As early as April this year, foreign media reported that scientists at Tel Aviv University in Israel used human biomaterials to print a miniature heart in 3D. American researchers now use their similar techniques to print out their own human heart. The organ was created by the Chicago-based biotechnology company BIOLIFE4D, led by Dr. Ravi Birla, chief scientist.
To begin this process, leukocytes obtained from human volunteers are transformed into induced pluripotent stem cells, which in turn are promoted to differentiate into various types of cardiomyocytes. They are mixed with nutrients and growth materials to form the company's proprietary bio-ink.
The ink is then extruded through a nozzle of a dedicated bioprinter and supporting a transparent matrix material. In this way, tiny hearts are built layer by layer, and the matrix temporarily keeps everything in the desired shape. This shape is based on an MRI scan of the volunteer heart.
The scientist then placed the print in a bioreactor to simulate conditions in the human body. This causes the cardiomyocytes to self-organize and fuse together to form a solid heart tissue. The result is a complete (although very small) human heart from which the matrix material can then be dissolved.
According to BIOLIFE4D, the bioprinted heart contains four internal chambers - just like the real one - and "copied some of the functional indicators compared to the full-size heart."
Scientists now hope that once the technology is further developed, it can be used to print full-size hearts and transplant them. Because the organ has "growth" from the patient's own cells, rejection of the immune system may not be a problem.