I think you could potentially (not in any way feasible with the current state of technology) design a different oxygen carrying protein than hemoglobin that only releases the oxygen in high pressure environments. But as you can't replenish them underwater, that will probably only buy you a few minutes at best rather than hours.
At any pressure a human underwater is likely to experience (besides perhaps being immediately transported to the bottom of the Mariana Trench) it is not practically the fluid/blood that is being compressed but tissues and gases, so barring a barometer it would be difficult to tell this new haemogolobin to hit release.
I’m sure you’re already are of the oxygen Haemoglobin dissociation Curve so O2-Hb release is already influenced by a number of forces that occur whilst holding your breath for ages (like increased CO2 causing decreased pH, increased DPG in oxygen poor tissues). What we would need is something that can carry a shit-ton more O2. So either a more efficient Hb molecule (could we get to 8 O2s?) or a way not to thicken a persons blood so much that they have a heart attack (the problem with just infusing more of the same stuff in)
IANAS, but I like to think that Yes, you can hold your breath longer with synthetic blood. Popular Mechanics covered this in 2006[1], an article I will never forget. But it's a speculative piece. More research has been done recently, a cursory google search for "synthetic blood" indicates many possibilities.
The usual problem for breath-holding is not lack of oxygen, but surplus of CO2. It is the latter that creates the panicked urge to breathe.
Free divers and stunt magicians therefore hyperventilate prior to diving, or getting sealed inside an ice block, or whatever. The disadvantage to this is that they then have no natural physiological gauge to determine when they are actually running low on oxygen, as the CO2 signal is delayed past the point where unconsciousness due to hypoxia occurs.
With artificial RBCs, you could perhaps load them up with an oxygen-storage protein like myoglobin instead of just oxygen-transporting hemoglobin, and use bicarbonate concentration as a trigger to release O2 and bind CO2--borrowing from both whales and crocodilians.
It might also be useful to develop an artificial lung or gill that employs perfluorodecalin flowing through narrow tubes of gas-permeable membrane to transport gases.
Red blood cells are more than bags of hemoglobin. The membrane is responsible for limiting the interaction of nitric oxide with hemoglobin, which deactivates the NO and causes vessel contraction. There may also be active release of NO by RBCs under hypoxic conditions, but I don't think we've proved that yet. This is interesting work, but a long way from being safe and practical.
If I am not completely mistaken, this opens up a whole new route for targeted treatments. Now the question is, how long does it take from diagnosis to the creation of a viable amount of synthetic blood for treatment? Say you have cancer and these cells carry a targeted anti cancer drug directly to the tumor (because they in turn need much oxygen). How long would it take from biopsy to having a liter or so of that stuff ready?
Wonder what impact that could eventually have on people with Sickle Cell or Beta thalassemia (or the rare case that hits the genetic jackpot and has both).
I don't follow medical tech religiously but read the original article and thought it relevant (I have a friend that actually has both conditions and the treatment for it is brutal).
I think gene therapy is going to solve that well before an approach like this. Those two are some of the lower hanging fruit to go after (well defined, clear mutation in a single gene, etc) and theres a bunch of therapies already in the pipeline to cure them.
Interesting process. Sounds like a microscopic version of moulding, then casting.
Wonder if they were able to make multiple synthetic cells from each original red blood cell, or if it was limited to a 1-to-1 thing in this initial working approach?
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[ 2.7 ms ] story [ 57.3 ms ] threadIn other words, I doubt it.
I’m sure you’re already are of the oxygen Haemoglobin dissociation Curve so O2-Hb release is already influenced by a number of forces that occur whilst holding your breath for ages (like increased CO2 causing decreased pH, increased DPG in oxygen poor tissues). What we would need is something that can carry a shit-ton more O2. So either a more efficient Hb molecule (could we get to 8 O2s?) or a way not to thicken a persons blood so much that they have a heart attack (the problem with just infusing more of the same stuff in)
[1] https://www.popularmechanics.com/science/health/a646/2713146...
Free divers and stunt magicians therefore hyperventilate prior to diving, or getting sealed inside an ice block, or whatever. The disadvantage to this is that they then have no natural physiological gauge to determine when they are actually running low on oxygen, as the CO2 signal is delayed past the point where unconsciousness due to hypoxia occurs.
With artificial RBCs, you could perhaps load them up with an oxygen-storage protein like myoglobin instead of just oxygen-transporting hemoglobin, and use bicarbonate concentration as a trigger to release O2 and bind CO2--borrowing from both whales and crocodilians.
It might also be useful to develop an artificial lung or gill that employs perfluorodecalin flowing through narrow tubes of gas-permeable membrane to transport gases.
Edit: Sorry, wrong link.
https://www.frontiersin.org/articles/10.3389/fphys.2018.0012...
Looks like I have more to read up on, thanks!
Wonder if they were able to make multiple synthetic cells from each original red blood cell, or if it was limited to a 1-to-1 thing in this initial working approach?