Restraining and studying molecules, two at a time – Photonics | The usual way of studying how molecules react to a catalyst is to put them into a solution and observe – typically huge numbers of reactions. This works to a point, the point being the amount of detail that can be surmised from so many individual reactions. Now instead of observing a whole mess of molecules, what if you could observe precisely two molecules react? This level of resolution might lead to new insights, but how do you get to observe just two molecules? That’s what the technique devised by a team of UCLA (University of California Los Angeles, USA) researchers does – it ‘restrains’ exactly two molecules of photosensitive material (materials used in solar cells in this case) using a shape-fitting form of nanoparticles. The nanoparticles assemble on a surface (substrate) of gold so that there are shapes (defects) that precisely fit the shape of the target molecules. These molecules are ‘stuck’ to the shapes so they can be observed with a scanning tunneling microscope while they are activated with ultraviolet light. The technique is called regioselectivity, regio being the catalyst (or reagent) and the selectivity is the way in which the molecules align. In this case, the researchers are attempting to find better alignment for critical molecular components in solar cells with the hope of increasing the efficiency.
[Science Magazine 11 March 2011, Creating Favorable Geometries for Directing Organic Photoreactions in Alkanethiolate Monolayers]
Nanoballoons for cancer therapy – Nanomedicine | There are many ways researchers are looking into using nanostructures (such as nanotubes, nanowires, nanoparticles) to deliver medicine to very specific targets (often cancerous tissue). One of the more promising was developed by a research team at Princess Margaret Hospital (Ontario, Canada) that uses what might be called nanoballoons, structures no bigger than 1/100,000 the width of a human hair that look like a colorful balloon. The nanoballoon is created by combining chlorophyll and a lipid (fat) and distinguishes itself from other nanoparticle forms in being biochemically safe (non-toxic) and usable in several different techniques: Photothermal therapy to heat cancer cells until they are killed, photoacoustic therapy to find and remove cells, and as a container to hold chemotherapy drugs for precise delivery to a cancerous area. The research has prototyped the nanoballoon techniques but much more work needs to be done to show that this particular approach can be used clinically.
[Nature Materials 20 March 2011, Porphysome nanovesicles generated by porphyrin bilayers for use as multimodal biophotonic contrast agents]
White dwarf stars: A good place to look for Earth-like planets – Exogenous Life | Stars come in many sizes and conditions, although ‘enormous’ and ‘very hot’ sort of cover the lot. However, there are also a number of ‘colored’ star types known collectively as ‘dwarfs’ – red (low mass), yellow (like our Sun), white (a dying star), black (a white dwarf emitting no visible light) and brown (smaller than a star with minimal heat). In general these stars are less energetic (including less explosive and violent), a condition that favors retaining planets in the ‘Goldilocks zone’ – orbits that are close enough to the star to get sufficient heat, but not in danger of being destroyed by emissions from the star. This is the zone Earth occupies and it is presumed that similar earth-like planets might exist. The implication is that such planets could harbor life. A new paper by Eric Agol at the University of Washington (Seattle, USA) suggests that white dwarfs would be a good place to look for these planets. Because white dwarfs are small and relatively cool, planets can exist much closer to the star and that should make them easier to spot with current telescope technology. There are approximately 20,000 white dwarfs relatively close to Earth.
[Astrophysics Journal Letters 5 April 2011, Eurekalert]
A primordial soup revisited – Origin of Life | In 1953 Stanley Miller began a series of experiments designed to explore the idea of a primordial soup, the mixture of chemical ingredients that could lead to the origin of life on Earth. His first research used a simple mixture of water, methane, ammonia and hydrogen – common chemicals in asteroid and meteor bodies – through which was passed an electric current. The results, which were startling at the time, were a number of complex amino acids, the building blocks of life. Miller continued his research through 1958 but he died in 2007 leaving his notes and experiments unfinished. One of Miller’s former students, Jeffrey Bada has picked up the research, using tools and instruments more sophisticated than those available to Miller. In one new experiment, based on Miller’s notes, hydrogen sulphide (the smell of rotten eggs) was added to the mix. The results included an astonishing 23 amino acids, four amines and seven organo-sulphur compounds. Keep in mind these are pre-biotic materials that are considered necessary for organic life but have not yet been combined in a way to actually create life. What that process was, as yet, is unknown. Nevertheless, the results indicate that from some very common chemical substances and a simple electrical discharge the basic organic components of life can be made. This knowledge increases the probability that life could have formed many places in the universe.