To mimic this architectural complexity in their engineered tissues, the
researchers embedded a mixture of brain cells taken from the primary
cortex of rats into sheets of hydrogel. They also included components of
the extracellular matrix, which provides structural support and helps
regulate cell behavior.
'Precisely Engineering 3-D Brain Tissues'
Those sheets were then stacked in layers,
which can be sealed together using light to crosslink hydrogels. By
covering layers of gels with plastic photomasks of varying shapes, the
researchers could control how much of the gel was exposed to light, thus
controlling the 3-D shape of the multilayer tissue construct.
, MIT News (2012)
"This brain isn't frozen," said Tiga-belas indignantly. "It's been
laminated. We stiffened it with celluprime and then we veneered it down,
about seven thousand layers. Each one has plastic of at least two
molecules thickness. This mouse can't spoil. As a matter of fact, this
mouse is going to keep on thinking forever. He won't think much, unless
we put the voltage on him, but he'll think. And he can't spoil..."
'Think Blue, Count Two', Cordwainer Smith (1963)