UV-activated biosensor based on molecularly imprinted polymer and carbon quantum dots for lactate measurement

Rapid, non-invasive measurement of lactate in sweat is important for sports and healthcare monitoring. In this work, we have developed a fluorescence biosensor using a mesoporous molecularly imprinted polymer (mMIP) integrated with silica-capped, N-doped carbon quantum dots (Si,N-CQDs) to measure lactate in human sweat. The polymeric structure was formed by using 3-Aminopropyltriethoxysilane (APTES) as the functional monomer, tetraethyl silicate (TEOS) as the cross-linker, and cetyl trimethyl ammonium bromide (CTAB) for creating porous reception sites in the polymer complex. Lactic acid was applied to create the imprinted sites in the polymer structure. The developed sensor was able to measure lactate concentration in a sweat-representing environment, phosphate buffer solution (PBS), over the wide range of 0-120 mM. The sensor showed rapid, selective responses to lactate while exhibiting negligible responses to typical sweat interferents at their representative concentrations-uric acid (UA), ascorbic acid (AA), and glucose (GU) produced responses of 0, 0.029, and 0.018, respectively-and delivered a response of 0.365 at 40 mM lactate. These results indicate that the fabricated sensor platform provides a facile and reliable route to sweat lactate measurement via optical readout, supporting future translation toward portable and wearable implementations.