Zixie Liang, a Ph.D. candidate at Yale University, has received IFER funding for her project, "Developing a Functional 3D-Bioprinted Human Cardiac Ventricle for In Situ Modeling of Cardiac Fibrosis and Animal-Free Drug Testing." Cardiac fibrosis—the stiffening and scarring of heart tissue—disrupts the heart's architecture and reduces its pumping ability, ultimately leading to heart failure. Despite its clinical significance, progress in understanding and treating fibrosis has been limited by reliance on animal models, which are invasive, not human-relevant, and have failed to yield effective therapies. Zixie's research leverages TRACE, a novel 3D bioprinting method that creates human cardiac ventricles from iPSC-derived cardiomyocytes and cardiac fibroblasts. These bioprinted ventricles begin spontaneous contraction within two days and sustain synchronized function for over 11 weeks, responding predictably to pharmacologic stimuli. By incorporating fluorescent tracking of myofibroblast activation, her model enables real-time, non-invasive monitoring of fibrosis progression alongside functional decline. This fully human platform offers unprecedented insight into how heart cells coordinate fibrotic remodeling, providing a powerful tool for therapeutic testing while setting a new standard for ethical, animal-free cardiac research.