This New Approach For 3D Printing Human Organs Brings Us Closer To Future Transplants

Scientists have copied the “lost wax” technique, used in producing renaissance bronzes, for 3D-printing mini version of human organs with their own blood vessels.

This is an advance which moves the field closer to making life-saving organ transplants; just in the US, there are over 100,000 people are waiting for transplants, 20 of them die each day.

In the past ten years, scientists have created mini-hearts, kidneys, and brains, called “organoids,” in laboratories for studying diseases such as heart attacks, cancer, and dementia.

However, those models are as small as a lentil due to a critical ceiling. Researchers cannot get the tubes mimicking blood vessels so they have struggled to get nutrients and oxygen into their core.

This limitation has prevented organoids from becoming full-sized transplant organs in the lab, tailor-made from the cells of the patient, not subject to rejection.

But now, researchers with the lead of Jennifer Lewis at Harvard University’s Wyss Institute for Biologically Inspired Engineering, have found an ingenious way to sculpt channels which meander like real blood vessels using mini-organs.

It even has its own name, SWIFT, short for Sacrificial Writing into Functional Tissue. First, they make building blocks for organs using human stem cells that are chemically cajoled into becoming mini-brains and hearts.

Then they mix hundreds of thousands of these blocks to generate a slurry, compacting it at a low temperature so as to form a cell matrix that’s almost as dense as the human tissue.

Next, the researchers use a 3D printer, a nozzle which contains an ink made of gelatin and red dye descends into the mixture, to deposit the contents through the matrix of cells according to a branch pattern that’s pre-ordained.

When the researchers have printed the network, the mix is heated to 37 degrees C. The ink melts and leaves channels that are lined with the endothelial cells in human vessels.

The last thing to do is perfusing the mini-organs using a nutrient and oxygen-rich liquid. With this method, the 1.5cm mini-heart beat for over a week on its own.

Sébastien Uzel, a co-author from the Wyss Institute says:

However, the researchers could not help adding some cadenzas to their feat. They injected a drug increasing human’s heart rate through the vessels. It immediately doubled the mini-heart rate. Additionally, the team made a wedge of heart tissue as well as 3D-printed a copy of the primary coronary artery along with one branch onto it, which could come handy for a heart transplant.

According to Donald Ingber, Found Director of Wyss Institute: