Collagen/rGO/tannin hydrogels with a programmable biointerface for tunable electrical conductivity and antioxidant capacity in tissue regeneration.

Restoring the endogenous bioelectric field while simultaneously protecting healing tissue from mechanical and oxidative stress remains a major challenge for next-generation wound dressings. Here we present an interface-programmed collagen hydrogel that integrates dopamine-reduced graphene oxide (rGO-PDA), polyethylene glycol (PEG) and condensed tannins (TA) into a single supramolecular network. rGO-PDA provides electronic pathways; TA forges multivalent π-π and hydrogen-bond bridges that immobilize rGO within the fibrillar matrix, confer radical-scavenging capacity and compatibilized the organic/inorganic phases; PEG acts as a hydrophilic spacer that tunes porosity and plasticity. Compared with the PEG-plasticized collagen control, the optimized COL/PEG20/TA10 formulation increased the storage modulus fourfold to 47 kPa, doubled the critical strain, raised the thermal decomposition onset by 80 °C and achieved stable conductivities of 10.3 mS/cm, comparable to native skin. The same interfacial design lowered the water-contact angle to 33 °, raised swelling to 150 % and enabled a biphasic release of TA that maintained 30 % DPPH inhibition for 4 h. Extracts enhanced human dermal fibroblast viability to 151 ± 5 % and accelerated in vitro scratch closure to > 95 % in 48 h. In a porcine full-thickness model the hydrogel achieved complete, scar-free re-epithelialization and highly organized dermal architecture within 21 days, while rabbit and guinea-pig tests confirmed it to be non-irritant. These results demonstrate that molecularly engineered collagen/rGO/TA interfaces can synchronously deliver mechanical reinforcement, bioelectronic stimulation and antioxidant defense, providing a scalable, all-natural platform for advanced wound management.