The scientists obtained a 3D model of live zebrafish larvae with resolution down to single cells. article about it published In Optica magazine.
Danio rerio is a popular aquarium fish often used in biological experiments. Ji Yi of Johns Hopkins University and colleagues used its larvae to test the dynamic fluorescent microscopy system; at this time, the researcher observed the glow of an object from a laser aimed at it (special fluorescent proteins were injected into living objects). This method allows you to observe individual cells of living organisms, but usually has a limited field of view like other microscopy methods and does not allow you to see all millimeter organisms.
The authors were able to circumvent this limitation by using a special optical element – a transmissive diffraction grating. As a result, the scientists managed to obtain a three-dimensional image with a resolution of 2.5 × 3 × 6 microns, up to 5.4 × 3.3 millimeters in size. Thanks to this, they made volumetric recordings of the neuronal activity of the entire body of zebrafish larvae at a frequency of 2 Hz, which makes it possible to study the functioning of the nervous circuits of vertebrates. The authors also demonstrated volumetric recordings of whole body blood flow at a frequency of 5 Hz, allowing to monitor the movement of cells throughout the entire circulatory system.