TABLE 5.

Examples of potentiometric and amperometric electrochemical biosensors for detection of whole bacterial cells^a

Biosensor type	Bacterium	Transducer	Technique	Bioreceptor	LOD	Comment	Reference
Potentiometric	Sulfate-reducing bacteria	Glassy carbon electrode	Potentiometric stripping analysis	None	2.3 × 10–2.3 × 107 CFU/ml	Need bacterial processing	74
	Staphylococcus aureus	Single-walled carbon nanotubes	EMF	Aptamer	8 × 102 CFU/ml	Bacterium-spiked pig skin	75
Amperometric	E. coli	Photolithographic gold	Immunomagnetic/amperometric in flow cells	Antibody	55 cells/ml in PBS, 100 cells/ml in milk	No contact of biocomponent with sensor	76
	E. coli K-12	Screen-printed carbon electrodes	Phage-induced release and subsequent quantitation of bacterial intracellular enzyme	Bacteriophage	1 CFU/100 ml	Cells not intact after analysis	77
	Heat-killed E. coli	SCE	Amperometric detection of secondary antibody with GOD	Biotinyl antibody	3 × 101–3.2 × 106 CFU/ml, down to 15 CFU/ml	Labeling needed but tested in synthetic stool	78
	Staphylococcus aureus	DropSens screen-printed gold electrodes	HRP H2O2-mediated immunosensor	Antibody	1 CFU/ml of raw milk	Indirect, label needed	79

^aAbbreviations: SCE, saturated calomel electrode; GOD, glucose oxidase; EMF, electron motive force; HRP, horseradish peroxidase.