High throughput cell isolation using post-array microfluidic chip

Abstract

In view of the limitation in forensic DNA analysis where there is currently no established method in isolating and analyzing individual cells within a biological sample, the growing interest in the research of droplet microfluidics in recent years may serve as a promising strategy to overcome this limitation. Droplet-based microfluidics is known for the ability to generate and manipulate micrometer-sized droplets. Leveraging on the advantages unique to droplet microfluidic systems, it is common nowadays to compartmentalizing cell(s) or particle(s) in size-controlled microdroplets to mimic molecular processes or reactions within droplets respectively. As such, using this strategy to isolate individual cells in droplets helps to greatly enhance test sensitivity in forensic analysis. In this project, the effects of varying two critical parameters, inter-post distance (l1) and inter-row distance (l2), of an existing design of post-array microfluidic chip on droplet diameter were studied. Then, fluorescent-labeled cells added to the large and polydisperse crude emulsion, that compose of cooking oil as the dispersed phase and water as the continuous phase, is smaller droplets produced at the outlet. By visual observation, the best chip that had generated most uniform droplets, occupied by cell(s), was with square post-array with l1 at 50 μm and l2 at 20 μm with average droplet diameter at 34 μm.