Mechanical and antibacterial properties of tannic acid-encapsulated carboxymethyl chitosan/polyvinyl alcohol hydrogels

The objective of this study was to develop an effective, potential wound dressing, which was constructed with a composite hydrogel of poly(vinyl alcohol) (PVA), carboxymethyl chitosan (CMC) and tannic acid (TA) by cryogenic treatment and freeze-drying method. The as-prepared TA-crosslinked PVA/CMC hydrogels exhibited interconnected pore structure with the mean pore size of roughly 3.7 μm. We found that the compressive strength and stiffness of composite hydrogel increased when the TA component was introduced. However, the PVA/CMC-TA hydrogel possessed obviously lower swell property than that of the TA-free PVA/CMC hydrogel. We also found that the TA addition significantly improved the antibacterial capacity of the as-prepared hydrogel. Moreover, the inhibition zone test showed that the antibacterial activity of PVA/CMC-TA against S. aureus bacteria was greater than that against E. coli. The biological results indicated that the PVA/CMC-TA hydrogel exhibited good cytocompatibility to natural human dermal fibroblasts. In summary, our PVA/CMC-TA composite hydrogel exhibited promising mechanical and antibacterial properties, which showed great potential application as wound healing materials.