Thermochromic Polyvinyl Alcohol-Iodine Hydrogels with Safe Threshold Temperature for Infectious Wound Healing.

Iodophor (povidone-iodine) has been widely used for antibacterial applications in the clinic. Yet, limited progress in the field of iodine-based bactericides has been achieved since the invention of iodophor. Herein, a blue polyvinyl alcohol-iodine (PAI) complex-based antibacterial hydrogel is explored as a new generation of biocompatible iodine-based bactericides. The obtained PAI hydrogel maintains laser triggered liquefaction, thermochromic, and photothermal features for highly efficient elimination of bacteria. In vitro antibacterial test reveals that the relative bacteria viabilities of Escherichia coli (E.coli) and methicillin-resistant Staphylococcus aureus (MRSA) incubated with PAI hydrogel are only 8% and 3.8%, respectively. Upon single injection of the PAI hydrogel, MRSA-infected open wounds can be efficiently healed in only 5 days, and the healing speed is further accelerated by laser irradiation due to the dynamic interaction between iodine and polyvinyl alcohol, causing up to ∼29% of wound area being closed on day 1. In addition, a safe threshold temperature of skin scald (∼45 °C) emerges for PAI hydrogels because of thermochromic properties, avoiding thermal injuries during irradiation. In addition, no observed toxicity or skin irritation is observed for the PAI hydrogel. This work expands the category of iodine-based bactericides for safe and controllable management of infected wounds.