Sounds like the idea is to coat the insides of the hollow scaffold? Can’t rule anything out. I just suggested the cordial cherry approach as one being rather straightforward if the time factor can be controlled. The filler just oozes out.
My desktop 3d printer is slow and uses non-biological materials, but it can take an hour or more to print a small object in the approximately 8x8x8 print envelope. That time wouldn’t work too well in your field.
I understand the brain is toast if not oxygenated withing 7 minutes (or less) and other organs probably have similar deadlines. But expensive three-dee printers work faster and larger and your cherry solution is not out of range in terms of those 3dee printers’ time constraints (as far as I can see).
When you get the tissue deposition worked out, let me know. I want to print Salma Hayek. (And I am single.)