Light-Degradable Nanocomposite Hydrogels for Antibacterial Wound Dressing Applications

Bacterial infections in skin injuries can lead to life-threatening human diseases if not treated appropriately. Wound dressings can function as a barrier that can cover the infected sites and inhibit further bacterial infection, thus promoting wound healing processes. In recent years, hydrogel-based materials have emerged as ideal candidates for wound dressing applications due to their biochemical and mechanical similarity to human tissues, high biocompatibility, ability to conform to irregular wound surfaces, and their capability to encapsulate a variety of antibacterial agents. Nanocomposite hydrogels, on the other hand, possess novel nanostructures and/or incorporate nanomaterials into the hydrogel matrix to afford interesting properties such as enhanced mechanical strength and unique drug release profiles.<br/><br/>However, there are still many limitations associated with current hydrogel-based wound dressings, such as the on-demand release of antibacterial agents and triggered degradation. Therefore, the focus of my research project is to address these limitations by developing a light-degradable nanocomposite hydrogel that can achieve both of these goals using light (365 nm) as the single stimulus.<br/><br/>The approach we are taking involves incorporating triclosan-loaded, poly(<i>N</i>-isopropylacrylamide)-based nanogels (TCS-NGs) into a light-degradable poly(ethylene glycol)-based hydrogel matrix via a simple physical entrapment method. Upon exposure to 365 nm light, the hydrogel matrix can rapidly degrade, which subsequently releases the entrapped TCS-NGs into the surrounding environment.<br/><br/>Our results have first demonstrated that TCS-NGs possessed potent antibacterial activities. Moreover, TCS-NGs could be entrapped in light-degradable hydrogel matrix with high encapsulation efficiency. Upon exposure to light (365 nm), TCS-NGs can be released from light-degradable nanocomposite hydrogels, which still possess remarkable antibacterial efficacy in terms of inhibiting the growth of <i>Staphylococcus aureus </i>both in solution and on bacteria-infected porcine skins. Next, based on Alamar Blue assay on human dermal fibroblasts, each component of the nanocomposite hydrogel exhibited excellent biocompatibility and would not cause significant cytotoxicity. Finally, we showed that the nanocomposite hydrogel can be rapidly degraded by exposure of light, and the extent of degradation was dependent on exposure time. The results here indicate that the fabricated light-degradable nanocomposite hydrogels could serve as novel materials for antibacterial wound dressing applications.