Design and fabrication of bio-magnetic sensors and magnetic nanobead labels for DNA detection and identification

In this paper, the main challenges in developing a magnetic DNA microarray include: 1) The spin valve sensors must be sensitive to as few as 1-10 nanobeads to be useful for applications such as biological pathogen detection; to achieve this, the distance between the sensor and magnetic labels must be minimized. 2) The nanobeads must be monodisperse, water soluble, chemically and magnetically stable, and functionalized to attach to a DNA fragment; the nanobeads should also be superparamagnetic so that they will not agglomerate in the absence of applied fields. 3) The bio-magnetic DNA microarrays need to be designed to maximise the active sensing surface area.