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Quantum and carbon dots conjugated molecularly imprinted polymers as advanced nanomaterials for selective recognition of analytes in environmental, food and biomedical applications. Trends Analyt Chem 2021. [DOI: 10.1016/j.trac.2021.116306] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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2
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Kumar Singh A, Burkhow SJ, Wijesooriya C, Boote BW, Petrich JW, Smith EA. Inorganic Semiconductor Quantum Dots as a Saturated Excitation (SAX) Probe for Sub‐Diffraction Imaging. CHEMPHOTOCHEM 2020. [DOI: 10.1002/cptc.202000195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Avinash Kumar Singh
- Chemical and Biological Science Division The Ames laboratory US DOE 311 Iowa State University Ames IA 50011 USA
| | - Sadie J. Burkhow
- Chemical and Biological Science Division The Ames laboratory US DOE 311 Iowa State University Ames IA 50011 USA
- Department of Chemistry Iowa State University Ames IA 50011 USA
| | | | - Brett W. Boote
- Chemical and Biological Science Division The Ames laboratory US DOE 311 Iowa State University Ames IA 50011 USA
- Department of Chemistry Iowa State University Ames IA 50011 USA
| | - Jacob W. Petrich
- Chemical and Biological Science Division The Ames laboratory US DOE 311 Iowa State University Ames IA 50011 USA
- Department of Chemistry Iowa State University Ames IA 50011 USA
| | - Emily A. Smith
- Chemical and Biological Science Division The Ames laboratory US DOE 311 Iowa State University Ames IA 50011 USA
- Department of Chemistry Iowa State University Ames IA 50011 USA
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3
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Kim J, Lee SH, Im SH, Hong KH. Phase Selection of Cesium Lead Triiodides through Surface Ligand Engineering. J Phys Chem Lett 2020; 11:4232-4238. [PMID: 32374609 DOI: 10.1021/acs.jpclett.0c00499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The cesium lead triiodide (CsPbI3) perovskite is a promising candidate for stable light absorbers and red-light-emitting sources due to its outstanding stability. Phase engineering is the most important approach for the commercialization of CsPbI3 because the optically inactive nonperovskite structure is more stable than three-dimensional (3-D) perovskite lattices at ambient temperature. This study presents an in-depth evaluation to find the optimum surface ligand and to reveal the mechanism of phase stabilization by surface ligands. Thermodynamic evaluations combined with density functional theory calculations indicate the criteria for forming stable 3-D CsPbI3 perovskites under surface and volume free energy competition between perovskite and nonperovskite phases. Comparative calculations for ammonium, alcohol, and thiol groups show that ammonium groups enhance the phase stability of 3-D perovskites the most. In addition, ammonium-passivated CsPbI3 is relatively robust against defect formation and H2O adsorption.
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Affiliation(s)
- Jongseob Kim
- Samsung Advanced Institute of Technology, 130, Samsung-ro, Yeongtong-gu, Suwon 16678, Korea
| | - Sung-Hoon Lee
- Department of Applied Physics and Institute of Natural Sciences, Kyung Hee University, Yongin 17104, Korea
| | - Sang Hyuk Im
- Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea
| | - Ki-Ha Hong
- Department of Materials Science and Engineering, Hanbat National University, 125 Dongseo-daero, Yuseong-Gu, Daejeon 34158, Korea
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Li Q, Liu X, Wang X, Qiu S, Byambasuren K, Dang L, Wang Z. Antiproliferative Ability and Fluorescence Tracking of α-Linolenic Acid-Loaded Microemulsion as Label-Free Delivery Carriers in MDA-MB-231 Cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:11518-11526. [PMID: 31513385 DOI: 10.1021/acs.jafc.9b04972] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this work, the effects of α-linolenic acid (ALA) loaded in oil-in-water (O/W) and water-in-oil-in-water (W/O/W) microemulsions on cell viability, lactic dehydrogenase (LDH) viability, and reactive oxygen species (ROS) levels were examined using Cell Counting Kit-8 (CCK-8), an LDH assay kit, and a fluorescence microscope, respectively. The CCK-8 assay demonstrated that ALA inhibited MDA-MB-231 human breast cancer cell proliferation in a dose-dependent manner. Further, the results of LDH activity and ROS levels revealed that ALA-induced cancer cell damage was closely related to oxidative stress. Under the irradiation of ultraviolet light, the microemulsion without any added fluorescent dye would emit bright blue fluorescence, and the fluorescent images of the cells treated with ALA-loaded O/W and W/O/W microemulsions at different incubation times were taken, which exhibited long-term photostability and biocompatibility. In addition, the fluorescence mechanism of the microemulsion was explained by immobilizing surfactant molecules with aggregation-induced emission (AIE) properties at the water-oil interface through the microemulsion with a self-assembled structure. These findings showed the potential application of O/W and W/O/W microemulsions as the label-free delivery carriers in long-term imaging of living cells and real-time release monitoring of nutrients.
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Affiliation(s)
- Qing Li
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , China
| | - Xiaoxue Liu
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , China
| | - Xueping Wang
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , China
| | - Shuang Qiu
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , China
| | | | - Leping Dang
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , China
| | - Zhanzhong Wang
- School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , China
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5
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Thomas EM, Ghimire S, Kohara R, Anil AN, Yuyama KI, Takano Y, Thomas KG, Biju V. Blinking Suppression in Highly Excited CdSe/ZnS Quantum Dots by Electron Transfer under Large Positive Gibbs (Free) Energy Change. ACS NANO 2018; 12:9060-9069. [PMID: 30103604 DOI: 10.1021/acsnano.8b03010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Semiconductor quantum dots with stable photoluminescence are necessary for next generation optoelectronic and photovoltaic devices. Photoluminescence intensity fluctuations of cadmium and lead chalcogenide quantum dots have been extensively investigated since the first observation of blinking in CdSe nanocrystals in 1996. In a quantum dot, blinking originates from stochastic photocharging, nonradiative Auger recombination, and delayed neutralization. So far, blinking is suppressed by defect passivation, electron transfer, and shell preparation, but without any deep insight into free energy change of electron transfer. We report real-time detection of significant blinking suppression for CdSe/ZnS quantum dots exposed to N, N-dimethylaniline, which is accompanied by a considerable increase in the time-averaged photoluminescence intensity of quantum dots. Although the Gibbs (free) energy change (Δ Get = +2.24 eV), which is estimated electrochemically and from density functional theory calculations, is unfavorable for electron transfer from N, N-dimethylaniline to a quantum dot in the minimally excited (band-edge) state, electron transfer is obvious when a quantum dot is highly excited. Nonetheless, Δ Get crosses from the positive to negative scale as the solvent dielectric constant exceeds 5, favoring electron transfer from N, N-dimethylaniline to a quantum dot excited to the band-edge state. Based on single-molecule photoluminescence and ensemble electron transfer studies, we assign blinking suppression to the transfer of an electron from N, N-dimethylaniline to the hot hole state of a quantum dot. In addition to blinking suppression by electron transfer, complete removal of blinking is limited by short-living OFF states induced by the negative trion.
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Affiliation(s)
- Elizabeth Mariam Thomas
- Research Institute for Electronic Science , Hokkaido University , Sapporo , Hokkaido 001-0020 , Japan
- School of Chemistry , Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM) , Thiruvananthapuram 695551 , India
| | - Sushant Ghimire
- Research Institute for Electronic Science , Hokkaido University , Sapporo , Hokkaido 001-0020 , Japan
- Graduate School of Environmental Science , Hokkaido University , Sapporo , Hokkaido 060-0810 , Japan
| | - Reiko Kohara
- Research Institute for Electronic Science , Hokkaido University , Sapporo , Hokkaido 001-0020 , Japan
- Graduate School of Environmental Science , Hokkaido University , Sapporo , Hokkaido 060-0810 , Japan
| | - Ajith Nair Anil
- Research Institute for Electronic Science , Hokkaido University , Sapporo , Hokkaido 001-0020 , Japan
- Graduate School of Environmental Science , Hokkaido University , Sapporo , Hokkaido 060-0810 , Japan
| | - Ken-Ichi Yuyama
- Research Institute for Electronic Science , Hokkaido University , Sapporo , Hokkaido 001-0020 , Japan
- Graduate School of Environmental Science , Hokkaido University , Sapporo , Hokkaido 060-0810 , Japan
| | - Yuta Takano
- Research Institute for Electronic Science , Hokkaido University , Sapporo , Hokkaido 001-0020 , Japan
- Graduate School of Environmental Science , Hokkaido University , Sapporo , Hokkaido 060-0810 , Japan
| | - K George Thomas
- School of Chemistry , Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM) , Thiruvananthapuram 695551 , India
| | - Vasudevanpillai Biju
- Research Institute for Electronic Science , Hokkaido University , Sapporo , Hokkaido 001-0020 , Japan
- Graduate School of Environmental Science , Hokkaido University , Sapporo , Hokkaido 060-0810 , Japan
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Ashrafi K, Heaysman CL, Phillips GJ, Lloyd AW, Lewis AL. Towards Hypoxia-responsive Drug-eluting Embolization Beads. Int J Pharm 2017; 524:226-237. [PMID: 28373099 DOI: 10.1016/j.ijpharm.2017.03.084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 10/19/2022]
Abstract
Drug release from chemoembolization microspheres stimulated by the presence of a chemically reducing environment may provide benefits for targeting drug resistant and metastatic hypoxic tumours. A water-soluble disulfide-based bifunctional cross-linker bis(acryloyl)-(l)-cystine (BALC) was synthesised, characterised and incorporated into a modified poly(vinyl) alcohol (PVA) hydrogel beads at varying concentrations using reverse suspension polymerisation. The beads were characterised to confirm the amount of cross-linker within each formulation and its effects on the bead properties. Elemental and UV/visible spectroscopic analysis confirmed the incorporation of BALC within the beads and sizing studies showed that in the presence of a reducing agent, all bead formulations increased in mean diameter. The BALC beads could be loaded with doxorubicin hydrochloride and amounts in excess of 300mg of drug per mL of hydrated beads could be achieved but required conversion of the carboxylic acid groups of the BALC to their sodium carboxylate salt forms. Elution of doxorubicin from the beads demonstrated a controlled release via ionic exchange. Some formulations exhibited an increase in size and release of drug in the presence of a reducing agent, and therefore demonstrated the ability to respond to an in vitro reducing environment.
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Affiliation(s)
- Koorosh Ashrafi
- School of Pharmacy & Biomolecular Sciences, University of Brighton, Moulsecoomb, Brighton BN2 4GJ, United Kingdom; Biocompatibles UK Ltd, A BTG International Group Company, Lakeview, Riverside Way, Watchmoor Park, Camberley, GU15 3YL, United Kingdom
| | - Clare L Heaysman
- Biocompatibles UK Ltd, A BTG International Group Company, Lakeview, Riverside Way, Watchmoor Park, Camberley, GU15 3YL, United Kingdom
| | - Gary J Phillips
- School of Pharmacy & Biomolecular Sciences, University of Brighton, Moulsecoomb, Brighton BN2 4GJ, United Kingdom
| | - Andrew W Lloyd
- School of Pharmacy & Biomolecular Sciences, University of Brighton, Moulsecoomb, Brighton BN2 4GJ, United Kingdom
| | - Andrew L Lewis
- Biocompatibles UK Ltd, A BTG International Group Company, Lakeview, Riverside Way, Watchmoor Park, Camberley, GU15 3YL, United Kingdom.
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7
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Hu J, Wang ZY, Li CC, Zhang CY. Advances in single quantum dot-based nanosensors. Chem Commun (Camb) 2017; 53:13284-13295. [DOI: 10.1039/c7cc07752a] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We review the advances in single quantum dot-based nanosensors and their biomedical applications. We highlight their challenges and future direction.
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Affiliation(s)
- Juan Hu
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Zi-yue Wang
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Chen-chen Li
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Chun-yang Zhang
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
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8
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Reisch A, Klymchenko AS. Fluorescent Polymer Nanoparticles Based on Dyes: Seeking Brighter Tools for Bioimaging. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:1968-92. [PMID: 26901678 PMCID: PMC5405874 DOI: 10.1002/smll.201503396] [Citation(s) in RCA: 371] [Impact Index Per Article: 46.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 12/13/2015] [Indexed: 05/13/2023]
Abstract
Speed, resolution and sensitivity of today's fluorescence bioimaging can be drastically improved by fluorescent nanoparticles (NPs) that are many-fold brighter than organic dyes and fluorescent proteins. While the field is currently dominated by inorganic NPs, notably quantum dots (QDs), fluorescent polymer NPs encapsulating large quantities of dyes (dye-loaded NPs) have emerged recently as an attractive alternative. These new nanomaterials, inspired from the fields of polymeric drug delivery vehicles and advanced fluorophores, can combine superior brightness with biodegradability and low toxicity. Here, we describe the strategies for synthesis of dye-loaded polymer NPs by emulsion polymerization and assembly of pre-formed polymers. Superior brightness requires strong dye loading without aggregation-caused quenching (ACQ). Only recently several strategies of dye design were proposed to overcome ACQ in polymer NPs: aggregation induced emission (AIE), dye modification with bulky side groups and use of bulky hydrophobic counterions. The resulting NPs now surpass the brightness of QDs by ≈10-fold for a comparable size, and have started reaching the level of the brightest conjugated polymer NPs. Other properties, notably photostability, color, blinking, as well as particle size and surface chemistry are also systematically analyzed. Finally, major and emerging applications of dye-loaded NPs for in vitro and in vivo imaging are reviewed.
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Affiliation(s)
- Andreas Reisch
- Laboratoire de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74, Route du Rhin, 67401 ILLKIRCH Cedex, France
| | - Andrey S. Klymchenko
- Laboratoire de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74, Route du Rhin, 67401 ILLKIRCH Cedex, France
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9
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Zang H, Cristea M, Shen X, Liu M, Camino F, Cotlet M. Charge trapping and de-trapping in isolated CdSe/ZnS nanocrystals under an external electric field: indirect evidence for a permanent dipole moment. NANOSCALE 2015; 7:14897-14905. [PMID: 26293119 DOI: 10.1039/c5nr03714j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Single nanoparticle studies of charge trapping and de-trapping in core/shell CdSe/ZnS nanocrystals incorporated into an insulating matrix and subjected to an external electric field demonstrate the ability to reversibly modulate the exciton dynamics and photoluminescence blinking while providing indirect evidence for the existence of a permanent ground state dipole moment in such nanocrystals. A model assuming the presence of energetically deep charge traps physically aligned along the direction of the permanent dipole is proposed in order to explain the dynamics of nanocrystal blinking in the presence of a permanent dipole moment.
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Affiliation(s)
- Huidong Zang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA.
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10
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Yahiatène I, Aung HH, Wilson DW, Rutledge JC. Single-molecule quantification of lipotoxic expression of activating transcription factor 3. Phys Chem Chem Phys 2014; 16:21595-21601. [PMID: 25189785 PMCID: PMC4242794 DOI: 10.1039/c4cp03260h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Activating transcription factor 3 (ATF3) is a member of the mammalian activation transcription factor/cAMP, physiologically important in the regulation of pro- and anti-inflammatory target genes. We compared the induction of ATF3 protein as measured by Western blot analysis with single-molecule localization microscopy dSTORM to quantify the dynamics of accumulation of intranuclear ATF3 of triglyceride-rich (TGRL) lipolysis product-treated HAEC (Human Aortic Endothelial Cells). The ATF3 expression rate within the first three hours after treatment with TGRL lipolysis products is about 3500 h(-1). After three hours we detected 33,090 ± 3491 single-molecule localizations of ATF3. This was accompanied by significant structural changes in the F-actin network of the cells at ∼3-fold increased localization precision compared to widefield microscopy after treatment. Additionally, we discovered a cluster size of approximately 384 nanometers of ATF3 molecules. We show for the first time the time course of ATF3 accumulation in the nucleus undergoing lipotoxic injury. Furthermore, we demonstrate ATF3 accumulation associated with increased concentrations of TGRL lipolysis products occurs in large aggregates.
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Affiliation(s)
- Idir Yahiatène
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, CA 95616
- Biomolecular Photonics, Department of Physics, University of Bielefeld, 33615 Bielefeld, Germany
- Center for Biophotonics Science and Technology, UC Davis, 2700 Stockton Blvd, Sacramento, CA
| | - Hnin H. Aung
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, CA 95616
| | - Dennis W. Wilson
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616
| | - John C. Rutledge
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, CA 95616
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11
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Pedersen MN, Hedegård ED, Kongsted J. Basis set error estimation for DFT calculations of electronic g-tensors for transition metal complexes. J Comput Chem 2014; 35:1809-14. [PMID: 25060998 DOI: 10.1002/jcc.23688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 06/30/2014] [Accepted: 07/02/2014] [Indexed: 11/10/2022]
Abstract
We present a detailed study of the basis set dependence of electronic g-tensors for transition metal complexes calculated using Kohn-Sham density functional theory. Focus is on the use of locally dense basis set schemes where the metal is treated using either the same or a more flexible basis set than used for the ligand sphere. The performance of all basis set schemes is compared to the extrapolated complete basis set limit results. Furthermore, we test the performance of the aug-cc-pVTZ-J basis set developed for calculations of NMR spin-spin and electron paramagnetic resonance hyperfine coupling constants. Our results show that reasonable results can be obtain when using small basis sets for the ligand sphere, and very accurate results are obtained when an aug-cc-pVTZ basis set or similar is used for all atoms in the complex.
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Affiliation(s)
- Morten N Pedersen
- Department of Physics Chemistry Pharmacy, University of Southern Denmark, DK-5230, Odense M, Denmark
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12
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Shibu ES, Hamada M, Nakanishi S, Wakida SI, Biju V. Photoluminescence of CdSe and CdSe/ZnS quantum dots: Modifications for making the invisible visible at ensemble and single-molecule levels. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2013.10.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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13
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Yahiatène I, Hennig S, Huser T. Optical fluctuation microscopy based on calculating local entropy values. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.08.102] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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15
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Rombach-Riegraf V, Oswald P, Bienert R, Petersen J, Domingo M, Pardo J, Gräber P, Galvez E. Blinking effect and the use of quantum dots in single molecule spectroscopy. Biochem Biophys Res Commun 2013; 430:260-4. [DOI: 10.1016/j.bbrc.2012.10.140] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 10/31/2012] [Indexed: 10/27/2022]
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17
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Schwartz O, Tenne R, Levitt JM, Deutsch Z, Itzhakov S, Oron D. Colloidal quantum dots as saturable fluorophores. ACS NANO 2012; 6:8778-82. [PMID: 22992215 DOI: 10.1021/nn302551v] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Although colloidal quantum dots (QDs) exhibit excellent photostability under mild excitation, intense illumination makes their emission increasingly intermittent, eventually leading to photobleaching. We study fluorescence of two commonly used types of QDs under pulsed excitation with varying power and repetition rate. The photostability of QDs is found to improve dramatically at low repetition rates, allowing for prolonged optical saturation of QDs without apparent photodamage. This observation suggests that QD blinking is facilitated by absorption of light in a transient state with a microsecond decay time. Enhanced photostability of generic quantum dots under intense illumination opens up new prospects for fluorescence microscopy and spectroscopy.
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Affiliation(s)
- Osip Schwartz
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel 76100.
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18
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Xu Z, Cotlet M. Photoluminenscence blinking dynamics of colloidal quantum dots in the presence of controlled external electron traps. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:253-258. [PMID: 22180124 DOI: 10.1002/smll.201101643] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Indexed: 05/31/2023]
Abstract
The effect of the external charge trap on the photoluminescence blinking dynamics of individual colloidal quantum dots is investigated with a series of colloidal quantum dot-bridge-fullerene dimers with varying bridge lengths, where the fullerene moiety acts as a well-defined, well-positioned external charge trap. It is found that charge transfer followed by charge recombination is an important mechanism in determining the blinking behavior of quantum dots when the external trap is properly coupled with the excited state of the quantum dot, leading to a quasi-continuous distribution of 'on' states and an early fall-off from a power-law distribution for both 'on' and 'off' times associated with quantum dot photoluminescence blinking.
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Affiliation(s)
- Zhihua Xu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton New York 11973, USA
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19
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Shen FC, Yang J, Wang CF, Chen L, Chen S. Phase Transfer Mediated Self-Assembly of CdTe–Polymer Nanohybrids for Uniform Fluorescent Films. J Inorg Organomet Polym Mater 2011. [DOI: 10.1007/s10904-011-9492-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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20
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Lee AJ, Wang X, Carlson LJ, Smyder JA, Loesch B, Tu X, Zheng M, Krauss TD. Bright fluorescence from individual single-walled carbon nanotubes. NANO LETTERS 2011; 11:1636-40. [PMID: 21417364 DOI: 10.1021/nl200077t] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Single-walled carbon nanotubes (SWNTs) have unique photophysical properties but low fluorescence efficiency. We have found significant increases in the fluorescence efficiency of individual DNA-wrapped SWNTs upon addition of reducing agents, including dithiothreitol, Trolox, and β-mercaptoethanol. Brightening was reversible upon removal of the reducing molecules, suggesting that a transient reduction of defect sites on the SWNT sidewall causes the effect. These results imply that SWNTs are intrinsically bright emitters and that their poor emission arises from defective nanotubes.
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Affiliation(s)
- Andrea J Lee
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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21
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Ko HC, Yuan CT, Tang J. Probing and controlling fluorescence blinking of single semiconductor nanoparticles. NANO REVIEWS 2011; 2:NANO-2-5895. [PMID: 22110871 PMCID: PMC3215194 DOI: 10.3402/nano.v2i0.5895] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Revised: 01/11/2011] [Accepted: 01/12/2011] [Indexed: 11/14/2022]
Abstract
In this review we present an overview of the experimental and theoretical development on fluorescence intermittency (blinking) and the roles of electron transfer in semiconductor crystalline nanoparticles. Blinking is a very interesting phenomenon commonly observed in single molecule/particle experiments. Under continuous laser illumination, the fluorescence time trace of these single nanoparticles exhibit random light and dark periods. Since its first observation in the mid-1990s, this intriguing phenomenon has attracted wide attention among researchers from many disciplines. We will first present the historical background of the discovery and the observation of unusual inverse power-law dependence for the waiting time distributions of light and dark periods. Then, we will describe our theoretical modeling efforts to elucidate the causes for the power-law behavior, to probe the roles of electron transfer in blinking, and eventually to control blinking and to achieve complete suppression of the blinking, which is an annoying feature in many applications of quantum dots as light sources and fluorescence labels for biomedical imaging.
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Affiliation(s)
- Hsien-Chen Ko
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
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22
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Hamada M, Nakanishi S, Itoh T, Ishikawa M, Biju V. Blinking suppression in CdSe/ZnS single quantum dots by TiO2 nanoparticles. ACS NANO 2010; 4:4445-4454. [PMID: 20731430 DOI: 10.1021/nn100698u] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The photoluminescence of semiconductor quantum dots and fluorescence of single molecules intermittently turn ON and OFF, a phenomenon referred to as blinking. In quantum dots, blinking occurs as a result of intermittent Auger ionization, which results in the formation of positively charged quantum dots. Due to strong Coulombic interactions, successive photoactivation of a charged quantum dot results in nonradiative carrier recombination, inducing long-lived OFF states in the intensity trajectories. Blinking is an undesirable property with respect to applications of quantum dots toward single-molecule imaging and single-photon logic devices. Here we report significant blinking suppression for CdSe/ZnS single quantum dots in the presence of TiO(2) nanoparticles. In this work, we continuously recorded photoluminescence intensity trajectories of single quantum dots with and without TiO(2) nanoparticles. Interestingly, the intensity trajectory of a single quantum dot that was covalently tethered on a cover glass and dipped in water resulted in near-complete blinking suppression as soon as a TiO(2) nanoparticle solution was introduced. The blinking suppression was associated with a decrease in the photoluminescence intensity but without considerable changes in the photoluminescence lifetime, indicating that nonradiative carrier recombination in quantum dots was channeled into electron transfer to TiO(2) nanoparticles and back electron transfer to quantum dots. On the basis of these experiments and recent reports on photoinduced electron transfer from quantum dots to TiO(2) nanoparticles, we hypothesize that blinking of a quantum dot can be suppressed by increasing the rate of nonradiative regeneration of its neutral state by interfacing with a well-defined charge carrier trap such as an electron acceptor, which accepts an electron during Auger ionization and neutralizes the charged quantum dot by back electron transfer. Correlation between blinking suppression and electron transfer in a quantum dot-TiO(2) nanoparticle system may have important implications, for the preparation of nonblinking quantum dot for incessant and on-demand light emission, donor-acceptor systems for efficient solar energy harvesting, and hybrid semiconductor materials for quantum optical devices.
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Affiliation(s)
- Morihiko Hamada
- Nano-bioanalysis Group, Health Research Institute, National Institute of Advanced Industrial Science and Technology, 2217-14 Hayashi-Cho, Takamatsu, Kagawa 761-0396, Japan
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Early KT, Sudeep PK, Emrick T, Barnes MD. Polarization-driven stark shifts in quantum dot luminescence from single CdSe/oligo-PPV nanoparticles. NANO LETTERS 2010; 10:1754-1758. [PMID: 20392056 DOI: 10.1021/nl1001789] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We demonstrate polarization-induced spectral shifts and associated linearly polarized absorption and emission in single CdSe/oligo-(phenylene vinylene) (CdSe/OPV) nanoparticles. A mechanism for these observations is presented in which charge separation from photoexcited ligands results in a significant Stark distortion of the quantum dot electron/hole wavefunctions. This distortion results in an induced linear polarization and an associated red shift in band-edge photoluminescence. These studies suggest the use of single quantum dots as local charge mobility probes.
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Affiliation(s)
- K T Early
- Department of Chemistry and Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, USA
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Rosen S, Schwartz O, Oron D. Transient fluorescence of the off state in blinking CdSe/CdS/ZnS semiconductor nanocrystals is not governed by Auger recombination. PHYSICAL REVIEW LETTERS 2010; 104:157404. [PMID: 20482017 DOI: 10.1103/physrevlett.104.157404] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Indexed: 05/23/2023]
Abstract
The observed intermittent light emission from colloidal semiconductor nanocrystals has long been associated with Auger recombination assisted quenching. We test this view by observing transient emission dynamics of CdSe/CdS/ZnS semiconductor nanocrystals using time-resolved photon counting. The size and intensity dependence of the observed decay dynamics seem inconsistent with those expected from Auger processes. Rather, the data suggest that in the "off" state the quantum dot cycles in a three-step process: photoexcitation, rapid trapping, and subsequent slow nonradiative decay.
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Affiliation(s)
- Shamir Rosen
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel
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Antelman J, Wilking-Chang C, Weiss S, Michalet X. Nanometer distance measurements between multicolor quantum dots. NANO LETTERS 2009; 9:2199-205. [PMID: 19374434 PMCID: PMC2748936 DOI: 10.1021/nl901163k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Quantum dot dimers made of short double-stranded DNA molecules labeled with different color quantum dots at each end were imaged using multicolor stage-scanning confocal microscopy. This approach eliminates chromatic aberration and color registration issues usually encountered in other multicolor imaging techniques. We demonstrate nanometer accuracy in individual distance measurement by suppression of quantum dot blinking and thoroughly characterize the contribution of different effects to the variability observed between measurements. Our analysis opens the way to accurate structural studies of biomolecules and biomolecular complexes using multicolor quantum labeling.
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Affiliation(s)
| | | | | | - Xavier Michalet
- CORRESPONDING AUTHOR FOOTNOTE. Correspondence should be address to XM (, Ph: 310 794-6693, Fax: 310 267-4672)
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