Preparation and Characterization of Polyamidoamine G2.0-Hematin as a Biocatalyst for Fabricating Catecholic Gelatin Hydrogel

Tan Phuoc Ton,Le Hang Dang,Phuong Doan,Thi Yen Nhi Tran,Dinh Trung Nguyen,Kim Thi Hoang Nguyen,Ngoc Quyen Tran,Bich Tram Nguyen,Bao Huy Le,Van Toan Nguyen

doi:10.1155/2021/5563229

Abstract

In this study, we report that an enzyme-mimicking biocatalyst polyamidoamine (PAMAM) dendrimer G2.0-hematin (G2.0-He) was fabricated successfully. The chemical structure of G2.0-He was verified by 1H NMR and FT-IR spectroscopy. G2.0-He exhibited a size distribution from 11.6 ± 1.7 nm to 12.5 ± 2.9 nm and a zeta potential from 32.5 mV to 25.6 mV along with the enhancement of the hematin conjugation degree. The relative activity of G2.0-He was evaluated based on pyrogallol oxidation reactions at pH = 7 . The results showed that G2.0-He was more stable than horseradish peroxidase (HRP) enzyme in high H2O2 concentrations. The HRP-mimic ability of G2.0-He was also confirmed by the catalyzation when preparing catecholic gelatin hydrogels under mild conditions. Moreover, our results also revealed that these hydrogels performed with excellent cytocompatibility in an in vitro study and could be used as a potential scaffold for adhesion and proliferation of fibroblast cells. The obtained results indicated that G2.0-He is a suitable platform for altering the HRP enzyme in several biomedical applications.

Highlights

Hydrogels are recognized as excellent 3D matrices that can mimic cell and tissue culture environments; hydrogels have become a tremendous motivator in biomedical research fields [1,2,3,4]
The peroxidase enzyme could accelerate the oxidation of phenolic hydroxyl groups to form a chemical crosslinking, subsequently resulting in the formation of a hydrogel network at the desired time that is suitable for implantation surgeries [5, 6]
Successful synthesis of G2.0-He was verified by 1H NMR and Fourier transform infrared (FT-IR) spectroscopy

Summary

Introduction

Hydrogels are recognized as excellent 3D matrices that can mimic cell and tissue culture environments; hydrogels have become a tremendous motivator in biomedical research fields [1,2,3,4]. Because of the following requirements for tissue regeneration, namely, biocompatibility, biodegradability, and versatile applications, various injectable hydrogel systems have been introduced. The application of a peroxidase enzyme in the preparation of injectable hydrogels is suggested as an attractive technique [5]. The peroxidase enzyme could accelerate the oxidation of phenolic hydroxyl groups to form a chemical crosslinking, subsequently resulting in the formation of a hydrogel network at the desired time that is suitable for implantation surgeries [5, 6]. The change in the oxidation stage of hem groups (the active site of HRP) in the presence of an oxidant agent (H2O2) induces the formation of free radical phenolic substrates leading to the crosslinking of the aromatic ring by C-C and C-O coupling, and leading to hydrogel

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