Novel protein-loaded chondroitin sulfate–chitosan nanoparticles: Preparation and characterization

In this study, the potential of chondroitin sulfate (ChS)–chitosan (CS) nanoparticles (NPs) for the delivery of proteins was investigated. ChS–CS NPs were prepared by ionic cross-linking of CS solution with ChS. The aggregation line, particle size and zeta potential were investigated as a function of the pH, weight ratio and concentration. The water content and formation yield of the NPs were measured by gravimetry. Results indicated that ChS–CS NPs showed a higher degree of ionic cross-linking and formation yield than sodium tripolyphosphate–CS NPs. Fluorescein isothiocyanate conjugate bovine serum albumin (FITC–BSA), a model protein drug, was incorporated into the ChS–CS NPs. The encapsulation efficiency was obviously increased with the increase in initial FITC–BSA concentration and was as high as 90%. In vitro release studies of ChS–CS NPs showed a small burst effect following a continued and controlled release. Cytotoxicity tests with Caco-2 cells showed no toxic effects of ChS–CS NPs. The ex vivo cellular uptake studies using Caco-2 and HEK-293 cells indicated that NPs were found to be endocytosed into the cells. In conclusion, ChS–CS NPs are a potential new delivery system for the transport of hydrophilic compounds such as proteins.