Laser-powered turbo PCR
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- GNA Biosolutions provides the required reagents and DNA-coated gold nanoparticles in cartridge form. Source: GNA Biosolutions
16.12.2014 -
Since its development more than 30 years ago, the technique of polymerase chain reaction (PCR) has asserted itself as one of the most important standard methods in biotechnology. This is used to increase the amounts of specific individual DNA segments or small quantities of DNA. As part of the funding initiative SME Innovative from the Federal Ministry of Education and Research (BMBF), the company GNA Biosolutions has developed a new ultra-quick technique that massively accelerates the step of DNA amplification. Rather than hours, this so-called Laser PCR takes just 15 minutes.
1983 was the birth year of polymerase chain reaction. The principle behind the method is little changed in the decades since its invention, namely clever temperature control and the use of specific molecular tools, which enables the reproduction of DNA. “Although only a few DNA molecules actually require warming, it has always been necessary to heat the entire reaction liquid,” says Joachim Stehr, head of research at biotech company GNA Biosolutions. Although the warming and cooling takes only a few seconds in classic PCR, it is because this step is repeated dozens of times that the process becomes protracted.
The company in Martinsried has now managed to massively accelerate the standard PCR process as part of a project within the funding measure SME Innovative. Thereby, the BMBF is supporting the development work with around 300,000 euros. “All of the liquid is kept at a constant temperature. Using short laser pulses, we heat gold nanoparticles on which the DNA segments are attached,” says Stehr of his Laser PCR method. The short heating of nanoparticles – just a few microseconds – functions around a million times quicker than the previous approach of fully heating the liquid. The entire process can be completed in around 15 minutes, say GNA Biosolutions.
Saved time can save lives
For the scientific research community, the time savings is most likely to be reflected in higher levels of comfort: Instead of waiting for results, it will be possible to immediately plan new laboratory experiments. In medicine, the saved time could, in extreme cases, mean the difference between life and death – for example in the diagnosis of sepsis. When using classical cell cultures to detect pathogens, doctors must currently wait one or two days for the results of an analysis – far too long if the mortality rate of a life-threatening disease rises with every passing hour. Ultra-fast PCR analyses could deliver results within minutes.
GNA Biosolutions originally emerged as a spin-off from the Department of Photonics and Optoelectronics at Ludwig-Maximilians University in Munich. The Federal Ministry of Economics provided support with funding from the EXIST Research Transfer program. “The initial idea was to investigate whether it is possible to measure the heat generated by the laser in the environment around the nanoparticles,” recalls co-founder Stehr. Because DNA molecules have a well-defined melting point, the physicists used them as a molecular thermometer. “When nanoparticles bind to DNA molecules, they change their optical characteristics. This can be exploited for ultra-quick detection of DNA,” explains Stehr.
This method of detection, which is known as Nanostove, ultimately led to the idea for Laser PCR. In the future, the two systems may also be offered in combination: Firstly, rapid DNA amplification via Laser PCR, then the targeted detection of selected genome fragments using Nanostove technology. Bringing the process to this level of maturity will take some time, however. Even if GNA Biosolutions can greatly accelerate DNA amplification, in terms of research and development, the Martinsried-based scientists are forced to work at the same speed as everyone else.
Market launch planned for 2015
Laser PCR is not available at this time.“ We want to begin commercialisation in 2015,” says Stehr. The preferred approach will be to offer the method as a complete system, which should ensure consistently high quality. Thereby, a specially constructed device that includes the laser will replace the standard thermal cycler. GNA Biosolutions will provide the required reagents and DNA-coated gold nanoparticles in cartridge form. Among other uses, this could be employed to detect hospital-acquired infections or antibiotic resistance.
