Daring AM: Wake Forest’s 3D Printed Liver Tissue Bound for Space

August 1, 2024 by Vanesa Listek 3D Printing Featured Stories Government Medical 3D Printing North America Science & Technology Space 3D Printing

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Northrop Grumman‘s 21st resupply mission (NG-21) to the International Space Station (ISS) will launch 3D printed liver tissue into space to study how it behaves and functions in a microgravity environment. Led by regenerative medicine pioneer Anthony Atala and bioprinting expert James Yoo, along with their team at the Wake Forest Institute for Regenerative Medicine (WFIRM), the investigation will determine if the unique conditions of space can help improve the growth and development of these complex tissues.

Scheduled for launch on August 3, 2024, the NG-21 mission will deliver 920 kilograms of scientific experiments and supplies to the ISS. The 3D printed liver tissue project, supported by NASA, the ISS National Lab, and Redwire, the company that pioneered 3D printing in space, will evaluate how microgravity affects the formation and maintenance of vascularized liver tissue.

Team Winston, the first-place winner of NASA’s Vascular Tissue Challenge, used a chamber to hold the printed tissue and test perfusion. Image courtesy of Wake Forest Institute for Regenerative Medicine.

During an ISS webinar discussing upcoming investigations launching to the space station, Atala explained that the project builds on the success of the NASA Vascular Tissue Challenge, launched in 2016. This competition challenged scientists to create thick, vascularized tissues that could remain viable outside the body for at least 30 days. The challenge concluded in 2021, with two teams from Wake Forest emerging as winners and the first team receiving $300,000 along with the opportunity to advance its research aboard the ISS.

This preflight image shows A) Bioprinted vascularized construct with a gyroid design consisting of interconnected channels. B) Bioprinted human liver tissue construct. C) The tissue construct-containing flow chamber is connected to a perfusion system. Image courtesy of WFIRM.

Why the Liver?

The liver is a particularly challenging organ to replicate due to its large size, complex structure, and extensive vascular network. To address these challenges, WFIRM’s team used a digital light projection (DLP) printer to create 3D printed tissue blocks that closely mimic the liver’s natural architecture. The gyroid structure of the liver tissue was replicated with this technology, allowing for the inclusion of functional vascular channels. These structures were then seeded with cells to achieve long-term functionality, enabling the tissues to sustain themselves for extended periods.

Atala said that once the 3D printed liver tissue constructs reach space, they expect to learn more about how these tissues behave in a microgravity environment. Microgravity may improve the development and maturation of large bioprinted tissues and organs, which are difficult to maintain on Earth due to the challenges associated with vascularization. The researchers will have the chance to study the tissue construct in microgravity, which may cause changes in cell shape, size, volume, and adherence properties.

Designing the gyroid structure. Image courtesy of WFIRM.

Once in space

Dubbed Maturation of Vascularized Liver Tissue Construct in Zero Gravity (MVP Cell-07), the investigation bound for space includes 12 experiment modules, each containing three tissue samples. These modules are specialized containers equipped with systems for nutrient delivery, temperature control, and waste removal to ensure the tissue samples remain viable during the experiment. They will use the on-orbit MVP facility for environmental control. Developed by Techshot (now part of Redwire), the MVP facility went to the ISS aboard SpaceX CRS-14 in April 2018 and is used for conducting research projects, including those involving artificial gravity and environmental control for a wide range of sample types.

The Multi-use Variable-g Platform (MVP) facility houses up to 12 science modules. Image courtesy of Grant Vellinger, Redwire.

To start the experiment, the modules will be taken out of the powered carrier and opened so the crew can install fresh media bags. Once the modules are in the MVP facility and the automated pump timeline is initiated, the 36 tissue samples will be processed for ten days.

Six modules are configured in their Powered Carrier for ascent. The carrier helps perfuse media through the tissue while launched in a cold bag, maintaining approximately 37°C for the MVP Cell-07 investigation. Image courtesy of Grant Vellinger, Redwire.

On day 10, the 12 experiment modules will be removed from the MVP facility for a crew operation. The bio chambers with tissue samples will be taken out from 4 of the 12 modules, fixed, and placed in cold stowage. Samples will also be taken from the media collected from each tissue sample. Then, the media bags in the remaining eight modules will be replaced before re-installing in the MVP facility.

The Multi-use Variable-g Platform (MVP) Cell Experiment Module is shown. Twelve modules run, each housing three sample conditions for the MVP Cell-07 investigation. Image courtesy of Grant Vellinger, Redwire.

On day 20, four more bio chambers will be removed, fixed, and placed in cold stowage. Media samples will be collected in the remaining four modules, and fresh media bags will be replaced. On day 30, the final four bio chambers will be removed, fixed, and stored. This process will show the progression and development of the tissues at various time points in microgravity.

The Multi-use Variable-g Platform (MVP) can run with two different gravity conditions, ranging from microgravity to 2g. Image courtesy of Grant Vellinger, Redwire.

Conducting this experiment in space offers unique advantages. On Earth, gravity can cause uneven cell distribution within the printed tissue. However, in the microgravity environment of the ISS, cells can distribute more evenly, potentially leading to better tissue formation and functionality, indicates Atala.

Atala also explained that the primary goal of this investigation is to understand how microgravity influences the development and maintenance of functional tissue. Overall, this experiment will provide valuable information on how bioprinted tissues containing blood vessels behave in microgravity and whether capillary-like vasculatures develop into the engineered tissue.

As the team analyzes the liver tissue at various stages—10 days, 20 days, and 30 days—they will focus on genomic, transcriptomic, proteomic, and metabolomic levels. These analyses will help researchers understand how microgravity affects the liver tissue at multiple biological layers, from gene expression to protein production and metabolic changes, providing insights into how space conditions can improve tissue engineering techniques. The results may have deep implications for future tissue engineering in space, improved treatments for patients on Earth, and ensuring astronauts’ health on future long-duration space missions.

Potential Impact

“The ability to create tissues and organs has been a major advance in the field, and we really want to know how to accelerate that technology. We have a great team at WFIRM to bring this technology from bench to bedside,” pointed out Atala. “This element of space has given us an extra dimension that will help us manufacture tissues better on earth and will allow us to have better conditions that we believe help to lower cost, scale up the technology, and accelerate the delivery of these techs here on earth and hopefully in space.”

3D printing tissue. Image courtesy of WFIRM.

For decades, Atala and Yoo have been making significant strides at WFIRM in 3D printing tissues and organs. They have succeeded in creating different tissues, including blood vessels, heart valves, and even mini-organs, using bioprinting. One outstanding achievement is the development of lab-grown bladders that have been successfully implanted in patients. Their work aims to reduce the reliance on donor organs by creating functional, transplantable tissues and organs in the lab, pushing the boundaries of regenerative medicine and bioprinting.

NASA’s live launch coverage will begin at 11:10 a.m. EDT on Saturday, August 3, 2024, on NASA+, NASA Television, the NASA app, YouTube, and the agency’s website.