title: Magnetite nanoparticle-induced fluorescence quenching of adenosine triphosphate-BODIPY Conjugates: application to adenosine triphosphate and pyrophosphate sensing.
abstract: We report that magnetite nanoparticles (Fe3O4 NPs) act as an efficient quencher for boron dipyrromethene-conjugated adenosine 5'-triphosphate (BODIPY-ATP) that is highly fluorescent in bulk solution. BODIPY-ATP molecules attached to the surface of Fe3O4 NPs through the coordination between the triphosphate group of BODIPY-ATP and Fe(3+)/Fe(2+) on the NP surface. The formed complexes induced an apparent reduction in the BODIPY-ATP fluorescence resulting from an oxidative-photoinduced electron transfer (PET) from the BODIPY-ATP excited state to an unfilled d shell of Fe(3+)/Fe(2+) on the NP surface. A comparison of the Stern-Volmer quenching constant between Fe(3+) and Fe(2+) suggests that Fe(3+) on the NP surface dominantly controls this quenching process. The efficiency for Fe3O4 NP-induced fluorescence quenching of the BODIPY-ATP was enhanced by increasing the concentration of Fe3O4 NPs and lowering the pH of the solution to below 6.0. We found that pyrophosphate and ATP compete with BODIPY-ATP for binding to Fe3O4 NPs. Thus, we amplified BODIPY-ATP fluorescence in the presence of increasing the pyrophosphate and ATP concentration; the detection limits at a signal-to-noise ratio of 3 for pyrophosphate and ATP were determined to be 7 and 30 nM, respectively. The Fe3O4 NP-based competitive binding assay detected ATP and pyrophosphate in only 5 min. The selectivity of this assay for ATP over metal ions, amino acids, and adenosine analogues is particularly high. The practicality of using the developed method to determine ATP in a single drop of blood is also validated.
authors.affiliation: Department of Chemistry, National Sun Yat-sen University , Taiwan.
authors.forename: Cheng-Ju
authors.initials: CJ
authors.lastname: Yu
authors.forename: Su-Mei
authors.initials: SM
authors.lastname: Wu
authors.forename: Wei-Lung
authors.initials: WL
authors.lastname: Tseng
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis* / Q000097:blood; D015374:Biosensing Techniques / Q000379:methods*; D001896:Boron Compounds / Q000737:chemistry*; D011756:Diphosphates / Q000032:analysis*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D011756:Diphosphates; D005456:Fluorescent Dyes; D058185:Magnetite Nanoparticles; C107241:diphosphoric acid; D000255:Adenosine Triphosphate