251
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He H, Qian H, Dong C, Wang K, Ren J. Single Nonblinking CdTe Quantum Dots Synthesized in Aqueous Thiopropionic Acid. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200602758] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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252
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He H, Qian H, Dong C, Wang K, Ren J. Single Nonblinking CdTe Quantum Dots Synthesized in Aqueous Thiopropionic Acid. Angew Chem Int Ed Engl 2006; 45:7588-91. [PMID: 17054303 DOI: 10.1002/anie.200602758] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Hua He
- College of Chemistry & Chemical Engineering, Shanghai Jiaotong University, Shanghai 200240, China
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253
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Wang S, Querner C, Emmons T, Drndic M, Crouch CH. Fluorescence Blinking Statistics from CdSe Core and Core/Shell Nanorods. J Phys Chem B 2006; 110:23221-7. [PMID: 17107169 DOI: 10.1021/jp064976v] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report fluorescence blinking statistics measured from single CdSe nanorods (NRs) of seven different sizes with aspect ratios ranging from 3 to 11. This study also included core/shell CdSe/ZnSe NRs and core NRs with two different surface ligands producing different degrees of surface passivation. We compare the findings for NRs to our measurements of blinking statistics from spherical CdSe core and CdSe/ZnS core/shell nanocrystals (NCs). We find that, for both NRs and spherical NCs, the off-time probability distributions are well described by a power law, while the on-time probability distributions are best described by a truncated power law, P(tau(on)) approximately tau(on)(-alpha)e((-tau)(on)/(tau)(c)). The measured crossover time, tau(c), is indistinguishable within experimental uncertainty for core and core/shell NRs, as well as for core NRs with different ligands, for the same core size, indicating that surface passivation does not affect the blinking statistics significantly. We find that, at fixed excitation intensity, 1/tau(c) increases approximately linearly with increasing NR aspect ratio; for a given sample, 1/tau(c) increases very gradually with increasing excitation intensity. Examining 1/tau(c)versus the single-particle photon absorption rate for all samples indicates that the change in NR absorption cross section with sample size can account for some but not all of the differences in crossover time. This suggests that the degree of quantum confinement may be partially responsible for the aspect ratio dependence of the crossover time.
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Affiliation(s)
- Siying Wang
- Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104, USA
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254
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Aryal BP, Neupane KP, Sandros MG, Benson DE. Metallothioneins initiate semiconducting nanoparticle cellular toxicity. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2006; 2:1159-63. [PMID: 17193582 DOI: 10.1002/smll.200500527] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Affiliation(s)
- Baikuntha P Aryal
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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255
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Gómez DE, Califano M, Mulvaney P. Optical properties of single semiconductor nanocrystals. Phys Chem Chem Phys 2006; 8:4989-5011. [PMID: 17091151 DOI: 10.1039/b607661k] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present an overview of the current progress in the understanding of the (steady state) optical properties of individual II-VI semiconductor nanocrystals. We begin with a presentation of the conceptual development of the theory required to model the electronic structure of these systems. This is followed by an overview of the current experimental results obtained from the spectroscopy of individual semiconductor nanocrystals, and in particular, we focus on the study of photoluminescence intermittency (blinking) and spectral diffusion. Where possible, we link the experimental observations to the predictions of current theories. We conclude that the surface of small semiconductor crystals plays an important role in determining their optical properties.
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Affiliation(s)
- Daniel E Gómez
- School of Chemistry, The University of Melbourne, Parkville, VIC 3010, Australia
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256
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Lagerholm BC, Averett L, Weinreb GE, Jacobson K, Thompson NL. Analysis method for measuring submicroscopic distances with blinking quantum dots. Biophys J 2006; 91:3050-60. [PMID: 16861265 PMCID: PMC1578492 DOI: 10.1529/biophysj.105.079178] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A method is described that takes advantage of the intermittency ("blinking") in the fluorescence of quantum dots (QDs) to measure absolute positions of closely spaced QDs. The concept is that even if two QDs are separated by only tens of nanometers, the position of each QD is resolvable if the point spread function of each can be imaged independently of the other. In the case of QDs, this is possible if each QD separately blinks completely on and off during a time-lapse sequence. To demonstrate the principle of this method, time-lapse sequences of single blinking QDs were acquired and the centroids of the point spread functions determined. Images of the blinking QDs were then overlapped in software, pixel by pixel, generating a range of submicroscopic distances between QD pairs. Methods were developed for analyzing the overlapped time sequences of the QD pairs so that the positions of the QDs and the distances between them could be determined without prior knowledge of the single QD positions. We subsequently used this method to measure the end-to-end length of a 122-basepair double-stranded DNA fragment.
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Affiliation(s)
- B Christoffer Lagerholm
- Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA
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257
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Bentolila LA, Weiss S. Single-step multicolor fluorescence in situ hybridization using semiconductor quantum dot-DNA conjugates. Cell Biochem Biophys 2006; 45:59-70. [PMID: 16679564 PMCID: PMC3084375 DOI: 10.1385/cbb:45:1:59] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
We report a rapid method for the direct multicolor imaging of multiple subnuclear genetic sequences using novel quantum dot-based fluorescence in situ hybridization (FISH) probes (QD-FISH). Short DNA oligonucleotides were attached on QDs and used in a single hybridization/detection step of target sites in situ. QD-FISH probes penetrate both intact interphase nuclei and metaphase chromosomes and showed good targeting of dense chromatin domains with minimal steric hindrances. We further demonstrated that QD's broad absorption spectra allowed different colored probes specific for distinct subnuclear genetic sequences to be simultaneously excited with a single excitation wavelength and imaged free of chromatic aberrations in a single exposure. Thus, these results demonstrate that QD-FISH probes are very effective in multicolor FISH applications. This work also documents new possibilities of using QD-FISH probes detection down to the single molecule level.
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Affiliation(s)
- Laurent A Bentolila
- Department of Chemistry and Biochemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095-1569, USA.
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258
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Hammer NI, Early KT, Sill K, Odoi MY, Emrick T, Barnes MD. Coverage-Mediated Suppression of Blinking in Solid State Quantum Dot Conjugated Organic Composite Nanostructures. J Phys Chem B 2006; 110:14167-71. [PMID: 16854115 DOI: 10.1021/jp062065f] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Size-correlated single-molecule fluorescence measurements on CdSe quantum dots functionalized with oligo(phenylene vinylene) (OPV) ligands exhibit modified fluorescence intermittency (blinking) statistics that are highly sensitive to the degree of ligand coverage on the quantum dot surface. As evidenced by a distinct surface height signature, fully covered CdSe-OPV nanostructures (approximately 25 ligands) show complete suppression of blinking in the solid state on an integration time scale of 1 s. Some access to dark states is observed on finer time scales (100 ms) with average persistence times significantly shorter than those from ZnS-capped CdSe quantum dots. This effect is interpreted as resulting from charge transport from photoexcited OPV into vacant trap sites on the quantum dot surface. These results suggest exciting new applications of composite quantum dot/organic systems in optoelectronic systems.
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Affiliation(s)
- Nathan I Hammer
- The George Richason, Jr. Chemistry Research Laboratory, Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
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259
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Abstract
Colloidal semiconductor quantum dots are promising for single-molecule biological imaging due to their outstanding brightness and photostability. As a proof of concept for single-molecule fluorescence resonance energy transfer (FRET) applications, we measured FRET between a single quantum dot and a single organic fluorophore Cy5. DNA Holliday junction dynamics measured with the quantum dot/Cy5 pair are identical to those obtained with the conventional Cy3/Cy5 pair, that is, conformational changes of individual molecules can be observed by using the quantum dot as the donor.
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Affiliation(s)
- Sungchul Hohng
- Physics Department, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801, USA
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260
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Clark J, Smith SS. Application of Nanoscale Bioassemblies to Clinical Laboratory Diagnostics. Adv Clin Chem 2006; 41:23-48. [PMID: 28682750 DOI: 10.1016/s0065-2423(05)41002-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This chapter summarizes progress in several approaches and devices that will improve and augment existing diagnostic techniques. The term bionanotechnology has been used to describe the science that supports the construction of nanoscale bioassemblies. In each of the present applications to diagnostics, bionanotechnological devices play a largely passive role. Cell surface targeting with an antibody, a growth factor, or a small molecule ligand achieves a new level of sophistication, however, it is still a passive approach. While the induced conformational changes associated with the binding of dendrimers or molecular beacons are somewhat more complex responses to the local environment, they are still largely passive mechanistically. Dynamic devices that change color with time of incubation based on the presence or absence of secondary or tertiary cellular markers within a population exhibiting a primary marker would be of considerable utility. Dynamic nanoscale devices of this type await the application of the rules of assembly associated with the scaffolds described earlier and perhaps the discovery and application of new rules of assembly and new scaffolds.
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Affiliation(s)
- Jarrod Clark
- City of Hope National Medical Center and Beckman Research Institute, Duarte, California
| | - Steven S Smith
- City of Hope National Medical Center and Beckman Research Institute, Duarte, California
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261
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Muthukrishnan G, Hutchins BM, Williams ME, Hancock WO. Transport of semiconductor nanocrystals by kinesin molecular motors. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2006; 2:626-30. [PMID: 17193098 DOI: 10.1002/smll.200500223] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Affiliation(s)
- Gayatri Muthukrishnan
- Department of Bioengineering, 229 Hallowell Bldg. The Pennsylvania State University, University Park, PA 16802, USA
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262
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Pinaud F, Michalet X, Bentolila LA, Tsay JM, Doose S, Li JJ, Iyer G, Weiss S. Advances in fluorescence imaging with quantum dot bio-probes. Biomaterials 2006; 27:1679-87. [PMID: 16318871 PMCID: PMC3073483 DOI: 10.1016/j.biomaterials.2005.11.018] [Citation(s) in RCA: 272] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Accepted: 11/11/2005] [Indexed: 10/25/2022]
Abstract
After much effort in surface chemistry development and optimization by several groups, fluorescent semiconductor nanocrystals probes, also known as quantum dots or qdots, are now entering the realm of biological applications with much to offer to biologists. The road to success has been paved with hurdles but from these efforts has stemmed a multitude of original surface chemistries that scientists in the biological fields can draw from for their specific biological applications. The ability to easily modulate the chemical nature of qdot surfaces by employing one or more of the recently developed qdot coatings, together with their exceptional photophysics have been key elements for qdots to acquire a status of revolutionary fluorescent bio-probes. Indeed, the unique properties of qdots not only give biologists the opportunity to explore advanced imaging techniques such as single molecule or lifetime imaging but also to revisit traditional fluorescence imaging methodologies and extract yet unobserved or inaccessible information in vitro or in vivo.
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Affiliation(s)
- Fabien Pinaud
- Department of Chemistry & Biochemistry, UCLA, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA.
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263
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Biebricher A, Sauer M, Tinnefeld P. Radiative and Nonradiative Rate Fluctuations of Single Colloidal Semiconductor Nanocrystals. J Phys Chem B 2006; 110:5174-8. [PMID: 16539443 DOI: 10.1021/jp060660b] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Spectrally and time-resolved single-molecule fluorescence spectroscopy was used to investigate fluctuations of the photophysical characteristics of different types of semiconductor nanocrystals (NCs) at room temperature. Correlation of photoluminescence (PL) emission maxima, decay time, and intensity of individual NCs with millisecond time resolution reveals new sources of intensity fluctuations and photophysical properties. In particular, we demonstrate that independent of quenched states spectral diffusion is associated with changes of the radiative rate constant k(r) by means of the quantum-confined Stark effect. Correlation of the different photophysical parameters revealed an intrinsic nonradiative rate and enabled the disentangling of intrinsic and extrinsic nonradiative rate constants. Moreover, it allowed us to assess the PL quantum yield of single NCs. Finally, the presented technique was successfully applied to demonstrate that the addition of antiblinking reagents such as mercaptoethylamine accelerates the observed fluctuations between different photophysical states.
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264
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Odoi MY, Hammer NI, Sill K, Emrick T, Barnes MD. Observation of Enhanced Energy Transfer in Individual Quantum Dot−Oligophenylene Vinylene Nanostructures. J Am Chem Soc 2006; 128:3506-7. [PMID: 16536509 DOI: 10.1021/ja058429j] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The temporal and spectral properties of luminescence from individual CdSe quantum dot-oligophenylene vinylene nanostructures (single quantum dots with conjugated organic ligands coordinated to the surface) are profoundly modified relative to blended films of the same components. These kinds of composite quantum dot-conjugated organic systems have attracted significant interest as a way to improve efficiency in photovoltaic device applications. By direct functionalization of the dot surface with the conjugated organic ligands, we realize a significant enhancement in energy transfer and luminescence stability.
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Affiliation(s)
- Michael Y Odoi
- The George R. Richason Jr. Chemistry Research Laboratory, Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003-9336, USA
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265
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Swift JL, Heuff R, Cramb DT. A two-photon excitation fluorescence cross-correlation assay for a model ligand-receptor binding system using quantum dots. Biophys J 2006; 90:1396-410. [PMID: 16299079 PMCID: PMC1367290 DOI: 10.1529/biophysj.105.069526] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Accepted: 10/27/2005] [Indexed: 11/18/2022] Open
Abstract
Two-photon excitation fluorescence cross-correlation spectroscopy (TPE-XCS) is a very suitable method for studying interactions of two distinctly labeled fluorescent molecules. As such, it lends itself nicely to the study of ligand-receptor interactions. By labeling the ligand with one color of fluorescent dye and the receptor with another, it is possible to directly monitor ligand binding rather than inferring binding by monitoring downstream effects. One challenge of the TPE-XCS approach is that of separating the signal due to the receptor from that of the ligand. Using standard organic fluorescent labels there is almost inevitably spectral cross talk between the detection channels, which must be accounted for in TPE-XCS data analysis. However, using quantum dots as labels for both ligand and receptor this limitation can be alleviated, because of the dot's narrower emission spectra. Using solely quantum dots as fluorescent labels is a novel approach to TPE-XCS, which may be generalizable to many pairs of interacting biomolecules after the proof of principle and the assessment of limitations presented here. Moreover, it is essential that relevant pharmacological parameters such as the equilibrium dissociation constant, K(d), can be easily extracted from the XCS data with minimal processing. Herein, we present a modified expression for fractional occupancy based on the auto- and cross-correlation decays obtained from a well-defined ligand-receptor system. Nanocrystalline semiconductor quantum dots functionalized with biotin (lambda(em) = 605 nm) and streptavidin (lambda(em) = 525 nm) were used for which an average K(d) value of 0.30 +/- 0.04 x 10(-9) M was obtained (cf. native system approximately 10(-15)). Additionally, the off-rate coefficient (k(off)) for dissociation of the two quantum dots was determined as 5 x 10(-5) s(-1). This off-rate is slightly larger than for native biotin-streptavidin (5 x 10(-6) s(-1)); the bulky nature of the quantum dots and restricted motion/orientation of functionalized dots in solution can account for differences in the streptavidin-biotin mediated dot-dot binding compared with those for native streptavidin-biotin.
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Affiliation(s)
- J L Swift
- Department of Chemistry, University of Calgary, Calgary AB, T2N 1N4, Canada
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266
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Willard DM, Mutschler T, Yu M, Jung J, Van Orden A. Directing energy flow through quantum dots: towards nanoscale sensing. Anal Bioanal Chem 2006; 384:564-71. [PMID: 16440194 DOI: 10.1007/s00216-005-0250-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Revised: 11/22/2005] [Accepted: 11/23/2005] [Indexed: 11/28/2022]
Abstract
Nanoscale sensors can be created when an expected energetic pathway is created and then that pathway is either initiated or disrupted by a specific binding event. Constructing the sensor on the nanoscale could lead to greater sensitivity and lower limits of detection. To this end, quantum dots (QDs) can be considered prime candidates for the active components. Relative to organic chromophores, QDs have tunable spectral properties, show less susceptibility to photobleaching, have similar brightness, and have been shown to display electro-optical properties. In this review, we discuss recent articles that incorporate QDs into directed energy flow systems, some with the goal of building new and more powerful sensors and others that could lead to more powerful sensors.
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Affiliation(s)
- Dale M Willard
- Chemistry Department, Colorado State University, Fort Collins, CO 80523-1872, USA
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267
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Seitz A, Surrey T. Processive movement of single kinesins on crowded microtubules visualized using quantum dots. EMBO J 2006; 25:267-77. [PMID: 16407972 PMCID: PMC1383520 DOI: 10.1038/sj.emboj.7600937] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Accepted: 12/06/2005] [Indexed: 11/09/2022] Open
Abstract
Kinesin-1 is a processive molecular motor transporting cargo along microtubules. Inside cells, several motors and microtubule-associated proteins compete for binding to microtubules. Therefore, the question arises how processive movement of kinesin-1 is affected by crowding on the microtubule. Here we use total internal reflection fluorescence microscopy to image in vitro the runs of single quantum dot-labelled kinesins on crowded microtubules under steady-state conditions and to measure the degree of crowding on a microtubule at steady-state. We find that the runs of kinesins are little affected by high kinesin densities on a microtubule. However, the presence of high densities of a mutant kinesin that is not able to step efficiently reduces the average speed of wild-type kinesin, while hardly changing its processivity. This indicates that kinesin waits in a strongly bound state on the microtubule when encountering an obstacle until the obstacle unbinds and frees the binding site for kinesin's next step. A simple kinetic model can explain quantitatively the behaviour of kinesin under both crowding conditions.
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Affiliation(s)
- Arne Seitz
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Heidelberg, Germany
| | - Thomas Surrey
- European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Heidelberg, Germany
- EMBL, Cell Biology and Biophysics Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany. Tel.: +49 6221 387 8360; Fax: +49 6221 387 8512; E-mail:
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268
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Yeow EKL, Melnikov SM, Bell TDM, De Schryver FC, Hofkens J. Characterizing the Fluorescence Intermittency and Photobleaching Kinetics of Dye Molecules Immobilized on a Glass Surface. J Phys Chem A 2006; 110:1726-34. [PMID: 16451001 DOI: 10.1021/jp055496r] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The blinking behavior of single Atto565 molecules on a glass surface is studied under air or nitrogen atmospheres using confocal microscopy. The broad distributions for both on- and off-time durations obey power law kinetics that are rationalized using a charge tunneling model. In this case, a charge is transferred from the Atto565 molecule to localized states found on the glass surface. Subsequent charge recombination by back charge tunneling from trap to Atto565 cation (i.e., dark state) restores the fluorescence. The off-time distribution is independent of excitation intensity (I), whereas the on-time distribution exhibits a power law exponent that varies with I. Two pathways have been identified to lead to the formation of the radical dark state. The first involves direct charge tunneling from the excited singlet S1 state to charge traps in the surrounding matrix, and the second requires charge ejection from the triplet T1 state after intersystem crossing from S1. Monte Carlo simulation studies complement the two-pathway model. Photobleaching curves of both single and ensemble molecules do not exhibit monoexponential decays suggesting complex bleaching dynamics arising from triplet and radical states.
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Affiliation(s)
- Edwin K L Yeow
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium.
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269
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Chung I, Witkoskie JB, Cao J, Bawendi MG. Description of the fluorescence intensity time trace of collections of CdSe nanocrystal quantum dots based on single quantum dot fluorescence blinking statistics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:011106. [PMID: 16486121 DOI: 10.1103/physreve.73.011106] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Indexed: 05/06/2023]
Abstract
This paper analyzes the observed phenomenology of the fluorescence time trace of collections of quantum dots (QDs) in terms of the model parameters that characterize the fluorescence blinking statistics of single QDs. We demonstrate that the non-universal dynamics that appear in fluorescence time traces of collections of QDs at short time scales are related to the universal dynamics that appear at longer time scales. We explore how the extent of time separation between the short and long dynamics affects the transition region and the dynamics at longer time scales. We suggest a methodology to extract single QD statistical model parameters from experimental fluorescence time traces of collections of QDs. We explore theoretical time traces and their experimental analogs for three different cases that span the diverse nonuniversal dynamics that appear at short time scales.
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Affiliation(s)
- Inhee Chung
- Department of Chemistry and Center for Materials Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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270
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Ishikawa M. ELECTROCHEMISTRY 2006; 74:501-506. [DOI: 10.5796/electrochemistry.74.501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] Open
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271
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Nan X, Sims PA, Chen P, Xie XS. Observation of Individual Microtubule Motor Steps in Living Cells with Endocytosed Quantum Dots. J Phys Chem B 2005; 109:24220-4. [PMID: 16375416 DOI: 10.1021/jp056360w] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the observation of individual steps taken by motor proteins in living cells by following movements of endocytic vesicles that contain quantum dots (QDs) with a fast camera. The brightness and photostability of quantum dots allow us to record motor displacement traces with 300 micros time resolution and 1.5 nm spatial precision. We observed individual 8 nm steps in active transport toward both the microtubule plus- and minus-ends, the directions of kinesin and dynein movements, respectively. In addition, we clearly resolved abrupt 16 nm steps in the plus-end direction and often consecutive 16 nm and occasional 24 nm steps in minus-end directed movements. This work demonstrates the ability of the QD assay to probe the operation of motor proteins at the molecular level in living cells under physiological conditions.
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Affiliation(s)
- Xiaolin Nan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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272
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Nakashima T, Sakakibara T, Kawai T. Highly Luminescent CdTe Nanocrystal–Polymer Composites Based on Ionic Liquid. CHEM LETT 2005. [DOI: 10.1246/cl.2005.1410] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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273
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Abstract
Robust and bright light emitters, semiconductor nanocrystals [quantum dots (QDs)] have been adopted as a new class of fluorescent labels. Six years after the first experiments of their uses in biological applications, there have been dramatic improvements in understanding surface chemistry, biocompatibility, and targeting specificity. Many studies have shown the great potential of using quantum dots as new probes in vitro and in vivo. This review summarizes the recent advances of quantum dot usage at the cellular level, including immunolabeling, cell tracking, in situ hybridization, FRET, in vivo imaging, and other related technologies. Limitations and potential future uses of quantum dot probes are also discussed.
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Affiliation(s)
- A Paul Alivisatos
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
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274
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Yao J, Larson DR, Vishwasrao HD, Zipfel WR, Webb WW. Blinking and nonradiant dark fraction of water-soluble quantum dots in aqueous solution. Proc Natl Acad Sci U S A 2005; 102:14284-9. [PMID: 16169907 PMCID: PMC1242317 DOI: 10.1073/pnas.0506523102] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Water-soluble quantum dots (qdots) are now being used in life sciences research to take advantage of their bright, easily excited fluorescence and high photostability. Although the frequent erratic blinking and substantial dark (never radiant) fractions that occur in all available qdots may interfere with many applications, these properties of individual particles in biological environments had not been fully evaluated. By labeling Qdot-streptavidin with organic dyes, we were able to distinguish individual dark and bright qdots and to observe blinking events as qdots freely diffused in aqueous solution. Bright fractions were measured by confocal fluorescence coincidence analysis (CFCA) and two-photon cross-correlation fluorescence correlation spectroscopy (FCS). The observed bright fractions of various preparations were proportional to the ensemble quantum yields (QYs), but the intrinsic brightness of individual qdots was found to be constant across samples with different QYs but the same emission wavelengths. Increasing qdots' illuminated dwell time by 10-fold during FCS did not change the fraction of apparently dark qdots but did increase the detected fraction of blinking qdots, suggesting that the dark population does not arise from millisecond blinking. Combining CFCA with wide-field imaging of arrays of qdots localized in dilute agarose gel, the blinking of qdots was measured across five orders of magnitude in time: approximately 0.001-100 s. This research characterizes photophysical pathologies of qdots in biologically relevant environments rather than adhered on dielectric surfaces and describes methods that are useful for studying various bioapplicable nanoparticles.
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Affiliation(s)
- Jie Yao
- School of Applied and Engineering Physics and Field of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA
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275
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Ding SY, Smith S, Xu Q, Sugiyama J, Jones M, Rumbles G, Bayer EA, Himmel ME. Ordered arrays of quantum dots using cellulosomal proteins. Ind Biotechnol (New Rochelle N Y) 2005. [DOI: 10.1089/ind.2005.1.198] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Shi-You Ding
- National Bioenergy Center, Basic Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401
| | - Steven Smith
- National Bioenergy Center, Basic Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401
| | - Qi Xu
- National Bioenergy Center, Basic Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401
| | - Junji Sugiyama
- Research Institute of Sustainable Humanosphere, Kyoto University, Gokanosho, Uji, Kyoto, 611-0011, Japan
| | - Marcus Jones
- National Bioenergy Center, Basic Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401
| | - Garry Rumbles
- National Bioenergy Center, Basic Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401
| | - Edward A. Bayer
- Weizmann Institute of Science, Dept. of Biological Chemistry, Rehovot 76100, Israel
| | - Michael E. Himmel
- National Bioenergy Center, Basic Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401
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276
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Biju V, Makita Y, Nagase T, Yamaoka Y, Yokoyama H, Baba Y, Ishikawa M. Subsecond Luminescence Intensity Fluctuations of Single CdSe Quantum Dots. J Phys Chem B 2005; 109:14350-5. [PMID: 16852805 DOI: 10.1021/jp0526187] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photoluminescence (PL) intermittency characteristics are examined for single quantum dots (QDs) in a CdSe QD sample synthesized at a slow rate at 75 degrees C. Although the PL quantum efficiency was relatively low ( approximately 0.25), we noticed that the PL intensity of single CdSe QDs fluctuated on a subsecond time scale with short-lived "on" and "off" states. The subsecond PL intensity fluctuations of CdSe QDs are different from "on" and "off" PL blinking generally observed for QDs fluctuating on a millisecond to minute time scale. We characterized single QDs by identifying polarized excitations, topographic imaging using atomic force microscopy (AFM), and transmission electron microscopy (TEM). From analysis of the PL intensity trajectories from >100 single CdSe QDs, the average intermittency time was 213 ms. From the PL quantum efficiency, slow growth of QDs, intensity trajectory analyses, and previous reports relating surface trap states and PL properties of QDs, we attribute the subsecond PL intensity fluctuations of single CdSe QDs and short-lived "on" and "off" states to a high-density distribution of homogeneous surface trap states.
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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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277
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Jeong S, Achermann M, Nanda J, Ivanov S, Klimov VI, Hollingsworth JA. Effect of the Thiol−Thiolate Equilibrium on the Photophysical Properties of Aqueous CdSe/ZnS Nanocrystal Quantum Dots. J Am Chem Soc 2005; 127:10126-7. [PMID: 16028897 DOI: 10.1021/ja042591p] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We study the effect of thiols on the emission efficiency of aqueous CdSe/ZnS core/shell nanocrystal quantum dots (NQDs). We observe that the impact of thiol addition on emission quantum yields (QYs) is time-, concentration-, and pH-dependent. Further, we use a combination of time-resolved spectroscopic methods to determine the mechanism by which thiol addition can cause either increases or decreases in QYs. Specifically, through transient absorption measurements, we show that thiol addition can improve passivation of electron traps, increasing QYs at low thiol concentrations. Further, using nanosecond photoluminescence (PL), we observe that at higher thiol concentrations, hole traps are introduced that reduce PL QYs. Last, through a combination of pH-dependence and control studies (e.g., addition of 2-methyl thioethanol to an aqueous NQD solution and addition of dodecanethiol to a hexane NQD solution), we demonstrate that it is the ability of thiols in aqueous solution to generate thiolate that is the source of both favorable and adverse QY changes. Our results contribute to the understanding of the role of surface ligands, which is critical to the design of stable, high-quantum-yield, nonblinking NQDs.
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Affiliation(s)
- Sohee Jeong
- C-PCS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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278
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Medintz IL, Uyeda HT, Goldman ER, Mattoussi H. Quantum dot bioconjugates for imaging, labelling and sensing. NATURE MATERIALS 2005; 4:435-46. [PMID: 15928695 DOI: 10.1038/nmat1390] [Citation(s) in RCA: 3739] [Impact Index Per Article: 196.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
One of the fastest moving and most exciting interfaces of nanotechnology is the use of quantum dots (QDs) in biology. The unique optical properties of QDs make them appealing as in vivo and in vitro fluorophores in a variety of biological investigations, in which traditional fluorescent labels based on organic molecules fall short of providing long-term stability and simultaneous detection of multiple signals. The ability to make QDs water soluble and target them to specific biomolecules has led to promising applications in cellular labelling, deep-tissue imaging, assay labelling and as efficient fluorescence resonance energy transfer donors. Despite recent progress, much work still needs to be done to achieve reproducible and robust surface functionalization and develop flexible bioconjugation techniques. In this review, we look at current methods for preparing QD bioconjugates as well as presenting an overview of applications. The potential of QDs in biology has just begun to be realized and new avenues will arise as our ability to manipulate these materials improves.
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Affiliation(s)
- Igor L Medintz
- Center for Bio/Molecular Science and Engineering, Code 6900, US Naval Research Laboratory, Washington, DC 20375, USA.
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279
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Dyadyusha L, Yin H, Jaiswal S, Brown T, Baumberg JJ, Booy FP, Melvin T. Quenching of CdSe quantum dot emission, a new approach for biosensing. Chem Commun (Camb) 2005:3201-3. [PMID: 15968371 DOI: 10.1039/b500664c] [Citation(s) in RCA: 180] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The emission of CdSe quantum dots linked to the 5'-end of a DNA sequence is efficiently quenched by hybridisation with a complementary DNA strand with a gold nanoparticle attached at the 3'-end; contact of the quantum dot and gold nanoparticle occurs.
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Affiliation(s)
- L Dyadyusha
- School of Electronics and Computer Science, University of Southampton, Highfield, UK
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280
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Tinnefeld P, Sauer M. Branching Out of Single‐Molecule Fluorescence Spectroscopy: Challenges for Chemistry and Influence on Biology. Angew Chem Int Ed Engl 2005; 44:2642-2671. [PMID: 15849689 DOI: 10.1002/anie.200300647] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the last decade emerging single-molecule fluorescence-spectroscopy tools have been developed and adapted to analyze individual molecules under various conditions. Single-molecule-sensitive optical techniques are now well established and help to increase our understanding of complex problems in different disciplines ranging from materials science to cell biology. Previous dreams, such as the monitoring of the motility and structural changes of single motor proteins in living cells or the detection of single-copy genes and the determination of their distance from polymerase molecules in transcription factories in the nucleus of a living cell, no longer constitute unsolvable problems. In this Review we demonstrate that single-molecule fluorescence spectroscopy has become an independent discipline capable of solving problems in molecular biology. We outline the challenges and future prospects for optical single-molecule techniques which can be used in combination with smart labeling strategies to yield quantitative three-dimensional information about the dynamic organization of living cells.
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Affiliation(s)
- Philip Tinnefeld
- Applied Laserphysics und Laserspectroscopy, Faculty of Physics, University of Bielefeld, Universitätsstrasse 25, 33615 Bielefeld, Germany, Fax: (+49) 521-106-2958
| | - Markus Sauer
- Applied Laserphysics und Laserspectroscopy, Faculty of Physics, University of Bielefeld, Universitätsstrasse 25, 33615 Bielefeld, Germany, Fax: (+49) 521-106-2958
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281
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Tinnefeld P, Sauer M. Neue Wege in der Einzelmolekül-Fluoreszenzspektroskopie: Herausforderungen für die Chemie und Einfluss auf die Biologie. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200300647] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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282
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Abstract
Fluorescent semiconductor nanocrystals, known as quantum dots (QDs), have several unique optical and chemical features. These features make them desirable fluorescent tags for cell and developmental biological applications that require long-term, multi-target and highly sensitive imaging. The improved synthesis of water-stable QDs, the development of approaches to label cells efficiently with QDs, and improvements in conjugating QDs to specific biomolecules have triggered the recent explosion in their use in biological imaging. Although there have been many successes in using QDs for biological applications, limitations remain that must be overcome before these powerful tools can be used routinely by biologists.
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Affiliation(s)
- Jyoti K Jaiswal
- The Rockefeller University, Box 304, 1230 York Avenue, New York, NY 1002, USA
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283
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Doose S, Tsay JM, Pinaud F, Weiss S. Comparison of Photophysical and Colloidal Properties of Biocompatible Semiconductor Nanocrystals Using Fluorescence Correlation Spectroscopy. Anal Chem 2005; 77:2235-42. [PMID: 15801758 DOI: 10.1021/ac050035n] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A number of different surface chemistries have been developed in recent years to render semiconductor nanocrystals (NCs) stable in water and biocompatible. However, most of these surface modifications affect NCs' photophysical properties, calling for a method to simultaneously monitor colloidal and fluorescence properties. Fluorescence correlation spectroscopy (FCS) combined with ensemble spectroscopic methods and Monte Carlo simulations were used to interpret and derive photophysical as well as colloidal properties of four different NC surface treatments. Using a novel FCS scheme with alternating laser excitation at two different intensities, we first ruled out influences from optical gradient forces (optical trapping). We then compared concentration of emitting particles, brightness per particle, saturation intensity, blinking (intermittency), hydrodynamic radius, and propensity for aggregation of the different bioconjugated NCs. This approach was successfully applied during the development and optimization of peptide-coated NCs.
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Affiliation(s)
- Sören Doose
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California 90095, USA.
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284
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Michalet X, Pinaud FF, Bentolila LA, Tsay JM, Doose S, Li JJ, Sundaresan G, Wu AM, Gambhir SS, Weiss S. Quantum dots for live cells, in vivo imaging, and diagnostics. Science 2005; 307:538-44. [PMID: 15681376 PMCID: PMC1201471 DOI: 10.1126/science.1104274] [Citation(s) in RCA: 4765] [Impact Index Per Article: 250.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Research on fluorescent semiconductor nanocrystals (also known as quantum dots or qdots) has evolved over the past two decades from electronic materials science to biological applications. We review current approaches to the synthesis, solubilization, and functionalization of qdots and their applications to cell and animal biology. Recent examples of their experimental use include the observation of diffusion of individual glycine receptors in living neurons and the identification of lymph nodes in live animals by near-infrared emission during surgery. The new generations of qdots have far-reaching potential for the study of intracellular processes at the single-molecule level, high-resolution cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
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Affiliation(s)
- X. Michalet
- Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - F. F. Pinaud
- Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - L. A. Bentolila
- Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - J. M. Tsay
- Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - S. Doose
- Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - J. J. Li
- Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
| | - G. Sundaresan
- Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology
| | - A. M. Wu
- Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology
| | - S. S. Gambhir
- Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology
- Department of Radiology and Bio-X Program, Molecular Imaging Program at Stanford (MIPS), Stanford University School of Medicine, Stanford, CA 94305, USA
| | - S. Weiss
- Department of Chemistry and Biochemistry, University of California, 607 Charles E. Young Drive East, Los Angeles, CA 90095, USA
- Department of Physiology, David Geffen School of Medicine, University of California, 700 Westwood Plaza, Los Angeles, CA 90095, USA
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285
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HOHNG SUNGCHUL, HA TAEKJIP. Single-Molecule FRET. Mol Imaging 2005. [DOI: 10.1016/b978-019517720-6.50018-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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286
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Nakashima T, Kawai T. Quantum dots–ionic liquid hybrids: efficient extraction of cationic CdTe nanocrystals into an ionic liquid. Chem Commun (Camb) 2005:1643-5. [PMID: 15770287 DOI: 10.1039/b418001a] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Water soluble CdTe nanocrystals covered with cationic thiol derivatives are efficiently transferred into a hydrophobic ionic liquid, in which they show enhanced photoluminescence.
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Affiliation(s)
- Takuya Nakashima
- Research and Education Center for Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
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287
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Nann T. Phase-transfer of CdSe@ZnS quantum dots using amphiphilic hyperbranched polyethylenimine. Chem Commun (Camb) 2005:1735-6. [PMID: 15791315 DOI: 10.1039/b414807j] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new, straightforward method for the phase-transfer of CdSe@ZnS quantum dots from non-polar solvents into water and short-chained alcohols using amphiphilic hyperbranched polyethylenimine of different molar weights is suggested and the experimental procedure is discussed as well as the chemical properties of the resulting polymer-derivatised nanocrystals.
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Affiliation(s)
- Thomas Nann
- Freiburg Materials Research Center (FMF), Stefan-Meier-Str. 21, D-79104 Freiburg, Germany.
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288
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Michalet X, Pinaud FF, Bentolila LA, Tsay JM, Doose S, Li JJ, Iyer G, Weiss S. Peptide-coated semiconductor nanocrystals for biomedical applications. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2005; 5704:10.1117/12.589498. [PMID: 29176922 PMCID: PMC5701801 DOI: 10.1117/12.589498] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
We have developed a new functionalization approach for semiconductor nanocrystals based on a single-step exchange of surface ligands with custom-designed peptides. This peptide-coating technique yield small, monodisperse and very stable water-soluble NCs that remain bright and photostable. We have used this approach on several types of core and core-shell NCs in the visible and near-infrared spectrum range and used fluorescence correlation spectroscopy for rapid assessment of the colloidal and photophysical properties of the resulting particles. This peptide coating strategy has several advantages: it yields probes that are immediately biocompatible; it is amenable to improvements of the different properties (solubilization, functionalization, etc) via rational design, parallel synthesis, or molecular evolution; it permits the combination of several functions on individual NCs. These functionalized NCs have been used for diverse biomedical applications. Two are discussed here: single-particle tracking of membrane receptor in live cells and combined fluorescence and PET imaging of targeted delivery in live animals.
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Affiliation(s)
- X Michalet
- Dpt of Chemistry & Biochemistry, UCLA, 607 Charles E. Young Drive East, Los Angeles, CA 90095
| | - F F Pinaud
- Dpt of Chemistry & Biochemistry, UCLA, 607 Charles E. Young Drive East, Los Angeles, CA 90095
| | - L A Bentolila
- Dpt of Chemistry & Biochemistry, UCLA, 607 Charles E. Young Drive East, Los Angeles, CA 90095
| | - J M Tsay
- Dpt of Chemistry & Biochemistry, UCLA, 607 Charles E. Young Drive East, Los Angeles, CA 90095
| | - S Doose
- Applied Laserphysics & Laserspectroscopy, University of Bielefeld 33615 Bielefeld, Germany
| | - J J Li
- Dpt of Chemistry & Biochemistry, UCLA, 607 Charles E. Young Drive East, Los Angeles, CA 90095
| | - G Iyer
- Dpt of Chemistry & Biochemistry, UCLA, 607 Charles E. Young Drive East, Los Angeles, CA 90095
| | - S Weiss
- Dpt of Chemistry & Biochemistry, UCLA, 607 Charles E. Young Drive East, Los Angeles, CA 90095
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289
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Eggeling C. Nanotechnology and Single Molecules. Chemphyschem 2004; 5:1483-7. [PMID: 15535545 DOI: 10.1002/cphc.200400290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Christian Eggeling
- Max-Planck-Institute for Biophysical Chemistry, Department of NanoBiophotonics, Göttingen, Germany.
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290
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291
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van Dijk MA, Kapitein LC, van Mameren J, Schmidt CF, Peterman EJG. Combining Optical Trapping and Single-Molecule Fluorescence Spectroscopy: Enhanced Photobleaching of Fluorophores. J Phys Chem B 2004; 108:6479-84. [DOI: 10.1021/jp049805+] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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292
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Ha T. Structural Dynamics and Processing of Nucleic Acids Revealed by Single-Molecule Spectroscopy. Biochemistry 2004; 43:4055-63. [PMID: 15065847 DOI: 10.1021/bi049973s] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Single-molecule fluorescence spectroscopy is a powerful method to observe real time movements of individual biological molecules while they are functioning without the need for synchronization. Dynamic characteristics of nucleic acids can now be easily and reliably studied, and new applications are emerging in which their recognition and processing by proteins and enzymes are being understood with unprecedented detail. The most recent examples are discussed, including the hairpin ribozyme, Holliday junction, G-quadruplex, Rep helicase, reverse transcriptase, and combination with mechanical manipulation.
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Affiliation(s)
- Taekjip Ha
- Department of Physics and Center for Biophysics and Computational Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801, USA.
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