GALLIUM RELEASING 3-D BIOACTIVE GLASS SCAFFOLD FOR BONE TISSUE ENGINEERING

V MOURIÑO, P. NEWBY, A. BOCCACCINI

Leipzig

Conferencia; World Conference on Regenerative Medicine 2009; 2009

The Fraunhofer Institute for Cell Therapy and Immunology

Ga3+, a drug already approved for clinical used, was recently fount to inhibit methicilin resistant S. aureus. Ga3+ can disrupt Fe3+-dependent process of many infecting bacteria which can not differentiate between Ga3+ and Fe3+. Combinations of 45S5 Bioglass (VG) scaffolds with biodegradable polymers for bone tissue engineering have not been yet combined with Ga3+ as a prophylaxis against infections following implant surgery. The above considerations prompted us to develop a multifunctional implantable scaffold with drug delivery capabilities for the controlled release of Ga3+ and its properties in terms of antibacterial activity against S. aereus were investigated. VG 3 D scaffolds were fabricated using the foam replica technique followed by sinterisation. Ga3+ solution was added drop wise to the scaffold. Then, an excess of a solution of sodium alginate (ALG) was used to coat the scaffold and cross-linked with Ga3+. Morphology features were observed using SEM and the compositional effect on the structure of the coating was evaluated by FT-IR. The contact angle was determined to confirm hydrophilicity. The scaffolds were incubated in simulated body fluid (SBF) at 37°C for different follow-up times to evaluate bioactivity. In vitro release studies of Ga3+ from ALG coated scaffolds were performed at 37°C in buffer phosphate solution (PBS). Aliquots were collected at predetermined time intervals for 10 days and were used to investigate their ability to inhibit S. aureus. For each time interval, colony forming units were determined. SEM examinations shown that the alginate slurry was attached both onto the outer and inner surface of the scaffold forming a uniform coating. No blockage of porous was observed. FT-IR spectroscopy analysis showed no new chemical bonds between VB and ALG and the crossliking between Ga3+ and ALG was confirmed. The bioactivity of the novel multifunctional scaffolds was confirmed by the formation of apatite layer after 3 days in SBF and contact angle measurements confirmed hydrophilicity. The controlled amount of Ga3+ released from the coated scaffold during the 10 days of study was enough to inhibit the development of S aereus. In the same conditions of study, the uncoated scaffold was not efficient to inhibit the development of S aereus. The resulting Ga+3 loaded VG scaffold coated with ALG was useful in inhibiting the development of the most common causative bacteria of bone infections without decreasing its high bioactivity level.