Ryota Goto

This study aims to establish a functional hydrogelation system that integrates both dynamic and static properties without the use of additives. Given the increasing demand for biocompatible and mechanically tunable hydrogels, a hydrogelation strategy to prepare hydrogels from a precursor containing 3‐aminophenylboronic acid (3APBA)‐grafted alginate (Alg‐3APBA) and horseradish peroxidase (HRP) via a H ₂ O ₂ ‐triggered cascade reaction involving deboronation and subsequent HRP‐mediated crosslinking was developed. Because of the dynamic bonds between 3APBA and 1,2‐diol moieties in the alginate backbone, the obtained Alg‐3APBA precursor exhibited pH‐dependent viscoelasticity. At pH 7.4 and 8.0, in the presence of HRP, the Alg‐3APBA precursor formed phenol–phenol crosslinked hydrogels through the H ₂ O ₂ ‐triggered and HRP‐mediated reaction. Furthermore, HepG2 cells were viable and proliferated in the resulting Alg‐3APBA hydrogels prepared with H ₂ O ₂ (<10 m m ) without severe cytotoxicity. These findings highlight the potential of this dynamic‐to‐static transition hydrogelation approach as a cytocompatible and modular platform for future biofunctional materials.

In the field of tissue engineering, fibroblast growth factor-2 (FGF-2) effectively regenerates damaged tissue and restores its biological function. However, FGF-2 readily diffuses and degrades under physiological conditions. Therefore, methods for the sustained and localized delivery of FGF-2 are needed. Drug delivery systems using hydrogels as carriers have attracted significant interest. Injectable hydrogels with an affinity for FGF-2 are candidates for FGF-2 delivery systems. In this study, we fabricated a hydrogel from phenol-grafted alginate sulfate (AlgS-Ph) and investigated its application to the delivery of FGF-2. The hydrogel was prepared under mild conditions via horseradish peroxidase (HRP)-mediated cross-linking. Surface plasmon resonance (SPR) measurements show that the AlgS-Ph hydrogel has an affinity for FGF-2 in accordance with its degree of sulfation. Conditions for the preparation of the AlgS-Ph hydrogel, including HRP and H₂O₂ concentrations, are optimized so that the hydrogel can be used as an injectable drug carrier. The hydrogel shows no cytotoxicity when using 10T1/2 cells as a model cell line. The angiogenesis assay shows that FGF-2 released from the AlgS-Ph hydrogel promotes the formation of blood vessels. These results indicate that the AlgS-Ph hydrogel is a suitable candidate for the FGF-2 carrier.