Automation of high-throughput arrayed lentivirus production and titration

Abstract

Generation of arrayed genome-wide CRISPR libraries in a ready-to-transduce lentiviral format remains laborious, time-consuming, and costly. To address these limitations, the present study developed a fully automated lentivirus production and titration workflow using a Biomek i7 Hybrid automated workstation, integrated with multiple instruments and managed by SAMI EX software. The workflow produced and titrated viruses in 96 and 384-well plate formats, respectively. It employed reverse transfection and triplicate wells per lentivector to reduce variability and yielded an average of three viral particles in transduction unit (TU) per producing HEK293T cell. Titration was performed using U937-mCherry suspension cells, with the percentage of transduced cells converted from U937 (X%) to HEK293T (Y%) values via a linear regression equation (Y% = 4.3X% + 9.3%). The titer calculation was based on the initial seeding cell number, the converted percentage of HEK293T transduced cells, and virus input volume. The titration demonstrated strong reproducibility across LSRFortessa (BD) and Aurora (Cytek) flow cytometers (R2 = 0.9). Among 1,760 unconcentrated virus preparations, median and mean titers reached approximately 1.2 x 106 TU/mL, with over 97% of samples exceeding the high-titer threshold of 2x105 TU/mL, thus demonstrating a robust, scalable, and cost-effective automation platform for high throughput arrayed lentiviral library production and titration.