Smart hydrogel with rapid self-healing and controlled release attributes for biomedical applications

Abstract

A novel shear-thinning cross-linked hydrogel (HG) of polyvinyl alcohol and guar gum has been developed. The HG exhibited a fast self-healing ability within 60 s to bear deformation and possessed excellent stretchability and thermoresponsive properties. The HG was loaded with AgNPs using the in-situ cross-linking method to form the HG composite (HGC). SEM study revealed that the surface of the HG transformed from a dense and non-porous structure to an unordered and porous structure in the HGC suitable for immobilization of the AgNPs. X-ray photoelectron spectroscopy deconvolution study confirmed the presence of silver in the HGC. The cumulative release of silver nanoparticles from HGC was investigated and found that about 15% of the loaded Ag is released over five days. Ag release data fitment to various mathematical models specified that the Ag release profile is explained best by the Korsmeyer–Peppas model which revealed that the release of Ag from the HG was mainly administered by diffusion. The diffusion constant was calculated to be 5.1 cm2 s−1, indicative of an excellent controlled release system. The synthesized HGC can exhibit antibacterial activity on both gram-positive and gram-negative bacteria. The release mechanism and effective antibacterial activity support the synergic structure-property correlation of the HG and HGC.