ChemWeb Newsletter

Not a subscriber? Join now.November 14, 2006


This week in the Alchemist, Platinum gets all frothy, man... we discover that European are faking it down on the farm, and regulating a man's estrogen levels could reverse prostate disease and cancer. Also this week how to split a light beam, ever so slightly, with lemon juice and squeezing metal ions into bigger buckyballs could lead to improved solar panels and better medical scanning.

Liposomes can act as templates for the formation of hollow platinum nanospheres, according to John Shelnutt of the University of Georgia, Athens. Such particles could have diverse biomedical, catalytic, and optical applications. Working with colleagues at the Sandia National Laboratories and the University of New Mexico in Albuquerque, Shelnutt and Yujiang Song have developed a novel strategy for producing relatively large platinum cages based on continuous, branched (dendritic) platinum sheets. The approach exploits the ability of liposomes modified with a light-activated tin-porphyrin catalyst to induce a self-assembly process. In platinum solution under light, the liposomes initiate construction of platinum clusters, which then catalyze the formation of branching structures that then aggregate to form a platinum froth. The liposomes can then be removed and to leave behind platinum spheres up to 200 nanometers in diameter.

At least a fifth of all pesticides sold across the European Union is fake, according to a report in the UK's Society of Chemical Industry publication Chemistry & Industry. The problem could endanger food safety and human health in an industry worth 7.5 billion euros (almost $10b). Counterfeit products range from illegal copies of patented products to low-quality fakes. Roger Doig, President of the European Crop Protection Association, told the journal the problem is getting worse each year. "Clearly there are risks when products that have not been properly studied or evaluated are being brought on to the market," he said. Recent incidents highlight the extent of the problem. In February this year, a counterfeit herbicide used in Italy was found to contain quantities of a hazardous insecticide while in 2004, hundreds of hectares of wheat were wiped out in France, Italy and Spain because fake herbicide was used. The ECPA recently launched a pan-European Anti-Counterfeit Programme, in an effort to get governments and regulators to use their powers to enforce regulatory policies.

Estrogenic hormones are usually considered the preserve of the female endocrine system, but recent research suggests a much bigger role in male physiology than previously known. Now, a team from Monash University, Melbourne, Australia, have demonstrated that an estrogen-regulating drug aimed at men could reverse the progression of prostate cancer and prostate swelling (benign prostate hyperplasia. The team presented its findings to the Society for Endocrinology conference in London on November 6. Gail Risbridger and her colleagues have tested compounds that selectively activate one but not both estrogen receptors in men. They can thus turn on one receptor (oestrogen receptor alpha) without affecting its beta counterpart. The alpha receptor has been linked to malignancy whereas activation of the beta receptor appears to have beneficial effects on prostate disease.

A two centuries old prediction has at last been confirmed by Ambarish Ghosh and Peer Fischer of the Rowland Institute at Harvard University. They have demonstrated that a beam of light can be split in two using a chiral liquid. The phenomenon was first suggested by French physicist Augustin Fresnel, famed for his eponymous lens, in the early 19th century. Fresnel studied optically active materials and realized that linearly polarized light might be regarded as equal parts right- and left-circularly polarized light. He suggested that this might allow a single beam to be split into its left and right components with an optically active liquid. Gosh and Fischer tested the assumption using limonene oil and a high resolution camera to detect a divergence of just a few ten thousandths of a degree or arc. Ghosh and Fischer point out that the beam splitting effect could be used to sensitively analyze the chirality of unknown substances using only a tiny sample.

A Virginia-based startup called Luna nanoWorks will soon commercialize an outsized buckyball ([80]fullerene) that can trap a three-metal nitride cluster within. The material, first synthesized serendipitously by Harry Dorn at Virginia Tech, in Blacksburg, has some rather unusual electrical, optical and magnetic properties. Luna nanoWorks anticipates that the compound will be useful in novel devices such as high-efficiency solar cells as well as in medical scanning as a magnetic resonance imaging (MRI) contrast agent. The large interior of this larger fullerene cage means it can hold three gadolinium ions at once and so could work in the next generation of high-power MRI where conventional agents are inadequate.