Dr. Sergiu Pașcă

Of course, for me, what was particularly frustrating was that we couldn't go very far in development.

So think about the cerebral cortex, the outer layer of the brain that presumably makes us human.

It has multiple layers, a large diversity of neurons.

You know, it takes 27 weeks.

to make all those cells in the cortex, 27 weeks to make all those neurons.

And we're not even talking about glial cells, the supporting cells that are coming much later for several years afterwards.

But just making those cells takes about 27 weeks.

And it turns out, something that we discovered through experiments done in a dish, is that the timing of the development of those cells, it's actually recapitulated in a dish as well.

So if you keep the cells in a dish, they'll actually essentially develop at the same pace.

They're not like much faster.

And it's very difficult to keep neurons in a dish for 27 weeks to get all the neurons.

Essentially they peel off, you know, every time you start to move them to another plate, then at one point they just die.

And so then we thought, how about like never letting them to sit down on a surface?

How about just essentially aggregating them as balls of cells and then letting those float?

And in those early days, there was this amazing scientist from Japan, Yoshiki Sasai, who started doing really beautiful experiments where he was already moving some of these studies that he was doing of development in 3D culture.

So he showed you can make an optic cup, a part of the eye.

And so it was clear it was in the air, this revolution of actually moving cells from 2D flat cultures to 3D self-organizing.

And that actually unleashed amazing new properties of the cells.

So essentially all we did in those days is I ordered from Germany this plate

that were counterintuitively coded so the cells never stick, right?