In Situ Growth Kinetics of Hydroxyapatite on Electrospun Poly(DL-lactide) Fibers with Gelatin Grafted

Development of fibrous nanocomposites of hydroxyapatite (HA) and poly(DL-lactide) (PDLLA) offers great potential as tissue engineering scaffolds. Attempts have been made to solve problematic issues of the agglomeration of HA crystallites in fibrous mats to enhance the mechanical property and bioactivity. A novel method was introduced in the present study to use electrospun PDLLA nanofibers with surface modifications as the induction sites for composite fabrication. Free amino groups were created on electrospun fibers through an optimized aminolysis process, and gelatin was further grafted on the aminolyzed fibers through glutaraldehyde coupling. In the aminolysis and gelatin grafting process, the amount of amino groups and gelatin could be modeled with quantitative equations as a function of the aminolysis time. The formation of nonstoichiometric nanostructured HA and good dispersion on electrospun fibers were determined. Gelatin was demonstrated to control the nucleation and growth of crystals on fibrous templates, and kinetic equations of HA growth were drafted as a function of the incubation time for fibrous mats with different gelatin contents. The amount of HA formed on the fibrous composites and the crystal size were regulated through the content of grafted gelatin, which could be further determined by the aminolysis process.