Antibacterial stainless steel created

Materials scientists at the University of Birmingham have devised a way of making stainless steel surfaces resistant to bacteria in a project funded by the Engineering and Physical Sciences Research Council which culminated this week.

By introducing silver or copper into the steel surface (rather than coating it on to the surface), the researchers have developed a technique that not only kills bacteria but is very hard and resistant to wear and tear during cleaning. 

Bacteria resistant surfaces could be used in hospitals to prevent the spread of superbug infections on stainless steels surfaces, as well as in medical equipment, for example, instruments and implants.  They would also be of use to the food industry and in domestic kitchens. 

The team has developed a novel surface alloying technology using Active Screen Plasma (ASP) with a purpose designed composite or hybrid metal screen.  The combined sputtering, back-deposition and diffusion allows the introduction of silver into a stainless steel surface, along with nitrogen and carbon.  The silver acts as the bacteria killing agent and the nitrogen and carbon make the stainless steel much harder and durable. 

The researchers replicated the cleaning process for medical instruments in hospitals.  After cleaning the treated instruments 120 times they found that the antibacterial properties of the stainless steel were still intact and the surface still resistant to wear. 

Hanshan Dong, Professor of Surface Engineering at the University of Birmingham and lead investigator, said: ‘Previous attempts to make stainless steel resistant to bacteria have not been successful as these have involved coatings which are too soft and not hard-wearing.  Thin antibacterial coatings can be easily worn down when interacting with other surfaces, which leads to a low durability of the antibacterial surface.  Our technique means that we avoid coating the surface, instead we modify the top layers of the surface.’

Professor Dong’s team are confident that this technique could be used in the manufacturing of stainless steel products as they are already able to surface engineer items of up to two metres x two metres in the laboratory.

Provided by University of Birmingham

Australian honey proves to be a powerful anti-bacterial treatment

Honey sourced from an Australian native myrtle tree has been found to have the most powerful anti-bacterial properties of any honey in the world and could be used to treat antibiotic-resistant bacterial infections that commonly occur in hospitals and nursing homes.

A Brisbane-based research group found that Australian native myrtle honey has very high levels of the anti-bacterial compound, Methylglyoxal (MGO), and outperforms all medicinal honeys currently available on the market, including Manuka honeys.

Led by the Queensland Alliance for Agriculture and Food Innovation (QAAFI), which is a partnership between The University of Queensland and the Queensland Government's Department of Employment, Economic Development and Innovation (DEEDI), the research is being carried out in conjunction with The Australian Organic Honey Company & Medi Bioactive Australia.

The project to date has involved comprehensive trials with honey harvested from a native species of myrtle (leptospermum polygalifolium), which is distributed along the Australian eastern seaboard from the south coast of NSW to Cape York.

CEO of The Australian Organic Honey Company & Medi Bioactive Australia, Carolyn MacGill, said the findings had shown anti-bacterial potency levels that could allow for the development of highly effective anti-bacterial treatments.

“We have had MGO readings in excess of 1750 mg/kg in certain batches of honey. This would make this range of honeys one of the most potent in the world,” Ms MacGill said.

Honeys investigated by the research group were effective as anti-bacterial treatments when used in the range of 500 – 1750 mg/kg MGO to prevent the growth of Methicillin-Resistant staphylococcus aureus (MRSA), a common bacterial infection in hospitals and community facilities where residents are immune challenged, such as nursing homes.

Chief researcher working on the project, QAAFI scientist Dr Yasmina Sultanbawa, said the potency of the honeys meant that only a small amount was required to fight infection.

“The sheer strength, due to high levels of active compounds in these honeys, has meant that we have been able to completely inhibit MRSA for example in in-vitro studies with a relatively small quantity of the honey,” Dr Sultanbawa said.

“This means potential products could maintain significant levels of anti-bacterial activity even in surface wounds where the honey is diluted in the bed of the infection.

“The presence of MRSA in a wound is a matter of concern and MRSA-colonised wounds are an increasingly urgent problem in hospitals and nursing homes. The continued emergence of strains with resistance to antibiotics or even antiseptics adds to the difficulties of treating these infections.

“Investigations into unconventional remedies that are non-toxic and unlikely to result in resistance to the treatment, such as the QAAFI research into bioactive honeys, is very promising.”

According to Ms MacGill, the potential of the honeys could ultimately result in a range of highly sought-after products.

“Our research to date has produced overwhelming results in the quest to inhibit the very common infection MRSA at very low percentage rates of application,” Ms MacGill said.

“This could provide enormous benefits for Australian and international medical fraternities and their patients.”

Provided by University of Queensland (news : web)