Preparation and Characterization of pH Responsive Complex Micelles with Dynamic Boronate Cross-Linking

Abstract:

Two kinds of diblock copolymers containing glucose and phenylboronic acid moieties, respectively, poly (ethylene glycol)-b-poly (gluconamidoethyl methacrylate) (PEG-b-PGAMA) and poly (ethylene glycol)-b-poly (2-aminoethyl methacrylate-co-3-nitrophenyboronic acid methacrylate) (PEG-b-P(AMA-co-NPBMA)) were synthesized via atom transfer radical polymerization (ATRP) and post polymerization modification (PPM). Well-defined structure and narrow molecular weight distribution of the polymers were confirmed by proton Nuclear Magnetic Resonance (¹H NMR) and Gel Permeation Chromatography (GPC). Based on the cross-linking between the diol groups of the glycopolymer and phenylboronic acid under physiological pH (7.4), complex micelles composed of PEG outer shell and boronate ester cross-linking core with a hydrodynamic diameter around 20nm were formed. Morphology, size and assembly behavior of the complex micelles were investigated by ¹H NMR, transmission electron microscopy (TEM) and dynamic light scattering (DLS). The results showed the formation/cleavage of boronate ester linkage is reversible upon the variation of solution pH, the complex micelles displayed pH sentiveties of assembling/disassembling behavior. Above pH 7.4, stable spherical micelles can be formed, whereas pH less than 5.5, the micelles dissociated into unimers. Therefore, such pH-responsive micelles based on dynamic complexation of phenyl boronate bonds are expected to be applied to pH-responsive nanodrug carriers

• Periodical: Materials Science Forum (Volume 944)
• Pages: 557-564
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.944.557
• Online since: January 2019
• Authors: Jia Ming Xu, Dan Yue Wang, Han Tong, Xiao Ze Jiang*, Mei Fang Zhu
• Keywords: Boronate, Complex Micelles, Dynamic Covalent Cross-Linking, pH Responsive

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