Adjacent Fe-Pt atomic site synergistically boosting wearable biosensor performance in sweat analysis

Abstract

Wearable electrochemical sensors have enormous potential in real-time and continuous monitoring of an individual’s physiological and biological state. In electrocatalysis, single-atom catalysts (SACs) with Fe-N4 active centers are attracting interest for their nearly complete metal utilization rate and unique unsaturated coordination configuration. Yet, their reliance on a single active site leads to a fixed adsorption mode for oxygen intermediates such as OH, greatly constraining design flexibility and catalytic performance. This study explores the synergistic effects between Fe-N4 and Pt-N4 active sites and their impact on the electrocatalytic activity towards uric acid (UA) and dopamine (DA). Proximal Pt-N4 atoms facilitate the activation of OH species on the Fe-N4 site and modulate the rehybridization of Fe d orbitals, thereby enhancing the adsorption of oxygen intermediates. This mechanism accelerates the overall electrocatalytic process for both UA and DA. Moreover, a non-swelling double network hydrogel is designed by combining chitosan with the P(AA-MEA)-Fe network. As a practical application, the non-swelling hydrogel channel, when combined with FeN4/PtN4 catalyst, successfully achieves real-time on-site detection of skin sweat biomarkers.