Kate WilletteWhat if it were possible to replace lost neurons by combining superfast, individual-specific 3D printing with cellular therapy designed to promote axon growth? Turns out that it is possible.

This is another story about the holy grail of spinal cord injury repair: regeneration — the process by which cells of the spinal cord grow back again across the damaged section, or gap. During my own adult life, the prospect of regeneration has gone from “impossible, don’t even bother” to “oh wait, I see how this might work.” Since the 1970s, scientists struggling to repair damaged cords have faced a long and frustrating set of harsh surprises, with each small success revealing yet more obstacles to over¬come. Regeneration is not a project for the faint of heart or for those in a hurry — but it is marked with milestones like the one I’m about to describe.

In the February edition of the journal Nature Medicine, a team of research¬ers led by Dr. Mark Tuszynski reported that they’d found a