Preparation of anionic poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) copolymeric nanoparticles as basic protein antigen carrier

It is an useful method for polymeric nanoparticles to load protein by electrostatic method to improve the immunogenicity of protein antigen. In this article, anionic poly(e-caprolactone)-poly(ethylene glycol)-poly(e-caprolactone) (PCEC) nanoparticles were prepared by modified emulsion solvent evaporation method, and human basic fibroblast growth factor (bFGF), as a model protein, was absorbed onto its surface due to electrostatic interaction. The prepared anionic PCEC nanoparticles, with mean diameter of 136.9 nm, had zeta potential of − 33.14 mV. The surface charge and particle size of bFGF/nanoparticles complex increased with increase of bFGF/nanoparticles mass ratio. The encapsulated bFGF could be released slowly from bFGF/nanoparticle complexes. The animal experiment indicated that the humoral immunity induced by bFGF/PCEC complex was improved greatly than that created by naked bFGF. Otherwise, the cytotoxicity of anionic PCEC nanoparticles was also evaluated by 293 cell viability. The prepared anioni...