ChemWeb Newsletter

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In The Alchemist this week, a new lead in lead detection, a blueprint for drug design, high-resolution NMR goes portable, nanoshells detect and destroy cancer cells, and finally nanoscale hard drive materials.

A new fluorescent probe for the toxic heavy metal lead has been developed by Chuan He and colleagues at University of Chicago and the Brookhaven National Laboratory in New York. The technique exploits the fact that lead is non-toxic to the microbe Ralstonia metallidurans. The microbe releases protective proteins in the presence of lead ions, which He and his colleagues have used to produce a quick and simple detector that responds to the presence of lead ions by producing a fluorescence signal. A "scout" protein, PbrR, made by R. metallidurans"keeps a lookout" for lead ions and switches on the microbe's lead-resistance gene. The researchers worked with the closely related protein PbrR691 instead of PbrR as it can be produced in large quantities more easily.

A new tool could point researchers to more effective pharmaceuticals and more environment friendly agrichemicals. The tool highlights possible molecular targets in genomic data, according to scientists at the Blueprint Initiative, a research program led by Christopher Hogue of Canada's Mount Sinai Hospital's Samuel Lunenfeld Research Institute. SMID-Genomes is a binding annotation and comparison tool that focuses on the interactions of small molecules and targets in the body involved with disease. It provides useful information that could shorten lead development times in the search for antimicrobial drugs. SMID-Genomes could also provide new insights into the interaction between small molecules and pest and weed proteins and so allow chemists to develop more specific and so safer pesticides and herbicides.

An invaluable new tool developed by German and US scientists could provide homeland security experts with a way to identify the chemical constituents of suspicious substances. The device, based on high-resolution NMR spectroscopy, is the first of its kind to be made portable and could become one of the principal tools for testing substances that might pose a security threat, such as suspect biological and chemical weapons and explosive materials. Researchers at the Institute for Technical Chemistry and Macromolecular Chemistry in Aachen, Germany, and Berkeley Lab in California developed the system so that they could obtain high resolution and so detailed analytical results without having to rely on the far from portable superconducting magnet NMR machines used in modern laboratories.

Nanotechnology could be added to the anticancer armoury thanks to research by Rice University scientists. Bioengineers Rebekah Drezek and Jennifer West are exploiting nanoscale particles, invented by colleague Naomi Halas in the 1990s, to simultaneously detect and destroy cancerous cells. According to the researchers, current molecular imaging approaches only detect cancer cells but do not offer a way to destroy them at the same time. Halas' metal "nanoshells" - tiny gold-coated silica spheres - scatter light in a particular way depending on their environment. The team has tuned the nanoshells so that when they come into contact with breast cancer cells they "light up". They suggest that the technique could be extended easily to target other cancer cell types or markers for other diseases.

Doping the semiconductor material gallium arsenide, GaAs, with manganese leads to a so-called dilute magnetic semiconductor. This new material could be used to shrink the size of the read heads used in hard drives and so boost capacity significantly without increasing the size of the disk, according to UK scientists. David Williams, the head of the Hitachi Laboratory at Cambridge University, and his colleagues discovered that manganese-doped GaAs exhibits tunneling anisotropic magnetoresistance (TAMR). Working with Bryan Gallagher at Nottingham University they built a mock-up read head just a few tens of nanometers across. Despite the small size of the device, the team was able to produce a large response. The researchers admit it is early days and there is a lot more work to be done in understanding the behaviour of the material.