Preparation of amphiphilic poly(L-lactide)-graft-chondroitin sulfate copolymer self-aggregates and its aggregation behavior

Novel polymeric amphiphilic copolymers were synthesized using chondroitin sulfate (CS) as a hydrophilic segment and poly(L-lactide) (PLLA) as a hydrophobic segment. Micelles of those copolymers were formed in an aqueous phase and were characterized by 1H NMR spectra, fluorescence techniques, dynamic light scattering (DLS), atomic force microscopy (AFM), and confocal microscopy. Their critical aggregation concentrations (CAC) are in the range of 0.0043-0.0091 mg/mL at 25 degrees C. The partition equilibrium constants, Kv, of the pyrene probe in the aqueous solution were from 3.65 x 10(5) to 1.41 x 10(6) at 25 degrees C. The mean diameters of the micelles were below 200 nm, and their sizes were narrowly distributed. The AFM images revealed that the self-aggregates were spherical. Additionally, the CSn-PLLA micelles can efficiently transport within the cells via endocytosis as observed from confocal microscopy.