PHILADELPHIA Researchers are hopeful that new advances in tissue engineering and regenerative medicine could one day make a replacement liver from a patient's own cells, or animal muscle tissue that could be cut into steaks without ever being inside a cow. Bioengineers can already make 2D structures out of many kinds of tissue, but one of the major roadblocks to making the jump to 3D is keeping the cells within large structures from suffocating; organs have complicated 3D blood vessel networks that are still impossible to recreate in the laboratory.
Now, University of Pennsylvania researchers have developed an innovative solution to this perfusion problem: they've shown that 3D printed templates of filament networks can be used to rapidly create vasculature and improve the function of engineered living tissues.
The research was conducted by a team led by postdoctoral fellow Jordan S. Miller and Christopher S. Chen, the Skirkanich Professor of Innovation in the Department of Bioengineering at Penn, along with Sangeeta N. Bhatia, Wilson Professor at the Massachusetts Institute of Technology, and postdoctoral fellow Kelly R. Stevens in Bhatia's laboratory.
Their work was published in the journal Nature Materials.
Without a vascular system a highway for delivering nutrients and removing waste products living cells on the inside of a 3D tissue structure quickly die. Thin tissues grown from a few layers of cells don't have this problem, as all of the cells have direct access to nutrients and oxygen. Bioengineers have therefore explored 3D printing as a way to prototype tissues containing large volumes of living cells.
The most commonly explored techniques are layer-by-layer fabrication, or bioprinting, where single layers or droplets of cells and gel are created and then assembled together one drop at a time, somewhat like building a stack of LEGOs.
Such "additive manufacturing" methods can make com
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University of Pennsylvania