Microfluidics based bioimaging with cost-efficient fabrication of multi-level micrometer-sized trenches

Microfluidic devices, through their vast applicability as tools for miniaturized experimental setups, have become indispensable for cutting edge research and diagnostics. However, the high operational cost and the requirement of sophisticated equipment and clean room facility for the fabrication of these devices make their use unfeasible for many research laboratories in resource limited settings. Therefore, with the aim of increasing accessibility, in this article, we report a novel, cost-effective micro-fabrication technique for fabricating multi-layer microfluidic devices using only common wet-lab facilities, thereby significantly lowering the cost. Our proposed process-flow-design eliminates the need for a mastermold, does not require any sophisticated lithography tools, and can be executed successfully outside a clean room. In this work, we also optimized the critical steps (such as spin coating and wet etching) of our fabrication process and validated the process flow and the device by trapping and imaging Caenorhabditis elegans. The fabricated devices are effective in conducting lifetime assays and flushing out larvae, which are, in general, manually picked from Petri dishes or separated using sieves. Our technique is not only cost effective but also scalable, as it can be used to fabricate devices with multiple layers of confinements ranging from 0.6 to more than 50 $$m, thus enabling the study of unicellular and multicellular organisms. This technique, therefore, has the potential to be adopted widely by many research laboratories for a variety of applications.