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

Abstract

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.

A NIR-II light-modulated injectable self-healing hydrogel for synergistic photothermal/chemodynamic/chemo-therapy of melanoma and wound healing promotion

“…The GG@PANI(Fe)-borax has interesting thermal- and pH-responsive reversible gel–sol transition properties. 50 These prepared GG@PANI(Fe)-borax hydrogels with different GG@PANI(Fe) concentrations were heated at specific temperatures for 15 minutes, and the gel–sol phase transition of G1, G2 and G3 appeared at 48, 50 and 55 °C by the inverting-vial method, respectively (Fig. S10, ESI†).…”

When Iodine Meets Starch: On-Demand Generation of Photothermal Hydrogels for Mild-Temperature Photothermal–Chemo Disinfection

“…It is well known that starch can have an obvious color reaction with iodine, and the complex has an excellent photothermal effect, making it a potential photothermal therapeutic agent . Clearly, with increasing iodine content, the color became darker in the starch solution (Figure S10).…”

“…It is well known that starch can have an obvious color reaction with iodine, and the complex has an excellent photothermal effect, making it a potential photothermal therapeutic agent. 35 Clearly, with increasing iodine content, the color became darker in the starch solution (Figure S10). Therefore, optimizing the content of I 2 @ZIF-8 NPs in the composite hydrogel was an effective method to control the temperature of photothermal disinfection.…”

Photothermal Hydrogels for Promoting Infected Wound Healing

“…While ensuring safety, the utilization of continuous release of iodine and heat combined treatment can effectively promote the healing of infected wounds. [83]…”