Synthetic hydrogel polymer nanoparticles as a structural mimic of carbonic anhydrase

Current synthetic analogs of carbonic anhydrase (CA) often lack moisture stability and structural flexibility compared with natural CA. Here, we introduce a novel approach, crafting moisture-stable zinc-coordinated synthetic hydrogel polymer nanoparticles (HNPs) as CA mimics. These HNPs, formed through zinc ion and vinyl imidazole coordination followed by free radical polymerization, display unique features. Ligand exchange generates nucleophilic Zn-OH groups, while a hydrophobic monomer modulates the hydrophobic microenvironment surrounding the active center. Our CA mimics exhibit exceptional catalytic performance, with a kcat/Km value of 4,087.2 M−1 s−1, outperforming natural CA by 16.8 times. They also enable rapid CO2 hydration. We validate N3ZnOH catalytic centers through X-ray photoelectron spectroscopy (XPS) and synchrotron-based X-ray absorption spectroscopy (SR-XAS) and elucidate the mechanism via density functional theory (DFT) simulation. Integrated into mixed-matrix membranes (MMMs), they exhibit outstanding CO2 separation performance, surpassing Robeson plot limits and previous natural and mimetic CA-based MMMs. This work highlights the promise of synthetic CA mimics in catalysis and gas separation.