Abstract
Automation of sample preparation using a customized TECAN GENESIS Workstation is helping Zeneca to speed up its process of drug discovery, giving new potential for faster and more profitable pharmaceutical marketing.
Zeneca Pharmaceutical's Immunology Group is actively supporting drug discovery in a range of human diseases including cancer, cardiovascular and infectious diseases.
Initial work to automate the group started four years ago and was enhanced in 1997 with the installation of the TECAN GENESIS Workstation. This was customized to the specifications of the team, with the addition of incubators and microplate storage hotels.
Prior to this, some of Zeneca's assays were performed using TECAN Robotic Sample Processors 5052 and 5072 stand-alone liquid handling systems.
Why automate?
Automation of the group's processes was driven by a need for higher throughput and better quality results. Accuracy was the chief concern in selecting the new equipment.
Automated handling routinely improves confidence in results, both because the robot is more precise and because no errors are introduced. There is a potential for errors when human operators are faced with a repetitive pipetting task.
The GENESIS Workstation saves on human resources and makes laboratory scientists' work more interesting. Researchers spend more time profitably and productively, planning and assessing assay results and supporting the information technology needs of the robotic system, rather than taking the part of highly paid automation themselves.
Sample preparation
The GENESIS Workstation is currently used by Zeneca to dissolve compounds. Medicinal chemists send compounds to the project teams via Zeneca's dispensary in pre-barcoded bottles. These are loaded onto the GENESIS'S worktable and the software calculates the correct amount of liquid to produce a defined molarity which is added to each bottle. The solutions are then incubated, dispensed into microplates or diluted for further use.
The group uses the optional carbon-impregnated disposable tips for its work, since there is concern that some compounds could stick to fixed tips, causing carryover into the next well or tube. Residue can be removed from fixed tips with a hazardous hydrochloric acid wash but this was not a practicable long-term solution for the Zeneca team because of the health and safety risks involved.
Assay development
Like many others within Zeneca, the Immunology group works under considerable time pressure to validate primary screening results and finds the GENESIS Workstation saves a great deal of time. The group is also starting to use the GENESIS Workstation to develop secondary screening assays under the leadership of Dr Tang.
Several projects have as an initial test an ELISA-based kinase assay to test for phosphorylation of target peptide substrates. The kinase used is a recombinant, expressed from either specially designed baculovirus or E. coli based systems which Zeneca produces for itself.
The assay is easy-to-use and is fully automated from start to finish. The test compounds are pipetted into 96-well microtitre plates which are pre-coated with a substrate peptide.
The recombinant kinase with additional reagents is added to the microplate and the reaction is incubated for 1 hour at 25°C. The GENESIS Workstation is fitted with a Robotic Manipulator (RoMa) arm which moves plates away from the pipetting area so that the next assay can be started. The RoMa arm and pipetting systems work independently, increasing workflow by ensuring that the system is never idle.
Plates are washed by the automated Columbus washer. A primary monoclonal antibody specific for phosphorylated proteins is pipetted into the microplate wells. This is incubated for 1.5 hours at 25°C.
After a further washing step, a secondary antibody specific for the primary antibody is added and incubated for 1.5 hours at 25°C. The secondary antibody has a horseradish peroxidase (HRP) enzyme attached to it, and is used for detection. An HRP substrate tetramethyl benzidine (TMB) is dispensed. TMB is the substrate of choice because the reaction can be easily stopped. This prevents a drift in results while the plate is being read. Microplates are transferred to a TECAN SPECTRA plate reader where they are scanned at a wavelength of 450nm. The results are automatically transferred to a linked computer system for additional manipulation.
The results of the assay screens are either returned to the chemists for compound modification or, in the event of any potential targets being identified, go on for toxicology studies.
The group is now planning to expand and buy a further system which will be dedicated to bulk handling for high-throughput screening. We also want a system to integrate a cell harvester and CO2 incubator, to give the laboratory even greater automation capacity.
Investing in the future…
Automating a laboratory can mean investing a lot of time. Prior to selecting our TECAN system, the Zeneca team reviewed competing robotic systems from five manufacturers. The two key reasons for choosing the GENESIS Workstation were its flexibility and the fact that the system can be used continuously because the liquid handling systems and the RoMa arm work independently.
Service and support were other important considerations for Zeneca. TECAN provide the team with good technical support for software and helped to develop a number of custom applications, such as compound solubilization. TECAN also offered Zeneca advice on choosing the correct system hardware.
Fully automating Zeneca's laboratory with the GENESIS Workstation has achieved higher throughput and accuracy.
The last few months have seen the GENESIS Workstation overcome many of the group's problems. It prepares more samples, processes more assays, and assays which were too long for a working day can also be carried out.
Zeneca has seen an increase in accuracy and are now looking at using a similar strategy to automate all its assays.
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