Figure 1. Microfluidic device for automated NGS library preparation.

(a) Automated multi-column device mounted on a plastic carrier that provides wells for loading samples and reagents and for pressurized operation of the device. The wells used to load reagents for NGS library preparation are labeled. Chromatography columns for the selective binding and release of DNA were formed either with ChargeSwitch beads or with carboxylated beads. Reagents that were used exclusively with the carboxylated beads are labeled in green. (b) Schematic of single reactor unit for reaction mixing and DNA purification. The regions denoted in the reaction circuit are as follows: Green, Sample; Orange, Buffer; Blue, Enzyme. Red solid rectangular boxes represent activated valves that partition the individual circuits. (c) Parallelization of 16 reactors on chip for preparation of up to 16 independent libraries. Layout of the entire device without the valve map showing reagent inlets and the design for multiplex library generation. The serpentine metering channel designed to ensure reliable column packing is highlighted in orange. (d) Schematics showing cross-sections of purification columns loaded with either 1) ChargeSwitch beads, which are held in place with a frit layer and a cap layer formed by larger beads, or 2) carboxylated beads.