Experimental design of Al₂O₃/MWCNT/HDPE hybrid nanocomposites for hip joint replacement

Fracture in the hip joint is a major and quite common health issue, particularly for the elderly. The loads exploited by the lower limbs are very acute and severe; in the femur, they can be several folds higher than the whole weight of the body. Nanotechnology and nanocomposites offer great potential in biomedical applications. The organic materials are more biocompatible. Mechanical properties like strength and hardness are challenging parameters which control the selection of a joint. HDPE in its pure form has been successfully used as a prosthetic foot (external) but failed as an implant material due to limited mechanical properties. High-density polyethylene thermoplastic polymer (HDPE) and multi-walled carbon nanotubes (MWCNT)/Nano-Alumina is selected as a potential material for a biomedical implant and its mechanical properties and biocompatibility have been discussed. HDPE/MWCNT/Alumina (Al₂O₃) nanocomposites have not been explored yet for prosthetic implants. These nanocomposites were prepared in this investigation in different compositions. Prepared material has been physiochemically characterized to check the morphology and the structure. MWCNTs enhanced hardness and elastic modulus of the HDPE. Optimization of the material composition revealed that hybrid composite with structure (2.4% Al₂O₃ and 0.6% MWCNT) exhibits better mechanical properties compared to other ratios with 3% MWCNTs and 5% MWCNTs. Thermal gravimetric analysis (TGA) dedicates that the percentage of crystallization has been increased to 6% after adding MWCNT to HDPE. The moisture absorption decreased to 90% with 5% MWCNT. Experimental results of Colorimetric assay (MTT) of a normal human epithelial cell line (1- BJ1) over Al₂O₃/MWCNT@HDPE showed <20% cytotoxic activity, proving its acceptance for medical use. HDPE/MWCNT/Al₂O₃ nanocomposites emerged as a candidate material for artificial joints.