Man-made synthetic pores mimic important features of natural pores

Man-made synthetic pores mimic important features of natural pores: The pores the scientists built are permeable to potassium ions and water, but not to other ions such as sodium and lithium ions...

To create the synthetic pores, the researchers developed a method to force donut-shaped molecules called rigid macrocycles to pile on top of one another. The scientists then stitched these stacks of molecules together using hydrogen bonding. The resulting structure was a nanotube with a pore less than a nanometer in diameter. "This nanotube can be viewed as a stack of many, many rings," said Xiao Cheng Zeng, University of Nebraska-Lincoln Ameritas University Professor of Chemistry, and one of the study's senior authors. "The rings come together through a process called self-assembly, and it's very precise. It's the first synthetic nanotube that has a very uniform diameter. It's actually a sub-nanometer tube. It's about 8.8 angstroms."

Scientists switch mouse's genes off and on with radio waves

Scientists switch mouse's genes off and on with radio waves: Friedman and his colleagues coated iron oxide nanoparticles with antibodies that bind to a modified version of the temperature-sensitive ion channel TRPV1, which sits on the surface of cells. They injected these particles into tumours grown under the skins of mice, then used the magnetic field generated by a device similar to a miniature magnetic-resonance-imaging machine to heat the nanoparticles with low-frequency radio waves. In turn, the nanoparticles heated the ion channel to its activation temperature of 42 °C. Opening the channel allowed calcium to flow into cells, triggering secondary signals that switched on an engineered calcium-sensitive gene that produces insulin. After 30 minutes of radio-wave exposure, the mice's insulin levels had increased and their blood sugar levels had dropped...
Even better, the researchers have already developed a way to achieve similar, albeit weaker, results without having to inject nanoparticles at all. They have developed cells that can grow their own required nanoparticles, meaning there would be no need to give patients strange chemicals or molecules.

$1.3B 'Brain in a Box' Project Faces Skepticism: Scientific American

$1.3B 'Brain in a Box' Project Faces Skepticism: Scientific American: At the heart of that approach is Markram's conviction that a good unifying model has to assimilate data from the bottom up. In his view, modelers should start at the most basic level--he focuses on ion channels because they determine when a neuron fires--and get everything working at one level before proceeding to the next. This requires a lot of educated guesses, but Markram argues that the admittedly huge gaps in knowledge about the brain can be filled with data as experiments are published--the Blue Brain model is updated once a week. The alternative approach, approximating and abstracting away the biological detail, leaves no way to be sure that the model's behavior has anything to do with how the brain works, said Markram.

This is where other computational neuroscientists gnash their teeth. Most of them are already using simple models of individual neurons to explore high-level functions such as pattern recognition. Markram's bottom-up approach risks missing the wood for the trees, many of them argued in Bern: the model could be so detailed that it is no easier to understand than the real brain. And that is if Markram can build it at all. Judging by what Blue Brain has accomplished in the past six years, critics said, that seems unlikely. The tiny swathe of simulated rat cortex has no inputs from sensory organs or outputs to other parts of the brain, and produces almost no interesting behavior, pointed out Kevan Martin, co-director of the INI, in an e-mail. It is "certainly not the case" that Markram has simulated the column as it works in a whole animal, he said.

Quantum dots control brain cells for the first time

Quantum dots control brain cells for the first time: First, they cultivated prostate cancer cells on a film covered with quantum dots. The cell membranes of the cancer cells were positioned next to the dots. The team then shone light onto the nanoparticles.

Energy from the light excites electrons within the quantum dot which causes the surrounding area to become negatively charged (see diagram). This caused some of the cancer cells' ion channels, which are mediated by a voltage, to open, allowing ions to rush in or out of the cells...

When Lin's team repeated their experiment with nerve cells, they found that stimulating the quantum dots caused ion channels to open and the nerve cell to fire.

Mimicking the brain, in silicon - MIT News Office

Mimicking the brain, in silicon - MIT News Office: With about 400 transistors, the silicon chip can simulate the activity of a single brain synapse...
The MIT researchers designed their computer chip so that the transistors could mimic the activity of different ion channels...

Previously, researchers had built circuits that could simulate the firing of an action potential, but not all of the circumstances that produce the potentials. “If you really want to mimic brain function realistically, you have to do more than just spiking. You have to capture the intracellular processes that are ion channel-based,” Poon says.

Mind controls: Good vibrations reach deep in the brain - health - 14 April 2011 - New Scientist

Mind controls: Good vibrations reach deep in the brain: The sound waves could be focused on an area of 1 to 3 cubic millimetres, similar to electrical deep brain stimulation. And the team targeted an area deep in the brain without affecting overlying tissue, by using several beams to converge on the right spot.

Neurons don't communicate using sound waves, so how does it work? Tyler's best guess is that the force of the sound waves knocks open the neurons' ion channels, which normally trigger electrical firing.

Math researcher illuminates cellular basis of neural impulse transmission

Math researcher illuminates cellular basis of neural impulse transmission: "The results of this work showed that the calcium current through an N-type channel was larger in comparison to calcium channels that are not involved in synaptic transmission, contrary to the currently accepted channel conductance hierarchy.
Furthermore, the authors' modeling work showed that the current through a single open N-type calcium channel may be sufficient to enable neurotransmitter release. These results demonstrate the degree to which N-type calcium channel properties are adapted for their role in synaptic transmission, and also shed light on the highly localized nature of intra-synaptic calcium signaling."

Tracking neuronal activity in the living brain

Tracking neuronal activity in the living brain: "YC-Nano accurately tracked the complex patterns of Ca2+ activation seen in the aggregating process of social amoeba Dictyostelium, revealing propagating waves throughout the aggregates in a rotating spiral. These indicators also performed well in monitoring neuronal activity in the brains of mice, and Mikoshiba foresees numerous experimental applications in the near future. “Since YC-Nano can be stably expressed in specific types of neurons for a long range of time,” he says, “we expect to perform chronic in vivo imaging and analyze the modifications of neuronal network activities underlying learning, development or diseases of the brain.”

Neurochip technology developed by Canadian team

Neurochip technology developed by Canadian team: "Previously it took years of training to learn how to record ion channel activity from brain cells, and it was only possible to monitor one or two cells simultaneously. Now, larger networks of cells can be placed on a chip and observed in minute detail, allowing the analysis of several brain cells networking and performing automatic, large-scale drug screening for various brain dysfunctions"

With Magnetic Nanoparticles, Scientists Remotely Control Neurons and Animal Behavior - UB NewsCenter

With Magnetic Nanoparticles, Scientists Remotely Control Neurons and Animal Behavior - UB NewsCenter: "The method the UB team developed involves heating nanoparticles in a cell membrane by exposing them to a radiofrequency magnetic field; the heat then results in stimulating the cell."