What do you mean by this? Is there any fundamental property of intelligence, physicality, or the universe, that you think wouldn't let this work?
Not if you remember to count all the computations being done by the quintillions of nanobots across the world known as "human cells."
That's not only inside cells, and not just neurons either. For example, your thyroid is busy brute-forcing the impossibly large space of antibody combinations, and putting every candidate cell-release through a very rigorous set of acceptance tests.