Preparation and Characterization of Chitosan-Based Nanoparticles as Protein Delivery System

In this study, methoxy poly(ethylene glycol)-chitosan-poly (l-lysine) (mPEG-CS-PLL) was synthesized and characterized by 1H NMR, X-ray diffraction spectrometry (XRD), and differential scanning calorimeter (DSC). mPEG-CS-PLL nanoparticles were prepared by ionic cross-linking with tripolyphosphate (TPP) under mild conditions and used as a carrier for protein. To demonstrate the feasibility of mPEG-CS-PLL as a protein carrier, bovine serum albumin (BSA) was used as a model protein and encapsulated in the mPEG-CS-PLL nanoparticles by electrostatic binding. The system showed very high encapsulation efficiency and loading capacity for BSA which was up to 78% and 42%, respectively. Dynamic light scattering (DLS), transmission electron microscopy (TEM), and zeta potential study were further used to measure the size, morphology, and Zeta potential of the nanoparticles. The results indicated that the nanoparticles were spherical with a homogeneous size below 300 nm, and the system was positively charged about +21.78 mV. Moreover, the protein cumulative release from the protein delivery system could reach to 82.5% after 54-h incubation in PBS (pH 7.2) at 37°C. Cell viability tests against L929 cells showed that the cytotoxicity of mPEG-CS-PLL polymers was very low, which was favorable to practical applications. It can be suggested from the above results that the mPEG-CS-PLL can be used as a safe and effective carrier for protein delivery.