An innovative bioprinter designed by a University of Alabama at Birmingham student is speeding tissue engineering and the manufacturing of human tissue for organ regeneration and replacement. Wesley LaBarge, a fifth-year PhD student in the Biomedical Engineering Department, developed the idea of speeding computer-controlled creation of human tissue.

"Previously, commercial bioprinters could build tissue only one spheroid at a time. This system's efficiency is 100 times greater," LaBarge says. "The new bioprinter can pick up numerous spheroids at one time and place them simultaneously on a matrix of pins."

The bioprinting process uses 3D cell aggregates, called spheroids, and growth factors without the use of scaffold material to create structures that imitate natural tissues. The required cells, such as kidney or skin cells, are taken from a patient and are cultivated to create stem cells specific to the patient. These stem cells are then used to make the spheroids which are loaded into the printer. Printed onto the pins a full layer at a time, the spheroids fuse together until there is a single tissue layer. The bioprinter is designed to build multiple layers of engineered tissue, depending on the desired dimensions needed.

Jay Zhang, MD, PhD

"This scaffold-free bioprinter is unique and can print large tissues," says Jianyi "Jay" Zhang, MD, PhD, Chair of the UAB Department of Biomedical Engineering, lead researcher and a corresponding author. "We will be able to build larger and more precise tissues more quickly with this method. We use the cell fusion feature where cells attach and fuse together. One cell becomes two, two cells become four and so forth, so we can have 100,000 cells fused together to fabricate or engineer the building blocks of the tissue."

Zhang's lab research focuses on proteins and cardiac stem cells. Currently, the researchers are examining the mechanisms of congestive heart failure and the development of therapy to prevent it. "We don't have good therapy to cure heart failure, but we can develop new approaches to prevent it from occurring," Zhang says. "When a patient suffers a heart attack and we are able to save him, the patient can develop severe heart contractile dysfunction followed by heart failure, which is irreversible. Today, caring for patients with that condition costs a trillion dollars a year worldwide. We want to study the mechanisms of heart failure and find out why the heart muscle fails to pump and support needed oxygen for the human body."

The engineered tissues produced by the new bioprinter are being used in the lab to determine new techniques to help prevent heart failure. "We are using an engineered, functional myocardium to examine the mechanism of heart failure, and we are developing technology to therapeutically treat and prevent heart failure," Zhang says. "We have also used it to examine the disease further in hopes that we will discover a drug that can help these patients. That is one major direction of our lab."

Zhang and his team are collaborating with Auburn University to use a high-yield magnet to enable them to see the mechanics of a beating heart. "We also want to understand cardiac muscle cell proliferation," Zhang says. "We want to examine why the myocyte muscle cells were not delivered to the organ system. We want to find the regulators that can turn off the muscle cell proliferation shortly after birth. If we succeed in finding these regulators, we can manipulate them to make the cells turn back the clock, reproduce and heal the damaged heart muscle."

Zhang says their goal is to fabricate a functional myocardium that runs completely by a computer so that there is no human error involved. "LaBarge and his team have completed the fabrication piece of this project," Zhang says. "Now we have to make everything automatic."