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StarStream: changing the way we use ultrasonic cleaning
Heralded as one of the most important developments in ultrasonic cleaning in decades, a new piece of technology that uses only cold water and ultrasonic bubbles has the potential to revolutionise cleaning in the healthcare industry and beyond.
The technology, known as StarStream, works by enhancing the cleaning power of a stream of water.
Currently prototyped as a hand-held, portable device, StarStream generates a stream of cold water at 2.1 litres/min from a 10mm diameter circular nozzle, down through which an ultrasonic field is projected. The device creates bubble clouds that clean to a very high level, surfaces with which they come into contact - without any need for detergents or chemicals.
This technology could provide a new low-cost, eco-friendly cleaning alternative for healthcare providers.
Developed by the University of Southampton, the technology has been exclusively licensed by Ultrawave, which has already manufactured over 50,000 pieces ultrasonic cleaning equipment; including systems to the NHS and other healthcare providers. Ultrawave is in the process of commercialising the product and StarStream prototypes are now being trialled by experts across the world, including high profile brand names in America and Germany and in the medical devices and healthcare industry in the UK.
Invented and patented by Professor Tim Leighton and Dr Peter Birkin, the technology works by propagating ultrasound energy (sound waves) through a low pressure flow of cold water. The effect causes ripples in the walls of microscopic bubbles in the water, which make the bubbles appear to 'shimmer', and generates high shearing forces in the liquid close to the bubbles' wall. This shear causes the bubbles to become abrasive, scouring against the surfaces they encounter and cleaning them to a very high standard.
These ultrasonic bubbles are especially effective at getting into hard-to-reach cracks and crevices to completely remove soil and bacteria. Recent independent tests found that StarStream is 1,000 times more effective than water alone in decontaminating the microorganism Pseudomonas aeruginosa, a major cause of hospital acquired infections.
For the healthcare sector, StarStream's innovative technology has the potential to significantly speed-up and improve the current three-stage decontamination process of gross soil removal, disinfection and sterilisation.
As StarStream applies a direct stream of water onto the item, it removes any danger of 'drag-through' contamination during the first stage of gross soil removal. This can happen when dipping an item into a bath or tank and then lifting it back out through contaminated liquid. Using StarStream, the item is cleaned and rinsed simultaneously and - importantly - uniformly across the entire area.
StarStream not only offers a superior clean in stage one; it also destroys bacteria. This gives it the potential to combine the first two stages of the current decontamination process - the removal of gross soil and the disinfection stage. This second stage usually involves high temperatures, chemicals and detergents to reach a satisfactory log reduction rate, but - using only cold water and ultrasonic energy - StarStream is said to be already achieving a 3-log reduction - a 99.9% kill rate in potentially harmful micro-organisms. Further tests are in the pipeline using a biocide with the water, which will see its log reduction rating increase dramatically. This could allow StarStream to conveniently cover both stages.
"There are many studies and trials ongoing, which are delivering exciting results, and 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," reveals John Melville, managing director of Ultrawave. "It's a very exciting piece of technology. The cleaning industry hasn't seen a development like this in many, many years.
"In the NHS, there is a real opportunity to revolutionise the decontamination process using StarStream technology. It will significantly reduce the resources used, including disinfectants, electricity and water, which will save costs and the environment. It will also cut back on the time the decontamination process takes, whilst reducing opportunities for human error by removing the number of stages an item has to go through before it reaches a 100% kill rate."
Studies show that StarStream's ability to clean using only cold water also leads to significant reductions in power bills. It can produce up 97% energy savings compared to current commercial products, which is appealing to industries looking to reduce costs and improve their environmental impact, such as healthcare.
StarStream also works without having to add detergent to the water, which minimises the risk of run-off polluting groundwater and streams, and simplifies the task of turning the used water back into safe drinking water.
StarStream is also portable, opening up a range of new opportunities for items that cannot currently be cleaned using ultrasonic cleaning tanks or baths because they themselves are not portable.
Inventor Professor Leighton says: "We believe that it is very important to undertake fundamental multidisciplinary science and engineering because that produces step-change, as opposed to incremental, progress. But it is equally vital that those breakthroughs do not stay between the pages of an academic journal, but get out into the wider world to do the basic job of helping people and saving lives.
"We are entering a new era when the importance of cleaning will once again be re-emphasised. Periodically in history, pioneers, such as Aulus Cornelius Celsus in Rome 2000 years ago, Ignaz Semmelweis and Florence Nightingale in the 19th century, have changed healthcare and saved lives by emphasising the need for cleanliness. But in the last 50 years, the ready availability of antibiotics and other antimicrobials has perhaps made us complacent, allowing the alarming increase in resistant microbe strains.
"By 2050 drug resistant diseases could be killing more people than cancer - an extra 10 million deaths per year. They would also cause a loss to the global output of 100 trillion dollars - that is equivalent to a sum greater than the current global economy."
"Cleaning is vital. If we can stop the microbe entering the body, we will not have an infection to fight. If we can stop it entering the wider world, we remove the ability for strains to travel between hosts and develop resistance."
Early application studies of StarStream's potential started at the University of Southampton in 2010. A huge range of applications and samples were tested with success including blood, human tissue, soot, toothpaste, soil, peanut butter, vegetables, cloth, oil, make-up, Vaseline and skin.
The technology is currently being tested by NAMRIP, the Network for Anti-Microbial Resistance & Infection Prevention, which was founded by Professor Leighton in 2015 and already has attracted over £1 million investment from the Engineering & Physical Sciences Research Council, and the Medical Research Council.
In NAMRIP, engineers, physical scientists, clinicians and social scientists are working together to integrate responses to the technology in the fields of dentistry and surgical instrument cleaning, as well as others. It 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 CJD. It has also been tested for dental bacteria removal and hand-washing in healthcare.
Recent research by Dr Leighton and the University of Southampton into the removal of dental biofilms with an ultrasonically activated water stream illustrated the power of StarStream. 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%) in biomass and 0.17 log reduction (33.8%) in thickness in S. mutans biofilm. The StarStream caused a further 2.3 log reduction in biomass (99.5% reduction compared with untreated water) and a 2.9 log reduction in thickness - a 99.9% reduction in comparison. Similar results were made for A. naeslundii biofilms and S. oralis biofilm.
The initial research into disruptive technologies was led by Professor Leighton - an internationally recognised acoustician who is known worldwide for his ground-breaking research in acoustics in liquids - and Dr Peter Birkin, a Senior Lecturer in Electrochemistry at the University of Southampton.
Along with their former students Doug Offin and Chris Vian, and using funding from the Defence Science & Technology Laboratory, their sustained effort to understand the fundamental processes that underpin ultrasonic technology led to their discovery of StarStream's unique technology in 2010.
The potential of StarStream was spotted early on. In 2011, it won the Royal Society's Brian Mercer Award for Innovation. This provided the team at the University of Southampton with a new platform for the technology and additional £250,000 in funding to look into further applications.
The team then approached Ultrawave, which has been designing and manufacturing ultrasonic cleaning systems for 25 years, for a collaboration to help bring the technology to market. Ultrawave has the exclusive licence for StarStream and is working to commercialise it in continual partnership with Professor Leighton and the University of Southampton.
In 2012, StarStream collected the Institute of Chemical Engineering Award for Water Management & Supply for its potential to generate significant savings in water use in a range of cleaning applications, beating off competition from the likes of GlaxoSmithKline and Scottish Water. In 2014, it won an international accolade - and recognition - when it was named Best New Product of the Year from S-lab (Safe, Successful and Sustainable Laboratories).
Further studies are needed to fully comprehend the scope and impact of this new technology, but with comprehensive feedback and study results already coming in from across the globe - and more planned - it is clear that this technology will change the future of the industry and provide the healthcare industry, and many others, with vastly improved cleaning and decontamination options in the future.
19th November 2015