Credit: Collin Edington and Iris Lee, Department of Biomedical Engineering, MIT
Something pretty incredible happens—both visually and scientifically—when researchers spread neural stem cells onto a gel-like matrix in a lab dish and wait to see what happens. Gradually, the cells differentiate and self-assemble to form cohesive organoids that resemble miniature brains!
In this image of a mini-brain organoid, the center consists of a clump of neuronal bodies (magenta), surrounded by an intricate network of branching extensions (green) through which these cells relay information. Scattered throughout the mini-brain are star-shaped astrocytes (red) that serve as support cells.
Caption: Top down view of gut tissue monolayer grown on an engineered scaffold, which guides the cells into organized crypts structures similar to the conformation of crypts in the human colon. Areas between the circles represent the flat lumenal surface. Credit: Nancy Allbritton, University of North Carolina, Chapel Hill
When Nancy Allbritton was a child in Marksville, LA, she designed and built her own rabbit hutches. She also once took apart an old TV set to investigate the cathode ray tube inside before turning the wooden frame that housed the TV into a bookcase, which, by the way, she still has. Allbritton’s natural curiosity for how things work later inspired her to earn advanced degrees in medicine, medical engineering, and medical physics, while also honing her skills in cell biology and analytical chemistry.
Now, Allbritton applies her wide-ranging research background to design cutting-edge technologies in her lab at the University of North Carolina, Chapel Hill. In one of her boldest challenges yet, supported by a 2015 NIH Director’s Transformative Research Award, Allbritton and a multidisciplinary team of collaborators have set out to engineer a functional model of a large intestine, or colon, on a microfabricated chip about the size of a dime.
Credit: Ken Chan and Viviana Gradinaru Group, Caltech
What you are looking at above is something scientists couldn’t even dream of imaging less than a decade ago: bundles of neurons in the brainstem of an adult mouse. These bundles are randomly labeled with various colors that enable researchers to trace the course of each as it projects from the brainstem areas to other parts of the brain. Until recently, such a view would have been impossible because, like other organs, the brain is opaque and had to be sliced into thin, transparent sections of tissue to be examined under a light microscope. These sections forced a complex 3D structure to be visualized in 2D, losing critical detail about the connections.
But now, researchers have developed innovative approaches to make organs and other large volumes of tissue transparent when viewed with standard light microscopy . This particular image was made using the Passive CLARITY Technique, or PACT, developed by the NIH-supported lab of Viviana Gradinaru at the California Institute of Technology (Caltech), Pasadena. Gradinaru has been working on turning tissues transparent since 2010, starting as a graduate student in the lab of CLARITY developer and bioengineering pioneer Karl Deisseroth at Stanford University. PACT is her latest refinement of the concept.