title: Electrochemical nanoparticle-enzyme sensors for screening bacterial contamination in drinking water.
abstract: Traditional plating and culturing methods used to quantify bacteria commonly require hours to days from sampling to results. We present here a simple, sensitive and rapid electrochemical method for bacterial detection in drinking water based on gold nanoparticle-enzyme complexes. The gold nanoparticles were functionalized with positively charged quaternary amine headgroups that could bind to enzymes through electrostatic interactions, resulting in inhibition of enzymatic activity. In the presence of bacteria, the nanoparticles were released from the enzymes and preferentially bound to the bacteria, resulting in an increase in enzyme activity, releasing a redox-active phenol from the substrate. We employed this strategy for the electrochemical sensing of Escherichia coli and Staphylococcus aureus, resulting in a rapid detection (<1 h) with high sensitivity (10(2) CFU mL(-1)).
authors.affiliation: Department of Food Science, University of Massachusetts, 102 Holdsworth Way, Amherst, Massachusetts 01003, USA. snugen@foodsci.umass.edu.
authors.forename: Juhong
authors.initials: J
authors.lastname: Chen
authors.forename: Ziwen
authors.initials: Z
authors.lastname: Jiang
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Ackerman
authors.forename: Mahdieh
authors.initials: M
authors.lastname: Yazdani
authors.forename: Singyuk
authors.initials: S
authors.lastname: Hou
authors.forename: Sam R
authors.initials: SR
authors.lastname: Nugen
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Rotello
mesh_terms: D015374:Biosensing Techniques / Q000191:economics / Q000379:methods*; D060766:Drinking Water / Q000382:microbiology*; D055664:Electrochemical Techniques / Q000191:economics / Q000379:methods; D004800:Enzymes, Immobilized / Q000737:chemistry; D004926:Escherichia coli / Q000302:isolation & purification*; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D009598:Nitrophenylgalactosides / Q000737:chemistry; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D001616:beta-Galactosidase / Q000737:chemistry*
chemical_list: D060766:Drinking Water; D004800:Enzymes, Immobilized; C055012:2-nitrophenylgalactoside; D009598:Nitrophenylgalactosides; D006046:Gold; D001616:beta-Galactosidase