An innovative gel that forms a layer over teeth and then recruits calcium and phosphate ions from saliva to build new enamel has the potential to change dental treatment. To date, we don't have any way to regenerate the tough outer layer of enamel on our teeth as it erodes with age.
We have a pretty good idea how things work during development, it’s tricking those cells into the same process as a fully-formed organism that’s hard. Isolating and distributing the hormones in the right way. I think you’re underselling the complexity and scale of biology. We can’t just put a tiny camera and chemo-sensor inside a neuron and see what’s going on in real time and synthesize up a hundred thousand copies.