No abstract

CoS, which was prepared using a facile solvothermal method, and characterized using various analytical techniques, was demonstrated for the first time to exhibit intrinsic peroxidase-like activity.

Horseradish peroxidase (HRP) holds great potential in wastewater treatment. However, its instability in harsh environments remains a major issue. Various immobilization technologies were developed to retain enzyme stability at the cost of its effectiveness. We demonstrate that zwitterionic encapsulation of HRP retained both protein stability and activity to a large degree. In a water treatment study, encapsulating HRP into a zwitterionic nanogel resulted in a three-fold increase in the catalytic oxidation efficiency of phenol molecules. In addition, zwitterionic nanocapsules exhibited the best performance when compared with nanocapsules made from other hydrophilic polymers. These results indicated that zwitterionic HRP nanocapsules hold great potential in the decontamination of organic pollutants from wastewater.

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.

Peroxidase-like nanozymes are nanoscale materials that can closely mimic the activity of natural peroxidase for a range of oxidation reactions. Surface coating with polymer nanogels has been considered to prevent the aggregation of nanozymes. For a long time, the understanding of polymer coating has been largely limited to its stabilization effect on the nanozyme in aqueous media, while little is known about how polymer coating plays a role in interaction with substrates and primary oxidants to dictate the catalytic process. This work reported a facile sequential modification of Fe3O4 nanoparticles to polyacrylamide coated nanozymes, and as low as 112 mg/L samples with only 5 mg/L Fe3O4 could nearly quantitatively (99%) remove a library of organic dyes with either H2O2 or Na2S2O8 as primary oxidants. The catalytic results and molecular simulation provide both experimental and computational evidence that the hydrogen bonding interaction between the reactant and nanozymes is key for the high local concentration hence catalytic efficiency. We envision that this work, for the first time, provides some insights into the role of polymer coating in enhancing the catalytic activity of nanozyme apart from the well-known water dispersity effect.