Harvard Scientists Develop Improved Method for 3D-Printed Organs

By Iliriana Bisha Tagani MD | Published on September 10, 2019
Reviewed By Gilmore Health | On: February 24, 2020

Researchers Create Better Technique to 3D-Print Organs

Scientists at Harvard’s Wyss Institute have revealed that they have developed an improved method for 3D-printing of organs. This appears to be an exciting news for numerous people in need of an organ transplant.

Organs 3D Printing

This new technique, which is called the SWIFT method, was disclosed in a paper recently published in Science Advances.

While there appear to be more transplants being carried out annually today, the number of patients on the waiting list is quite high. Only roughly 1 in every 5 persons in need of a transplant is able to get it.

The estimate has it that 20 patients die every day in the United States while waiting for an organ transplant.

Artificial organs are seen as the hope of many people who are on the long waiting list for transplants. But these are often too small to be used in humans. Also, the organs lack efficient means of circulating oxygen.

The new technique represents an improvement on previous lab-grown organs. It takes 3D-printed organs, which are still in their early stages, to a new level.

“This is an entirely new paradigm for tissue fabrication,” paper co-author Mark Skylar-Scott said.

The Wyss Institute Research Associate explained that the aim with the SWIFT method was not to print an entire organ’s worth of cells. The technique focuses more on printing only vessels needed to support “a living construct that contains large quantities of OBBs.” OBBs stands for organ building blocks, derived from stem cells.

Lab-grown organs that use this method may help correct human organ issues with patients’ own cells.

The SWIFT method

SWIFT is an acronym for Sacrificial Writing Into Functional Tissue. The method helps to overcome a major challenge with 3D-printed human tissues: cellular density and organ-level function issue.

It enables 3D-printing of vascular channels for organ-specific tissues showing impressive cell density and function.

This technique involves two major steps. The first is the formation of a dense, living OBB matrix having roughly 200 million cells per milliliter from cellular aggregates. The second step involves the embedding of a vascular network within the matrix, achieved by writing a sacrificial ink and then removing it.

This artificial vascular network functioned as regular blood vessels in humans, helping to transport oxygen and nutrients to cells.

The cellular aggregates that formed the dense matrix developed by the Harvard scientists were obtained from adult induced pluripotent stem cells. These were mixed with a special extracellular matrix solution.

The living matrix became considerably soft to enable easy manipulation without cellular damage, but still sufficiently thick to retain its shape at cold temperatures. It turned more solid as temperatures rose to 37 degrees Celsius.

Mimicking human heart

Organ-specific tissues printed with vascular channels using this method and perfused with oxygenated media exhibited somewhat similar behavior as that of a human heart. However, artificial tissues that lacked the channels experienced cell death within 12 hours.

The Harvard scientists were able to demonstrate that cardiac tissues formed using the SWIFT method beat more synchronously and became more than 20 times stronger over a week period. The effects were similar to the features of a human heart.

“Forming a dense matrix from these OBBs kills two birds with one stone: not only does it achieve a high cellular density akin to that of human organs, but the matrix’s viscosity also enables printing of a pervasive network of perfusable channels within it to mimic the blood vessels that support human organs,” explained Sebastien Uzel, a lead author and Research Associate at the Wyss Institute.

The scientists expressed a belief that the SWIFT method will help revolutionize the field of organ engineering.

There are ongoing collaborations to investigate host integration of these grown tissues using animal models.