Researchers from the University of Southampton, working with colleagues at
the Defence Science and Technology Laboratory (Dstl), have developed a new
technology based on nanoparticles to kill dangerous bacteria that hide
inside human cells.
Burkholderia is a genus of bacterium that causes a deadly disease called
melioidosis. This disease kills tens of thousands of people each year,
particularly in southeast Asia. Antibiotics administered orally or
intravenously often don’t work very well against it as the bacteria hide
away and grow in white blood cells called macrophages.
New research, led by Dr. Nick Evans and Dr. Tracey Newman, has shown that
tiny capsules called polymersomes – which are about 1000th the diameter of a
human hair – could be used to carry bug-killing antibiotics right to the
site where the bacteria grow inside the cells. Their findings have been
published in the journal ACS Nano.
Macrophages are cells of the immune system that have evolved to take up
particles from the blood which is crucial to their role in preventing
infection, but it also means that they can be exploited by some bacteria
which infect and grow inside them.
In this study, the research team added polymersomes to macrophages that were
infected with bacteria. Their results showed that the polymersomes were
readily taken up by the macrophages and associated with the bacteria inside
the cells. This means they could be an effective way to get a high
concentration of antibiotics to the site of infection. The team hope this
could eventually lead to patients being treated by injection or inhalation
of antibiotic-laden capsules, saving many lives each year.
Eleanor Porges, a PhD student in the University of Southampton’s Faculty of
Medicine and first author on the study said: “What is so attractive about
this technology is that the antibiotics are only released when they get to
the place they are needed. We hope by doing this we may be able to use less
antibiotic and to even repurpose antibiotics that wouldn’t normally be
considered effective.”
Dr. Nick Evans, Associate Professor in Bioengineering at the University of
Southampton added: “What was interesting is that previous research has
involved complicated chemistry to engineer the polymersomes in order to
release the drug at the right time and place by changes to heat or the pH
scale. Our research has shown that this is not necessary, which makes their
use much less complex and perhaps easier to produce for clinical use.
“The results of our study were a real team effort, with people all pulling
together from backgrounds in microbiology, imaging and nanotechnology
working between Dstl and Southampton. This is what made the data so
compelling.”
The team are now in the early stages of developing this for clinical
application with Dstl, the science inside UK defense and security.
Reference:
Antibiotic-Loaded Polymersomes for Clearance of Intracellular Burkholderia
thailandensis by Eleanor Porges, Dominic Jenner, Adam W. Taylor, James S. P.
Harrison, Antonio De Grazia, Alethia R. Hailes, Kimberley M. Wright, Adam O.
Whelan, Isobel H. Norville, Joann L. Prior, Sumeet Mahajan, Caroline A.
Rowland, Tracey A. Newman and Nicholas D. Evans, 5 November 2021, ACS Nano.