Are ultrasonic bubbles the new landscape of medical decontamination?
Have we entered a new era of medical and industrial cleaning?
(Photo courtesy of Ultrawave.)
The creators of a handheld device that cleans surfaces using only low-pressure cold water and ultrasonic bubbles certainly seem to think so.
Developed by researchers at the University of Southampton, the portable device called StarStream generates a cold water stream flowing at a rate of 2.1 L/minute from a 10mm diameter circular nozzle.
The device also sends an ultrasonic signal through the water stream. Propagating the ultrasound energy through a low pressure flow of water causes ripples in the walls of microscopic bubbles in the water.
This makes the bubbles appear to “shimmer” and generates high shearing forces in the liquid close to the bubbles’ wall. These shear forces render the bubbles abrasive, causing them to act as a scouring agent against surfaces they come into contact with.
The ultrasonic bubbles are able to get into small cracks and crevices to remove soil and bacteria, decontaminating surfaces.
As the device cleans without the need for detergents or chemicals, the creators see widespread applications in the medical and industrial manufacturing fields. They also predict significant energy savings: up to 97 percent compared to current commercial products, due to requiring only cold water to operate.
For healthcare sector uses, the StarStream technology may potentially speed up the current three-stage decontamination process of gross soil removal, disinfection and sterilization.
As the device cleans by applying a constant stream of water directly against the surface, there is a reduced danger of “drag-through’ contamination during the first stage of gross soil removal.
This is a common concern when using dip bath or tank decontamination methods, as when lifting the items back out they will pass through contaminated liquid.
StarStream combines the first two steps of the decontamination process by cleaning and rinsing simultaneously and uniformly across the entire surface of the object and any small cracks within.
This second stage usually involves high temperatures, chemicals and detergents to reach a satisfactory log reduction rate.
But according to the creators, even using only cold water and ultrasonic energy, the StarStream device is already achieving a 3-Log Reduction; a 99.9 percent kill rate in potentially harmful micro-organisms.
As StarStream cleans without antibiotics it can help to reduce the use of these chemicals. This can help to prevent the rise of anti-biotic resistant bacteria.
However, further tests are planned using a biocide with the water, which is expected to increase the Log Reduction rating. However, depending on the choice of biocide, the risk of exacerbating anti-biotic resistant bacteria problems might increase.
Recent Research with NAMRIP
Recent research by StarStream’s inventor Tim Leighton and the University of Southampton into the removal of dental biofilms with an ultrasonically activated water stream illustrated the capabilities of the device.
Results showed that StarStream was significantly more effective at removing biofilms grown on a surface than a water stream alone.
Water alone caused a 0.10 log reduction (20.7 percent) in biomass and 0.17 log reduction (33.8 percent) in thickness in S. mutans biofilm. The StarStream caused a further 2.3 log reduction in biomass (99.5 percent reduction compared with untreated water) and a 2.9 log reduction in thickness – a 99.9 percent reduction in comparison. Similar results were discovered when cleaning A. naeslundii biofilms and S. oralis biofilm.
The technology is also undergoing testing by NAMRIP (Network for Anti-Microbial Resistance and Infection Prevention), which was founded by Professor Leighton in 2015.
At NAMRIP, engineers, physical scientists, clinicians and social scientists are working together to integrate responses to the technology in the fields of dentistry, surgical instrument cleaning and handwashing in the medical industry, among others.
StarStream has already been successfully tested in joint replacements, cleaning bones before transplant and in cleaning surgical instruments for brain tissue decontamination, which is especially important in tackling Creutzfeldt-Jakob disease (CJD).
The device is currently in prototype testing stages and is intended for commercialization for the medical industry and others, for the cleaning and sterilization of manufactured parts or products.
“There are many studies and trials on-going, which are delivering exciting results,” stated John Melville, managing director of Ultrawave, the company licensing the technology.
“We want to partner with more businesses and organisations in the healthcare industry and beyond to test it further and help us explore its full potential. It’s a very exciting piece of technology. The cleaning industry hasn’t seen a development like this in many, many years,” Melville continued.
For more on the StarStream, check out their website.
