South Korean scientists have used fluorescence resonance energy transfer (FRET) to detect DNA hybridisation in a microfluidic channel.

Jaebum Choo of Hanyang University and colleagues have developed a quick and accurate way of analysing DNA hybridisation, a technique used in the detection of genetic diseases. A microfluidic device is used for hybridisation and FRET is employed for detection.

DNA hybridisation is used to detect and measure the presence of similar DNA sequences. Separated single DNA strands from different DNA sources are allowed to form a new hybrid. The stability of the hybrid also gives information on how similar the DNA strands are.

Choo said that microfluidic technology for DNA hybridisation has several advantages over the more commonly used microarray method. First, hybridisation occurs in a much faster time (only a few seconds, compared with one or two hours for the microarray procedure). Second, a syringe pumping system is used to inject the target and probe DNA solutions, a less expensive method than the immobilisation procedure used in the microarray technique.

The team used FRET to overcome a drawback of detecting hybridisation in the channel, according to Choo. Non-hybridising fluorescence-labelled oligomers cannot be removed from the channel, which means that the hybridising and non-hybridising DNA oligomers cannot be distinguished. 

'In order to resolve this problem,' said Choo 'we labelled both the probe and target DNA oligomers with different fluorescence dyes. One is working as a fluorescence donor and the other is working as an acceptor.' When the DNA oligomers hybridise, the distance between the two fluorophores on the new DNA hybrid is near enough for FRET to occur, enabling DNA hybridisation to be measured.

Choo said that the team hope to develop their technology further in the field of high-throughput screening of DNA hybridisation. 'Our technique addresses the continuing need for a rapid and inexpensive method for hybridisation-based investigations into single nucleotide polymorphism,' said Choo.

Katherine Davies