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Comparative TEM images of microbes in the absence and
presence of polymer 3. MRSA (a), before (left) and after incubation (right) with polymer 3 for 8 h at lethal doses (10.8 mM for MRSA and 16.3 mM for E. faecalis and C. neoformans), values that are slightly above the MICs. After
treatment, cell walls and membranes were damaged, and cell death was observed. In C. neoformans, large empty spaces were observed in the cytosol,as well as a burst of the cytoplast. In each lettered part of the figure, the bottom two images are magnified with respect to the top images. Scale bars: 0.2 mm (top) and 100 nm (bottom) (a,b); 2 mm (top) and 0.5mm
(bottom) (c). Image: Nature Chemistry
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Researchers
from IBM and the Institute of Bioengineering and Nanotechnology have
discovered a nanomedicine breakthrough in which new types of polymers
were shown to physically detect and destroy antibiotic-resistant
bacteria and infectious diseases like Methicillin-resistant
Staphylococcus aureus, known as MRSA.
Discovered
by applying principles used in semiconductor manufacturing, these
nanostructures are physically attracted to infected cells like a magnet,
allowing them to selectively eradicate difficult to treat bacteria
without destroying healthy cells around them. These agents also prevent
the bacteria from developing drug resistance by actually breaking
through the bacterial cell wall and membrane, a fundamentally different
mode of attack compared to traditional antibiotics.
MRSA
is just one type of dangerous bacteria that is commonly found on the
skin and easily contracted in places like gyms, schools and hospitals
where people are in close contact. In 2005, MRSA was responsible for
nearly 95,000 serious infections, and associated with almost 19,000
hospital stay-related deaths in the United States.
The
challenge with infections like MRSA is two fold. First, drug resistance
occurs because microorganisms are able to evolve to effectively resist
antibiotics because current treatments leave their cell wall and
membrane largely undamaged. Additionally, the high doses of antibiotics
needed to kill such an infection indiscriminately destroy healthy red
blood cells in addition to contaminated ones.
“The
number of bacteria in the palm of a hand outnumbers the entire human
population,” says Dr. James Hedrick, advanced organic materials
scientist, IBM Research – Almaden. “With this discovery we’ve been able
to leverage decades of materials development traditionally used for
semiconductor technologies to create an entirely new drug delivery
mechanism that could make them more specific and effective.”
If
commercially manufactured, these biodegradable nanostructures could be
injected directly into the body or applied topically to the skin,
treating skin infections through consumer products like deodorant, soap,
hand sanitizer, table wipes and preservatives, as well as be used to
help heal wounds, tuberculosis and lung infections.
“Using
our novel nanostructures, we can offer a viable therapeutic solution
for the treatment of MRSA and other infectious diseases. This exciting
discovery effectively integrates our capabilities in biomedical sciences
and materials research to address key issues in conventional drug
delivery,” says Dr. Yiyan Yang, group leader, Institute of
Bioengineering and Nanotechnology, Singapore.
How it works
click to enlarge
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The
human body’s immune system is designed to protect us from harmful
substances, both inside and out, but for a variety of reasons, many of
today’s conventional antibiotics are either rejected by the body or have
a limited success rate in treating drug-resistant bacteria. The
antimicrobial agents developed by IBM Research and the Institute of
Bioengineering and Nanotechnology are specifically designed to target an
infected area to allow for a systemic delivery of the drug.
Once
these polymers come into contact with water in or on the body, they
self assemble into a new polymer structure that is designed to target
bacteria membranes based on electrostatic interaction and break through
their cell membranes and walls. The physical nature of this action
prevents bacteria from developing resistance to these nanoparticles.
The
electric charge naturally found in cells is important because the new
polymer structures are attracted only to the infected areas while
preserving the healthy red blood cells the body needs to transport
oxygen throughout the body and combat bacteria.
Unlike
most antimicrobial materials, these are biodegradable, which enhances
their potential application because they are naturally eliminated from
the body (rather than remaining behind and accumulating in organs).
The
antimicrobial polymers created by IBM Research and the Institute of
Bioengineering and Nanotechnology and were tested against clinical
microbial samples by the State Key Laboratory for Diagnosis and
Treatment of Infectious Diseases, First Affiliated Hospital, College of
Medicine and Zhejiang University in China.
The full research paper was recently published in the peer-reviewed journal Nature Chemistry.
Researchers from IBM are already applying principles from nanotechnology to create potential medical innovations like the DNA Transistor and 3-D MRI.
Most recently they have been working on a one step
point-of-care-diagnostic test based on an innovative silicon chip that
requires less sample volume, can be significantly faster, portable, easy
to use, and can test for many diseases. Dubbed “Lab on a Chip,”
the results are so quick and accurate that a small sample of a
patient’s blood could be tested immediately following a heart attack to
enable the doctor to quickly take a course of action to help the patient
survive.
Original article
