Reduction of Biofilm Infection Risks and Promotion of Osteointegration for Optimized Surfaces of Titanium Implants

Abstract

Titanium‐based implants are widely used in modern clinical practice; however, complications associated with implants due to bacterial‐induced infections arise frequently, caused mainly by staphylococci, streptococci, Pseudomonas spp. and coliform bacteria. Although increased hydrophilicity of the biomaterial surface is known to be beneficial in minimizing the biofilm, quantitative analyses between the actual implant parameters and bacterial development are scarce. Here, the results of in vitro studies of Staphylococcus aureus and Staphylococcus epidermidis proliferation on uncoated and coated titanium materials with different roughness, porosity, topology, and hydrophilicity are shown. The same materials have been tested in parallel with respect to human osteogenic and endothelial cell adhesion, proliferation, and differentiation. The experimental data processed by meta‐analysis are indicating the possibility of decreasing the biofilm formation by 80–90% for flat substrates versus untreated plasma‐sprayed porous titanium and by 65–95% for other porous titanium coatings. It is also shown that optimized surfaces would lead to 10–50% enhanced cell proliferation and differentiation versus reference porous titanium coatings. This presents an opportunity to manufacture implants with intrinsic reduced infection risk, yet without the additional use of antibacterial substances.

Titanium implants with modified surfaces: Meta-analysis of in vivo osteointegration

“…It was shown earlier by the authors [1] that some of the parameters are intrinsically linked (e.g. roughness Ra and Rz were clearly correlated).…”

“…It is difficult to make a vast number of specific surfaces with different features being independently varied to evaluate their specific effect in vivo. It was recently demonstrated in vitro to be possible to adjust titanium coating parameters to reduce bacterial adhesion and to enhance cell proliferation and differentiation at the same time vs. non-optimized plasma-sprayed Ti [1]. These data, however, might not be directly extrapolated to in vivo host conditions, as there are many other variables, most of them are beyond control (such as specific animal mobility or its health conditions).…”

“…Distinct TiH2 powder grades of different particle sizes, all supplied by Chemetall GmbH (Germany), have been used: grade type P (average particle size 8.0 ± 2.0 μm, maximal 60 μm), U (5.0 ± 1.0 μm, maximal 45 μm) and VM (1.8 ± 0.2 μm, maximal 45 μm). Different pore size and morphologies were realized by combining various particle sizes [1].…”

“…Surface and pore structure of the various coatings was analyzed as described in [1]. Surface roughness was measured by white light interferometry (Wyko NT 3300 Optical Profiler, Veeco Metrology Inc., USA).…”

“…In this work, we are rather analyzing the effect of different titanium implants and their surface parameters linked with histomorphometrical features obtained from in vivo tests, for the same materials which behavior in vitro has been recently reported [1]. The main essential feature of advanced meta-analytical methods applied to the subject of the study is in focusing on the links between the controllable input variables (material parameters) and in vivo responses, without speculating about the exact mechanisms behind these interactions.…”