ChemWeb Newsletter

Not a subscriber? Join now.July 19, 2005


This week in The Alchemist boosting X-ray sensors, starting up the hydrogen economy, light-conducting nanowires, displacing X-ray crystallography by NMR in protein studies, and finally using fuel cells to clean up waste water, generate electricity.

Better temperature control could pave the way to much more sensitive analytical devices according to researchers at the National Institute of Standards and Technology (NIST). Terrence Jach and colleagues have used improved temperature-sensing and control systems to detect X-rays across a very broad range of energies (6 keV or more), with pinpoint energy resolution (an uncertainty of only 2 eV). They built on earlier work to develop a new, improved microcalorimeter X-ray detector. The device acts as a quantum-level, transition edge sensor (TES) and can be held at low temperature for hours to detect trace levels of analytes.

A hi-tech start-up company hopes to bring the hydrogen economy closer by developing a new method for production of this key gas. US company Signa stumbled across the hydrogen-production process while trying to develop an air freshener. The company's researchers mixed sodium metal with silica gel or a crystalline silicon blend to create a powder that essentially strips electrons from the sodium atoms and traps them. When water is added to the sodium in the gel blend a much calmer hydrogen-producing reaction occurs than would otherwise happen. Signa says the harvested electrons can also be tapped off for electricity but more importantly almost a tenth of a kilogram of the powder gets released as hydrogen with little energy loss as heat.

A new technique uses phospholipid membranes to dope cadmium chloride nanowires that can "conduct" light. Horst Vogel of ETH Lausanne, Switzerland, and colleagues have developed a novel approach to one-dimensional nanoscopic wires that could become important building blocks for future miniature opto-electronic components. The Swiss team used lipid membranes as "molds" to make high yields of cadmium chloride wires, which act as nanoscopic fiber optics. They have synthesized nanowires up to 170 micrometers long and just 100 nanometers in diameter formed as single continuous crystals capable of channeling photons.

Genomics and protein studies could receive a spectroscopic push to fast-forward thanks to a University of Buffalo scientist who has developed a high-speed, high-throughput variation on NMR spectroscopy that can outstrip X-ray crystallography. Thomas Szyperski and structural genomics colleagues have demonstrated that they could determine the structures of eight proteins in just 10-20 days per protein. Conventional X-ray crystal structures take several months per protein and are only available if the protein can be crystallized. Their technique, known as GFT-NMR (G-matrix Fourier Transform NMR), can solve very disparate protein structures, including membrane proteins the key to structural genomics and a highly prized target in rational drug design.

US researchers have developed a fuel cell that not only generates electricity in an environment friendly way but also treats waste water. Lars Angenent of Washington University St Louis and his team have developed a microbial fuel cell that works differently from other fuel cells of its type. Angenent uses a carbon-based foam with a large pore size on which biofilm grows, allowing him to connect two electrodes in the anode and cathode chambers with a conductive wire. The fuel cell is doing basically the same thing as a standard hydrogen fuel cell except that the bacteria on the anode act as the catalyst instead of platinum. Angenent says that producing energy from wastewater should be a high international priority because of population growth and worldwide depletion of energy resources.