Chemistry without frontiers

Research into possible future uses of chemicals is venturing into nanotechnology and stem-cell research. Herb Ladley reports.

• Electrospinning

Electrospinning is "an antique technology that has been forgotten and rediscovered", says Andreas Greiner, a professor at Germany’s University of Marburg who is researching new applications for nanofibres created by electrospinning. First patented in 1934, electrospinning allows the creation of long polymer fibres at widths of only a few billionths of a metre. The technology underwent a revival in the 1990s, as more and more uses for nanospun fibres have been found.

The incredibly small nanofibres are useful in producing tissues for use in technical situations and air filtration. Filters made from electrospun fibres have a higher surface area than traditional air filters, increasing their efficiency. The technology is also useful in producing textiles. One of the most interesting applications of the technology currently in development is the idea of embedding medicine in nanofibres made from soluble polymers. The nanofibres would then be inhaled by the patient and absorbed in the lung, along with the medicine. Greiner says that the technology is still only in the initial research phase, but the method should be more user-friendly than injection and more efficient than other methods of delivery, such as a traditional aerosol inhalant.

Electrospinning also offers environmental benefits. With traditional techniques of spinning a polymer into a fibre, the polymer has to be dissolved in a solvent, many of which are bad for the environment. But electrospinning allows the use of water as a solvent, even to produce fibres that are not water-soluble. Another environmental application, says Greiner, is embedding bacteria in tissues made of nanofibres to act as an enzyme factory for the destruction of unwanted chemicals.

• Nanotechnology and biofuels

Developments in nanotechnology could help in the effort to convert biomass into fuel. Researchers have figured out how to attach gold particles smaller than one-billionth of a metre to protein molecules, creating new structures that could be used as catalysts for converting biomass or as "‘vehicles’ for targeted drug delivery", according to a statement from the Brookhaven National Laboratory in the US, where the research is conducted.

One of the most useful applications of attaching gold nanoparticles to proteins is determining the structure of proteins, according to Ray Brinas, a researcher who worked on the project. "Labelling with gold nanoparticles you can specifically target sites on the protein," explains Brinas. The nanoparticles, once attached to the proteins, can be used as a reference point for analysis of proteins.

In order to engineer a gold-protein structure, the researchers attached Nickel NTI to the gold nanoparticles, and the Nickel NTI in turn attached to tags that had been genetically engineered on the protein molecules, says Brinas. The result was a grid of proteins about one micron - or one-millionth of a metre - across.

The new method can also be used to attach enzymes together in an array. Such an array would be "more highly concentrated and more efficient" for catalysing biomass in the production of biofuels, though the research has yet to be applied in this way. The arrays would also be bio-compatible, meaning they are not likely to induce an immune response, according to Brinas, making drug delivery another potential application.

• Neuron growth

Unlike most other cells in the body, neurons do not regenerate when they are damaged or destroyed. But a new chemical, neurodazine, could prove to be the illusive trigger in promoting neuron growth, according to research at Yonsei University in South Korea. Embryonic stem cells - human cells that can develop into any cell in the body - are thought to hold such promise, but the researchers call the potential chemical solution "a more convenient and attractive approach", given the ethical issues surrounding the use of human embryonic stem-cells.

The chemical could lead to treatments for degenerative diseases such as Parkinson’s and Alzheimer’s disease, which attack the nervous system.

Neurodazine was found by comparing an imidazole library with mouse myoblasts - a type of stem-cell found in muscle fibre, where it was found to trigger the growth of neurons.

The researchers describe their discovery as the first chemical of its type shown to induce neurogenesis in "cells derived from mature, human skeletal muscle", in a report published in the journal of the American Chemical Society. They note that although retinoic acid is known to induce neural differentiation, it comes with a number of side-effects that make it less useful for potential medical applications.

Research into possible future uses of chemicals is venturing into nanotechnology and stem-cell research. Herb Ladley reports.