Bioprinting
Using 3D Printing Technology to Print Organs and Tissue
Can replacement organs one day come from a printer? That's the ultimate goal of the institute's bioprinting program. Institute scientists were the first to create a laboratory-grown organ implanted into a human, but they quickly realized the need to scale up the manufacturing process.
Living tissues are composed of many cell types that are arranged in a very specific order. When engineering replacement tissues and organs in the lab, maintaining this order is essential to ensuring that the replacement tissues have the same function that original body parts have.
Because of the precision of printing, researchers at the Wake Forest Institute for Regenerative Medicine have been investigating the possibility printing tissues and organs. In their first efforts, they used an actual inkjet desktop printer that was modified to print cells into a 3D shape. Cells were placed in the wells of the ink cartridge and the printer was programmed to print them in a certain order. The printer is now part of the permanent collection of the National Museum of Health and Medicine.
In 2016, the institute announced success printing living tissue structures using a specialized 3D printer that its researchers designed over a decade. The scientists printed ear, bone and muscle structures that, when implanted in animals, matured into functional tissue and developed a system of blood vessels. These early results indicate that the printed structures have the right size, strength and function for use in humans. The series of experiments proved the feasibility of printing living tissue structures to replace injured or diseased tissue in patients.
Skin Printing
In the not too distant future, a bioprinter filled with a patient's own cells can be wheeled right to the bedside to treat large wounds or burns by printing skin, layer by layer, to begin the healing process. WFIRM scientists have created such a mobile skin bioprinting system -- the first of its kind -- that allows bi-layered skin to be printed directly into a wound. The mobility of the system and the ability to provide on-site management of extensive wounds by scanning and measuring them in order to deposit the cells directly where they are needed to create skin is what makes it so unique.
Affecting millions of Americans, chronic, large or non-healing wounds such as diabetic pressure ulcers are especially costly because they often require multiple treatments. It is also estimated that burn injuries account for 10-30 percent of combat casualties in conventional warfare for military personnel. The researchers demonstrated proof-of-concept of the system by printing skin directly onto pre-clinical models. The next step is to conduct a clinical trial in humans.
Quality Assurance
Using High-Powered Microscopes to Ensure the Effectiveness of Engineered Cells
High-powered microscopes are critical to the field of tissue engineering and regenerative medicine. Light microscopes, which use light to detect small objects, allow scientists to assess the size, shape and activity of engineered cells to ensure that they will function properly in the body. Light microscopy is also commonly used to visualize whole engineered tissues and organs.
Conofocal laser scanning microscopy is used to obtain high-resolution images of thick samples, including tissue. Using a process known as optical sectioning, the technology enables images to be acquired point-by-point and then reconstructed with a computer, which provides three-dimensional images.
Scanning electron microscopy uses electrons to create images of the tiny details on the surface of materials. The scanning electron microscope at the Wake Forest Institute for Regenerative Medicine is specially designed to investigate biological specimens such as scaffolds and engineered tissue. Because scanning electron microscopy provides images that greatly exceed the magnification of conventional microscopes, this technology allows us to view scaffolds intricately to determine if cells are adhering properly.
Testing Functionality
Organ Baths Test the Functionality of Engineered Tissue
Tissues and organs that are developed in the laboratory have to do more than simply look like the tissue and organs they will replace; they have to function like them as well. We utilize an organ bath, an experimental set-up, to test laboratory-engineered tissue. With organ bath experiments, we can study how our generated tissues respond to chemical agents and electrical impulses to ascertain whether their responses are normal.
In our organ baths, tissue is suspended in a temperature-controlled chamber. The tissue's contractile function is recorded on a computer. Through a comparison of the tissue's contraction and relaxation responses to that of normal tissue, we're able to assess the functionality of engineered tissue.