Lan Guanhua,Zhu Suping,Chen Dong,Zhang Hua,Zou Lijin,Zeng Yuanlin
Polyzwitterionic hydrogels as skin wound dressings have been extensively studied owing to their superior antibacterial properties and skin adhesiveness, but their practical applications still suffer from a low adhesion strength and a high swelling ratio, which hinder the application of hydrogel for cutaneous healing. Here, we developed a novel biocompatible poly[2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (PolySBMA) composite hydrogel with high stretchability, low swelling, strong skin adhesiveness, and antibacterial effect for enhancing wound healing. Naturally rigid polymers including quaternized chitosan methacrylate (QCSMA) and gelatin methacrylate (GelMA) are used as bioactive cross-linkers to endow PolySBMA/QCSMA/GelMA (SQG) hydrogel with a low swelling ratio and high bioactivity. The optimized hydrogel has excellent mechanical flexibility, with the ultimate tensile strength, tensile strain, modulus, and toughness of up to 344.5 kPa, 364%, 14.7 kPa, and 33.4 kJ m−3, respectively. The adhesiveness of the hydrogel to the skin tissue is as high as 38.2 kPa, which is critical for stopping the bleeding from the wound. The synergistic contributions from the PolySBMA and QCSMA endow hydrogel with good antibacterial properties against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Moreover, the natural polymer cross-linked polyzwitterionic hydrogel shows good cell activity, hemocompatibility, and histocompatibility. The in vivo full-thickness skin defect model demonstrates that the SQG hydrogel efficiently improves the granulation tissue formation and collagen deposition. In summary, such superiorly skin-adhesive antibacterial biocompatible hydrogel with controllable flexibility and swelling holds great promise as wound dressings for acute wounds.
Jiru Miao,Xiang Wu,Yue Fang,Mingzhu Zeng,Zhimao Huang,Mi Ouyang,Rong Wang
Catheter-associated urinary tract infections are one of the most common hospital-acquired infections. Encrustation formation results from infection of urease-producing bacteria and further complicates the situation. A typical sign of the initial onset of encrustation formation is the alkalization of the urine (pH up to 9–10). However, effective antibacterial strategies with high antimicrobial loading efficiency and pH-responsiveness of antimicrobial release are still lacking. In this study, we developed a poly(sulfobetaine methacrylate)-tannic acid (polySBMA-TA) hydrogel coating, which served as a universal, efficient, and responsive carrier for antimicrobials on urinary catheters. Common antimicrobials, including poly(vinylpyrrolidone)-iodine, copper ions, and nitrofurazone were loaded into the polySBMA-TA coating in high efficiency (several fold higher than that of the polySBMA coating), via the formation of multiple non-covalent interactions between the antimicrobials and hydrogel coating. The hydrogel coatings maintained good antibacterial properties under neutral conditions. More importantly, the pH-responsive release of antibacterial agents under alkaline conditions further enhanced the antibacterial activity of the coatings, which was advantageous for killing the urease-producing bacteria and preventing encrustation. In vitro and in vivo tests confirmed that the hydrogel coating has good biocompatibility, and could effectively inhibit bacterial colonization and encrustation formation. This study offers new opportunities for the utilization of a simple and universal antimicrobial-loaded hydrogel coating with smart pH-responsive properties to combat bacterial colonization and encrustation formation in urinary catheters.
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