News in Brief
Venus de Micro
This image shows an array of 16 small torsos, modelled on the famous Venus de Milo, produced simultaneously by a 16 beam two-photon polymerisation (2PP) system. 2PP uses femtosecond laser pulses to polymerise a photosensitive material.
But the system doesn't just produce tiny sculptures. Researchers from the Laser Zentrum Hannover, Germany, and the Joint Department of Biomedical Engineering at the University of North Carolina at Chapel Hill and North Carolina State University, US, have modified 2PP to create multiple structures at once and so speed up the fabrication of tissue scaffolds.
Publishing in Biomedical Optics Express (DOI: 10.1364/BOE.2.003167), the group show how using a computer controlled hologram can split the 2PP laser into 16. However, the team have so far only used the multiple beams to create identical structures. The next step is to make one large, complex structure, but that is a more complicated task.
Clicking your way to synthetic antibody therapies
US scientists have clicked together synthetic antibodies using the enzymes they want to target as a template. These synthetic antibodies can then be used, in turn, to bind to the enzyme templates they were cast from, which could also open up a whole new field of therapeutic molecules.
The team adapted click chemistry to create anchor peptides for an enzyme, in this case the kinase Akt1, which has been implicated in many different forms of cancer. Akt1 was incubated with a library of solid phase pentamers with an N -terminal azido-amino acid, and then with another pentamer library. The ligands that bind to domains on Akt1 are then close enough for an in situ click reaction to bind them together, making best fit capture agents. The work is published in the Journal of the American Chemical Society (DOI: 10.1021/ja2064389).
Herbert Hauptman, 1917-2011
Herbert Hauptman, who won the Nobel prize in chemistry in 1985 for his work on how to determine molecular structures using x-ray crystallography, has died.
Hauptman, a mathematician, served in the US Navy during the second world war, before joining the Naval Research Laboratory in Washington, DC, and completing his PhD from the University of Maryland in 1955. Hauptman left the naval facility in 1970 and joined the Medical Foundation of Buffalo as head of the biophysics lab. The institute was later renamed the Hauptman-Woodward Medical Research Institute and Hauptman worked there into his 90s, as research director and later president.
Hauptman shared his Nobel prize with Jerome Karle, with whom he worked to develop mathematical equations to interpret the x-ray diffraction patterns from crystals. The technique was controversial at the time of the work (in the early 1950s) but has become indispensible to modern chemistry.
Hauptman is survived by his wife, Edith, and two daughters.
Faster synthesis of 18F imaging agent
A palladium-containing fluorination reagent can be used to quickly synthesise aromatic molecules labelled with 18F, a positron emitter used in molecular imaging, say US chemists. The unstable isotope, with a half life of just 110 minutes, is generated by proton bombardment of water enriched with 18O and needs to be used in clinical settings as fast as possible.
Positron emission tomography (PET) is a non-invasive 3D imaging technology used in biomedicine and diagnostics. Incorporating a radionuclide tracer into a molecule allows tissues to be imaged by PET.
In work published in Science (DOI:10.1126/science.1212625), the team used an organometallic complex that is an electrophilic fluorination reagent to produce the required product and demonstrated that they can produce 18F-labelled small molecules within five minutes, with the insertion of the radionuclide occurring in the final stages of the process. This ensures a high level of 18F radioactivity in the molecule immediately prior to clinical use.
Do carbyne radicals exist in water?
Carbyne radicals - carbon atoms with one bond and three non-bonding electrons - could survive in aqueous solutions after being ejected from metal complexes, claim researchers in Israel. The results, published in Angewandte Chemie, International Edition (DOI: 10.1002/anie.201103652) could have a profound influence on our understanding of metal-carbon bonding.
The team has been trying to get to the bottom of how metal carbyne clusters (complexes with carbyne ligands that bridge three metal atoms) couple together to form alkynes for over 30 years. The latest batch of experiments points to the unlikely conclusion that, in water, the complexes release free carbynes into solution. These can apparently then react in a multitude of ways to produce a host of different organic molecules, and even survive long enough to react with each other and form alkynes.
However, the conclusions are unexpected, and some researchers remain sceptical. The team is now working on more experiments to confirm and probe the findings in more detail.
Shared services centre slammed
A report from the National Audit Office (NAO) claims that the Shared Services Centre, designed to save money by combining the back-office functions of the UK's seven research councils, was embarked upon without proper planning.
According to the report, there is a risk that the councils will not recover their investment after the project came in 15 months late and £51 million over budget. The NAO also criticise the Department for Business Innovation and Skills for not stepping in when problems became apparent. However, the report concludes that savings could still be made.
In a statement, Research Councils UK said that they are already putting into place most of NAO's recommendations in an attempt to get the centre back on track.
Knots can be (at least partly) defined by the number of times (and ways) the strand crosses itself along its length. The simplest knot is a trefoil, which has three crossing points and was conquered at the molecular level last year (See Chemistry World, March 2010, p28).
Publishing in Nature Chemistry (DOI: 10.1038/nchem.1193), researchers from the University of Edinburgh, UK, have now upped the ante to a pentafoil knot, with five crossings. One of the biggest differences in strategy between the trefoil and pentafoil knots is a move away from starting with a single long molecular strand.
The team found it just too difficult to encourage such a molecule to entwine around itself correctly. Instead, they assembled five shorter strands around a central chloride ion template, lashed them together with iron ions to cement the shape of the crossing points, then closed the knot by covalently joining the ends of the strands together.
Boosting batteries with small holes
According to US scientists, publishing in Advanced Energy Materials (2011, 1 (6), 1079), lithium ion batteries could soon charge more quickly and hold a much higher charge. The team have made a new graphene-silicon composite cathode with carbon vacancies in the graphene sheets and silicon nanoparticles sandwiched between the sheets.
These changes maximise the amount of lithium ions that can be held in the electrode (equating to the charge the battery can store) and allow the lithium ions to diffuse through the electrode more easily, decreasing the charging time.
In the paper, the team says that the new material gives the battery a hitherto unachievable combination of power capability and storage capacity, and the preparation method can be easily scaled up. They expect that batteries using this material could be in the shops within five years.