Archive for February, 2011

A new class of molecular propellers

Scientist based in Italy have recently demonstrated a new class of molecular propellers based upon polyoxometalates (POMs).

POMs consist of a cluster of transition metal oxides that are water soluble and are used for a wide range of applications. In particular, Andrea Sartorel and Marcella Bonchio, from the Univerity of Padova, are interested in their use as photosynthetic oxygen-evolving catalysts. The team studied a series of POMs with different metal centres and their catalytic performance in the disproportionation of hydrogen peroxide (H2O2) to water and oxygen.

They found that of all the POMS studied, Ru4(SiW10)2 performed the best in terms of oxygen evolution. This production of oxygen could then be used to create movement of the POM;  in effect using H2O2as fuel to create oxygen that then propels the POM material in aqueous solution. A video of this can be seen here. This represents a step towards the use of light-driven molecular machines based on POMs.

If you are interested in finding out more, then why not download Sartorel and Bonchio’s ChemComm article for free today? Also, don’t forget to leave a comment below!

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Intramolecular cycloaddition leads to the pentacyclic core of cortistatins

Synthesising intriguing bioactive natural products in the most expedient and atom-efficient manner remains a highly active and competitive field of research. Cortistatins A and J, first isolated from the marine sponge Corticium simplex in 2006, have been identified as effective anti-angiogenics, which studies have found could suppress cancer recurrence when given in conjunction with traditional cancer drugs.

Lok Lok Liu and Pauline Chiu at the University of Hong Kong have reported a concise, high yielding, asymmetric synthesis of the pentacyclic framework of the cortistatins, in 12 steps from commercially available starting materials. Their synthesis employs a highly diastereoselective intramolecular [4+3] cycloaddition of epoxy enolsilanes as the key step and brings them close to their ultimate goal.

To find out more, download the ChemComm communication for free up until March 28th

To start a discussion, leave your comments below and for a related blog post see the Totally Synthetic blog pages.

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Meet our author… Greg Qiao

Greg Qiao is a polymer scientist and engineer at the University of Melbourne in Australia. His research interests cover various polymerisation techniques, including controlled free radical polymerisations, in a bid to synthesise novel polymeric architectures, biodegradable and functional polymers.  

Qiao’s recent communication, published in ChemComm, touches upon his interest in using polymers as coatings for the automotive industry or as potential drug delivery vehicles: ‘Star Polymers Composed Entirely of Amino Acid Building Blocks: A Route towards Stereospecific, Biodegradable and Hierarchically Functionalized Stars 

Below, Greg takes some time away from his research to talk to us… 

What initially inspired you to become a scientist?
When I was a child, I always dreamed of becoming a scientist. I chose science and engineering as my major when starting university and fell in love with both chemistry and chemical engineering.  I’ve always believed that science and technology can change and improve life for the human society.

Greg Qiao

What was your motivation behind the work described in your ChemComm article?
My research group has spent over 10 years in the field of controlled synthesis and characterisation of core crosslinked star (CCS) polymers. We initially used controlled free radical polymerisation methods, including nitroxide–mediated polymerisation (NMP) and atom transfer radical polymerisation (ATRP) methods, to synthesise CCS polymers and study their properties including molecular morphology and solution rheology. We also studied CCS analogues for their suitability as additive to automotive paint.
 
Five years ago, we started to synthesise CCS polymers with alternative polymerisation methods including ring opening polymerisation (ROP) for selectively degradable CCS. More recently, we have been working on new ways to form CCS which is fully biodegradable and biocompatible.  In this work, we developed a new process by using peptide synthesis as a controlled chain growth method to produce CCS. This process not only uses entirely naturally occurred amino-acid precursors, but also provides more convenient approaches to functionalise CCS at its core, along the arms and at the end of the arms. We are hoping this work can lay foundation for the new peptide-based drug delivery vehicles.

 

Why did you choose ChemComm to publish your work?
Because of the fast and broad readership, as well as its high impact.
 
Where do you see your research heading next?
We wish to develop this unique peptide-based CCS as a drug carrier for delivering drugs to targeted cells. My other research direction is using the controlled polymerisation method to create an efficient and thickness-controlled surface coating technology. 
 
What do enjoy doing in your spare time?
Reading a good article that has a completely fresh, new idea.
 
If you could not be a scientist, but could be anything else, what would you be?
Politician or publican servant – something to serve the public.

Other polymer articles recently published  in ChemComm that might also interest you include:-

Emerging synthetic approaches for protein–polymer conjugations
Rebecca M. Broyer, Gregory N. Grover and Heather D. Maynard
Chem. Commun., 2011, 47, 2212-2226
DOI: 10.1039/C0CC04062B, Feature Article

 Functional, star polymeric molecular carriers, built from biodegradable microgel/nanogel cores
Jay A. Syrett, David M. Haddleton, Michael R. Whittaker, Thomas P. Davis and Cyrille Boyer
Chem. Commun., 2011, 47, 1449-1451
DOI: 10.1039/C0CC04532B, Communication

A synthetic approach to a fullerene-rich dendron and its linear polymer via ring-opening metathesis polymerization
Jonggi Kim, Myoung Hee Yun, Junghoon Lee, Jin Young Kim, Fred Wudl and Changduk Yang
Chem. Commun., 2011, Advance Article
DOI: 10.1039/C0CC05470D, Communication

Cationic and charge-neutral calcium tetrahydroborate complexes and their use in the controlled ring-opening polymerisation of rac-lactide
Michael G. Cushion and Philip Mountford
Chem. Commun., 2011, 47, 2276-2278
DOI: 10.1039/C0CC04348F, Communication
 

And also from our sister journal Chemical Science, a Perspective and an Edge Article for you to read:-

 Triggered structural and property changes in polymeric nanomaterials
Jason M. Spruell and Craig J. Hawker
Chem. Sci., 2011, 2, 18-26
 

Cylindrical micelles from the living crystallization-driven self-assembly of poly(lactide)-containing block copolymers
Nikos Petzetakis, Andrew P. Dove and Rachel K. O’Reilly
Chem. Sci., 2011, Advance Article
 
 

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Confining supramolecular soft materials

Confining soft materials in a small space has a dramatic effect on the formation of fibre networks and their resulting properties. 

 
 

Optical micrographs of the gels studied

Xiang Yang Liu and collaborators showed that the formation of fibre networks under volume confinement is independent of temperature and solute concentration. They need to do more studies to understand the mechanism but say that their work should help scientists design new soft functional materials on a micro-/nanometre scale.

Fancy delving some more into the results reported? Then why not download the communication* today and leave some comments on the blog below. Perhaps you have a question for the authors, or you could tell us what you found interesting about these results.

 *This communication will be free to access until the 25th March 2011.

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Potential route to a universal biosensing platform

A fully functional surface-tethered protein switch has been reported by US scientists. It is the first step towards a universal biosensor platform, they claim. 

Peter Searson, at John Hopkins University, Baltimore, and colleagues attached a protein switch with a maltose binding protein input domain and a beta-lactamase output domain to a gold surface. When maltose bound to the input domain, it switched on the beta-lactamase’s activity, which the team measured using the yellow-to-red colour change that took place as it hydrolysed the beta-lactam ring in nitrocefin.  Different input domains could be coupled to the same output domain, offering a potential route to a universal biosensing platform.

Read Surface-tethered protein switches, recently published as an Advance article in ChemComm.

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Approaching deadline for Emerging Investigator Lectureship nominations

Time is running out to nominate your colleagues for the ChemComm Emerging Investigator Lectureship 2011. Send your nominee’s details to the ChemComm Editorial Office by 28th February 2011.

And remember, to be eligible for the ChemComm Emerging Investigator Lectureship, the candidate should be within the first eight years of completing their PhD. Find out more….

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Nanoflowers for protein immobilisation and separation

It is the quest of many a materials scientist to form core-shell nanostructures by self-assembly, in order to generate materials with unique structures and functions. In this area, hierarchical nanoarchitectures assembled from nanoscale units have recently stimulated tremendous interest because these superstructures might avoid aggregation and maintain high specific surface areas. In addition, magnetic materials have received considerable interest,  due to their ability to selectively capture target objects from complex mixtures.

Ken Cham-Fai Leung and colleagues – based in Hong Kong and Hefei, China – have reported a facile synthesis of monodispersed microparticles composed of superparamagnetic Fe3O4 cores, a SiO2 shell and a hierarchical g-AlOOH periphery with Au nanoparticles, obtaining nanoflower structures resembling daisies. As proof of principle for their use as selective protein capturing agents, these nanoflowers were applied as absorbents to successfully remove bovine serum albumin from bovine blood.

To find out more download the ChemComm communication, which is free to access until 15th March 2011.

Start a discussion about this research by leaving comments below.

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Congratulations to Jean-François Nierengarten

Jean-François NierengartenWhat’s special about Gene delivery with polycationic fullerene hexakis-adducts?

Well, that’s the topic of Jean-François Nierengarten’s recent ChemComm communication, rated as ‘hot’ by the referees and free to access* until 15th March. It is also his 25th independent research article in ChemComm.

To celebrate this achievement, Professor Nierengarten has taken some time out from his research to speak to ChemComm about his career.

What inspired you to become a scientist?
As far as I remember, I was always fascinated by natural sciences and wildlife. I started to study biology at the University of Strasbourg (Université Louis Pasteur at that time) with the idea of becoming a zoologist to discover unknown animals in the Amazon rainforest or in other wild places in the world. On the way, I discovered chemistry thanks to a couple of outstanding teachers and definitively switched from biology to chemistry after I met Jean-Pierre Sauvage at the end of my first year of Master. Fortunately, after my Master, I had the chance to prepare my PhD under the guidance of Jean-Pierre, and thus to become a chemist.

What was your motivation behind the work described in your ChemComm article?
The work described in this paper is a part of our research program on the use of click chemistry for the post-functionalisation of fullerene hexa-adducts (Chem. Commun. 2008, 2450; 2010, 46, 3860 and 4160; 2011, 47, 1321). The initial driving force for this work was to apply the synthetic methodology developed in the group to the preparation of new molecules with specific properties. As very often happens, applications with our compounds rely on collaborations with colleagues having the appropriate expertise. Indeed, Jean-Serge Remy, a well-established scientist in the field of transfection and synthetic vectors, is a very good friend and discussing about science one Friday evening in a pub brought us to the idea of testing fullerene hexa-adducts as synthetic vectors. We thus prepared a series of hexa-substituted fullerene derivatives decorated with dendritic branches bearing peripheral ammonium groups. Jean-Serge and his co-workers could then show that polyplexes prepared from DNA and these globular polycationic fullerene derivatives exhibit remarkable gene delivery capabilities. This result was quite unexpected as a generally admitted rule for the design of gene delivery vectors is that compact globular polycations with an isotropic distribution of positive charges are not suitable candidates for such studies. The results reported in our ChemComm article show that this is indeed not the case.

Why did you choose ChemComm to publish your work?
For fast publication of our important findings, ChemComm is an obvious choice. Over the years, it has been always a pleasure to work with the RSC Journals in general and with ChemComm in particular. All the steps from the submission to the publication are very efficient and all is organized in a very professional way. Publishing our work in ChemComm is also the guarantee for high visibility. Finally, I am a supporter of European journals in general and strongly believe that the best of European chemistry should be reported in European journals. Having top quality journals in Europe is essential to give credit to the European chemical community.

Where do you see your research heading next?
In addition to their remarkable gene delivery capabilities, the fullerene hexa-adduct derivatives have also revealed a very low toxicity if any. The fullerene hexa-adduct core is therefore a particularly appealing 3D-scaffold for the development of new multifunctional bioactive molecules. Based on the versatile fullerene hexa-adduct building blocks already developed in our group (Chem. Commun. 2010, 46, 4160), the successive grafting of up to three different groups on the fullerene core can be efficiently achieved. We are currently working on a new generation of vectors bearing targeting subunits for specific gene delivery to selected cells and/or fluorescent probes to monitor their intracellular pathway by confocal microscopy.

What do enjoy doing in your spare time?
Spending time with Iwona, my wife, and our two kids, cooking, listening to music, travelling. I like also reading and playing the guitar but have less and less time for it!

What would you be if you weren’t a scientist?
Hopefully as happy as I am to be a scientist! I guess that it could be the case if I would be an ébéniste [cabinet maker]. During my childhood, I had a lot of fun making stuff from wood in the workshop of my godfather, a very talented ébéniste particularly gifted for marquetry. I could spend hours watching him applying pieces of veneer to form decorative patterns or pictures onto the commodes or the tables he was restoring.

Also of interest:
Less is more – multiscale modelling of self-assembling multivalency and its impact on DNA binding and gene delivery
Paola Posocco, Sabrina Pricl, Simon Jones, Anna Barnard and David K. Smith
Chem. Sci., 2010, 1, 393-404

*Access our free content any time, any place – register for an RSC Publishing personal account today

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Announcing the ChemComm Emerging Investigators issue 2012

Following the success of the inaugural ChemComm Emerging Investigators issue, we are delighted to announce the forthcoming 2012 Emerging Investigators issue. All interested parties should contact the ChemComm Editorial Office in the first instance.

This issue is dedicated to profiling the very best research from scientists in the early stages of their independent careers from across the chemical sciences. We hope to feature principal investigators whose work has the potential to influence future directions in science or result in new and exciting developments.

 

Also of interest:
ChemComm Emerging Investigator Lectureship:
Submit your nominations by 28th February 2011

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Enzyme logic biosensor for security surveillance

Scientists in the US have made a system that rapidly detects both explosives and nerve agents, providing a simple yes-no response. The technique could replace two time-consuming tests that are currently used to assess these threats.

Joseph Wang and colleagues from the University of California, San Diego, combined their expertise in threat detection and electrochemical biosensors with the biocomputing experience of Evgeny Katz from Clarkson University, Potsdam, NY. The team produced an enzyme-based logic gate with the ability to simultaneously detect both nitroaromatic explosives and organophosphate nerve agents.

Graphical abstract: High-fidelity determination of security threats via a Boolean biocatalytic cascade

See Chemistry World for the full news story and download the ChemComm article to find out more.

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