September 2006



A gel that shrinks in the heat and swells in the cold has been used as a valve in a microchip drug delivery system by Japanese researchers.

Stimuli-responsive gels have previously been incorporated into microchips, but their manufacture often involves several stages and specialist equipment. The approach of Ryo Yoshida and colleagues at the University of Tokyo, Japan, offers a simple alternative fabrication route using standard laboratory apparatus.

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Researchers in Europe and the US say they are the first to use deliberately a bifluoride building block to make a three-dimensional coordination polymer.

The structure, made by Jamie Manson at the Eastern Washington University, Cheney, US, and colleagues, contains copper ions bound to pyrazine molecules in a planar square.  Bifluoride ions (HF2) sit above and below the copper ions. Each pyrazine molecule can bond to one copper ion at each end, to give a potentially infinite copper–pyrazine plane. Bifluoride ions act as bridges between the planes.

The structure is very thermally stable (up to 200 ºC) due to the exceptional strength of the hydrogen bonds within it – bifluoride contains the strongest known hydrogen bond.

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There’s a handy roundup of chemistry blogs over at the Sceptical Chymist for your blogrolls … which conveniently allows me to experiment with using trackbacks for the first time (hey, I’m pretty new to this!).

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A study into the potentially damaging mental health effects of organophosphates (OPs) may be brought to a premature close by the government’s Department for Environment, Food and Rural Affairs (Defra), after a medical and scientific review panel (MSP) questioned its research protocol.

Farmers use OPs in sheep dips to counter sheep scab, a disease caused by a parasitic mite. Between 1976 and 1992 sheep farmers were obliged to use OPs, but since then their use has been optional. Critics say that farmers exposed to OPs, which are potent nerve toxins, can suffer from chronic fatigue syndrome, muscular paralysis, and a collection of symptoms termed ‘dipper’s flu’.

Sarah Mackenzie-Ross from University College London (UCL), UK, is leading the threatened study which was commissioned by Defra four years ago. The team say that the study is the first to combine a thorough psychological assessment of farmers with blood tests to assess how effectively each individual can metabolise OPs.

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Making 55 000 nanoscale images of Thomas Jefferson might sound like an eccentric art project, but this is the first demonstration of a new technique that harnesses the power of thousands of nanoscale pens working in synchrony.

Chad Mirkin and his colleagues at Northwestern University in Illinois, US, drew their Jeffersons using a microscopic pen that deposits dots of a molecular ‘ink’ onto a gold substrate in a controlled, aligned pattern. They have called the technique parallel dip-pen nanolithography (DPN).

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A recent ban on French oysters has highlighted a controversy about how food should be tested for marine biotoxins.

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Polymer capsules that can simultaneously deliver drug molecules and DNA into a cell could boost the power of cancer treatments, scientists say.

The capsules are biodegradable nanoparticles that have an internal hydrophobic cavity that can hold drug compounds. In contrast, the outer shell of the capsule is positively charged and can bind DNA or RNA.

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Since their widely reported invention, the development of fullerene-wheeled nanocars hasn’t stood still.

In 2005, James Tour and colleagues at Rice University, Texas, US, made headlines when they reported nanocars with fullerenes for wheels and a chassis of fused aromatic rings.1 The vehicles, three nanometres in size, rolled across gold surfaces observed by scanning tunnelling microscopy.

Tour made a quintillion (a billion times a billion) vehicles in a single experiment, or as he put it, ‘more nanocars than the number of automobiles made in the history of the world.’ The cars were powered by externally-applied electric fields.

Now Tour and colleagues have reviewed their recent progress in making a range of nanovehicles

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A microfluidic imaging method that could be incorporated into a hand-held microscope may be a significant step forward for medicine in the developing world.

Changhuei Yang, Xin Heng and colleagues from the California Institute of Technology, Pasadena, US, have developed a technique known as optofluidic microscopy (OFM), which they claim could help doctors to diagnose malaria more quickly.

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Swiss scientists have revealed the fingerprint of lipase enzymes.

Jean-Louis Reymond and Johann Grognux at the University of Berne have produced a microarray system that can be used to create a unique map of an enzyme’s activity. ‘We usually think of [enzyme] activity in terms of one substrate or maybe two. With fingerprinting we want to provide comparative data on many different substrates,’ explained Reymond.

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