Sol-gel spray and electrophoretic deposition techniques to enhance bioactive and antibacterial response of titanium implants

TUBA AYDEMIR; BALLARRE, JOSEFINA; ALDO BOCCACCINI; LILIANA LIVERANI

Split

Simposio; 3. 7th Regional Symposium on Electrochemisty of South-East Europe; 2019

Compared to stainless steel 316L, titanium and its alloys generally proves a better tolerance for stress loading and fatigue as for permanent implant materials [1]. Cemented and cementless prosthesis are used in orthopaedic surgery and there is a vast discussion about advantages and disadvantages related with the loos of healthy bone tissue and use of acrylic cement. In this context the improvement of the osseointegration and the prevention of infections is a challenge to face in cementless implants. One promising technique is Electrophoretic deposition (EPD)[2] .The aim of this work is to develop a multifunctional and dual surface coating system for permanent titanium orthopedic implants by applying two different cost-effective, scalable and non-complex coating technologies. The first deposit is a sprayed hybrid sol-gel layer with bioactive particles (45S5 Bioglass) and the outer coating consists in a biopolymer/silica- antibiotic composite layer applied by electrophoretic deposition (EPD).The first layer was applied by spray technique at room temperature on Ti grade 2 polished substrates. The sol was made by sol-gel synthesis of Tetraethoxysilane and Methyl triethoxysilane in acidic catalysis. Bioglass particles of 4 microns diameter were suspended in the sol in 10%w/w. The deposition was intended to generate drops of bioactive spots. The upper layer was made by EPD with constant voltage. The solution was a biopolymer mixture of chitosan and gelatin with ethanol as media. Also silica-gentamicin nanoparticles (Si-Ge np) were added to the EPD solution. Coatings were characterized by SEM, XRD,FTIR, contact angle and roughness tests. In vitro tests were carried on to analyze system degradation, antibiotics release and apatite formation. Also cellular and antibacterial tests were held on to determine the cell attachment and bacterial inhibition of the generated composite coatings.EPD coatings were uniform and adapted to the sprayed substrate. After 7 days of immersion almost 80% of gentamicin was release but the bioglass components were being released slower. After 14 days of immersion there were clear hydroxyapatite deposits present. This was confirmed by the cell attachment and proliferation after 7 days. The antibacterial effect was evidenced at 24hs with a big inhibition halo circle around composite coated samples compare with bare ones. The proposed composite system has promising advantageous properties to enhance bone formation and avoid bacterial adhesion of permanent titanium implants.