Abstract：
Chirality is ubiquitous in nature, and closely related to biological phenomena. Nature-originated nanomaterials such as cellulose nanocrystals (CNCs) are able to self-assemble into hierarchical chiral nematic CNC films and impart handedness to nano and micro scale. However, the effects of the chiral nematic surfaces on cell adhesion are still unknown. Herein, this work presents evidence that the left-handed self-assembled chiral nematic CNC films (L-CNC) significantly improve the adhesion of L929 fibroblasts compared to randomly arranged isotropic CNC films (I-CNC). The fluidic force microscopy-based single-cell force spectroscopy is introduced to assess the cell adhesion forces on the substrates of L-CNC and I-CNC, respectively. With this method, a maximum adhesion force of 133.2 nN is quantified for mature L929 fibroblasts after culturing for 24 h on L-CNC, whereas the L929 fibroblasts exert a maximum adhesion force of 78.4 nN on I-CNC under the same condition. Moreover, the instant SCFS reveals that the integrin pathways are involved in sensing the chirality of substrate surfaces. Overall, this work offers a starting point for the regulation of cell adhesion via the self-assembled nano and micro architecture of chiral nematic CNC films, with potential practical applications in tissue engineering and regenerative medicine.
摘要：
手性在自然界中无处不在，与生物现象密切相关。源自自然的纳米材料，例如纤维素纳米晶体（CNCs）能够自组装成分层的手性向列型CNC膜，并赋予纳米和微米级的手性。然而,手性向列表面对细胞粘附的影响尚不清楚。在这里，我们提供的证据表明，与随机排列的各向同性CNC膜（I-CNC）相比，左手自组装的手性向列型CNC膜（L-CNC）显着改善了L929成纤维细胞的粘附。引入基于流体力显微镜（FluidFM）的单细胞力谱（SCFS）来评估L-CNC和I-CNC基底上的细胞粘附力，分别。使用这种方法，在L-CNC上培养24小时后，成熟L929成纤维细胞的最大粘附力为133.2nN，而L929成纤维细胞在相同条件下对I-CNC施加的最大粘附力为78.4nN。此外，瞬时单细胞力谱表明，细胞粘附力的这种差异在细胞粘附的早期阶段上升，L929成纤维细胞与L-CNC或I-CNC基底接触5s内。有趣的是，用RGD肽阻断跨膜整合素后，细胞粘附力的差异消失，表明整合素途径参与感测基底表面的手性。此外,免疫荧光染色和粘着斑蛋白的Westernblot分析表明，L-CNC底物上的talin表达和F-actin组装上调，而Y397-磷酸化粘着斑激酶（FAKY397）的表达无统计学差异，维古林,和α-肌动蛋白。我们的发现表明，talin的上调是促进细胞在L-CNC膜上粘附的关键因素。总的来说,这项工作提供了一个起点，通过自组装的纳米和微结构的手性向列型数控膜细胞粘附的调控，在组织工程和再生医学中具有潜在的实际应用。本文受版权保护。保留所有权利。
