The magnetic sensor platform comprised an electronically addressable microarray of spin valve (magnetic) sensors. Capture DNA (i.e. short oligonucleotides probes with specific sequences) immobilised on top of the sensors hybridise to complementary sequences on target DNA labelled with paramegnetic beads, thereby immobilisiing the beads on top of the sensor. In the presence of an external magnetic field, the magnetic field from the paramagnetic beads induces a change in the magnetoresistance through the sensor, enabling the immobilisation of complementary DNA to a specific sensor to be detected as a change in voltage.
The sensor platform can enable detection of a single 1 micron paramagnetic bead, however, sensing has also been successful with 250nm beads. Application of this technology to detection of PCR amplified DNA has been demonstrated, including differential hybridisation across different sensors with sequences designed to identify a mutaion in the CFTR gene.
IP associated with this technology has been the basis for two patent applications, and some of the researrch results have already been published in peer-reviewed journals.
The key innovative feature of this technology is the combined use of magnetic fields and magnetic sensors, to localise a magnetic bead labelled target analyte adjacent to capture molecules and to detect the presence of a magnetic bead labelled target molecule using the integrated magnetic sensors respectively. Therefore, in addition to accelerating the hybridisation / conjugation reaction, the fact the sensors are integrated in this biochip platform, means that there is no need for additional sensing instrumentaion. It is therefore highly compatible with point of care applications.