Nanoparticles - particles with a size of nanometres, around one billionth of a metre - have special properties which encourage their use in a wide variety of products such as clothing, sunscreens, toothpaste and food products. A significant quantity of man made nanoparticles enter the environment every year although concerns exist in relation to their probable toxicity. The latter encourages regulation but this is hindered by the lack of available analytical techniques for the rapid, cheap and reliable detection and characterization of the particles especially in the solution phase. This project addressed these issues by developing a methodology and instrumentation capable of detecting and identifying nanoparticles whilst measuring their concentration In particular analysis under flowing and batch conditions is now possible and a metrology has been established by which nanoparticles in solution can be sized without assumptions as to their shape and with a much improved in situ sensitivity which allows particles as small as 5nm to be analysed - a value which is a substantial improvement over prior methods such as Nanoparticle Tracking Analysis or Dynamic Light Scattering. Concentrations as low as femto-molar can be interrogated in a matter of minutes. The methodology has been validated with and applied to silver nanoparticles in authentic real world media such as tap water, bottled water and in human saliva.
The technique has been extended beyond simple metal or metal oxide particles to allow electrochemical detection of nano-entities most generally. In particular viruses, enzymes and especially bacteria have been studied at the single particle level (and above). In particular the detection of E.Coli at the single entity level has been demonstrated and used to develop sensitive sensors for the easy, rapid and reliable detection and quantification of the bacteria. The approach is being developed in conjunction with a European based SME with the aim of providing cheap and disposable sensors for the food industry to allow the rapid assessment of bacterial contamination. A timescale of ca 12 - 18 months to market has been agreed and a licence deal is imminent. Significant impact on the quality of life within Europe is expected if the product is successfully translated to market.
Beyond the food industry the next obvious area for potential application of electrochemical bacteria sensing is in the medical and healthcare area since the approach can be generalised beyond E.Coli. Further funding has been sought in parallel with the expectation of the establishment of a possible spin out company. Possible investors are being approached through Oxford University Innovation (OUI).
In summary the project has first realized instrumentation for a step change in the metrology of manmade nanoparticles and second led to the development of electrochemical sensors for bacteria with prospects for major impact across the food and healthcare industries.
