Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Artificial cell gets light-powered nanopump for calcium ions

28.11.2002


Artificial cells, or liposomes, are a promising area in biotechnology and nanotechnology, and now they have a new power source. An experimental finding has revealed a new method for converting light to stored chemical energy within the cells.



A team headed by Arizona State University chemistry professors Thomas Moore and Devens Gust has developed a light-powered molecular pump that shuttles calcium ions through a phospholipid membrane – calcium ion pumping that resembles various key cellular activities in living organisms, but engineered to be powered by light through specially designed molecules.

The research is reported in the November 28 issue of the journal Nature by Ira M. Bennett, Hebe M. Vanegas Farfano, Federica Bogani, Alex Primak, Paul A. Liddell, Ana L. Moore, Thomas A. Moore and Gust from Arizona State University and Luis Otero, Leonides Sereno and Juana J. Silber from Universidad National de Rio Cuarto in Argentina.


Beginning with an artificial membrane composed of a bilayer of phopholipids (similar to the lipid bilayers that form the membranes of living cells), the team created "shuttle" molecules that were soluble inside the lipid layer of the membrane, but not in the water inside and outside the "cell." These molecules, through the addition or removal of electrons, bind calcium ions at the outside surface of the liposome (these ions are water soluble and not ordinarily able to enter the oily lipid environment of the membrane), take them across the membrane, and release them at the membrane’s inner surface. The ions, which cannot remain in the lipid environment, go to the water solution inside the cell, raising its concentration of calcium ions.

The operation is controlled by an "artificial reaction center" molecule (modeled after similar natural molecules used in the biological process of photosynthesis) which is directionally positioned across the membrane and donates and reabsorbs electrons at its opposite ends in response to light.

"The net result is the use of light energy to transfer calcium to the interior of the liposome," said Gust. "In lay terms, the shuttle molecule is like a taxicab that transports the calcium ion across town. The artificial reaction center is the engine that powers the taxicab, closing and opening its doors, and the light is the fuel that makes that happen."

In essence, light energy is transferred to the artificial reaction center molecule and is passed along and finally stored chemically in the increased concentration of calcium ions inside the artificial cell.

"The concentration of ions inside biological membranes is the central organizing feature of living cells, " explained Moore. "In living cells, if the key ions were allowed to come to equilibrium with their concentrations outside, then the cells would be dead. The cell requires the maintenance of an ion gradient across its borders to be considered a living cell. It’s of interest to us to explore ways to generate this gradient – to pump these ions across artificial cells. This way, from the standpoint of energetics, we can drive reactions that are unique to living cells."

In a basic sense, an ion pump in an artificial cell is like a powerplant that drives the cell’s "motor."

"This is an elaboration of a principle in biochemistry that underpins all bioenergetics," said Moore. "There’s a good analogy with electricity – you make a voltage difference across a wire and the electrons run down it and you can extract work from that. Voltage is electro-motive force. A membrane with a difference in chemical potential across it would be like two wires going to a motor."

What could such a cellular machine be used for?

"One of the ideas would be to take a liposome, which is a nano-scale device, and use it as a nanofactory," Gust said. "You could put chemicals inside it, they would undergo reactions, and then you would take out the products. If you’re going to do that, you need to have a way to transport the reactants into the liposome, and you need to have a way to transport the products back out--this kind of pump could, in principle, be used for that type of thing, with light as the controlling factor."

There are also a host of potential biomedical and other applications for both the specific and the general concept.

"In nature, there aren’t pumps for calcium that work like ours, but the pumping of calcium across membranes is a really important function in biology," Gust said. "In muscle function, for example, a large fraction of the energy that is used pushes calcium ions across membranes. It’s also important in vision, in nerve function…it’s important in almost everything.

"Calcium release across membranes also has some role, not yet completely understood, in immune response in rheumatoid arthritis. We were funded for part of this work by the Harrington Arthritis Center because of that. We were also funded by the Department of Energy because of the relevance of this in transferring solar into chemical energy."

Gust and Moore note that this project and related research efforts in nanotechnology at ASU are outgrowths of more than a decade of research work done at ASU’s Center for the Study of Early Events in Photosynthesis.

"The paradigms for nanotechnology almost all come from biology," said Moore. "The things we emulate are ready-built. We have to figure out how they work, take the basic principles out of them, throw away all the parts that are only important to evolutionary biology, and get down to the nuts and bolts, gears and wheels of how they work. As we have come to understand them, we can take these things and learn to adapt them for our own human purposes."


###
Sources: Devens Gust, 480-965-4430
Thomas Moore, 480-965-3308


James Hathaway | EurekAlert!

More articles from Life Sciences:

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

nachricht CWRU researchers find a chemical solution to shrink digital data storage
22.06.2017 | Case Western Reserve University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A new technique isolates neuronal activity during memory consolidation

22.06.2017 | Life Sciences

Plant inspiration could lead to flexible electronics

22.06.2017 | Materials Sciences

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>