title: Photoinduced electron transfer between Fe(III) and adenosine triphosphate-BODIPY conjugates: Application to alkaline-phosphatase-linked immunoassay.
abstract: Fluorescent boron dipyrromethene (BODIPY) analogs are often used as sensors for detecting various species because of their relatively high extinction coefficients, outstanding fluorescence quantum yields, photostability, and pH-independent fluorescence. However, there is little-to-no information in the literature that describes the use of BODIPY analogs for detecting alkaline phosphatase (ALP) activity and inhibition. This study discovered that the fluorescence of BODIPY-conjugated adenosine triphosphate (BODIPY-ATP) was quenched by Fe(III) ions through photoinduced electron transfer. The ALP-catalyzed hydrolysis of BODIPY-ATP resulted in the formation of BODIPY-adenosine and phosphate ions. The fluorescence of the generated BODIPY-adenosine was insensitive to the change in the concentration of Fe(III) ions. Thus, the Fe(III)-induced fluorescence quenching of BODIPY-ATP can be paired with its ALP-mediated dephosphorylation to design a turn-on fluorescence probe for ALP sensing. A method detection limit at a signal-to-noise ratio of 3 for ALP was estimated to be 0.02 units/L (~6 pM; 1 ng/mL). This probe was used for the screening of ALP inhibitors, including Na3VO4, imidazole, and arginine. Because ALP is widely used in enzyme-linked immunosorbent assays, the probe was coupled to an ALP-linked immunosorbent assay for the sensitive and selective detection of immunoglobulin G (IgG). The lowest detectable concentration for IgG in this system was 5 ng/mL. Compared with the use of 3,6-fluorescein diphosphate as a signal reporter in an ALP-linked immunosorbent assay, the proposed system provided comparable sensitivity, large linear range, and high stability over temperature and pH changes.
authors.affiliation: Department of Chemistry, National Sun Yat-sen University, Taiwan.
authors.forename: Jia-Hui
authors.initials: JH
authors.lastname: Lin
authors.affiliation: Department of Chemistry, National Sun Yat-sen University, Taiwan.
authors.forename: Ya-Chun
authors.initials: YC
authors.lastname: Yang
authors.affiliation: Department of Chemistry, National Sun Yat-sen University, Taiwan.
authors.forename: Ya-Chen
authors.initials: YC
authors.lastname: Shih
authors.affiliation: Department of Chemistry, National Sun Yat-sen University, Taiwan.
authors.forename: Szu-Ying
authors.initials: SY
authors.lastname: Hung
authors.affiliation: Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Chi-Yu
authors.initials: CY
authors.lastname: Lu
authors.affiliation: Department of Chemistry, National Sun Yat-sen University, Taiwan; School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Taiwan; Center for Nanoscience and Nanotechnology, National Sun Yat-sen University, Taiwan. Electronic address: tsengwl@mail.nsysu.edu.tw.
authors.forename: Wei-Lung
authors.initials: WL
authors.lastname: Tseng
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry* / Q000528:radiation effects; D000469:Alkaline Phosphatase / Q000032:analysis* / Q000737:chemistry*; D001896:Boron Compounds / Q000737:chemistry* / Q000528:radiation effects; D004579:Electron Transport / Q000528:radiation effects; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007501:Iron / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D058726:Nanoconjugates / Q000737:chemistry / Q000528:radiation effects
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D058726:Nanoconjugates; D000255:Adenosine Triphosphate; D007501:Iron; D000469:Alkaline Phosphatase
keywords: Alkaline phosphatase; Fluorescent sensor; Immunoassay