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

Abstract In this study, methoxy poly(ethylene glycol)‐chitosan‐poly ( l ‐lysine) ( mPEG ‐ CS ‐ PLL ) was synthesized and characterized by 1 H 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.