October 1, 2015

An accessible approach to making a mini-brain

A bundle of neurons
A bioengineering team at Brown University can grow “mini-brains”
of neurons and supporting cells that form networks and are electrically active.
Image: Hoffman-Kim lab/Brown University

(October 1, 2015)  In a new paper in Tissue Engineering: Part C, Brown University researchers describe a relatively accessible method for making a working – though not thinking – sphere of central nervous system tissue. The advance could provide an inexpensive and easy-to-make 3-D testbed for biomedical research.

If you need a working miniature brain — say for drug testing, to test neural tissue transplants, or to experiment with how stem cells work — a new paper describes how to build one with what the Brown University authors say is relative ease and low expense. The little balls of brain aren’t performing any cogitation, but they produce electrical signals and form their own neural connections — synapses — making them readily producible testbeds for neuroscience research, the authors said.

“We think of this as a way to have a better in vitro [lab] model that can maybe reduce animal use,” said graduate student Molly Boutin, co-lead author of the new paper in the journal Tissue Engineering: Part C. “A lot of the work that’s done right now is in two-dimensional culture, but this is an alternative that is much more relevant to the in vivo [living] scenario.”

Just a small sample of living tissue from a single rodent can make thousands of mini-brains, the researchers said. The recipe involves isolating and concentrating the desired cells with some centrifuge steps and using that refined sample to seed the cell culture in medium in an agarose spherical mold.

A little ball of brain
Three-dimensional tissues allow for more realistic experiments
than two-dimensional ones.

The mini-brains, about a third of a millimeter in diameter, are not the first or the most sophisticated working cell cultures of a central nervous system, the researchers acknowledged, but they require fewer steps to make and they use more readily available materials.

“The materials are easy to get and the mini-brains are simple to make,” said co-lead author Yu-Ting Dingle, who earned her Ph.D. at Brown in May 2015. She compared them to retail 3-D printers which have proliferated in recent years, bringing that once-rare technology to more of a mass market. “We could allow all kinds of labs to do this research.”

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