Formation of complex nanoparticles (CNPs) from a spherical protein (bovine serum albumin) and a polycation (poly-D-lysine with two molecular weights) using coacervation method

摘要

Complex nanoparticles (CNPs) were formed by mixing BSA and Poly-D-Lysine with low (LMW-PDL) and high molecular weights (HMW-PDL). BSA and both PDL are oppositely charged biopolymers in neutral and alkaline pHs; so they can interact by physically mixing of them. This interaction was established by the zeta potential of BSA and both PDLs before and after mixing. The minimum effective diameter, in the range of 200±1.40nm and 215±1.97nm, was achieved with LMW-PDL dissolved in PBS with 0.1M NaCl at pH 7 and a mass ratio of 2.0 (BSA:PDL). Particle sizes decreased at 101±7.02nm with the addition of 0.25% glutaraldehyde as cross-linking agent. CNPs from HMW-PDL showed diameters around 250±32.8nm and 300±24.4nm; the addition of 0.25% glutaraldehyde decreased particle size to 200±1.75nm and 220±3.05nm. CNPs of LMW-PDL and BSA were more stable during 21 days with the addition of 0.25% glutaraldehyde, while CNPs of HMW-PDL were stable during 21 days with and without the addition of glutaraldehyde, either at room temperature (～25 °C) or refrigeration temperature (4-8 °C).