title: Peroxidase mimicking DNA-gold nanoparticles for fluorescence detection of the lead ions in blood.
abstract: Oligonucleotide (T30695) modified gold nanoparticles (T30695-Au NPs) have been prepared and employed for quantification of lead ions (Pb(2+)) in blood. The detection of Pb(2+) ions is through the formation of Au-Pb alloys and oligonucleotide-Pb(2+) complexes that catalyze the H(2)O(2)-mediated oxidation of non-fluorescent Amplex UltraRed (AUR) to form a highly fluorescent oxidized AUR product. Surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS) and inductively coupled plasma mass spectrometry (ICP-MS) revealed the formation of Au-Pb alloys on the surfaces of the 40T30695-Au NPs (i.e., the system featuring 40 molecules of T30695 per Au NP) in the presence of Pb(2+) ions, leading to increased catalytic activity for the H(2)O(2)-mediated oxidation of AUR. The fluorescence intensity (excitation/emission maxima: ca. 540/584 nm) of the oxidized AUR product is proportional to the concentration of Pb(2+) ions over the range 0.1-100 nM, with a linear correlation (R(2) = 0.99). The 40T30695-Au NP/AUR probe is highly selective toward Pb(2+) ions (by at least 200-fold over other tested metal ions). The 40T30695-Au NPs/AUR probe provided limits of detection (LOD, at a signal-to-noise ratio 3) for Pb(2+) ions of 0.05 and 0.1 nM, in Tris-acetate solution (5 mM, pH 8.0) without and with salt (150 mM NaCl, 5 mM KCl, 1 mM MgCl(2), and 1 mM CaCl(2)), respectively. Without conducting tedious sample pretreatment, the approach allows detection of Pb(2+) ions in blood samples, showing the potential of the 40T30695-Au NPs/AUR assay for on-site and real-time detection of Pb(2+) ions in biological samples.
authors.affiliation: Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei, 10617, Taiwan.
authors.forename: Chi-Lin
authors.initials: CL
authors.lastname: Li
authors.forename: Chih-Ching
authors.initials: CC
authors.lastname: Huang
authors.forename: Wei-Hsi
authors.initials: WH
authors.lastname: Chen
authors.forename: Cheng-Kang
authors.initials: CK
authors.lastname: Chiang
authors.forename: Huan-Tsung
authors.initials: HT
authors.lastname: Chang
mesh_terms: D015374:Biosensing Techniques; D006046:Gold / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D007854:Lead / Q000097:blood*; D053768:Metal Nanoparticles / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry*; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000737:chemistry / Q000378:metabolism*; D059629:Signal-To-Noise Ratio; D013050:Spectrometry, Fluorescence
chemical_list: D007477:Ions; D009841:Oligonucleotides; D007854:Lead; D006046:Gold; D006861:Hydrogen Peroxide; D009195:Peroxidase