Author Archive

To expand or not to expand?

Two dumbbell-shaped polymorphs possess similar packing arrangements, but one shows anomalously anisotropic thermal expansion while the other does not.

Leonard J. Barbour and his team from the University of Stellenbosch, in South Africa and a co-worker from the Polish Academy of Sciences, have investigated these polymorphs further and discovered that by adjusting the molecular stacking angle by approximately 10° effectively disables the molecules’ ability to undergo thermal expansion.

Fancy expanding your knowledge? Then why not download the ChemComm communication today and read all about the teams research results? This article is free to access until Friday 3rd June.

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Anticancer drug found to cause zinc deficiency

Cisplatin is responsible for abnormally low zinc levels in patients undergoing chemotherapy, say scientists in China and the UK.

Platinum-based compounds, like cisplatin, are the most widely used anticancer drugs in medicine. Research shows that up to 98 per cent of cisplatin binds to blood plasma proteins, particularly albumin. Until now, little has been known about the specific binding sites for platinum on albumin. ‘Since albumin plays a major role in cisplatin metabolism, a better understanding of its interactions with albumin should lead to more effective use of the drug and avoidance or control of side effects,’ says Peter Sadler from the University of Warwick, in the UK.

Cisplatin (structure in the middle) reacts with recombinant human albumin (rHA) (blue and green structures) to create a cisplatin-rHA adduct, which displaces zinc, causing a deficiency

Together with Fuyi Wang’s team from the Chinese Academy of Sciences in Beijing, Sadler used mass spectroscopy techniques to reveal that cisplatin reacts with recombinant human albumin (rHA) to create a cisplatin-rHA adduct. The platinum occupies zinc binding sites on the albumin, displacing the zinc, which causes hypozincemia (lack of zinc for metabolic processes) and hyperzincuria (increased zinc in urine). 

 

 Would you like to know more? Then read the full story on the Chemistry World website and download the ChemComm communication.

 

 

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Meet our author… Martin Blaber

Martin Blaber, an enthusiastic surface chemist, working as a post-doctoral researcher for Professor Schatz at Northwestern University, in the US, takes some time away from his research to speak with us… 

Blaber’s recent communication, published in ChemComm, reports some of the challenges that come with using nanosphere dimers for surface enhanced ramana spectroscopy (SERS) at long wavelengths: Extending SERS into the infrared with gold nanosphere dimers 

 

Martin Blaber

 What initially inspired you to become a scientist? 

It was definitely nanotechnology.  While at at high school, I got very excited about the possibility of nanobots! Not the malevolent world destroyers, but rather the constructors of sky scrapers and converters of refuse into sports cars etc. The possibilities were endless! I enrolled in a BSc majoring in nanotechnology. After learning that bacteriophages could be programmed to build battery terminals and other wonderful things, I decided that micromachines were best left to biologists and I swapped nanobots for nanoplasmonics, eventually completing a PhD studying alternative materials for nanoplasmonic systems. 

What was your motivation behind the work described in your ChemComm article? 

Electric Field Enhancement!
SERS can be used to detect tiny amounts of many industrially, scientifically and socially important chemicals. SERS is used to identify counterfeit currency, detect chemical warfare agents and help art historians determine pigments for preservation projects. A major component of the enhancement in SERS is due to the localisation of electric fields around metallic nanoparticles when they are irradiated with light. This phenomenon is known as surface plasmon resonance. Our work involved trying to maximise the electric field enhancement around a dimer of gold nanospheres so that molecules attached to the surface of the spheres would have the largest possible surface enhanced Raman signal. This work grew out of previous studies noting that SERS intensity increased with increasing surface plasmon resonance wavelength. If the maximum field enhancement reaches approximately 1012, single molecules should be readily detectable. It turns out that in our case, the field enhancement follows a trend that causes the enhancement to “max out” for laser wavelengths of around 700 nm, limiting the average field enhancement to 108.
 

  

Why did you choose ChemComm to publish your work? 

ChemComm recently published a special issue dedicated to SERS* that I thought would help broaden both the readership and impact of our article. 

Where do you see your research heading next? 

In this article we investigated a very specific system to determine how the field enhancement scales with surface plasmon resonance wavelength. Trends like this are geometry dependent, and there is such a multitude of other nanoparticle geometries that are readily fabricated via wet chemistry that the possibilities are essentially endless! 

What do enjoy doing in your spare time?
Cycling, listening to music, watching movies, spending time with family and friends.
 

If you could not be a scientist, but could be anything else, what would you be?
I thought I’d like to be an M.D. but clumsiness and scalpels don’t go well together, so I’d settle for being an astronaut.
 

  

*ChemComm recently published a SERS web-themed issue, guest edited by Duncan Graham, Zhongqun Tian and Richard Van Duyne. Interested in SERS? Then take a look at our online collection of articles today! 

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A touch of gold for cycloisomerisation reaction

Gold-catalysed cycloisomerisation of alkynyl hydroxyallyl tosylamides has led to the concise synthesis of oxaazatricyclic compounds and revealed an interesting skeleton structure, say scientists in South Korea.

Research groups across the globe have reported cycloisomerisation reactions of alkynyl allyl alcohols (AAAs) with rhodium, iridium, palladium and nickel catalysts. Naturally, research groups have been led into investigating the use of gold catalysts, providing plausible reaction pathways for these reactions. 

Young Keun Chung and colleagues from Seoul National University and Sangmyung University, used subtly different reaction conditions than have been previously reported, resulting in an usual oxaazatricyclic skeleton compound being uncovered for the first time, as shown in the X-ray structure obtained below.

X-ray structure of cycloisomerised oxaazatricyclic compound

To find out more about this unexpected result and the reaction conditions used, why not download the communication today? The results have been published in ChemComm and will be freely available until the 13th May 2011!

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Unique sorption properties for isomeric frameworks

Two porous supramolecular isomeric frameworks have shown unique sorption properties, say a collaboration of Chinese and Japanese scientists. 

One framework shows temperature dependent and selective sorption of CO2, while the other framework shows gas uptake capacity for CO2, N2, H2 and CH4 at low temperature and selective sorption of CO2 over N2 around room temperature. Wei-Yin Sun and colleagues believe that the results provide useful guidance for improving metal organic framework (MOF) designs for gas storage and separation techniques. 

 

Two porous supramolecular isomeric frameworks show unique sorption properties

Find out more, by reading the research results published in ChemComm. This article has been made free to access until the 13th May 2011, so why not download the communication today? 

  

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All systems GO for biosensing platform

Graphene oxide (GO) plays a crucial role in a new, sensitive biosensing platform, acting as an efficient quencher for upconversion nanophosphors, say scientists in China. 

Zhengping Li, Chenghui Liu and colleagues from Hebei University, have constructed a sensitive and practical biosensing platform by combining lanthanide-doped upconversion nanoparticles (UCNPs) with single-stranded DNA (ssDNA). Upon the addition of water soluble GO the upconversion fluorescence is quenched, effectively turning ‘off’ the fluorescence signal. To test the platforms sensing ability and performance, the team introduced adenosine triphosphate (ATP) resulting in the formation of an aptamer-ATP complex, preventing the UCNPs interacting with the GO surface and thus decreasing the quenching efficiency, resulting in the fluorescence staying ‘on’. Other phosphates were tested, like guanosine triphosphate (GTP), cytidine triphosphate (CTP) and uridine triphosphate (UTP) but no dramatic fluorescence enhancement was observed, so this indicates that the aptamer system is specific to ATP alone.

Upconversion FRET between ssDNA-UCNPs and GO for ATP sensing

Interestingly, the team also tested the biosensing platform with mercury ions, which caused the ssDNA to form double-stranded DNA (dsDNA), preventing the UCNPs interacting with the GO surface and again resulted in enhanced fluorescence emission. Other similar cations were tested in comparison, but the biosensor only shows selectivity for mercury ions, providing a good indication into the high specificity that this biosensing platform has, in addition to its future potential for uses in clinical diagnostic and biosensing applications.

Fancy finding out more? Then why not download the communication today – published in ChemComm, the article has been made free to access until the 13th May 2011.

Please also let us know what you think to this research by blogging some comments below.

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Reusable template for pattern transfer

Contact area lithography has been used for directly patterning and transferring self-assembled monolayers (SAMs) onto silicon-based substrates.

 

One-step patterning & transfer of SAMs on SiO2/Si substrates

Hyunjung Shin and colleagues from Kookmin University, in South Korea used a patterned (hard) silicon oxide template and placed it on substrates of interest, introducing a small amount of water in the process.
After drying off the water, the non-contacted areas served directly as growth sites of OTS-SAMs by simple solution deposition. The hard template was then detached from the substrate and the patterns of SAMs were obtained.

In principal, the hard template is cleansable by simple chemical etching without causing any damage. It is also 100% recyclable and can be reused up to ~50 times.

Fancy finding out more about this technique? Then why not download the communication today, which has been published in ChemComm and will be free to access until the 13th May 2011.

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Beads clicking into place

Scientists in Belgium have designed a microfluidic setup that manufactures thiol and yne beads, which can then undergo several click-type reactions.

Filip Du Prez and his team at Ghent University demonstrated the yne beads reacting with an azide or two thiols, whereas the thiol beads were tested using nine different reaction conditions. The thiol–isocyanate reaction was seen to be the fastest, being closely followed by the thiol–norbornene reaction.

 

Light Microscopy image of monodisperse thiol beads (left image). Fluorescent yne beads after clicking with coumarin-derivative (right image).

Du Prez believes that this discovery may help to guide researchers, especially in the field of solid phase synthesis, to choose the most suitable ligation reaction according to their needs since many of the conjugations studied are part of the click family. 

Published in ChemComm this communication will be freely available until the 13th May 2011. Why not download the communication today and find out more about the beads and their clicking abilities?

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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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