Use of magnetoresistive biochips for monitoring of pathogenic microorganisms in water through bioprobes: Oligonucleotides and antibodies

Abstract

Magnetoresistive spin valve sensors have been integrated in a micro-engineered biochip and applied to the detection of pathogenic microorganisms for water biological quality management. Two different strategies of biomolecular recognition events, involving 16S rDNA oligonucleotide sequences and antibodies as recognition agents, are suggested for the detection of Escherichia coli and Salmonella sp. as model microorganisms. The development of the platform involves the immobilization of specific probes for target capture, as well as the labeling of the target species with nanometer-sized paramagnetic markers. The molecular interaction between probe and target is monitored almost in real-time through the measurement of the variation of the sensor resistance with the magnetic stray fields created by the labels. Preliminary results for the detection of Salmonella whole cells using this immunosensor platform are presented.