Physicochemical characterization of self-assembled poly(€-caprolactone) grafted dextran nanoparticles

Amphiphilic graft copolymer composed of poly(€-caprolactone) and dextran was synthesized by ring opening polymerization of €-caprolactone initiated through the hydroxyl end of dextran in the presence of stannous 2-ethylhexanoate [Sn (oct)₂] as a catalyst. It has been widely characterized by Fourier transform infrared spectroscopy, ¹H NMR, and thermogravimetric analysis. Nanoparticles were prepared in aqueous medium by co-solvent evaporation technique at room temperature (25 °C). Hydrodynamic diameter and particle size were measured by dynamic light scattering spectroscopy and atomic force microscopy, respectively. Core-shell geometry of polymeric nanoparticle was characterized by fluorescence spectrophotometer using pyrene as a probe. Critical micelle concentration of polymer in triple distilled water decreased from 6.9 × 10^-4 to 8.9 × 10^-4 g/l with increasing hydrophobic moiety. Further, the physiological stability of the nanoparticles in phosphate buffer saline of pH 7.4 at 37 °C was evaluated, which showed promising in drug delivery system.