The discovery of antibiotics has been one of the most important discoveries of modern medicine, as it has dramatically reduced the number of deaths from infectious disease. However, decades of misuse has allowed bacteria to evolve defenses against these drugs, creating deadly "superbugs," such as MRSA. The medical community has warned that if this trend continues, the world will head into a "post-antibiotic era" and have essentially the same challenges with infectious disease as before penicillin's discovery.
Scientists are hard at work trying to find new ways of fighting back against these drug-resistant infections, and a team from the National Physical Laboratory (NPL) in the U.K. has discovered that a protein in breast milk, previously known for boosting immunity in newborns, could be used to develop a new drug capable of fight these superbugs. The results were published in Chemical Science.
Lactoferrin is a Y-shaped molecule, with each arm reaching about 2 nanometers in length. The team used this shape to their advantage, engineering the molecules to self-assemble into a capsule. The capsules then surround harmful bacteria and pierce the membrane, killing them.
"To monitor the activity of the capsules in real time we developed a high-speed measurement platform using atomic force microscopy," co-author Hasan Alkassem said in a news release. "The challenge was not just to see the capsules, but to follow their attack on bacterial membranes. The result was striking: the capsules acted as projectiles porating the membranes with bullet speed and efficiency."
When trying to treat any kind of infection, it's important to target the microbes that are causing the infection while minimizing damage to the healthy cells. These lactoferrin capsules are able to do that by essentially acting like a virus, targeting just the bacteria based on surface proteins on the membrane.
"Antimicrobial resistance is an increasing public health threat which requires a strong and coordinated response," added NPL's Director of Research, Jason Crain, who was not involved in the research. "This work demonstrates the power of combining physics and engineering principles with innovative measurement methods to create new strategies for tackling the problem. It is exactly the sort of high priority problem that the National Physical Laboratory should be active in addressing in collaboration with others."
Beyond the potential to curb antibiotic resistance, the researchers speculate they could engineer these pseudo-virus capsules to perform other tasks as well, like delivering medicine or performing gene therapy. This could be used to treat conditions like cancer, cystic fibrosis, and muscular dystrophy.
It will still be quite a while before this technique finds its way into clinical practice, but it represents an exciting step to address severe public health problems we are facing.
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