title: An organophosphate sensor based on photo-crosslinked hydrogel-entrapped E. coli.
abstract: This paper describes a whole cell sensor using E. coli entrapped within photocrosslinked hydrogel beads. Hydrogel beads containing organophosphorus hydrolase (OPH)-expressed E. coli were prepared by adding a hydrogel precursor solution containing the E. coli to an oil phase using a precision syringe pump, forming droplets, and photopolymerizing them. The beads showed good monodispersity with an average size of 1.2 mm. We detected organophosphates (OPs) using the beads. The detection relied on a pH-sensitive fluorescence dye that responds to protons produced from the intracellular OPH reaction with the OPs. This sensor could detect up to 80 μM of paraoxon with a detection limit of 3 μM. The enzyme activity of E. coli entrapped within the hydrogel beads showed stable enzyme activity for at least two weeks. This whole cell sensor will be implemented in a microfluidic system by directly photopolymerizing the hydrogel precursor solution within microfluidic channels.
authors.affiliation: Department of Chemistry, University of Rochester.
authors.forename: Valerie
authors.initials: V
authors.lastname: Fleischauer
authors.forename: Jinseok
authors.initials: J
authors.lastname: Heo
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005452:Fluoresceins / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D005818:Genetic Engineering; D020100:Hydrogels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D044085:Microfluidics; D010755:Organophosphates / Q000032:analysis*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D003432:Cross-Linking Reagents; D005452:Fluoresceins; D005456:Fluorescent Dyes; D020100:Hydrogels; D010755:Organophosphates; C401959:seminaphthofluorescein; C045290:phosphorylphosphatase; D010744:Phosphoric Monoester Hydrolases