Self-assembly of artificial peroxidase mimics from alternating copolymers with chromogenic and biocatalyst potentialities

Inspiring from the multiple functions and delicate architectures of natural peroxidases, we constructed an artificial peroxidase that can mimic as horseradish peroxidase (HRP). This mimicking construct was engineered by the self-assembly of alternating copolymers followed by encapsulation of hemin resulted in a functional vesicle exhibiting activity like peroxidase. The thiazole moiety present in copolymers poly(ethylene glycol)diglycidyl ether-alt-Bismuth-thiol P(PEGDGE-a-BTT) and 1,7-butadiene-diepoxide-alt-Bismuth-thiol P(BDD-a-BTT) can easily coordinate with hemin molecule. In this complex, hemin is present as a pentacoordinate ligand having an open site for substrate binding similar to the microenvironment in natural peroxidase. The as-prepared functional vesicles exhibited better stability and excellent catalytic activity in oxidizing orange II (azo dye) and phenolic compounds such as catechol and 3, 3′, 5, 5′-tetramethylbenzidine (TMB) using hydrogen peroxide (H₂O₂) as compared to HRP over a wide pH, temperature range, and substrate concentrations. Another striking feature of these functional vesicles (alternating polymer vesicles loaded with hemin) is their use as recognition systems for chromogenic substances, indicating that these vesicles can be used as new biocatalysts for specific functions.