Short items, April 2012

Quick(lime) HIV detection


The new device can detect HIV in the field at an early stage of infection

US researchers have developed a rapid testing kit for HIV, which uses nothing more sophisticated than quicklime to power it. The device, which relies on heat generated from hydration of calcium oxide, should be useful in situations where there is no electricity, such as in rural areas in developing countries.

HIV antibody tests can be performed away from the lab but they lack the ability to detect recent infection, while tests that detect nucleic acids from HIV can confirm the presence of the virus much sooner after infection. However, until now, these tests have required costly equipment and needed to be carried out in a laboratory.

The new device uses the exothermic reaction between quicklime and water to perform isothermic amplification of the viral DNA with a fluorescent label, allowing for visual identification of infection. Although the heating device has been previously described, it has never been used for HIV detection before, and could prove a cheap and simple method for point of care HIV diagnosis, say the researchers. The work is published in PLoS ONE (DOI: 10.1371/journal.pone.0031432).

Japan merges science centres to cut costs

The Japanese government is consolidating five of its most prestigious scientific agencies - the Japan Science and Technology Agency (JST), RIKEN, the National Institute for Materials Science, the Japan Agency for Marine-Earth Science and Technology and the National Research Institute for Earth Science and Disaster Prevention - into one organisation under the control of the Ministry of Education, Culture, Sports, Science and Technology (MEXT). The cost cutting measures will also see the number of independent administrative corporations (IACs) - former national research institutes and governmental agencies - cut from 102 to 65 by merging those under the same ministry. The reorganisation comes as Japan searches for ways to reduce its national debt.

Metal ions link up proteins

Inorganic chemists, led by Akif Tezcan, at the University of California, San Diego, US, have assembled proteins into sheets, tubes, chains and more, by using metal ions to link separate protein molecules together. The work, published in Nature Chemistry (DOI: 10.1038/nchem.1290), creates complex and flexible structures that can be tuned by varying metal concentration and pH, much like viral capsids. 

This work, which is the first reported method of forming responsive, complex protein assemblies - although many others are rumoured to be in the pipeline - uses two or three metal coordination sites, engineered onto protein surfaces. When zinc ions are added, depending on the conditions, different three-dimensional structures are created.

Graphene stymies body’s efforts to expel it

Graphene nanoplatelets can penetrate deeper into the lungs than their size would suggest, say UK researchers. And once there, the body’s natural defences cannot deal with them effectively. Chronic exposure could therefore lead to inflammation and disease in a similar way to asbestos fibres. 

In ACS Nano (DOI: 10.1021/nn204229f), Ken Donaldson and colleagues at the University of Edinburgh, UK, report how graphene dust (as it is often supplied) inhaled from a solution as it evaporates penetrated deep into the lungs of mice. The group found that although the particles look large, because they are flat and plate-like, the unusual aerodynamic properties of the platelets mean that they can get as deep into the lungs as spherical particles a tenth of the diameter. 

Donaldson’s team also found that, once the graphene platelets lodge in delicate parts of the lungs, the immune response was ineffective at removing them. This led to inflammation and potentially has more serious implications for long term exposure. However, the risk is only likely to be prominent for people working with these materials over long periods, says Donaldson, and normal protective equipment should filter out the platelets. 

Leak suggests Dow hired firm to follow Bhopal activists

Dow Chemical hired US intelligence companies to monitor the activities of protestors belonging to groups demanding justice for victims of the Bhopal disaster in India, according to emails published by whistleblower website WikiLeaks. The methyl isocyanate gas leak from the Bhopal pesticide plant in 1984 killed thousands and injured over half a million and victims are still pressing for further compensation from the US chemical giant.  

The correspondence was obtained when the Texas-headquartered global intelligence company Stratfor was hacked in December. They are among over five million emails that WikiLeaks began publishing on 27 February. The emails, dated between July 2004 and late December 2011, suggest that Dow hired Stratfor and Michigan-based Allis Information Management to gather news stories pertaining to the Bhopal incident and track the activities - including travel - of activists seeking compensation from Dow for the disaster. 

Paper robots

The latest robot from the George Whitesides’ lab at Harvard University, US, is simply made of paper and silicone rubber and driven by air. But despite being made from such a simple material, the inexpensive robots can lift objects up to 120 times their own weight with a gentle, even pressure. 

The robots, which are reported in Advanced Functional Materials (DOI: 10.1002/adfm.201102978), are folded in just the right way so that when air is pumped into the silicone air channels, the robot expands in a predetermined fashion - straight up or with kinks and curves. 

This is the latest ’squishy robot’ from Whitesides, who has previously made air driven robots from just silicone rubber. 

Sherry Rowland dies at 84


CFC pioneer Sherry Rowland, 1927-2012

Atmospheric chemist Frank Sherwood Rowland died on Saturday 10 March, aged 84, from complications related to Parkinson’s disease. He was best known for his work with postdoc Mario Molina that showed that chlorofluorocarbons (CFCs) can destroy ozone. Rowland campaigned for a ban of the then widely used CFCs.

In 1987, some years after the original discovery of the action of CFCs, and following evidence that their use had led to the formation of a hole in the ozone layer above the Antarctic, CFCs were finally banned from sale. ’His publicising the adverse effects of the release of CFCs in the 1970s did not endear him to industry, but eventually led to his Nobel prize, which he shared with Mario Molina and Paul Crutzen,’ said RSC president David Phillips in a statement. ’In the early stages of his research on CFCs, he and his students used to travel the world taking air samples - I have some photographs of him doing just that in the grounds of the Vatican in Rome in 1982 where he and I were taking part in a discussion meeting of the Pontifical Academy of Sciences.’

Rowland did not slow up after his success with CFCs and, as well as continuing an active research career, he campaigned against other harmful air pollutants. In 2009, Rowland joined with other Nobel laureates to urge US president Barack Obama to increase funding for energy research and development. ’The most important molecule involved in global warming is carbon dioxide,’ Rowland told Chemistry World  at the time. ’What we are looking for is energy solutions that are advanced and that can last for centuries or more, and chemists will need to be working on these things for an extended period.’

Rowland, known as Sherry, was born on 28 June 1927 in Delaware, Ohio. After receiving his PhD from the University of Chicago, while working with physical chemist Willard Libby, Rowland worked as a nuclear chemist and was a founding faculty member of the University of California, Irvine campus, which was to be his home from 1964. ’He was a major force in atmospheric chemistry and, along with his family, he will be greatly missed by all of his colleagues too,’ Phillips said.

Hungarian red mud contains toxic vanadium

The red mud that spread over the Hungarian countryside in October 2010 contained toxic pentavalent vanadium, according to analysis by Ian Burke at the University of Leeds, UK, published in Environmental Science and Technology (DOI: 10.1021/es3003475). 

The spill from an alumina tailings reservoir killed 10 people, covered 40km2, emitted radiation and released toxic trace metals. However, vanadium, which has not received so much attention in relation to the spill, is present in its bioavailable vanadium(V) form, which suggests that the more expensive and time consuming decision by the Hungarian government to remove the red mud, has prevented much of the metal remaining in the soil and subsequently entering the food chain. 

DNA nanorobots seek and destroy disease

Researchers in the US have created a DNA-based nanorobot that can work its way through cell cultures, delivering cargo to specific targets. The development could pave the way for programmable therapeutics, in which nanorobots would provide medical treatment only to certain types of cells or tissues. 

The field of nanomachines has taken off in recent years, mostly thanks to so-called DNA origami. In this technique, DNA strands can be folded controllably into a structure, onto which different molecules can be attached. Researchers have already shown that structures built using DNA origami can perform basic robotic tasks, such as sensing, computation and targeting cells. But, says biophysicist Shawn Douglas at Harvard Medical School in Boston, Massachusetts, US, no one has ever combined these tasks to do something more sophisticated, such as cell-targeted cargo delivery. 

Douglas, together with his colleagues, has now done this with a hexagonal, barrel-shaped DNA robot. The robot is just 35nm across and 45nm long, and is hinged at the base to clasp and unclasp in a clam-like manner. At the top, the barrel has ’locks’ made of short DNA molecules that unlock when they bind with antigen ’keys’, releasing the barrel’s cargo, such as antibodies. 

In the researchers’ experiment, described in Science (DOI: 10.1126/science.1214081), billions of nanorobots were released into mixed cell cultures, coming into contact with different types of cell. The nanorobots left cells without the appropriate surface key - the right antigen combination - alone. However, when a nanorobot came across a cell with the correct combination, its locks opened and the cargo was released - in some instances, killing the cell.