by Sikander Gill, Rajwant Gill, Nick Bandy and Dong Liang

Reduced costs and higher throughput have made next-generation sequencing (NGS) more accessible to users in such diverse fields as diagnostics, infectious disease, food safety and public health. Increased capacity has created a challenge: establishment of an automated library preparation workflow to enable reliable and robust sequencing. Magnetic beads play a significant role in many steps of NGS library preparation, highlighting the need for their uniform distribution. Here we demonstrate an efficient bead mixer placed on the deck of a robotic workstation to keep the beads uniformly suspended during distribution. Beads were mixed by the on-deck magnetic bead vortexer and distributed to a 96-well plate containing 1xPBS for measurement by spectrophotometer. It was observed that vortexing during distribution gave very uniform distribution of magnetic beads across all wells; correlations of libraries prepared by the VERSA automated workstation were very highly correlated with libraries prepared manually (Pearson’s r² > 0.990). The magnetic bead vortexer provides highly consistent bead distribution during library preparation representing a significant improvement to current automated protocols.