Saturday , September 26 2020

New nanoparticle weapons to combat deadly fungi


Candida albicans

  • Researchers at Monash University got insights into how nanoparticles can develop a biosensor to prevent deadly diseases from medical devices, such as catheters.
  • Candida albicans it can become a serious problem for people who are seriously ill or immunized.

Researchers at Monash University have explored how nanoparticles can be used to identify the presence of invasive and sometimes deadly microbes and to deliver targeted treatments more effectively.

The study was conducted as an interdisciplinary collaboration between microbiologists, immunologists and engineers led by Dr. Simon Corey of the Department of Chemical Engineering at Monash University and Professor Anna Traven of the Monash Institute of Biomedical Discoveries (BDI). It was recently published in the journal American Chemical Society ACS Applied Interfaces and Material.

Candida albicans, the most commonly discovered germ, can become deadly when colonized on devices such as catheters embedded in the human body. Although usually found in healthy people, this germ can become a serious problem for those who are severely ill or immune-deficient.

The germ forms a biofilm when colonized using, for example, a catheter as a source of infection. It then spreads to the bloodstream to infect the internal organs.

"The mortality rate in some patient populations can be as high as 30 to 40 percent even if you treat people. When colonized, it is highly resistant to anti-fungal treatments, "Professor Traven said.

"The idea is that if you can diagnose this infection early, then you may have a much greater chance of successfully treating it with current anti-fungal drugs and stop having a fully developed systemic infection, but our current diagnostic methods are lacking. A biosensor for detecting the early stages of colonization would be very useful. "

Researchers have investigated the effects of organosilic nanoparticles of different sizes, concentrations and coatings on the surface to see if and how they interact with both C. albicans and with the immune cells in the blood.

They found that nanoparticles bound to fungal cells, but not toxic to them.

"They do not kill the germ, but we can make an anti-fungal particle by binding them to a known anti-fungal drug," Professor Traven said.

The researchers also showed that the particles associate with neutrophils – human white blood cells – in a similar way as they did C. albicans, remaining non-cytotoxic to them.

"We have found that these nano-particles, and with the inference of many different types of nanoparticles, can interact with cells of interest," Dr Corey said.

“We can actually change the surface properties by presenting different things; with that we can really change the interactions they have with these cells – that's quite significant. "

Dr Corey said that while nanoparticles are being explored in cancer treatment, the use of nanoparticle-based technologies in infectious diseases lags behind the field of nanomedicine cancer, despite the great potential for new treatments and diagnostics.

"The other unique thing about this study is that instead of using cells grown in culture, we also look at how the particles work in all human blood and with neutrophils extracted from fresh human blood," he said.

Professor Traven said the study benefited greatly from interdisciplinary collaboration.

"We have assembled laboratories with expertise in infection, microbiology and immunology with a laboratory that has engineering expertise to do state-of-the-art experiments," she said.


First author of the study, Ph.D. student Vidishiri Kesarvani, co-supervised by Dr Corey and Professor Traven, crossed disciplinary boundaries highly efficiently and was instrumental in the study. Professor Steven Kent of the Department of Microbiology and Immunology at the University of Melbourne developed the assays to investigate the association between nanoparticles and immune cells from fresh human blood.

Read the full paper at ACS Applied Interfaces and Materials, entitled Characterization of key bio-nano interactions between Organosilica nanoparticles and Candida albicans.

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