3D ‘bioprinting’ could help treat childhood heart defects and more

July 11, 2022 – Nearly one in 100 children in the United States is born with a heart defect. The effects can be devastating, forcing the child to rely on implanted devices that need to be changed over time.

“Mechanical solutions don’t grow with the patient,” says Mark Skylar-Scott, PhD, professor of bioengineering at Stanford University. “This means the patient will need multiple surgeries as they grow.”

He and his team are working on a solution that could give these children a better quality of life with fewer surgeries. Their idea: to use “3D bio-printers to make the tissues doctors need to help a patient.

“The dream is to be able to print heart tissue, such as heart valves and ventricles, that live and can grow with the patient,” says Skylar-Scott, who has spent the past 15 years working on bio-technology. print to create vessels and hearts. tissue.

The 3D printer for your body

Standard 3D printing works much like your desktop inkjet printer, but with one key difference: instead of spraying a single layer of ink onto paper, a 3D printer releases layers of molten plastic or other materials one at a time to build something from the bottom up. The result can be just about anything, from auto parts to entire homes.

Three-dimensional bioprinting, or the process of using living cells to create 3D structures such as skin, vessels, organs or bones, sounds like something out of a science fiction movie, but exists in made since 1988.

Where a 3D printer might rely on plastic or concrete, a bioprinter requires “elements like cells, DNA, microRNA, and other biological materials,” says Ibrahim Ozbolat, PhD, professor. of Engineering Science and Mechanics, Biomedical Engineering, and Neurosurgery at Penn State University.

“These materials are loaded into hydrogels so that the cells can remain viable and grow,” says Ozbolat. “This ‘bio-ink’ is then stratified and given time to mature into living tissue, which can take 3-4 weeks.”

What parts of the body have scientists been able to print so far? Most of the fabrics created by bioprinting to date are quite small – and nearly all of them are still in various stages of testing.

“Clinical trials have begun for ear cartilage reconstruction, nerve regeneration and skin regeneration,” says Ozbolat. “Over the next 5-10 years, we can expect more clinical trials with complex organ types.”

What is holding back bio-printing?

The problem with 3D bioprinting is that human organs are thick. It takes hundreds of millions of cells to print a single millimeter of tissue. Not only does this consume a lot of resources, but it also takes a huge amount of time. A bioprinter that expelled single cells at a time would need several weeks to produce even a few millimeters of tissue.

But Skylar-Scott and his team recently achieved a breakthrough that could help cut manufacturing time dramatically.

Instead of working with single cells, Skylar-Scott’s team successfully bioprinted with a group of stem cells called organoids. When multiple organoids are placed next to each other, they combine – similar to how grains of rice clump together. These clusters then self-assemble to create a network of tiny structures that look like miniature organs.

“Instead of printing individual cells, we can print with larger building blocks [the organoids]says Skylar-Scott. “We think it’s a faster way to make fabrics.”

As organoids speed up production, the next challenge for this kind of 3D bioprinting is having enough materials.

“Now that we can make things with lots of cells, we need lots of cells to train with,” Skylar-Scott says. How many cells are needed? He says “a typical scientist works with 1 to 2 million cells in a dish. To make a big, thick organ, you need 10 to 300 billion cells.

How bioprinting could change medicine

One of the visions of bioprinting is to create living heart tissue and whole organs for use in children. This could reduce the need for organ transplants and surgeries since living tissue would grow and function with the patient’s body.

But many issues need to be resolved before key body tissues can be printed and viable.

“Right now we’re thinking small instead of printing an entire heart,” says Skylar-Scott. Instead, they focus on smaller structures like valves and ventricles. And those structures, Skylar-Scott says, are at least 5 to 10 years old.

Meanwhile, Ozbolat envisions a world where doctors could bioprint exactly the structures they need while a patient is on the operating table. “It’s a technique where surgeons will be able to slide the impression directly onto the patient,” says Ozbolat. This fabric printing technology is in its infancy, but his team is dedicated to taking it further.