DNA Glues Particles Together

DNA base pairing can act as a smart glue to stick microparticles together to form colloidal gels. Researchers loaded a three-dimensional printer with DNA-coated particles to build soft, stable structures that could be used in tissue engineering (ACS Biomater. Sci. Eng. 2014, DOI: 10.1021/ab500026f).

DNA origami has taken advantage of the selectivity of DNA base pairing to construct nanosized and microscopic objects, such as smiley faces or maps of countries. However, these structures are usually invisible to the human eye and expensive to make. Andrew D. Ellington of the University of Texas, Austin, and his team wanted to go bigger.

They linked 2.3-μm-wide polystyrene particles to short strands of fluorescently labeled DNA then used the semisolid material to 3-D-print a pyramid a few millimeters in height underwater. When the DNA on the plastic particles is complementary, the resulting object resembles a foamy dollop. But if the strands cannot pair up, no structures form in the water.

The DNA glue strategy could allow researchers to 3-D-print structures for bioengineering because the gels form under conditions amenable to cell growth, Ellington says. In preliminary experiments, the researchers successfully grew human embryonic kidney cells within these 3-D-printed gels.

The centimeter-scale colloidal gels also serve as the “simplest, most direct demonstration” of DNA base pairing’s ability to organize larger objects, Ellington says.