Researchers find gold nanoparticles capable of 'unzipping' DNA

Jun 20, 2012
Positively-charged ligands on the nanoparticles attach to the DNA, 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. Credit: Yaroslava Yingling, North Carolina State University

New research from North Carolina State University finds that gold nanoparticles with a slight positive charge work collectively to unravel DNA's double helix. This finding has ramifications for gene therapy research and the emerging field of DNA-based electronics.

"We began this work with the goal of improving methods of packaging genetic material for use in gene therapy," says Dr. Anatoli Melechko, an associate professor of at NC State and co-author of a paper describing the research. Gene therapy is an approach for addressing certain medical conditions by modifying the DNA in relevant cells.

The research team introduced , approximately 1.5 in diameter, into a solution containing double-stranded DNA. The nanoparticles were coated with called . Some of the ligands held a positive charge, while others were hydrophobic – meaning they were repelled by water.

Because gold nanoparticles have a slight positive charge from the ligands, and DNA is always negatively charged, the DNA and nanoparticles are pulled together into complex packages. Credit: Yaroslava Yingling, North Carolina State University

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 the process is below:

This video is not supported by your browser at this time.

"We think gold nanoparticles still hold promise for gene therapy," says Dr. Yaroslava Yingling, an assistant professor of materials science and engineering at NC State and co-author of the paper. "But it's clear that we need to tailor the ligands, charge and chemistry of these materials to ensure the DNA's structural integrity is not compromised."

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.

Explore further: Pressure probing potential photoelectronic manufacturing compound

Related Stories

Metal sheets with DNA framework may enable nanocircuits

May 20, 2009

(PhysOrg.com) -- Using DNA not as a genetic material but as a structural support, Cornell researchers have created thin sheets of gold nanoparticles held together by strands of DNA. The work could prove useful ...

Improving catalysis

Jun 14, 2011

(PhysOrg.com) -- Cardiff University research may help to improve the way that metal nanoparticles are used in catalysis – the process of making chemical reactions go faster.

Recommended for you

Light pulses control graphene's electrical behavior

6 hours ago

Graphene, an ultrathin form of carbon with exceptional electrical, optical, and mechanical properties, has become a focus of research on a variety of potential uses. Now researchers at MIT have found a way to control how ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

kevinrtrs
1 / 5 (10) Jun 20, 2012
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.

Here we have a major problem in the inermost working of the cell when trying to duplicate a subset of biological functionality. Hence a lot of intelligence need to be applied to solve the issue at hand.
If this is the case in this otherwise relatively minor application, one has to question just how it would be possible for the whole cellular structure to come together BY CHANCE in order to form a living cell in the first place?
R_j_Summers
5 / 5 (4) Jun 20, 2012
I read the same piece you did and I didn't see anywhere in it the mention of "how it would be possible for the whole cellular structure to come together BY CHANCE in order to form a living cell in the first place?". You say "one has to question...", I agree, we need to question everything and abiogenesis is a fascinating topic for exploration...unless you fall back on either ID, which has been completely debunked or the absurd assertion "goddidit"...with magic. Our understanding of the universe is growing daily while our belief in the supernatural is steadily shrinking...it seems there are less places for god to hide than there use to be, the gaps are slowly shrinking. I notice you also say "relatively minor application" when speaking to DNA being used for nano sized electrical circuits and that is a gross understatement, the implications are immense. Your lack of vision along side your appeal to ignorance suggests your opinion is of little if any value.
Terriva
4 / 5 (2) Jun 20, 2012
Hence a lot of intelligence need to be applied to solve the issue at hand.
The spontaneous formation of life may not be so complex. For example, these droplets are running autonomously, they're collecting "food" from their environment and they're even able to find their way through maze to find it. Such a droplet will run, until the concentration of food inside and outside of droplet will get into equilibrium. Now you can imagine, such a droplet will "swallow" chemical, which will be able to split (hydrolyze) molecules of "food" in such a way, the droplet can cumulate the food for ever. Such a droplet will grow and divide after while spontaneously and it will outnumber other droplets, which didn't get this feature yet. A formation of life has begun...
Terriva
1 / 5 (1) Jun 20, 2012
IMO the first living forms were quite large, if not macroscopic from their very beginning. From perspective of dense aether model there are supporting indicia for this mechanism. The dense aether model is centric to the wavelength of CMBR, which represents the middle of the dimensional scale of the observable universe, where the effects of relativity compensate with quantum mechanics. The complexity of inorganic world is highest at this scale and the possibility of spontaneous transition into organic life is highest here. In particular, this mechanism requires the presence of both three physical phases of matter at the same moment and the tidal waves may provide the repetitive path for neverending motion and separation of droplets at place. In AWT the complexity of life and the anisotropy of temporal and spatial dimensions is based on the repetitive motion across mass/energy density gradients at place. The above model just provides mechanism for it.
El_Nose
not rated yet Jun 21, 2012
it is actually one of the prizes of science to come up with a way for life to originate. While i disagree with his argument -- science admits it has no idea how complex life emerged. But after it did, evolution theory kicks in and takes us to today.

It's a valid question. Science has no answer for the question.