molecularlifesciences:

5 Reasons Why CLARITY Will Change the Life Sciences

We’ve all seen the gorgeous 3D constructions of the brain created by Karl Deisseroth’s group using a technique called CLARITY. This technique is more than just the eye candy we love so much on Tumblr. I recently attended a lecture by Deisseroth, and his work is nothing short of Nobel prize worthy. 

Here are 5 reasons why CLARITY will change the molecular life sciences.

1. CLARITY clears fatty molecules.  Fats and other hydrophilic molecules absorb and diffract light, and by washing away the molecular structures that screen light, micrographs can be clear and crisp.  These images show a visible difference. 
2. CLARITY links proteins in a mesh-like gel.  Most of us know about formaldehyde and its ability to preserve biological matter.  Using a similar chemical reaction, proteins are kept in tact in their relative position by being linked to each other.  This means that even with the fatty parts washed away, the proteins will maintain their spatial organization. 
3. CLARITY holds on to proteins.  As a consequence of the chemical linking, the proteins of interest stay in place even when the sample is washed.  The amount lost is incredibly low compared to other methods of clearing, which means that the researcher will have a more realistic amount of protein in the sample.  More proteins means more gorgeous micrographs.
4. CLARITY means no more sectioning.  One of the greatest challenges for neuroscientists has been capturing whole neurons in vivo.  A single neuron can run the length of your leg.  CLARITY creates “never-sectioned” samples, removing the guess work of reconstructing slices. Personally, sectioning is my least favorite activity.
5. CLARITY allows for multiple labels. Drumroll please.  Finally, Deisseroth’s group has shown that samples can be labeled multiple times with high reliability.  The meshwork is tight enough that immuno-staining (i.e. labeling with antibodies) can be done multiple times with washing.  Most techniques are limited to 2-3 molecular probes at a time.  This provides an opportunity to visualize many protein targets. By stacking 3D images of each protein marker, the researchers create the colorful visuals seen above.

As you can guess, CLARITY resolves many of the largest challenges of molecular biology and related sciences, but there is one more bit of great news. The Stanford-based group released their protocol for everyone to use!

Viva la scientific revolution!

Read the original paper here, watch the video here, or view the Nature News article here. 

More like this at molecularlifesciences.tumblr.com

References:
Chung, K., Wallace, J., Kim, S. Y., Kalyanasundaram, S., Andalman, A. S., Davidson, T. J., … & Deisseroth, K. (2013). Structural and molecular interrogation of intact biological systems. Nature 496.151

Note:
CLARITY is the method used to prepare samples, it makes tissue see-through.  It is the confocal microscopy that focuses a laser on the sample an excites the fluorescent tags added by the researcher.