Each of the organs in the human body, such as the heart, is built from specialized cells that are held together by a biological scaffold called the extracellular matrix (ECM). This network of ECM proteins provides the structure and biochemical signals that cells need to carry out their normal function. However, until now it has not been possible to rebuild this complex ECM architecture using traditional biofabrication methods.
"What we've shown is that we can print pieces of the heart out of cells and collagen into parts that truly function, like a heart valve or a small beating ventricle," says Adam Feinberg, a professor of biomedical engineering (BME) and materials science & engineering at Carnegie Mellon, whose lab performed this work. "By using MRI data of a human heart, we were able to accurately reproduce patient-specific anatomical structure and 3D bioprint collagen and human heart cells."
"Collagen is an extremely desirable biomaterial to 3D print with because it makes up literally every single tissue in your body," explains Andrew Hudson, a BME Ph.D. student in Feinberg's lab and co-first author on the paper. "What makes it so hard to 3D print, however, is that it starts out as a fluid--so if you try to print this in air it just forms a puddle on your build platform. So we've developed a technique that prevents it from deforming."
The FRESH 3D bioprinting method developed in Feinberg's lab allows collagen to be deposited layer-by-layer within a support bath of gel, giving the collagen a chance to solidify in place before it is removed from the support bath. With FRESH, the support gel can be easily melted away by heating the gel from room temperature to body temperature after the print is complete.
This method is truly exciting for the field of 3D bioprinting because it allows collagen scaffolds to be printed at the large scale of human organs. And it is not limited to collagen, as a wide range of other soft gels including fibrin, alginate, and hyaluronic acid can be 3D bioprinted using the FRESH technique, providing a robust and adaptable tissue engineering platform. Importantly, the researchers also developed open-source designs so that nearly anyone, from medical labs to high school science classes, can build and have access to low-cost, high-performance 3D bioprinters.
COMPAMED-tradefair.com; Source: Carnegie Mellon University
