Mechanical and biocompatibility properties of UHMWPE–HNT composite for joint replacement applications

Ultrahigh molecular-weight polyethylene (UHMWPE)-based composites are extensively utilized as a bearing surface in joint replacements. In the present study, due to their unique and versatile attributes halloysite nanotubes (HNTs) were used as additives in different percentages 1, 3, 5, 7 and 10 wt% to enhance the properties of UHMWPE. The effects of the weight fraction of HNT on UHMWP were investigated in terms of hardness, abrasion strength, compression strength, bulk modulus, impact resistance and biocompatibility, and the specimen showed that only a small amount of HNT (1%) optimized all the mentioned properties by 26.8, 20.77, 174.7, 351.53, 11.35 and 95%, respectively. The percentage of 5% HNT achieved the optimal content, at which the composites experienced the maximum enhancement for compression, abrasion and hardness properties. In-vitro MTT assay of UHMWPE with 1, 3 and 5% HNT nanocomposites using MG-63 cells revealed high cell viability (94.307%) after 4 days of incubation in media at concentrations of 100, 50 and 25 µg ml^–1, indicating excellent biocompatibility. These results might lay a solid basis for load bearings used in orthopaedic applications of UHMWPE-based composites.