Medical researchers are finding that 3D printers are providing them with a valuable tool that can help with vital research and new treatments. Scientists have already printed with bio-ink and printed living tissue material, and now newscientist.com have reported that Organovo in San Diego, California have 3D printed “mini livers”.
The mini-livers that Organovo produced are only half a millimetre deep and 4 millimetres across but they are able to perform many of the functions of the real thing. They believe that their system has the potential to create larger pieces of liver that could be used for transplant patients.
To produce the liver slices 3D printer builds up around 20 layers of hepatocytes and stellate cells, which are the main two of the types of cells found in a human liver. The machine functions with two print heads, one that lays down a scaffold and the other prints the cells into the shape of the liver organ. Cells from the lining of blood vessels are also added, which provides the liver cells with nutrients and oxygen. This means that the 3D printed liver tissue can survive for 5 days, compared to only 2 days for the “2D” single layers of cells which are used by researchers.
The mini-livers act in the same way as a full-size liver and can produce the key protein albumin, cholesterol, and the detoxification enzymes – cytochrome P450s which metabolizes drugs in the liver. This key enzyme allows the mini-livers to be used by researchers to monitor drug effectiveness as well as the progress of a disease after it has infected the liver.
Organovo unveiled their mini-livers at the annual Experimental Biology conference in Boston and are now working on printing larger networks of blood vessels so larger organs can be printed, ultimately leading to a full-sized human liver.