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Abstract
We introduce mechanically reconfigurable photonic metamaterials (RPMs) as a flexible platform for realizing metamaterial devices with reversible and large-range tunable characteristics in the optical part of the spectrum. Here we illustrate this concept for a temperature-driven RPM exhibiting reversible relative transmission changes of up to 50%.
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Affiliation(s)
- J Y Ou
- Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, SO17 1BJ, United Kingdom.
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Hunt RC, Geetha S, Allen CE, Hershko K, Fathke R, Kong PL, Plum E, Struble EB, Soejima K, Friedman S, Garfield S, Balaji S, Kimchi-Sarfaty C. Detection of a secreted metalloprotease within the nuclei of liver cells. Mol Biosyst 2011; 7:2012-8. [PMID: 21479334 DOI: 10.1039/c0mb00303d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ADAMTS13 is a secreted zinc metalloprotease expressed by various cell types. Here, we investigate its cellular pathway in endogenously expressing liver cell lines and after transient transfection with ADAMTS13. Besides compartmentalizations of the cellular secretory system, we detected an appreciable level of endogenous ADAMTS13 within the nucleus. A positively charged amino acid cluster (R-Q-R-Q-R-Q-R-R) present in the ADAMTS13 propeptide may act as a nuclear localization signal (NLS). Fusing this NLS-containing region to eGFP greatly potentiated its nuclear localization. Bioinformatics analysis suggests that the ADAMTS13 CUB-2 domain has a double-stranded beta helix (DSBH) structural architecture characteristic of various protein-protein interaction modules like nucleoplasmins, class I collagenase, tumor necrosis factor ligand superfamily, supernatant protein factor (SPF) and the B1 domain of neuropilin-2. Based on this contextual evidence and that largely conserved polar residues could be mapped on to a template CUB domain homolog, we hypothesize that a region in the ADAMTS13 CUB-2 domain with conserved polar residues might be involved in protein-protein interaction within the nucleus.
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Affiliation(s)
- Ryan C Hunt
- Laboratory of Hemostasis, Division of Hematology, Center for Biologic, Food and Drug Administration, Bethesda, Maryland 20892, USA
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Tanaka K, Plum E, Ou JY, Uchino T, Zheludev NI. Multifold enhancement of quantum dot luminescence in plasmonic metamaterials. Phys Rev Lett 2010; 105:227403. [PMID: 21231422 DOI: 10.1103/physrevlett.105.227403] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Indexed: 05/15/2023]
Abstract
We report that hybridizing semiconductor quantum dots with plasmonic metamaterial leads to a multifold intensity increase and narrowing of their photoluminescence spectrum. The luminescence enhancement is a clear manifestation of the cavity quantum electrodynamics Purcell effect and can be controlled by the metamaterial's design. This observation is an essential step towards understanding loss compensation in plasmonic metamaterials with gain media and for developing metamaterial-enhanced gain media.
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Affiliation(s)
- K Tanaka
- Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Southampton SO17 1BJ, United Kingdom.
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Fedotov VA, Papasimakis N, Plum E, Bitzer A, Walther M, Kuo P, Tsai DP, Zheludev NI. Spectral collapse in ensembles of metamolecules. Phys Rev Lett 2010; 104:223901. [PMID: 20867169 DOI: 10.1103/physrevlett.104.223901] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 04/20/2010] [Indexed: 05/27/2023]
Abstract
We report on the first direct experimental demonstration of a collective phenomenon in metamaterials: spectral line collapse with an increasing number of unit cell resonators (metamolecules). This effect, which is crucial for achieving a lasing spaser, a coherent source of optical radiation fuelled by coherent plasmonic oscillations in metamaterials, is linked to the suppression of radiation losses in periodic arrays. We experimentally demonstrate spectral line collapse at microwave, terahertz and optical frequencies.
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Affiliation(s)
- V A Fedotov
- Optoelectronics Research Centre, University of Southampton, SO17 1BJ, United Kingdom.
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Geetha S, Allen CE, Hunt RC, Plum E, Garfield S, Friedman SL, Soejima K, Sauna ZE, Kimchi-Sarfaty C. Detection of intracellular ADAMTS13, a secreted zinc-metalloprotease, via flow cytometry. Cytometry A 2009; 75:675-81. [PMID: 19526483 DOI: 10.1002/cyto.a.20748] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
ADAMTS13 is a secreted metalloprotease that cleaves von Willebrand Factor multimers in order to maintain proper homeostasis. A severe deficiency in ADAMTS13 triggers a disorder known as thrombotic thrombocytopenic purpura. At present, ADAMTS13 expression levels are determined by immunoblotting. We established a flow cytometry methodology to detect intracellular ADAMTS13 in liver and kidney cells using a polyclonal antibody, BL154G, and several monoclonal antibodies previously used to detect ADAMTS13 by immunoblotting. The results were validated using confocal microscopy, immunoblotting, and an activity assay (FRETS-VWF73). We show that labeling ADAMTS13 with specific antibodies and detection by flow cytometry yields results that are comparable with previously established methods for ADAMTS13 detection. Specifically, we compared the endogenous expression levels of ADAMTS13 in various liver cell lines using flow cytometry and obtained results that parallel immunoblot analysis. Knockdown of ADAMTS13 expression via targeted siRNA resulted in significantly reduced median signal, displaying the sensitivity of this detection method. A further analysis of reliability and specificity was achieved through plasmid DNA and transfection reagent dose response studies. The flow cytometry method described here is useful in determining the expression of both endogenous and recombinant forms of intracellular ADAMTS13. Flow cytometry is a convenient, efficient, and cost-effective way to measure the expression levels of ADAMTS13.
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Affiliation(s)
- S Geetha
- Division of Hematology, Laboratory of Hemostasis, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA
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Sauna ZE, Okunji C, Hunt RC, Gupta T, Allen CE, Plum E, Blaisdell A, Grigoryan V, S G, Fathke R, Soejima K, Kimchi-Sarfaty C. Characterization of conformation-sensitive antibodies to ADAMTS13, the von Willebrand cleavage protease. PLoS One 2009; 4:e6506. [PMID: 19654870 PMCID: PMC2716513 DOI: 10.1371/journal.pone.0006506] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 06/27/2009] [Indexed: 12/17/2022] Open
Abstract
Background The zinc metalloprotease ADAMTS13 is a multidomain protein that cleaves von Willebrand Factor (VWF) and is implicated in Thrombotic Thrombocytopenic Purpura (TTP) pathogenesis. Understanding the mechanism of this protein is an important goal. Conformation sensitive antibodies have been used to monitor protein conformation and to decipher the molecular mechanism of proteins as well as to distinguish functional and non-functional mutants. Methodology/Principal Findings We have characterized several antibodies against ADAMTS13, both monoclonal and polyclonal. We have used flow cytometry to estimate the binding of these antibodies to ADAMTS13 and demonstrate that antibodies raised against the TSP and disintegrin domains detect conformation changes in the ADAMTS13. Thus for example, increased binding of these antibodies was detected in the presence of the substrate (VWF), mainly at 37°C and not at 4°C. These antibodies could also detect differences between wild-type ADAMTS13 and the catalytically deficient mutant (P475S). The flow cytometry approach also allows us to estimate the reactivity of the antibody as well as its apparent affinity. Conclusions/Significance Our results suggest that these antibodies may serve as useful reagents to distinguish functional and non-functional ADAMTS13 and analyze conformational transitions to understand the catalytic mechanism.
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Affiliation(s)
- Zuben E. Sauna
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
- * E-mail: (ZES); (CKS)
| | - Chinyere Okunji
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Ryan C. Hunt
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Tanvi Gupta
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Courtni E. Allen
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Elizabeth Plum
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Adam Blaisdell
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Vahan Grigoryan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Geetha S
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Robert Fathke
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Kenji Soejima
- First Research Department, the Chemo-Sero-Therapeutic Research Institute, Kumamoto, Japan
| | - Chava Kimchi-Sarfaty
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
- * E-mail: (ZES); (CKS)
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Plum E, Fedotov VA, Kuo P, Tsai DP, Zheludev NI. Towards the lasing spaser: controlling metamaterial optical response with semiconductor quantum dots. Opt Express 2009; 17:8548-8551. [PMID: 19434188 DOI: 10.1364/oe.17.008548] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report the first experimental demonstration of compensating Joule losses in metallic photonic metamaterial using optically pumped PbS semiconductor quantum dots.
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Affiliation(s)
- E Plum
- Optoelectronics Research Centre, University of Southampton, Southampton, United Kingdom.
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Plum E, Liu XX, Fedotov VA, Chen Y, Tsai DP, Zheludev NI. Metamaterials: optical activity without chirality. Phys Rev Lett 2009; 102:113902. [PMID: 19392202 DOI: 10.1103/physrevlett.102.113902] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 01/22/2009] [Indexed: 05/10/2023]
Abstract
We report that the classical phenomenon of optical activity, which is traditionally associated with chirality (helicity) of organic molecules, proteins, and inorganic structures, can be observed in artificial planar media which exhibit neither 3D nor 2D chirality. We observe the effect in the microwave and optical parts of the spectrum at oblique incidence to regular arrays of nonchiral subwavelength metamolecules in the form of strong circular dichroism and birefringence indistinguishable from those of chiral three-dimensional media.
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Affiliation(s)
- E Plum
- Optoelectronics Research Centre, University of Southampton, SO17 1BJ, United Kingdom
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