Ground-Breaking Research: Sterilising With Ionized Plasmas

Medical News Today has published a news item on research being undertaken at University of California, Berkeley, on the use of ionized plasmas to sterilise objects, liquids and even tissue surfaces.  This ground-breaking work might have massive implications for the Medical Device industry across the world and as such we thought medlatest readers would be interested. The article can be found here, but highlights follow:

“The field of low-temperature plasmas is booming, and this is not just hype. It’s real!” 


Research scientist and chemical engineer David Graves, the Lam Research Distinguished Professor in Semiconductor Processing at UC Berkeley has shown that ionized plasmas like those in neon lights and plasma TVs not only can sterilize water, but make it antimicrobial for as long as a week after treatment.


Plasma discharges have been used since the late 1800s to generate ozone for water purification, and some hospitals use low-pressure plasmas to generate hydrogen peroxide to decontaminate surgical instruments. Many surgeons will be familiar with plasma technology, RF ablation devices being effectively plasma generators which remove tissue or coagulate blood. Only recently, however, have low-temperature plasmas been used as described in this work to potentially disinfect objects, liquids and even tissue surfaces. Mutant strains of E. coli have caused outbreaks of intestinal upset and even death when they have contaminated meat, cheese and vegetables, so the potential to cheaply kill them or render materials resistant to them is appealing especially in less well resourced situations.

How it Works

Plasmas generated by brief sparks in air next to a container of water turned the water about as acidic as vinegar and created a cocktail of highly reactive, ionized molecules  identified as hydrogen peroxide and various nitrates and nitrites, all well-known antimicrobials. Nitrates and nitrites have been used for millennia to cure meat, for example.

Water treated with plasma killed essentially all the E. coli bacteria dumped in within a few hours of treatment and still killed 99.9 percent of bacteria added after it sat for seven days.

“I’m a chemical engineer who applies physics and chemistry to understanding plasmas”

Advantages Compared with Current Techniques

Devices able to produce such plasmas are cheap, which means they could be life-savers in developing countries, disaster areas or on the battlefield where sterile water for medical use – whether delivering babies or major surgery – is in short supply and expensive to produce. “One of the most difficult problems associated with medical facilities in low-resource countries is infection control,” added Graves. “It is estimated that infections in these countries are a factor of three-to-five times more widespread than in the developed world.”

Potential Applications

  • Sterilising instruments, aiding wound healing: “We know plasmas will kill bacteria in water, but there are so many other possible applications, such as sterilizing medical instruments or enhancing wound healing,” said Graves.
  • Developing Countries and disaster zones: Low-temperature plasmas as disinfectants are “an extraordinary innovation with tremendous potential to improve health treatments in developing and disaster-stricken regions,” said Phillip Denny, chief administrative officer of UC Berkeley’s Blum Center for Developing Economies, which helped fund Graves’ research and has a mission of addressing the needs of the poor worldwide.
  • Killing prions: Based on other experiments, Graves and colleagues at the University of Maryland in College Park reported at the annual meeting of the American Vacuum Society that plasma can also “kill” dangerous proteins and lipids – including prions, the infectious agents that cause mad cow disease – that standard sterilization processes leave behind.

When will we see the Technology in Action 

It sounds rather like a commercial application is not on the short term horizon, requiring further research.

Graves said; “Despite the widespread use of plasmas they are still not well characterized. Plasma created in air, for example, produces different molecules than plasma in helium or argon. Much needs to be learned about different ways of producing plasmas, including plasma needles and jets, and how to maximize exposure against skin or liquid, such as by confining the plasma-generated chemicals near the surface of the treated object.”

At medlatest we’re excited and intrigued by the technology and will be following the work with great interest.

Source: Medical News Today, medlatest staff