Physical models of organs and tissues have many uses in clinical medicine, particularly when preparing for challenging surgeries. Naturally, the heart is commonly modeled using 3D printing to most closely mimic the nuances of unique patient anatomies. This is useful when preparing for procedures such as mitral valve repairs, but typically this is accomplished using printers that lay down layers of hard plastic or rubber that mostly only replicate the shape of the heart. The elasticity, on the other hand, is very much unlike that of real human hearts. A team at Carnegie Mellon University has now managed to print a 3D model of a patient’s heart using alginate, derived from seaweed, that closely replicates how cardiac tissue actually feels. That means that cardiac surgeons can actually try performing their procedures on such models, cutting and suturing them in preparation for actual interventions. “We can now build a model that not only allows for visual planning, but allows for physical practice,” said Adam Feinberg, the team lead. “The surgeon can manipulate it and have it actually respond like real tissue, so that when they get into the operating site they’ve got an additional layer of realistic practice in that setting.” The team’s technique is called Freeform Reversible Embedding of Suspended Hydrogels (FRESH) technique, which we covered in the past. It relies on injecting bioinks into a soft hydrogel, which is then melted away using heat to reveal the final objects made from the bioinks. In this latest development, FRESH was refined and expanded to build complete 1:1 mimics of actual patient hearts based on tomography data obtained from MRI scans. In addition to serving as physical models, tissues and organs printed using FRESH have the potential to host living cells. This can mean that highly realistic experimentation would be possible on model hearts that behave like real things, and of course this opens the potential for biosynthetic hearts built for transplantation. Source
