This illustration shows the fabrication process for the DNA-imprinted polymer nanoparticles. Image: McGill University.
This illustration shows the fabrication process for the DNA-imprinted polymer nanoparticles. Image: McGill University.

Researchers at McGill University in Canada have chemically imprinted polymer particles with DNA strands – a technique that could lead to new materials for applications ranging from biomedicine to the promising field of ‘soft robotics’.

In a paper published in Nature Chemistry, the researchers describe a method for creating asymmetrical polymer particles that bind together in a spatially defined manner, the way that atoms come together to make molecules.

Although polymers are used in everything from clothing and food packaging to 3D printing and electronics, most self-assembled polymer structures have been limited to symmetrical forms such as spherical or cylindrical shapes. Recently, however, scientists have focused on creating non-symmetrical polymer structures – such as ‘Janus’ particles with two different ‘faces’ – and they are starting to discover exciting new applications for these materials. These include robots made from soft, flexible structures that can change shape in response to external stimuli.

The method described in the Nature Chemistry paper “introduces a programmable level of organization that is currently difficult to attain in polymer chemistry,” says Hanadi Sleiman, professor of chemistry at McGill and senior author of the study. “Chemically copying the information contained in DNA nanostructures offers a powerful solution to the problem of size, shape and directional control for polymeric materials.”

The new study builds on a technique developed in 2013 by Sleiman’s research group to make nanoscale ‘cages’ from strands of DNA and stuff them with lipid-like polymer chains that fold up into a ball-shaped particle that can contain cargo such as drug molecules.

To take this nano-engineering a step further, Sleiman and her PhD student Tuan Trinh teamed up with colleagues at the University of Vermont and Texas A&M University at Qatar. Together, the researchers developed a method to imprint the polymer ball with DNA strands arranged in pre-designed orientations. The cages can then be undone, leaving behind DNA-imprinted polymer particles capable of self-assembling – much like DNA itself – in pre-designed patterns. Because the DNA cages are used as a ‘mold’ to build the polymer particle, the particle size and number of molecular units in the polymer can be precisely controlled, says Sleiman.

The asymmetrical polymer structures could eventually find use in a range of applications, the researchers say. Examples include multi-compartment polymer particles, with each compartment encapsulating a different drug that could be delivered using different stimuli at different times, and porous membranes that are asymmetric, so they direct molecules along specific paths to separate them.

This story is adapted from material from McGill University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.