Archive for November, 2011

Simple aptasensor for detecting protein

Graphical abstract: Nicking enzyme based homogeneous aptasensors for amplification detection of proteinChinese scientists have made a simple and sensitive sensor for detecting proteins, which could lead to improved disease detection.

Huang-Hao Yang and colleagues at Fuzhou University used single-stranded nucleic acids known as aptamers to detect thrombin, an important protein involved in blood clotting. 

Although other aptasensors are known, they are more complex than this new sensor, says Yang. And the sensitivity here is three orders of magnitude higher than traditional homogeneous aptasensors. 

The improvement is thanks to a nicking enzyme, which Yang used instead of the more usual polymerase. A nicking enzyme recognises a specific sequence in double-stranded DNA. It then cleaves only one strand, leaving a nick in the DNA.   

The aptasensor is capable of detecting thrombin in real samples and could be expanded to other proteins simply by changing the aptamer sequence. 

To find out more about how it works, download Yang’s ChemComm communication.

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47 days until 100 issues…

….and did you know….?

47 is ChemComm‘s 2011 volume number, its second ever volume number.

The journal was not assigned a volume number when first published but we found that this caused problems for customers, in particular with online links to journal articles. Previous volumes published before 2010 have not been numbered retrospectively.

Articles published from issue 1, 2010, onwards should be cited as Chem. Commun., [year], [volume number], [page number].

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A model for the single chirality of life

Hot springThe boiling solutions in prebiotic hot springs could shed light on the emergence of a single chiral form of biomolecules in nature, say Spanish scientists.

Amino acids and sugars exist in living organisms exclusively in one of their two molecular chiral forms, which are mirror images of one another. The reason for this specificity has long puzzled scientists. Conditions on Earth when life first evolved in prebiotic times presumably favoured one form over the other, but the mechanism is so far unresolved.

‘We will most likely be unable to solve this fascinating conundrum, but experiments carried out under environmentally credible conditions may be important signposts to this end,’ says Cristóbal Viedma at the Universidad Complutense, Madrid. With this in mind, he and colleague Pedro Cintas have investigated crystallisation processes that lead to single chiral forms.

Read the full news story in Chemistry World and download Viedma’s ChemComm communication to find out the exact details.

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48 days until 100 issues…

….and did you know….?

ChemComm currently publishes 48 issues per year and has done so since 2005.

Find out more about the move to 100 issues >

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50 days until 100 issues…

….and did you know….? 

Graphical abstract: Percent buried volume for phosphine and N-heterocyclic carbene ligands: steric properties in organometallic chemistrySteven Nolan’s Feature article from 2010 has received 50 citations to date according to Web of ScienceSM (Thomson Reuters, 2011).

Read it: Percent buried volume for phosphine and N-heterocyclic carbene ligands: steric properties in organometallic chemistry

Are you interested in writing a Feature article? Contact the Editorial Office with your suggestion.

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Once, twice, three times a potential life saver – electrochemical immunoassay of cancer biomarkers

Early detection and diagnosis of cancer is essential to give sufferers an increased chance of overcoming the disease. The symptoms of liver cancer, in particular, are fairly innocuous – tumours are difficult to detect by physical examination and therefore the disease is not usually discovered until the later stages of development.

Dong Wang and co-workers have developed an electrochemical immunoassay which has the potential to improve the early detection rates of liver cancer by simultaneous detection of not one, not two, but three tumour markers. This simultaneous multianalyte immunoassay (SMIA) has a number of advantages over single-analyte immunoassay methods such as reduced overall cost per assay; improved efficiency; the potential to quantitatively measure the concentrations of proteins detected; as well as having a panel of biomarkers to confirm the diagnosis, lowering the likelihood of false-positive or false-negative results.

The team selected three electrochemical redox species with distinct voltammetric peaks to label three different antibodies as signal tags. These were then loaded onto carbon nanotubes coated with gold nanoparticles to improve the signal response.

Binding of the redox species labelled nanotube-antibody conjugates to the cancer biomarkers enables their electrochemical detection

By deciphering the voltammetric read-out, the team were able to establish successful binding events between the probes and the protein biomarkers, allowing simultaneous identification of the three analytes. Wang and his team then increased the sophistication of the immunoassay further by proving quantitative detection.

Dong Wang and co-workers appeared to have produced a robust SMIA with low detection limits that has the potential to save many lives. This efficient, gold nanoparticle-based technology could also be applied to other types of cancer or diseases – an immunoassay with a Midas touch.

To find out more, download the ChemComm article.

Posted on behalf of Sarah Brown, ChemComm web science writer.

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55 days until 100 issues…

….and did you know….?

Picture of Professor Jonathan L. Sessler55 is the age of ChemComm Associate Editor Jonathan Sessler (although don’t tell him I told you!).

Jonathan handles North American submissions in the areas of supramolecular and macrocyclic chemistry. He was one of the guest editors of this year’s Supramolecular Chemistry web theme, which is a superb collection of cutting edge contributions by international leaders in the field.

You can submit to Jonathan’s editorial office via our online submission system.

Read Jonathan’s latest ChemComm communication >

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Overcoming obstacles in labelling RNA

If you can’t beat them, join them… or rather incorporate, and then join them together. This is the approach adopted by Srivatsan and colleagues for conjugating labels to RNA, which they achieve by incorporating azide functionality into RNA nucleotides.

DNA oligonucleotides are routinely labelled by incorporating modified nucleosides into the desired DNA sequence and introducing the label post-synthesis; however, these standard methods offer low yields of the desired conjugate. Furthermore, modification of RNA is more challenging than DNA modification due to its inherent instability.

Copper catalysed alkyne–azide cycloadditions (CuAAC) and Staudinger ligations are the conjugation reactions du jour due to their high chemoselectivity and reported high yield. So, with this in mind, were Srivatsan and his team able to incorporate the required moieties into RNA oligonucleotides?

Yes! Using some extremely nice chemistry, they synthesised an azide-modified nucleotide and incorporated it into an oligoribonucleotide using in vivo transcription reactions in the presence of a series of promoter-template oligonucleotides. After rigorous testing and analysis of their modified nucleic acid sequence, click reactions were performed to yield biotinylated and fluorescent-labelled click products. They also showed that amine functionality can be introduced through Staudinger ligation.

Although azides are not usually found in nature, they are becoming more useful and versatile in the design of diagnostic and therapeutic biological probes as has been very elegantly demonstrated here.

Read more in Srivatsan’s ChemComm article

Also of interest: Synthetic DNA synthesises RNA by transcription: ‘click’ here for more

Posted on behalf of Sarah Brown, web science writer for ChemComm.

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Green hydrogenation of cyclic di-esters to diols

Hydrogenation of esters under mild conditions is difficult at best, however David Milstein and his team push the boundaries by hydrogenating biomass products, glycolide and lactide, to afford the corresponding 1,2-diols. Their synthesis, which utilises ruthenium pincer complex catalysts, offers an atom-economical, green alternative to existing methods for producing 1,2-diols, which currently rely on petroleum-derived ethylene and propylene feedstocks.

The team say that the cyclic di-esters can be selectively and efficiently hydrogenated under very mild conditions, whilst producing no waste, and even discovered that optically pure diols could be produced from chiral lactide.

Download the ChemComm article today to find out how Milstein and his team did this.

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Aromaticity web theme issue – welcoming submissions

We are delighted to announce a high-profile web themed issue on Aromaticity.

Guest editors: Nazario Martín (University Complutense of Madrid), Michael Hayley (University of Oregon) and Rik Tykwinski (University of Erlangen-Nuremberg)

This themed issue will consist of a series of invited Communications and Feature Articles covering work on all aspects of chemistry related with aromaticity – from new fundamental knowledge about aromaticity and theoretically interesting new arene structures to novel applications of aromatics and heteroaromatics which take advantage of their unique optical and electronic attributes.

The level of quality of this issue will be extremely high, and all manuscripts will undergo strict peer review. You are therefore encouraged to report work that you consider to be very important and conceptually significant. Please note that inclusion in the issue is subject to the discretion of the guest editors.

Publication of the peer-reviewed articles will occur without delay to ensure the timely dissemination of the work. The articles will then be assembled on the ChemComm website as a web-based thematic issue.

Submit your work before 31st May 2012. Please add “aromaticity” in the comments to the editor section.

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