|
|
|
 |
Magnetic Devices for High Throughput Biological Analysis
Thanos Mitrelias
Cavendish Laboratory, Cambridge Friday, 22 Jun 2007, 14.00, W2.19 Microarrays and microbead-based technologies have attracted significant interest in the last few years for their broad applications in the medical diagnostics and high throughput molecular biology areas. However, both technologies have limitations due to their fundamental principles of operation. The throughput of microarrays will always be limited by the array density, while bead-based technologies offer a conceptually different approach due to their ability to extend the detection capability by expanding the size of the chemical library (probes), but are currently limited by the number of distinct codes the beads can carry. We are developing a novel biosensor based on magnetic labels that can be remotely encoded and decoded as they flow in microfluidic channels, by means of an external magnetic read/write head. The microlabels consist of a substrate and magnetic microbars that are individually addressable by the external magnetic device and can be functionalized with various chemical or biological probes. We present data demonstrating the reading of individual magnetic microbars from several samples, one comprising 50x50 microns Co/Au/NiFe/Au elements, another comprising 13x5 microns Ni elements and others comprising magnetic nanowires 200 nm in diameter. The samples are prepared by electrodeposition or photolithography and read by a micro-fluxgate magnetic sensor set up for vertical field detection. The microbars are deposited on a Si substrate and the magnetic signal can be obtained from a sensor-sample distance of 40 to 100 microns. The Au capping layer provides the chemical base for the functionalisation of the microlabels. For instance an HS-C10-NHS self assembled monolayer can be used as a spacer for the attachment of NH2 modified oligonucleotides. The design principles of a novel magnetic biosensor, integrated with microfluidics, that encodes/decodes the magnetic microlabels and that can be used for various applications, such as genome sequencing, immunoassays, proteomics and medical diagnostics will also be discussed. |
||
|
|