Improvements in bioactivity, blood compatibility, and wear resistance of thermally sprayed carbon nanotube reinforced hydroxyapatite-based orthopedic implants

Abstract

Titanium implants often fail due to aseptic loosening and non-hemocompatibility, necessitating costly revision surgeries. This study investigated the wear performance and biocompatibility of high-velocity oxy-fuel (HVOF) sprayed-hydroxyapatite (HA) and HA/alumina-19 wt%/carbon nanotube (CNT)− 1 wt% (HAC1) coatings. The novel heterocoagulation colloidal technique effectively dispersed CNTs, enhancing adhesion strength by ∼120 %, hardness by ∼45 %, and wear resistance by ∼32 % in simulated body fluid (SBF) and 17 % in dry conditions versus HA coatings, attributed to the low coefficient of friction (CoF) (1.16–1.48 times than HA) due to lubrication offered by peeled-off graphite layers from the CNT surface. Additionally, HAC1 implants exhibited superior apatite growth (∼52 % than HA), excellent non-hemolytic behavior (∼0.2 %), and no platelet activation, making it highly promising for orthopedic applications. © 2024 Elsevier Ltd