A team of researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University has found a way to self-assemble complex structures out of bricks smaller than a grain of salt. The self-assembly method could help solve one of the major challenges in tissue engineering: regrowing human tissue by injecting tiny components into the body that then self-assemble into larger, intricately structured, biocompatible scaffolds at an injury site.

The key to self-assembly was developing the world’s first programmable glue. The glue is made of DNA, and it directs specific bricks of a water-filled gel to stick only to each other, the scientists report in the September 9th online issue of Nature Communications.

"By using DNA glue to guide gel bricks to self-assemble, we’re creating sophisticated programmable architecture," says Peng Yin, Ph.D., a Core Faculty member at the Wyss Institute and senior coauthor of the study, who is also an Assistant Professor of Systems Biology at Harvard Medical School. This novel self-assembly method worked for gel bricks from as small as a speck of silt (30 microns diameter) to as large as a grain of sand (1 millimeter diameter), underscoring the method’s versatility.

The programmable DNA glue could also be used with other materials to create a variety of small, self-assembling devices, including lenses, reconfigurable microchips, and surgical glue that could knit together only the desired tissues, said Ali Khademhosseini, Ph.D., an Associate Faculty member at the Wyss Institute who is the other senior coauthor of the study.