Surface modification of CNT reinforced UHMWPE composite for sustained drug delivery

Abstract

Implant associated infection in orthopedic implants remains a serious clinical snag during the healing process. It is burden for patients in terms of health and monetary consequences. As a solution to this problem, the present study modified the surface of an UHMWPE acetabular cup liner and loaded drug therein for in-situ release. But, modification of the surface often causes deterioration of mechanical properties of the cup liner. Therefore, CNTs are reinforced with UHMWPE to enhance the initial mechanical property of the matrix. A modified solvent based etching and lyophilization technique is used to engineer thin porous surface layer on CNT reinforced UHMWPE composite. Gentamicin loaded chitosan is impregnated on porous surface through impregnation chamber by applying vacuum and pressure. Modified sample have shown impressive gentamicin release up to 492 h and had proven the efficacy of drug release to eradicate the bacteria around the sample. Besides, modified surfaces of the CNT composite have shown reduction in friction coefficient and specific wear rate by 36% and 20%, respectively, as compared to UHMWPE. This was attributed due to improved mechanical properties of CNTs and their self-lubricating mechanism. Even after drug release, the mechanical and tribological properties of CNT-UHMWPE composite are much better than UHMWPE. Positive in-vitro cytocompatibility results are also encouraging towards its intended application.