DNA used as velcro to form cells into 3D structures

One of the great hopes for stem cells is that they'll allow us to eventually replace injured or damaged tissues. But there's a big gap between the cells of stem cells and anything resembling an organ. Organs are complex, three-dimensional structures populated by multiple cell types. Getting a bunch of cells to form these structures is a significant challenge.

One idea has been to use 3D printers. With multiple print-heads and a protein polymer gel, it's possible to construct a rough approximation of the structure of a mature organ. Now, a team of California scientists has come up with an interesting alternative: use DNA as a sort of cellular velcro to get cells to stick to each other and form a complex, three-dimensional tissue.

The basic idea is pretty simple. If they have the appropriate sequences, individual DNA molecules will pair up to form a double helix. If you coat one cell type with a short DNA sequence and then a second cell type with the sequence's partner, the two cells will stick to each other. And it's possible to coat a cell's surface with DNA simply by adding a lipid molecule to the end of the DNA strand.