Synthesis and characterization of fluorescent chitosan–ZnSe/ZnS nanoparticles for potential drug carriers

The objective of the study is to describe a new approach of combining quantum dots into chitosan as an anti-cancer drug carrier. Novel chitosan-ZnSe/ZnS (CS-ZnSe/ZnS) nanoparticles were synthesized by a one-step ionic gelation technique, with ZnSe/ZnS quantum dots (ZnSe/ZnS QDs) as cross-linking agent and for fluorescent labeling. The approach not only avoids the use of emulsifiers and chemical cross-linking agents but also prevents the possibility of damage to drugs. The fluorescent CS-ZnSe/ZnS nanoparticles were about 100-500 nm in size and stable in a physiological environment. Low cytotoxicity was ensured by investigation with mouse lung carcinoma cells. The cell viability remained 99% when the concentration of CS-ZnSe/ZnS nanoparticles increased to 200 mu g mL(-1). In the in vitro drug release experiment, 5-fluorouracil (5-Fu) loaded within CS-ZnSe/ZnS nanoparticles had more preferable sustained-release performance and longer equilibrium time compared with that of the pure 5-Fu. The fluorescent CS-ZnSe/ZnS nanoparticles are expected to be used for biological fluorescent labeling and drug carriers.