Matrix independent label-free nanoelectronic biosensor

Previously we presented a novel, label free and real time electrical impedance biosensor, referred to as the nanoneedle biosensor. The nanoneedle is an ultrasensitive and localized device, which has the ability to directly measure biomolecular binding as a function of time. Label-free electronic sensors generally operate in low salt-concentration buffers [1] making them impractical for analyzing complex biological mixtures, which have salt concentrations as high as several hundred millimolar. In this study we have demonstrated detection of a clinically relevant cancer biomarker suspended in high salt buffer (> 100mM) with a detection limit of 2 ng/ml.