# Design and Biological Evaluation of a Gelatin/Recombinant Type III Collagen/CMC Composite Hydrogel for Wound Healing

## TL;DR

A new hydrogel combining gelatin, collagen, and CMC was developed to improve wound healing by supporting cell migration and blood vessel growth.

## Contribution

A composite hydrogel with tunable properties was developed to enhance wound healing through optimized biomaterial integration.

## Key findings

- The hydrogel's mechanical modulus and degradation could be controlled by adjusting the rColIII/CMC ratio.
- The optimized formulation increased cell migration and promoted a pro-regenerative macrophage phenotype.
- In diabetic wound models, the hydrogel accelerated wound closure and improved tissue quality.

## Abstract

Effective chronic skin wound healing remains challenging due to excessive inflammation, insufficient vascular support, and impaired extracellular matrix remodeling. By rationally designing and integrating complementary biomaterials, it is possible to synergistically tailor physicochemical properties and biological performance for tissue repair and regeneration. In this study, a gelatin-based composite hydrogel incorporating recombinant type III collagen (rColIII) and carboxymethyl cellulose (CMC) was developed via EDC/NHS-mediated crosslinking and evaluated for wound repair. By tuning the rColIII/CMC ratio, the hydrogel mechanical modulus (G′) increased from ~1.2 kPa to ~2.6 kPa, and enzymatic degradation could be modulated, as reflected by changes in the remaining material mass. The optimized Gel/rCol/CMC-1 formulation supported 3T3 cell migration (1.8-fold increase at 24 h) and promoted a pro-regenerative (M2-like) macrophage phenotype in vitro. In a full-thickness diabetic wound model, Gel/rCol/CMC-1 accelerated wound closure (82.3 ± 4.7% vs. 56.9 ± 5.1% at day 14) and enhanced tissue quality, evidenced by more organized collagen deposition and increased CD31+/α-SMA+ vessel density. These results demonstrate that formulation-driven tuning of gelatin/rColIII/CMC matrices creates a supportive microenvironment for coordinated wound repair, highlighting their potential as regenerative hydrogel dressings for difficult-to-heal wounds.