Successful lysis of cells/microorganisms is a key step in the sample preparation in fields like molecular biology, bioengineering, and biomedical engineering. This study therefore aims to investigate the lysis of bacteria on-chip and its dependence on both microfluidic channel structure and flow rate. Effects of temperature on lysis on-chip were also investigated. To perform these investigations, three different microfluidic chips were designed and produced (straight, zigzag and circular configurations), while the length of the channels were kept constant. As an exemplary case, Mycobacterium smegmatis was chosen to represent the acid-fast bacteria. Bacterial suspensions of 1.5 McFarland were injected into the chips at various flow rates (0.6- $8~\mu \text{l}$ /min) either at room temperature or 50° C. In order to understand the on-chip lysis performance fully, off-chip experiments were carried out at durations which are equal to those bacteria spent in the channel from inlet to the outlet at different flow rates. We also performed COMSOL multiphysics program simulations to evaluate further the effect of the applied parameters. As a result, we found that the structure and the flow rate do not affect lysis over all in all investigated channel types, however on-chip experiments at room temperature produced more effective lysis compared to the on-chip and the off-chip samples performed at higher temperatures. Interestingly on-chip experiments at higher tempratures do not result in effective lysis.

中文翻译：

---

通道结构和流速对片上细菌裂解影响的研究

细胞/微生物的成功裂解是分子生物学、生物工程和生物医学工程等领域样品制备的关键步骤。因此，本研究旨在研究芯片上细菌的裂解及其对微流体通道结构和流速的依赖性。还研究了温度对片上裂解的影响。为了进行这些研究，设计和生产了三种不同的微流控芯片（直线、锯齿形和圆形配置），同时通道的长度保持不变。作为典型案例，耻垢分枝杆菌被选为代表抗酸细菌。将 1.5 McFarland 的细菌悬浮液以不同的流速（0.6- $8~\mu \text{l}$ /min) 在室温或 50°C 下。为了充分了解芯片上的裂解性能，在与从入口到出口在不同条件下在通道中消耗的细菌相同的持续时间下进行了芯片外实验。流量。我们还执行了 COMSOL 多物理场程序模拟，以进一步评估应用参数的影响。结果，我们发现结构和流速不会影响所有研究通道类型中的全部裂解，但是与进行的片上和片外样品相比，室温下的片上实验产生了更有效的裂解在较高温度下。有趣的是，在较高温度下的芯片上实验不会导致有效的裂解。