201
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Antelman J, Ebenstein Y, Dertinger T, Michalet X, Weiss S. Suppression of quantum dot blinking in DTT-doped polymer films. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2009; 113:11541-11545. [PMID: 20161096 PMCID: PMC2745152 DOI: 10.1021/jp811078e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this report we evaluate the emission properties of single quantum dots embedded in a thin, thiol containing polymer film. We report the suppression of quantum dot blinking leading to a continuous photon flux from both organic and water soluble quantum dots and demonstrate their application as robust fluorescent point sources for ultrahigh resolution localization. In addition, we apply the polymer coating to cell samples immunostained with antibody conjugated QDs and show that fluorescence intensity from the polymer embedded cells shows no sign of degradation after 67 hours of continuous excitation. The reported thin polymer film coating may prove advantageous for immuno-cyto/histo-chemistry as well as for the fabrication of quantum dot containing devices requiring a reliable and stable photon source (including a single photon source) or stable charge characteristics while maintaining intimate contact between the quantum dot and the surrounding matrix.
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Affiliation(s)
- Josh Antelman
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Yuval Ebenstein
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Thomas Dertinger
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Xavier Michalet
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Shimon Weiss
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095 USA
- Department of Physiology, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095 USA
- DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095 USA
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202
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Kim Y, Song NW, Yu H, Moon DW, Lim SJ, Kim W, Yoon HJ, Koo Shin S. Ligand-dependent blinking of zinc-blende CdSe/ZnS core/shell nanocrystals. Phys Chem Chem Phys 2009; 11:3497-502. [PMID: 19421553 DOI: 10.1039/b822351c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Blinking of zinc-blende CdSe/ZnS core/shell nanocrystals are studied as a function of surface passivating ligands. Organic-soluble CdSe/ZnS core/shell nanocrystals are prepared by colloidal synthesis free of trioctylphosphine oxide and converted into water-soluble ones by ligand exchange with three different hydrophilic thiols, 2-aminoethanethiol, 3-mercapto-1-propanol, and 3-mercaptopropionic acid. The zinc-blende lattice structure is confirmed by powder X-ray diffraction, the size and shape distributions are visualized by high-resolution transmission electron microscopy, and hydrodynamic size distributions of water-soluble nanocrystals are determined by dynamic light scattering. Ligand-dependent optical properties, such as the absorption and emission spectra as well as the photoluminescence lifetime, are obtained in both solution and glass substrate to characterize the effects of ligand on the bright state of nanocrystals. The time trace of blinking is recorded for single nanocrystals in polymer film. Both on- and off-time distributions are fit to a power law. The off-time exponents are clustered at 1.67+/-0.05, whereas the on-time exponents are scattered in the range of 1.71-2.25. The thiolate conjugation on the surface zinc atom greatly reduces the on-time duration, suggesting that the rate of photoinduced charge separation from the bright (on) to the dark (off) state increases as the number of surface hole-trap states increases.
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Affiliation(s)
- Yongwook Kim
- Bionanotechnology Center, Department of Chemistry, Pohang University of Science and Technology, San31 Hyoja-dong Nam-gu Pohang, Kyungbuk, 790-784, Korea
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203
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Hollingsworth JA, Vela J, Chen Y, Htoon H, Klimov VI, Casson AR. 'Giant' multishell CdSe nanocrystal quantum dots with suppressed blinking: Novel fluorescent probes for real-time detection of single-molecule events. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2009; 7189:718904. [PMID: 21804930 DOI: 10.1117/12.809678] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
We reported for the first time that key nanocrystal quantum dot (NQD) optical properties-quantum yield, photobleaching and blinking-can be rendered independent of NQD surface chemistry and environment by growth of a very thick, defect-free inorganic shell (Chen, et al. J. Am. Chem. Soc. 2008). Here, we show the precise shell-thickness dependence of these effects. We demonstrate that 'giant-shell' NQDs can be largely non-blinking for observation times as long as 54 minutes and that on-time fractions are independent of experimental time-resolution from 1-200 ms. These effects are primarily demonstrated on (CdSe)CdS (core)shell NQDs, but we also show that alloyed shells comprising Cd(x)Zn(1-x)S and terminated with a non-cytotoxic ZnS layer exhibit similar properties. The mechanism for suppressed blinking and dramatically enhanced stability is attributed to both effective isolation of the NQD core excitonic wavefunction from the NQD surface, as well as a quasi-Type II electronic structure. The unusual electronic structure provides for effective spatial separation of the electron and hole into the shell and core, respectively, and, thereby, for reduced efficiencies in non-radiative Auger recombination.
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204
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Sun L, Bao L, Hyun BR, Bartnik AC, Zhong YW, Reed JC, Pang DW, Abruña HD, Malliaras GG, Wise FW. Electrogenerated chemiluminescence from PbS quantum dots. NANO LETTERS 2009; 9:789-793. [PMID: 19115964 DOI: 10.1021/nl803459b] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report the first observation of electrogenerated chemiluminescence (ECL) from PbS quantum dots (QDs). Different ECL intensities are observed for different ligands used to passivate the QDs, which indicates that ECL is sensitive to surface chemistry, with the potential to serve as a powerful probe of surface states and charge transfer dynamics in QDs. In particular, passivation of the QD surfaces with trioctylphosphine (TOP) increases ECL intensity by 3 orders of magnitude when compared to passivation with oleic acid alone. The observed overlap of the ECL and photoluminescence spectra suggests a significant reduction of deep surface trap states from the QDs passivated with TOP.
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Affiliation(s)
- Liangfeng Sun
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.
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205
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Kulzer F, Laurens N, Besser J, Schmidt T, Orrit M, Spaink HP. Photothermal detection of individual gold nanoparticles: perspectives for high-throughput screening. Chemphyschem 2009; 9:1761-6. [PMID: 18666264 DOI: 10.1002/cphc.200800127] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We use photothermal microscopy to detect and image individual gold nanoparticles that are either embedded in a polymer film or immobilized in an aqueous environment. Reducing the numerical aperture of the detection optics allows us to achieve a 200-fold-enlarged detection volume while still retaining sufficient detectivity. We characterize the capabilities of this approach for the detection of gold colloids with a diameter of 20 nm, with emphasis on practical aspects that are important for high-throughput-screening applications. The extended detection volume in combination with the stability of the photothermal signal are major advantages compared to fluorescence-based approaches, which are limited by photoblinking and photobleaching. Careful consideration is given to the trade-off between the maximum increase in local temperature that can be tolerated by a biological specimen and the minimum integration time needed to reliably determine whether a given volume contains a target species. We find that our approach has the potential to increase the detection-limited flow rate (i.e. the limit given by the detection volume divided by the minimum detection time) by two to three orders of magnitude.
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Affiliation(s)
- Florian Kulzer
- Institute of Biology, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands
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206
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Chen H, Gai H, Yeung ES. Inhibition of photobleaching and blue shift in quantum dots. Chem Commun (Camb) 2009:1676-8. [DOI: 10.1039/b819356h] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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207
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Li M, Zaman MB, Bardelang D, Wu X, Wang D, Margeson JC, Leek DM, Ripmeester JA, Ratcliffe CI, Lin Q, Yang B, Yu K. Photoluminescent quantum dot–cucurbituril nanocomposites. Chem Commun (Camb) 2009:6807-9. [DOI: 10.1039/b913914a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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208
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Salehi A, Wu C, Zhan K, Mobley WC. Axonal Transport of Neurotrophic Signals: An Achilles' Heel for Neurodegeneration? INTRACELLULAR TRAFFIC AND NEURODEGENERATIVE DISORDERS 2009. [DOI: 10.1007/978-3-540-87941-1_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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209
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Wu C, Bull B, Szymanski C, Christensen K, McNeill J. Multicolor conjugated polymer dots for biological fluorescence imaging. ACS NANO 2008; 2:2415-23. [PMID: 19206410 PMCID: PMC2654197 DOI: 10.1021/nn800590n] [Citation(s) in RCA: 502] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Highly fluorescent conjugated polymer dots were developed for demanding applications such as fluorescence imaging in live cells. These nanoparticles exhibit small particle diameters, extraordinary fluorescence brightness, and excellent photostability. Single particle fluorescence imaging and kinetic studies indicate much higher emission rates (approximately 10(8) s(-1)) and little or no blinking of the nanoparticles as compared to typical results for single dye molecules and quantum dots. Analysis of single particle photobleaching trajectories reveals excellent photostabilityas many as 10(9) or more photons emitted per nanoparticle prior to irreversible photobleaching. The superior figures of merit of these new fluorescent probes, together with the demonstration of cellular imaging, indicate their enormous potential for demanding fluorescence-based imaging and sensing applications such as high speed super-resolution single molecule/particle tracking and highly sensitive assays.
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Affiliation(s)
- Changfeng Wu
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, USA
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210
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Fu Y, Zhang J, Lakowicz JR. Silver-enhanced fluorescence emission of single quantum dot nanocomposites. Chem Commun (Camb) 2008:313-5. [PMID: 19209313 DOI: 10.1039/b816736b] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel plasmon-coupled quantum dot (QD) nanocomposite via covalently interfacing the QD surfaces with silver nanoparticles was developed with greatly reduced blinking and enhanced emission fluorescence.
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Affiliation(s)
- Yi Fu
- Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, 725 W. Lombard Street, Baltimore, MD 21201, USA
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211
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Quantum dots for single-pair fluorescence resonance energy transfer in membrane- integrated EFoF1. Biochem Soc Trans 2008; 36:1017-21. [PMID: 18793181 DOI: 10.1042/bst0361017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
spFRET (single-pair fluorescence resonance energy transfer) with organic fluorophores has been used to demonstrate rotation of the subunits gamma and epsilon in membrane-integrated FoF1 during proton transport-coupled ATP synthesis. Owing to the high light intensities used in single-molecule spectroscopy, organic fluorophores show a high probability for photobleaching. Luminescent CdSe/ZnS nanocrystals with a hydrophilic shell have been covalently bound to FoF1 either to the stator subunit b or to the rotor subunit c. TIRFM (total internal reflection microscopy) shows that covalent binding of the QD (quantum dot) via cysteine to FoF1 leads to a significant decrease in the blinking probability in the microsecond-to-second time range. This effect allows the observation of subunit movements in an extended time range. If the QD is bound to the rotor subunit c, the fluorescence anisotropy shows fluctuations in the presence of ATP, in contrast with the constant anisotropy observed in the absence of ATP.
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212
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Mahler B, Spinicelli P, Buil S, Quelin X, Hermier JP, Dubertret B. Towards non-blinking colloidal quantum dots. NATURE MATERIALS 2008; 7:659-64. [PMID: 18568030 DOI: 10.1038/nmat2222] [Citation(s) in RCA: 409] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Accepted: 05/19/2008] [Indexed: 05/20/2023]
Abstract
At a single-molecule level, fluorophore emission intensity fluctuates between bright and dark states. These fluctuations, known as blinking, limit the use of fluorophores in single-molecule experiments. The dark-state duration shows a universal heavy-tailed power-law distribution characterized by the occurrence of long non-emissive periods. Here we have synthesized novel CdSe-CdS core-shell quantum dots with thick crystalline shells, 68% of which do not blink when observed individually at 33 Hz for 5 min. We have established a direct correlation between shell thickness and blinking occurrences. Importantly, the statistics of dark periods that appear at high acquisition rates (1 kHz) are not heavy tailed, in striking contrast with previous observations. Blinking statistics are thus not as universal as thought so far. We anticipate that our results will help to better understand the physico-chemistry of single-fluorophore emission and rationalize the design of other fluorophores that do not blink.
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Affiliation(s)
- Benoit Mahler
- Laboratoire Photons Et Matière, CNRS UPR5, ESPCI 10 rue Vauquelin, 75231 Paris, France
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213
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214
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Munro AM, Ginger DS. Photoluminescence quenching of single CdSe nanocrystals by ligand adsorption. NANO LETTERS 2008; 8:2585-2590. [PMID: 18578549 DOI: 10.1021/nl801132t] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We study the effects of octadecanethiol on the photoluminescence intensity and blinking dynamics of single CdSe nanocrystal quantum dots. The number of luminescent nanocrystals per unit area, the intensity histograms of the luminescent nanocrystals, and the single nanocrystal blinking behavior are analyzed in samples with and without added octadecanethiol. We find that the individual nanocrystals within an ensemble do not quench uniformly with thiol addition. The data suggest that the binding of a single octadecanethiol molecule to a CdSe nanocrystal can decrease the photoluminescence quantum yield of that single nanocrystal by at least 50%. These results are important for interpreting photoluminescence-based studies of nanocrystal-ligand binding constants and surface chemistry.
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Affiliation(s)
- Andrea M Munro
- University of Washington, Department of Chemistry, Seattle, Washington 98195-1700, USA
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215
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Galvez EM, Zimmermann B, Rombach-Riegraf V, Bienert R, Gräber P. Fluorescence resonance energy transfer in single enzyme molecules with a quantum dot as donor. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 37:1367-71. [DOI: 10.1007/s00249-008-0351-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 06/02/2008] [Accepted: 06/04/2008] [Indexed: 11/28/2022]
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216
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Abstract
Single-molecule fluorescence resonance energy transfer (smFRET) is one of the most general and adaptable single-molecule techniques. Despite the explosive growth in the application of smFRET to answer biological questions in the last decade, the technique has been practiced mostly by biophysicists. We provide a practical guide to using smFRET, focusing on the study of immobilized molecules that allow measurements of single-molecule reaction trajectories from 1 ms to many minutes. We discuss issues a biologist must consider to conduct successful smFRET experiments, including experimental design, sample preparation, single-molecule detection and data analysis. We also describe how a smFRET-capable instrument can be built at a reasonable cost with off-the-shelf components and operated reliably using well-established protocols and freely available software.
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217
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Biju V, Itoh T, Anas A, Sujith A, Ishikawa M. Semiconductor quantum dots and metal nanoparticles: syntheses, optical properties, and biological applications. Anal Bioanal Chem 2008; 391:2469-95. [PMID: 18548237 DOI: 10.1007/s00216-008-2185-7] [Citation(s) in RCA: 422] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 04/25/2008] [Accepted: 05/13/2008] [Indexed: 12/12/2022]
Abstract
We review the syntheses, optical properties, and biological applications of cadmium selenide (CdSe) and cadmium selenide-zinc sulfide (CdSe-ZnS) quantum dots (QDs) and gold (Au) and silver (Ag) nanoparticles (NPs). Specifically, we selected the syntheses of QDs and Au and Ag NPs in aqueous and organic phases, size- and shape-dependent photoluminescence (PL) of QDs and plasmon of metal NPs, and their bioimaging applications. The PL properties of QDs are discussed with reference to their band gap structure and various electronic transitions, relations of PL and photoactivated PL with surface defects, and blinking of single QDs. Optical properties of Ag and Au NPs are discussed with reference to their size- and shape-dependent surface plasmon bands, electron dynamics and relaxation, and surface-enhanced Raman scattering (SERS). The bioimaging applications are discussed with reference to in vitro and in vivo imaging of live cells, and in vivo imaging of cancers, tumor vasculature, and lymph nodes. Other aspects of the review are in vivo deep tissue imaging, multiphoton excitation, NIR fluorescence and SERS imaging, and toxic effects of NPs and their clearance from the body.
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Affiliation(s)
- Vasudevanpillai Biju
- Nano-Bioanalysis Team, Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 2217-14 Hayashi-cho, Takamatsu, Kagawa, 761-0395, Japan.
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218
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Moeno S, Nyokong T. The photophysical studies of a mixture of CdTe quantum dots and negatively charged zinc phthalocyanines. Polyhedron 2008. [DOI: 10.1016/j.poly.2008.03.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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219
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Joo C, Balci H, Ishitsuka Y, Buranachai C, Ha T. Advances in Single-Molecule Fluorescence Methods for Molecular Biology. Annu Rev Biochem 2008; 77:51-76. [DOI: 10.1146/annurev.biochem.77.070606.101543] [Citation(s) in RCA: 593] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Chirlmin Joo
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801; ,
| | - Hamza Balci
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801; ,
| | - Yuji Ishitsuka
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801; ,
- Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Chittanon Buranachai
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801; ,
| | - Taekjip Ha
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801; ,
- Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801; ,
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220
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Li MJ, Chen Z, Yam VWW, Zu Y. Multifunctional ruthenium(II) polypyridine complex-based core-shell magnetic silica nanocomposites: magnetism, luminescence, and electrochemiluminescence. ACS NANO 2008; 2:905-912. [PMID: 19206487 DOI: 10.1021/nn800123w] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Multifunctional nanoparticles (NPs) that consist of silica-coated magnetic cores and luminescent ruthenium(II) polypyridine complexes have been prepared. These multifunctional nanocomposites were shown to exhibit superparamagnetic behavior, high emission intensity, and electrochemiluminescence. An intense low-oxidation-potential electrochemiluminescence signal was observed by attachment of these functional NPs onto a fluorosurfactant-modified gold (Au(m)) electrode via application of an external magnetic field.
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Affiliation(s)
- Mei-Jin Li
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China
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221
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Ji X, Copenhaver D, Sichmeller C, Peng X. Ligand Bonding and Dynamics on Colloidal Nanocrystals at Room Temperature: The Case of Alkylamines on CdSe Nanocrystals. J Am Chem Soc 2008; 130:5726-35. [DOI: 10.1021/ja710909f] [Citation(s) in RCA: 227] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xiaohui Ji
- Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, AR 72701, and College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Danis Copenhaver
- Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, AR 72701, and College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Christopher Sichmeller
- Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, AR 72701, and College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Xiaogang Peng
- Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, AR 72701, and College of Chemistry, Jilin University, Changchun 130012, P. R. China
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222
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Sukhanova A, Nabiev I. Fluorescent nanocrystal quantum dots as medical diagnostic tools. ACTA ACUST UNITED AC 2008; 2:429-47. [DOI: 10.1517/17530059.2.4.429] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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223
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Chen Y, Vela J, Htoon H, Casson JL, Werder DJ, Bussian DA, Klimov VI, Hollingsworth JA. “Giant” Multishell CdSe Nanocrystal Quantum Dots with Suppressed Blinking. J Am Chem Soc 2008; 130:5026-7. [PMID: 18355011 DOI: 10.1021/ja711379k] [Citation(s) in RCA: 479] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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224
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Zhang CY, Johnson LW. Simple and accurate quantification of quantum dots via single-particle counting. J Am Chem Soc 2008; 130:3750-1. [PMID: 18311984 DOI: 10.1021/ja711493q] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Quantification of quantum dots (QDs) is essential to the quality control of QD synthesis, development of QD-based LEDs and lasers, functionalizing of QDs with biomolecules, and engineering of QDs for biological applications. However, simple and accurate quantification of QD concentration in a variety of buffer solutions and in complex mixtures still remains a critical technological challenge. Here, we introduce a new methodology for quantification of QDs via single-particle counting, which is conceptually different from established UV-vis absorption and fluorescence spectrum techniques where large amounts of purified QDs are needed and specific absorption coefficient or quantum yield values are necessary for measurements. We demonstrate that single-particle counting allows us to nondiscriminately quantify different kinds of QDs by their distinct fluorescence burst counts in a variety of buffer solutions regardless of their composition, structure, and surface modifications, and without the necessity of absorption coefficient and quantum yield values. This single-particle counting can also unambiguously quantify individual QDs in a complex mixture, which is practically impossible for both UV-vis absorption and fluorescence spectrum measurements. Importantly, the application of this single-particle counting is not just limited to QDs but also can be extended to fluorescent microspheres, quantum dot-based microbeads, and fluorescent nano rods, some of which currently lack efficient quantification methods.
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Affiliation(s)
- Chun-yang Zhang
- Department of Chemistry, York College and The Graduate Center, The City University of New York, Jamaica, New York 11451, USA
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225
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Michalet X, Cheng A, Antelman J, Suyama M, Arisaka K, Weiss S. Hybrid photodetector for single-molecule spectroscopy and microscopy. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2008; 6862:68620F_1. [PMID: 21822361 PMCID: PMC3150536 DOI: 10.1117/12.763449] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
We report benchmark tests of a new single-photon counting detector based on a GaAsP photocathode and an electron-bombarded avalanche photodiode developed by Hamamatsu Photonics. We compare its performance with those of standard Geiger-mode avalanche photodiodes. We show its advantages for FCS due to the absence of after-pulsing and for fluorescence lifetime measurements due to its excellent time resolution. Its large sensitive area also greatly simplifies setup alignment. Its spectral sensitivity being similar to that of recently introduced CMOS SPADs, this new detector could become a valuable tool for single-molecule fluorescence measurements, as well as for many other applications.
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Affiliation(s)
- X. Michalet
- Dept. of Chemistry & Biochemistry, University of California at Los Angeles, 607 Charles E Young Drive E, Los Angeles, CA 90095
| | - Adrian Cheng
- Dept. of Physics & Astronomy, University of California at Los Angeles, 405 Hilgard Ave, Los Angeles, CA 90095
| | - Joshua Antelman
- Dept. of Chemistry & Biochemistry, University of California at Los Angeles, 607 Charles E Young Drive E, Los Angeles, CA 90095
| | - Motohiro Suyama
- Electron Tube Division, Hamamatsu Photonics K.K., 315-5 Toyooka village, Iwata-gun 438-0193, Japan
| | - Katsushi Arisaka
- Dept. of Physics & Astronomy, University of California at Los Angeles, 405 Hilgard Ave, Los Angeles, CA 90095
| | - Shimon Weiss
- Dept. of Chemistry & Biochemistry, University of California at Los Angeles, 607 Charles E Young Drive E, Los Angeles, CA 90095
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226
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Martiradonna L, Carbone L, Tandaechanurat A, Kitamura M, Iwamoto S, Manna L, De Vittorio M, Cingolani R, Arakawa Y. Two-dimensional photonic crystal resist membrane nanocavity embedding colloidal dot-in-a-rod nanocrystals. NANO LETTERS 2008; 8:260-264. [PMID: 18095734 DOI: 10.1021/nl0725751] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A novel technique for the fabrication of photonic crystal (PC) nanocavities coupled with colloidal nanocrystals is presented. A waveguiding resist membrane embedding highly emitting dot-in-a-rod nanocrystals was patterned through e-beam lithography and released through wet etching process. The proposed approach makes the PC structure independent of fabrication imperfections induced by etching steps. Micro-photoluminescence spectra revealed degenerated resonant modes (Q-factor approximately 700) whose fabrication-induced spectral splitting is comparable to the full width at half-maximum of the peaks. Active nanocavities tunable from visible to infrared spectral range on GaAs or Si substrates can be easily implemented by this technique.
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Affiliation(s)
- Luigi Martiradonna
- IIS, INQIE, RCAST, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, 153-8904, Tokyo, Japan.
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227
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Fomenko V, Nesbitt DJ. Solution control of radiative and nonradiative lifetimes: a novel contribution to quantum dot blinking suppression. NANO LETTERS 2008; 8:287-93. [PMID: 18095736 DOI: 10.1021/nl0726609] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Time-correlated single photon counting methods are used with confocal microscopy and maximum likelihood estimation analysis to obtain fluorescence lifetime trajectories for single quantum dots with KHz update rates. This technique reveals that control of the solution environment can influence both radiative (k(rad)) and nonradiative (k(nonrad)) pathways for electron-hole recombination emission in a single quantum dot and provides a novel contribution mechanism to nearly complete suppression of quantum dot blinking, specifically by an increase in k(rad*).
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Affiliation(s)
- Vasiliy Fomenko
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA
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228
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Quantum Optics: Colloidal Fluorescent Semiconductor Nanocrystals (Quantum Dots) in Single-Molecule Detection and Imaging. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/978-3-540-73924-1_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
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229
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Kingsley JD, Dou H, Morehead J, Rabinow B, Gendelman HE, Destache CJ. Nanotechnology: a focus on nanoparticles as a drug delivery system. J Neuroimmune Pharmacol 2007; 1:340-50. [PMID: 18040810 DOI: 10.1007/s11481-006-9032-4] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
This review will provide an in-depth discussion on the previous development of nanoparticle-based drug delivery systems (DDS) and discuss original research data that includes the therapeutic enhancement of antiretroviral therapy. The use of nanoparticle DDS will allow practitioners to use drugs to target specific areas of the body. In the treatment of malignancies, the use of nanoparticles as a DDS is making measurable treatment impact. Medical imaging will also utilize DDS to illuminate tumors, the brain, or other cellular functions in the body. The utility of nanoparticle DDS to improve human health is potentially enormous.
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Affiliation(s)
- Jeffrey D Kingsley
- Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha, NE 68198-5215, USA
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230
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McHale K, Berglund AJ, Mabuchi H. Quantum dot photon statistics measured by three-dimensional particle tracking. NANO LETTERS 2007; 7:3535-9. [PMID: 17949048 DOI: 10.1021/nl0723376] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We present an instrument for performing correlation spectroscopy on single fluorescent particles while tracking their Brownian motion in three dimensions using real-time feedback. By tracking CdSe/ZnS quantum dots in water (diffusion coefficient approximately 20 microm2/s), we make the first measurements of photon antibunching (at approximately 10 ns) on single fluorophores free in solution and find fluorescence lifetime heterogeneity within a quantum dot sample. In addition, we show that 2-mercaptoethanol suppresses short time-scale intermittency (1 ms to 1 s) in quantum dot fluorescence by reducing time spent in the off-state.
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Affiliation(s)
- Kevin McHale
- Physical Measurement and Control 266-33, California Institute of Technology, Pasadena, California 91125, USA.
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231
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Mandal A, Nakayama J, Tamai N, Biju V, Isikawa M. Optical and Dynamic Properties of Water-Soluble Highly Luminescent CdTe Quantum Dots. J Phys Chem B 2007; 111:12765-71. [DOI: 10.1021/jp074603+] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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232
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Early KT, McCarthy KD, Hammer NI, Odoi MY, Tangirala R, Emrick T, Barnes MD. Blinking suppression and intensity recurrences in single CdSe-oligo(phenylene vinylene) nanostructures: experiment and kinetic model. NANOTECHNOLOGY 2007; 18:424027. [PMID: 21730460 DOI: 10.1088/0957-4484/18/42/424027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report time-resolved single molecule fluorescence imaging of individual CdSe quantum dots that are functionalized with oligomeric conjugated organic ligands. The fluorescence intensity trajectories from these composite nanostructures display both a strong degree of blinking suppression and intensity fluctuations with characteristic recurrence times on the order of 10-60 s. In addition, fluorescence decay rate measurements of individual hybrid nanostructures indicate significantly modified non-radiative quantum dot decay rates relative to conventional ZnS-capped CdSe quantum dots. We show that a modified diffusive reaction coordinate model with slow fluctuations in quantum dot electron energies (1S(e), 1P(e)) can reproduce the experimentally observed behaviour.
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Affiliation(s)
- K T Early
- George H Richason, Jr Chemistry Research Laboratory, Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
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233
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Fu Y, Zhang J, Lakowicz JR. Suppressed Blinking in Single Quantum Dots (QDs) Immobilized Near Silver Island Films (SIFs). Chem Phys Lett 2007; 447:96-100. [PMID: 18927603 PMCID: PMC2352163 DOI: 10.1016/j.cplett.2007.08.089] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
In this report, we use single-molecule spectroscopic method to study emission behaviors of streptavidin conjugated quantum dots immobilized on biotinylated-BSA (bovine serum albumin) monolayer near non-continuous rough silver nanostructure. We observed greatly reduced blinking and enhanced emission fluorescence of quantum dots next to silver island films.
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Affiliation(s)
- Yi Fu
- Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201
| | - Jian Zhang
- Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201
| | - Joseph R. Lakowicz
- Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, 725 West Lombard Street, Baltimore, MD 21201
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234
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Odoi MY, Hammer NI, Early KT, McCarthy KD, Tangirala R, Emrick T, Barnes MD. Fluorescence lifetimes and correlated photon statistics from single CdSe/oligo(phenylene vinylene) composite nanostructures. NANO LETTERS 2007; 7:2769-73. [PMID: 17655370 DOI: 10.1021/nl0713068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We present measurements of fluorescence intensity trajectories and associated excited-state decay times from individual CdSe/oligo(phenylene vinylene) (CdSe-OPV) quantum dot nanostructures using time-tagged, time-resolved (TTTR) photon counting techniques. We find that fluorescence decay times for the quantum dot emitter in these composite systems are at least an order of magnitude shorter than ZnS-capped CdSe quantum dot systems. We show that both the blinking suppression and associated lifetime/count rate behavior can be described by a modified version of the diffusive reaction coordinate model which couples slow fluctuations in quantum dot electron (1Se, 1Pe) energies to Auger-assisted hole trapping processes, hence modifying both blinking statistics and excited-state decay rates.
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Affiliation(s)
- M Y Odoi
- George R. Richason, Jr. Chemistry Research Laboratory, Department of Chemistry , University of Massachusetts, Amherst, Massachusetts 01003, USA
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235
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S. Lidke D, Nagy P, J. Arndt‐Jovin D. In Vivo Imaging Using Quantum Dot–Conjugated Probes. ACTA ACUST UNITED AC 2007; Chapter 25:Unit 25.1. [DOI: 10.1002/0471143030.cb2501s36] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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236
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Cui B, Wu C, Chen L, Ramirez A, Bearer EL, Li WP, Mobley WC, Chu S. One at a time, live tracking of NGF axonal transport using quantum dots. Proc Natl Acad Sci U S A 2007; 104:13666-71. [PMID: 17698956 PMCID: PMC1959439 DOI: 10.1073/pnas.0706192104] [Citation(s) in RCA: 302] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Retrograde axonal transport of nerve growth factor (NGF) signals is critical for the survival, differentiation, and maintenance of peripheral sympathetic and sensory neurons and basal forebrain cholinergic neurons. However, the mechanisms by which the NGF signal is propagated from the axon terminal to the cell body are yet to be fully elucidated. To gain insight into the mechanisms, we used quantum dot-labeled NGF (QD-NGF) to track the movement of NGF in real time in compartmentalized culture of rat dorsal root ganglion (DRG) neurons. Our studies showed that active transport of NGF within the axons was characterized by rapid, unidirectional movements interrupted by frequent pauses. Almost all movements were retrograde, but short-distance anterograde movements were occasionally observed. Surprisingly, quantitative analysis at the single molecule level demonstrated that the majority of NGF-containing endosomes contained only a single NGF dimer. Electron microscopic analysis of axonal vesicles carrying QD-NGF confirmed this finding. The majority of QD-NGF was found to localize in vesicles 50-150 nm in diameter with a single lumen and no visible intralumenal membranous components. Our findings point to the possibility that a single NGF dimer is sufficient to sustain signaling during retrograde axonal transport to the cell body.
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Affiliation(s)
| | - Chengbiao Wu
- Neurology and Neurological Sciences
- Neuroscience Institute, and
| | - Liang Chen
- Department of Applied Physics, Stanford University, Stanford, CA 94305
| | - Alfredo Ramirez
- Neurology and Neurological Sciences
- Neuroscience Institute, and
| | - Elaine L. Bearer
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI 02910
- Department of Biology, California Institute of Technology, Pasadena, CA 91125
| | - Wei-Ping Li
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - William C. Mobley
- Neurology and Neurological Sciences
- Neuroscience Institute, and
- To whom correspondence may be addressed. E-mail: or
| | - Steven Chu
- Departments of Physics and
- Department of Applied Physics, Stanford University, Stanford, CA 94305
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and
- Departments of Physics and
- Molecular and Cell Biology, University of California, Berkeley, CA 94720
- To whom correspondence may be addressed. E-mail: or
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237
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Abstract
Surface effects significantly influence the functionality of semiconductor nanocrystals. A theoretical understanding of these effects requires an atomic-scale description of the surface. We present an atomistic tight-binding theory of the electronic and optical properties of passivated and unpassivated CdS nanocrystals and CdS/ZnS core/shell nanocrystals. Fully passivated dots, with all dangling bonds saturated, have no surface states in the fundamental band gap, and all near-band-edge states are quantum-confined internal states. When surface anion dangling bonds are unpassivated, an anion-derived, narrow (bandwidth 0.05 eV), surface-state band lies 0.5 eV above the valence band edge, and a broader (0.2 eV) band of back-bonded surface states exists in the gap just above the valence band edge. When surface cation dangling bonds are unpassivated, a broad band of mixed surface/internal states exists above the conduction band edge. Partial passivation can push internal levels above the internal levels of a fully passivated dot or into the band gap. Because of this sensitivity to passivation, explicit models for surface effects are needed to describe accurately internal states. Capping the CdS dot with ZnS reduces the effect of the surface on the internal electronic states and optical properties. Six monolayers of ZnS are needed to eliminate the influence of any surface states on the internal states.
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Affiliation(s)
- Garnett W Bryant
- Atomic Physics Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8423, USA.
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238
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Yu SY, Zhang HJ, Yu JB, Wang C, Sun LN, Shi WD. Bifunctional magnetic-optical nanocomposites: grafting lanthanide complex onto core-shell magnetic silica nanoarchitecture. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:7836-40. [PMID: 17547435 DOI: 10.1021/la700735m] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A new class of bifunctional architecture combining the useful functions of superparamagnetism and terbium complex luminescence into one material has been prepared via two main steps by a modified Stöber method and the layer-by-layer (LbL) assembly technique. The obtained bifunctional nanocomposites exhibit superparamagnetic behavior, high fluorescence intensity, and color purity. The architecture has been characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV-vis absorption and emission spectroscopy, X-ray diffraction, and superconducting quantum interference device (SQUID) magnetometry.
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Affiliation(s)
- Shi-Yong Yu
- Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China
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239
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Hammer NI, Emrick T, Barnes MD. Quantum dots coordinated with conjugated organic ligands: new nanomaterials with novel photophysics. NANOSCALE RESEARCH LETTERS 2007; 2:282. [PMCID: PMC3246356 DOI: 10.1007/s11671-007-9062-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 05/08/2007] [Indexed: 05/23/2023]
Abstract
CdSe quantum dots functionalized with oligo-(phenylene vinylene) (OPV) ligands (CdSe-OPV nanostructures) represent a new class of composite nanomaterials with significantly modified photophysics relative to bulk blends or isolated components. Single-molecule spectroscopy on these species have revealed novel photophysics such as enhanced energy transfer, spectral stability, and strongly modified excited state lifetimes and blinking statistics. Here, we review the role of ligands in quantum dot applications and summarize some of our recent efforts probing energy and charge transfer in hybrid CdSe-OPV composite nanostructures.
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Affiliation(s)
- Nathan I Hammer
- Department of Chemistry, University of Massachusetts, Amherst, MA, 01003, USA
| | - Todd Emrick
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA, 01003, USA
| | - Michael D Barnes
- Department of Chemistry, University of Massachusetts, Amherst, MA, 01003, USA
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240
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van Manen HJ, Otto C. Hybrid confocal Raman fluorescence microscopy on single cells using semiconductor quantum dots. NANO LETTERS 2007; 7:1631-6. [PMID: 17474784 DOI: 10.1021/nl0705945] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We have overcome the traditional incompatibility of Raman microscopy with fluorescence microscopy by exploiting the optical properties of semiconductor fluorescent quantum dots (QDs). Here we present a hybrid Raman fluorescence spectral imaging approach for single-cell microscopy applications. We show that resonant Raman imaging of flavocytochrome b558 at 413.1 nm excitation in QD-labeled neutrophilic granulocytes or nonresonant Raman imaging of proteins and lipids at 647.1 nm excitation in QD-labeled macrophages can be integrated with linear one-photon excitation and nonlinear continuous-wave two-photon excitation fluorescence microscopy of QDs, respectively. The enhanced information content of these two hybrid Raman fluorescence methods provides new multiplexing possibilities for single-cell optical microscopy and intracellular chemical analysis.
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Affiliation(s)
- Henk-Jan van Manen
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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241
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Cai W, Hsu AR, Li ZB, Chen X. Are quantum dots ready for in vivo imaging in human subjects? NANOSCALE RESEARCH LETTERS 2007; 2:265-281. [PMID: 21394238 PMCID: PMC3050636 DOI: 10.1007/s11671-007-9061-9] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2007] [Accepted: 04/24/2007] [Indexed: 04/14/2023]
Abstract
Nanotechnology has the potential to profoundly transform the nature of cancer diagnosis and cancer patient management in the future. Over the past decade, quantum dots (QDs) have become one of the fastest growing areas of research in nanotechnology. QDs are fluorescent semiconductor nanoparticles suitable for multiplexed in vitro and in vivo imaging. Numerous studies on QDs have resulted in major advancements in QD surface modification, coating, biocompatibility, sensitivity, multiplexing, targeting specificity, as well as important findings regarding toxicity and applicability. For in vitro applications, QDs can be used in place of traditional organic fluorescent dyes in virtually any system, outperforming organic dyes in the majority of cases. In vivo targeted tumor imaging with biocompatible QDs has recently become possible in mouse models. With new advances in QD technology such as bioluminescence resonance energy transfer, synthesis of smaller size non-Cd based QDs, improved surface coating and conjugation, and multifunctional probes for multimodality imaging, it is likely that human applications of QDs will soon be possible in a clinical setting.
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Affiliation(s)
- Weibo Cai
- The Molecular Imaging Program at Stanford (MIPS), Department of Radiology and Bio-X Program, Stanford University School of Medicine, 1201 Welch Rd, P095, Stanford, CA, 94305-5484, USA
| | - Andrew R Hsu
- The Molecular Imaging Program at Stanford (MIPS), Department of Radiology and Bio-X Program, Stanford University School of Medicine, 1201 Welch Rd, P095, Stanford, CA, 94305-5484, USA
| | - Zi-Bo Li
- The Molecular Imaging Program at Stanford (MIPS), Department of Radiology and Bio-X Program, Stanford University School of Medicine, 1201 Welch Rd, P095, Stanford, CA, 94305-5484, USA
| | - Xiaoyuan Chen
- The Molecular Imaging Program at Stanford (MIPS), Department of Radiology and Bio-X Program, Stanford University School of Medicine, 1201 Welch Rd, P095, Stanford, CA, 94305-5484, USA
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242
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Chung E, Kim D, Cui Y, Kim YH, So PTC. Two-dimensional standing wave total internal reflection fluorescence microscopy: superresolution imaging of single molecular and biological specimens. Biophys J 2007; 93:1747-57. [PMID: 17483188 PMCID: PMC1948056 DOI: 10.1529/biophysj.106.097907] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The development of high resolution, high speed imaging techniques allows the study of dynamical processes in biological systems. Lateral resolution improvement of up to a factor of 2 has been achieved using structured illumination. In a total internal reflection fluorescence microscope, an evanescence excitation field is formed as light is total internally reflected at an interface between a high and a low index medium. The <100 nm penetration depth of evanescence field ensures a thin excitation region resulting in low background fluorescence. We present even higher resolution wide-field biological imaging by use of standing wave total internal reflection fluorescence (SW-TIRF). Evanescent standing wave (SW) illumination is used to generate a sinusoidal high spatial frequency fringe pattern on specimen for lateral resolution enhancement. To prevent thermal drift of the SW, novel detection and estimation of the SW phase with real-time feedback control is devised for the stabilization and control of the fringe phase. SW-TIRF is a wide-field superresolution technique with resolution better than a fifth of emission wavelength or approximately 100 nm lateral resolution. We demonstrate the performance of the SW-TIRF microscopy using one- and two-directional SW illumination with a biological sample of cellular actin cytoskeleton of mouse fibroblast cells as well as single semiconductor nanocrystal molecules. The results confirm the superior resolution of SW-TIRF in addition to the merit of a high signal/background ratio from TIRF microscopy.
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Affiliation(s)
- Euiheon Chung
- Harvard-Massachusetts Institutes of Technology, Division of Health Sciences and Technology, Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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243
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Tachikawa T, Chung HR, Masuhara A, Kasai H, Oikawa H, Nakanishi H, Fujitsuka M, Majima T. In situ and ex situ observations of the growth dynamics of single perylene nanocrystals in water. J Am Chem Soc 2007; 128:15944-5. [PMID: 17165701 DOI: 10.1021/ja0654276] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The growth dynamics of fluorescent perylene nanocrystals, which are fabricated by the reprecipitation method, was investigated using in situ and ex situ single-particle fluorescence measurements. A red shift in the emission maxima as the aging time increased was observed by single-particle fluorescence spectral measurements. The number and size of the nanocrystals increased with the increasing aging time in water. It was concluded that the metastable intermediates, such as clusters and initial nanoparticles, are relevant for the early stages of nucleation and growth of the perylene nanocrystals.
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Affiliation(s)
- Takashi Tachikawa
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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244
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Ai X, Xu Q, Jones M, Song Q, Ding SY, Ellingson RJ, Himmel M, Rumbles G. Photophysics of (CdSe)ZnS colloidal quantum dots in an aqueous environment stabilized with amino acids and genetically-modified proteins. Photochem Photobiol Sci 2007; 6:1027-33. [PMID: 17721603 DOI: 10.1039/b706471c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using a combination of two amino acids, histidine and N-acetyl-cysteine, to replace the original organic capping groups of (CdSe)ZnS quantum dots, water-soluble and highly luminescent (CdSe)ZnS quantum dots have been successfully prepared at pH 8. Characterization by steady-state and time-resolved photoluminescence spectroscopy, and transient absorption spectroscopy, demonstrate that the electronic properties of these quantum dots exceed those of the original as-synthesized samples dissolved in a more-conventional organic solvent. Furthermore, these amino acid-stabilized quantum dots have been assembled onto a cellulose substrate via cellulose binding proteins that specifically bind to cellulose and was genetically engineered to harbor dual hexahistidine tags at the N- and C-termini to confer binding with the zinc(II) on the quantum dot surface. The spectroscopic measurements show that the protein-bound quantum dots continue to retain their desirable electronic properties when bound on the substrate. Meanwhile, the specific and very selective binding properties of the proteins have remained effective.
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Affiliation(s)
- Xin Ai
- National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO 80401-3393, USA
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245
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Mondéjar SP, Kovtun A, Epple M. Lanthanide-doped calcium phosphate nanoparticles with high internal crystallinity and with a shell of DNA as fluorescent probes in cell experiments. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b708258d] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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246
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Heuff RF, Swift JL, Cramb DT. Fluorescence correlation spectroscopy using quantum dots: advances, challenges and opportunities. Phys Chem Chem Phys 2007; 9:1870-80. [PMID: 17431516 DOI: 10.1039/b617115j] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Semiconductor nanocrystals (quantum dots) have been increasingly employed in measuring the dynamic behavior of biomacromolecules using fluorescence correlation spectroscopy. This poses a challenge, because quantum dots display their own dynamic behavior in the form of intermittent photoluminescence, also known as blinking. In this review, the manifestation of blinking in correlation spectroscopy will be explored, preceded by an examination of quantum dot blinking in general.
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Affiliation(s)
- Romey F Heuff
- Department of Chemistry, University of Calgary, 2500 University Dr NW, Calgary, AB, Canada T2N 1N4
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247
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Abstract
The emerging nanomaterial, quantum dots or QDs, offers numerous potential applications in the biological area. As cell labeling probes, QDs become now an alternative of existing organic fluorescent dyes and fluorescent proteins. In this short review, we cover typical and successful applications of QDs as fluorescent probes in cell labeling and genomic diagnosis. As a future important application, biomolecular detection at a single molecule level utilizing QDs is also discussed.
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Affiliation(s)
- Noritada Kaji
- Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Japan.
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248
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Jonas M, Yao Y, So PTC, Dewey CF. Detecting Single Quantum Dot Motion With Nanometer Resolution for Applications in Cell Biology. IEEE Trans Nanobioscience 2006; 5:246-50. [PMID: 17181023 DOI: 10.1109/tnb.2006.886559] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Quantum dots (QDs), semiconductor particles of nanometer dimension, have emerged as excellent fluorescent analogs in tracer experiments with single molecule sensitivity for bioassays. Cell imaging greatly benefits from the remarkable optical and physical properties of these inorganic nanocrystals: QDs are much brighter and exhibit a higher resistance to photobleaching than traditional fluorophores, and their narrow emission spectrum and flexible surface chemistry make them particularly suitable for multiplex imaging. Here, we have demonstrated the achievement of a nanometer spatial resolution on the position of a single QD in a simple optomechanical instrument using a high-sensitivity low-noise detector, an intensified CCD camera. Furthermore, nanometer variations in the amplitude of a QD's sinusoidal oscillations could be quantitatively distinguished after fast Fourier transform (FFT) based data processing. As confirmed by experiments where QDs were attached to the surface of bovine aortic endothelial cells, this method can be exploited in biology to assess molecular and subcellular contributions to responses such as motility, intracellular trafficking, and mechanotransduction, with high resolution and minimal disturbance to cells.
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Affiliation(s)
- Maxine Jonas
- Department of Biological Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
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249
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Li-Shishido S, Watanabe TM, Tada H, Higuchi H, Ohuchi N. Reduction in nonfluorescence state of quantum dots on an immunofluorescence staining. Biochem Biophys Res Commun 2006; 351:7-13. [PMID: 17055452 DOI: 10.1016/j.bbrc.2006.09.159] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Accepted: 09/22/2006] [Indexed: 11/21/2022]
Abstract
Fluorescence quantum dots are widely used in immunofluorescence staining because of their intense and stable fluorescence. However, the nonfluorescence state of the quantum dots is their disadvantage. Here, the nonfluorescence state of the dots labeled to cells and tissues was suppressed. Cells and tissues where the receptor HER2 had been overexpressed were fixed and then labeled with anti-HER2 crosslinked with the dots. The intensity of the dots increased with the illumination time. The majority of the single dots were in the nonfluorescence state at beginning of the illumination period and the number of fluorescence dots observed increased with the illumination time. Living cells were also labeled with the anti-HER2-Qdots. Blinking and bleaching of the Qdots was effectively suppressed by adding beta-mercaptoethanol and glutathione. Therefore, the movement of the Qdots bound to cell membrane could be observed for long periods of time.
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Affiliation(s)
- Songhua Li-Shishido
- Division of Surgical Oncology, Graduate School of Medicine, Tohoku University, Japan
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Mei E, Hochstrasser RM. High-Resolution Optical Imaging from Trajectory Time Distributions. J Phys Chem B 2006; 110:25101-7. [PMID: 17149935 DOI: 10.1021/jp065142f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Trajectory time distribution optical microscopy (TTDOM), which records the mean off-times of single molecular fluorescent indicators that light up when they collide with vesicles, is extended to record fluorescence durations or on-times. TTDOM can distinguish shapes of objects that are smaller than the diffraction limited resolution. The fluorescence duration time image can also provide high-resolution information. The effects of the threshold that separates fluorescent bursts from background signals and of two or more probes visiting the vesicles simultaneously have been investigated systematically. New experimental results along with simulations indicate that TTDOM is capable of providing the size and shape of objects and information on probe-vesicle binding.
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Affiliation(s)
- Erwen Mei
- Chemistry Department, University of Pennsylvania, Philadelphia, Pennsylvania 19014, USA
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