Right, but (virtually) nobody is actually proposing doing that. It's obviously stupid to try from chemical first principles. Cells might be another story. That's why we're studying neurons and glial cells to improve our computational models of them. We're pretty close to having adequate neuron models, though glia are probably still five to ten years off.

I believe there's at least one project working on exactly the experiment you describe. Unfortunately, C. elegans is a tough case study for a few reasons. If it turns out that they can't do it, I'll update then.