Writing with Lightning (Resubmission)

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We have become accustomed to rapid advancements in computing power, and these have resulted from relentless advances in manufacturing technology that have enabled year-on-year reductions in the sizes of electronic components in integrated circuits to continue unabated for forty years. However, such advances in miniaturisation are potentially not restricted simply to computers, but may reach into many areas of life, including medicine. For example, the determination of the human genome, the complete set of genetic words from which the description of a human being is written, has recently been completed. While this is a great achievement, we do not understand the language that these words speak / how do they instruct cells to behave the way they do, to produce proteins with particular structures and functions? How are they related to disease and ageing? New technologies based on miniaturised devices have a critical role to plan in advancing our understanding. Such devices can provide rapid methods for the interrogation of huge sets of data. One of our goals is to develop a zepto-array , a system based on an array of nanoscale spots of biological molecules that could be used to analyse biological specimens with a sensitivity of better than 600 molecules, a million times better than any existing technology.The extension of miniaturisation into such areas, loosely described as molecular nanoscience, raises new and demanding challenges. The patterning techniques that have been developed so effectively for electronic device manufacture are harder to apply to molecular materials. A major challenge in all such miniaturisation techniques is the lack of techniques that enable the control of molecular structure from the level of a single molecule up to about the current limit of commercial device fabrication methods, 100 nm. In this critical length scale there is no technique capable of routinely manipulating molecular structure with a resolution comparable to that of a single macromolecule. The objective of this project is to develop just such a technique.We will achieve this ambitious objective by exploiting, in combination, several recent advances and integrating them with new and sophisticated chemistries. When light is forced to go through very small holes, it diffracts, no longer forming a well-defined illumination. However, by working in the near-field , with the hole very close to a solid surface, this problem can be avoided. Recently we showed that we could write very small structures by using near-field light sources and a suitable photosensitive material. These structures were nearly as small as a single protein molecule. It has recently been found that very small spots may be illuminated by using a metal tip held very close to a surface and shining light on it. The illuminated area may be even smaller than when an aperture is used. However, this has not been explored as a tool for patterning molecules. We will test this here. Light is made up of photons, tiny particles. Some optical processes require the absorption of two photons at once, and these have a very sharp dependence on the light intensity. By combining these processes with the use of a metal tip to cause the illumination of the sample, we believe that we can confine the patterning process even further still. If we are successful, we will have developed a new method for doing chemistry with both exquisite chemical selectivity and unparalleled spatial resolution.