Abstract: This invention presents rapid methods for evaluating the effects of antimicrobial compounds on microorganisms based upon the microorganism's ability to transport electrons to an external chemical oxidant (a mediator) that is added to the microorganism sample. The mediator interacts with the terminal components of the respiratory pathway and the extent of its consumption is related to the ability of the microorganism to respire. However, under the assay conditions described herein the extent of mediator consumption is different from the microorganisms' ability to consume oxygen, due to the addition of metabolizable compounds to the assay mixtures. The consumed mediator is subsequently measured electrochemically (amperometrically or coulometrically) at the working electrode of a standard two-electrode or three-electrode electrochemical cell.

Abstract: The present invention relates to a voltammetric sequence-selective sensor for target polynucleotide sequences which essentially comprises: an immobilized polynucleotide probe having one end covalently bound onto an amperometric electrode. The immobilized probe includes a target binding region capable of hybridizing to the target polynucleotide sequences forming an immobilized heteroduplex having at least a hybridized region. The sequence-selective sensor of the present invention also comprises means for voltammetrically detecting immobilized heteroduplexes. There is also provided a method for detecting the presence of a target polynucleotide analyte in a physiological sample, which comprises the steps of incubating the prepared physiological sample with the voltammetric sequence-selective sensor of the present invention; voltammetrically detecting immobilized heteroduplexes; and comparing the resulting voltammogram with a control voltammogram.