Near-Infrared Photoenzymatic Catalysis at ppb Levels Enables Ultrahigh-Molecular-Weight Polymers

In principle, photocontrolled radical polymerization via near-infrared (NIR) irradiation offers spatiotemporal precision, deep tissue penetration, and biocompatibility. However, its utility is hindered by low efficiency and restricted access to high-molecular-weight polymers. To address these challenges, we report a new supramolecular NIR photoenzyme (SNIRPE) system comprising glucose oxidase (GOx) and tetrasulfonated zinc phthalocyanine (ZnPcS₄^-) that combines enzymatic deoxygenation with photoredox catalysis. SNIRPE involves a spatially confined cascade mechanism: GOx-generated H₂O₂ is photodecomposed in situ by ZnPcS₄^- under NIR irradiation to produce hydroxyl radicals (•OH). This enables oxygen-tolerant, high-throughput, reversible addition-fragmentation chain transfer (RAFT) polymerization across microliter-to-100 mL volumes, achieving ultrahigh molecular weights (UHMWs, M_n > 1000 kg mol^-1, Đ < 1.20) with ultralow catalyst loadings (50 ppb ZnPcS₄^-, which is 3-4 orders of magnitude lower than conventional NIR photoredox systems). Scalability is demonstrated through 100 mL batch synthesis, while polymerization through porcine tissue underscores its biomedical utility. By combining enzymatic efficiency with photoredox versatility, longstanding problems in NIR-driven polymer synthesis have been eliminated.