title: Mass effect of redox reactions: A novel mode for surface plasmon resonance-based bioanalysis.
abstract: The pursuit of more specific and sensitive response is a perpetual goal for modern bioassays. This work proposed a novel label-free strategy about redox-related mass effect based on the surface plasmon resonance (SPR) technique for ultrasensitive determination of DNA. The protocol starts with the modification of SPR gilded disk with the capture DNA (cDNA). After the conjugation of immobilized cDNA with the target DNA (tDNA), the hybridization chain reaction was triggered by the introduction of mutual partial complementary primers to elongate the terminal into a nanoscale duplex. As it is reported that porphyrin could intercalate into the grooves of the double-stranded DNA (dsDNA) scaffold, multiple positive-charged Fe(III)meso-tetra(N-methyl-4-pyridyl) porphine (FeTMPyP) with symmetric structure were uptaken for in situ formation of porphyrin-dsDNA complex. Given FeTMPyP a highly efficient catalysis for the peroxide reduction, its presence as a biomimetic cofactor was validated via circular dichroism and UV-vis spectroscopy, demonstrating a tight binding as well as high catalytic activity and stability. Using 4-chloro-1-naphthol as a proton donor, the catalytic reduction of H2O2 would oxidize it into insoluble benzo-4-chloro-hexadienone, which simultaneously deposited on the heterogeneous interface, leading to a significant amplification in both SPR response and topological height profile. The signal increment was proportional to the concentration of tDNA, thus an ultrasensitive SPR-based DNA assay was developed with a linear range over four orders of magnitudes and a sub-femtomolar detection limit of 0.73 fM. The developed methodology exemplifies a different way of thinking about mass-sensing modes, extending conventional SPR-based DNA analysis to relevant biomedical applications.
authors.affiliation: Sino-French Laboratory of Biomaterials and Bioanalytical Chemistry, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
authors.forename: Pei-Xin
authors.initials: PX
authors.lastname: Yuan
authors.affiliation: Sino-French Laboratory of Biomaterials and Bioanalytical Chemistry, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China. Electronic address: sydeng@njust.edu.cn.
authors.forename: Sheng-Yuan
authors.initials: SY
authors.lastname: Deng
authors.affiliation: Sino-French Laboratory of Biomaterials and Bioanalytical Chemistry, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Xin
authors.affiliation: Sino-French Laboratory of Biomaterials and Bioanalytical Chemistry, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
authors.forename: Xu-Bo
authors.initials: XB
authors.lastname: Ji
authors.affiliation: Sino-French Laboratory of Biomaterials and Bioanalytical Chemistry, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China. Electronic address: danshan@njust.edu.cn.
authors.forename: Dan
authors.initials: D
authors.lastname: Shan
authors.affiliation: University of Grenoble, Alpes-CNRS, DCM UMR 5250, F-38000 Grenoble, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Cosnier
mesh_terms: D004247:DNA / Q000032:analysis*; D006861:Hydrogen Peroxide / Q000737:chemistry; D061925:Immobilized Nucleic Acids / Q000737:chemistry; D057230:Limit of Detection; D008958:Models, Molecular; D009284:Naphthols / Q000737:chemistry; D009693:Nucleic Acid Hybridization; D010084:Oxidation-Reduction; D011166:Porphyrins / Q000737:chemistry; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D061925:Immobilized Nucleic Acids; D009284:Naphthols; D011166:Porphyrins; C025917:4-chloro-1-naphthol; C107018:porphine; D004247:DNA; D006861:Hydrogen Peroxide
keywords: DNA assay; Hybridization chain reaction; Iron porphyrin; Reaction-concomitant mass effect; Surface plasmon resonance