The Effect of Various Surface Treatments of Ti6Al4V on the Growth and Osteogenic Differentiation of Adipose Tissue-Derived Stem Cells

Abstract

The physical and chemical properties of the material surface, especially its roughness and wettability, have a crucial effect on the adhesion, proliferation, and differentiation of cells. The aim of this study is to select the most appropriate surface modifications of Ti6Al4V implants for pre-colonization of the implants with adipose tissue-derived stem cells (ASCs) in order to improve their osseointegration. We compared the adhesion, growth, and osteogenic differentiation of rat ASCs on Ti6Al4V samples modified by methods commonly used for preparing clinically used titanium-based implants, namely polishing (PL), coating with diamond-like carbon (DLC), brushing (BR), anodizing (AND), and blasting (BL). The material surface roughness, measured by the Ra and Rq parameters, increased in the following order: PL < DLC ˂ BR ˂ AND ˂ BL. The water drop contact angle was in the range of 60–74°, with the exception of the DLC-coated samples, where it was only 38°. The cell number, morphology, mitochondrial activity, relative fluorescence intensity of osteogenic markers RUNX2, type 1 collagen, and osteopontin, the calcium consumption by the cells and the alkaline phosphatase activity depended on the surface roughness rather than on the surface wettability of the materials. Materials with a surface roughness of several tens of nanometers (Ra 60–70 nm), i.e., the BR and AND samples, supported a satisfactory level of cell proliferation. At the same time, they achieved the highest level of osteogenic cell differentiation. These surface modifications therefore seem to be most suitable for pre-colonization of Ti6Al4V implants with stem cells pre-differentiated toward osteoblasts, and then for implanting them into the bone tissue.

A comprehensive review on metallic implant biomaterials and their subtractive manufacturing

“…In addition, the physiochemical properties such as topography, wetting behavior, and elemental composition on the topmost layer of an implant surface basically ascertain its effectiveness in a biological setting. Thus, even slight changes in such properties are able to cause considerable variations in the reactivities of the implant as well as the cell at the point of their interaction [ 81 , 82 ]. However, the topographical features such as surface roughness are mainly responsible for the cells’ response such as osteogenic differentiation of cells, cell growth, and proliferation rates [ 82 , 83 ].…”

“…Thus, even slight changes in such properties are able to cause considerable variations in the reactivities of the implant as well as the cell at the point of their interaction [ 81 , 82 ]. However, the topographical features such as surface roughness are mainly responsible for the cells’ response such as osteogenic differentiation of cells, cell growth, and proliferation rates [ 82 , 83 ]. In this regard, cutting speed, feed rate, cutting tool pressure, and lubrication and their various levels were identified as some of the major machining factors inducing specific topographies on the machined metallic biomaterials [ 84 ].…”

A Simple Cerium Coating Strategy for Titanium Oxide Nanotubes’ Bioactivity Enhancement

“…As a bio-inert material, Ti is not able to actively interact with the surrounding environment and to favor a satisfactory cell adhesion, which are instead key points for the formation of the structural and functional direct connection between the living bone and the implant surface needed to ensure long-term stability [3]. Great efforts have been paid to improve bone-implant contact, such as changing the substrate surface topography [4,5], chemically modifying the surface layer [6,7], and coating the implant with bioactive materials [8,9]. Fabricating a TiO 2 nanotube array (TiNT) by means of direct electrochemical anodic oxidation of the titanium substrate is one of the most promising approaches.…”

A New α + β Ti-15Nb Alloy with Low Elastic Modulus: Characterization and In Vitro Evaluation on Osteogenic Phenotype

“…Stepanovska et al [ 30 ] analyzed the growth and osteogenic differentiation of mesenchymal stem cells derived from rat adipose tissue on the surface of commercial Ti-6Al-4V alloy with different surface roughness values. According to the authors, even though Al and V are considered cytotoxic, osteoblastic cells adhered to the Ti-6Al-4V alloy and proliferated well.…”