lactate led to lower energy barriers and decreasing electrical potential when detecting higher lactate concen-tration. Self-power triboelectric lactate sensor could directly power the number of LED lights without an external energy supply. Eventually, it was validated the feasible application of wearable sensors on human skin. The proposed self-powered lactate has created a fascinating horizon in portability, compact, and the real-time analysis of people's perspiration in the future.