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Performance Active Nanoscale Devices Obtained by Rational Assembly

Final Report Summary - PANDORA (Performance Active Nanoscale Devices Obtained by Rational Assembly)

The PADORA project aimed to add a new dimension to nanotechnology in order to make nanoscale designs more biology-like in one important way. This is to create the ability of a nanoscale system to maintain itself far from chemical equilibrium by the constant conversion of energy, which can be supplied in the form of a fuel (food), or by other sources such as electricity. We can hence envisage this design as a dynamic process rather than a static object. This is fundamental to all life and, together with the typically sophisticated molecular scale architecture, responsible for the superior properties and abilities of biological systems. All existing technologies lack this property. The project has made significant advances in creating the functional units or building blocks of such designs, and in integrating them in non-equilibrium environments where they have demonstrated activity. Concretely, we developed for the first time nanoparticles that can shuttle electrical charge across physical boundaries such as biological membranes or the interface between immiscible liquids in an emulsion. Different types of such particles have been made successfully, and we can now select to some extent, which charge carriers (ions) they are able to transport. These processes conceptually closely resemble biological energy conversion, as it takes place in every cell of every organism all the time, although completely different, non-biological units are being used. The project was successful in establishing this machinery but unsuccessful in achieving the actual conversion chemical or electrical energy into another useful form, as it is typical in living cells. This can be compared to having developed a bicycle that, for now, is only running downhill. As always in research towards ambitious and complex goals, we have also made other important advances that were peripheral to the core theme of the project. These are (i) the ability to monitor minute changes in the molecular scale shell surrounding a nanoparticle, (ii) the first electron microscopic observation of the nanoscopic swelling of a thin film of nanoparticles of the type used in innovative sensor technology, (iii) a new nanomaterial that disperses at low temperatures and agglomerates at high temperatures, (iv) new designs of gold nanorods and procedures for the labelling and tracking of biological cells, (v) identification of singlet oxygen as a key intermediate responsible for the killing of cells by gold nanoparticles under laser light illumination, and (vi) the first observation of electrocatalytic metal deposition onto nanoparticles.