Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Flexible, Printable Sensors Detect Underwater Hazards

11.07.2011
Breakthroughs in nanoengineering often involve building new materials or tiny circuits. But a professor at the University of California, San Diego is proving that he can make materials and circuits so flexible that they can be pulled, pushed and contorted – even under water – and still keep functioning properly.

Joseph Wang has successfully printed thick-film electrochemical sensors directly on flexible wetsuit material, paving the way for nano devices to detect underwater explosives or ocean contamination.

“We have a long-term interest in on-body electrochemical monitoring for medical and security applications,” said Wang, a professor in the Department of NanoEngineering in UC San Diego’s Jacobs School of Engineering. “In the past three years we’ve been working on flexible, printable sensors, and the capabilities of our group made it possible to extend these systems for use underwater.”

Wang notes that some members of his team – including electrical-engineering graduate student Joshua Windmiller – are surfers. Given the group’s continued funding from the U.S. Navy, and its location in La Jolla, it was a logical leap to see if it would be possible to print sensors on neoprene, the synthetic-rubber fabric typically used in wetsuits for divers and surfers.

The result: development of “wearable electrochemical sensors for in situ analysis in marine environments.” The paper, published last month in the journal Analyst*, was co-authored by UCSD’s Wang, Windmiller and visiting scholar Gabriela Valdés-Ramírez from Mexico, as well as Michael J. Schöning and Kerstin Malzahn from the Institute of Nano- and Biotechnologies of Germany’s Aachen University of Applied Sciences. (Malzahn is currently a visiting graduate student at UCSD from the German university.)

UCSD has a full U.S. patent pending on the technology, and has begun talks on licensing the system to a Fortune 500 company.

Wang’s 20-person research group is a world leader in the field of printable sensors. But to prove that the sensors printed on neoprene could take a beating and continue working, some of Wang’s colleagues took to the water.

“Anyone trying to take chemical readings under the water will typically have to carry a portable analyzer if they want to detect pollutants,” said Wang, whose group is based in the California Institute for Telecommunications and Information Technology (Calit2) at UCSD. “Instead, we printed a three-electrode sensor directly on the arm of the wetsuit, and inside the neoprene we embedded a 3-volt battery and electronics.”

The electrochemical sensors are based on applying voltage to drive a reduction-oxidation (redox) reaction in a target threat or contaminant – which loses or gains electrons – then measuring the current output. The wearable microsystem provides a visual indication and alert if the levels of harmful contaminants or explosives exceed a pre-defined threshold. It does so by mixing different enzymes into the carbon ink layer before printing on the fabric. (For example, if the enzyme tyrosinase interacts with the pollutant phenol, the LED light switches from green to red.)

The electronics are packed into a device known as a potentiostat that is barely 19mm by 19mm. (The battery is stored on the reverse side of the circuit board.)

In the experiments described in the Analyst article, Wang and his team tested sensors for three potential hazards: a toxic metal (copper); a common industrial pollutant, phenol; and an explosive (TNT). The device also has the potential to detect multiple hazards. “In the paper we used only one electrode,” noted Wang, “but you can have an array of electrodes, each with its own reagent to detect simultaneously multiple contaminants.”

The researchers believe that neoprene is a particularly good fabric on which to print sensors because it is elastic and repels water. It permits high-resolution printing with no apparent defects.

The UCSD team tested the sensor for explosives because of the security hazard highlighted by the 2000 attack on the USS Cole in Yemen. The Navy commonly checks for underwater explosives using a bulky device that a diver must carry underwater to scan the ship’s hull. Using the microsystem developed by Wang and his team, the sensor printed on a wetsuit can quickly and easily alert the diver to nearby explosives.

Wang’s lab has extensive experience printing sensors on flexible fabrics, most recently demonstrating that biosensors printed on the rubber waistband of underwear can be used continuously to monitor the vital signs of soldiers or athletes. The researchers were uncertain, however, about whether bending the printed sensors under water – and in seawater – would still let them continue functioning properly.

In the end, even underwater, and with bending and other deformations, the sensors continued to perform well. “We still need to validate and test it with the Navy,” said Wang. “While the primary security interest will be in the detection of explosives, the Navy in San Diego bay has also detected large concentrations of toxic metals from the paint on Navy ships, so in principle we should be able to print sensors that can detect metals and explosives simultaneously.”

Wang’s work in flexible sensors grew out of 20 years’ experience with innovations in glucose monitoring, ultimately in the form of flexible glucose strips that now account for a $10 billion market worldwide.

Work on the underwater sensors was supported by the Office of Naval Research.

* Wearable electrochemical sensors for in situ analysis in marine environments, Kerstin Malzahn, Joshua Ray Windmiller, Gabriela Valdés-Ramírez, Michael J. Schöning and Joseph Wang, Analyst, June 2011.

Doug Ramsey | Newswise Science News
Further information:
http://www.ucsd.edu

More articles from Power and Electrical Engineering:

nachricht Researchers measure near-perfect performance in low-cost semiconductors
18.03.2019 | Stanford University

nachricht Robot arms with the flexibility of an elephant’s trunk
18.03.2019 | Universität des Saarlandes

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

Im Focus: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

Im Focus: Sussex scientists one step closer to a clock that could replace GPS and Galileo

Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...

Im Focus: Sensing shakes

A new way to sense earthquakes could help improve early warning systems

Every year earthquakes worldwide claim hundreds or even thousands of lives. Forewarning allows people to head for safety and a matter of seconds could spell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Levitating objects with light

19.03.2019 | Physics and Astronomy

New technique for in-cell distance determination

19.03.2019 | Life Sciences

Stellar cartography

19.03.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>