Preparation and characterization of unsaturated poly(3-hydroxyalkanoate) nanoparticles

Nanoparticles with unsaturated poly(hydroxyalkanoate)s (UPHAs) biosynthesized with Pseudomonas oleovorans were prepared by spontaneous emulsification solvent diffusion method. The influence of nanoparticle formation was investigated with various experimental parameters such as sonication conditions, solvent, surfactant and polymer contents, etc. The physical and chemical properties of UPHAs and its nanoparticles were characterized using H-1- and C-13-nuclear magnetic resonance spectroscopies, attenuated total reflection infrared spectroscopy, differential scanning calorimetry and gel permeation chromatography The morphology of particles was observed using scanning electron microscope and the size and distribution of nanoparticles were measured with electrophoretic light scattering spectrophotometer. The mean diameter of particles decreased with increasing sonication amplitude and time. The addition of ethanol into UPHAs chloroform solution decreased the particle size presumably due to increased solvent diffusion into water phase. The particle size increased with increased the concentration of UPHAs solution. Under the 2-4% poly(vinyl alcohol) (PVA) aqueous solution the minimum mean diameter of particles was shown. The higher degree of hydrolysis and degree of polymerization of PVA increased the mean diameter of particles.