Biocompatibility and drug release kinetics of TiNbZrSn femtosecond laser-induced superhydrophilic structures

Abstract

As load-bearing components, metallic implants are frequently used for orthopedic prostheses due to their superiority over conventional ceramic and polymeric biomaterials. Metal-based orthopedic implants have been subjected to various fabrication and treatment methods to enhance their biological activities at the host site. Modifying the structure, improving the hydrophilicity, and developing controlled-release drug delivery systems can improve cellular adhesion, proliferation, osseointegration, and differentiation. Ultrafast lasers have recently attracted interest in surface engineering. Laser surface structuring permits the alteration of sample topography, the chemical makeup of the surface, and the material physical properties. This study presents the surface modification of a TiNbZrSn shape memory alloy using a femtosecond laser to produce laser-induced periodic structures with better drug release than that of a pristine sample. We also present the in vitro cell viability and biocompatibility of the alloy system. All samples structured with femtosecond laser exhibited superhydrophilic nature with 0° contact angle. In addition, the laser structured surfaces showed cell viability above 80 % and minimal cytotoxicity towards human keratinocytes. Moreover, a well-defined hydroxyapatite layer developed on the laser structured surface. In general, the laser structuring process and the induced changes on the surface in terms of roughness and oxide formation result in slower drug release (up to 10 %) compared to pristine specimens.