The new device called 'BioP3' allows assembly of larger structures from small living microtissue components, researchers said, adding that future versions of BioP3 may finally make possible the manufacture of whole organs such as livers, pancreases or kidneys.
"In contrast to 3-D bioprinting that prints one small drop at a time, our approach is much faster because it uses pre-assembled living building parts with functional shapes and a thousand times more cells per part," said Jeffrey Morgan, a Brown University bioengineer.
In a new paper in the journal Tissue Engineering Part C, co-authored by Dr Andrew Blakely, a surgery fellow at Rhode Island Hospital, Morgan described the BioP3, made mostly from parts easily available for less than USD 200. The device seems at first glance to be a small, clear plastic box with two chambers: one side for storing the living building parts and one side where a larger structure can be built with them.
Above the box is a nozzle connected to some tubes and a microscope-like stage that allows an operator using knobs to precisely move it up, down, left, right, out and in. The plumbing in those tubes allows a peristaltic pump to create fluid suction through the nozzle's finely perforated membrane. That suction allows the nozzle to pick up, carry and release the living microtissues without doing any damage to them.
Once a living component has been picked, the operator can then move the head from the picking side to the placing side to deposit it precisely. In the paper, the team showed several different structures Blakely made including a stack of 16 donut rings and a stack of four honeycombs. Because these are living components, the stacked microtissues naturally fuse with each other to form a cohesive whole after a short time.
Each honeycomb slab had about 250,000 cells and the stack of four achieved a proof-of-concept, million-cell structure more than 2 millimetres thick. That's not nearly enough cells to make an organ such as a liver (an adult's has about 100 billion cells), Morgan said, but the stack did have a density of cells consistent with that of human organs. Complex stacks with many more cells are certainly attainable, Morgan said.
If properly nurtured, stacks of these larger structures could hypothetically continue to grow, Morgan said. The team has made structures with a variety of cell types including H35 liver cells, KGN ovarian cells, and even MCF-7 breast cancer cells.