Fast-Swelling Tamarind Xyloglucan/PVA Hydrogels with Interconnected Macroporous Structures for Biomedical Applications

This work demonstrates the preparation of fast-swelling hydrogels based on poly(vinyl alcohol) (PVA) and tamarind xyloglucan (XG), utilizing freeze-drying to achieve an interconnected macroporous structure. Although XG is non-toxic and abundant, it has poor mechanical properties. Therefore, XG was mixed with PVA and crosslinked with citric acid (CA). Without XG, the crosslinked PVA sample contained partially aligned channels several hundred microns wide. The addition of XG (25% w/w) reduced the structural order of the hydrogels. However, the addition of XG improved the swelling ratio from 308 ± 19% in crosslinked PVA to 533.33% in crosslinked PVA/XG. XG also increased the porosity, as the porosity of the crosslinked PVA, XG, and PVA/XG samples was 56.09 ± 2.79%, 68.99 ± 2.06%, and 66.49 ± 1.62%, respectively. Resistance to compression was decreased by the incorporation of XG but was increased by CA crosslinking. The determination of the gel fraction revealed that CA crosslinking was more effective for the PVA component than the XG component. The swelling of all hydrogels was very rapid, reaching equilibrium within 10 s, due to the interconnected macroporous structure that allowed for capillary action. In conclusion, the prepared hydrogels are non-cytotoxic and well suited for biomedical applications such as drug delivery, wound dressings, and hygienic products.