Controlled assembly of Poly(D,L-lactide-co-glycolide)/hydroxyapatite core-shell nanospheres under ultrasonic irradiation

An ultrasound field was applied to obtain PLGA/HAp biocomposite nanospheres. Formulation of PLGA/HAp, composite revealed significant dependence of the morphology of the obtained composite on synthesis parameters, like the intensity of applied ultrasonic field, polymeric and ceramic parts' wt.% ratio in the composite, temperature of the medium, type of surfactant, and the sequence of steps in the formation of PLGA/HAp. Optimal parameters for the formation of PLGA/HAp included a lower content of the ceramic phase (PLGA/HAp = 90: 10), higher power of ultrasonic field (P = 142.4 W), lower temperature of the medium during ultrasonic treatment (T = 8 degrees C), dilute solution of PVP as surfactant and dispersion of hydroxyapatite in polymer solution in order to achieve required homogeneity before the formulation of the composite. The morphology of PLGA/HAp particles synthesized under these conditions was highly regular: sphere-like, with particles of very small dimensions (150-320 nm), highly uniform particle size distribution and characteristic planar spatial self-organization. These characteristics indicate significant improvements in PLGA/HAp composite resulting from ultrasonic method. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.