Calcium incorporation into silica/gelatin hybrids for tissue engineering

With an aging population and an increase in the proportions of that population with access to high quality health care the need for a synthetic bone regenerative scaffold continues to increase. Mahony et al. produced an encouraging type II silica-gelatin hybrid with tailorable properties but without calcium content. This work focuses on investigating methods for including calcium into that material. Calcium chloride and various monobasic calcium phosphate compositions were investigated via SBF analysis followed by SEM, EDX, FTIR, XRD and BCA assay analysis. It was found that while an increasing fraction of monobasic calcium phosphate increased the rate of calcium phosphate deposition in SBF trials the synthesis route (especially drying) proves unreliable. Although some suggestion that incorporation of calcium into the silica network occurred was found, no clear evidence thereof could be determined. The use of a synthetic polymer to increase the amount of calcium chelating COOH groups in the material was investigated via addition polymerisation of methacrylic acid. Monoliths were produced and they were found to significantly increase the rate of calcium phosphate deposition onto the material surface. The possibility of crosslinking pMAA using GPTMS via the same route as used for gelatin was explored but found not to lead to crosslinking at COOH sites on the polymer. The work done suggests that a number of routes exist for improving the bioactivity and osteogenic character of type II silica gelatin scaffolds, considerable work remains to fully characterise these approaches.Open Acces