Preparation and Characterization of Quantum Dots-tagged Self-Assembly Nanoparticles

摘要

Various Stearic acid modified Lysine grafted Chitosan (SA-LysCS) with the same degree of substitute (DS) of Stearic acid (4.9%) and different DS of Lysine (2.3%, 4.7%, 9.3%) were synthesized through the 1-ethyl-3-(3-dimethylaminopropyyl)-carbodiimide (EDC) mediated reaction. Structural characteristics of the resultants were investigated by FT-IR and 1H NMR. The critical aggregation concentration (CAC) of the self-aggregated SA-LysCS were determined by measuring the fluorescence intensity of pyrene, which was in the range of 1.1-5.3×10-2 mg/ml and the value increased with the DS of Lysine increasing. The average particle size of the self-aggregates in distilled water was in the range of 132.6-300.2nm, which increased with continuous addition of Lysine as well. These self-assemble nanoparticles were tagged by TOPO-capped green quantum dots (QDs). Transmission electron microscopy (TEM) studies showed that the QDs have been located inside the hydrophobic cores of the polymeric micelles, and the flurescent intensity of green QDs decreased after encapsulation due to the coverage of the micelles. In summary, the nanoparticles prepared in this work are expected to have great potential in bio-detection or biotherapy fields.