Preparation and characterization of chitosan nanoparticles containing lysozyme

Abstract Chitosan nanoparticles loaded with lysozyme were prepared by means of an ionic gelation process of chitosan (CS) and tripolyphosphate (TPP) on mild condition. Observations by TEM showed that the spherical chitosan nanoparticles were 50-280 nm in diameter. This work focuses on the effects of molecular weight (Mv) of CS, content of CS, TPP, and initial lysozyme on encapsulation efficiency (EE), loading capacity (LC), release rate and activity of lysozyme in chitosan nanoparticles. Increasing Mv of chitosan, TPP content, or decreasing initial lysozyme content, EE was enhanced whereas when increasing chitosan content, EE first increased then decreased. LC increased as Mv of chitosan, content of TPP, or initial lysozyme increased or chitosan content decreased. The EE could be up to 47.3% and the LC could be 11.4%. The lysozyme release rate increased with decreasing the initial amount of lysozyme, Mv, or content of chitosan and increasing the amount of TPP. The relative activity of lysozyme in all the samples was maintained above 85%.