基于固-气-液界面下细菌纤维素的合成

Bacterial Cellulose Synthesis at Solid-Gas-Liquid Interface

细菌纤维素(bacterial cellulose, BC)是一种由葡糖木醋杆菌在生长运动过程中合成的具有纳米尺寸的纤维素. BC因其良好的生物相容性和机械性能使其在生物医学方面得到广泛研究和应用.针对葡糖木醋杆菌氧气需求较敏感的特点,制造了表面具有不同结构微柱的光刻硅片,并进一步在硅片表面蒸镀一层十七氟癸基三甲氧基硅烷,使硅片具有超疏水特性,通过喷壶将不同液滴大小的菌液喷洒在该硅片上,形成"固-气-液"三相界面,解决有序微模板与细菌培养液之间的氧气需求问题,并根据液滴大小的不同,获得了许多精细的微尺寸纤维结构.进一步地,在纤维网上培养细胞,探索了其在细胞捕获方面的应用.

Bacterial cellulose(BC) is a nano-size cellulose synthesized by Gluconacetobacter xylinus during its growth and movement. Due to its good biocompatibility and good mechanical property, BC has been widely studied and applied in biomedicine and tissue engineering. Gluconacetobacter xylinus is a kind of aerobic bacteria,which preferentially synthesizes a BC film at the gas-liquid interface. Aiming at the sensitive characteristics of oxygen demand of Gluconacetobacter xylinus, we referred the method of "solid-gas-liquid" three-phase interface formed on the interface of superhydrophobic nanomaterials in aqueous solution. Photolithographic silicon substrate with different micropillar structure on the surface were manufactured, and further evaporated a layer of heptadecafluorodecyltrimethoxysilane on the surface of silicon substrate, which made the silicon substrate superhydrophobic. Different sizes of medium with bacterial droplet sprayed on the silicon substrate through a sprinkling can, which made medium droplets were limited contact with the top of micropillar on the photolithographic silicon substrate to form a "solid-gas-liquid" interface, to solve the oxygen demand problem between ordered microstructure template and bacterial culture medium. Therefore, many micro-size fibers obtained due to the different sizes of droplet, including BC nanowire, BC wall, BC ball and BC network. When bacterial medium droplet rolling on pillar-structured photolithographic(~ 5 μL) formed BC nanowire between tips of two micropillar, large droplet(10 – 20 μL) formed BC wall between two micropillars, over 30 μL droplet formed BC network on micropillars. Furthermore, large droplet(10 – 20 μL) formed BC balls instead of BC network on large space(20 μm) vertical pillar-structured photolithographic silicon substrates, micro droplet(~ 1 μL)formed single BC ball on small space(5 μm) vertical pillar-structured photolithographic silicon substrates. In addition, HaCAT cells could culture on the BC network that means BC network synthesize in this way could capture adherent cells. Finally, challenges and opportunities of this BC synthesis method and its BC products toward future applications were discussed.