Core-Shell Nanoparticles Fabricated by Tri-capillary Coaxial Electrospray and Template Removal Method for Protein Delivery

A coaxial tri-capillary electrospray and template removal method was proposed to produce nanosized core-shell particles for encapsulating of proteins. Polyethylene glycol (PEG) and poly (D, L-lactide-co-glycolide) (PLGA) were used as corona and shell materials, while Bovine serum albumin (BSA), as a model protein,was entrapped in the core. Microparticles with smooth surfaces and distinct core-shell-corona structures were obtained by coaxial tri-capillary electrospray and nanoparticles with diameter about 100 nm were achieved by removing the corona PEG template from core-shell-corona microparticles. Moreover, the nanoparticle size could be modulated by adjusting the feed rate of shell fluid, and the diameter of nanoparticles could be reduced to (68 +/- 8) nm when the shell fluid feed rate was decreased to 0.5 mL/h. The drug loading content and entrapment efficiency of BSA were 3. 7% and 78. 3%, respectively. It was also found that BSA released from nanoparticles in a typical bi-phased release profile and the process may last for 60 h. The second order structure of BSA released from particles was monitored with circular dichroism spectrum. The results showed that the electrospray process didn ' t affect the second order structure of proteins, implying that the denaturation of the protein didn ' t occur during the process of electrospraying encapsulation.