Detection of target ssDNA using a microfabricated hall magnetometer with correlated optical readout

Abstract

Sensing biological agents at the genomic level, while enhancing the response time for biodetection over commonly used, optics-based techniques such as nucleic acid microarrays or enzyme-linked immunosorbent assays (ELISAs), is an important criterion for new biosensors. Here, we describe the successful detection of a 35-base, single-strand nucleic acid target by Hall-based magnetic transduction as a mimic for pathogenic DNA target detection. The detection platform has low background, large signal amplification following target binding and can discriminate a single, 350nm superparamagnetic bead labeled with DNA. Detection of the target sequence was demonstrated at 364pM (2 target DNA strands per bead) target DNA in the presence of 36M nontarget (noncomplementary) DNA (10ppm target DNA) using optical microscopy detection on a GaAs Hall mimic. The use of Hall magnetometers as magnetic transduction biosensors holds promise for multiplexing applications that can greatly improve point-of-care (POC) diagnostics and subsequent medical care. Copyright 2012 Steven M. Hira et al.