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Blog In New Science

Special magnetic coating used to kill bacteria, an antibiotic alternative

blog:17532:4::0
By Tim Sandle
Posted Jul 17, 2012 in Science
The problems and limitations of antibiotics and antimicrobial substances have received a great deal of attention in the press. The main concern is bacterial resistance. As an alternative, a science group have developed a special coating which can destroy bacteria on contact.
A research team based at the Nanyang Technological University (NTU), Singapore, have developed a special coating which has a magnetic-like feature. The magnetic nature is used to attract bacteria and then kills them. The application could lead to an antibiotic 'alternative'.
According to an NTU press release, the special sponge-like coating is made from Dimethyldecylammonium Chitosan methacrylate. The coating is a type of polymer which holds a positive charge. The charge acts like a type of magnet which generates a force. The force draws bacteria, which possess a negative charge on their cell walls, towards the surface. When the bacterium comes in contact with the coating, the cell walls are 'sucked' into the nanopores, causing the cell to rupture, thus killing the bacterium.
The Alpha Galileo Foundation notes that the coating has been tested against bacteria like Pseudomonas aeruginosa, which can cause infections in the upper respiratory tract, gastrointestinal tract and the urinary tract; and Staphylococcus aureus, which can cause infections ranging from skin boils or abscesses to deadly diseases such as pneumonia and meningitis.
The research was led by Professor Mary Chan, Acting Chair of NTU's School of Chemical and Biomedical Engineering. The research findings were published in the journal Nature Materials.
Chan is quoted by the Meridian Institute as saying, in relation to the research:
"The coating can also be applied on biomedical objects, such as catheters and implants to prevent bacterial infections, which is a serious cause of concern as many bacteria are now developing resistance to antibiotics - currently our main source of treatment for infections. By developing novel materials which uses physical interaction to kill bacteria cells, we envisage this can be an alternative form of treatment for bacterial infections in the near future."
A key advantage with the coating is that it is harmless to human cells.
The application is thus far being used by two companies: a contact lens manufacturer and a company specializing in animal care products. The next wave of developments is likely to be with implants and surgical instruments.
The journal [i]reference[/i] is:
Peng Li et al. A polycationic antimicrobial and biocompatible hydrogel with microbe membrane suctioning ability. Nature Materials, 2010; 10 (2): 149

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