DNA is a huge, unwieldy molecule that researchers at North Carolina State University have been trying to package in more efficient ways to help improve gene therapies.
They’ve been using gold nanoparticles coated with ligands in their studies, but while performing experiments they discovered that the material can actually unzip DNA strands, a finding that may help advance all kinds of genetic research.
Some details from a NC State:
The research team introduced gold nanoparticles, approximately 1.5 nanometers in diameter, into a solution containing double-stranded DNA. The nanoparticles were coated with organic molecules called ligands. Some of the ligands held a positive charge, while others were hydrophobic – meaning they were repelled by water.
Because the gold nanoparticles had a slight positive charge from the ligands, and DNA is always negatively charged, the DNA and nanoparticles were pulled together into complex packages.
“However, we found that the DNA was actually being unzipped by the gold nanoparticles,” Melechko says. The positively-charged ligands on the nanoparticles attached to the DNA as predicted, but the hydrophobic ligands of the nanoparticles became tangled with each other. As this tangling pulled the nanoparticles into clusters, the nanoparticles pulled the DNA apart. Video of how the process works is available here.
The finding is also relevant to research on DNA-based electronics, which hopes to use DNA as a template for creating nanoelectronic circuits. Because some work in that field involves placing metal nanoparticles on DNA, this finding indicates that researchers will have to pay close attention to the characteristics of those nanoparticles – or risk undermining the structural integrity of the DNA.
Abstract in Advanced Materials: Weakly Charged Cationic Nanoparticles Induce DNA Bending and Strand Separation