title: Colorimetric bacteria sensing using a supramolecular enzyme-nanoparticle biosensor.
abstract: Rapid and sensitive detection of pathogens is a key requirement for both environmental and clinical settings. We report here a colorimetric enzyme-nanoparticle conjugate system for detection of microbial contamination. In this approach, cationic gold nanoparticles (NPs) featuring quaternary amine headgroups are electrostatically bound to an enzyme [β-galactosidase (β-Gal)], inhibiting enzyme activity. Analyte bacteria bind to the NP, which releases the β-Gal and restores its activity, providing an enzyme-amplified colorimetric readout of the binding event. Using this strategy, we have been able to quantify bacteria at concentrations of 1 × 10(2) bacteria/mL in solution and 1 × 10(4) bacteria/mL in a field-friendly test strip format.
authors.affiliation: Department of Chemistry, University of Massachusetts, 710 North Pleasant Street, Amherst, Massachusetts 01003, USA.
authors.forename: Oscar R
authors.initials: OR
authors.lastname: Miranda
authors.forename: Xiaoning
authors.initials: X
authors.lastname: Li
authors.forename: Limary
authors.initials: L
authors.lastname: Garcia-Gonzalez
authors.forename: Zheng-Jiang
authors.initials: ZJ
authors.lastname: Zhu
authors.forename: Bo
authors.initials: B
authors.lastname: Yan
authors.forename: Uwe H F
authors.initials: UH
authors.lastname: Bunz
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Rotello
mesh_terms: D001419:Bacteria / Q000302:isolation & purification*; D058491:Bacterial Load / Q000295:instrumentation / Q000379:methods*; D015374:Biosensing Techniques / Q000379:methods*; D003124:Colorimetry / Q000379:methods*; D006046:Gold; D053768:Metal Nanoparticles; D053758:Nanoparticles; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D006046:Gold; D001616:beta-Galactosidase