Facile technique for preparing organic-inorganic composite particles: Monodisperse poly(lactide-co-glycolide) (PLGA) particles having silica nanoparticles on the surface

This paper presents a facile technique for preparing organic-inorganic composite particles. The technique involves coating 50-nm silica nanospheres as model composites on the surface of monodisperse PLGA particles. Monodisperse poly(lactide-co-glycolide) (PLGA) particles (size: 2.0 p.m) with molecular weights (Mw) of 5000, 10,000, 15,000, and 20,000 are first prepared using a Shirasu porous glass (SPG) membrane emulsification technique and a solvent evaporation method. Monodisperse PLGA particles (sizes: 0.70, 1.00, 2.00, and 3.00 mu m Mw: 20,000) are also prepared by varying the pore size of the SPG membrane used. The surfaces of the prepared PLGA particles are modified by the adsorption of a polyelectrolyte having counter-ions, which results in the formation of positively charged PLGA particles from the original anionic particles. Silica nanospheres (size: 50 nm) are coated on the surface of the modified PLGA particles via electrostatic interaction in order to prepare the organic-inorganic composite particles. Compared with simple PLGA particles, the prepared composite particles have a unique functionality for biological applications. (C) 2010 Elsevier B.V. All rights reserved.