title: DNA-templated Ag nanoclusters as fluorescent probes for sensing and intracellular imaging of hydroxyl radicals.
abstract: We have developed a simple, rapid and label-free sensor for the essential biological OH radicals based on the fluorescence quenching of DNA-templated Ag nanoclusters (DNA-Ag NCs). The OH radicals generated from the Fenton reagent attack and cleave the DNA template, which disturbs the microenvironments around Ag NCs, resulting in spontaneous aggregation due to the lack of stabilization and further the quenching of the Ag NCs fluorescence. These changes in fluorescence intensity allow sensing of OH radicals with good sensitivity and selectivity under optimal conditions. The sensor can be also applied for quantifying the radical scavenging action of antioxidants. Various characterizations including absorption spectra, fluorescence lifetimes, light scattering (LS) spectra, transmission electron microscopy (TEM), dark field light scattering imaging, and circular dichroism (CD) spectrometry have been employed to illustrate the proposed sensing mechanism. Further investigations demonstrate that the fluorescent probe could penetrate into intact cell membranes to selectively detect intracellular OH radicals induced by the phorbol myristate acetate (PMA) stimulation. These advantageous characteristics make the fluorescent DNA-Ag NCs potentially useful as a new candidate to monitor OH in broad biosystems.
authors.affiliation: Department of Chemistry, Nanchang University, Nanchang 330031, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Ru-Ping
authors.initials: RP
authors.lastname: Liang
authors.forename: Sai-Jin
authors.initials: SJ
authors.lastname: Xiao
authors.forename: Jian-Mei
authors.initials: JM
authors.lastname: Bai
authors.forename: Lin-Ling
authors.initials: LL
authors.lastname: Zheng
authors.forename: Lei
authors.initials: L
authors.lastname: Zhan
authors.forename: Xi-Juan
authors.initials: XJ
authors.lastname: Zhao
authors.forename: Jian-Ding
authors.initials: JD
authors.lastname: Qiu
authors.forename: Cheng-Zhi
authors.initials: CZ
authors.lastname: Huang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D005456:Fluorescent Dyes; D006801:Humans; D006861:Hydrogen Peroxide; D017665:Hydroxyl Radical / Q000737:chemistry*; D007501:Iron; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology*; D012834:Silver / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D014407:Tumor Cells, Cultured
chemical_list: C045076:Fenton's reagent; D005456:Fluorescent Dyes; D017665:Hydroxyl Radical; D012834:Silver; D004247:DNA; D006861:Hydrogen Peroxide; D007501:Iron
keywords: Ag nanoclusters; Fluorescent probe; Hydroxyl radicals; Intracellular imaging