Researchers Unveil Nanoparticle Construction Method

Researchers at Harvard Medical School, MIT, and the Wyss Institute for Biologically Inspired Engineering have discovered a new synthetic process to construct 3D metal nanoparticles using DNA as a mold, according to a study published in Science earlier this month.

By enabling the construction of nanoparticles in user-specified shapes out of materials like silver or gold, the breakthrough offers a range of applications in solar cells, disease detection, and laser technology.

“Using DNA as a nano-foundry, you can fabricate nanomaterials, 4,000 times smaller than a tiny paper sheet, as simple as growing something in your garden,” said lead author Wei Sun, a postdoctoral scholar in the Wyss' Molecular Systems Lab.

According to the Wyss Institute press release, the particles created were as small as 25 nanometers. A sheet of paper is approximately 100,000 nanometers thick.

“A really important question that was unanswered for years was how do you manipulate matter at all on the nanoscale,” said co-author and former Crimson news editor Amy Guan '12.  “[The research] is important because it shows a very elegant approach to creating the kind of shape you want.”

The process begins by using software to transfer the target shape into DNA mold design with a user-specified shape. Next, researchers use the mechanical simulation software to evaluate its mechanical properties. A gold seed is implanted within the mold and grows by absorbing a solution.

A useful analogy in understanding the process might be that of growing cube-shaped Japanese watermelons, in which watermelons are grown within a plexiglass container, according to the press release.

“Our nanocasting is based on similar consideration,” Sun said. “A nanoparticle seed is grown exclusively within the mold, which confines the nanoparticle final shape complementary to the cavity shape in the mold.”

This project has been important to Sun personally.

“I'm delighted to make the first demonstration of this strategy after years of working,” Sun wrote. “[But] we still need to keep working on this direction to merge the gap between what we have done in the lab and the requirements for future device applications.”