Functionalization of titanium with chitosan via silanation: evaluation of biological and mechanical performances.

Complications in dentistry and orthopaedic surgery are mainly induced by peri-implant bacterial infections and current implant devices do not prevent such infections. The coating of antibacterial molecules such as chitosan on its surface would give the implant bioactive properties. The major challenge of this type of coating is the attachment of chitosan to a metal substrate. In this study, we propose to investigate the functionalization of titanium with chitosan via a silanation. Firstly, the surface chemistry and mechanical properties of such coating were evaluated. We also verified if the coated chitosan retained its biocompatibility with the peri-implant cells, as well as its antibacterial properties. FTIR and Tof-SIMS analyses confirmed the presence of chitosan on the titanium surface. This coating showed great scratch resistance and was strongly adhesive to the substrate. These mechanical properties were consistent with an implantology application. The Chitosan-coated surfaces showed strong inhibition of Actinomyces naeslundii growth; they nonetheless showed a non significant inhibition against Porphyromonas gingivalis after 32 hours in liquid media. The chitosan-coating also demonstrated good biocompatibility to NIH3T3 fibroblasts. Thus this method of covalent coating provides a biocompatible material with improved bioactive properties. These results proved that covalent coating of chitosan has significant potential in biomedical device implantation

Acidic pH resistance of grafted chitosan on dental implant

International audienceOver the last decade, access to dental care has increasingly become a service requested by the population, especially in the case of dental implants. However, the major cause of implant failure is an inflammatory disease: peri-implantitis. Currently, the adhesion strength of antibacterial coatings at implant surfaces remains a problem to solve. In order to propose a functionalized implant with a resistant antibacterial coating, a novel method of chitosan immobilization at implant surface has been investigated. Functionalization of the pre-active titanium (Ti) surface was performed using triethoxysilylpropyl succinic anhydride (TESPSA) as a coupling agent which forms a stable double peptide bond with chitosan. The chitosan presence and the chemical resistibility of the coating under acid pH solutions (pH 5 and pH 3) were confirmed by FTIR-ATR and XPS analyses. Furthermore, peel test results showed high adhesive resistance of the TESPSA/chitosan coating at the substrate. Cytocompatibility was evaluated by cell morphology with confocal imaging. Images showed healthy morphology of human gingival fibroblasts (HGF-1). Finally, the reported method for chitosan immobilization on Ti surface via peptide bindings allows for the improvement of its adhesive capacities and resistibility while maintaining its cytocompatibility. Surface functionalization using the TESPSA/chitosan coupling method is noncytotoxic and stable even in drastic environments as found in oral cavity, thus making it a valuable candidate for clinical implantology applications

The effects of chitosan coated Ti.

<p>on Porphyromonas gingivalis and on Actinomyces naeslundii in liquid medium for 32 hours. Data are expressed in % of bacteria in contact with coated sample compared to the bacteria in contact with control (or percentage of bacterial inhibition). Data represent the means ± SD of three independent experiments. * p<0.01.</p

Proportion of chitosan specific fragments measured by Tof-SIMS.

<p>Proportion of chitosan specific fragments measured by Tof-SIMS.</p

FTIR-ATR spectra.

<p>(A) chitosan. (B) chitosan–coated sample.</p

Optical micrographs of scratches observed on chitosan-coated surfaces.

<p>Optical micrographs of scratches observed on chitosan-coated surfaces.</p

Diagram displaying % of resazurin reduction for uncoated and Chitosan-coated samples.

<p>Data are given after 2, 4 and 7 days of NIH3T3 fibroblasts culture. Data are presented as means ± SD.</p

Schemes displaying coating behavior under tip contact with an applied load (F).

<p>(A) the burial depth (h) is less than the thickness of the coating (e). (B) the burial depth (h) is greater than the thickness of the coating (e).</p

Optical micrograph of scratch observed on chitosan-coated surface.

<p>The image is a detail of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039367#pone-0039367-g004" target="_blank">Figure 4</a> for a applied load of 5,5 N.</p