Clearing Up the Gray Matter: Olympus SCALEVIEW-A2 and 25x Objective Make Tissue Transparent Allowing 4 mm-deep Microscope Imaging
Scientists often study life processes by peering into biological organisms to see their structure and function. But brains and other tissues are almost all opaque, making it difficult to see deep inside. Now, thanks to a liquid that can literally make tissue transparent and minimizes light scatter, along with a new super-long-working-distance Olympus microscope objective, scientists are producing vivid 3D images of structures deep inside mouse brains and other animal organs.
The reagent was developed by a research team at RIKEN Brain Science Institute in Japan; Olympus is now offering it, together with its specially designed 25x, NA1.0, 4 mm-working-distance companion objective, to researchers in North and South America.
The SCALEVIEW-A2 reagent and SCALEVIEW 25x objective are designed to boost the capability of multiphoton microscopy and allow scientists to look deeper into tissue than they ever could before. In the mouse brain, for instance, the RIKEN team as imaged neurons and blood vessels down beyond the white matter, 4mm beneath the surface. Until now, even advanced optical methods did not allow researchers to see this deep beneath the surface due to light scatter within the tissue. Furthermore, most optical techniques required slicing dead biological tissue into very thin sections, which damaged specimens and made it challenging to visualize exactly how slices fit together and, critically, how neural filaments connect throughout the brain.
“I’m very excited about the potential,” said Dr Atsushi Miyawaki, part of the RIKEN research team in a recent interview with The New York Times. Dr Miyawaki’s team is working on imaging the mouse brain as part of the worldwide Connectome project – a global effort to understand the structure, interconnectivity and function of animal (and ultimately human) brains. The reagent and objective may help neuroscientists map the architecture of the mouse brain, and ultimately, other organs as well.
There are two keys to the research protocol. First, the reagent clarifies fixed biological tissue and makes it gelatinous and clear. Next, the specially designed microscope objective, which has been optimized to work with the refractive index of the reagent, allows researchers to use the Olympus FluoView FV1000®-MPE multiphoton microscope to collect images up to 4 mm beneath the surface. The result is detailed, crisp images captured deeper into contiguous tissue than was ever possible before.
The SCALEVIEW-A2 chemical reagent and SCALEVIEW 25x objective were designed to optimize imaging in small mammal brain tissue, but Miyawaki and his team say that it is possible to use the reagent to clarify other fixed tissues. In addition, the RIKEN team is working toward a system that may work on living tissue. Their initial results were published in Nature Neuroscience (www.nature.com/neuro/journal/vaop/ncurrent/full/nn.2928.html) in August 2011 and have since been covered in news media throughout the world.
Dr Miyawaki discussed the imaging breakthrough as one of the featured speakers at the 2nd annual Olympus Brain Imaging Symposium on Sunday November 13,held in conjunction with the Society for Neuroscience meeting in Washington DC. For more information or to register to see the symposium later via webcast, visit www.olympusamerica.com/neuro2011.
For more information on the SCALEVIEW-A2 reagent and the SCALEVIEW 25x objective, contact Brendan Brinkman, Olympus America Inc., phone +1 424-298-7402 or email brendan.brinkman@olympus.com.
