Supramolecular Hydrogels Driven by β-Sheet Fibrillating Peptides for Enhanced Diabetic Wound Healing

Academic Background

Diabetic wound healing is a global health issue. Due to microvascular complications and immune dysfunction caused by hyperglycemia, the wound healing process in diabetic patients is often severely hindered. Traditional treatments, such as the use of collagen or growth factors, are somewhat effective but limited by the instability and rapid degradation of proteins in external environments. Therefore, developing a novel material that can stably deliver proteins and promote wound healing has become a research focus.

Supramolecular hydrogels, with their non-covalent binding properties, can preserve protein bioactivity while enhancing stability, making them an ideal platform for diabetic wound repair. This study developed a novel protein-peptide supramolecular hydrogel by assembling β-sheet fibrillating peptides (Q11) with β-tail fused recombinant proteins. The aim was to promote diabetic wound healing by enhancing protein stability and bioactivity.

Source of the Paper

This paper was co-authored by Zhao Guo, Xing Liu, and others from the School of Life Sciences at Inner Mongolia University, with Xinyu Li as the corresponding author. The paper was published on December 9, 2024, in the journal ACS Biomaterials Science & Engineering, titled “Assembly of Recombinant Proteins into β‑Sheet Fibrillating Peptide-Driven Supramolecular Hydrogels for Enhanced Diabetic Wound Healing.”

Research Process and Results

1. Assembly and Stability Study of Q11 Peptide with Fluorescent Proteins

The study first designed a Q11 peptide (QQKFKFQFEQQ) capable of forming β-sheet structures and combined it with two β-tail fused fluorescent proteins (GFP and mScarlet) to form β-GFP and β-mScarlet. Transmission electron microscopy (TEM) observations revealed that the Q11 peptide and fluorescent proteins assembled into disordered fibrous structures. Fluorescence microscopy and standard camera images showed that the Q11 peptide could drive the graded assembly of β-GFP and β-mScarlet, and the assembled hydrogels exhibited higher stability under varying pH and temperature conditions.

2. Construction of Collagen-Like Protein and Sonic Hedgehog Fusion Protein, and Hydrogel Preparation

Based on the assembly properties of the Q11 peptide, the research team further designed a collagen-like protein (CLP) fused with Sonic Hedgehog (SHH) to create a recombinant protein (CLP-SHH). Thioflavin T (ThT) staining was used to evaluate assembly efficiency, which significantly increased with the length of the CLP sequence. Ultimately, CLP3-SHH (C3SH) was selected to assemble with the Q11 peptide, forming the Q11C3SH supramolecular hydrogel. This hydrogel exhibited excellent injectability, making it suitable for wound repair applications.

3. Cytocompatibility and Bioactivity Evaluation of the Hydrogel

The research team used NIH-3T3 fibroblasts and HaCaT keratinocytes to assess the cytocompatibility of the Q11C3SH hydrogel. The results showed that 1%, 3%, and 5% concentrations of Q11, C3SH, and Q11C3SH hydrogels significantly enhanced cell viability, with the 5% Q11C3SH hydrogel showing the most significant improvement. Cell migration experiments demonstrated that 5% C3SH and Q11C3SH hydrogels significantly promoted cell migration, attributed to the critical role of the SHH protein in cell differentiation and proliferation.

4. Wound Healing Experiments in a Diabetic Mouse Model

The research team evaluated the wound healing efficacy of the Q11C3SH hydrogel using a streptozotocin (STZ)-induced diabetic mouse model. The results showed that the Q11C3SH hydrogel significantly accelerated the wound healing process in diabetic mice compared to the control group. Histological analysis revealed that wounds treated with the Q11C3SH hydrogel exhibited thicker epidermal layers and more collagen deposition, indicating enhanced tissue remodeling and regeneration.

5. Modulation of Inflammatory Response by the Hydrogel

Through immunofluorescence and Western blot analysis, the research team found that the Q11C3SH hydrogel significantly upregulated the expression of key proteins related to wound healing (such as COL-1α, CK-14, and α-SMA) while reducing the levels of inflammatory factors IL-6 and TNF-α. This suggests that the Q11C3SH hydrogel not only promotes tissue regeneration but also creates a more favorable environment for wound healing by mitigating inflammation.

Conclusion and Significance

This study successfully developed a Q11 peptide-driven supramolecular hydrogel by assembling collagen-like proteins with Sonic Hedgehog fusion proteins, significantly enhancing protein stability and bioactivity. The hydrogel demonstrated excellent wound healing effects in a diabetic mouse model, accelerating wound closure and promoting epidermal regeneration and collagen deposition. Additionally, the hydrogel improved the wound healing environment by modulating inflammatory responses.

Research Highlights

1. Innovative Assembly Strategy: The Q11 peptide-driven non-covalent assembly strategy allows proteins to maintain their native folding and bioactivity while achieving precise ratio control.
2. Multifunctional Hydrogel: The Q11C3SH hydrogel not only exhibits excellent injectability and stability but also significantly accelerates diabetic wound healing by modulating inflammation and promoting cell migration.
3. Potential Clinical Applications: This hydrogel provides a simple, cost-effective, and efficient therapeutic strategy for diabetic wound management, with broad clinical application prospects.

Other Valuable Information

The research team also explored the potential of the Q11 peptide in immune regulation, finding that it can exert anti-inflammatory effects by reducing the expression of inflammatory markers such as IL-6 and pNF-κB. This opens new avenues for the application of the Q11 peptide in treating other diseases, such as inflammatory bowel disease.

This study not only provides a novel supramolecular hydrogel material for diabetic wound repair but also offers new insights and methods for the development of protein delivery systems.