Preparation and characterization of novel poly (vinyl alcohol)/collagen double-network hydrogels

Hydrogels prepared by conventional methods show poor performance in many aspects. Many double network (DN) hydrogels prepared by crosslinking agents have disadvantages such as toxicity. In this work, we prepared novel DN hydrogels with fish-originated collagen (Col) and poly (vinyl alcohol) (PVA), in which self-assembly of collagen and self-crosslinking of PVA were achieved. Infrared spectra indicated the existence of double network with chemical interactions between Col and PVA. X-ray diffraction (XRD) patterns showed that characteristic peak of freeze-thaw PVA in DN hydrogel was retained. Scanning electron microscope (SEM) images before and after degradation and swelling property tests indicated that the morphology of the hydrogel was a compact meshwork, which is consistent with the high water-retention rate. The degradation rate of the DN hydrogels was controlled by the ratio of Col and PVA. Compared with a pure collagen hydrogels, the stress of DN hydrogels was greatly enhanced from 6 to 33 kPa at a strain of 40%. This study indicates that DN hydrogels prepared by Col and PVA are an ideal biomaterial for tissue engineering.