201
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The effects of phenyl-bridged glucosyltriazolyl groups on the properties of water-soluble diarylethene derivatives. Tetrahedron 2014. [DOI: 10.1016/j.tet.2013.12.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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202
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Mayer M, Yang J. Engineered ion channels as emerging tools for chemical biology. Acc Chem Res 2013; 46:2998-3008. [PMID: 23932142 DOI: 10.1021/ar400129t] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Over the last 25 years, researchers have developed exogenously expressed, genetically engineered, semi-synthetic, and entirely synthetic ion channels. These structures have sufficient fidelity to serve as unique tools that can reveal information about living organisms. One of the most exciting success stories is optogenetics: the use of light-gated channels to trigger action potentials in specific neurons combined with studies of the response from networks of cells or entire live animals. Despite this breakthrough, the use of molecularly engineered ion channels for studies of biological systems is still in its infancy. Historically, researchers studied ion channels in the context of their own function in single cells or in multicellular signaling and regulation. Only recently have researchers considered ion channels and pore-forming peptides as responsive tools to report on the chemical and physical changes produced by other biochemical processes and reactions. This emerging class of molecular probes has a number of useful characteristics. For instance, these structures can greatly amplify the signal of chemical changes: the binding of one molecule to a ligand-gated ion channel can result in flux of millions of ions across a cell membrane. In addition, gating occurs on sub-microsecond time scales, resulting in fast response times. Moreover, the signal is complementary to existing techniques because the output is ionic current rather than fluorescence or radioactivity. And finally, ion channels are also localized at the membrane of cells where essential processes such as signaling and regulation take place. This Account highlights examples, mostly from our own work, of uses of ion channels and pore-forming peptides such as gramicidin in chemical biology. We discuss various strategies for preparing synthetically tailored ion channels that range from de novo designed synthetic molecules to genetically engineered or simply exogenously expressed or reconstituted wild-type channels. Next we consider aspects of experimental design by comparing various membrane environments or systems that make it possible to quantify the response of ion channels to biochemical processes of interest. We present applications of ion channels to answer questions in chemical biology, and propose potential future developments and applications of these single molecule probes. Finally we discuss the hurdles that impede the routine use of ion channel probes in biochemistry and cell biology laboratories and developments and strategies that could overcome these problems. Optogenetics has facilitated breakthroughs in neuroscience, and these results give a dramatic idea of what may lie ahead for designed ion channels as a functional class of molecular probes. If researchers can improve molecular engineering to increase ion channel versatility and can overcome the barriers to collaborating across disciplines, we conclude that these structures could have tremendous potential as novel tools for chemical biology studies.
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Affiliation(s)
- Michael Mayer
- Department of Chemical Engineering and Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, Michigan 48109-2110, United States
| | - Jerry Yang
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, California 92093-0358, United States
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203
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SzymaŃski W, Yilmaz D, Koçer A, Feringa BL. Bright ion channels and lipid bilayers. Acc Chem Res 2013; 46:2910-23. [PMID: 23597020 DOI: 10.1021/ar4000357] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
If we look at a simple organism such as a zebrafish under a microscope, we would see many cells working in harmony. If we zoomed in, we would observe each unit performing its own tasks in a special aqueous environment isolated from the other units by a lipid bilayer approximately 5 nm thick. These confined units are social: they communicate with one another by sensing and responding to the chemical changes in their environment through receptors and ion channels. These channels control the highly specific and selective passage of ions from one side of the cell to the other and are embedded in lipid bilayers. The movement of ions through ion channels supports excitation and electrical signaling in the nervous system. Ion channels have fascinated scientists not only because of their specificity and selectivity, but also for their functions, the serious consequences when they malfunction, and the other potential applications of these molecules. Light is a useful trigger to control and manipulate ion channels externally. With the many state-of-the-art optical technologies available, light offers a high degree of spatial and temporal control, millisecond precision, and noninvasive intervention and does not change the chemical environment of the system of interest. In this Account, we discuss research toward the dynamic control of lipid bilayer assembly and channel function, particularly the transport across the lipid bilayer-ion channel barrier of cells using light. We first summarize the manipulation of ion channel activity with light to modulate the channel's natural activity. Based on the type of photoswitch employed, we can achieve novel functionalities with these channels, and control neural activity. Then we discuss the recent developments in light-induced transport through lipid bilayers. We focus on three different approaches: the incorporation of photoswitchable copolymers into the lipids, the doping of the lipid bilayer with photosensitive amphiphiles and the preparation of the lipid bilayers solely from photoswitchable lipids. These examples reflect the versatility of what we can achieve by manipulating biological systems with light, from triggering the permeability of a specific area of a lipid bilayer to controlling the behavior of a whole organism.
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Affiliation(s)
- Wiktor SzymaŃski
- Center for Systems Chemistry, Stratingh Institute for Chemistry and ‡Groningen Biomolecular Sciences and Biotechnology Institute University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Duygu Yilmaz
- Center for Systems Chemistry, Stratingh Institute for Chemistry and ‡Groningen Biomolecular Sciences and Biotechnology Institute University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - ArmaĞan Koçer
- Center for Systems Chemistry, Stratingh Institute for Chemistry and ‡Groningen Biomolecular Sciences and Biotechnology Institute University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Ben L. Feringa
- Center for Systems Chemistry, Stratingh Institute for Chemistry and ‡Groningen Biomolecular Sciences and Biotechnology Institute University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
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204
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A stimuli-responsive nanopore based on a photoresponsive host-guest system. Sci Rep 2013; 3:1662. [PMID: 23588705 PMCID: PMC3627192 DOI: 10.1038/srep01662] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 03/27/2013] [Indexed: 12/17/2022] Open
Abstract
The open-close states of the ion channels in a living system are regulated by multiple stimuli such as ligand, pH, potential and light. Functionalizing natural channels by using synthetic chemistry would provide biological nanopores with novel properties and applications. Here we use para-sulfonato-calix[4]arene-based host-guest supramolecular system to develop artificial gating mechanisms aiming at regulating wild-type α-HL commanded by both ligand and light stimuli. Using the gating property of α-hemolysin, we studied the host-guest interactions between para-sulfonato-calix[4]arene and 4, 4'-dipyridinium-azobenzene at the single-molecule level. Subsequently, we have extended the application of this gating system to the real-time study of light-induced molecular shuttle based on para-sulfonato-calix[4]arene and 4, 4'-dipyridinium-azobenzene at the single-molecule level. These experiments provide a more efficient method to develop a general tool to analyze the individual motions of supramolecular systems by using commercially available α-HL nanopores.
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205
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Abstract
Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly desirable. Here we report a responsive, broad-spectrum, antibacterial agent that can be temporally activated with light, whereupon it auto-inactivates on the scale of hours. The use of such a 'smart' antibiotic might prevent the build-up of active antimicrobial material in the environment. Reversible optical control over active drug concentration enables us to obtain pharmacodynamic information. Precisely localized control of activity is achieved, allowing the growth of bacteria to be confined to defined patterns, which has potential for the development of treatments that avoid interference with the endogenous microbial population in other parts of the organism.
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206
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Abstract
In the past few years, spiropyran has emerged as the molecule-of-choice for the construction of novel dynamic materials. This unique molecular switch undergoes structural isomerisation in response to a variety of orthogonal stimuli, e.g. light, temperature, metal ions, redox potential, and mechanical stress. Incorporation of this switch onto macromolecular supports or inorganic scaffolds allows for the creation of robust dynamic materials. This review discusses the synthesis, switching conditions, and use of dynamic materials in which spiropyran has been attached to the surfaces of polymers, biomacromolecules, inorganic nanoparticles, as well as solid surfaces. The resulting materials show fascinating properties whereby the state of the switch intimately affects a multitude of useful properties of the support. The utility of the spiropyran switch will undoubtedly endow these materials with far-reaching applications in the near future.
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Affiliation(s)
- Rafal Klajn
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
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207
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Zhang WJ, Hong CY, Pan CY. Fabrication of Electrospinning Fibers from Spiropyran-Based Polymeric Nanowires and their Photochromic Properties. MACROMOL CHEM PHYS 2013. [DOI: 10.1002/macp.201300428] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Wen-Jian Zhang
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering; University of Science and Technology of China; Hefei Anhui 230026 P. R. China
| | - Chun-Yan Hong
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering; University of Science and Technology of China; Hefei Anhui 230026 P. R. China
| | - Cai-Yuan Pan
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering; University of Science and Technology of China; Hefei Anhui 230026 P. R. China
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208
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Oude Blenke E, Mastrobattista E, Schiffelers RM. Strategies for triggered drug release from tumor targeted liposomes. Expert Opin Drug Deliv 2013; 10:1399-410. [DOI: 10.1517/17425247.2013.805742] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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209
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Fukagawa M, Kawamura I, Ubukata T, Yokoyama Y. Enantioselective photochromism of diarylethenes in human serum albumin. Chemistry 2013; 19:9434-7. [PMID: 23784945 DOI: 10.1002/chem.201301459] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Mai Fukagawa
- Department of Advanced Materials Chemistry, Graduate School of Engineering, Yokohama National University, 79-5, Tokiwadai, Hodogaya, Yokohama 240-8501, Japan
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210
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Liang C, Jansen TLC. Simulation of Two-Dimensional Sum-Frequency Generation Response Functions: Application to Amide I in Proteins. J Phys Chem B 2013; 117:6937-45. [DOI: 10.1021/jp403111j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Chungwen Liang
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH - 4056 Basel,
Switzerland
| | - Thomas L. C. Jansen
- Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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211
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Shoji Y, Yagi A, Horiuchi M, Morimoto M, Irie M. Photochromic Diarylethene Derivatives Bearing Hydrophilic Substituents. Isr J Chem 2013. [DOI: 10.1002/ijch.201300018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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212
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Coumans RGE, Elemans JAAW, Rowan AE, Nolte RJM. Interlocked Porphyrin Switches. Chemistry 2013; 19:7758-70. [DOI: 10.1002/chem.201203983] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 04/03/2013] [Indexed: 11/12/2022]
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213
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Szymański W, Beierle JM, Kistemaker HAV, Velema WA, Feringa BL. Reversible Photocontrol of Biological Systems by the Incorporation of Molecular Photoswitches. Chem Rev 2013; 113:6114-78. [DOI: 10.1021/cr300179f] [Citation(s) in RCA: 847] [Impact Index Per Article: 77.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Wiktor Szymański
- Stratingh Institute
for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The
Netherlands
| | - John M. Beierle
- Stratingh Institute
for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The
Netherlands
| | - Hans A. V. Kistemaker
- Stratingh Institute
for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The
Netherlands
| | - Willem A. Velema
- Stratingh Institute
for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The
Netherlands
| | - Ben L. Feringa
- Stratingh Institute
for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The
Netherlands
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214
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Stimberg VC, Bomer JG, van Uitert I, van den Berg A, Le Gac S. High yield, reproducible and quasi-automated bilayer formation in a microfluidic format. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2013; 9:1076-1085. [PMID: 23139010 DOI: 10.1002/smll.201201821] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 08/27/2012] [Indexed: 05/28/2023]
Abstract
A microfluidic platform is reported for various experimentation schemes on cell membrane models and membrane proteins using a combination of electrical and optical measurements, including confocal microscopy. Bilayer lipid membranes (BLMs) are prepared in the device upon spontaneous and instantaneous thinning of the lipid solution in a 100-μm dry-etched aperture in a 12.5-μm thick Teflon foil. Using this quasi-automated approach, a remarkable 100% membrane formation yield is reached (including reflushing in 4% of the cases), and BLMs are stable for up to 36 h. Furthermore, the potential of this platform is demonstrated for (i) the in-depth characterization of BLMs comprising both synthetic and natural lipids (1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) and L-α-phosphatidylcholine (L-α-PC)/cholesterol, respectively) in terms of seal resistance, capacitance, surface area, specific capacitance, and membrane hydrophobic thickness; (ii) confocal microscopy imaging of phase separation in sphingomyelin/L-α-PC/cholesterol ternary membranes; (iii) electrical measurements of individual nanopores (α-hemolysin, gramicidin); and (iv) indirect assessment of the alteration of membrane properties upon exposure to chemical stimuli using the natural nanopore gramicidin as a sensor.
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Affiliation(s)
- Verena C Stimberg
- BIOS-Lab on a Chip Group, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
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215
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Minkin VI. Light-controlled molecular switches based on bistable spirocyclic organic and coordination compounds. RUSSIAN CHEMICAL REVIEWS 2013. [DOI: 10.1070/rc2013v082n01abeh004336] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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216
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Liang C, Louhivuori M, Marrink SJ, Jansen TLC, Knoester J. Vibrational Spectra of a Mechanosensitive Channel. J Phys Chem Lett 2013; 4:448-452. [PMID: 26281739 DOI: 10.1021/jz3019258] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the simulated vibrational spectra of a mechanosensitive membrane channel in different gating states. Our results show that while linear absorption is insensitive to structural differences, linear dichroism and sum-frequency generation spectroscopies are sensitive to the orientation of the transmembrane helices, which is changing during the opening process. Linear dichroism cannot distinguish an intermediate structure from the closed structure, but sum-frequency generation can. In addition, we find that two-dimensional infrared spectroscopy can be used to distinguish all three investigated gating states of the mechanosensitive membrane channel.
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Affiliation(s)
- Chungwen Liang
- †Center for Theoretical Physics and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Martti Louhivuori
- ‡Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Siewert J Marrink
- ‡Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Thomas L C Jansen
- †Center for Theoretical Physics and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Jasper Knoester
- †Center for Theoretical Physics and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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217
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Zhou H, Johnson JA. Photo-controlled Growth of Telechelic Polymers and End-linked Polymer Gels. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201207966] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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218
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Zhou H, Johnson JA. Photo-controlled Growth of Telechelic Polymers and End-linked Polymer Gels. Angew Chem Int Ed Engl 2013; 52:2235-8. [DOI: 10.1002/anie.201207966] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 11/28/2012] [Indexed: 12/25/2022]
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219
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Liu T, Bao C, Wang H, Lin Y, Jia H, Zhu L. Light-controlled ion channels formed by amphiphilic small molecules regulate ion conduction via cis–trans photoisomerization. Chem Commun (Camb) 2013; 49:10311-3. [DOI: 10.1039/c3cc45618h] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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220
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Zhang H, Tian Y, Jiang L. From symmetric to asymmetric design of bio-inspired smart single nanochannels. Chem Commun (Camb) 2013; 49:10048-63. [DOI: 10.1039/c3cc45526b] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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221
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Matsuo K, Kioi Y, Yasui R, Takaoka Y, Miki T, Fujishima SH, Hamachi I. One-step construction of caged carbonic anhydrase I using a ligand-directed acyl imidazole-based protein labeling method. Chem Sci 2013. [DOI: 10.1039/c3sc50560j] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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222
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Abstract
The Martini force field is a coarse-grained force field suited for molecular dynamics simulations of biomolecular systems. The force field has been parameterized in a systematic way, based on the reproduction of partitioning free energies between polar and apolar phases of a large number of chemical compounds. In this chapter the methodology underlying the force field is presented together with details of its parameterization and limitations. Then currently available topologies are described with a short overview of the key elements of their parameterization. These include the new polarizable Martini water model. A set of three selected ongoing studies using the Martini force field is presented. Finally the latest lines of development are discussed.
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223
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224
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Ivashenko O, van Herpt JT, Rudolf P, Feringa BL, Browne WR. Oxidative electrochemical aryl C–C coupling of spiropyrans. Chem Commun (Camb) 2013; 49:6737-9. [DOI: 10.1039/c3cc42396d] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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225
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Halža E, Bro TH, Bilenberg B, Koçer A. Well-Defined Microapertures for Ion Channel Biosensors. Anal Chem 2012; 85:811-5. [DOI: 10.1021/ac303005g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Erik Halža
- Groningen Biomolecular Sciences and Biotechnology Institute & BioMaDe Technology Foundation, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | | | - Brian Bilenberg
- NIL Technology ApS, Diplomvej 381, DK-2800, Kongens Lyngby, Denmark
| | - Armağan Koçer
- Groningen Biomolecular Sciences and Biotechnology Institute & BioMaDe Technology Foundation, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
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226
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Wen L, Liu Q, Ma J, Tian Y, Li C, Bo Z, Jiang L. Malachite green derivative-functionalized single nanochannel: light-and-pH dual-driven ionic gating. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:6193-8. [PMID: 23019021 DOI: 10.1002/adma.201202673] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 09/18/2012] [Indexed: 05/12/2023]
Abstract
A highly efficient and perfectly reversible ionic gate that can be activated by pH or UV light is demonstrated. Switching between the OFF state and the ON state is mainly dependent on the surface charge transition brought about by a malachite green derivative attached to the interior surface of an ion track-etched conical nanochannel, which makes it suitable for confined spaces. Applications in electronics, actuators, and biosensors can be foreseen.
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Affiliation(s)
- Liping Wen
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
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227
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Doerner JF, Febvay S, Clapham DE. Controlled delivery of bioactive molecules into live cells using the bacterial mechanosensitive channel MscL. Nat Commun 2012; 3:990. [PMID: 22871809 PMCID: PMC3651673 DOI: 10.1038/ncomms1999] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 07/10/2012] [Indexed: 12/22/2022] Open
Abstract
Bacterial mechanosensitive channels are some of the largest pores in nature. In particular, MscL, with a pore diameter >25 Å, allows passage of large organic ions and small proteins. Functional MscL reconstitution into lipids has been proposed for applications in vesicular-based drug release. Here we show that these channels can be functionally expressed in mammalian cells to afford rapid controlled uptake of membrane-impermeable molecules. We first demonstrate that MscL gating in response to increased membrane tension is preserved in mammalian cell membranes. Molecular delivery is controlled by adopting an established method of MscL charge-induced activation. We then determine pore size limitations using fluorescently labelled model cargoes. Finally, we activate MscL to introduce the cell-impermeable bi-cyclic peptide phalloidin, a specific marker for actin filaments, into cells. We propose that MscL will be a useful tool for gated and controlled delivery of bioactive molecules into cells.
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Affiliation(s)
- Julia F Doerner
- HHMI, Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts 02115, USA
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228
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Shrestha TB, Kalita M, Pokhrel MR, Liu Y, Troyer DL, Turro C, Bossmann SH, Dürr H. Maleimide-functionalized photochromic spirodihydroindolizines. J Org Chem 2012; 78:1903-9. [PMID: 23095100 DOI: 10.1021/jo301894s] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two photochromic spirodihydroindolizine/betaine systems for tethering to peptides and proteins via a maleimide function have been prepared. The absorption spectra of the betaines are in the red region of the visible spectrum and in the near-IR spectral domain, which are suitable energies of light for future in vivo applications. The half-times of cyclization have been determined for both DHI/betaine systems. The findings are consistent with a thermal barrier of varying size between the transoid and cisoid conformers of the betaines.
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Affiliation(s)
- Tej B Shrestha
- Department of Anatomy & Physiology, Kansas State University, Coles 130, Manhattan, Kansas 66506, United States.
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229
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Hansen MB, van Gaal E, Minten I, Storm G, van Hest JC, Löwik DW. Constrained and UV-activatable cell-penetrating peptides for intracellular delivery of liposomes. J Control Release 2012; 164:87-94. [DOI: 10.1016/j.jconrel.2012.10.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 10/09/2012] [Accepted: 10/09/2012] [Indexed: 10/27/2022]
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230
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Jang AR, Jeon EK, Kang D, Kim G, Kim BS, Kang DJ, Shin HS. Reversibly light-modulated dirac point of graphene functionalized with spiropyran. ACS NANO 2012; 6:9207-13. [PMID: 22980316 DOI: 10.1021/nn303539y] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Graphene has been functionalized with spiropyran (SP), a well-known photochromic molecule. It has been realized with pyrene-modified SP, which has been adsorbed on graphene by π-π interaction between pyrene and graphene. The field-effect transistor (FET) with SP-functionalized graphene exhibited n-doping effect and interesting optoelectronic behaviors. The Dirac point of graphene in the FET could be controlled by light modulation because spiropyran can be reversibly switched between two different conformations, a neutral form (colorless SP) and a charge-separated form (purple colored merocyanine, MC), on UV and visible light irradiation. The MC form is produced during UV light irradiation, inducing the shift of the Dirac point of graphene toward negative gate voltage. The reverse process back to the neutral SP form occurred under visible light irradiation or in darkness, inducing a shift of the Dirac point toward positive gate voltage. The change of the Dirac point by UV and visible light was reproducibly repeated. SP molecules also improved the conductance change in the FET device. Furthermore, dynamics on conversion from MC to SP on graphene was different from that in solution and solid samples with SP-grafted polymer or that on gold nanoparticles.
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Affiliation(s)
- A-Rang Jang
- Interdisciplinary School of Green Energy, Low Dimensional Carbon Materials Center, KIER-UNIST Advanced Center for Energy, Ulsan National Institute of Science & Technology (UNIST), UNIST-gil 50, Ulsan 689-805, Korea
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231
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Nanopore sensors: From hybrid to abiotic systems. Biosens Bioelectron 2012; 38:1-10. [DOI: 10.1016/j.bios.2012.05.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 05/02/2012] [Accepted: 05/12/2012] [Indexed: 11/22/2022]
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232
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Deplazes E, Louhivuori M, Jayatilaka D, Marrink SJ, Corry B. Structural investigation of MscL gating using experimental data and coarse grained MD simulations. PLoS Comput Biol 2012; 8:e1002683. [PMID: 23028281 PMCID: PMC3447979 DOI: 10.1371/journal.pcbi.1002683] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 07/21/2012] [Indexed: 12/02/2022] Open
Abstract
The mechanosensitive channel of large conductance (MscL) has become a model system in which to understand mechanosensation, a process involved in osmoregulation and many other physiological functions. While a high resolution closed state structure is available, details of the open structure and the gating mechanism remain unknown. In this study we combine coarse grained simulations with restraints from EPR and FRET experiments to study the structural changes involved in gating with much greater level of conformational sampling than has previously been possible. We generated a set of plausible open pore structures that agree well with existing open pore structures and gating models. Most interestingly, we found that membrane thinning induces a kink in the upper part of TM1 that causes an outward motion of the periplasmic loop away from the pore centre. This previously unobserved structural change might present a new mechanism of tension sensing and might be related to a functional role in osmoregulation. Cells in biological organisms have to be able to respond to mechanical forces during processes such as touch, hearing, pain sensation and tissue growth. One way this is achieved is through mechanosensitive ion channels, membrane embedded proteins that initiate electrical signalling upon tension within the cell or cell membrane. The malfunction of such channels is also associated with a range of diseases including muscular dystrophy and cardiac arrhythmia. In this manuscript, we study in detail the mechanosensitive channel of large conductance (MscL) from bacteria, a model system in which to understand the principles of mechanosensation. Despite many years of investigative work the details of how the protein senses tension in the surrounding membrane remain unknown. By combining structural data from experiments with computer simulation we are able to model the open channel structure of the protein and report previously unobserved structural changes that might present a new mechanism of sensing tension. The methods developed in this paper are not limited to the study of mechanosensitive ion channels and may be useful in understanding the structure and function of other membrane proteins.
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Affiliation(s)
- Evelyne Deplazes
- School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia, Perth, Australia
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233
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Suzuki Y, Okuro K, Takeuchi T, Aida T. Friction-Mediated Dynamic Disordering of Phospholipid Membrane by Mechanical Motions of Photoresponsive Molecular Glue: Activation of Ion Permeation. J Am Chem Soc 2012; 134:15273-6. [DOI: 10.1021/ja3074424] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yushi Suzuki
- Department of Chemistry and Biotechnology,
School of
Engineering, The University of Tokyo, 7-3-1
Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kou Okuro
- Department of Chemistry and Biotechnology,
School of
Engineering, The University of Tokyo, 7-3-1
Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Tadashi Takeuchi
- Department of Chemistry and Biotechnology,
School of
Engineering, The University of Tokyo, 7-3-1
Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Takuzo Aida
- Department of Chemistry and Biotechnology,
School of
Engineering, The University of Tokyo, 7-3-1
Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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234
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López-Gallego F, Abian O, Guisán JM. Altering the Interfacial Activation Mechanism of a Lipase by Solid-Phase Selective Chemical Modification. Biochemistry 2012; 51:7028-36. [DOI: 10.1021/bi300799v] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fernando López-Gallego
- Departamento de Biocatálisis,
Instituto de Catálisis y Petroleoquímica, CSIC, Campus UAM, Cantoblanco, C/Marie Curie n 2, 28049
Madrid, Spain
| | - Olga Abian
- Instituto
Aragonés de
Ciencias de la Salud (I+CS), Unidad de Investigación Traslacional, Hospital Universitario Miguel Servet,
Zaragoza, Spain, and Instituto de Investigación Sanitaria Aragón
(IIS Aragón), CIBERehd
- Instituto de Biocomputación
y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, Spain
| | - Jose Manuel Guisán
- Departamento de Biocatálisis,
Instituto de Catálisis y Petroleoquímica, CSIC, Campus UAM, Cantoblanco, C/Marie Curie n 2, 28049
Madrid, Spain
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235
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Fomina N, Sankaranarayanan J, Almutairi A. Photochemical mechanisms of light-triggered release from nanocarriers. Adv Drug Deliv Rev 2012; 64:1005-20. [PMID: 22386560 PMCID: PMC3395781 DOI: 10.1016/j.addr.2012.02.006] [Citation(s) in RCA: 343] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 02/16/2012] [Accepted: 02/16/2012] [Indexed: 12/18/2022]
Abstract
Over the last three decades, a handful of photochemical mechanisms have been applied to a large number of nanoscale assemblies that encapsulate a payload to afford spatio-temporal and remote control over activity of the encapsulated payload. Many of these systems are designed with an eye towards biomedical applications, as spatio-temporal and remote control of bioactivity would advance research and clinical practice. This review covers five underlying photochemical mechanisms that govern the activity of the majority of photoresponsive nanocarriers: 1. photo driven isomerization and oxidation, 2. surface plasmon absorption and photothermal effects, 3. photo driven hydrophobicity changes, 4. photo driven polymer backbone fragmentation and 5. photo driven de-crosslinking. The ways in which these mechanisms have been incorporated into nanocarriers and how they affect release are detailed, as well as the advantages and disadvantages of each system.
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Affiliation(s)
- Nadezda Fomina
- University of California San Diego, Skaggs School of Pharmacy & Pharmaceutical Sciences, Dept. of Materials Science and Engineering, Dept. of NanoEngineering, 9500 Gilman Dr. MC 0660, La Jolla, CA, USA
| | - Jagadis Sankaranarayanan
- University of California San Diego, Skaggs School of Pharmacy & Pharmaceutical Sciences, Dept. of Materials Science and Engineering, Dept. of NanoEngineering, 9500 Gilman Dr. MC 0660, La Jolla, CA, USA
| | - Adah Almutairi
- University of California San Diego, Skaggs School of Pharmacy & Pharmaceutical Sciences, Dept. of Materials Science and Engineering, Dept. of NanoEngineering, 9500 Gilman Dr. MC 0660, La Jolla, CA, USA
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236
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Brieke C, Rohrbach F, Gottschalk A, Mayer G, Heckel A. Light-controlled tools. Angew Chem Int Ed Engl 2012; 51:8446-76. [PMID: 22829531 DOI: 10.1002/anie.201202134] [Citation(s) in RCA: 738] [Impact Index Per Article: 61.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Indexed: 12/21/2022]
Abstract
Spatial and temporal control over chemical and biological processes plays a key role in life, where the whole is often much more than the sum of its parts. Quite trivially, the molecules of a cell do not form a living system if they are only arranged in a random fashion. If we want to understand these relationships and especially the problems arising from malfunction, tools are necessary that allow us to design sophisticated experiments that address these questions. Highly valuable in this respect are external triggers that enable us to precisely determine where, when, and to what extent a process is started or stopped. Light is an ideal external trigger: It is highly selective and if applied correctly also harmless. It can be generated and manipulated with well-established techniques, and many ways exist to apply light to living systems--from cells to higher organisms. This Review will focus on developments over the last six years and includes discussions on the underlying technologies as well as their applications.
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Affiliation(s)
- Clara Brieke
- Goethe University Frankfurt, Institute for Organic Chemistry and Chemical Biology Buchmann Institute for Molecular Life Sciences, Max-von-Laue-Strasse 9, 60438 Frankfurt/Main, Germany
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237
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Brieke C, Rohrbach F, Gottschalk A, Mayer G, Heckel A. Lichtgesteuerte Werkzeuge. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201202134] [Citation(s) in RCA: 225] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Clara Brieke
- Goethe‐Universität Frankfurt, Institut für Organische Chemie und Chemische Biologie, Buchmann‐Institut für Molekulare Lebenswissenschaften, Max‐von‐Laue‐Straße 9, 60438 Frankfurt/Main (Deutschland)
| | - Falk Rohrbach
- Universität Bonn, LIMES‐Institut, Gerhard‐Domagk‐Straße 1, 53121 Bonn (Deutschland)
| | - Alexander Gottschalk
- Buchmann‐Institut für Molekulare Lebenswissenschaften, Institut für Biochemie, Max‐von‐Laue‐Straße 15, 60438 Frankfurt/Main (Deutschland)
| | - Günter Mayer
- Universität Bonn, LIMES‐Institut, Gerhard‐Domagk‐Straße 1, 53121 Bonn (Deutschland)
| | - Alexander Heckel
- Goethe‐Universität Frankfurt, Institut für Organische Chemie und Chemische Biologie, Buchmann‐Institut für Molekulare Lebenswissenschaften, Max‐von‐Laue‐Straße 9, 60438 Frankfurt/Main (Deutschland)
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238
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Fleige E, Quadir MA, Haag R. Stimuli-responsive polymeric nanocarriers for the controlled transport of active compounds: concepts and applications. Adv Drug Deliv Rev 2012; 64:866-84. [PMID: 22349241 DOI: 10.1016/j.addr.2012.01.020] [Citation(s) in RCA: 749] [Impact Index Per Article: 62.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 01/25/2012] [Accepted: 01/27/2012] [Indexed: 01/08/2023]
Abstract
The use of polymeric nanocarriers to transport active compounds like small-molecular drugs, peptides, or genes found an increased attention throughout the different fields of natural sciences. Not only that these nanocarriers enhance the properties of already existing drugs in terms of solubility, bioavailability, and prolonged circulation times, furthermore they can be tailor-made in such a manner that they selectively release their cargo at the desired site of action. For the triggered release, these so-called smart drug delivery systems are designed to react on certain stimuli like pH, temperature, redox potential, enzymes, light, and ultrasound. Some of these stimuli are naturally occurring in vivo, for example the difference in pH in different cellular compartments while others are caused by the disease, which is to be treated, like differences in pH and temperature in some tumor tissues. Other external applied stimuli, like light and ultrasound, allow the temporal and spatial control of the release, since they are not triggered by any biological event. This review gives a brief overview about some types of stimuli-responsive nanocarriers with the main focus on organic polymer-based systems. Furthermore, the different stimuli and the design of corresponding responsive nanocarriers will be discussed with the help of selected examples from the literature.
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239
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The MscS and MscL families of mechanosensitive channels act as microbial emergency release valves. J Bacteriol 2012; 194:4802-9. [PMID: 22685280 DOI: 10.1128/jb.00576-12] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Single-celled organisms must survive exposure to environmental extremes. Perhaps one of the most variable and potentially life-threatening changes that can occur is that of a rapid and acute decrease in external osmolarity. This easily translates into several atmospheres of additional pressure that can build up within the cell. Without a protective mechanism against such pressures, the cell will lyse. Hence, most microbes appear to possess members of one or both families of bacterial mechanosensitive channels, MscS and MscL, which can act as biological emergency release valves that allow cytoplasmic solutes to be jettisoned rapidly from the cell. While this is undoubtedly a function of these proteins, the discovery of the presence of MscS homologues in plant organelles and MscL in fungus and mycoplasma genomes may complicate this simplistic interpretation of the physiology underlying these proteins. Here we compare and contrast these two mechanosensitive channel families, discuss their potential physiological roles, and review some of the most relevant data that underlie the current models for their structure and function.
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240
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Abstract
A compact or portable mechatronic embedded system application has a strictly demands of volume and/or power consuming. Comparing with electronic parts, switches and/or actuators take the most proportion of volume or weight and power consuming of the whole system. A novel method of connecting multiple switches/actuators built by using electro-rheological fluid and a pair of governing electrodes and their control strategy are introduced in this paper. By using this method, the numbers of control components are changed from N times M to N plus M, the volume and weight reduced largely.A series structure is used in the application on multi-line Braille electro-book for blind people as a demonstration of this novel method. It provides a novel solution of shrinking system for a compact or portable mechatronic embedded system application.
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241
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Zhang M, Hou X, Wang J, Tian Y, Fan X, Zhai J, Jiang L. Light and pH cooperative nanofluidic diode using a spiropyran-functionalized single nanochannel. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:2424-8. [PMID: 22488964 DOI: 10.1002/adma.201104536] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Revised: 01/13/2012] [Indexed: 05/26/2023]
Abstract
An artificial nanofluidic diode system is prepared, mimicking the light-gated and pH-tunable ion channels that play an important role in life sciences. When UV light is off, the nanochannel is in the closed state, analogous to a resistance. Under UV light irradiation and at pH 7, the current flows from the tip to the base, analogous to a diode; at pH 3, the situation (and the diode) is reversed.
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Affiliation(s)
- Minghui Zhang
- Key Laboratory of Bio-Inspired Smart Interfacial, Science and Technology of the Ministry of Education, School of Chemistry and the Environment, Beihang University, Beijing, P. R. of China.
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242
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Numata T, Murakami T, Kawashima F, Morone N, Heuser JE, Takano Y, Ohkubo K, Fukuzumi S, Mori Y, Imahori H. Utilization of Photoinduced Charge-Separated State of Donor–Acceptor-Linked Molecules for Regulation of Cell Membrane Potential and Ion Transport. J Am Chem Soc 2012; 134:6092-5. [DOI: 10.1021/ja3007275] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomohiro Numata
- Department
of Synthetic Chemistry
and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Tatsuya Murakami
- Institute for Integrated Cell-Material
Sciences (WPI-iCeMS), Kyoto University,
Sakyo-ku, Kyoto 606-8501, Japan
| | - Fumiaki Kawashima
- Department of Molecular Engineering,
Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Nobuhiro Morone
- Institute for Integrated Cell-Material
Sciences (WPI-iCeMS), Kyoto University,
Sakyo-ku, Kyoto 606-8501, Japan
| | - John E. Heuser
- Institute for Integrated Cell-Material
Sciences (WPI-iCeMS), Kyoto University,
Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuta Takano
- Institute for Integrated Cell-Material
Sciences (WPI-iCeMS), Kyoto University,
Sakyo-ku, Kyoto 606-8501, Japan
| | - Kei Ohkubo
- Department of Material and Life
Science, Graduate School of Engineering, Osaka University, and ALCA, Japan Science and Technology Agency (JST), Suita, Osaka
565-0871, Japan
| | - Shunichi Fukuzumi
- Department of Material and Life
Science, Graduate School of Engineering, Osaka University, and ALCA, Japan Science and Technology Agency (JST), Suita, Osaka
565-0871, Japan
- Department
of Bioinspired Science, Ewha Womans University, Seoul 120-750, Korea
| | - Yasuo Mori
- Department
of Synthetic Chemistry
and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Hiroshi Imahori
- Institute for Integrated Cell-Material
Sciences (WPI-iCeMS), Kyoto University,
Sakyo-ku, Kyoto 606-8501, Japan
- Department of Molecular Engineering,
Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
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243
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244
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Nicoletta FP, Cupelli D, Formoso P, De Filpo G, Colella V, Gugliuzza A. Light responsive polymer membranes: a review. MEMBRANES 2012; 2:134-97. [PMID: 24957966 PMCID: PMC4021883 DOI: 10.3390/membranes2010134] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/04/2012] [Accepted: 02/16/2012] [Indexed: 12/04/2022]
Abstract
In recent years, stimuli responsive materials have gained significant attention in membrane separation processes due to their ability to change specific properties in response to small external stimuli, such as light, pH, temperature, ionic strength, pressure, magnetic field, antigen, chemical composition, and so on. In this review, we briefly report recent progresses in light-driven materials and membranes. Photo-switching mechanisms, valved-membrane fabrication and light-driven properties are examined. Advances and perspectives of light responsive polymer membranes in biotechnology, chemistry and biology areas are discussed.
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Affiliation(s)
| | - Daniela Cupelli
- Department of Pharmaceutical Sciences, Università della Calabria, I-87036 Rende (CS), Italy.
| | - Patrizia Formoso
- Department of Pharmaceutical Sciences, Università della Calabria, I-87036 Rende (CS), Italy.
| | - Giovanni De Filpo
- Department of Chemistry, Università della Calabria, I-87036 Rende (CS), Italy.
| | - Valentina Colella
- Department of Pharmaceutical Sciences, Università della Calabria, I-87036 Rende (CS), Italy.
| | - Annarosa Gugliuzza
- Institute on Membrane Technology-National Council Research, ITM-CNR, I-87030 Rende (CS), Italy.
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245
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Affiliation(s)
- Yue Zhao
- Département de chimie, Université de Sherbrooke, Sherbrooke, Québec,
Canada J1K 2R1
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246
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Yang LM, Wray R, Parker J, Wilson D, Duran RS, Blount P. Three routes to modulate the pore size of the MscL channel/nanovalve. ACS NANO 2012; 6:1134-1141. [PMID: 22206349 PMCID: PMC3289768 DOI: 10.1021/nn203703j] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
MscL is a bacterial mechanosensitive channel that protects cells from lysis upon acute decrease in external osmotic environment. It is one of the best characterized mechanosensors known, thus serving as a paradigm of how such molecules sense and respond to stimuli. In addition, the fact that it can be genetically modified, expressed, isolated, and manipulated has led to its proposed use as a triggered nanovalve for various functions including sensors within microelectronic array chips, as well as vesicular-based targeted drug release. X-ray crystallography reveals a homopentameric complex with each subunit containing two transmembrane α-helices (TM1 and TM2) and a single carboxyl terminal α-helix arranging within the complex to form a 5-fold cytoplasmic bundle (CB), whose function and stability remain unclear. In this study, we show three routes that throttle the open channel conductance. When the linker between the TM2 and CB domain is shortened by deletions or constrained by either cross-linking or heavy metal coordination, the conductance of the channel is reduced; in the later two cases, even reversibly. While they have implications for the stability of the CB, these data also provide routes for engineering MscL sensors that are more versatile for potential nanotech devices.
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Affiliation(s)
- Li-Min Yang
- Department of Physiology, University of Texas Medical Center at Dallas, Dallas, Texas, USA
| | - Robin Wray
- Department of Physiology, University of Texas Medical Center at Dallas, Dallas, Texas, USA
| | - Juandell Parker
- Department of Physiology, University of Texas Medical Center at Dallas, Dallas, Texas, USA
| | - Danyell Wilson
- Department of Chemistry, University of Florida, current address Moffitt Cancer Center, Tampa, FL
| | - Randolph S. Duran
- Department of Chemistry, Louisiana State University, Baton Rouge, LA
| | - Paul Blount
- Department of Physiology, University of Texas Medical Center at Dallas, Dallas, Texas, USA
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247
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Dube H, Rebek J. Selective Guest Exchange in Encapsulation Complexes Using Light of Different Wavelenghts. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201108074] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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248
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Dube H, Rebek J. Selective Guest Exchange in Encapsulation Complexes Using Light of Different Wavelenghts. Angew Chem Int Ed Engl 2012; 51:3207-10. [DOI: 10.1002/anie.201108074] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 01/04/2012] [Indexed: 11/10/2022]
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249
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Mechanosensitive channels: what can they do and how do they do it? Structure 2012; 19:1356-69. [PMID: 22000509 DOI: 10.1016/j.str.2011.09.005] [Citation(s) in RCA: 240] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 09/19/2011] [Accepted: 09/20/2011] [Indexed: 12/16/2022]
Abstract
While mechanobiological processes employ diverse mechanisms, at their heart are force-induced perturbations in the structure and dynamics of molecules capable of triggering subsequent events. Among the best characterized force-sensing systems are bacterial mechanosensitive channels. These channels reflect an intimate coupling of protein conformation with the mechanics of the surrounding membrane; the membrane serves as an adaptable sensor that responds to an input of applied force and converts it into an output signal, interpreted for the cell by mechanosensitive channels. The cell can exploit this information in a number of ways: ensuring cellular viability in the presence of osmotic stress and perhaps also serving as a signal transducer for membrane tension or other functions. This review focuses on the bacterial mechanosensitive channels of large (MscL) and small (MscS) conductance and their eukaryotic homologs, with an emphasis on the outstanding issues surrounding the function and mechanism of this fascinating class of molecules.
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250
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Rossi Paccani R, Donati D, Fusi S, Latterini L, Farina G, Zanirato V, Olivucci M. Toward a stable α-cycloalkyl amino acid with a photoswitchable cationic side chain. J Org Chem 2012; 77:1738-48. [PMID: 22239068 DOI: 10.1021/jo2022263] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The N-alkylated indanylidenepyrroline (NAIP) Schiff base 3 is an unnatural α-amino acid precursor potentially useful for the preparation of semisynthetic peptides and proteins incorporating charged side chains whose structure can be modulated via Z/E photoisomerization. Here we report that the heteroallylic protons of 3 led to partial loss of ethanol accompanied by formation of the novel heterocyclic system 4 during attempted deprotection. We also show that the same protons catalyze the thermal isomerization of 3, making the light-driven conformational control concept ineffective for times longer than a few hours. These problems are not present in the previously unreported compound 5 where the acidic methyl group is replaced by an H atom. Therefore, 5, rather than 3, constitutes a promising prototype for the design of building blocks capable to modulate the electrostatic potential of a protein in specific locations via light irradiation.
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