title: Nano-conjugate fluorescence probe for the discrimination of phosphate and pyrophosphate.
abstract: We describe a pyrophosphate (PPi) probe that is based on a fluorescent dicarboxylate-substituted poly(para-phenyleneethynylene) (PPE) and 10 nm cobalt-iron spinel nanoparticles (NPs) in aqueous media. The spinel NPs efficiently quench the fluorescence of the PPE at a concentration of 20-30 pmol. Addition of phosphate anions to the PPE-NP construct displaces the quenched PPE to give rise to a fluorescent response; we found that PPi and phosphate (Pi) have significantly different binding affinities for the self-assembled materials. We can discern >40 nM PPi in the presence of 0.1 mM Pi at pH 7, which suggests that these assemblies may be useful in bio-analytical applications. This displacement assay was used to effectively determine the ability of pyrophosphatase to hydrolyze PPi to Pi.
authors.affiliation: School of Chemistry and Biochemistry, 901 Atlantic Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Ik-Bum
authors.initials: IB
authors.lastname: Kim
authors.forename: Man H
authors.initials: MH
authors.lastname: Han
authors.forename: Ronnie L
authors.initials: RL
authors.lastname: Phillips
authors.forename: Bappaditya
authors.initials: B
authors.lastname: Samanta
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Rotello
authors.forename: Z John
authors.initials: ZJ
authors.lastname: Zhang
authors.forename: Uwe H F
authors.initials: UH
authors.lastname: Bunz
mesh_terms: D000480:Alkynes / Q000737:chemistry; D000537:Aluminum Oxide / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry; D011756:Diphosphates / Q000032:analysis*; D004573:Electrolytes / Q000737:chemistry; D004987:Ethers / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D007700:Kinetics; D008277:Magnesium Oxide / Q000737:chemistry; D008280:Magnetics; D008958:Models, Molecular; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry*; D010710:Phosphates / Q000032:analysis*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D055672:Static Electricity; D014867:Water / Q000737:chemistry
chemical_list: D000480:Alkynes; D011756:Diphosphates; D004573:Electrolytes; D004987:Ethers; D005290:Ferric Compounds; D005456:Fluorescent Dyes; D010710:Phosphates; C436384:phenyleneethynylene; C111130:spinell; D014867:Water; C001215:ferrite; D008277:Magnesium Oxide; D003035:Cobalt; D000537:Aluminum Oxide