Thermal-responsive microgels incorporated PVA composite hydrogels: Integration of two-stage drug release and enhanced self-healing ability for chronic wound treatment

Thermal-responsive microgels constructed based on poly(ethylene glycol) methacrylates (PMO) are promising in the biomedical field owing to their biocompatibility and tunable low critical solution temperature (LCST). In this study, we prepared the composite microgels (PMO-carboxymethyl cellulose (CMC)) with enhanced thermal-responsive properties by simply mixing CMC with PMO microgels. The composite microgels exhibited increased particle size, hydrophilic performance, and temperature-dependent optical properties. The drug-loaded PMO microgels showed the ability of temperature-controlled drug release. Meanwhile, CMC modification increased drug loading capacity and reduced the burst release of the composite microgels. The microgels were further embedded in borax cross-linked poly(vinyl alcohol) (PVA) hydrogels to prepare a thermal-responsive composite hydrogels. The thermal-responsive properties of the microgels were unhindered by the surrounding hydrogel matrix. Compared with PMO microgels, the incorporation of PMO-CMC microgels led to a denser honeycomb microstructure and excellent self-healing ability. These composite hydrogels exhibited a two-stage drug release of thermal-responsive drug release from microgels and prolonged drug delivery from PVA matrix. The in vivo chronic wound model studies demonstrated that the drug-loaded PMO-CMC-PVA hydrogels contributed to a better therapeutic effect for chronic wound healing owing to their desired properties. This thermal-responsive composite hydrogels provided a promising treatment for complicated wound management and can be extended for other applications in the biomedical field