Why Do I Need an Automated System?
Below is an overview of liquid handling automation technology and what to expect while carrying out an automation project.
What to Expect from Automated Systems
- When you automate your assays, you will be able to increase process reproducibility and many cases the throughput in your laboratory.
- An automated process will also free you or your staff from time-consuming repetitive tasks to have more time for creative thinking.
Limitations of Automated Systems
- Automated systems will not automatically improve the quality of pipetting and yield. Only in the case of a well-defined assay with a protocol that is well adapted to the automated process, yield can be expected to be equal or better than in the manual process.
- Some assays require manual steps that require close eye-hand interaction: e.g. moving the tip of a droplet and aspirate following the droplet. In other words: mimicking complex manual processes can be a challenge – even with HAMILTON’s technology that is using advanced monitoring features to imitate such manual operations.
Automated Systems, How to Define Your Project Requirements
The requirements for the system are discussed as regards to:
- the stepwise analysis of the assay protocol
- throughput and storage capacity: this also includes your walk-away-time requirements. Depending on these requirements e.g. deck space / storage space needs to be selected.
- type of samples and reagents: liquid volume and characteristics of certain liquids (e.g. highly viscous liquids) influence the pipetting behaviour and thus the configuration of the instrument regarding pipetting units or specific pipetting parameters.
- type of labware used: labwares are plates, tubes etc. used on an automated system. Some labwares are easy to handle and others are difficult to handle on an automated system. Choice of appropriate labware is essential for a successful automation project.
- degree of automation: The 80/20% rule: Be sure about the most reasonable and efficient degree of automation: The last 20% to full automation may have a significant impact on project costs.
- space requirements: automated systems need certain amount of space like any other instrument. Such systems also have additional need for electrical drops, gas inlets, vacuum outlets and other specific requirements depending on your assay, which may call for lab-space renovation.
- user interface: you may want to give different users different access rights to methods - or you may want to define a specific error handling. In addition, you might want to have an easy-to-use user interface for simple user intreraction. Such requirements have an influence on method development and on costs.
- data handling: any automated system made for handling large amount of assay plates, with each plate undergoing complex requires an underlying sophisticated data tracking capabilities. Data should be readily available and easy to share. There may be additional requirements such as a connection to a LIMS system requiring specific interfaces.
At HAMILTON, we use a standardized application checklist to record the initial user requirements. You may use this checklist for your project. The list can be downloaded as a PDF file or Read-Only Word document.
Liquid Handling Workstation Architecture
- Most liquid handling workstations have a similar hardware architecture. They consist of:
- a deck which is the workbench, where labware with reagents and samples are placed
- a pipetting arm that holds the actual pipetting units. The arm moves across the deck so that the pipetting units can reach the labware.
- pipetting units do the actual pipetting. There are individual pipetting units as well as pipetting “blocks” in 96-well format and even 384-well format
Pipetting Principles in Automated Liquid Handling
Air Displacement Technology is the latest technology currently used in liquid handling workstations. It imitates the operation of an electronic hand-held pipette. The system is free of system liquids, tubing, syringes and valves. The advantages are obvious: cross-contamination or dilution effects caused by system liquids can be eliminated. The technology allows monitoring of each pipetting step (e.g. clot detection) as well as detection of liquids levels using pressure sensors. In addition, a wide volume range can be covered just be using different tip sizes - but without the need for any manual changes to the configuration. Monitored Air Displacement Technology is the main pipetting principle used in HAMILTON’s STAR workstations.
Positive Displacement Technology uses disposable plastic miniature syringes. The advantages of this technology are contamination-free and aerosol-free pipetting. The limitation of the system is that plates with smaller wells (384 or 1536) cannot be accessed and the limited tip capacity of 300ul. This technology is used on HAMILTON’s ATplus2 workstation.
Liquid-Filled Systems are based on diluter technology. They consist of automated syringes, valves, tubing and needles. The advantage of this technology is a good performance over a wide volume range. However, manual changes to the configuration (syringe/needle sizes) are needed, to adapt the instrument to a different volume range. The limitations of this technology are the risk of cross-contamination and dilution effects caused by system liquids. Maintenance can also be more complicated, since regular change of tubing/liquid is needed. This technology is still used by many manufacturers – including HAMILTON’s MICROLAB 4000 and 4200 workstations.
Automated Systems - Software
Existing software packages for the programming of liquid handling workstations are based on a 2-step approach:
- First, define what is available in terms of labware for the task, and its location on the deck. This is called “creating a deck layout”.
- The second step is then to do stepwise programming of liquid transfers, based on the defined deck layout. This may be done in single steps (one transfer) or using compound commands comprising, e.g., all pipetting steps to fill a complete plate.
Some manufacturers also offer a scheduler, which does the automatic planning of resources for multiple parallel processes running on the system.
Automated Systems - Complete Integration Solutions
In some cases, an automation project involves more than liquid handling – it may include the integration of additional instruments for analysis. Read more about what HAMILTON can offer in this field.