Hydroxyapatite Nanoparticles as Particulate Emulsifier: Fabrication of Hydroxyapatite-Coated Biodegradable Microspheres

摘要

Hydroxyapatite (HAp) nanoparticle-coated micrometer-sized poly(L-lactic acid) (PLLA) microspheres were fabricated via a "Pickering-type" emulsion route in the absence of Lilly molecular surfactants. Stable oil-in-water emulsions were prepared using 40 nm HAp nanoparticles as a particulate emulsifier and a dichloromethane (CH2Cl2) Solution of PLLA as an oil phase. It wits clarified that the interaction between carbonyl/carboxylic acid groups of PLLA and the HAp nanoparticles tat the CH2Cl2-water interface played a crucial role to prepare the stable Pickering-type emulsion. The HAp nanoparticle-coated PI L,A microspheres were fabricated by the evaporation of CH2Cl2 from the emulsion and characterized in terms of size, particle size distribution. and morphology using scanning/transmission electron microscopes. Scanning electron microscopy study and ultrathin cross section observation using transmission electron microscopy confirmed adsorption of the HAp nanoparticles only at the surface of the PLLA microspheres. Cell-adhesion experiments suggested the HAp nanoparticles on the surface of the PLLA microspheres promoted the cell adhesion and spreading.