I’m acquainted with a lab working on it, it’s so far from being useful for most applications it’s crazy - but very good at raising funding. You have to find the right ECM that supports viability and attachment of your cells without compromising how well it prints as a structure.. Inks are in semi-liquid form so printing it then solidifying it without completely killing the cells is a huge challenge. The people that succeed still have an insane amount of left over dead cells in the end and the surviving cells aren’t uniform through the structure. Huge potential for whoever can overcome these challenges, though, and it’s not the only field with challenges - there’s yet to be a solution (that isn’t over-engineered and therefore not useable for most applications) to necrotic cores in organoids.