Semi-degradable porous poly (vinyl alcohol) hydrogel scaffold for cartilage repair: Evaluation of the initial and cell-cultured tribological properties

Tissue engineering for articular cartilage repair has shown success in ensuring the integration of neocartilage with surrounding tissue, but the rapid restoration of biomechanical and biotribological functions remains a significant challenge. Poly (vinyl alcohol) (PVA) hydrogel is regarded as a potential articular cartilage replacement for its fair mechanical strength and low surface friction, while its lack of bioactivity limits its utility. Combining the advantages of tissue engineering materials and PVA hydrogel, we developed a semi-degradable porous PVA hydrogel through addition of ploy (lactic-co-glycolic acid) (PLGA) microspheres and salt-leaching technique. Friction coefficient, continuous friction tested by a ball-plate tribometer and worn surface observed by Environmental Scanning Electron Microscopy (ESEM) were characterized for scaffolds prepared with variable porogen and PLGA content. Scaffolds cultured with rabbit chondrocytes for 4 weeks were also studied. The results showed that friction coefficient increased with a rise in porogen content, while it firstly increased and then decreased with increasing PLGA content. Similar results were obtained from cell-cultured scaffolds. In continuous friction test and worn morphology characterization, samples were more prone to be damaged with an increase in porogen and PLGA content. However, wear resistance was obviously improved for all scaffolds after 4 weeks of culture, though friction coefficient went up to a certain extent.