Journal of Nanomedicine & Nanotechnology

Abstract

Functionalization of Nanostructured TiO2 Surfaces with Electrodeposited Strontium Doped Calcium Phosphate and Evaluation of BSA Adsorption for Dental Implant Design

Issa S, Azevedo C, Pires R, Cenedese P and Dubot P

The aim of this work is to study the initial adsorption steps of strontium doped calcium phosphate compounds onto a nanostructured TiO2 surface and to evaluate its influence on the adsorption of Bovine Serum Albumin (BSA). TiO2 nanotubes (nT-TiO2) arrays were fabricated by anodic oxidation of titanium samples in a fluoride-based solution. Calcium phosphate (CaP) and Strontium doped calcium phosphate (Sr.CaP) have been deposited using pulsed electrodeposition process. Surface nanostructuration (nT-TiO2) allows the creation of specific reactive sites on TiO2 surfaces which are not existed on non-nanostructured ones. Scanning Electron Microscopy (SEM) reveals that the most reactive sites on these nanostructured surfaces for CaP adsorption were the nanotube edges where the CaP deposits mostly growth. Due its positive bioactive properties in inducing bone formation on Ti alloys implants, partial substitution of Ca2+ by Sr2+ was studied. Results obtained by X-Ray Photoemission Spectroscopy (XPS) and Infrared Spectroscopy (IR) in reflection-absorption mode revealed that for pure CaP coating, the deposited CaP phase was amorphous apatitelike compound (ACP). In the case of Sr2+ doped CaP, we observed the formation of a more ordered Ca1-xSrxHPO4 compound similar to Dicalcium Phosphate Anhydrous (DCPA; CaHPO4) or Dicalcium phosphate dihydrate (DCPD; CaHPO4.2H2O) which is more resorbable than ACP or hydroxyapatite (HAP). BSA adsorption on these functionalized surfaces has been realized at neutral, acidic and basic pH values. Kinetic and conformational analyses have been done using IR spectroscopy and revealed a remarkable influence of surface functionalization on the protein conformation during the adsorption process.