Hydroxyapatite Coatings on Polymers Using a Custom Low-Energy Plasma Spray System

The use of polymers in modern orthopedics and tissue engineering represents a big opportunity to overcome the current challenges facing metallic implant technologies, such as the release of toxic metallic ions and particles, as well as the lack of isoelastic property. Furthermore, it is widely sought that these kinds of medical devices support bone ingrowth and enhance osseointegration. Therefore, implants can be coated with bioactive materials such as hydroxyapatite (HAp) by means of atmospheric plasma spray (APS), which is the most widely used for coating implants with materials of high capacity for osseointegration. So far, APS has been primarily applied to metallic substrates, and only a few studies are available on polymeric and composite materials. Consequently, the aim of this paper was to apply HAp coatings on polyetheretherketone (PEEK) substrates-a polymer commonly used for orthopedics implants-using a custom designed low-energy plasma spray (LEPS) system equipped with a built in-house dc torch. Due to the lower enthalpy in the LEPS system, it is expected that it will not degrade the shape or surface condition of the polymers during the process, and still achieve enough energy to properly melt the HAp powder particles. Observation of the as-coated surfaces by scanning electron microscopy shows that a successful deposition with very good coverage was achieved on the PEEK substrates.