3D printers are already actively used to print hard replacement parts for people with skull damage, deformed trachea, and a few other conditions. Work is underway to be able to print soft, functional tissues that promote cellular growth and may one day be used to replace entire organs. At Carnegie Mellon’s Regenerative Biomaterials & Therapeutics Group researchers are using open-source hardware and software to print complex 3D structures out of soft proteins and polysaccharide hydrogels.
Hydrogels are an excellent biocompatible material that has been used extensively in all sorts of life science applications. Being soft and fragile does not lend nydrogels to layer-by-layer printing because, being similar to gelatin, they fall apart under strain. To overcome this challenge the Carnegie Mellon team developed their own technique that first prints a relatively strong supporting gel structure and then embeds the desired final product within it. The external gel helps keep everything together during the printing process, but to remove the final product the external gel is simply melted away by bringing it to body temperature. The actual structure of the printed components are copies of coronary arteries and embryo hearts imaged using MRI.
The technique may work well for applications in which an implant is placed into the body and the external shell allowed to melt away while the body’s own tissues integrate with the artificial ones. The team is already working on embedding living cardiac cells into the printed scaffold, potentially leading toward replacement tissue patches that can be used post cardiac infarcts.