At the 247th National Meeting and Exposition of the American Chemical society (ACS), researcher Anne Morrisey from Dublin City University reported her team’s new technology, which hopes to provide a simple water purifying system that makes use of sunlight. Morrisey’s team began by using a compound called titanium dioxide (TiO2). TiO2 can act as a catalyst; something that speeds up a reaction without being used up itself, but is usually dependent on UV light. In order for this compound to be useful, it would need to be active in visible light. Therefore, the group started investigating the best shape of TiO2 which would allow this property. Although they found the ideal conformation, it was later discovered that TiO2 was inadequate when used alone. This is where graphene came in. Graphene sheets are made of carbon, and are only one atom thick. The cocktail of these two ingredients together proved effective in the system. The graphene was sticky, catching the pollutants as they flowed through, thus enhancing their proximity to the TiO2 catalyst. But it isn’t quite yet ready to go on the market; the team first need to make sure that the system does not produce harmful by-products when substances are broken down. Tests on the anti-inflammatory drug diclofenac proved successful. This common veterinary drug notoriously caused the death of large numbers of vultures in India and Pakistan.
This system was not designed as a first-line water purification system; rather it would serve to remove stubborn harmful molecules from water after it has already been treated by conventional methods. It’s hoped that it could help to remove pollution, pesticides and pharmaceuticals to make water safe to drink. Modifying current purification systems to get rid of these residual compounds is not a viable alternative due to the high costs involved. Ideally, the system would be developed to fit into water pipes in areas where large-scale water treatments are not yet feasible. The fact that it is powered by sunlight makes it an ideal and simple candidate solution to a severe problem.
A group of scientists from Massachusetts Institute of Technology (MIT) have developed a system aimed at increasing the energy yield of plants through the use of nanomaterials. Using a similar system, they also hope to be able to assign plants the novel function of chemical detection, which could be used to sense explosives amongst other things. This new field of research has been entitled plant nanobionics, and it is hoped these findings will precipitate a wave of research into this exciting new area. Next, the team wanted to increase the amount of sunlight that the chloroplasts can use to make energy. They did this by using the same technique just described, but instead inserted semiconducting carbon nanotubes, which actually increased photosynthetic activity by almost 50%. This was achieved by the nanotubes broadening the wavelength of light that the chloroplasts can capture. To take this research further, the group started using the whole organism as oppose to just the chloroplasts. Infusion of nanoparticles into the model plant Arabidopsis thaliana through little pores present on the underside of the leaf amazingly managed to enhance the flow of electrons during photosynthesis by 30%. However, it has not yet been elucidated whether this actually increases sugar production.
In a paper released in Nature Materials yesterday, a team led by Michael Strano were able to improve a plants’ ability to capture light energy by 30%. Alongside this, they were able to increase the photosynthetic ability of chloroplasts by almost 50% In a press-release, Strano said “Plants are a very attractive technology platform. They repair themselves, they’re environmentally stable outside, they survive in harsh environments, and they provide their own power source and water distribution.” Strano’s lab turned to chloroplasts during a project where they hoped to be able to isolate these organelles and use them in solar cells. Prior to this study, chloroplasts could not be used when isolated from the plant because harmful molecules called oxygen radicals eventually start to damage the components of the chloroplast. Normally, the plant would prevent these radicals from causing such damage. In an attempt to avoid this situation, the group implanted a type of nanoparticle called nanoceria into the chloroplasts; these mopped up the reactive molecules that were responsible for the damage. They did this using a technique called lipid exchange envelope penetration, which involves coating the nanoceria with a highly charged molecule, allowing the passage through the fatty chloroplast membrane. Using these carbon nanotubes, the researchers hope to progress their work by converting plants into chemical sensors that can detect and monitor pollution levels and bacterial/fungal infection. Hopefully, this is just the beginning to a very fruitful field.