Assessment of the Use of Hybrid Film With Titanium Deposition on AISI 316-L Stainless Steel Substrate as a Biomaterial

Abstract

Metals play a fundamental role in medicine, particularly in the replacement, stabilization, and reinforcement of human body structures, due to their excellent mechanical performance. However, the biocompatibility of these materials is a critical factor, as they must not induce adverse reactions or pathologies when in contact with bodily fluids, which could lead to implant rejection by the host organism. Among the widely used metals, AISI 316-L stainless steel (SS) stands out for its mechanical properties and lower cost but presents limitations related to corrosion in biological environments, leading to the release of nickel and chromium ions, which are harmful to the human body. A promising alternative to mitigate these effects is the use of biocompatible coatings. In this context, the present study aimed to develop and characterize different hybrid films on AISI 316-L SS substrates for medical applications. The coatings were based on the alkoxide precursors 3-(trimethoxysilylpropyl)methacrylate (MAP) and tetraethyl orthosilicate (TEOS), applied via dip-coating and followed by titanium thin film deposition through magnetron sputtering. The results indicated good interaction between the hybrid layer, the titanium thin film, and the substrate. The HF sample, composed of only one silane-based layer, exhibited the lowest surface roughness (16.7 ± 0.6 nm Ra) compared with pure AISI SS (27.3 ± 1 nm Ra), which positively influenced the contact angle, achieving a value of (69.1° ± 0.3°), promoting cell adhesion and osseointegration—key factors for the clinical success of implants. Surfaces coated with titanium for 10 and 20 min (HF_Ti10 and HF_Ti20) on AISI 316-L SS demonstrated contact angles similar to SS (83.4° ± 0.4°), indicating a hydrophilic behavior. Additionally, no cytotoxicity was observed in the coated samples compared with the control group after 14 days in lactate dehydrogenase (LDH) assays, and HF_Ti10 presented the lowest cytotoxicity. Adherent stem cells were found in all experimental groups. These findings suggest that pre-treatment with silane-based HF, followed by titanium thin film deposition, holds great potential for application in AISI 316-L SS materials in the medical field, contributing to the development of safe and effective implants.