# Poly(ethylene glycol)-graft-Hyaluronic Acid Hydrogels for Angiogenesis

## TL;DR

This study creates a new type of hydrogel that can slowly release a growth factor to help blood vessels grow, which is useful for tissue repair.

## Contribution

The novel contribution is the development of PEG-grafted hyaluronic acid hydrogels with controlled release of bFGF for angiogenesis.

## Key findings

- PEG60-graft-HA hydrogel showed higher swelling and faster degradation.
- PEG60-graft-HA hydrogel enabled sustained release of bFGF in vitro.
- PEG60-graft-HA significantly promoted angiogenesis in vivo.

## Abstract

Hyaluronic acid (HA) hydrogels are promising biomaterials for tissue engineering and drug delivery due to their biocompatibility and biodegradability. The objective of this study was to develop a novel HA-based hydrogel for the controlled release of basic fibroblast growth factor (bFGF) to promote angiogenesis. A series of PEG-grafted HA hydrogels with varying PEG grafting ratios were synthesized and characterized. We evaluated their physicochemical properties, including swelling ratio, cross-linking density, and enzymatic degradation behavior, and assessed their ability to control bFGF release and induce angiogenesis in a mouse model. The results showed that the PEG-grafting ratio significantly affected the gel properties. Notably, the PEG60-graft-HA hydrogel exhibited a higher swelling ratio and more rapid degradation, suggesting a non-uniform and highly porous structure. In vitro release studies confirmed that while PEG5-graft-HA and PEG15-graft-HA gels showed burst release, the PEG60-graft-HA hydrogel demonstrated sustained release of bFGF over time. Furthermore, in vivo experiments revealed a significant increase in angiogenesis with the PEG60-graft-HA hydrogel, likely due to the prolonged release of active bFGF. These findings suggest that PEG-grafted HA hydrogels, particularly those with a higher PEG grafting ratio, are promising biomaterials for the controlled release of growth factors and applications in tissue regeneration.