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91社区 researchers have chemically imprinted polymer particles with DNA strands 鈥� a technique that could lead to new materials for applications ranging from biomedicine to the promising field of 鈥渟oft robotics.鈥�

In a study published in Nature Chemistry, the researchers describe a method to create 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 -- for example 鈥楯anus鈥� particles with two different 鈥榝aces鈥� -- and they are starting to discover exciting new applications for these materials. One example: robotics made with soft, flexible structures that can change shape in response to external stimuli.听

The method described in the Nature Chemistry paper 鈥渋ntroduces a programmable level of organization that is currently difficult to attain in polymer chemistry,鈥� says 91社区 Chemistry professor Hanadi Sleiman, senior author of the study. 鈥淐hemically copying the information contained in DNA nanostructures offers a powerful solution to the problem of size, shape and directional control for polymeric materials.鈥�

Using DNA cages as molds

The new study builds on by Sleiman鈥檚 research group to make nanoscale 鈥渃ages鈥� from strands of DNA, and stuff them with lipid-like polymer chains that fold together into a ball-shaped particle that can contain cargo such as drug molecules.

To take that nano-engineering feat 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 鈥� much like DNA, itself 鈥� in pre-designed patterns. Because the DNA cages are used as a 鈥榤old鈥� to build the polymer particle, the particle size and number of molecular units in the polymer can be precisely controlled, says Sleiman, who holds the Canada Research Chair in DNA Nanoscience.

The asymmetrical polymer structures could be used eventually in a range of applications, the researchers say.听 One potential example: multi-compartment polymer particles, with each compartment encapsulating a different drug that could be delivered using different stimuli at different times. Another possibility: porous membranes that are asymmetric, so they direct molecules along specific paths to separate then.

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Funding for the research was provided by the Natural Sciences and Engineering Research Council of Canada, the Canadian Institutes for Health Research, the Centre for Self-Assembled Chemical Structures, the Qatar Research Foundation, and the Canada Research Chairs Program.

鈥淒NA-imprinted polymer nanoparticles with monodispersity and prescribed DNA-strand patterns,鈥� Tuan Trinh et al, Nature Chemistry, published online Dec. 4, 2017

:听Researchers at 91社区, the University of Vermont and Texas A&M University in Qatar have developed a method to chemically imprint polymer particles with DNA strands. This approach could lead to new materials for applications ranging from biomedicine to 鈥渟oft robotics.鈥� This computer simulation shows the first step of this process, in which the polymer chains associate together and fold inside the DNA cage.
CREDIT: The Li Research Group/University of Vermont

Contact:
Prof. Hanadi Sleiman
91社区, Department of Chemistry
hanadi.sleiman [at] mcgill.ca

Chris Chipello
Media Relations Office
514-398-4201
christopher.chipello [at] mcgill.ca

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