Boosted Synergistic Catalytic Performance of Pt Single-Atom Catalyst NiS2/Pt on Wearable Hydrogel Biosensor for Sweat Lactic Acid Analysis

Background

Lactic acid is an important biochemical marker for monitoring tissue oxidation, as its buildup can lead to soreness, fatigue, and potentially serious. Sweat lactic acid detection typically relies on lactic acid oxidase, but the limitations of natural enzymes restrict their use.

Results

A Pt single-atom catalyst (NiS₂/Pt) supported on NiS₂ was prepared via hydrothermal and photochemical fixation methods, and then modified onto a PI flexible electrode. This was integrated with a hydrogel GO/EG-SPB, which exhibits excellent mechanical properties and a PDMS microfluidic channel modified with 2% Silwet-L77. A sensitive, flexible electrochemical sensing platform was constructed for detecting sweat lactic acid. Through density functional theory (DFT) calculations, the optimal adsorption configurations and lowest adsorption energies of LA on the NiS₂/Pt surface were obtained, revealing the catalytic mechanism. The synergistic catalytic effect between Pt single atoms and surrounding Ni atoms significantly improves the sensor’s performance. Based on these unique advantages, the flexible sensing platform shows excellent sensing performance for sweat LA detection, including high selectivity, low detection limits (7.02 μM) and a wide linear range (10 μM - 10 mM).

Significance

The NiS₂/Pt prepared in this study has been successfully applied to accurate and sensitive lactate detection in sweat, which has promising applications in health monitoring and wearable technologies.