Antimicrobial polyacrylic acid/tannic acid hydrogel wound dressing facilitating full-thickness skin healing

Abstract

Polyphenolic compound-modified hydrogel wound dressings with excellent wet tissue adhesion, antimicrobial properties, stretchability, and full-thickness skin healing properties are still extremely rare so far. Polyphenolic compounds such as tannic acid or dopamine can improve the antibacterial and bioadhesive properties of hydrogels, and are also polymerization inhibitors for free radical polymerization. In this study, polyacrylic acid (PAA) aqueous solution was first synthesized, and then antibacterial PAA-TA hydrogel was prepared by mixing it with tannic acid (TA) and the crosslinker 1,6-hexanediol bis(2-methyl-1-propionic acid azide) (HBMAP). This method avoids the hindrance of the phenolic hydroxyl groups in TA on acrylic acid polymerization, and we were able to obtain a series of TA hydrogels (in the range of 0–15 wt.%. We applied these PAA-TA hydrogels to wound dressings and found that they had excellent adhesion to biological tissues, and the tensile strength and elongation at break of PAA-TA hydrogels with 15 wt.%TA content were as high as 1.72 MPa and 1446.3% in tensile strength evaluation. In addition, microbiological analysis showed that wound dressings had significant antimicrobial activity against Staphylococcus aureus and Escherichia coli. In vitro wound healing experiments confirmed that the wound dressing was biocompatible and could significantly promote the healing of full-thickness skin defects in the guinea pig model. Our work describes an injectable, self-healing, antimicrobial hydrogel that may have promising clinical applications as a wound dressing material.

Keywords:

• Hydrogel
• tannic acid
• wound dressing
• self-healing
• covalent and non-covalent interwoven network structure

Acknowledgements

Authors are grateful to Dr Yunzhi Tan and Zujiang Xi for providing DSC and SEM measurement facilities at the material analysis and testing center of Three Gorges University.

Authors’ contributions

Changlin Zhou: funding acquisition, software, data curation, writing, original draft preparation. Lingmin Chen: writing – review, software, investigation, visualization, methodology. Wenyan Zhou: validation, investigation, writing – review. Ruitao Zhang: review. Lei Wang: writing – review. Chen Yang: editing, conceptualization, methodology, writing – review.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

Authors thank Open Funds of Hubei Three Gorges Laboratory (NO. SC211002), the Natural Science Foundation of Hubei Province (NO. 2021CFB605) and the 111 Project of Hubei Province (NO. 2018-19-1) for financial support.