Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ultrasound shown to be potentially safe, effective way to kill bacteria

16.12.2002


High-power ultrasound, currently used for cell disruption, particle size reduction, welding and vaporization, has been shown to be 99.99 percent effective in killing bacterial spores after only 30 seconds of non contact exposure in experiments conducted by researchers at Penn State and Ultran Labs, Boalsburg, Pa.



In the experiments, bacterial spores contained in a paper envelope, were placed slightly (3mm) above the active area of a specially equipped source of inaudible, high frequency (70 to 200 kHz) sound waves and hit for 30 seconds. There was no contact medium, such as water or gel, between the ultrasound source and the spores as is typically used in low power medical diagnostic ultrasound. The experiments mark the first time that Non Contact Ultrasound (NCU) has been shown to inactivate bacterial spores.

The researchers say the experiments demonstrate that NCU is a potentially safe, effective, non-radioactive way to decontaminate mail, including packages, since ultrasound waves potentially can penetrate cardboard and other wrappings just as they do layers of skin and tissue when used to image internal organs in the human body. They add that the technology could potentially sterilize medical and surgical equipment, food materials, the air duct systems of buildings, airplanes – even the space station.


The research team includes Dr. Kelli Hoover, assistant professor of entomology; Mahesh Bhardwaj, director of research and development, Ultran Labs; and Dr. Nancy Ostiguy, senior research associate in entomology. A patent, "Gas Contact Ultrasound Germicide and Therapeutic Treatment," is pending on the technique.

Hoover explains that the team used Bt spores in their experiments rather than the deadly anthrax spores found to contaminate mail last year. Bt, bacillus thuringiensis, is a common commercial insecticide and is also a close cousin of the anthrax bacillus. "Bacillus anthracis and bacillus thuringiensis are very close relatives," she adds. "They differ by only a few genes on their plasmids that encode different toxins. If you remove those plasmids, Bt cannot be distinguished from B. anthracis and therefore can serve as a safe model for testing."

In the experiments, samples of Bt spores were each subjected to different amounts of NCU exposure for different lengths of time. The spores were then supplied with nutrients so that they could grow. The number of bacterial spores that survived was determined by counting the number of colonies that grew.

The NCU devices used in the experiments were invented by Bhardwaj who also develops and markets speciality transducers for industrial and biomedical applications. Bhardwaj holds U.S and international patents for very high transduction NCU transducers that can generate high power ultrasound in air in the frequency range of 50 kHz to 10 MHz, comparable to conventional ultrasound frequencies.

"I thought these NCU transducers should be investigated to destroy germs and spores since conventional high power ultrasound was already being used for invasive and non-invasive tissue destruction," adds Bhardwaj, who is director of R&D at Ultran.

He says, "The efficiency of an NCU device is dependent on the properties of the transition layers on the piezoelectric material which create the high acoustic pressure ultrasound waves in air. This principal, in conjunction with new materials, is applied in the new patented NCU device developed for decomtamination."

Bhardwaj, who a Penn State alumnus, recruited Hoover and Ostiguy for the decontamination studies which were supported, in part, by Hoover’s Hatch grants.


The researchers described their findings in a paper, Destruction of Bacterial Spores by Phenomenally High Efficiency Non-Contact Ultrasonic Transducers," which is posted at http://link.springer.de/link/service/journals/10019/tocs.htm by the publication Materials Research Innovations and will be brought out in hard copy. To access the paper online, click on "OnLine First – Immediate Online Publications."

Barbara Hale | EurekAlert!
Further information:
http://www.psu.edu/
http://link.springer.de/link/service/journals/10019/tocs.htm

More articles from Process Engineering:

nachricht Harder 3D-printed tools – Researchers from Dresden introduce new process for hardmetal industry
11.10.2018 | Fraunhofer-Institut für Keramische Technologien und Systeme IKTS

nachricht Flying High with VCSEL Heating
04.10.2018 | Fraunhofer-Institut für Lasertechnik ILT

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

Im Focus: Nanorobots propel through the eye

Scientists developed specially coated nanometer-sized vehicles that can be actively moved through dense tissue like the vitreous of the eye. So far, the transport of nano-vehicles has only been demonstrated in model systems or biological fluids, but not in real tissue. The work was published in the journal Science Advances and constitutes one step further towards nanorobots becoming minimally-invasive tools for precisely delivering medicine to where it is needed.

Researchers of the “Micro, Nano and Molecular Systems” Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, together with an international...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Atomic parity violation research reaches new milestone

12.11.2018 | Physics and Astronomy

Nano-scale process may speed arrival of cheaper hi-tech products

09.11.2018 | Power and Electrical Engineering

How to produce fluorescent nanoparticles for medical applications in a nuclear reactor

09.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>