There are two main types of studies in biological sciences, those does in vivo and those done in vitro. In vivo translates as ‘in life’ and refers to studies that have been done in living organisms. In vitro on the other hand translates as ‘in glass’ and refers to experiments on individual cells or tissues done in petri dishes. These two studies are rapidly being joined by a third form of studies called ‘in silico’, referring to simulations performed on computers or literature data-mining studies.
Intravital imaging is a technique that blends the best bits of in vivo and in vitro imaging to watch what cells do in three dimensions in their natural habitat. It allows researchers to view living tissue within organisms as a single layer of cells rather than an overlapping mass, allowing greater clarity of images.
To do this, components of cells such as histones or transmembrane proteins are tagged with fluorophores that glow when activated by lasers. Two lasers are aimed at the tissue along orthogonal axes. Where the lasers intersect the fluorophores are activated, allowing a single layer of cells to be isolated. The light released makes imaging a single plane in 3D tissue possible.
Metastasis of cancer cells is a key developments in cancer progression. It occurs when cells break away from the original tumour and escape into other organs to form new secondary tumours. This is noticeable because the tumour cells retain the same characteristics of the cells they originally mutated from. So you might end up with cervical tissue in your intestines. In this image, the secondary tumour has invaded lung tissue.
Artwork for the Gurdon Institute’s upcoming talk by Erik Sahai on Intravital imaging of cancer cells.