Preparation of a novel sodium alginate/polyvinyl formal composite with a double crosslinking interpenetrating network for multifunctional biomedical application

In recent years, porous materials with good absorbent capacity, mechanical properties and biocompatibility, has gradually become a research focus in the biomedical fields. In this study, a novel double crosslinking sodium alginate (SA)/polyvinyl formal (PVF) composite with interpenetrating polymer network (IPN) structure was developed. The composite was prepared through the blending of a PVA gel with SA, and then the obtained mixture was crosslinked by formaldehyde (HCHO) and calcium ion (Ca2+). The foamed composite formed by this process is hydrophilic and has a continuous porous structure. The chemical structure, micromorphology, mechanical and thermal properties, water absorbing capability and hydroexpansivity of the SA/PVF composites changed with the different proportion and distribution of SA. The formation of this special structure dramatically improved the thermal and mechanical properties as well as hydroexpansivity of the composites. Besides, SA/PVF composites were good for cell attachment and normal proliferation, which was revealed by CCK-8 assays and fluorescence microscopy on rat bone marrow derived mesenchymal stem cells (MSCs). The composite has broad application prospects and will be a promising candidate for biomedical applications, such as medical sponges, scaffolds for tissue engineering, surgical filling sponges, wound dressings and so on.