Featured Research

from universities, journals, and other organizations

Synthetic membrane channels built out of DNA: Nanotech structures mimic nature's way of tunneling through cell walls

Date:
November 20, 2012
Source:
Technische Universitaet Muenchen
Summary:
Physicists have shown that synthetic membrane channels can be constructed through "DNA nanotechnology." This technique employs DNA molecules as programmable building materials for custom-designed, self-assembling, nanometer-scale structures. The researchers present evidence that their nature-inspired nanostructures may also behave like biological ion channels. Their results could mark a step toward applications of synthetic membrane channels as molecular sensors, antimicrobial agents, and drivers of novel nanodevices.

This 3-D print shows the structure of a functional synthetic membrane channel constructed through DNA nanotechnology -- that is, using DNA molecules as programmable building materials for custom-designed, self-assembling nanometer-scale structures. This DNA-based membrane channel consists of a needle-like stem 42 nanometers long with an internal diameter of just two nanometers, partly sheathed by a barrel-shaped cap. A ring of cholesterol units around the edge of the cap helps the device "dock" to a lipid membrane while the stem sticks through it, forming a channel that appears capable of behaving like a biological ion channel. The device is formed by 54 double-helical DNA domains on a honeycomb lattice.
Credit: Dietz Lab, TU Muenchen; copyright TU Muenchen

As reported in the journal Science, physicists at the Technische Universitaet Muenchen (TUM) and the University of Michigan have shown that synthetic membrane channels can be constructed through "DNA nanotechnology." This technique employs DNA molecules as programmable building materials for custom-designed, self-assembling, nanometer-scale structures. The researchers present evidence that their nature-inspired nanostructures may also behave like biological ion channels. Their results could mark a step toward applications of synthetic membrane channels as molecular sensors, antimicrobial agents, and drivers of novel nanodevices.

Over the past three decades, researchers have advanced DNA nanotechnology from an intriguing idea to an emerging technology, with a toolbox of methods and a portfolio of nanometer-scale objects designed to demonstrate its potential. What's new here is the claim that DNA nanotech can be used to mimic one of the most widespread and important nanomachines in nature.

To wall off the insides of cells from the outside world, organisms in all three domains of life use the same kind of barrier: an impermeable membrane made from two layers of lipid molecules. Such membranes can also be found within cells, for example encapsulating the nucleus, and even surrounding many kinds of viruses. And to mediate between the different environments on either side of this universal barrier, nature provides a common type of passageway. Membrane channels are tube-like structures made of proteins, which pierce the barriers and regulate the two-way exchange of material and information between the inside and outside. Now researchers have demonstrated the first artificial membrane channel made entirely of DNA, and its characteristics suggest a number of potential applications. "If you want, for example, to inject something into a cell, you have to find a way to punch a hole into the cell membrane, and this device can do that, at least with model cell membranes," says TUM Prof. Hendrik Dietz, a fellow of the TUM Institute for Advanced Study.

In a shape inspired by a natural channel protein, the DNA-based membrane channel consists of a needle-like stem 42 nanometers long with an internal diameter of just two nanometers, partly sheathed by a barrel-shaped cap. A ring of cholesterol units around the edge of the cap helps the device "dock" to a lipid membrane while the stem sticks through it, forming a channel that appears to function like the real thing. TUM Professor Friedrich Simmel, co-coordinator of the Excellence Cluster Nanosystems Initiative Munich, explains: "We have not tested this yet with living cells, but experiments with lipid vesicles show that our synthetic device will bind to a bilayer lipid membrane in the right orientation, so that the stem both penetrates the membrane and holds at the surface, forming a pore."

Further experiments demonstrated that the resulting pores have electrical conductivity comparable to that of a natural cell wall with ion channels, suggesting that they might be able to act like voltage-controlled gates. The results also suggest that transmembrane current could be tuned by adjusting fine structural details of the synthetic channels. To test one potential application of the DNA nanotech devices, the researchers used them as "nanopores" for several different molecular sensing experiments. These confirmed that it is possible, by observing changes in the electrical characteristics, to record the passage of single molecules through synthetic membrane channels made from DNA. Because this approach allows both geometric and chemical tailoring of the membrane channels, it might offer advantages over two other families of molecular sensors, based on biological and solid-state nanopores respectively.

Other conceivable applications remain to be investigated. One notion is to imitate the action of viruses or phages, breaking through the cell walls of targeted bacteria to kill them. In gene therapy, synthetic membrane channels might be used as nano-needles to inject material into cells. Such channels could also be used in basic studies of cell metabolism. Another idea is to harness the so-called ion flux -- which in cell membranes moves material in and out through the channel -- to drive sophisticated nanodevices inspired by other natural mechanisms. "We might be able to mimic natural ion pumps, transport proteins, and rotary motors like the enzyme responsible for synthesizing ATP," says Dietz. "I love that idea. That's what keeps me running."


Story Source:

The above story is based on materials provided by Technische Universitaet Muenchen. Note: Materials may be edited for content and length.


Journal Reference:

  1. M. Langecker, V. Arnaut, T. G. Martin, J. List, S. Renner, M. Mayer, H. Dietz, F. C. Simmel. Synthetic Lipid Membrane Channels Formed by Designed DNA Nanostructures. Science, 2012; 338 (6109): 932 DOI: 10.1126/science.1225624

Cite This Page:

Technische Universitaet Muenchen. "Synthetic membrane channels built out of DNA: Nanotech structures mimic nature's way of tunneling through cell walls." ScienceDaily. ScienceDaily, 20 November 2012. <www.sciencedaily.com/releases/2012/11/121120122008.htm>.
Technische Universitaet Muenchen. (2012, November 20). Synthetic membrane channels built out of DNA: Nanotech structures mimic nature's way of tunneling through cell walls. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2012/11/121120122008.htm
Technische Universitaet Muenchen. "Synthetic membrane channels built out of DNA: Nanotech structures mimic nature's way of tunneling through cell walls." ScienceDaily. www.sciencedaily.com/releases/2012/11/121120122008.htm (accessed September 16, 2014).

Share This



More Matter & Energy News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Manufacturer Prints 3-D Car In Record Time

Manufacturer Prints 3-D Car In Record Time

Newsy (Sep. 15, 2014) — Automobile manufacturer Local Motors created a drivable electric car using a 3-D printer. Printing the body only took 44 hours. Video provided by Newsy
Powered by NewsLook.com
Refurbished New York Subway Tunnel Unveiled After Sandy Damage

Refurbished New York Subway Tunnel Unveiled After Sandy Damage

Reuters - US Online Video (Sep. 15, 2014) — New York officials unveil subway tunnels that were refurbished after Superstorm Sandy. Nathan Frandino reports. Video provided by Reuters
Powered by NewsLook.com
Frustration As Drone Industry Outpaces Regulation In U.S.

Frustration As Drone Industry Outpaces Regulation In U.S.

Newsy (Sep. 14, 2014) — U.S. firms worry they’re falling behind in the marketplace as the FAA considers how to regulate commercial drones. Video provided by Newsy
Powered by NewsLook.com
Smart Gun Innovators Fear Backlash From Gun Rights Advocates

Smart Gun Innovators Fear Backlash From Gun Rights Advocates

Newsy (Sep. 14, 2014) — Winners of a contest for smart gun design are asking not to be named after others in the industry received threats for marketing similar products. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins