Tissue engineers have successfully grown artificial muscles, livers, kidneys, and skin, but there has been no reliable way to engineer precisely patterned networks of blood vessels. Without a vascular network to deliver nutrients, any artificial tissue cannot function.
MIT engineers built a human blood vessel on a chip: a central artery made from human endothelial cells embedded in a gel containing a small magnet. By jostling the gel back and forth with an external magnet, they stimulated the artery to sprout new capillaries.
The simple mechanical action of repeatedly jostling the artery stimulated it to grow smaller capillary branches. By changing the direction of the stretch, the researchers could redirect where new vessels grew. Varying the degree of stretch influenced how many new vessels sprouted.
Their results, reported in the Proceedings of the National Academy of Sciences, offer a new way to engineer artificial blood vessels and program the patterns in which they grow. The method is more precise than 3D printing for producing fine capillary networks.
The ability to program blood vessel growth with physical cues may enable reproducible fabrication of engineered tissues that can be implanted in the body to restore function after disease or injury.
Key insight: MIT engineers grew artificial blood vessels by mechanically stretching them with magnets, achieving precise control over capillary patterns; the method is more scalable than 3D printing for vascular networks; published in PNAS.