Pain-free PCR: BJS Biotechnologies creates UF1
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Written by Suzanne Elvidge, Member of the Association of British Science Writers   
Tuesday, 30 November 2010
Laboratories around the world use the polymerase chain reaction (PCR) for a wide range of applications, from isolation of DNA sequences for genetic engineering, through bacterial screening to genetic fingerprinting, to identify people in forensics or to determine paternity.

While PCR techniques have developed extensively since the technique’s inception in the early 1980s, the process has remained slow and the results can be variable. Development of heating techniques such as direct resistance heating is taking PCR to the next level by improving speed and reproducibility.

An introduction to PCR :

Now a routine technique in many labs, in vitro replication of DNA in the early 1970s and the iscovery of the polymerase chain reaction in 1983 created a revolution in DNA quantification and manipulation, with applications from bench research through genetic fingerprinting to diagnosis of disease and monitoring of treatment. ne of the key elements of PCR is thermal cycling, which initially heats the DNA in order to denature the molecule, breaking the strands apart (DNA melting), and creating templates.

The thermal cycler then cools the single stranded DNA, allowing the primers to anneal and DNA replication process to begin, catalysed by the enzyme DNA polymerase. The machine repeats the heating cycle to denature the new DNA molecules and continue the replication and amplification process.

PCR – its perils and pitfalls :

The key issue with the existing thermal cycling technologies used in PCR are thermal uniformity and accurate temperature control, and these are vital for fast and efficient DNA amplification, and accurate and consistent results.

The correct temperature is very important for primer specificity – too high or too low temperatures at given steps, or uneven heating, can lead to non-specific annealing, increasing the time taken for processing, wasting expensive reagents, and potentially leading to inaccurate results.

In most thermal cyclers, the DNA samples are placed in plastic tubes or microtitre plates, and these are heated and cooled using a heat exchange block, generally using the Peltier effect devices. Because of the distance between the samples and the heating element, the DNA amplification process can take up to one or two hours.

A solution – UF1:

“Current real-time PCR thermal cyclers are both expensive and slow. We had become frustrated with the limited power and heat, as well as the lack of thermal uniformity, from cyclers using the Peltier effect,” says Ian Gunter, R&D Director, BJS.

24- and 96-well consumables
Fig 1: 24- and 96-well consumables

Led by Gunter, the BJS research team investigated alternative ways to heat and cool the DNA assays, and finally focused on using the block as a resistance within an electrical circuit to heat and forced air cooling. Direct resistance heating turned out to be faster and more uniform, and in 2004, BJS spun out BJS Biotechnologies to exploit the discoveries.

 
 
Fig 2: UF1 thermal cycler
 
1 UF1, BJS Technologies’ thermal cycler, uses a single low-cost disposable consumable, which replaces the microtitre plate, heat exchange block and heating system. This puts the liquid assays in direct contact with the heating element, allowing faster rates of temperature change and finer temperature control, reducing process time to as little as five minutes for 30-cycle PCR.

“UF1 is around ten times faster than comparable thermal cyclers on the market – this means it could replace duplicate machines in a laboratory, saving on equipment costs and bench space in health and research laboratories,” says Richard Lewis, Managing Director, BJS Biotechnologies.

“The faster results and lower input costs will speed up research, so could mean a faster return on investment (ROI) for commercial laboratories and saving in valuable resources for noncommercial enterprises.”

The technology :
BJS Biotechnologies’ consumable is made up of a thin metal plate with an array of tubes for the assay samples. Currents are passed through the low resistance, ultra thinly plastic coated metal sample plates. Using computer controlled power supplies, currents are passed though the plate at very low voltage ensuring that the system is inherently safe. The UF1 thermal cycler detects temperature remotely using an array of noncontact sensors. The emperatures across the plate are fed back to the power supplies 50 times a second to ensure exact thermal uniformity is achieved across all sample positions. The PCR reaction is monitored using five-colour fluorescence detection.

Fluorescence detection of a dilution seriesFig 3: Fluorescence detection of a dilution series

The plates are available as 24- or 96-well, and are fullyinterchangeable, and use standard 4.5 mm and 9 mm pitches for automated handling. While using disposables may seem wasteful in this era of waste reduction, the single-use plate eliminates the need to use cleaning agents, power and water in the cleaning process, reduces the risk of contamination, and is recyclable. Both the UF1 cycler and the UF1 plates are patentprotected worldwide.

Applications for UF1:

Its process speed means that UF1 has potential in situations needing rapid diagnoses, for example at Point-of-Care in epidemics such as foot and mouth or swine flu, avian flu, or for detecting MRSA infections in hospital A&E settings.
Other applications could include biopsies, detection of bacteria or viruses in biological warfare or bio-terrorism, identification of waterborne disease, and tracking contamination in the food manufacturing industry, as well as pharmacogenomics in personalised medicine.

UF1 will launch at Biotechnical, in Hannover, Germany, in October 2010, where representatives from BJS Biotechnologies will meet with European distributors. It will be available in its first market, the UK, in early 2011, and is expected to sell at a far lower cost than many of the other real-time thermal cyclers on the market. For more details, go to www.bjsbio.com.

About BJS Biotechnologies:
Based in London, UK, BJS Biotechnologies was spun out from BJS Company in 2004, to focus on thermal cycler technology. BJS Biotechnologies is backed by years of expertise in heat exchange and thermal cycling at its parent company, along with cutting edge expertise from its employees and scientific advisory board.

Enquiries to:

Richard Lewis,
Managing Director
BJS Biotechnologies Ltd.
65 Bideford Avenue, Perivale, Greenford, Middlesex UB6 7PP, UK
Tel: +44 (0)208 810 5779 ; Fax: +44 (0)208 810 5883


Ms.Suzanne Elvidge, Member of the Association of British Science WritersAbout Author: Suzanne Elvidge is a freelance writer, who covers the pharmaceutical, biotechnology, contract research, and healthcare industries for a wide range of online and print science and business publications including Windhover’s Start-Up, Nature Biotechnology, and Life Science Leader.
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