This week: Biomedical engineering division, University of Minnesota

Three-dimensional or 3D printing technology, which has been around for almost three decades, routinely makes headlines. Not surprising, given that the so-called Fabbers, or personal manufacturing machines—3D printers come under this category—now not only make jewellery and toothbrushes, but also football boots, racing-car parts, custom-designed cakes, guns, human organs, houses and plane parts.

3D printing can be used to save lives too. Consider this. During a heart attack, the muscle cells of the heart do not get enough blood. Hence, they die. Our bodies can’t replace these dead cells, so the body leaves a scar tissue in that area of the heart. This puts the person at risk of heart failure in the future.

A team of biomedical engineering researchers, led by the University of Minnesota (, has created a laser 3D-bioprinted patch to address the issue and help heal the scarred heart tissue after a heart attack. Three-dimensional bioprinting is the process of creating cell patterns in a confined space using 3D printing technologies.

The researchers successfully used this technique to incorporate stem cells (cells capable of renewing themselves through cell division, sometimes after long periods of inactivity) derived from adult human heart cells in a dish in the lab.

When the cell patch was placed on a mouse following a simulated heart attack, the researchers saw significant increase in functional capacity after just four weeks. Since the patch was made from stem cells and structural proteins (that do most of the work in cells and are required for the structure, function, and regulation of the body’s tissues and organs) belonging to the heart, it became part of the heart and was absorbed into the body, requiring no further surgeries.

The discovery, which is a major step forward in treating patients with tissue damage after a heart attack, was published on 14 April in Circulation Research, the journal published by the American Heart Association. The researchers have filed a patent for it.

The scientists insist that this research is different from previous ones in that the patch is modelled after a digital, 3D scan of the structural proteins of the heart tissue. The digital model is made into a physical structure by 3D printing, further integrating cardiac cell types derived from stem cells. Only with 3D printing of this type, explain the researchers, can we achieve the 1 micron resolution needed to mimic structures of native heart tissue.

The scientists say they are already beginning the next step to develop a larger patch that they will test on a pig heart, which is similar in size to a human heart. Of course, the real success will be known only when human trials take place.

3D printing belongs to a class of techniques known as additive manufacturing, or building objects layer by layer. The most common household 3D-printing process involves a “print head", which allows for any material to be extruded or squirted through a nozzle. There are several additive processes, including selective laser sintering, direct metal-laser sintering, fused deposition modelling, stereolithography and laminated-object manufacturing. All of them differ in the way layers are deposited to create the 3D objects.

Meanwhile, the concept of 4D printing, which allows materials to “self-assemble" into 3D structures, and was initially proposed by Skylar Tibbits of the Massachusetts Institute of Technology (MIT) in April 2013, is also showing promise.

Lab Watch is the Lounge guide to emerging tech from around the world .