Could you have human regeneration similar to, say, Dr Who (minus sfx)?

Question

(Modified as per request)

What is the upper bound for whole-body adaptive regeneration?

This is not about how fast a cell can regenerate, but about whether the cells could house sufficient technology to effectively rebuild part or all of a person, regardless of timeframe.

Individual cells matter only in that you have to know enough about each cell to know when it is damaged, how it is damaged and whether you want to keep it. You don't want a cancerous tumour regenerating when you try and kill it, but you do want accidentally killed cells repaired and you do want the original cells in the cancer replaced.

Cells aren't enough. A knife to the heart, if it's sharp enough, could theoretically separate cells without killing them. The regenerative system has to recognize this and repair even though it's not cellular damage.

If cells go from oxygen starvation to oxygen overload, the mitochondria will shut the cells down. Again, not physical damage but needs fixing.

Nor is this about trivial replacement, but adaptive regeneration. If you're killed by some deadly toxin, there's not much point healing only to die again. So you modify the DNA, as noted below, to make the same form less likely.

Cells have numerous tiny cavities, vacuelles, which may once have housed DNA. Cells also generate an electrical field, which you could potentially modulate.

My main interest is in whether this is sufficient to house cooperative nanobots and a distributed computer for whole-body adaptive regeneration (ie: you change so as to oppose the cause of death, so don't get killed again), but there may be all kinds of other uses such as the body becoming a computer interface to the nervous system.

Factoring in that DNA is self-modifying, which complicates things, and the inherent simplicity of nanobots, there are limits.

On the other hand, with suitable error correction codes and suitable algorithms, if you could dismantle a cell and then rebuild it, shift calcium molecules, alter DNA, etc, according to the results of the computer, then the processes aren't impossible. Size constraints and energy budgets might make it impossible for humans, at least beyond a certain level.

So, the question is, what is that level?

Answer 1

Ants/bees/wasps are so dependant upon their colony that these colonies can be considered super-organisms comprised of many parts, much like how our bodies are comprised of many different cells and symbiotic bacteria. If an ant/bee/wasp is badly wounded the others haul it back to the nest/hive and eat it, recycling its biomass so that the colony can afford to replace it. The same thing happens in our bodies, dead/defunct cells are attacked and consumed by the immune system and the biomass gained from this is available for the production of new cells. Arguably insects are a lot faster at this than we are, in part because they're doing it on a much larger scale, so it stands to reason that if we were comprised of larger more modular components we too could regenerate that quickly.

Imagine a person comprised of a colony of organisms like fleshy golf balls with eight or so tendrils that can change their shape/colour like an octopus, inside the "body" there's a nest of pea sized baby golf-ball-octopus-things ready to eat any dead/damaged golf-ball-octopus-things so they can grow to full size and replace them. Maybe the "body" has a leathery outer covering made from the remains of dead golf-ball-octopus-things like how wasps use their dead to make their nests.

Edit: As I’ve said regeneration is basically a process of self-consumption and replacement, if humans were like axolotls we could fix an irreparably damaged limb by chopping it off and regrowing it, eating it isn’t strictly necessary but the materials/energy to regrow it need to come from somewhere. This process isn’t 100% efficient and it never will be, even if we have the means to completely recycle every molecule in our bodies it’s going to take a lot of energy to do that and a significant amount of that energy will become heat. So if you want to regenerate from wounds like Wolverine or The Doctor you’re going to need a body that can either cool down quickly or withstand a lot of heat, ideally both, and this body will require a tremendous amount of stored chemical energy.

If you think this sounds like a bomb waiting to happen, you're right!