NIR-driven electron transfer for in situ gelation and enhanced hydrogen therapy

Hydrogen therapy has shown significant promise in improving wound healing by mitigating oxidative stress and inflammation. However, its therapeutic efficacy is constrained by limited delivery methods and insufficient bioavailability of hydrogen at wound sites. Herein, we design NIR-light triggered in situ gelation platform comprising ternary polymer dots as the photocatalyst, ascorbic acid as an electron mediator, and poly(ethylene glycol) diacrylate (PEGDA) as the polymeric matrix. The blended components of ternary Pdots enable the extended light absorption and cascading energy level alignment, leading to a marked increase in hydrogen generation compared to binary Pdots. Following local injection of the mixed precursor solution at the wound site and subsequent 700 nm light exposure, the in-situ gelation of PEGDA is initiated by ascorbate free radicals, obviating the need for commercial photoinitiators. The resulting hybrid hydrogel retains water content and photocatalysts, enabling prolonged hydrogen evolution under NIR light. The hydrogen produced by the catalytic action of the ternary Pdots effectively scavenges reactive oxygen species at the wound site and promotes macrophage M1-to-M2 phenotype transition. The immunomodulatory effects of this light-triggered platform demonstrate significant therapeutic potential, accelerating wound repair through enhanced hydrogen delivery strategy.