Mesolab: A Centre for Optical Mesoscopy for Biomedical Research at the University of Strathclyde

During the last twenty years, several different microscopes have been invented which can sharpen the eyes of biomedical scientists, showing more detail in an ever-tinier field of view. Our microscope, developed only recently in the UK, represents lateral thinking: we have broadened the field of view enormously, while keeping the acuity of a conventional microscope. This innovation allows a hundred-fold increase in the volume of the specimen from which sub-cellular detail can be obtained. Individual cells are seen in detail, but so also, for the first time, is their three-dimensional relationship to the whole organ or body.

The first confocal results of our optical 'mesoscope' were obtained in the last six months and announced in the 2012 Royal Society Leeuwenhoek Lecture and in a profile in the journal Science. There is now strong worldwide interest because the benefit is obvious in the images already published. There are many applications: here we will describe one of the most important as an example. One image (shown in the Case for Support) shows a median optical section of an entire mouse embryo five millimetres long. This is the first ever confocal image of such a large and thick specimen, with sub-cellular detail including individual Golgi bodies in the same image. The participants in this proposal include the two top UK labs in the field of mouse genetics, where researchers are eagerly seeking to use such images for phenotypic screening of human genes in mouse embryos, one of the most important and large-scale activities in modern biomedicine. We propose to also include in our project equally important but quite different areas of biomedical research where it is almost certain that the optical mesoscope will change the way that work is done.

This proposal to the MRC is to set up a centre, the Mesolab, and purchase two optical mesoscope systems at cost from the fledgling manufacturing company Mesolens Ltd (with which we have already worked successfully using our expertise in optical physics and software development to build the prototype confocal system). We are currently pursuing this work with modest but vital EPSRC Knowledge Transfer Agreement funding and support from the University of Strathclyde, as well as a single prototype Mesolens originally developed in the MRC Laboratory of Molecular Biology, Cambridge.

We will use the proposed MRC Mesolab facility to develop multi-photon scanning, high-resolution and fast camera imaging, and other imaging modes for the optical mesoscopes, with strong support in manpower, expertise and infrastructure from the University of Strathclyde and substantial input of material support and expertise and intensive design participation by the company, who will be our Project Partner. This development work will be completed within the first three years of the project, but even during this phase biomedical work will occur and there will be synergy between the collaborating biomedical users of the systems and the designers. This engagement (which the large microscope manufacturers have hitherto failed to achieve) will be a key feature of our project. In the second phase, the work will consist exclusively of optimisation of experimental procedures in each application to yield the greatest biomedical benefit.

We expect optical mesoscopy to be similar to the original development of the beam-scanning confocal microscope by the MRC, in providing a transforming technology for biomedical research. The creation of the Mesolab will allow scientists rapid access to this next generation microscopy method, which they are already seeking.

It is a great advantage in biomedical research if the field of view can be extended to cover the entire object, e.g. an embryo or an organ, without sacrificing sub-cellular detail in the image. In a conventional microscope any attempt to view large fields reduces the spatial resolution. Not only is detail lost in the image, but depth discrimination (required for confocal function) is strongly compromised. What is needed is a microscope lens with a low magnification (e.g. 4x) and yet a high numerical aperture (approaching 0.5). The Mesolens was designed by our Project Partner Mesolens Ltd to meet this need.

We propose a Mesolab facility at the University of Strathclyde equipped with two Mesolens systems. The first will use a high-end camera capable of high-spatial resolution recording at >96 MP and a smaller-chip, fast, high sensitivity sCMOS camera, for wide-field imaging and digital lightsheet scanning mesoscopy. The second system will also have modest epi-fluorescence capability but will be used primarily for laser scanning confocal (already demonstrated), multi-photon and fluorescence lifetime mesoscopy.

We will use the optical mesoscopes to answer a host of key technical biomedical questions, including the following: can every cell in a mouse embryo be imaged using optical mesoscopy and what are the best preparative methods? Will this pinpoint the cellular basis of genetic defects? How deeply can these optics penetrate into living tissue? How much can the duration of fluorescence studies be increased because of the optical mesoscope's improved light collection? Can cell migration inside tumours be followed by using bioluminescent markers, as we suspect?

To our knowledge, no similar technology is being developed anywhere in the world. We have a head-start in our unique achievement of adapting a Mesolens for laser scanning imaging and we have the right expertise in optical physics and software design to drive this project forward.

- Who will benefit from this research & how might they benefit?

We deal with each group of beneficiaries in turn:

Academic Beneficiaries are primarily biomedical researchers and optical physicists and engineers, and later clinicians and diagnostic pathologists.

Almost all areas of biomedical research where microscopy is already used will benefit, and the benefit will be felt immediately since the same specimens and reagents may be used but better studied by bringing them to the proposed facility. One specific example is the study of mouse embryos, for which the Mesolens was initially specified. The two foremost UK labs in this field are already eager to use this technology for phenotypic screening of human genes in transgenic mice, to improve the online atlas of mouse development which is used worldwide, and to develop new mathematical methods for analysis of developmental data. The impact of this on the identification of genes implicated in human disease will be enormous.

In photographic terms, the Mesolens is a 'fast lens' and so the impact on dynamic neurophysiology could be great. The relatively high angle of capture indicates that this project will impact all forms of microscopy in which faint fluorescence and bioluminescence signals have to be captured over a wide area.

The 'comet' DNA damage assay which is already using the optical mesoscope to great effect (project participant, Dr Marie Boyd) is an example of how many types of high-throughput screening will benefit. There are a host research areas where the ability to record in greater detail all structures, including individual cells and cell-contacts within a large volume is likely to increase efficiency a hundred-fold.

Public sector beneficiaries will include healthcare professionals and police forensic scientists. We are already in discussions with NHS pathologists who wish to install an optical mesoscope in a new pathology centre in Glasgow and with opthalmologists in Addenbrooke's Hospital, Cambridge. The proposed Mesolab will allow diagnosticians to see the technology and decide whether the increased accuracy and speed of examination justifies the cost of the optical mesoscope.

Private sector beneficiaries are anticipated, once the phase of academic development is complete. Dr Amos of our project partner Mesolens Ltd worked in the private sector in the development of confocal microscopy and, largely as a result of his efforts, instruments were installed in the research laboratories of companies in materials science and in the food industry. The work may also raise the profile of the UK's strength in high-end optics and electronics and so facilitate exports of products that have hitherto been made almost exclusively in Germany or the Far East.

The general public will benefit ultimately through discoveries in fundamental biomedical science and possibly through use of optical mesoscopy for diagnosis.