MIT Technology Review is reporting on work by a collaborative group from Harvard and MIT to develop a technique for motivating cells to self-assemble into structures that resemble normal tissues. The research may one day lead toward practical methods of growing replacement organs specifically engineered for individual patients.
From MIT Tech Review:
[Ali Khademhosseini, a bioengineer at Harvard Medical School –ed.] mixes cells into a solution of a biocompatible polymer called polyethylene glycol, then pours the mixture into molds shaped like blocks, stars, spheres, or any other shape. When exposed to a flash of light, the polymer blocks solidify. The living Legos can then be built up into more-complex structures and exposed to another flash of light that bonds them together. But assembly is painstaking: each block is only about a hundred micrometers across.
So Khademhosseini and a group of researchers at MIT and Harvard have come up with a simple two-step process to make the living Legos self-assemble. Their method, described in a paper published today in the Proceedings of the National Academy of Sciences, relies on the basic fact that water and oil don’t mix. When water is dropped into a pool of oil, it will form a sphere, the shape that minimizes its interaction with the oil, says Khademhosseini. The polymer building blocks are hydrophilic–they easily absorb water and resist interacting with oil. But they can’t change their shape, so when Khademhosseini places them in an agitating bath of mineral oil, the blocks clump together in order to minimize their contact with the oil. The polymer blocks, now assembled into branches, cubes, and other shapes, are bonded together with another flash of light. The organization of the resulting structures can be controlled by varying the shape and size of the building blocks and the agitation speed.
More at the MIT Technology Review…
Abstract in PNAS…
Image: Polymer building blocks studded with cells self-assemble into structures whose complexity mimics that of human tissues. The cross-shaped gel contains cells stained green; the rod-shaped gels, which are about 200 micrometers across, contain cells stained red. Credit: Ali Khademhosseini