Automated Microfluidic Screening Assay Platform Based on DropLab

摘要

This paper describes DropLab, an automated microfluidicnplatform for programming droplet-based reactions andnscreening in the nanoliter range. DropLab can meternliquids with picoliter-scale precision, mix multiple componentsnsequentially to assemble composite droplets, andnperform screening reactions and assays in linear or twodimensionalndroplet array with extremely low sample andnreagent consumptions. A novel droplet generation approachnbased on the droplet assembling strategy wasndeveloped to produce multicomponent droplets in thennanoliter to picoliter range with high controllability on thensize and composition of each droplet. The DropLab systemnwas built using a short capillary with a tapered tip, ansyringe pump with picoliter precision, and an automatednliquid presenting system. The tapered capillary was usednfor precise liquid metering and mixing, droplet assembling,nand droplet array storage. Two different liquidnpresenting systems were developed based on the slottedvialnarray design and multiwell plate design to automaticallynpresent various samples, reagents, and oil to thencapillary. Using the tapered-tip capillary and the picoliterscalenprecision syringe pump, the minimum unit of thendroplet volume in the present system reached ∼20 pL.nWithout the need of complex microchannel networks,nvarious droplets with different size (20 pL-25 nL),ncomposition, and sequence were automatically assembled,naiming to multiple screening targets by simply adjustingnthe types, volumes, and mixing ratios of aspirated liquidsnon demand. The utility of DropLab was demonstrated innenzyme inhibition assays, protein crystallization screening,nand identification of trace reducible carbohydrates.