SANS study on self-assembled structures of glucose-responsive phenylboronate ester-containing diblock copolymer

• Phenylboronate ester-containing diblock copolymer formed vesicles in PBS buffer.
• Vesicles responded differently to 1 and 5 mg/ml glucose.
• A shape transition observed in 5 mg/ml glucose solution.
• Vesicles dissociated and expanded in 0.15 M PBS buffer.

Block copolymers containing boronic acid-functionalized segments belong to an interesting class of materials that can be potentially used in developing self-regulated insulin delivery systems. Determination of the solution structure of these block copolymers is crucial to understanding their performance. Self-assembled structures of glucose-responsive diblock copolymer, poly(ethyleneglycol)-block-poly[(2-phenylboronate esters-1,3-dioxane-5-ethyl)methylacrylate] (PEG-b-PPBDEMA), in aqueous solution were studied using small-angle neutron scattering (SANS). SANS data suggested that PEG-b-PPBDEMA diblock copolymer with a PEG content of 24 wt.% formed vesicles that responded differently to 0.1% and 0.5 wt.% glucose under physiological conditions. Upon elevation of pH, a shape transition to cylinders was observed. The effect of molarity of the buffer on the stability of the vesicles and micelles was also studied.

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