抄録
In this study, influence of phospholipid and protein constituents on friction and wear behavior of artificial hydrogel cartilage was investigated. A sliding pair of a spherical specimen of poly(vinyl alcohol)(PVA) hydrogel and a flat specimen of PVA hydrogel was tested in reciprocating friction test. Dipalmitoylphosphatidylcholine (DPPC) was selected as phospholipid constituent and was dispersed in saline as liposome. Fluorescent-labeled albumin and γ-globulin were used as protein constituents in lubricants at high concentration such as 1.4wt%. After reciprocating friction test, the boundary film formed on the surface of PVA hydrogel and the worn surface of PVA hydrogel were observed by using fluorescent microscope and confocal laser scanning microscope, respectively. When only albumin or γ-globulin was added to lubricant, adhesive wear pattern was significantly observed and large breaking-off of surface structure of PVA hydrogel occurred Lubricants that contain proteins and 0.01 wt% DPPC showed reduction of friction and suppression of large breaking-off of surface structure of PVA hydrogel. Under coexistence of protein and 0.02wt% DPPC, friction increased compared to that of in lubricants that contain 0.01wt% DPPC and wear patterns were almost the same as those in lubricants that contain only proteins. Therefore, not only concentration but also relative ratio of proteins and phospholipids are important factors to function those as excellent boundary lubricant for PVA hydrogel.
