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Neuroscience Summer Seminar Series – Joseph Bergan joined by Eric Strieter
July 10, 2019 @ 12:00 pm - 1:00 pm
July 10, 2019, 12:00 p.m. – 1:00 p.m.
Tobin Hall Room 423
An in vitro platform for nanobody generation and molecular interrogation of intact neural circuits
It is possible to observe neural circuits deep inside tissue samples, revealing neuroanatomy with fine detail while also preserving the macroscopic organization of the intact brain. However, many powerful tools used to understand the molecular organization of biological tissues have been difficult to implement in samples that are larger than a few hundred microns. The biggest limitation hindering the application of techniques like immunohistochemistry to larger samples is that simple diffusion of large biomarkers is impractically slow. The Bergan lab (PBS) recently developed an approach that uses magnetohydrodynamic forces (MHD) to drive charged molecules, including fluorescently labeled antibodies, into tissue. This strategy facilitates the use of antibodies in large samples, but we see two areas for further improvement. First, the speed of antibody penetration increases with the concentration of antibody used but large amounts of traditional antibodies can be prohibitively expensive. Second, the speed of antibody penetration is limited by the large molecular weight (~150 kD) of traditional antibodies.
Nanobodies are single domain camelid antibodies that are roughly one tenth the size (~15 kD) of traditional antibodies. The small size and high charge-to-mass ratio, of nanobodies is ideal for MHD-based acceleration and should allow far more rapid staining in the intact brain. The Strieter lab (Chemistry) has developed a platform for rapidly producing nanobodies targeted to a wide variety of antigens at low cost and in large volume. A synthetic nanobody library displays roughly 108unique nanobody clones on the surface of yeast—allowing nanobody production without the need to immunize an animal. Candidate nanobodies can then be expressed recombinantly in large quantities, with product ready in as little as two weeks (start to finish). The goal of this collaboration is to generate an array of fluorescently labeled nanobodies to interrogate the 3D molecular organization of the brain. If successful, we will generate a nanobody toolkit designed to differentiate classes of neurons in the intact brain based on the neurotransmitters and cognate receptors they express.