Tissue engineers are already on the cusp of printing organs. But there’s one fundamental problem: It’s difficult to get tissue that’s either printed on a sheet or grown in a dish to become truly 3-D (like your heart or your liver). Researchers at the MIT-Harvard Division of Health Sciences and Technology (HST) think they have a way around that: They’ve invented a way of embedded living cells in tiny cubes, so that 3-D structures could be build in the same way that a kid would assemble a pile of Legos.
The researchers–Ali Khademhosseini and Javier Gomez Fernandez–call their new technique micromasonry, and have just published a paper on the technique. First, cells are encapsulated inside a common medical polymer called polyethylene glycol (PEG), which starts as a liquid but becomes a gel when illuminated. The cubes that result measure 100 to 500 millionths of a meter on a side. Then, they can be arranged like Lego bricks inside a tiny little template made of silicone. Once in the proper formation, the assembly is then recoated with the PEG and illuminated once again, so that everything binds together. The template is removed, et voila!
The technique is a far cry from the way bladders, cartilage, and other tissues have been built in labs: Usually, cells are built up on biodegradable scaffolds made of foam. The problem there is that they can”t match the real-life complexity of tissue. Printed tissues, meanwhile, rely on expensive equipment.
Gomez Fernandez and Khademhosseini think their process could be used to building something as complex as liver or heart tissue; they’ve already created tubes that could function as capillaries.