Biocompatibility of calcium and phosphorus doped diamond-like carbon thin films synthesized by plasma immersion ion implantation and deposition

Abstract

Diamond-like carbon has superior mechanical and chemical properties and has been widely studied as coatings in the optics, magnetic media, semiconductor and biomedical industry. In order to enhance the properties and performance of the materials, elemental doping and multi-layer deposition have been proposed. In cardiovascular biomedical applications such as artificial heart valves, low-temperature isotropic pyrolytic carbon (LTIC) is the most widely used material, but its blood compatibility is still not adequate. Diamond-like carbon (DLC) is a potential substitute due to its good biocompatibility and mechanical properties. In addition, the blood compatibility may be further enhanced by introducing some biologically friendly elements. In this work, calcium and phosphorus doped DLC films were fabricated by plasma immersion ion implantation and deposition (PIII and D). The structure and biological properties were assessed using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), contact angle measurement, and platelet adhesion test. Reduced platelet adhesion was obtained from the calcium or phosphorus doped DLC compared to LTIC, suggesting that doping DLC with calcium or phosphorus enhances its surface blood compatibility.