Single molecule fluorescence

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By studying molecules one at time, using fluorescence, specific complexes in a mixture can be identified and analysed without the need for any separation. With our collaborators we are exploiting single molecule fluorescence spectroscopy to study a range of biologically important molecules and processes. At present our main projects are:

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• Imaging the early molecular events that lead to the triggering of T-cells, a process that underpins the adaptive immune response and is remarkably  sensitive and selective.

• Imaging the early molecular events that lead to the triggering of Toll-like receptors, a key process in the innate immune response which plays an important role in causing inflammation in neurodegenerative diseases such as Alzheimer’s disease.

• Imaging and characterising the protein aggregates formed in the test-tube during aggregation reactions of disease-associated proteins and those present in human samples such as cerebral spinal fluid and brain tissue. We want to determine the aggregates responsible for causing neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease in humans and the mechanisms by which they damage cells and spread through the brain.

• Determining the structure and organisation of DNA in the nucleus of cells and  how this is regulated and changes during  cell differentiation.

• Imaging aggregates of P53 and determining the role of these aggregates in the development and spreading of cancer.  

• Developing and improving our imaging methods. At present our focus is developing methods to image protein aggregates at 20 nm spatial resolution and determine their composition and structure.

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Scanning nanopipette

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In collaboration with Professor Korchev at Imperial College we have developed a method based on a scanning nanopipette that allows robust, high resolution, non- contact imaging of living cells, down to the level of individual protein complexes. It can also be used to probe function by performing nanoscale assays such as locally deliver controlled amounts of reagents or performing single ion channel recording. The figure shows the University of Cambridge crest written in fluorescent DNA. We are using this method to watch the details of biological process taking place on the surface of living cells and to directly observe protein aggregates damage neuronal cells.