Magnetic Field Mediated Collection and Dispersion of Superparamagentic Beads on Micro-Hall Effect Biosensors Using Localized Integrated Field Gradients for Biomedical Applications

摘要

Biosensing platforms based on magnetic labeling with superparamagnetic particles show promise for the manipulation, control and detection of individual biomolecules and cells [1]. There have been reports on the detection of DNA using magnetoresistive (MR) elements, such as spin-valve sensors [2, 3] as well as our group's efforts on the use of high electron mobility, thin film micro-Hall biosensors [4-5] as alternative and complementary biosensing platform. However, irrespective of the type of sensor employed, the detection speed and consequently, the throughput of biosensing systems is limited by the time taken for a given receptor on the surface of the sensor to bind with a specific target in the analyte. Localized field gradients, generated by currents flowing through micrometer sized metallic conductors integrated with MR sensors have been shown to reduce the hybridization time of complementary target DNA with probe DNA molecules immobilized on the sensor to several minutes compared with many hours for standard diffusion limited DNA-chip assays [6].