title: Distance-dependent metal-enhanced quantum dots fluorescence analysis in solution by capillary electrophoresis and its application to DNA detection.
abstract: Here the distance dependence of metal-enhanced quantum dots (QDs) fluorescence in solution is studied systematically by capillary electrophoresis (CE). Complementary DNA oligonucleotides-modified CdSe/ZnS QDs and gold nanoparticles (Au NPs) were connected together in solution by the hybridization of complementary oligonucleotides, and a model system (QD-Au) for the study of metal-enhanced QDs fluorescence was constructed, in which the distance between the QDs and Au NPs was controlled by adjusting the base number of the oligonucleotide. In our CE experiments, the metal-enhanced fluorescence of the QDs solution was only observed when the distance between the QDs and Au NPs ranged from 6.8 to 18.7 nm, and the maximum enhancement by a factor of 2.3 was achieved at 11.9 nm. Furthermore, a minimum of 19.6 pg of target DNA was identified in CE based on its specific competition with the QD-DNA in the QD-Au system. This work provides an important reference for future study of metal-enhanced QDs fluorescence in solution and exhibits potential capability in nucleic acid hybridization analysis and high-sensitivity DNA detection.
authors.affiliation: Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
authors.forename: Yong-Qiang
authors.initials: YQ
authors.lastname: Li
authors.forename: Li-Yun
authors.initials: LY
authors.lastname: Guan
authors.forename: Hai-Li
authors.initials: HL
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Song
authors.initials: S
authors.lastname: Lin
authors.forename: Zhi-Ya
authors.initials: ZY
authors.lastname: Ma
authors.forename: Yuan-Di
authors.initials: YD
authors.lastname: Zhao
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry; D004247:DNA / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D008670:Metals / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry; D045663:Quantum Dots; D012996:Solutions / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D008670:Metals; D009841:Oligonucleotides; D012996:Solutions; D013440:Sulfides; D017967:Zinc Compounds; C034939:cadmium sulfide; D006046:Gold; D004247:DNA; C031238:zinc sulfide