Abstract

Automated Droplet-Based Microfluidic Analysis and Screening with Sequential Operation Droplet Array System

Qun Fang, Professor, Zhejiang University

Recently, on the basis of the DropLab systems built by the authors’ group [1, 2], we developed a sequential operation droplet array (SODA) system for performing fully-automated and flexible droplet manipulation, analysis and screening with picoliter-scale precision [3]. The SODA system was built using a tapered capillary-syringe pump module and a two-dimensional (2D) oil-covered droplet array installed on an x-y-z translation stage. With the SODA system, we developed a novel automated droplet manipulation method with picoliter precision using the programmable combination of the capillary-based liquid aspirating-depositing and the moving of oil-covered 2D droplet array, so-called “aspirating-depositing-moving” (ADM) method. This method could automatically achieve multiple droplet manipulations including droplet assembling, generation, indexing, transferring, splitting and fusion, and has advantages of ultralow sample/reagent consumptions and good versatility and flexibility in analysis and screening for multiple different samples. We applied the SODA system in enzyme inhibition assays, protein crystallization screening and single cell analysis. In the enzyme inhibition assays, the consumptions of samples and reagents are only 60–180 pL for each droplet microreactor, which are commonly 3–5 orders of magnitude lower than those of conventional multi-well plate systems.