Enhancing the peroxidase-mimicking activity of hemin by covalent immobilization in polymer nanogels

Abstract

A polymeric nanozyme that can closely mimic peroxidase is presented. The coordination between pendant hemins and primary amines together with the synergistic interactions between substrates and nanogels contribute to the enhanced catalytic activity.

Hemin‐Doped, Ionically Crosslinked Silicone Elastomers with Peroxidase‐Like Reactivity

“…[ 39–41 ] Synthetic peroxidases utilizing simple aliphatic or aromatic amines exhibit similar behavior. [ 21,22,38,39 ]…”

“…Previous work to immobilize hemin in polymers has logically focused on the exploitation of water compatible/swellable polymers. In addition to hydrogels created from acrylamides that required modification of hemin, [22] there is the key precedent work of Wang et al that simply used ionic bonds to lock the hemin in place. [21] These strategies both achieved the desired goal of immobilized peroxidase activity.…”

“…[39][40][41] Synthetic peroxidases utilizing simple aliphatic or aromatic amines exhibit similar behavior. [21,22,38,39] In the silicone systems, amines present in the elastomers are thus likely playing three critical roles, providing ionic crosslinking interactions, facilitating ingress of H 2 O 2 and TMB and acting as axial ligands for hemin. H-E-NN elastomers containing 1:1 ratio have theoretically only enough primary amines to titrate the carboxylic acids and therefore the number of hemin molecules containing coordinated amines is anticipated…”

“…An alternative to surface immobilized enzymes is the development of hemin‐polymer materials that serve as artificial enzymes. [ 21,22 ] These materials can be advantageous over supported enzymes when, as is normally the case, they use simple synthetic protocols and, after production, more closely mimic the protein environment of the native enzyme in its normal environment.…”

Probing secondary coordination sphere interactions within porphyrin-cored polymer nanoparticles

“…Porphyrin has previously been incorporated into several polymeric systems. 19 Recently polymeric porphyrin systems have shown viability as peroxidase enzyme mimics 20 and potential antitumor agents. 21 Of particular relevance to this study is a series of tetra-functionalized iron porphyrin cored star polymers (PCSPs) designed and synthesized by Rodriguez and coworkers, amenable to post polymerization modification to form nanoparticles (PCNPs).…”