Researchers at Harvard University's Wyss Institute for Biologically Inspired Engineering developed a new system that could allow for the self-assembly of organic structures. Self-assembly would allow disordered components to organize themselves without guidance from an external source. Developmental biology is guided by this fundamental principle. If researchers are able to develop this type of technology, 4-D printing could become a reality.
In the study, researchers created self-assembling hydrogel cubes. These hydrogel cubes are both biodegradable and biocompatible. Traditionally, many self-assembling hydrogel systems suffered from excessive "stickiness." However, researchers were able to overcome this challenge, allowing for selective adhesion. By coating each side of the hydrogel cubes with DNA strands, researchers were able to create gel bricks that only connected with the sides of cubes with the right "DNA glue."
Researchers were able to program chains of T-junctions, squares and fixed length shapes to self-assemble through the novel technique. Since cubes only bonded with other cubes with matching DNA, hydrogel bricks can be prompted to form a variety of different structures.
To create larger structures, researchers used smaller hydrogel cubes to act as connectors. Each connector cube was then coated with this "DNA glue." Once this was done, each connector cube was attached to one of the six sides of a larger hydrogel cube. These larger cubes would only bond to the cubes that had matching "DNA glue." Since these connector cubes could be placed on different faces of the larger hydrogel cubes, researchers were able to create a variety of unique shapes.