Magnetic microtags and magnetic encoding for applications in biotechnology

Abstract

Microarrays and suspension-based technologies have attracted significant interest recently due to their broad range of applications in medical diagnostics and high throughput molecular biology. The throughput of microarrays is limited by the array density. On the contrary, suspension-based technologies offer a conceptually different approach due to their ability to extend the detection capability by expanding the size of a chemical library (probes). To date, suspension-based methods are limited by the number of distinct codes the solid supports can carry. Here, we present a novel encoding method based on magnetic tags that can be remotely encoded and decoded as they flow in microfluidic channels, by means of magnetic read/write heads. The microtags consist of a substrate and ferromagnetic elements that are individually addressable by the external sensor and can be functionalized with various biochemical probe compounds. We present experimental data demonstrating the reading of individual elements from samples comprising 50×20µm 2 Ni microbars. The samples are prepared by electrodeposition and read by a micro-fluxgate magnetic sensor set-up for vertical field detection. © 2008 American Institute of Physics.