Immediate hemorrhage control and anti-infection play important roles in the wound management. Besides, a moist environment is also beneficial for wound healing. Hydrogels are promising materials in urgent hemostasis and drug release. However, hydrogels have the disadvantage of rapid release profiles, leading to the exposure to high drug concentrations. In this study, we constructed hybrid hydrogels with rapid hemostasis and sustainable antibacterial property combining aminoethyl methacrylate hyaluronic acid (HA-AEMA) and methacrylated methoxy polyethylene glycol (mPEG-MA) hybrid hydrogels and chlorhexidine diacetate (CHX)-loaded nanogels. The CHX-loaded nanogels (CLNs) were prepared by the enzyme degradation of CHX-loaded lysine-based hydrogels. The HA-AEMA and mPEG-MA hybrid hydrogel loaded with CLNs (labeled as Gel@CLN) displayed a three-dimensional microporous structure and exhibited excellent swelling, mechanical property, and low cytotoxicity. The Gel@CLN hydrogel showed a prolonged release period of CHX over 240 h and the antibacterial property over 10 days. The hemostasis and wound-healing properties were evaluated in vivo using a mouse model. The results showed that hydrogel had the rapid hemostasis capacity and accelerated wound healing. In summary, CLN-loaded hydrogels may be excellent candidates as hemostasis and anti-infection materials for the wound dressing application.
Supramolecular hydrogels self-assembled by alpha-cyclodextrin and methoxypolyethylene glycol-poly(caprolactone)-(dodecanedioic acid)-poly(caprolactone)-methoxypolyethylene glycol (MPEG-PCL-MPEG) triblock polymers were prepared and characterized in vitro and in vivo. The sustained release of dextran-fluorescein isothiocyanate (FITC) from the hydrogels lasted for more than 1 month, which indicated that the hydrogels were promising for controlled drug delivery. ECV304 cells and marrow mesenchymal stem cells (MSC) were encapsulated and cultured in the hydrogels, during which the morphologies of the cells could be kept. The in vitro cell viability studies and the in vivo histological studies demonstrated that the hydrogels were non-cytotoxic and biocompatible, which indicated that the hydrogels prepared were promising candidates as injectable scaffolds for tissue engineering applications.
Poly(N-isopropylacrylamide-co-3-(trimethoxysilyl)propyl methacrylate)-b-poly(2-(diethylamino)ethyl methacrylate) (P(NIPAAm-co-MPMA)-b-P(DEA)) copolymer was synthesized by reversible addition−fragmentation chain transfer (RAFT) polymerization. The temperature and pH responsive schizophrenic micellization behaviors of P(NIPAAm-co-MPMA)-b-P(DEA) and the cross-linking of P(NIPAAm-co-MPMA) blocks using inorganic silica-based cross-linking strategy were investigated in detail. Transmission electron microscopy (TEM) showed that the resultant core cross-linked (CCL) and shell cross-linked (SCL) micelles displayed regular spherical shapes with different sizes in N,N′-dimethylformamide (DMF) and aqueous media. The structure changes of CCL and SCL micelles at different pHs and temperatures were characterized by 1H NMR. Optical absorption measurements showed that the lower critical solution temperatures (LCSTs) of the CCL and SCL micelles were 37.5 and 40.5 °C, respectively. In vitro drug release study showed that the drug-loaded CCL and SCL micelles displayed thermoresponsive and pH double responsive release behaviors.
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