Bioperformance analysis of parylene C coating for implanted nickel titanium alloy

This study systematically conducted a bioperformance analysis of parylene C coating on implanted nickel titanium (NiTi) alloy. The NiTi alloy samples with parylene C coating were used to test film quality, interaction between the test piece and blood compatibility, biocompatibility, and antiadhesion, which was simulated in vitro. These samples were prepared with 1-, 5-, and 10-μm-thick parylene C film coatings with and without electropolishing. The test methodology followed ASTM F1147−05 for interfacial binding strength for the parylene C film, ISO 10993−4 for blood compatibility, and ISO 10993−5 for biocompatibility. Compared with the electropolishing treatment, cell viability of the parylene C coating had a positive effect on the cell proliferation test. In conclusion, parylene C coating on the NiTi alloy has a smooth surface with low friction coefficient as well as high blood compatibility and biocompatibility; thus, this structure meets the requirements for implantable medical device application, such as that of cardiovascular stents.