Macroporous zwitterionic composite cryogel based on chitosan oligosaccharide for antifungal application.

Chitosan oligosaccharide (COS), a time-dependent antimicrobial carbohydrate, is found antifungal active with a short duration of action due to excessive solubility. We attempted to address this issue by employing a hydrogel as a COS carrier. In this research, macroporous zwitterionic composite cryogels composed of COS and poly(N-methacryl arginine) (PMarg) were fabricated, serving as long-term antifungal dressings. Firstly, Marg was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), H and C nuclear magnetic resonance (NMR), and high-resolution mass spectrometry (HRMS). Then, the COS/PMarg cryogels were prepared by redox initiation cryopolymerization. The macroporous morphology of the cryogels was confirmed by scanning electron microscope (SEM) with pore size varying from 20.86 to 50.87 μm. FTIR indicated that hydrogen bonding formed between COS and PMarg, and the interaction elevated thermal stability of the cryogels as evidenced by thermal-gravimetric analysis (TGA). Swelling capacity, mechanical properties, and COS release behavior of the COS/PMarg cryogels were investigated. With the release of COS, the antifouling activity of the cryogel increased. Antimicrobial tests indicated the COS/PMarg cryogel could effectively inhibit the proliferation of Candida albicans. It demonstrated that the macroporous zwitterionic COS/PMarg composite cryogel might be a potential antifungal dressing with sequential "sterilization-release" capacity.