Final Report Summary - SANTS (Synthesis and nanotechnologial application of tethered silicates)
The SANTS project is based on the observation that diatoms, which are small unicellular algae, possess internal silica skeletons that are laid down due to the silica precipitating activity of specialised proteins called silaffins. These proteins have a highly repeating structure in which the repeated sequences are decorated with additional amine and phosphate groups. Whilst silaffins themselves are potent silica precipitants, synthetic peptides corresponding to these repeats will also act as silicating agents and will allow silica nanoparticles to be generated, provided phosphate is also supplied. Moreover, several polyamines, which can be viewed as peptide mimetics also act as silica precipitants. The biotechnological facility of these observations is that the biosilicates can entrap and immobilise a wide range of enzymes with dramatically higher efficiency than conventional immobilisation procedures, and that biosilica entrapment also serves to stabilise and protect the entrapped enzymes.
Production and characterisation of nanosilicate particles catalysed by R5, PEI and poly-L-lysine has successfully been achieved. As a result, a number of common protocols were available to the project partners in the production of nanoparticles. The project progressed well from the generation of silica particles to the point where a number of enzymes (glucose oxidase, acetylcholinesterase, lipases, mannitol dehydrogenase and choline oxidase) could be entrapped or immobilised using silica matrices, or on electrode surfaces. Many potential sources of R5 peptide were scrutinised and a reliable supplier chosen so that high quality peptides could be supplied to all appropriate partners. R5 peptide with an N-terminal thiol was also sourced and supplied as well as R5 multimers and modified R5 peptides, bearing phosphate groups, extra basic group etc. Structure function studies were performed with the native and modified R5 peptides with respect to both nanoparticle formation and surface silication.
Adaptation of the natural silication process through the use of synthetic peptides and peptide mimics to catalyse nanosilica production has been fully explored by the SANTS project partners. The materials produced have shown to be of use in the production of biocatalytic matrices, ultramicro-biosensors and nanoparticulate optical biosensors. Manufacturing protocols have been developed that allow the reproducible deposition of nanostructured surfaces for sensing and synthetic applications and also, the potential exists for the production of self-assembling and self-organising structures. This will lead to the development of a range of materials that will be of significant use in a range of industrially important areas.
Production and characterisation of nanosilicate particles catalysed by R5, PEI and poly-L-lysine has successfully been achieved. As a result, a number of common protocols were available to the project partners in the production of nanoparticles. The project progressed well from the generation of silica particles to the point where a number of enzymes (glucose oxidase, acetylcholinesterase, lipases, mannitol dehydrogenase and choline oxidase) could be entrapped or immobilised using silica matrices, or on electrode surfaces. Many potential sources of R5 peptide were scrutinised and a reliable supplier chosen so that high quality peptides could be supplied to all appropriate partners. R5 peptide with an N-terminal thiol was also sourced and supplied as well as R5 multimers and modified R5 peptides, bearing phosphate groups, extra basic group etc. Structure function studies were performed with the native and modified R5 peptides with respect to both nanoparticle formation and surface silication.
Adaptation of the natural silication process through the use of synthetic peptides and peptide mimics to catalyse nanosilica production has been fully explored by the SANTS project partners. The materials produced have shown to be of use in the production of biocatalytic matrices, ultramicro-biosensors and nanoparticulate optical biosensors. Manufacturing protocols have been developed that allow the reproducible deposition of nanostructured surfaces for sensing and synthetic applications and also, the potential exists for the production of self-assembling and self-organising structures. This will lead to the development of a range of materials that will be of significant use in a range of industrially important areas.
