Research Of High Purity And High Viability Cell Separation Of A Jakobid Flagellate Based On Soft Inertial Force

Cell separation is one of the key limiting factors for precise analysis of non-axenic microbial lab cultures or environmental samples.Although varied technologies have been developed,it remains a challenge to obtain target cells with high purity and viability via high-throughput cell sorting.In the past decade,hydrodynamic microfluidic platforms have attracted great attention in cell preparation due to their high efficiency,robust performance and low cost.Due to bacteria-like Jakobid mitochondrial DNAs,obtaining Jakobid flagellates with high purity and high viability is a good way to understand the origin of eukaryote-defining organelle.Therefore,we fabricated a kind of microfluidic separation chip to obtain a kind of bacterivorous Jakobid flagellate from live bacteria.In this study,we employ the use of a low-velocity sheath flow with high viscosity and a high-velocity sheath flow with low viscosity.The sample flow is wrapped by these two sheath flows at the intersection in a soft inertial separation chip.By using this method,a large shear rate is generated which significantly increases the deflection of large cells away from the sample flow while smaller ones keep moving together with sample flow.After building simulation models,the feasibility of this chip has been proved by experiments on a mixture of small and large fluorescent particles(1.0 and 9.9 mm,respectively).Then,the experimental conditions,including viscosity,flow rate and chip design,have been optimized for Jakobid cells separation.Over 98% of bacteria have been successfully removed and collected Jakobid cells show high viability.When the tests results are compared with that of other traditional and extensively used methods(e.g.flow cytometry),our chip showed more than 40% higher separation efficiency and higher viability.Thus,our device proves high purity and viability for cell separation of a sensitive cell sample with asymmetric morphology.In Potential,this method could be further used for more extensive applications,such as disease diagnostics and analyses of mixed microbial samples from our environment.