Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Researchers Find Gold Nanoparticles Capable of ‘Unzipping’ DNA

As the nanoparticles cluster together, they pull the strands of DNA apart.
As the nanoparticles cluster together, they pull the strands of DNA apart.

Abstract:
"Weakly Charged Cationic Nanoparticles Induce DNA Bending and Strand Separation"

Authors: Justin G. Railsback, Abhishek Singh, Ryan C. Pearce, Ramon Collazo, Zlatko Sitar, Yaroslava G. Yingling and Anatoli V. Melechko, North Carolina State University; Timothy E. McKnight, Oak Ridge National Laboratory

Published: online June 19, 2012 in Advanced Materials

Abstract: The understanding of interactions between double stranded DNA and charged nanoparticles will have a broad bearing on many important applications from drug delivery to DNA-templated metallization. Cationic nanoparticles can bind to DNA, a negatively charged molecule, through a combination of electrostatic attraction, groove binding, and intercalation. Such binding events induce changes in the conformation of a DNA strand. In nature DNA wraps around a cylindrical protein assembly (diameter and height of 6 nm ) with a ~220 positive charge , creating the complex known as chromatin. The charge of a nanoparticle plays a crucial role in its ability to induce DNA structural changes. If a nanoparticle has a highly positive surface charge density, the DNA is likely to wrap and bend upon binding to the nanoparticle (as in the case of chromatin). On the other hand, if a nanoparticle is weakly charged it will not induce dsDNA compaction. Consequently, there is a transition zone from extended to compact DNA conformations which depends on chemical nature of the nanoparticle and occurs for polycations with charges between 5 and 10. While the interactions between highly charged NP and DNA have been extensively studied, the processes occurring within the transition zone are less explored. In this paper, we investigate DNA interactions with weakly charged, ligand functionalized gold nanoparticles (AuNP) and show how binding events with these particles affect the structure of dsDNA. Our chosen AuNP has a 1.4 nm diameter gold core and thiolated alkane ligands bearing primary amines for a total charge of +6 per nanoparticle. The +6 charge permits exploration of DNA-NP molecular interactions in the transition zone. In silico observations showed a reversible and groove specific interaction of AuNPs with DNA and demonstrated that even weakly charged NPs could compromise structural integrity of dsDNA. Electrophoretic mobility indicated the existence of a nanoparticle-modified DNA structure either due to separation into single strands or compaction of DNA. Spectral analysis revealed that the structure of dsDNA with AuNPs is not completely denatured as it has a combination of double and single stranded regions. MD simulations showed that lone AuNPs cannot denature even a dsDNA oligomer, whereas high concentrations of AuNPs can bend and separate DNA strands. Specifically, hydrophobic agglomeration of NPs leads to intercalation of alkane moieties between DNA strands, disrupting Watson-Crick base pairing while charged groups hold and bend the DNA strands. By tuning and balancing charge and hydrophobicity one can envision nanoparticles engineered to evoke a specific structural response from DNA.

Researchers Find Gold Nanoparticles Capable of ‘Unzipping’ DNA

Raleigh, NC | Posted on June 20th, 2012

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 materials science and engineering 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 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.

"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.

The paper, "Weakly Charged Cationic Nanoparticles Induce DNA Bending and Strand Separation," was published online June 19 in Advanced Materials. Lead author on the paper is Justin Railsback, a master's student at NC State. Co-authors include Abhishek Singh and Ryan Pearce, Ph.D. students at NC State; Dr. Ramon Collazo, assistant professor at NC State; Timothy McKnight, of Oak Ridge National Laboratory; and Dr. Zlatko Sitar, Kobe Steel Distinguished Professor of Materials Science and Engineering at NC State. The research was supported by the National Science Foundation.

####

For more information, please click here

Contacts:
Matt Shipman
News Services
919.515.6386


Dr. Anatoli Melechko
919.515.8636


Dr. Yaroslava Yingling
919.513.2624

Copyright © North Carolina State University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Keysight Technologies Shifts to Direct Sales of High-Performance Products in North America March 3rd, 2015

Cambrios and Heraeus Jointly Create New, High-Conductivity Transparent Conductors: Two Companies' Combined Products Dramatically Extend Flexible Substrate Capabilities for Next-Generation Mass-Market Technology Products March 3rd, 2015

The taming of magnetic vortices: Unified theory for skyrmion-materials March 3rd, 2015

Democratizing synthetic biology: New method makes research cheaper, faster, and more accessible March 3rd, 2015

Laboratories

Researchers turn unzipped nanotubes into possible alternative for platinum: Aerogel catalyst shows promise for fuel cells March 2nd, 2015

First detailed microscopy evidence of bacteria at the lower size limit of life: Berkeley Lab research provides comprehensive description of ultra-small bacteria February 28th, 2015

Dendrite eraser: New electrolyte rids batteries of short-circuiting fibers: Solution enables a battery with both high efficiency & current density February 24th, 2015

Researchers synthesize material for efficient plasmonic devices in mid-infrared range February 16th, 2015

Govt.-Legislation/Regulation/Funding/Policy

The taming of magnetic vortices: Unified theory for skyrmion-materials March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

New nanodevice defeats drug resistance: Tiny particles embedded in gel can turn off drug-resistance genes, then release cancer drugs March 2nd, 2015

Forbidden quantum leaps possible with high-res spectroscopy March 2nd, 2015

Chip Technology

Cambrios and Heraeus Jointly Create New, High-Conductivity Transparent Conductors: Two Companies' Combined Products Dramatically Extend Flexible Substrate Capabilities for Next-Generation Mass-Market Technology Products March 3rd, 2015

The taming of magnetic vortices: Unified theory for skyrmion-materials March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

International research partnership tricks the light fantastic March 2nd, 2015

Nanomedicine

Democratizing synthetic biology: New method makes research cheaper, faster, and more accessible March 3rd, 2015

Pens filled with high-tech inks for do-it-yourself sensors March 3rd, 2015

New nanodevice defeats drug resistance: Tiny particles embedded in gel can turn off drug-resistance genes, then release cancer drugs March 2nd, 2015

New Hopes for Treatment of Intestine Cancer by Edible Nanodrug March 2nd, 2015

Discoveries

The taming of magnetic vortices: Unified theory for skyrmion-materials March 3rd, 2015

Democratizing synthetic biology: New method makes research cheaper, faster, and more accessible March 3rd, 2015

Pens filled with high-tech inks for do-it-yourself sensors March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Announcements

The taming of magnetic vortices: Unified theory for skyrmion-materials March 3rd, 2015

Democratizing synthetic biology: New method makes research cheaper, faster, and more accessible March 3rd, 2015

Pens filled with high-tech inks for do-it-yourself sensors March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Nanobiotechnology

Untangling DNA with a droplet of water, a pipet and a polymer: With the 'rolling droplet technique,' a DNA-injected water droplet rolls like a ball over a platelet, sticking the DNA to the plate surface February 27th, 2015

Bacteria network for food: Bacteria connect to each other and exchange nutrients February 23rd, 2015

Building tailor-made DNA nanotubes step by step: New, block-by-block assembly method could pave way for applications in opto-electronics, drug delivery February 23rd, 2015

Better batteries inspired by lowly snail shells: Biological molecules can latch onto nanoscale components and lock them into position to make high performing Li-ion battery electrodes, according to new research presented at the 59th annual meeting of the Biophysical Society February 12th, 2015

Research partnerships

Cambrios and Heraeus Jointly Create New, High-Conductivity Transparent Conductors: Two Companies' Combined Products Dramatically Extend Flexible Substrate Capabilities for Next-Generation Mass-Market Technology Products March 3rd, 2015

The taming of magnetic vortices: Unified theory for skyrmion-materials March 3rd, 2015

Breakthrough in OLED technology March 2nd, 2015

UC research partnership explores how to best harness solar power March 2nd, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE