Improved mechanical and tribological properties of PAAm/PVA hydrogel-Ti6Al4V alloy configuration for cartilage repair

Abstract

Cartilage disease is one of the most common clinical conditions, decreasing the quality of life in a wide range of population. Hydrogels have been widely reported as potential cartilage repair materials, but the inadequate mechanical strength limits their further application. Inspired by the soft-on-hard structure of natural articular cartilage, we fabricated PAAm/PVA hydrogel on Ti6Al4V alloy configuration combining the excellent lubrication of hydrogel layer and good load-bearing capacity of rigid substrate. The mechanical and tribological properties of bulk PAAm/PVA hydrogel and PAAm/PVA hydrogel-Ti6Al4V alloy configuration as the function of PAAm:PVA mass ratio (wt/wt) were investigated. Meanwhile the bonding state of the PAAm/PVA hydrogel-Ti6Al4V alloy configuration was also detected. The mechanical properties are improved by incorporating PAAm in PVA hydrogel, but a higher mass ratio of PAAm:PVA results in the degradation of the mechanical properties. PAAm/PVA hydrogel with PAAm:PVA ratio of 1:1 shows a higher interfacial toughness, while PAAm/PVA hydrogel with PAAm:PVA ratio of 1:3 presents a lower friction coefficient of ~ 0.050. Collectively, the load carrying ability of the PAAm/PVA hydrogel is notably improved by the support of the titanium alloy substrate in the PAAm/PVA hydrogel-Ti6Al4V alloy configuration.