Hot Chemical Science articles for June

All of the referee-recommended articles below are free to access until 21st July:

A full-adder based on reconfigurable DNA-hairpin inputs and DNAzyme computing modules
Ron Orbach, Fuan Wang, Oleg Lioubashevski, R. D. Levine, Francoise Remacle and Itamar Willner  
Chem. Sci., 2014, Advance Article
DOI: 10.1039/C4SC00914B, Edge Article


Millisecond lifetime imaging with europium complex using a commercial confocal microscope under one or two-photon excitations
Olivier Maury, Alexandre Haefele, Simon Pascal, Chantal Andraud, Alexei Grichine, Alain DUPERRAY and Richard MICHEL  
Chem. Sci., 2014, Accepted Manuscript
DOI: 10.1039/C4SC00473F, Edge Article

 


Supramolecular chemistry with ureido-benzoic acids
E W Meijer, Anja R. A. Palmans, Wilco Appel, Bas FM de Waal, Marko Nieuwenhuizen and Martin Lutz  
Chem. Sci., 2014, Accepted Manuscript
DOI: 10.1039/C4SC00871E, Edge Article


Synthesis and Chemoselective Ligations of MIDA Acylboronates with O-Me Hydroxylamines
Hidetoshi Noda and Jeffrey W Bode  
Chem. Sci., 2014, Accepted Manuscript
DOI: 10.1039/C4SC00971A, Edge Article

  

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Artificial ion channels that work on a feedback loop

written by Cally Haynes, a Publishing Editor at the Royal Society of Chemistry

In nature, many cellular processes are controlled by structures that are only assembled when they are needed, in response to a chemical energy input. The structure (and hence the action of the structure) is maintained so long as the chemical energy input, or ‘fuel’ for the process is present. For example, microtubules can ‘grow’ or ‘shrink’ depending on the presence of guanosine triphosphate (GTP), and hence GTP serves as a ‘fuel’ for the function of the microtubules.

Inspired by this principle, Tom Fyles and his team from University of Victoria, Canada have used thiol–thioester exchange chemistry to assemble a metastable ion channel that disassembles over time in the absence of a chemical fuel.

In the scheme below, thiol 4 is not an active ion channel, but the addition of thioester 5 causes the formation of 3 by thiol-thioester exchange. 3 forms an active ion channel, but is metastable and therefore over time it disassembles into 4 + 6 which stops the ion transport. Adding more 5 (the fuel) will temporarily regenerate the ion transport as more C is formed.

While this system functions exactly as planned, its design was not without complications, says Fyles: “One setback was that these compounds do not work in vesicles so we had to develop reaction monitoring techniques using the bilayer clamp experiment.  That gives us exquisite sensitivity, but also allows us to detect very minor amounts of impurities.  So another setback was the observation that an oxidation impurity was vastly more active than the compounds we wanted to see.  This problem was easy enough to solve, but it took some time to recognize what was going on.”

This work also opens up exciting new avenues of investigation for the future for Fyles and his team. “The more general insight is that this system depends entirely on kinetic factors.  As chemists we are used to thinking about rates in terms of the reaction order and uniform reactant concentrations in the bulk.  Our system additionally shows the importance of local concentrations as opposed to the bulk concentration.  This introduces additional kinetic components related to diffusion.  The functioning of our system recorded using the bilayer clamp is largely controlled by diffusion processes, rather than the reaction kinetics we control in the design of the system.  This suggests that we might be able to make other systems that deliberately exploit non-uniform concentrations – yet another feature we can see in nature. Stay tuned.”

To download the full article for free*, click the link below:

Dissipative Assembly of a Membrane Transport System
A. K. Dambenieks, P. H. Q. Vu and T. M. Fyles
DOI: 10.1039/C4SC01258E

*Access is free untill the 17.07.14 through a registered RSC account – click here to register

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Excellent visibility for your research

We want our authors’ research to get the visibility and recognition it deserves.

Chemical Science is dedicated to publishing findings of exceptional significance from across the chemical sciences.

The graph below shows the number of citations to articles published in 2013 in Chemical Science and other leading general chemistry journals. 

It’s clear to see from this data that articles in Chemical Science are less likely to receive no citations and after just a few months of publication articles will be highly cited - 45% of 2013 Chemical Science articles have already received 5 or more citations.

Publishing your research in Chemical Science means your article will have excellent visibility and will be read and cited quickly by your colleagues.

Chemical Science Citations

Citations to articles published in 2013 (Data downloaded from ISI Web of Science on 6 June 2014)

Browse the latest articles from Chemical Science here


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Triptycene based hole transport materials for dye sensitized solar cells

Researchers from China have synthesized three novel hole-conducting molecules which may give rise to significant economic advantages for the production of dye sentisized solar cells. Web writer Kevin writes more…

Dye sensitized solar cells (DSSCs) are photovoltaic devices which use a sensitizer in combination with a photosensitive material and a wide band gap semiconductor to produce an electric current. Thin-film DSSCs can offer packaging and application opportunites, have potential as functional coatings, and exhibit high power conversion efficiencies (PCE) of up to 12-13%.

Current state-of-the-art dye sensitized solar cells are usually solid phase systems, removing any issues surrounding leakage of components or the corrosive nature of some electrolytes. In such configurations a constituent known as a hole transport material (HTM) is now commonly used instead of a liquid electrolyte.

In this Chemical Science Edge article, authors from the Energy Research Institute, Nanyang, and the Nanyang Technological University, Singapore, give details of a group of triptycene based molecules which, they claim, perform on a comparable level with the current best in class HTM, (spiro-OMeTAD). The materials described were prepared from a starting tri-iodotryptycene material which was derivatised using a variety of transformations including Stille and Suzuki coupling reactions. The materials contain diphenylamine moieties separated from the triptycene core by aromatic spacers, enabling charge transfer.

These materials were fabricated in a complex process into a typical DSSC, containing fluorine doped tin oxide, semiconducting titanium dioxide and lead iodide perovskite dye sensitizer material. Power conversion efficiencies are comparable to devices comprimising the best performing HTMs. For the T102 andT103 derivatives, PCEs were reported as 12.24 and 12.38%, comparable to devices fabricated with spiro-OMeTAD (12.78%). Without a HTM present the number falls to less than 5%.

This article presents details of promising HTM materials which may give rise to significant economic advantages for the production and commercialisation of solid state DSSCs, with current best in class performance levels.

Read this HOT Chemical Science Edge Article for free* today:

Novel hole transporting materials based on triptycene core for high efficiency mesoscopic perovskite solar cells

Anurag Krishna, Dharani Sabba, Hairong Li, Jun Yin, Pablo P. Boix, Cesare Soci, Subodh G. Mhaisalkar and  Andrew C. Grimsdale
DOI: 10.1039/C4SC00814F

About the webwriter

Kevin Murnaghan is a guest web-writer for Chemical Communications. He is currently a Research Chemist in the Adhesive Technologies Business Sector of Henkel AG & Co. KGaA, based in Düsseldorf, Germany. His research interests focus primarily on enabling chemistries and technologies for next generation adhesives and surface treatments. Any views expressed here are his personal ones and not those of Henkel AG & Co. KGaA.

*Access is free untill the 11.07.14 through a registered RSC account – click here to register

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Fighting cancer with artificial antigen-presenting cells

Researchers from the Netherlands discuss the development of artificial antigen-presenting cells

Antigen-presenting cells (ACPs) are key players in the immune systems fight against cancer. On detection of tumor tissues, these ACPs pick up antigenic fragments of the tumor cell, migrate to the lymphoid organs and present the antigen to T-cells which play a central role in cell mediated immunity. Therefore, artificial ACPs (aAPCs) are often used in the development of immune-mediated anti-cancer therapies as they show great potential to mimic antigen-presentation, promoting T-cell activation.

Carl Figdor, a world-class immunologist, and colleagues from Radbound University discuss the current status of aAPC development in a Chemical Science Perspective. This review is partly focused on the developments in nanoscience which might improve future designs for immune-mediated anti-cancer therapies.

As a synthetic mimic, aAPCs must encompass the three signals that natural APCs use to encourage T-cell activation. This perspective discusses how these signals have been incorporated into aAPC designs, but also how physical properties such a size and shape are essential for targeting the aAPCs to T-cell rich areas in vivo.

Artificial antigen-presenting cells have the potential to develop into a widespread and powerful therapeutic tool. To download the full perspective, click on the link below – access is free for a limited time only!

Joep van der Weijden, Leonie Paulis, Martijn Verdoes, Jan C M van Hest and Carl Figdor
DOI: 10.1039/C4SC01112K
Looking for the best articles at the chemistry-biology interface. Check out our Chemical Biology Themed Collection showcasing some of the great research papers and reviews published in Chemical Science, in the areas of chemical biology and bioinorganic chemistry.
*Access is free through a registered RSC account – click here to register
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A Faraday Discussion – Nanoparticle Synthesis and Assembly

Abstract submission is now open – submit your oral abstract by 21 July 2014

How does the nanoparticle-nanoparticle potential govern nanoparticle formation or assembly? Can one make more robust nanoparticle superlattice structures, which can be moulded, milled and machined into desired shapes? How does the assembly process vary with nanoparticle shape?

These questions cannot be answered in isolation – join the Nanoparticle Synthesis and Assembly, a Faraday Discussion which will be held on 20-22 April 2015 in Chicago, USA.

Abstract submission is now open, so take advantage of this excellent opportunity to showcase your latest research alongside leading scientists from across the globe. Don’t leave it too late – the deadline for oral abstracts is 21 July 2014.

Themes will include:

  • Nanoparticle synthesis – physical chemistry of nanoparticle shape and ligand control
  • Theoretical insights into nanoparticle synthesis and nanoparticle assembly
  • Nanoparticle self-assembly
  • Nanoparticle directed assembly

For more information and to see details of the speakers, visit the event website.

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The Importance of Biometal Distribution in Neurodegenerative Disorders

Iain Larmour is a guest web writer for ChemSci. He has researched a wide variety of topics during his years in the lab including nanostructured surfaces for water repellency and developing nanoparticle systems for bioanalysis by surface enhanced optical spectroscopies. He currently works in science management. In his spare time he enjoys reading, photography, art and inventing.

Anthony White from the Department of Pathology, University of Melbourne and team have investigated the use of X-ray Fluorescence Microscopy to investigate subcellular biometal homeostasis in a mouse model of the childhood neurodegenerative disorder – Batten disease. This is a particularly nasty disease that causes progressive blindness and motor impairment leading to premature death. The team have previously highlighted the redistribution of brain zinc in diseased samples using subcellular fractionation techniques. However, the lack of a rapid, specific and sensitive technique to provide quantitative subcellular information in situ on biometal distributions is severely limiting the understanding of the effect that the changes in biometals distributions can have in neurodegenerative diseases.

Consider the next time you go food shopping. What if you arrived at the supermarket and all the shelves were empty. A shop assistant reassures you that there is plenty of stock, hundreds of thousands of items indeed, but it all just happens to be sitting in their central depot instead of the supermarket. This does not help you to make dinner that night. This scenario is an example of how important the distribution of items can be.

When it comes to neurodegenerative disorders the location of biometals, just like the location of the groceries in the above case, provides much more useful information than the total amount of biometal present. The amount of biometal may not change between normal and diseased cells, but the distribution does. Biometals are important cofactors to a large number of enzymes and are also recognised as second messengers in neuronal signalling

Intracellular zinc and calcium distributions mapped by x-ray fluorescence microscopy.

In their Chemical Science paper the team have utilised the advances in data collection speed of X-ray fluorescence detectors to map the zinc and calcium distributions in a statistically relevant number of cells. Despite a lack of global changes in biometal levels this approach revealed the perturbed trafficking of zinc and the significantly altered subcellular calcium distributions. The restorative properties of a therapeutic zinc-complex were also shown using this technique.

Techniques and methodology reported in the Chemical Science paper can be applied to other neurodegenerative diseases and importantly can provide insights to the mechanism of action of novel therapeutics at the single cell level.

Read the Chem. Sci. paper in full today for free* and see if this technique could be applied to a disease you are studying!

X-ray fluorescence imaging reveals subcellular biometal disturbances in a childhood neurodegenerative disorder
A. Grubman, S.A. James, J. James, C. Duncan, I. Volitakis, J.L. Hickey, P.J. Crouch, P.S. Donnelly, K.M. Kanninen, J.R. Liddell, S.L. Cotman, M.D. de Jonge and A.R. White*
DOI: 10.1039/C4SC00316K


*Access is free until 20.06.14 through a registered RSC account – click here to register

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Photooxidation system that’s membrane-bound for success

Polly Wilson writes about a hot Chemical Science article for Chemistry World

Photosensitiser–water oxidation catalysts in heterogeneous (top), membrane-bound (middle) and homogeneous (bottom) systems

For the first time, a water oxidation catalyst and photosensitiser have been co-embedded into a membrane to make an artificial water photooxidation system. The arrangement can generate oxygen from water at far lower catalyst concentrations than ever before.

Chemical systems to turn solar energy into fuel are of paramount importance in the quest for sustainable green energy. Mimicking natural photosynthesis, the aim is to achieve sunlight-driven conversion of water and carbon dioxide into carbohydrates and oxygen. One branch of the process involves photocatalytic water splitting, comprising oxidative and reductive half reactions. The more complex photoxidation step involves a four-electron transfer reaction and very reactive oxygen intermediates. In nature, this extremely endothermic reaction is performed by Photosystem II (PSII), using membrane bound chromophores and catalytic units.


Read the full article in Chemistry World»

Read the original journal article in Chemical Science – it’s free to download until 30th June:
Photocatalytic water oxidation at soft interfaces
Malte Hansen, Fei Li, Licheng Sun and Burkhard König
Chem. Sci., 2014, Advance Article
DOI: 10.1039/C4SC01018C, Edge Article

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Immunocamouflage lets donor blood cells go undetected

Kirsty Muirhead writes about a hot Chemical Science article for Chemistry World

Chinese scientists are developing a new approach to create “universal” blood: red blood cells (RBCs) that can be transfused into any patient, regardless of the patient or recipient blood group.

Blood groups are characterised by the presence (or absence) of various proteins known as antigens on the surface of RBCs, the most well-known of which form the ABO system and the Rhesus D (RhD) system. One consequence of the existence of these groups is that blood mismatching can occur when an incompatible blood group is used for transfusion. The recipient’s antibodies recognise the antigens on the donor RBCs as being foreign and attack the cells – with potentially fatal results.

Antigenic epitopes on RBCs are sheltered by polydopamine


Read the full article in Chemistry World»

Read the original journal article in Chemical Science – it’s free to access until 1st July:
Antigenic-sheltering universal red blood cells by polydopamine-based cell superficial-engineering
Ben Wang, Guangchuan Wang, Binjie Zhao, Jiajun Chen, Xueyun Zhang and Ruikang Tang  
Chem. Sci., 2014, Accepted Manuscript, DOI: 10.1039/C4SC01120A, Edge Article

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Challenges in Inorganic and Materials Chemistry (ISACS13) – register before 2 June

Challenges in Inorganic and Materials Chemistry - ISACS13
Don’t miss your chance to attend Challenges in Inorganic and Materials Chemistry (ISACS13)

Final registration deadline – Monday 2 June Register now

Register to join Guy Bertrand, Susumu Kitagawa and Douglas Stephan and a host of impressive speakers at Challenges in Inorganic and Materials Chemistry (ISACS13).

Spaces are filling up fast so guarantee your place now.

We look forward to welcoming you to Dublin this July.

Professor Thorri Gunnlaugsson Dr Robert D. Eagling
Conference Chair Editor, Chemical Science
P.S. Join us for the 5th Joint CSJ RSC Symposium on Supramolecular Chemistry which is being held on 1st July in Dublin, just before the start of ISACS13. It’s free to attend and registration is open now.

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