Antibiotic resistance has been a growing public health concern. According to the Centers for Disease Control and Prevention (CDC), drug-resistant infections account for 2 million infections and lead to 23,000 deaths in the US and around 700,000 people worldwide per year.
According to Thomas Webster, a professor of Chemical Engineering at the Northeastern University, microscopic particles, manufactured by those antibiotic-resistant bacteria, could replace traditional antibiotics and provide a solution to the crisis. Webster and his colleagues are using bacteria to produce nanoparticles. They have found that these nanoparticles are particularly effective at killing whatever type of cell was used to create them, including strains of bacteria that are resistant to traditional antibiotics. Nanoparticles can destroy cells by smothering them from outside or disrupting cellular functions from within, owing to their small size.
The researchers are unaware as to why nanoparticles target their creators. David Medina, a doctoral student in Webster’s lab, says the bacteria may be misidentifying the nanoparticles as “friendly.” Bacterial cells can recognise one another, coexist, and cooperate with their own kind. They may act to fight off something that registers as foreign. When bacteria make nanoparticles, they coat them in a thin halo of protein. That protein layer may be making other bacteria of the same species flag them as “friendly”. The lab has been working with nanoparticles for two decades. Nanoparticles have many medicinal uses. Thus, Medina decided to see if they would be able to kill bacteria. He grew colonies of cells, mixing in metallic salts for them to process, and purified the results into nanoparticles. Then he mixed those with a different species of bacteria, to see if the nanoparticles could kill them. However, one day, by mistake, he mixed them with the same species. The nanoparticles effectively killed the bacteria.
“David discovered that if we program MRSA (an antibiotic-resistant Staphylococcus bacteria) to make a nanoparticle, that nanoparticle can actually selectively kill MRSA,” Webster says. “And we’re seeing that across the whole spectrum. If you took a breast cancer cell and you programmed that cell to make a nanoparticle, that nanoparticle is more selective at killing breast cancer cells than the healthy cells that are in your body. That was totally unexpected.”
Shahjadi Jemim Rahman