Mimic Carbonic Anhydrase Using Metal-Organic Frameworks for CO2 Capture and Conversion

Carbonic anhydrase (CA) is a zinc-containing metalloprotein, in which the Zn active center plays the key role to transform CO₂ into carbonate. Inspired by nature, herein we used metal-organic frameworks (MOFs) to mimic CA for CO₂ conversion, on the basis of the structural similarity between the Zn coordination in MOFs and CA active center. The biomimetic activity of MOFs was investigated by detecting the hydrolysis of para-nitrophenyl acetate, which is a model reaction used to evaluate CA activity. The biomimetic materials (e.g., CFA-1) showed good catalytic activity, and excellent reusability, and solvent and thermal stability, which is very important for practical applications. In addition, ZIF-100 and CFA-1 were used to mimic CA to convert CO₂ gas, and exhibited good efficiency on CO₂ conversion compared with those of other porous materials (e.g., MCM-41, active carbon). This biomimetic study revealed a novel CO₂ treatment method. Instead of simply using MOFs to absorb CO₂, ZIF-100 and CFA-1 were used to mimic CA for in situ CO₂ conversion, which provides a new prospect in the biological and industrial applications of MOFs.

A bio-inspired zinc finger analogue anchored in 2D hexagonal mesoporous silica for room temperature CO2activation via a hydrogenocarbonate route

A room temperature hydrogenocarbonate intermediate in CO₂activation by a carbonic anhydrase active site analog inserted in the nanopores of mesostructured porous silicas.

Cyclodextrin-based ordered rotaxane-monolayers at gold surfaces

Complexation-to-deaggregation effect of cyclodextrin was applied to achieve ordered functional monolayers on a gold surface.

Metal organic frameworks mimicking natural enzymes: a structural and functional analogy

In this review, we have portrayed the structure, synthesis and applications of a variety of biomimetic MOFs from an unprecedented angle.

Carbonic anhydrase-mimetic bolaamphiphile self-assembly for CO2 hydration and sequestration

A biomimetic catalyst was prepared through the self-assembly of a bolaamphiphilic molecule with histidine moieties for the sequestration of carbon dioxide. The histidyl bolaamphiphilic molecule bis(N-α-amidohistidine)-1,7-heptane dicarboxylate has been synthesized and self-assembled to produce analogues of the active sites of carbonic anhydrase (CA) after association with Zn(2+) ions. Spectroscopic analysis demonstrated the coordination of the Zn(2+) ions with histidine imidazole moieties, which is the core conformation of CA active sites. The Zn-associated self-assembly worked as a CA-mimetic catalyst that shows catalytic activity for CO2 hydration. Evaluation of the kinetics of using para-nitrophenylacetate revealed that the kinetic parameters of the CA-mimetic catalyst were maximized at the optimal Zn concentration and that excess Zn ions resulted in deteriorated catalytic activity. The performance of the CA-mimetic catalyst was enhanced by changing the pH value and temperature of the reaction, which implies that the hydrolysis of the substrate is the rate-determining step. The catalyst-assisted sequestration of CO2 was demonstrated by CaCO3 precipitation upon the addition of Ca(2+) ions. This study offers an easy way to prepare enzyme analogues for CO2 sequestration through the self-assembly of bolaamphiphile molecules with designer biochemical moieties.

Fabrication of high-performance facilitated transport membranes for CO2 separation

At present, liquid membranes, ion-exchange membranes and fixed carrier membranes are the three popular facilitated transport membranes for CO₂ separation. We report a method to combine their advantages and overcome their deficiencies.