Separation of monodisperse alginate nanoparticles and effect of particle size on transport of vitamin E

Four batches of oleoyl alginate ester (OAE) nanoparticles with narrow size distribution were rapidly separated from the initial batch of nanoparticles by means of centrifugation at the relative centrifugal force (RCF) between 270 × g and 6750 × g after adjusting the zeta potential. The size of nanoparticles decreased with increasing speed of centrifugation, and the polydispersity of nanoparticles significantly decreased. As particle size increased the loading capacity also increased, while transport across Caco-2 cells and the cellular uptake of nanoparticles in jejunum decreased. Endocytosis of nanoparticles around 50 nm/120 nm, 420 nm and 730 nm occur mainly via clathrin-mediated endocytosis, caveolae-mediated endocytosis and macropinocytosis respectively. These results show that centrifugation could separate nanoparticles with appropriate zeta potential into different sizes and the transport and cellular uptake of OAE polysaccharide nanoparticles were size dependent.