Antifracture, Antibacterial, and Anti-inflammatory Hydrogels Consisting of Silver-Embedded Curdlan Nanofibrils.

Abstract

The bacterial exopolysaccharide Curdlan has a unique collagen-like triple helical structure and immune-modulation activities. Although there have been several types of Curdlan gels reported for antibacterial or wound healing purposes, none of them exhibit favorable mechanical properties for clinically applicable wound healing materials. Herein, we present a two-step approach for preparing Ag-embedded Curdlan hydrogels that are highly soft but are very stretchable compared with common polysaccharide-based hydrogels. Ag ions were first reduced in a diluted Curdlan solution to form AgNP-decorated triple helices. Then, the aqueous solution consisting of Curdlan/Ag nanoparticles was mixed with a dimethyl sulfoxide solution consisting of a high concentration of Curdlan. This mixing triggered the conformation transformation of Curdlan random coils into triple helices, and then the helices were further packed into semicrystalline nanofibrils of ∼20 nm in diameter. Due to the presence of semicrystalline fibrils, this novel Curdlan hydrogel exhibits a fracture strain of ∼350% and fracture stress of ∼0.2 MPa at a water content of ∼97%. This nanofibril hydrogel supported the attachment, spreading, and growth of fibroblasts and effectively inhibited the growth of Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Moreover, the hydrogels downregulated NO production and proinflammatory gene expression levels in lipopolysaccharide (LPS)-stimulated macrophages but did not change the anti-inflammatory gene expression levels in IL-4-stimulated macrophages. In an animal study, these hydrogels accelerated wound healing in a bacteria-infected mice skin wound model. These results validate the further development of Curdlan/AgNPs nanofibril hydrogels in clinical wound management.

• Authors: Mengting Lin, Haiyue Long, Minting Liang, Bin Chu, Zhe Ren, Pengjun Zhou, Chaoxi Wu, Zhong Liu, Yifei Wang
• Journal: ACS applied materials & interfaces (ACS Appl Mater Interfaces) Vol. 13 Issue 31 Pg. 36747-36756 (Aug 11 2021) ISSN: 1944-8252 [Electronic] United States
• PMID: 34325510 (Publication Type: Journal Article)

Chemical References

• Anti-Bacterial Agents
• Anti-Inflammatory Agents
• Hydrogels
• beta-Glucans
• Silver
• curdlan

Topics

• Animals
• Anti-Bacterial Agents (chemistry, therapeutic use, toxicity)
• Anti-Inflammatory Agents (chemistry, therapeutic use, toxicity)
• Carbohydrate Conformation (drug effects)
• Escherichia coli (drug effects)
• Hydrogels (chemistry, therapeutic use, toxicity)
• Male
• Metal Nanoparticles (chemistry, therapeutic use, toxicity)
• Mice
• Mice, Inbred BALB C
• NIH 3T3 Cells
• Nanofibers (chemistry, therapeutic use, toxicity)
• Silver (chemistry, therapeutic use, toxicity)
• Skin (pathology)
• Staphylococcal Skin Infections (drug therapy, pathology)
• Staphylococcus aureus (drug effects)
• Tensile Strength
• Wound Healing (drug effects)
• beta-Glucans (chemistry, therapeutic use, toxicity)