Classification of DLC films for cell proliferation based on optical constants

• Published in: Diamond and related materials 2021-03, Vol.113, p.108266, Article 108266
• Main Authors: Kanasugi, Kazuya, Ohgoe, Yasuharu, Hiratsuka, Masanori, Nakamori, Hideki, Homma, Akihiko, Hirakuri, Kenji
• Format: Article
• Language: English
• Subjects: Addition polymerization; Austenitic stainless steels; Biomedical materials; Cell growth; Cell proliferation; Chemical vapor deposition; Classification; Coefficients; Diamond-like carbon; Diamond-like carbon films; Optical constants; Optical properties; Photoelectrons; Physical vapor deposition; Plasma processing; Refractivity
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2021.108266

Nine types of diamond-like carbon (DLC) films were prepared on 316L stainless steel by physical vapor deposition and chemical vapor deposition under different plasma processing conditions. The refractive index and extinction coefficient of the DLC films were evaluated with a spectroscopic ellipsometer. The DLC samples were classified into 4 types of films: a-C, a-C:H, polymer-like, and graphite-like types. In addition, the surface functions of the DLC films were analyzed by X-ray photoelectron spectroscopy and cell culture. DLC films on which high levels of cell proliferation were observed had relative high extinction coefficients and CO bond ratios. The extinction coefficient was related to cell proliferation on the DLC films and depended on the film structure and deposition methods. Using optical properties, such as the extinction coefficient, it is possible to distinguish various types of DLC films on which cells can be grown as a biointerface. [Display omitted] •Nine types of DLC films were prepared on 316L stainless steel.•The DLC films were classified based on refractive index and extinction coefficient.•CO bond ratios of the DLC films were depended on their extinction coefficients.•The extinction coefficients were shown cell proliferation level of the DLC films.