Antibiotic resistance is an increasing threat to public health. In 2014, the World Health Organization warned that we are heading for a "post-antibiotic era," where infections that have been treatable for decades become life-threatening. While a main focus of research has been the development of new antibiotics, one team has focused on boosting the immune system as a key defense against antibiotic-resistant bacteria.

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The synthetic immune cells (pictured) have been shown to fight antibiotic-resistant E. coli.
Image credit: Tom Webster

Dr. Thomas J. Webster - the Art Zafiropoulo chair and professor of the Department of Chemical Engineering at Northeastern University in Boston, MA, and president of the US Society for Biomaterials - and colleagues have created synthetic immune cells, referred to as polymersomes.

These polymersomes can mimic the behavior of natural immune cells, according to the team, opening the door to a way to boost infection-fighting capability among individuals with compromised immune systems.

"They can significantly aid someone who has a failing immune system, or for someone who needs a little bit of help fighting a large number of bacteria or even viruses," Dr. Webster told Medical News Today.

"They are sort of like an extra boost of energy for our existing immune system, which most of us will need at least once in our lifetimes to fight a disease."

To create the initial prototype of these polymersomes, the team used a polymer that imitates natural cell membranes. When added to water-based solutions, the polymer self-assembles inside the cell.

Next, the researchers embedded silver nanoparticles inside the polymersomes, alongside ampicillin - an antibiotic used to treat infections caused by bacteria, including pneumonia, bronchitis and urinary tract infections (UTIs).

Polymersomes stopped growth of antibiotic-resistant E. coli

In a study published in the journal Nanoscale in January last year, the team tested the polymersomes against a type of ampicillin-resistant Escherichia coli.

Dr. Webster explained to MNT that the polymersomes attract and bond to the bacteria before releasing the silver nanoparticles inside them, delivering the drug at the same time.

In their study, the researchers found that the polymersomes effectively halted the growth of the E. coli. They put this effect down to the "synergistic activity" of both the nanoparticles and the ampicillin; the polymersomes had no effect on E. coli growth when the silver nanoparticles were absent.

The team is now working on creating synthetic immune cells incorporating lysosomes, which Dr. Webster described as "acidic capsules inside immune cells that kill bacteria."

The researchers hope to begin animal studies within the next 6 months, in which they will assess how effective the polymersomes are for identifying and fighting infection in rats. Additionally, they plan to enhance the polymersomes so they mimic natural immune cells more closely.

It is clear much more work is needed before these synthetic immune cells can be tested in humans, but the team has high hopes that they have the potential to combat a variety of bacterial infections, including those that are resistant to existing antibiotics.

Dr. Webster told MNT:

"I get very excited when I think about the possibility of creating synthetic immune cells that can help any patient - regardless of age or disease - live a more fulfilling, healthy lifestyle; we are just around the corner from that."

In an earlier article, Dr. Webster spoke to MNT about his and his team's work with nanosensors - a novel form of technology that aims to monitor accumulation of bacteria on implants and warn doctors when treatment is needed.