Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH PUBLISHING
GLOBETECH PUBLISHING
PZ HTL SA

Synthetic Membrane Channels Constructed with DNA-Based Nanostructures

By BiotechDaily International staff writers
Posted on 28 Nov 2012
Scientists have shown for the first time that synthetic, lipid-membrane channels can be constructed by using a technique employing DNA molecules as building materials for custom-designed, self-assembling, nanometer-scale structures. The results suggest potential applications as molecular sensors, antimicrobial agents, and drivers of novel nanodevices.

Physicists at the Technical University of Munich (TUM; Garching, Germany) and the University of Michigan (Ann Arbor, MI, USA) have applied the emerging field of DNA-nanotechnology, including “scaffolded DNA origami,” to mimic the shape and function of one of the most widespread and important natural nanomachines – the biological transmembrane channel. The synthetic structure consists of a needle-like stem (42 nm long, 2 nm internal diameter) that penetrates and spans a lipid bilayer membrane. The stem is partly sheathed by a barrel-shaped cap that adheres to the membrane, in part via a ring of 26 cholesterol moieties around the edge of the cap that helps the device dock while the stem forms a channel. The device is formed by 54 double-helical DNA domains on a honeycomb lattice. Evidence is presented suggesting that these nanostructures function much like cellular ion channels. For example, in single-channel electrophysiological measurements there were similarities to natural ion channels, such as conductance on the order of 1 nanosiemens and channel gating.

"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, [...] forming a pore," explains Prof. Friedrich Simmel, co-coordinator of the Excellence Cluster Nanosystems Initiative Munich. Further experiments demonstrated that the resulting pores have electrical conductivity that suggests they could act like the voltage-controlled gates present in cells and that the transmembrane current could be tuned by adjusting fine structural details.

This study of the first artificial channel suggests 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 Prof. Hendrik Dietz, a fellow of the TUM Institute for Advanced Study. To test one potential application, the researchers used these devices as "nanopores" for several different molecular sensing experiments and confirmed that it is possible, by measuring changes in electrical characteristics, to record the passage of single molecules. 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 viruses or phages to kill targeted bacteria. Synthetic channels might be used as nanoneedles to inject material into cells for medical use such as gene-therapy or for basic studies of cell metabolism. Another idea is to harness the ion flux to drive sophisticated nanodevices.

The study was reported November 16, 2012, in the journal Science.

Related Links:
Technische Universitaet Muenchen
University of Michigan


Channels

Genomics/Proteomics

view channel
Image: The TheraCyte cell encapsulation device (Photo courtesy of TheraCyte, Inc.).

Encapsulated Human-Insulin-Producing Progenitor Cells Cure Diabetes in Mouse Model

A breakthrough system that allows subcutaneous implantation of encapsulated immature pancreatic cells (beta progenitor cells) was shown to produce enough insulin to correct the symptoms of diabetes in a mouse model.... Read more

Drug Discovery

view channel
Image: Chitosan is derived from the shells of shrimp and other sea crustaceans, including Alaskan pink shrimp, pictured here (Photo courtesy of NOAA - [US] National Oceanic and Atmospheric Administration).

Chitosan Treatment Clears the Way for Antibiotics to Eliminate Recurrent Urinary Tract Infections

Recurrent urinary tract infection was successfully resolved in a mouse model by treatment with the exfoliant chitosan followed by a round of antibiotics. Bacterial urinary tract infection (UTI), most... Read more

Biochemistry

view channel

Mitochondrial Cause of Aging Can Be Reversed

Researchers have found a cause of aging in lab animals that can be reversed, possibly providing an avenue for new treatments for age-related diseases including type 2 diabetes, cancer, muscle wasting, and inflammatory diseases. The researchers plan to begin human trials late 2014. The study, which was published December... Read more

Therapeutics

view channel

Cytokine Identified That Causes Mucositis in Cancer Therapy Patients

The action of the cytokine interleukin 1-beta (IL-1beta) has been found to underlie the onset of mucositis, a common, severe side effect of chemotherapy and irradiation of cancer patients. Mucositis occurs as a result of cell death in reaction to chemo- or radiotherapy. The mucosal lining of the mouth becomes thin, may... Read more

Business

view channel

Analytical Sciences Trade Fair Declared a Rousing Success

Organizers of this year's 24th "analytica" biosciences trade fair have reported significant increases in both the number of visitors and exhibitors compared to the 2012 event. The analytica trade fair for laboratory technology, analysis, and biotechnology has been held at the Munich (Germany) Trade Fair Center every... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.