Developing international collaboration and microbiological techniques for producing of functional biominerals

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One of the great areas of current technological research and development is the search for nano-scale materials which, by definition, are less than less than 100 nanometres in size (and often as small as 1 nanometre, which is equal to 1 billionth of a metre). The driving force behind this effort is the use of nanoparticles in miniaturised magnetic and electronic devices, in biomedical applications, as catalysts, in energy production and in environmental clean-up. There are a number of bacteria that produce nanoparticles (bionanominerals) as part of their normal cellular activities, passing electrons from organic matter to metals to generate energy for growth. The result of these activities is the transformation of solids, such as common iron oxides, or liquids containing dissolved metals, into millions of nanoparticles adjacent to the bacteria. In our research programme we aim to exploit these natural manufacturers and to produce novel 'bionanomaterials' in what is an unexploited area of great potential. We aim to produce and understand the biomineralisation processes, to determine and control the important microbial activities, to promote conditions for biomineral production by environmentally friendly routes and to produce bionanomaterials better/different than/to their inorganic counterparts for a range of applications. In our work so far we have produced a number of these bionanominerals using a range of bacteria, and have shown that we can control the nature of the minerals produced by changing their growth conditions, changing the source materials and selecting the organisms with particular attributes. We have also shown that the properties of some of the particles produced are superior in terms of performance than particles produced in other ways. Our current research programme is aimed at producing bionanominerals in three areas.One group are based on magnetite (Fe304) minerals which are readily produced by a number of bacteria.. The chemistry and morphology of the nanoparticles will be changed by doping the starting materials (with elements such as Ni, Co, V). The second group are precious metal coatings or magnetic supports, such as Pt, Au, Ag and Pd, for use in catalysts. The third research focus is in the production of nanoparticles that can be used in electronic and optical devices. These are produced by bacteria that reduce elements like selenium to dissolved selenide which can be used to form particles five nanometre in size, such as CdSe. These semi-conductor materials are common constituents in many of the devices familiar to us such as TV screens. And finally we will be looking at the properties of these bionanominerals in environmental clean of toxic metals and organics; nanoparticles have excellent reactive properties which we have already shown neutralise mobile radioactive and chemical wastes. In all these investigations we will use state of the art technology including particle accelerators and molecular scale microscopes to determine the properties of the bionanominerals we produced, so that they can be compared in performance to nanoparticles formed by other methods, and so that we can 're-tune' our bacteria to produce the particles we want. Two major aims of the work are to develop the useful particles into actual working devices and to develop methods for bulk production, both essential if the UK Industry is to benefit from our work.