It’s Not Only About Throughput

Automated liquid handling (ALH) grew from the highthroughput needs of medical diagnostic labs in the late 1980s through the 1990s and then received an additional boost from genomic sequencing. As it evolved from a specialized, expert-driven instrument system to a generalized laboratory workstation, ALH has become more accessible to more workers in more labs.

Automation vendors have achieved this despite the uniqueness of ALH workflows. ALH is not a point and shoot technique like spectroscopy or analytical chromatography. Every ALH experiment is unique in terms of reagents, volumes, order of addition, target analyte, and readout.

Speed is the most-cited advantage of ALH compared with manual pipetting, but as we will see, pipetting accuracy and freeing lab workers from monotonous pipetting are valued at least as highly as throughput. Depending on the number of samples a lab typically runs, the business case for acquiring or upgrading an ALH system may be based on throughput, quality, operator time savings, or some combination of the these factors.

Accuracy provides an additional, independent cost-saving benefit. ALH can ensure the accuracy of ultra-small volume dispensing, which is a principal factor in minimizing assay, reagent, and disposal costs. Microliter-size assays are now routine, with PCR often employing nanoliter or picoliter reaction volumes and microarraying striving for femtoliter dispensing. Reduced volumes increase an assay’s volumetric complexity, which in turn raises the standard for accurate pipetting.

Assay miniaturization has spilled over into instruments and components as well. “Lab space is limited, and the less space taken up by instrumentation, the better,” says Merja Mehto, product manager for automated liquid handling products at Thermo Fisher Scientific (Vantaa, Finland). This has led vendors to devote significant design resources to creating liquid handlers that are scalable, compact, and easy to use.