A New Gallium Crosslinked Alginate/Nanobioactive Glass Composite For Bone Tissue Engineering

MOURINO V.; NEWBY P.; CATTALINI JUAN; LUCANGIOLI SILVIA,; BOCCACCINI A.

Jena

Congreso; European Symposium on Biomaterials and Related Areas. Euro BioMat; 2011

Eurobiomat

Recent studies have found that gallium ion (Ga3+), a drug approved for clinical used, inhibits S. aureus. Alginates (ALG) are able to form gels with multivalent metal ions, such as Ga3+, which induce cross-linking of their guluronic residues. In addition, nanoparticulate bioactive glasses (BG) could be also combined with biodegradable polymers to improve the mechanical and physical properties of the matrix increasing its versatility; in particular if an application in BTE is envisaged. The above considerations prompted us to develop a novel nano-bioactive glass containing ALG cross-linked with Ga3+ films. This investigation is a preliminary step for assessing the viability of using these composites in the elaboration of multifunctional 3D scaffolds for BTE with the added value of incorporating a drug delivery system to prevent possible bacterial colonisation of the biomaterial following implant surgery. Films were fabricated using a solvent casting technique following by the immersion into a solution of gallium nitrate for crosslinking. SEM observations showed films with uniform surface morphology in all cases. EDX analysis revealed that Ga3+ ions were successfully incorporated in the films. The tensile strengths at break of the films with BG were significantly higher than the films without BG.  The scaffolds were incubated in simulated body fluid (SBF) at 37°C for different times to evaluate bioactivity. Biomineralization studies showed the deposition of hydroxyapatite on the surface of the films suggesting their bioactive nature. The release of Ga3+, quantified by atomic absorption, was controlled by crosslinking the ion with alginate and the antibacteriostatic properties of the films were confirmed through the antimicrobial disk susceptibility test using S. aureus. Cell proliferation was confirmed in vitro by cell culture studies using osteoblast like human osteosarcoma cells line (MG-63). It was shown that Ga-crosslinked composites films possessed excellent physicochemical, biological and drug-release properties. These preliminary studies suggest that these composite films are thus promising candidates for bone tissue engineering applications and they could be applied to design 3D scaffolds with enhanced bioactivity.