Assembly of Sequence-Defined Peptoids into Biomimetic Nanostructures Promotes Enhanced Carbon Dioxide Sequestration

Artificial enzymes that mimic natural carbonic anhydrase (CA) enzymes have recently received significant attention due to their low-cost synthesis and superior stability compared to their natural counterparts for their promising applications in the promoted CO₂ sequestration. While most of these CA mimics focus on mimicking the active sites of CAs, limited efforts have been made to manipulate the arrangement and microenvironment of these active sites for high catalytic activity. Herein, we report the assembly of sequence-defined peptoids into crystalline nanomaterials with controlled microenvironment of active sites as CA mimetics for tunable catalytic ester hydrolysis to achieve promoted CO₂ precipitation. We demonstrate that the morphology, crystallinity, chemistry of hydrophilic domain, and metal-ligand coordination of peptoid assemblies are significant for catalytic activity and selectivity on hydrolysis of ester (4-nitrophenyl acetate). In addition to experimental studies, molecular dynamics (MD) simulations were carried out to understand peptoid catalysts activity based on binding energy and local microenvironment. We further demonstrate that these peptoid-based nanoenzymes are highly stable, recyclable, and highly efficient in promoting CO₂ sequestration and CaCO₃ mineralization Solution-state nuclear magnetic resonance (NMR) was utilized to elucidate the mechanism of CO₂ hydration and sequestration by peptoid catalysts.