The Mesolens is a giant microscope objective designed for computer data acquisition rather than the human eye. It arose from a realization in the early days of confocal microscopy that confocal images could not be obtained of large specimens, because the available low-magnification objectives had too poor a resolution in depth. With the help of a professional lens designer, a lens has been created with an unprecedented numerical aperture of nearly 0.5 at a magnification of 4x and with a field size of 5mm. Applications are expected in the screening of human genes in transgenic mice, studies of large numbers of neurones in the brain and many other areas.
Features and Benefits of the Mesolens in Biomedicine
- The opportunity of 3D microscopy with larger specimens which are currently inaccessible. This allows us to see individual cells in situ, without losing the landmarks at the level of organs, blood vessels etc around them. This will help to answer questions such as ‘Are certain cells missing when embryonic development is abnormal?’, ‘Is the cytological structure in the periphery of a metastatic tumour present all around the tumour, or just at a few points that happen to be encountered in the tiny field of a normal microscope?’, ‘How do all the cells in an immune response interact in vivo?’.
- The capacity to see rare events. This includes very sparsely-distributed dividing cells in relatively quiescent tissues. It could show whether an abnormal mitotic index was present, indicating, perhaps, a proliferative tumour.
- The ability to see very faint fluorescence emissions. This will make it possible to reduce the optical radiation dose to the specimen during examination, permitting longer imaging duration with less risk of photo-bleaching and damage to surrounding cells or tissues.
- The opportunity to see bioluminescence in cells. Interest in bioluminescent probes is increasing, but current commercial imaging systems with sufficient sensitivity cannot resolve individual cells with the short exposure times of the Mesolens camera-based system. We already know from preliminary studies that the Mesolens can show the movement of bioluminescent tumour cells in time-lapse. This could provide an understanding of the biology of different types of tumour and rates of metastasis.
- The ability to record a massively increased amount of data, from a volume typically at least 100 times greater than a conventional microscope. This means that data can be collected and archived and analysed anywhere in the world at any time, post-acquisition. An obvious biomedical advantage is that automatic diagnosis algorithms can then be tested at leisure on the same specimen data. The data can also remain in the archive until optimised methods of searching it and presenting it (e.g. to a clinician) have been developed.