Magnetism aids detection of DNA sequences
Cystic fibrosis (CF) is caused by a quarter-of-a-million-base-pairs long recessive gene, on chromosome 7. According to some researchers, there are at least 900 known mutations for the gene. Not surprisingly, the effects on the individual, or its phenotype, vary with the mutation in question. The aim of CF-CHIP project, funded by the EC, was to help unravel the vast range of mutations and phenotypes. Accordingly, they developed a sensor platform composed of an electronically addressable microarray of magnetic spin valve sensors. The main innovation feature was the integration of magnetic sensors to detect the presence of target DNA sequences labelled with magnetic beads. When the complementary sequence hybridises, the bead is immobilised which causes a detectable change in voltage. Consequences of these innovations are that the whole process is accelerated and that the device is portable as the sensors are in the platform biochip. This technology has been demonstrated with polymerase chain reaction amplified DNA including different sequences to identify a mutation in the CF gene. As a result of this development, two patent applications were made and the results have been published in peer-reviewed journals. Due to its portability, it is seen as ideal for use at the point-of care situation. Furthermore, it is hoped that it will provide the basis for sequencing other complex mutations.
