Microalgae is a promising candidate for reducing greenhouse gas and producing renewable biofuels. For microalgae biofilm cultivation, a strong adhesion ability of microalgae cells onto the surface is a prerequisite to resist the fluid shear stress, while strong adhesion is not of benefit to the biofilm harvesting process. To solve this dilemma, a thermoresponsive surface (TMRS) with lower critical solution temperature of 33 °C was made by grafting N-isopropylacrylamide onto a silicate glass slide. The wettability of the TMRS changed from hydrophilic (contact angle of 59.4°) to hydrophobic (contact angle of 91.6°) when the temperature rose from 15 to 35 °C, resulting in the increase of adhesion energy of the TMRS to Chlorella vulgaris cells by 135.6%. The experiments showed that the cells were more likely to attach onto the TMRS at the higher temperature of 35 °C owing to the surface microstructures generated by the hydrogel layer shrinkage, which is similar in size to the microalgae cells. And the cell coverage rate on TMRS increased by 32% compared to the original glass surface. Conversely, the cells separate easily from the TMRS at a lower temperature of 15 °C, and the cell adhesion density was reduced by 19% due to hydrogel layer swelling to a relatively flat surface.

中文翻译：

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可收缩水凝胶聚（N-异丙基丙烯酰胺）接枝的热敏表面，用于控制生物膜培养过程中微藻细胞的粘附。

微藻是减少温室气体和生产可再生生物燃料的有希望的候选人。对于微藻生物膜培养，微藻细胞对表面的强粘附能力是抵抗流体剪切应力的先决条件，而强粘附对生物膜收获过程没有好处。为了解决这个难题，通过将N-异丙基丙烯酰胺接枝到硅酸盐玻璃载玻片上，制得了具有较低临界溶液温度33°C的热响应表面（TMRS）。当温度从15升至35°C时，TMRS的润湿性从亲水性（接触角为59.4°）变为疏水性（接触角为91.6°），导致TMRS对寻常小球藻的粘附能增加。单元数增加了135.6％实验表明，由于水凝胶层收缩产生的表面微观结构（与微藻细胞大小相似），在35°C的较高温度下，细胞更有可能附着在TMRS上。与原始玻璃表面相比，TMRS上的细胞覆盖率提高了32％。相反，在15°C的较低温度下，细胞容易与TMRS分离，并且由于水凝胶层溶胀到相对平坦的表面，细胞粘附密度降低了19％。