When screening microbial populations or consortia for interesting cells, their selective retrieval for further study can be of great interest. To this end, traditional fluorescence activated cell sorting (FACS) and optical tweezers (OT) enabled methods have typically been used. However, the former, although allowing cell sorting, fails to track dynamic cell behavior, while the latter has been limited to complex channel-based microfluidic platforms. In this study, digital microfluidics (DMF) was integrated with OT for selective trapping, relocation, and further proliferation of single bacterial cells, while offering continuous imaging of cells to evaluate dynamic cell behavior. To enable this, magnetic beads coated with Salmonella Typhimurium-targeting antibodies were seeded in the microwell array of the DMF platform, and used to capture single cells of a fluorescent S. Typhimurium population. Next, OT were used to select a bead with a bacterium of interest, based on its fluorescent expression, and to relocate this bead to a different microwell on the same or different array. Using an agar patch affixed on top, the relocated bacterium was subsequently allowed to proliferate. Our OT-integrated DMF platform thus successfully enabled selective trapping, retrieval, relocation, and proliferation of bacteria of interest at single-cell level, thereby enabling their downstream analysis.

中文翻译：

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使用微镊子进行单个细菌捕获和选择性提取的数字微流控技术

在筛选微生物种群或菌群中有趣的细胞时，它们的选择性检索以供进一步研究可能会引起极大兴趣。为此，通常使用传统的荧光激活细胞分选（FACS）和光镊（OT）启用的方法。但是，前者虽然允许进行细胞分类，但无法跟踪动态细胞行为，而后者则仅限于基于复杂通道的微流体平台。在这项研究中，数字微流控技术（DMF）与OT集成在一起，用于选择性捕获，迁移和进一步增殖单个细菌细胞，同时提供连续的细胞成像以评估动态细胞行为。为此，用沙门氏菌包被的磁珠鼠伤寒沙门氏菌-靶向抗体的DMF平台的微孔阵列中接种，并用于捕获的荧光的单细胞S.伤寒群。接下来，使用OT根据其荧光表达选择带有目标细菌的微珠，并将该微珠重新定位到相同或不同阵列上的不同微孔中。使用贴在顶部的琼脂贴片，随后使重新定位的细菌增殖。因此，我们的OT集成DMF平台成功地实现了在单细胞水平上选择性诱捕，回收，重定位和扩散感兴趣的细菌，从而实现了其下游分析。