As a layman I sort of lump icefish proteins under “cryoprotectants”, though I am not sure this is accurate—that might technically be reserved for penetrating antifreeze compounds.
The impression I have of the cryoprotectant toxicity problem is that we’ve already examined the small molecules that do the trick, and they are toxic in high (enough) concentrations over significant (enough) periods of time. Large molecules of a less toxic nature exist, but have a hard time passing through cell membranes, so they can’t protect the interior of cells very well.
M22 uses large molecules (analogous to the ice-blocking proteins found in nature—although these are actually polymers) to block ice formation on the outside of the cells (where there is a lower concentration of salts to start with), so a lower concentration of small-molecule CPAs are needed.
Another thing is that the different low-weight cryoprotective agents interact with each other somehow to block the toxicity effects—thus certain mixtures get better results than pure solutions. This seemingly suggests that other ways to block their toxicity mechanisms could also be found.
My current favorite idea is reprogramming the cells to produce large molecules that block ice formation—or which mitigate toxicity in cryoprotectants. We’re talking basically about gene therapy here, and that’s going to have complicated side effects, but not harder than some of the SENS proposals (e.g. WILT).
Another promising higher-tech idea is to use either bioengineered microbes or biomimetic nanotech (assuming that idea matures) to deliver large molecules to the insides of cells. Alternately, more rapid delivery and removal of small-molecule CPAs to reduce exposure time. In addition to this, reduced cooling times would be helpful, which makes me think of heat-conductive nanotech implants (CNTs maybe).
As a layman I sort of lump icefish proteins under “cryoprotectants”, though I am not sure this is accurate—that might technically be reserved for penetrating antifreeze compounds.
The impression I have of the cryoprotectant toxicity problem is that we’ve already examined the small molecules that do the trick, and they are toxic in high (enough) concentrations over significant (enough) periods of time. Large molecules of a less toxic nature exist, but have a hard time passing through cell membranes, so they can’t protect the interior of cells very well.
M22 uses large molecules (analogous to the ice-blocking proteins found in nature—although these are actually polymers) to block ice formation on the outside of the cells (where there is a lower concentration of salts to start with), so a lower concentration of small-molecule CPAs are needed.
Another thing is that the different low-weight cryoprotective agents interact with each other somehow to block the toxicity effects—thus certain mixtures get better results than pure solutions. This seemingly suggests that other ways to block their toxicity mechanisms could also be found.
My current favorite idea is reprogramming the cells to produce large molecules that block ice formation—or which mitigate toxicity in cryoprotectants. We’re talking basically about gene therapy here, and that’s going to have complicated side effects, but not harder than some of the SENS proposals (e.g. WILT).
Another promising higher-tech idea is to use either bioengineered microbes or biomimetic nanotech (assuming that idea matures) to deliver large molecules to the insides of cells. Alternately, more rapid delivery and removal of small-molecule CPAs to reduce exposure time. In addition to this, reduced cooling times would be helpful, which makes me think of heat-conductive nanotech implants (CNTs maybe).