The
superbugs have met their match.
Conceived
at Nanyang Technological University (NTU), it comes in the form of a coating
which has a magnetic-like feature that attracts bacteria and kills them without
the need for antibiotics.
The
killer coating, which has shown to destroy 99% of the bacteria and fungi that
it comes in contact with, is now being used by two companies: a contact lens
manufacturer and a company specializing in animal care products.
The
next step is to extend its use in a wide range of biomedical and consumer
products, ranging from implants and surgical instruments to kitchen utensils
and cutlery, as it is harmless to human cells.
This
is an alternative solution which could replace antibiotics—currently the main defense
against bacteria—now powerless against superbugs.
The
brainchild of Professor Mary Chan, Acting Chair of NTU’s School of Chemical and
Biomedical Engineering, the coating made from Dimethyldecylammonium Chitosan, methacrylate, has earned a
place in Nature Materials.
This “sponge-like” polymer holds a positive charge, which acts as a magnet type of
force to draw in bacteria which has a negative charge on their cell walls. 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
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,” Chan said.
“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.”
Superbugs
which had fallen prey to the coating include 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.
This
research for a broad-spectrum antimicrobial coating was first sparked off by Chan
wanting to find an effective way to combat bacteria and fungi on contact lenses
which could cause corneal infections (microbial keratitis) that could lead to
permanent visual damage.
According
to a 2006 study, the estimated annual incidence of a common fungi corneal
infection, Fusarium
keratitis, related to contact lens wear in Singapore is 2.35 per 10,000
wearers.
Building
on the success of the antibacterial coating, Chan and her doctoral student, Li
Peng, have now succeeded in making another broad-spectrum antimicrobial
solution of a similar kind which is highly selective, killing off only bacteria
and fungi without harming human cells in
vitro.
Their
research was published in Advanced
Materials. This liquid material based on cationic antimicrobial peptidopolysaccharide,
is a polymer which is attracted to microbial cell walls. When the two come into
contact, the integrity of the cell wall is disrupted which leads to its rupture
and death.
As
this novel material kills cells via the destruction of cell walls, it makes it
extremely difficult for bacteria to develop an effective resistance.
Chan
hopes to further develop this solution into topical applications such as cream
and lotions, which can be used to disinfect and treat serious or chronic wounds
such as lesions suffered by diabetic patients, killing any bacteria present
that are resistant to antibiotics.
“Our
long term goal is to develop this into an ingestible form, so it can
effectively treat bacterial infections within the body, such as pneumonia and
meningitis, replacing antibiotics as the standard treatment.” she added.
The
two antimicrobial prototypes—the coating and the liquid solution—took a total
of five years to research and costs over $800,000 to develop.
Chan
now aims to improve the liquid solution by developing it into a safe and proven
antibiotic replacement within the next five years as the demand for such
alternatives will be even higher with the rapid emergence of superbugs.
Nanyang Technological University
Filed Under: Drug Discovery