Biotecnologia e Biomateriais

Abstrato

Shelf Life and Chemical Stability of Calcium Phosphate Coatings Applied to Poly Carbonate Urethane Substrates

Dunstan H Barnes, Ravin Jugdaosingh, Sinan Kiamil and Serena M Best

Many modern orthopaedic implants are coated with calcium phosphate to improve the host tissue response to the implants. Despite numerous studies on the dissolution properties of calcium phosphate (CaP) coatings, the coating “shelf life” (i.e. the chemical stability of these coatings prior to implantation), has not been investigated adequately, particularly for CaP coatings applied to polymeric substrates. This paper examines the chemical stability of CaP coatings that were applied to a poly carbonate urethane (PCU) substrate by an aqueous, low temperature technique. Applying a CaP coating to the PCU surface is designed to enhance the fixation between the implant and adjacent vertebrae. High temperature coating techniques are unfeasible for polymeric substrates, like PCU, because the high temperature may critically degrade the substrate. The CaP coating shelf life was assessed by using FTIR-ATR and SEM to analyze changes in CaP-coated PCU discs over time. The expected in vivo chemical stability of the CaP coating was measured by immersing CaP-coated PCU discs in cell culture media under physiological conditions. ICP-OES was used to measure the calcium and phosphorus concentrations of the immersion solution.