A new technique called SWIFT (sacrificial writing into functional tissue) enables 3D printing of vascular channels into living matrices composed of stem-cell-derived organ building blocks (OBBs), yielding viable, organ-specific tissues with high cell density and function.
SWIFT involves a two-step process that begins with forming hundreds of thousands of stem-cell-derived aggregates into a dense, living matrix of OBBs that contains about 200 million cells per milliliter. Next, a vascular network through which oxygen and other nutrients can be delivered to the cells is embedded within the matrix by writing and removing a sacrificial ink.
The cellular aggregates used in the SWIFT method are derived from adult induced pluripotent stem cells, which are mixed with a tailored extracellular matrix (ECM) solution to make a living matrix that is compacted via centrifugation. At cold temperatures (0-4 °C), the dense matrix has the consistency of mayonnaise – soft enough to manipulate without damaging the cells, but thick enough to hold its shape – making it the perfect medium for sacrificial 3D printing. Source