Nanoliter Liquid Transfers with Tecan’s Freedom EVO®

Using the Freedom EVO® workstation’s MultiChannel Arm™ 384, the University’s Screening Center has achieved reliable liquid transfers down to just 80 nanoliters. Silke Müller, a biologist in the screening facility, explained: “We work with a wide range of samples – enzymes, mammalian cells, bacteria – using various high throughput screening assay formats according to the needs of individual research groups. Our Freedom EVO therefore needs to be very flexible in the types of assays we can perform.”

With a library of over 38,000 compounds for screening, the center wanted to avoid the need for wasteful pre-dilution of stock solutions to enable large-scale studies to be performed more cost-effectively. Silke continued: “The minimum transfer volume specified for the MCA 384 is 500 nl, but we needed to achieve reliable transfer of just 80 nl of liquid to meet our target final concentration per well. Using fixed steel tips, I developed a technique similar in principle to a pin tool device, relying on the residual liquid volume on the inside and outside of the tips following several aspiration and dispense cycles to provide very low volume transfers. Although the exact aspiration/dispense volume and number of cycles needs to be optimized for each assay buffer, this method has proved highly reliable, with CVs of ~10 % for 80 nl transfers.”