Smartphone-integrated Ti2C quantum dots-alginate hydrogel patch for colorimetric monitoring of sweat total antioxidant capacity

A high-performance Ti₂C QDs-TMB sensor was developed for sensitive, interference-resistant TAC detection. • The dual-crosslinked hydrogel patch demonstrates excellent wearability and biocompatibility. • A smartphone-integrated platform enables real-time, visual analysis of TAC in sweat. Monitoring total antioxidant capacity over time is crucial for understanding the progression of oxidative stress in chronic diseases. However, traditional single-point measurements provide only static information and fail to capture dynamic fluctuations and long-term trends. Existing TAC methods rely on specialized equipment and lack biointegration, severely limiting their widespread application in both clinical and home settings. Against this background, this study developed a novel, highly sensitive, and anti-interference TAC detection method, which was based on the catalytic oxidation properties of Ti 2 C MXene quantum dots (Ti 2 C QDs) as the core response mechanism. By employing a two-step cross-linking mechanism, the Ti₂C QDs-TMB colorimetric system was encapsulated within a sodium alginate hydrogel to fabricate a flexible, visual sensor patch (TQ-SA). Using a self-developed smartphone application to analyze patch color changes, the TAC (expressed as ascorbic acid equivalents) in artificial sweat was quantitatively measured in real time, with a detection limit of 2.745 μM. This work leverages the high catalytic activity of MXene quantum dots and the portability of mobile devices to provide a viable research strategy for dynamic antioxidant wearable sensor technology. Ti₂C MXene quantum dots are synergistically integrated into a dual-crosslinked sodium alginate hydrogel matrix, yielding a highly flexible and wearable sensing platform. By leveraging smartphone-based image acquisition and digital colorimetric analysis, the patch facilitates sensitive, real-time quantification of total antioxidant capacity (TAC). Download: Download high-res image (160KB) Download: Download full-size image