Giant Magnetoresistive Biochips for Genetic and Protein Assays

Giant magnetoresistive (GMR) biochips based on spin valve (SV) sensor arrays and magnetic nanoparticle labels (nanotags) have been successfully applied to the detection of biological events in the form of both protein and DNA assays with great speed, sensitivity, selectivity, and economy. The most tangible and unique feature of the GMR biochip in our work is that it uses magnetic nanoparticles (also called nanotags) with a mean diameter of only approximately 100-500 Aring as the tags. We have prototyped biochips with an 8 x 8 array of 64 giant magnetoresistance (GMR) spin valve sensors, each of which consists of 32 giant magnetoresistance (GMR) strips which are 1.5 mum wide by 110 mum long and in series connection. We have also successfully shown our magneto-nano chip can be used for 4-plex human papillomavirus (HPV) genotyping. The results suggest that magneto-nano biochip holds great promises in biomedicine, particularly for point of care molecular diagnostics of cancer, infectious diseases, radiation injury, cardiac diseases, and other diseases.