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

Abstract

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[(2phenylboronate 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 24wt.% 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.

Effect of Temperature and Hydrophilic Ratio on the Structure of Poly(N-vinylcaprolactam)-block-poly(dimethylsiloxane)-block-poly(N-vinylcaprolactam) Polymersomes

“…43 Recently, in situ SANS elucidated the temperature-responsive behavior of poly(ethyl glycol)-co-polystyrene polymersomes in which particles formed due to aggregation at 55 °C44 and changes in morphology of poly(ethylene glycol)-block-poly[(2-phenylboronate esters-1,3-dioxane5-ethyl)methyl acrylate] and poly-(dimethylsiloxane)-g-poly(ethylene oxide) polymersomes in response to glucose and hypertonic shock, respectively. 45,46 Thus, despite an increasing interest in temperatureresponsive self-assembled statures, including our recent study on synthesis and drug delivery potential of PVCL n −PDMS m − PVCL n polymersomes, 31 there is lack of understanding of their assembly mechanism. The molecular-level picture of their temperature-induced structural changes has been also overlooked, which significantly limits their applications for controlled delivery.…”

“…To characterize self-assembled systems, dynamic/static light scattering can be used to evaluate vesicle size distribution, critical aggregation concentration, and the associated response to temperature or pH change, − while optical microscopy may only resolve giant vesicles with a diameter larger than 1 μm. − In situ small-angle neutron scattering (SANS) is the most relevant technique for characterizing micron and nanometer scale polymersomes as it allows for studying polymersomes in solutions at a wide range of temperatures with angstrom resolution. , The neutron beam is nondestructive and reveals contrast between isotopes of hydrogen, allowing structural characterization of the hydrogen-rich polymersome membrane if assembled in D 2 O . Recently, in situ SANS elucidated the temperature-responsive behavior of poly­(ethyl glycol)- co -polystyrene polymersomes in which particles formed due to aggregation at 55 °C and changes in morphology of poly­(ethylene glycol)- block -poly­[(2-phenylboronate esters-1,3-dioxane5-ethyl)­methyl acrylate] and poly­(dimethylsiloxane)- g -poly­(ethylene oxide) polymersomes in response to glucose and hypertonic shock, respectively. , …”

Model-dependent Small-angle Scattering for the Study of Complex Organic Materials

“…The development of polymeric materials for drug delivery has been investigated heavily in recent years, particularly with SAS. Zhang and co-workers [36] used SANS to study the aqueous structure of the boronic acid-functionalised block co-polymer, PEG-b-PPBDEMA, where the PEG content was 24 wt%. Form factor based analysis was capable of showing an interesting morphological response to the addition of glucose solution.…”

Phenylboronic acid-functionalized polymer nanocarriers for glucose-triggered drug release

“…Yang课题组 [36] 采用ATRP聚合方法得到嵌段共聚 物mPEG5000-b-PPBDEMA, 该共聚物在水溶液中自组 装成的纳米胶束具有良好的葡萄糖敏感性能. 除此之 外, 该两亲性嵌段共聚物还能够组装成纳米囊泡 [59] . 通 Zha课题组 [72] 以SiO2为模板, 采用模板法制备了含 有PNIPAM和聚(N-苯硼酸基丙烯酰胺)的具有温度和 葡萄糖双重敏感性能的空心纳米凝胶.…”