Size Exclusion Chromatography Coupled with Multi-Angle Light Scattering Analysis of Physicochemical Properties of Block Copolymer Micelles

Abstract

In this study, we report the physicochemical properties of three types of block copolymer micelles as measured by means of size exclusion chromatography coupled with multi-angle light scattering (SEC–MALS). Micelles were prepared from doxorubicin (Dox)-, Nile Red-, and 4-(N,N-dimethylsulfamoyl)-2,1,3-benzoxadiazole (DBD)-conjugated block copolymers. The molar mass and radius of gyration of the block copolymer micelles were measured, and the association number of the polymers was calculated from the measured molar mass. When the chemical structure of the block copolymers was varied (i.e., by varying the poly(ethylene glycol) chain length or by varying the polymerization degree of poly(aspartic acid)), the physicochemical properties of the resultant micelles differed markedly. The association number of the Dox-conjugated polymeric micelles was about 2.3 and 2.7 times as high as those of DBD- and Nile Red-conjugated polymeric micelles, respectively. The radius calculated from SEC–MALS was compared with that calculated from dynamic light scattering, and the ratio of the two radii provided information about the conformation of the resultant micelles.