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

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.

Preparation of injectable free‐HRP‐mediated and self‐catalyzed gelatin‐tyramine hydrogel for biomedical applications

“…Besides, the HRP enzyme was inactivated when the H 2 O 2 concentration was up to 30 mM, in agreement with previous studies. [ 26 ] Therefore, HGT has great applicability due to its high stability.…”

“…The method is based on previous studies. [15,[25][26][27] First, gelatin (Ge, 2 g, 1.36 mmol) was dissolved in 20 ml of deionized water at 40 o C. Added Tyramine (Tyr) into the gelatin solution at a 1:4 molar ratio (amine groups of Tyr and carboxylic groups of Ge). After the mixture received additions of EDC and NHS, pH was set to 5 using dilute HCl.…”

“…It can be seen that HGT has good gel-forming ability with a small concentration of H2O2 that is not enough to cause damage to cells. [26,27] Therefore, the HGT polymer system has high applicability in the use of hydrogels in medicine.…”