Department of Mechanical Engineering, Catholic University of America, Washington, District of Columbia 20064, USA.
Department of Biomedical Engineering, Catholic University of America, Washington, District of Columbia 20064, USA.
Lab Chip. 2022 Aug 23;22(17):3203-3216. doi: 10.1039/d2lc00481j.
Chemotaxis is a fundamental bacterial response mechanism to changes in chemical gradients of specific molecules known as chemoattractant or chemorepellent. The advancement of biological platforms for bacterial chemotaxis research is of significant interest for a wide range of biological and environmental studies. Many microfluidic devices have been developed for its study, but challenges still remain that can obscure analysis. For example, cell migration can be compromised by flow-induced shear stress, and bacterial motility can be impaired by nonspecific cell adhesion to microchannels. Also, devices can be complicated, expensive, and hard to assemble. We address these issues with a three-channel microfluidic platform integrated with natural biopolymer membranes that are assembled . This provides several unique attributes. First, a static, steady and robust chemoattractant gradient was generated and maintained. Second, because the assembly incorporates assembly pillars, the assembled membrane arrays connecting nearby pillars can be created longer than the viewing window, enabling a wide 2D area for study. Third, the assembled biopolymer membranes minimize pressure and/or chemiosmotic gradients that could induce flow and obscure chemotaxis study. Finally, nonspecific cell adhesion is avoided by priming the polydimethylsiloxane (PDMS) microchannel surfaces with Pluronic F-127. We demonstrated chemotactic migration of as well as under well-controlled easy-to-assemble glucose gradients. We characterized motility using the chemotaxis partition coefficient (CPC) and chemotaxis migration coefficient (CMC) and found our results consistent with other reports. Further, random walk trajectories of individual cells in simple bright field images were conveniently tracked and presented in rose plots. Velocities were calculated, again in agreement with previous literature. We believe the biopolymer membrane-integrated platform represents a facile and convenient system for robust quantitative assessment of cellular motility in response to various chemical cues.
趋化性是细菌对特定分子化学梯度变化的基本反应机制，这些特定分子被称为趋化剂或化学排斥剂。开发用于细菌趋化性研究的生物平台对于广泛的生物学和环境研究具有重要意义。已经开发了许多微流控设备来研究它，但仍然存在一些挑战，这些挑战可能会使分析变得模糊。例如，流动引起的剪切应力会损害细胞迁移，非特异性细胞黏附到微通道会损害细菌的运动能力。此外，设备可能复杂、昂贵且难以组装。我们使用集成有天然生物聚合物膜的三通道微流控平台来解决这些问题，这些膜是通过 组装的。这提供了几个独特的属性。首先，生成并维持了静态、稳定和稳健的趋化剂梯度。其次，由于组装采用了组装支柱，因此可以创建比观察窗口更长的连接附近支柱的组装膜阵列，从而可以研究更宽的 2D 区域。第三，组装的生物聚合物膜最大限度地减少了可能诱导流动并掩盖趋化性研究的压力和/或化学渗透梯度。最后，通过用 Pluronic F-127 对聚二甲基硅氧烷 (PDMS) 微通道表面进行预处理，可以避免非特异性细胞黏附。我们展示了 在受控且易于组装的葡萄糖梯度下的趋化性迁移，以及 的趋化性迁移。我们使用趋化性分配系数 (CPC) 和趋化性迁移系数 (CMC) 来表征运动能力，发现我们的结果与其他报告一致。此外，在简单的明场图像中，方便地跟踪和呈现了单个细胞的随机游走轨迹，并以玫瑰图形式表示。再次计算了速度，与之前的文献一致。我们相信，生物聚合物膜集成平台代表了一种简便易用的系统，可用于对各种化学刺激下细胞运动能力进行稳健的定量评估。
