Saturday, March 31, 2012

Nerve cells grow on nanocellulose

Over a period of two years the research group has been trying to get human to grow on nanocellulose.
“This has been a great challenge,” says Paul Gatenholm, Professor of Biopolymer Technology at Chalmers.? Until recently the cells were dying after a while, since we weren’t able to get them to adhere to the scaffold. But after many experiments we discovered a method to get them to attach to the scaffold by making it more positively charged. Now we have a stable method for cultivating nerve cells on nanocellulose.”
When the nerve cells finally attached to the scaffold they began to develop and generate contacts with one another, so-called synapses. A neural network of hundreds of cells was produced. The researchers can now use electrical impulses and chemical signal substances to generate nerve impulses, that spread through the network in much the same way as they do in the . They can also study how nerve cells react with other molecules, such as pharmaceuticals.
The researchers are trying to develop ?artificial brains”, which may open entirely new possibilities in brain research and health care, and eventually may lead to the development of biocomputers. Initially the group wants to investigate destruction of synapses between nerve cells, which is one of the earliest signs of Alzheimer’s disease. For example, they would like to cultivate nerve cells and study how cells react to the patients' spinal fluid.
In the future this method may be useful for testing various pharmaceutical candidates that could slow down the destruction of synapses.  In addition, it could provide a better alternative to experiments on animals within the field of in general.
The ability to cultivate nerve cells on nanocellulose is an important step ahead since there are many advantages to the material.
?Pores can be created in nanocellulose, which allows nerve cells to grow in a three-dimensional matrix. This makes it extra comfortable for the cells and creates a realistic cultivation environment that is more like a real brain compared with a three-dimensional cell cultivation well,” says Paul Gatenholm.
Paul Gatenholm says that there are a number of new biomedical applications for nanocellulose. He is currently also leading other projects that use the material, for example a project where researchers are using nanocellulose to develop cartilage to create artificial outer ears. His research group has previously developed artificial blood vessels made of nanocellulose, which are being evaluated in pre-clinical studies.
Research on new application areas for nanocellulose is of major strategic significance for Sweden. Several projects are financed by the Knut and Alice Wallenberg Foundation and being conducted in collaboration between Chalmers and KTH within the Wallenberg Wood Science Center, WWSC.
The results will be presented at the American Chemical Society Meeting in San Diego, 25 March.

Provided by Chalmer's University of Technology

Fuel cells show potential

Fuel cells are an efficient, low carbon energy technology that could enable to replace the petrol and diesel we currently use to power our cars and other vehicles. However, the commercial uptake of technologies has been hampered by high costs, a lack of specialised refuelling infrastructure and the limited durability of the fuel cells themselves.

One problem with PEM fuel cell durability is corrosion. This is particularly severe when the fuel cell is turned on or off and is caused by changes in electrode potential at the cathode, associated with the movement of the air/fuel boundary as hydrogen flows into or out from the anode. With repeated start-up/shutdown of the fuel cell, corrosion of the on which the is supported causes a gradual decrease in available catalyst surface area and consequently a decrease in performance.

In NPL research explained in Electrochemistry Communications, the novel reference electrodes were used to measure the variation in electrode potential across the active area of a 50cm2 fuel cell supplied by Johnson Matthey. What makes the new reference electrodes special is the way that they connect to the fuel cell. Conventional reference electrodes are connected at the sides of the cell, meaning that they can only really measure what's going on around the edges, but the NPL reference electrode connects through holes drilled into the end plates, allowing a measurement of potential to be made at numerous points along the cell anode or cathode.

The electrodes are numbered with respect to the flow of hydrogen through the cell and measurements are taken at each point during operation. The movement of the air/fuel boundary through the cell can be detected by spikes in electrode potential and this can be mapped from the measurements taken by the electrodes. From this data, researchers can determine where and when corrosion is most likely to take place and investigate ways to reduce it.

NPL's Gareth Hinds, who led the project, said: "We are confident that this technique can be successfully applied to a wide range of fuel cell performance and durability issues, enhancing fundamental understanding of the underlying mechanisms and facilitating significant improvements in fuel cell design."

This provides fuel cell researchers and manufacturers with a powerful new diagnostic tool in the drive towards improved fuel cell performance and durability, which is critical for commercialisation of this energy technology.

This research was funded through the National Measurement System.

More information: In situ mapping of electrode potential in a PEM fuel cell, Electrochemistry Communications 17, 26-29.

Provided by National Physical Laboratory

Researchers create more efficient hydrogen fuel cells

 Hydrogen fuel cells, like those found in some "green" vehicles, have a lot of promise as an alternative fuel source, but making them practical on a large scale requires them to be more efficient and cost effective.

A research team from the University of Central Florida may have found a way around both hurdles.

The majority of hydrogen fuel cells use catalysts made of a rare and expensive metal -- platinum. There are few alternatives because most elements can't endure the fuel cell's highly acidic solvents present in the reaction that converts hydrogen's chemical energy into electrical power. Only four elements can resist the corrosive process -- platinum, iridium, gold and palladium. The first two are rare and expensive, which makes them impractical for large-scale use. The other two don't do well with the chemical reaction.

UCF Professor Sergey Stolbov and postdoctoral research associate Marisol Alcántara Ortigoza focused on making gold and palladium better suited for the reaction.

They created a sandwich-like structure that layers cheaper and more abundant elements with gold and palladium and other elements to make it more effective.

The outer monoatomic layer (the top of the sandwich) is either palladium or gold. Below it is a layer that works to enhance the energy conversion rate but also acts to protect the catalyst from the acidic environment. These two layers reside on the bottom slice of the sandwich -- an inexpensive substrate (tungsten), which also plays a role in the stability of the catalyst.

"We are very encouraged by our first attempts that suggest that we can create two cost-effective and highly active palladium- and gold-based catalysts -for hydrogen fuel cells, a clean and renewable energy source," Stolbov said.

Stolbov's work was recently published in The Journal of Physical Chemistry Letters.

By creating these structures, more energy is converted, and because the more expensive and rare metals are not used, the cost could be significantly less.

Stolbov said experiments are needed to test their predictions, but he says the approach is quite reliable. He's already working with a group within the U.S. Department of Energy to determine whether the results can be duplicated and have potential for large-scale application.

If a way could be found to make hydrogen fuel cells practical and cost effective, vehicles that run on gasoline and contribute to the destruction of the ozone layer could become a thing of the past.

Story Source:

The above story is reprinted from materials provided by University of Central Florida.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Sergey Stolbov, Marisol Alcántara Ortigoza. Rational Design of Competitive Electrocatalysts for Hydrogen Fuel Cells. The Journal of Physical Chemistry Letters, 2012; 3 (4): 463 DOI: 10.1021/jz201551e

Nanopore: the Oxford story

The announcement caught many by surprise, with the prospect of shrinking today’s bulky DNA sequencers into tiny devices that could decode the building blocks of life in hours (even seconds) instead of days, being widely reported in the media.

The blogosphere was abuzz with the exciting possibilities such machines open up.

Yet perhaps it shouldn’t have come as such a surprise: the firm’s success is built on nearly a decade of basic research at Oxford University’s Department of Chemistry.

Professor Hagan Bayley moved to Oxford in October 2003 having already done considerable research into how tiny pores in a protein might be used to detect the molecules passing through them, work he continued to develop in his Oxford lab.

In 2005, with the backing of IP Group and the help of Isis Innovation, Hagan founded Oxford to commercialize his ideas.

"We were looking at sensing a wide range of molecules, but it was work we did at Oxford which showed, for the first time, that our nanopores could identify all four bases of DNA," Hagan explains.

"After that it made sense to shift the firm’s development into the area of DNA sequencing, a move which provided an impetus for many others to follow."

Conventional sequencing requires DNA samples to be amplified (which can introduce errors), cut to the right length, attached to a bead or surface and given a fluorescent tag which has to be read with expensive imaging equipment.

The pioneering approach developed by Hagan and his team was to eliminate tags and enable individual DNA bases to be snipped off a strand one by one and then fired through a nanopore. Each base disrupts an electric current passed across the nanopore by a different amount so the DNA base ‘letter’ (A, C, G or T) can be read.

"We found a modified pore that could clearly distinguish between the different bases," Hagan tells me, "but the big prize was strand sequencing – being able to pull a whole strand of DNA through a pore and read out the bases one at a time from that. It was work done at Oxford that first showed that this was possible."

Despite his role as the firm’s founder, a board member, and long-time scientific adviser, Hagan didn’t become its CEO; "my interest was always in the basic research" he says.

Instead, he continued to work with his team on the scientific challenges of understanding nanopores and what they can do, publishing papers that were useful to both the spinout and others interested in the potential of this emerging technology.

Yet the relationship remained a close one: former members of Hagan’s group would go on to play a significant role in the firm’s development as it grew from a small start-up to a company now employing 120 people.

Drawing on the basic research, Nanopore has been working hard for the last few years on creating the electronic hardware and software necessary to turn the nanopore concept into viable commercial devices. Its new MinION and GridION sequencers have already been hailed as ‘game-changing’ products on the road to cheaper, faster, more flexible DNA sequencing but this could be just the start, Hagan suggests: "we could see a high-throughput chip reading signals from hundreds of thousands of nanopores simultaneously, this could be very important for large-scale sequencing."

After a decade of working in this area Hagan believes it is now time for him to move on and find new avenues of research.

He believes that most new commercial exploitation opportunities come from basic research, and instead of research councils and universities trying to plan ‘pathways’ to new products and services: "the best way to do initial research is to find good motivated scientists, give them funding and time, and leave them alone."

Hagan tells me: "we need to make it simple for academics to form a company, don’t make them have to take a year out from their academic work or quit their university job to get things going." The support he received from Isis Innovation and others around the University indeed made spinning out a firm ‘relatively easy’. 

His message to funders and universities is that it’s how you treat your researchers that counts; support them and, in time, everyone will reap the rewards.

Provided by Oxford University (news : web)