Phages are viruses that thrive by infecting bacteria, and controlled phage therapy has long been viewed as a potential replacement for antibiotics. But where antibiotics present the problem of the bacteria they target mutating into dangerous resistant strains, phages pose a risk because of their own rapid evolution, although these risks are poorly understood. However, new research suggests that it may be possible to mitigate these risks. Certain phages are left to nature and are capable of detecting and destroying certain types of bacteria.
Controlled phage therapy against infections
Controlled phage therapy can therefore target resistant bacteria while avoiding potential unintended consequences. But here it is only the search that interests researchers by delivering a load of gold nanoparticles with the phages. These use light to destroy both the targeted bacteria and their phages at once. So you can imagine the phage as a guidance system and the particles as a warhead of this special antibacterial guided missile.
“We conjugated the phages with gold nanoparticles,” explains Irene Chen from UC Santa Barbara in a press release. If you thought conjugation only had to do with verbs, this will amaze you. It also means to connect or couple. “When these nanoparticles are excited by light, they convert the energy of light into heat, resulting in very high local temperatures.”
The so-called “Phanorod” combinations of nanorods and phages were added to test tube cultures of mammalian cells with an added bacterial biofilm. The scientists then exposed light to near-infrared wavelengths to trigger the all-important excitation. The resulting heat kills both the bacteria and the phage itself.
New research results
In experiments, the Phanorods successfully destroyed the potent human pathogensE. coli Bakterien, P. aeruginosa and V. cholerae. However, it's important to note that the Phanorods also destroyed 20 percent of the mammalian cells in the culture, which the research classifies as a "low damage rate."
In addition to the unpredictable nature of the uncontrolled evolution of phages, there are other problems with their historical use. They may potentially contain toxins. For this reason, it is difficult to assess the success of the treatment. “You may see that it works completely or that it completely fails, but you don't have the kind of dose response that you want,” explains Chen. However, this new controlled approach to phage therapy could potentially alleviate these problems as well.
The team will study more phages to target more types of bacteria, as well as investigate photothermal methods to treat multiple bacterial infections at once. However, the work is still in the research stage and there is currently no evidence of clinical application.
The research team has theStudy on the sideProceedings of the National Academy of Sciences published. This can be read online for free.
