Handle with care

High throughput (HT) technologies now play a vital role in many areas of research where success depends on the evaluation of large numbers of samples. Here, Geoff Simmons tells us how liquid handling is key to HT success

THE Centre for Materials Discovery (CMD), within the University of Liverpool’s Department of Chemistry, is a newly opened facility where high throughput techniques are being applied to research on biomaterials, polymers, household products and nanotechnology. In order to accelerate and standardise the pipetting steps necessary before various analyses, an automatic liquid handling system was required. Based on the CMD scientists’ extensive experience with laboratory automation, it was established that the automated system needed to provide rapid processing speed, high-precision pipetting of volumes from 1µl to 1ml, straightforward serial dilution methods, and data transfer options.
Dr. Neil Campbell, senior experimental officer at the CMD, explains their purchasing decision: “We came to the conclusion that we could automate complex pipetting steps more quickly and simply with Eppendorf’s epMotion liquid handling platform than with any other system. I was particularly interested in the optical sensors for liquid level detection, and the fact that epMotion has the flexibility and functionality of much larger robots but in a small, affordable box. The very low error rate and high reproducibility, plus the availability of the PC version with improved data transfer, led to us purchasing an epMotion 5075 LH, initially for speeding up surface tension measurements of compounds and formulations.”
Understanding the surface tension properties of aqueous surfactants and polymer materials is crucial in the development and production of compounds as diverse as pharmaceuticals, inkjet printing inks and shampoos. However, the traditional manual method of measuring surface tension is very time-consuming and only a few compounds can be measured by one person each day. CMD scientists have successfully developed a generic process for high throughput measurements using an Eppendorf epMotion in conjunction with a Kibron Delta-8 high throughput surface tensiometer.
Up to 24 samples of polymers or surfactants are placed directly onto the epMotion deck, in 0.5 ml, 1.5 ml or 2 ml centrifuge tubes, for preparation of serial dilutions in a 96-well plate using an aqueous medium. A daughter plate is then produced using a Teflon-coated Kibron screening plate, which allows the retention of a droplet-shaped meniscus onto which the eight probes of the Kibron Delta-8 make contact.
According to Dr Campbell: “The superb pipetting precision of the epMotion drastically simplified uniform loading of the screening-plates, which had been very difficult to achieve manually. Our high throughput method is also hundreds of times faster, with manual throughput only one sample per hour could be processed, while using the epMotion as many as 24 samples in 11 different concentrations can be measured in one hour, with a high degree of accuracy and reproducibility. Another immediate advantage of the automated system is the cost saving from a significant reduction in sample volumes.”
Two values are calculated for each sample: the air-water partition coefficient, a useful measure of hydrophobicity/hydrophilicity, and the critical micelle concentration. This a key parameter for the optimisation of aqueous formulations in a wide range of industrial sectors as it calculates the critical concentration at which amphiphiles associate into micellar structures. Using dilution mediums of different pH the effects of polymer mixtures on surface tension with respect to changes in pH can be investigated. This enables rapid research on selective pH responsive materials, such as polymers used to encapsulate drugs used in various drug release technologies.
Dr Campbell was impressed by the short timeframe with which new liquid handling applications could be developed: “Vessels or microplates do not have to be calibrated before use with the epMotion, as the relevant data on a wide array of plate formats and containers are prepared by Eppendorf and accessible to users over the internet. We can implement new protocols rapidly and the automated recognition of pipetting patterns, 3D simulation and the optical sensor that tests the work table for the correct layout, further increase the ease of use and operational control.”
Having achieved substantial results with high throughput surface tension measurements within only four weeks, the epMotion has become an important tool for automating liquid handling steps in many more techniques and analyses. These include high throughput syntheses and screening the physical properties of materials.
The CMD received funding from industry, the University of Liverpool, the Northwest Development Agency and the Merseyside European Objective One programme – totalling over £8.2 million (€12.4 million). Directed by Professor Andrew Cooper, the CMD has 1,600 square metres of lab space and employs a team of science and business professionals. Providing research facilities and training on HT technologies for many small to medium enterprises on Merseyside and in the surrounding Northwest region, the CMD helps both companies and academic organisations invent materials, develop novel techniques and improve products. The automated pipetting system is contributing significantly to the Centre’s training role, as Dr Campbell explains: “Innovative menus lead new users intuitively through the epMotion software, making the system easy to learn and it has proved to be an ideal teaching tool.”
For the Centre of Materials Discovery, the acquisition of an automated pipetting system has been a key step in establishing high throughput technologies as an integral part of its pioneering materials research. Rapid investigation of industrially viable materials can now be conducted more cost-effectively, reducing the time required to bring products to market.


Geoff Simmons 
Geoff is Brand Marketing Specialist at Eppendorf UK