Scorpions Inspire Scientists in Making Tougher Surfaces for Machinery

Yellow fattail scorpion (Androctonus australis). 
(Credit: © Fyle / Fotolia)

Taking inspiration from the yellow fattail scorpion, which uses a bionic shield to protect itself against scratches from desert sandstorms, scientists have developed a new way to protect the moving parts of machinery from wear and tear.

A report on the research appears in ACS' journal Langmuir.

Zhiwu Han, Junqiu Zhang, Wen Li and colleagues explain that "solid particle erosion" is one of the important reasons for material damage or equipment failure. It causes millions of dollars of damage each year to helicopter rotors, rocket motor nozzles, turbine blades, pipes and other mechanical parts. The damage occurs when particles of dirt, grit and other hard material in the air, water or other fluids strike the surfaces of those parts. Filters can help remove the particles but must be replaced or cleaned, while harder, erosion-resistant materials cost more to develop and make. In an effort to develop better erosion-resistant surfaces, Han and Li's group sought the secrets of the yellow fattail scorpion for the first time. The scorpion evolved to survive the abrasive power of harsh sandstorms.

They studied the bumps and grooves on the scorpions' backs, scanning the creatures with a 3-D laser device and developing a computer program that modeled the flow of sand-laden air over the scorpions. The team used the model in computer simulations to develop actual patterned surfaces to test which patterns perform best. At the same time, the erosion tests were conducted in the simple erosion wind tunnel for groove surface bionic samples at various impact conditions. Their results showed that a series of small grooves at a 30-degree angle to the flowing gas or liquid give steel surfaces the best protection from erosion.

Story Source:

The above story is reprinted from materials provided byAmerican Chemical Society.

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Journal Reference:

1. Han Zhiwu, Zhang Junqiu, Ge Chao, Wen Li, Luquan Ren.Erosion Resistance of Bionic Functional Surfaces Inspired from Desert Scorpions. Langmuir, 2012; 120120101148000 DOI: 10.1021/la203942r

New technology could inspire brain implant for detecting and treating seizures

ScienceDaily (June 2, 2011) — Tiny electrodes have been coated with a drug-loaded polymer in an attempt to design an implant capable of detecting a number of neurological symptoms, such as those associated with an epileptic seizure, and treating them simultaneously.

In a study published June 2, 2011 in IOP Publishing's Journal of Neural Engineering, researchers have developed a novel technology to precisely modulate individual neurons in rats, allowing the molecular, neuronal, and circuit functions to be analysed with unprecedented precision.

Based on the electrical conducting properties of the polymer Polypyrrole (PPy), the researchers, from the University of Pittsburgh, have demonstrated a novel way of loading specific drugs onto an array of electrodes and triggering their release into cultured neurons, allowing for a more precise insight into the cellular mechanisms of neuronal networks.

On top of this, the researchers have also demonstrated how the release of drugs could be informed, in real-time, by the recording of activity in neurons, a step essential for creating a closed-loop system that both diagnoses and treats symptoms simultaneously, creating several potential applications.

Co-author Professor X Tracy Cui said, "We envision an implanted device in the future that will monitor the brain activity, detect or predict an onset of epileptic seizure, and send the command to the electrode at the most appropriate location, releasing an anti-convulsive drug to prevent the seizure."

Multielectrode arrays (MEAs) -- small devices that can control or record the electrical circuitry in neurons -- have long been used as a way of measuring neuronal activity and transforming this into an action; technologies such as ear implants and cardiac pacemakers have benefited from them.

Recent advances, however, have allowed MEAs to be coupled with devices that release specific drugs in order to test how neural circuits function, as well as investigating the underlying mechanisms within neuronal cells.

The researchers coated PPy, containing all of the necessary neurochemicals, onto an MEA. Whilst positioned on the cultured rat brain, the polymer was electrically stimulated, causing the neurochemicals to dissociate and diffuse away to the necessary locations.

Results showed that the drugs retained their activity and function with spatial and temporal precision.

Current state-of-the-art drug delivery methods, such as picospritzer and ionotopheriesis, give researchers a greater understanding of cellular mechanisms of neural dynamics; however, both of these techniques are limited to a few sites and face the risk of drug leakage.

By having the required neurochemicals dissociate from the polymer, this technique avoids the need for an external reservoir containing the drug, which would greatly increase the size of a potential implant and could cause tissue damage.

Professor Cui continues, "By directly loading a drug of interest onto an individual electrode site and using an electrical signal to trigger its release, we can precisely control the drug delivery site with ease. Additionally, our technology can be used for a combination of exogenous chemicals such as subtype-specific receptor antagonists, thus potentially allowing for more precise dissection of neural circuit function at the molecular level."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Institute of Physics, via EurekAlert!, a service of AAAS.

Journal References:

Stauffer et al. Rapid modulation of local neural activity by controlled drug release from polymer-coated recording microelectrodes. J. Neural Eng., 2011 [link]Stauffer et al. Rapid modulation of local neural activity by controlled drug release from polymer-coated recording microelectrodes. Journal of Neural Engineering, 2011; [link]

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