"Printing Press" Method Stamps Out Gold Nanoparticles With New Properties

Process leads to a new kind of building block for assembling nanostructures with novel properties

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"Printing Press" Method Stamps Out Gold Nanoparticles With New Properties
Illustration: Thomas Edwardson

Gold nanoparticles have become a de facto do-it-all substance, with applications including cancer treatment and a number of electronics applications. If gold nanoparticles have become the go-to nanomaterial for myriad applications, then DNA has to be considered a key tool for generating patterns upon which effective nanomaterial designs are based. 

Now researchers at McGill University, in Montreal, Canada, have brought gold nanoparticles and DNA together in a new process that serves as a kind of printing press that makes it easier to replicate such designs.

In research published in the journal Nature Chemistry, the Canadian researchers employed the tried-and-true method of using strands of DNA as a scaffolding to organize nanoparticles. DNA strands are programmed to attract other strands so that they self-assemble into useful patterns. Each of these strands is attached to gold nanoparticles and assemblies are formed.

Unfortunately, repeating this process is time-intensive and costly. To overcome this problem, the McGill researchers developed a method that eliminates the need to wait for DNA structures to form on their own. At the end of each strand of DNA, there is a chemical that serves as a “sticky patch” that makes gold nanoparticles adhere when they come in contact with it. After a gold nanoparticle and the DNA structure are stuck together, the assembly is put into distilled water that separates the DNA structure from the nanoparticle but leaves behind an imprint of the DNA on the nanoparticle.

“These encoded gold nanoparticles are unprecedented in their information content,” said the paper’s senior author, Hanadi Sleiman, in a press release. Sleiman, who holds the Canada Research Chair in DNA Nanoscience, added that, “The DNA nanostructures, for their part, can be re-used, much like stamps in an old printing press.”

The researchers believe that this printing press method could usher in the use of DNA-encoded gold nanoparticles for a range of new applications because it enables new kinds of structures with as yet undetermined properties.

“In much the same way that atoms combine to form complex molecules, patterned DNA gold particles can connect to neighboring particles to form well-defined nanoparticle assemblies,” said Thomas Edwardson, another member of the research team, in a press release.

Some of the applications for which these new building blocks could yield significant advances, say the researchers, are optoelectronics and biomedicine.

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