Droplet CAR-Wash: continuous picoliter-scale immunocapture and washing

Abstract

The CAR-Wash provides >100-fold dilution with >98% magnetic bead recovery for washing picoliter-scale droplets at 500 Hz.

On-chip background dilution in droplets with high particle recovery using acoustophoresis

“…This limitation can be solved by controlling the position of the particles during the droplet split, and the most common way to achieve droplet washing with high particle recovery is by magnetophoresis 11–14 . For example, Pan et al 11 showed a system with two droplet injection units combined with three droplet splits and applied the system for DNA extraction, and Doonan et al 14 showed another type of on-chip droplet washing system also using magnetic forces. Magnetic methods are generally simple to operate but have a limitation that they only work with magnetic particles or with magnetically labeled samples.…”

Electrokinetic Desalting and Salting of Water-in-Oil Droplets

“…15 In the droplet CARwash (coalesce-attract-resegment) technique, developed by the Bailey group, the droplet media can be exchanged with the retention of encapsulated particles such as magnetic beads without compromising throughput. 16 The droplet CAR-wash technique is useful for on-chip buffer exchanges and rinsing − two steps that are extensively applied in biochemical assays involving the capture, modification, and analysis of solid particles. However, control over the extent of reagent (or buffer) exchange is limited in the droplet CAR-wash technique.…”

“…Niu et al developed a microdroplet dilutor for high-throughput screening that utilizes droplet merging, mixing, and resplitting for controlling the droplet concentration . In the droplet CAR-wash (coalesce-attract-resegment) technique, developed by the Bailey group, the droplet media can be exchanged with the retention of encapsulated particles such as magnetic beads without compromising throughput . The droplet CAR-wash technique is useful for on-chip buffer exchanges and rinsing – two steps that are extensively applied in biochemical assays involving the capture, modification, and analysis of solid particles.…”

Microfluidic SlipChip device for multistep multiplexed biochemistry on a nanoliter scale

“…), especially when there are multiple steps. 6,[8][9][10][11][12][13][14] Although droplet-encapsulation methods 15 provide virtually unlimited scalability to the number of compartments, and have progressed greatly in high-throughput detection, [16][17][18] washing, 19 and sorting, 20 they have limitations with respect to reagent additions to the originally encapsulated volumes, imaging, and reaction parallelization.…”