Researchers in Europe have developed a hydrogen storage material based on porous magnesium borohydride that can safely adsorb large quantities of the gas via both a physical and a chemical mechanism. They used X-ray diffraction, infra-red and Raman spectroscopy to investigate this material.
Raman spectroscopy has become an increasingly useful tool in the geosciences partly because it is non-destructive and requires minimal sample preparation, but also because it can be carried out on site with various irreplaceable geological samples. Unfortunately, Raman can confuse, especially when substances such as haematite and disordered carbon materials are present in the same rocky sample.
- Space ice goes against the grain – Space ice made from a mixture of methanol and water expands under pressure, and shrinks when heated – the opposite behaviour to most solids. Dominic Fortes at University College London, UK, is interested in the internal structures of icy moons like Saturn’s Enceladus, which is thought to have an underground sea of water. But when measuring the properties of an ice-methanol system his findings were ‘entirely unexpected’ – the ice expanded with increasing pressure and shrank with heating.
- Thirty minute flu gene detector – Scientists in Japan have developed a portable influenza testing kit with better accuracy than current methods, which can give a result in 30 minutes. Scientists from the Tokyo Medical and Dental University and Sony Corporation made a nucleic acid amplification testing (NAT) device that not only gives information on the sample’s genetic make up to identify the flu pathogen type, but is also more than 90 per cent accurate. The device works by detecting the genes of the influenza virus pathogen – an organism that causes the disease – which gives information about the virus subtype and drug resistance.
- Enzyme logic biosensor for security surveillance – Scientists in the US have made a system that rapidly detects both explosives and nerve agents, providing a simple yes-no response. The technique could replace two time-consuming tests that are currently used to assess these threats. Joseph Wang and colleagues from the University of California, San Diego, combined their expertise in threat detection and electrochemical biosensors with the biocomputing experience of Evgeny Katz from Clarkson University, Potsdam, NY. The team produced an enzyme-based logic gate with the ability to simultaneously detect both nitroaromatic explosives and organophosphate nerve agents.
- Breakthrough for bacterial hydrogen production – Scientists in China have developed a device that can produce hydrogen from organic materials using bacteria at temperatures below 25 degrees Celsius.
- Fighting back against antibiotic resistant bacteria – Scientists in Japan have revealed how vancomycin dimers are effective against vancomycin-resistant bacteria. Vancomycin, a glycopeptide antibiotic, is used to treat bacterial infections in cases when other antibiotics are ineffective. However, the development of vancomycin resistant enterococci (VRE) and Staphylococcus aureus means that researchers are turning to different forms of vancomycin to improve its efficacy.
- Waking up to new possibilities in imaging – UK researchers have used a cage-like molecule to smuggle metal ions into cells, which could improve medical imaging.
- Acne-Fighting Boron Compounds, Anacor, and Medicis – Biopharmaceutical company Anacor have announced a partnership with Medicis to discover and develop small molecules to fight acne.
- Cancer breakthrough to prevent heart failure and increase survival rates – A breakthrough by scientists at Queen’s University Belfast could help reduce heart failure in cancer patients around the world, and ultimately increase survival rates.
- Omega 3′s — more evidence for their benefit – Omega-3 fatty acids –fats commonly found in fish oil – were shown several years ago to prevent retinopathy, a major form of blindness, in a mouse model of the disease. A follow-up study, from the same research team at Children’s Hospital Boston, now reveals exactly how omega-3′s provide protection, and provides reassurance that widely used COX-inhibiting drugs like aspirin and NSAIDs don’t negate their benefit. The findings, published in the February 9th issue of Science Translational Medicine, also suggest that omega-3′s may be beneficial in diabetes.
- Raman imaging gives new hope for cancer diagnosis – Combining two Raman spectroscopic imaging techniques could offer a valuable tool for future disease diagnosis, say UK scientists.
Another high yielding news day from Robert Slinn for Reactive Reports in his regular column: Slinn Pickings.
- Crystal clear hydrogen storage – Solid materials rich in hydrogen, such as ammonia borane could help solve the gas storage problem for vehicle fuel cells. Now, a crystal structure of an alternative material, DADB, offers new hope of a stable material that works at lower temperature (85 rather than 110 Celsius).
- Tannin test – At Christmas time, there's no need to be afraid…of testing your tannins, at least now that US researchers have developed a sensor capable of discriminating between the different tannins present in red wine.
- Forensic boost – The efforts of forensic investigators are often stymied by the diverse and complex nature of sample mixtures they must analyse but low analyte concentration is probably the most problematic issue they must address. Now, a US team has found a way to improve Raman spectroscopy for low-concentration analysis. Their approach could also improve medical diagnosis, drug/chemical development, and in national security.
The absolute configuration of a subtly chiral molecule has been determined using Raman optical activity and quantum mechanics. Werner Hug and his colleagues at the University of Fribourg, Switzerland, obtained the configuration of (R)-[2H1, 2H2, 2H3]-neopentane a molecule in which the central carbon is surrounded by four methyl groups bearing differing numbers of hydrogen isotopes.
For those who don’t know, a molecule is chiral (or handed) by definition if the left and right hand forms cannot be superimposed on to each other (a pair of hands, or gloves, for that matter are archetypally chiral (which comes from the Greek for hand).
The left and right-handed forms, or enantiomers, of (R)-[2H1, 2H2, 2H3]-neopentane are so similar that chemists had consigned this oddity to the lab shelf having given up any hope of distinguishing between its enantiomers. But not Hug. He and his colleagues were determined to push the limits of Raman spectroscopy to take this molecule back off the shelf and provide us with new insights into the nature of chirality.
Chirality itself lies at the heart of life on earth, but understanding the origin of the homochirality seen in nature remains a serious challenge, the new insights from Hug et al provides an important clue as to how isotopes may have played a role.
Hug et al publish details of their work in Nature.
Silicon chips and microelectromechanical systems (MEMS) that can be implanted in the human body will only be possible with a clearer understanding of the interactions between single-crystal silicon and human tissues and fluids, for example, formation of mineral apatite. This understanding will ultimately allow semiconductor devices to be interfaced with living tissues and so opens the door to implantable biosensors that can test indicators of disease or symptoms and then regulate the release of a drug. For instance, an implanted glucose sensor could be coupled to an insulin release system and so help diabetes sufferers control their blood sugar without pin-prick tests or the need to inject insulin.
Paul Chu and researchers in the Plasma Laboratory at the City University of Hong Kong have used plasma immersion ion implantation to improve the surface bioactivity of silicon and investigate the mechanism of apatite formation on silicon. In the October 18 issue of Applied Physics Letters, they reveal how micro-Raman and transmission electron microscopy results demonstrate the presence of a disordered silicon surface containing silicon-hydrogen bonds after hydrogen implantation. Immersing the sample in a simulated body fluid leads to an initial reaction of these Si-H bonds with water to form a negatively charged and functionalized surface, which leads to apatite formation. While previous researchers have recognized that a negatively charged surface is one essential component of interfacing semiconductor devices with living tissues, Chu’s work provides new insights into how this might be achieved on single-crystal silicon.
Chu told Reactive Reports how this pioneering work in making single-crystal silicon bioactive is important to biomedical microdevices such as MEMS and biosensors. With acceptable surface bioactivity and biocompatibility, silicon-based microdevices can be directly implanted into human bodies to detect various biological functions such as blood sugar, fluid pressure, cartilage abrasion, and so on. In addition to the osteo-compatibility of silicon, Chu’s research group is investigating the improvement of the blood compatibility of silicon-based materials such as silicon nitride using plasma treatments and their preliminary blood platelet activation results are very favorable.
According to Chu, a clearer understanding of the interactions between silicon surfaces and body tissues, as well as the development of a means to fabricate such surfaces, will expedite direct implantation of various types of silicon-based biosensors into the human body.
Appl Phys Lett, 2004, 85, 3623-3625; http://dx.doi.org/10.1063/1.1807009