​Two newly developed methods will help researchers to study the 3D structure of complex surfaces and individual neurons better than ever before. Sebastian Munck and Natalia Gunko report new imaging protocols that will advance neuroscience and (bio)imaging in general.

From lefo to flies: "Almost" allows unprecedented 3D surface imaging 

Recent developments in 3D microscopy have revolutionized biomedical research by enabling the imaging of whole model organisms as well as cleared mouse embryos and organs. In many cases, however, this requires making a sample transparent using chemical ‘clearing’ methods that are time intensive and can’t be applied to every type of sample. That is why Sebastian Munck and his team developed “ALMOST”: A Label-free Multicolor.

Optical Surface Tomography method. It provides a 3D surface reconstruction of non-transparent samples, including information on their color and reflective properties. Munck believes that many research fields will benefit from this straightforward way of documenting and quantifying 3D surfaces, as ALMOST can be applied to both biological and non-biological samples: “The ability to record the surface of a medium-sized object in 3D opens perspectives for digital repositories of zoological and botanical collections and enables a link to 3D printing of these objects. From pigment analysis to virtual reality, or even art, the possibilities are endless.”

Publication: Kerstens et al., BMC Biology 2019

From silver to gold: optimizing a century-old method to study neurons in more detail

In the late 19th century, Camillo Golgi developed a method to stain the long protrusions of individual brain cells in what he called ‘the black reaction’. Now referred to as the Golgi method, the protocol has been refined over the years and proved instrumental for many groundbreaking advances in neurobiology. Nevertheless, it also has an important drawback. After performing the protocol, no additional electron microscopy studies can be done on the stained neurons. This is because the black reaction results in the formation of large, electron-dense silver deposits that mask ultrastructural details from further enquiry.

To solve this problem, Gunko and her team adapted the Golgi method for electron microscopy by replacing silver salts with gold salts, resulting in far smaller particles that are often deposited at the periphery of neurons. “It’s the first successful use of a Golgi-based staining technique for tracing neurons over their entire length, preserving the ultrastructural details,” says Gunko, who immediately applied the technique to study neuronal ultrastructure in an Alzheimer’s disease model.

Publication: Vints et al., Scientific Reports 2019

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