Abstract: Two-layer integrative hydrogels were prepared as biomimetic articular cartilage replacement materials through ultrasonic dispersion, heat-high-pressure, freeze/thawed and radiation technique. The effects of PVP mass fraction and irradiation dose on the gel content, crystallinity structures and elastic compress modulus were investigated. The microstructures of the two-layer integrative hydrogels were also characterized. It was found that the gel content increased with the increase of PVP mass fraction(0—40%) and irradiation dose(0—60 kGy). The crystallinity of PVP-PVA composite hydrogel is the highest under 10 kGy irradiation dose and 20%PVP. Two-layer integrative hydrogel with 20% PVP under 20 kGy irradiation dose showed the highest elastic compress modulus. SEM results show that the surface structures of PVP-PVA composite hydrogels were improved with increasing the PVP mass fraction. SEM results also indicate that the integrative hydrogel showed a good compatibility between top-layer and underlayer. Based on the above results, the two-layer integrative hydrogel showed a promoting prospect as biomimetic cartilage replacement material.

Key words: Cartilage, Hydrogel, Polyvinyl alcohol(PVA), Polyvinyl pyrrolidone(PVP)