Calcium alginate fibres with an average diameter of 5 μm were prepared by extruding an aqueous sodium alginate solution through nozzles with holes of 0.1 mm diameter into an aqueous calcium chloride solution, and then through a calcium chloride methanol solution. The ratio of D-mannuronate (M) to L-gluronate (G) subunits in the calcium alginate ranged from 0.7 to 2.0. The fibres were soaked in an aqueous saturated calcium hydroxide solution for 5 d, and then soaked in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma. Fibres with an M/G ratio of 2.0 had apatite deposited on their surfaces within 7 d in SBF, but fibres with M/G ratios of 0.7 and 1.5 did not. The higher apatite-forming ability of the former fibres was attributed to their release of more calcium ions from the fibres, that is, the formation of a larger number of free carboxyl groups, effective for apatite nucleation and more efficient acceleration of the apatite nucleation by increasing the ionic activity product of the apatite in SBF.
ASJC Scopus subject areas
- 化学 (全般)