Robust and easy-to-use kits specific for a particular DNA sequence are desirable for early detection of diseases. However, the major challenge with these tests is often the background fluorescence artifacts arising fr...Robust and easy-to-use kits specific for a particular DNA sequence are desirable for early detection of diseases. However, the major challenge with these tests is often the background fluorescence artifacts arising from biological species due to employing UV and visible range of light. Here, we have reported a near-infrared (NIR) fluorescence "turn-on" kit based on rare earth ions doped nanoparticles, upconversion nanoparticles (UCNPs), and gold nanoparticles (AuNPs), which forms a fluorescence-quencher pair,brought together by a hairpin structure through the formation of double-stranded DNA (dsDNA), with quenched upconversion luminescence. In the presence of analytes, the molecular beacon opens to push AuNPs away from UCNPs, with a distance longer than the efficient quenching distance, so that the inhibited upconversion emission will be restored. We demonstrated that this assay provides a homogeneous, facile, simple and highly selective HIV-1 based DNA detection system with restore efficiency up to 85%, and the detection limit of 5 nm.展开更多
β-NaYF4:Yb,Er nanoparticles (NPs) are one of the most efficient upconversion materials, which can convert near-infrared light to higher-energy light through multiple photon absorptions or energy transfer. In addition...β-NaYF4:Yb,Er nanoparticles (NPs) are one of the most efficient upconversion materials, which can convert near-infrared light to higher-energy light through multiple photon absorptions or energy transfer. In addition, they may be attractive alternative donors for luminescence resonance energy transfer (LRET) studies, because of their sharp absorption and emission profiles, high quantum yields, large anti-stokes shifts, long lifetime, low toxicity, and superior photo-stability. In principle, many problems of fluorescence resonance energy transfer (FRET), such as excitation of acceptors, emission overlaps between donors and acceptors, high background noise, potential toxicity, and instability, can be overcome using β-NaYF4:Yb,Er NPs as energy donors. Because the organic coating induced separation can significantly reduce the energy transfer efficiency and aqueous FRET system is difficult to be applied in devices, we demonstrate a novel NP-dye LRET system in solid state. The emission of the β-NaYF4:Yb,Er NPs at 539 nm overlaps with the absorption of the tetrametrylrhodarnine isothiocyante (TRITC), satisfying the requirement of LRET process. Since TRITC molecules are adsorbed on the β-NaYF4:Yb,Er NPs by an electrostatic interaction, the interaction distance is suitable for LRET without any further modulation. The resultant solid LRET system is ready for the further applications for devices.展开更多
In this paper,we designed Eu^(2+)-doped BaAlF_(5) and BaSiF_(6) downconversion nanophosphors with strong f-f transition emission to realize the quantitative detection of TNP.The surface of the as-prepared nanophosphor...In this paper,we designed Eu^(2+)-doped BaAlF_(5) and BaSiF_(6) downconversion nanophosphors with strong f-f transition emission to realize the quantitative detection of TNP.The surface of the as-prepared nanophosphors was modified by polyethylenimine(PEI) to increase the water solubility and to provide a pair of electrons to bind to the benzene ring in TNP,forming a Meisenheimer complex.The detection principle of TNP is based on luminescence resonance energy transfer(LRET) technology,where the PEI-functionalized BaAlF_(5):Eu^(2+) and BaSiF_(6):Eu^(2+) nanophosphors are used as energy donors and TNP is an energy acceptor.With increasing TNP concentrations,the luminescence intensity of the BaAlF5:Eu^(2+) and BaSiF6:Eu^(2+) nanophosphors at 359 nm [^(4)f_(7)(^(6)P_(7/2))→^(4)f_(7)(^(8)S_(7/2)) transition of Eu^(2+)] displays dramatic luminescent quenching.The BaAlF_(5):Eu^(2+)@PEI or BaSiF_(6):Eu^(2+)@PEI nanophosphor downconversion luminescent sensors show great sensitivity and selectivity and good linearity,and the detection limits of TNP are 0.57 and 2.82 ng/mL,respectively.展开更多
基金supported by the Australian Research Council(ARC)Future Fellowship Scheme(D.J.,FT130100517)ARC Industry Transformational Research Hub Scheme(IH150100028)
文摘Robust and easy-to-use kits specific for a particular DNA sequence are desirable for early detection of diseases. However, the major challenge with these tests is often the background fluorescence artifacts arising from biological species due to employing UV and visible range of light. Here, we have reported a near-infrared (NIR) fluorescence "turn-on" kit based on rare earth ions doped nanoparticles, upconversion nanoparticles (UCNPs), and gold nanoparticles (AuNPs), which forms a fluorescence-quencher pair,brought together by a hairpin structure through the formation of double-stranded DNA (dsDNA), with quenched upconversion luminescence. In the presence of analytes, the molecular beacon opens to push AuNPs away from UCNPs, with a distance longer than the efficient quenching distance, so that the inhibited upconversion emission will be restored. We demonstrated that this assay provides a homogeneous, facile, simple and highly selective HIV-1 based DNA detection system with restore efficiency up to 85%, and the detection limit of 5 nm.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20821091 and 20671005)the National Natural Science Foundation of China & Research Grants Council (20731160001)the Ministry of Science and Technology of China (Grant No. 2006CB601104)
文摘β-NaYF4:Yb,Er nanoparticles (NPs) are one of the most efficient upconversion materials, which can convert near-infrared light to higher-energy light through multiple photon absorptions or energy transfer. In addition, they may be attractive alternative donors for luminescence resonance energy transfer (LRET) studies, because of their sharp absorption and emission profiles, high quantum yields, large anti-stokes shifts, long lifetime, low toxicity, and superior photo-stability. In principle, many problems of fluorescence resonance energy transfer (FRET), such as excitation of acceptors, emission overlaps between donors and acceptors, high background noise, potential toxicity, and instability, can be overcome using β-NaYF4:Yb,Er NPs as energy donors. Because the organic coating induced separation can significantly reduce the energy transfer efficiency and aqueous FRET system is difficult to be applied in devices, we demonstrate a novel NP-dye LRET system in solid state. The emission of the β-NaYF4:Yb,Er NPs at 539 nm overlaps with the absorption of the tetrametrylrhodarnine isothiocyante (TRITC), satisfying the requirement of LRET process. Since TRITC molecules are adsorbed on the β-NaYF4:Yb,Er NPs by an electrostatic interaction, the interaction distance is suitable for LRET without any further modulation. The resultant solid LRET system is ready for the further applications for devices.
基金the National Natural Science Foundation of China(21173034)the Fundamental Research Funds for the Central Universities of China(wd01206)。
文摘In this paper,we designed Eu^(2+)-doped BaAlF_(5) and BaSiF_(6) downconversion nanophosphors with strong f-f transition emission to realize the quantitative detection of TNP.The surface of the as-prepared nanophosphors was modified by polyethylenimine(PEI) to increase the water solubility and to provide a pair of electrons to bind to the benzene ring in TNP,forming a Meisenheimer complex.The detection principle of TNP is based on luminescence resonance energy transfer(LRET) technology,where the PEI-functionalized BaAlF_(5):Eu^(2+) and BaSiF_(6):Eu^(2+) nanophosphors are used as energy donors and TNP is an energy acceptor.With increasing TNP concentrations,the luminescence intensity of the BaAlF5:Eu^(2+) and BaSiF6:Eu^(2+) nanophosphors at 359 nm [^(4)f_(7)(^(6)P_(7/2))→^(4)f_(7)(^(8)S_(7/2)) transition of Eu^(2+)] displays dramatic luminescent quenching.The BaAlF_(5):Eu^(2+)@PEI or BaSiF_(6):Eu^(2+)@PEI nanophosphor downconversion luminescent sensors show great sensitivity and selectivity and good linearity,and the detection limits of TNP are 0.57 and 2.82 ng/mL,respectively.
