4D Printing Technique Could Be Used to Develop 3D Printed Human Organs for Transplant Patients

Often, when someone receives a life-saving organ transplant, this unfortunately means that another person recently lost their own life to provide it. But there are many researchers currently working to develop fully functioning human organs that can be 3D printed, which will save the lives of people who need transplants without having to wait for years to get an organ that’s been donated from another person. A research team with the University of Alberta in Canada has taken this work a step further, and developed a 4D printing technique that could allow them to engineer products with a biological function – one step closer to 3D printed human organs.

The research team, which operates out of the university’s Ingenuity Lab, has successfully 3D printed a resin, made of carbon nanotubes, membrane proteins, and silver nanoparticles, that can split water molecules to generate hydrogen when it’s submerged in water and irradiated with UV light – just like a hydrogen fuel cell.

Anu Stella Mathews, the lead chemical engineer on the project, explained, “When you irradiate the protein inside with UV, it generates a proton, which reacts with the silver nanoparticles to split water and generate hydrogen. The bio-nano ink we designed relies on a combination of materials, stability and geometry that can be controlled inside an engineered space.”

Mathews and her team hope to 3D print objects that are able to mimic complex natural mechanisms, like processes inside the human body or photosynthesis. They recently published a study, titled “Bio nano ink for 4D printing membrane proteins,” in the journal RSC Advances; co-authors include Mathews, Sinoj Abraham, Surjith Kumar Kumaran, Jiaxin Fan, and former Ingenuity Lab director Carlo Montemagno.

“We have expanded the set of tools to enable the incorporation of biological function as an intrinsic property in the devices we print with a new class of light-curable bio-nano ink. We call it 4-D printing,” Mathews said.

“It is the first step towards tissue engineering.”

The researchers tested their concept by 3D printing a leaf out of ink and hydrogel, made of natural proteins that can retain water and are compatible with human tissue. When they submerged the leaf in water and shone a UV light through, this caused a reaction that made the leaf swell. These results show that it’s possible to print a functional biological molecule, which paves the way for printing a functional human organ. According to Mathews, there is also potential for their research to lead to 3D printing inexpensive but efficient fuel cells on a large scale.

Mathews believes that the human body would most likely accept a hydrogel organ, but the research team has only successfully 3D printed one part of an organ, so they have a long way to go before reaching their goal of 3D printing more functional molecules and joining them to create organs.

Mathews said, “We have stabilized one factor, which is among the thousands of factors.”

“We are very excited to make this finding that we believe to be the first step towards the journey of miles.”

According to Alberta Health, over 4,500 Albertans are waiting for life-saving transplants, with hundreds more hoping to receive tissue donations that will help improve their quality of life. Mathews believes that in the near future, thanks to technology like she and her fellow researchers are working on, physicians will be able to 3D print replacement body parts, like a knee meniscus, which the Ingenuity Lab is currently developing.

“We would print it with a material that has the mechanical properties that can withstand the pressure of the bones, as well as have some factors that can promote cell adhesion, all while preventing the body’s immune system from rejecting the meniscus. But this is only phase one of many,” said Mathews.

The meniscus is a crescent-shaped disc in the human knee, and can cause knee pain and even arthritis if it gets torn. It can be replaced with a meniscus tissue transplant, and using a 3D printed meniscus can help surgeons replace the disc faster. The Ingenuity Lab researchers created a 3D printable, flexible disc that replicates the shape of a human meniscus and is able to stand up under pressure from other surrounding bones, as well as “adhere to other cells in the body.”

Mathews said, “The common cells are liking the material … and growing in it.”

The researchers will now focus on applying pressure to the 3D printed meniscus and monitor how the disc replica would respond in a real human knee.

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