Synthesis and\nCharacterization of Polyion Complex\nMicelles with Glycopolymer Shells for Drug Delivery Carriers

Double hydrophilic diblock copolymers (G<sub>20</sub>A<sub>100</sub> and G<sub>100</sub>A<sub>98</sub>), composed of non-charged\npoly(glycosyloxyethyl\nmethacrylate) (PGEMA, G) and cationic poly((3-acrylamidopropyl)trimethylammonium\nchloride), were synthesized via reversible addition–fragementation\nchain transfer (RAFT) radical polymerization. Likewise, diblock copolymers\n(G<sub>20</sub>S<sub>80</sub> and G<sub>100</sub>S<sub>78</sub>),\ncomposed of PGEMA and anionic poly(2-acrylamido-2-methylpropanesulfonate)\nwere synthesized via RAFT. The subscripts in these abbreviations indicate\nthe degree of polymerization (DP) of each block. Polyion complex (PIC)\naggregates (G<sub>20</sub>A<sub>100</sub>/G<sub>20</sub>S<sub>80</sub> and G<sub>100</sub>A<sub>98</sub>/G<sub>100</sub>S<sub>78</sub>)\nwere formed through electrostatic interactions by combining oppositely\ncharged diblock copolymers with matched DPs for charge neutralization.\nThe hydrodynamic radii of the G<sub>20</sub>A<sub>100</sub>/G<sub>20</sub>S<sub>80</sub> and G<sub>100</sub>A<sub>98</sub>/G<sub>100</sub>S<sub>78</sub> PIC aggregates were 77.4 and 26.2 nm, respectively,\nwith zeta potentials close to 0 mV. The G<sub>20</sub>A<sub>100</sub>/G<sub>20</sub>S<sub>80</sub> PIC micelles tend to form intermicellar\naggregates, resulting in an increase in the particle size over time.\nIn contrast, G<sub>100</sub>A<sub>98</sub>/G<sub>100</sub>S<sub>78</sub> PIC micelles exhibited colloidal stability with a constant spherical\ncore–shell shape, which was unaffected by time. The morphology\nand stability of the PIC aggregates depend upon the DP ratio of PGEMA\nand oppositely charged polyelectrolyte blocks. Both G<sub>20</sub>A<sub>100</sub>/G<sub>20</sub>S<sub>80</sub> and G<sub>100</sub>A<sub>98</sub>/G<sub>100</sub>S<sub>78</sub> PIC aggregates dissociated\nabove 0.8 M NaCl due to the screening effect of NaCl.