关键词: 葡萄糖响应, 生物基胶囊, 层层自组装, 壳寡糖, 聚谷氨酸

Phenylboronic acid and derivatives that conjugate with diol units to form a reversible ester bond could be used for preparation glucose responsive materials. Glucose responsive materials, such as films, hydrogels, and nanoparticles based on phenylboronic acid have been reported to have well glucose-regulated release insulin. However, in these examples, employed polymers were not full degradability or low biocompatibility. Therefore, this study aims to prepare the bio-based capsules with multi-layers structure to response glucose through the layer-by-layer self-assembly of two natural polymers. Poly(γ-glutamic acid-g-3-aminophenylboronic acid) (γ-PGA-g-APBA) and galactosed chitosan oligosaccharide (GC) were synthesized by grafting 3-aminophenylboronic acid (APBA) and lactobionic acid (LA) to poly-γ-glutamic acid (γ-PGA) and chitosan oligosaccharide (CS), respectively, in the presence of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) as catalysts. Chemical structures of γ-PGA-g-APBA and GC were determined by proton nuclear magnetic resonance (¹H NMR) and Fourier transform infrared (FT-IR) spectra. Then, polyelectrolyte microspheres (γ-PGA-g-APBA/GC)₅@SiO₂ were prepared with particle sizes of 240±10 nm, using functionalized silica microspheres as templates by layer-by-layer processes of γ-PGA-g-APBA and GC. Capsules ((γ-PGA-g-APBA/GC)₅) with multi-layer structures were obtained by removing SiO₂ templates in NH₄F/HF (8 mol/L)/(2 mol/L) buffer solution. Sizes and morphologies of polyelectrolyte capsules were characterized by zeta potential, scanning electron micrographs (SEM), transmission electron microscope (TEM) and dynamic light scattering (DLS). The results showed that ((γ-PGA-g-APBA/GC)₅) capsules presented unique hollow structures and had a good stability when capsules were incubated at different temperatures, salt concentrations and pH values. Moreover, ((γ-PGA-g-APBA/GC)₅) capsules showed a good glucose-responsive property. The capsules were swollen and intact at low glucose concentration, while were destroyed at high glucose concentration. These ((γ-PGA-g-APBA/GC)₅) capsules with good stability and glucose-response are expected to be used to the fields of the diagnosis and treatment of diabetes.

Key words: glucose-response, bio-based capsules, layer-by-layer self-assembly, chitosan oligosaccharide, poly(γ-glutamic acid)