Chip-based lab cuts PCR time
could reduce the time it takes to carry out the DNA amplification
required for polymerase chain reactions to five minutes.
PCR is a method for enzymatic amplification of a specific DNA sequence of interest. This technique is capable of amplifying a sequence 105 to 106-fold from tiny (nanogramme) amounts of DNA from a mixed sample, such as might be found in genomics studies.
Conventional methods require approximately two hours to carry out 30 amplification 'cycles', although Roche has slashed this to 15 minutes using its LightCycler system family. And in time, IMM hopes to improve the performance of its prototype to allow 20 cycles in just two minutes.
The Institut fur Mikrotechnik Mainz (IMM) unveiled the prototype at the Analytica 2004 meeting, which comes to a close today. Starting from a purified DNA sample, the system will deliver a droplet of amplified DNA in five minutes, which can then be transferred by pipette for further analysis.
A spokesman for the IMM told DrugResearcher.com that Evotec Technologies, a partner in the design project, has developed a system that allows a rapid automated process for analysis integrated within the chip, making a gel electrophoresis step redundant.
He also noted that the modular design of the chip means that it may be possible to link a series of chips in sequence, with each set up to carry out a specific function. In this way, for example, a droplet of blood could be placed into the system at one end, and undergo a series of process steps (e.g. sample preparation, metering, mixing, biochemical reaction, and analysis), giving a readout at the other. And the tiny amounts of reagents used in the system should lead to reduced consumable costs.
The chips are connected by capillary systems , and transportation of the fluid volumes (in the nanolitre range) is carried out by micropumps developed at IMM. These micropumps, which use magnetism to propel the tiny fluid volumes, allow measuring and mixing of fluids without trapped air in the chip's channels.
IMM has been responsible for developing and designing the fluidic system and is testing the prototype, while Evotec has been developing the specific PCR application. The aim in time is to incorporate an integral tool for analysis, combining a laser with microscopy to detect a fluorescence signal.
The spokesman said that additional development would take around nine months to complete, with R&D institutions approached to use it as a development tool thereafter. In around five years' time, IMM plans to have a finished version ready for sale to clinical labs, hospitals and industry.
