Nanoparticulation of bovine serum albumin and poly-d-lysine through complex coacervation and encapsulation of curcumin.

Soluble coacervate nanoparticles were fabricated by mixing bovine serum albumin (BSA) and poly-d-lysine with low (LMW-PDL) and high molecular weights (HMW-PDL). The particle size was influenced by molecular weight, mass ratio of polyelectrolytes (PEs), and salt concentration. The smallest nanoparticles had a diameter of 212±11nm which was achieved with LMW-PDL dissolved with 0.1M NaCl at pH 7 and a mass ratio of 2.0 (BSA: PDL). SEM images showed that coacervate nanoparticles of LMW-PDL are relatively spherical in shape, while nanoparticles of HMW-PDL were irregular. Crosslinking of the protein/polypeptide with glutaraldehyde had variable impact on the stability and particle size over 21days at 4 and 25°C. The encapsulation efficiency (EE) for curcumin to BSA molar ratio of 0.5 was 47%. The EE increased to 60% when the curcumin to BSA molar ratio was 10 with a loading capacity of 22μg of curcumin per mg of coacervate nanoparticles. The average particle size of the loaded colloidal dispersions increased as the curcumin concentration was increased. For the colloidal dispersions with 0.5 molar ratio of curcumin to BSA, the particle size was around 204±14nm at day 1, while the nanoparticles with molar ratio of 10 showed a particle size around 316±43nm. The curcumin loaded BSA:LMW-PDL nanoparticles were pretty stable over a period of 21days.