Scientists designed osmium-based compounds to absorb green light and halt drug-resistant bacteria.
Researchers at the Indian Institute of Technology (BHU) in Varanasi developed a new class of light-responsive metal-based antibiotics. They designed the compounds to combat biofilm-forming pathogens and accelerate wound healing.
Many bacteria protect themselves within a slimy matrix known as a biofilm. The matrix shields the microbes and makes infections difficult to eliminate.
Led by Sudip Mukherjee and Samya Banerjee, the team synthesized three osmium-based complexes named Os1, Os2, and Os3 to overcome this defensive shielding.
The team evaluated the compounds against three pathogenic bacterial species widely used to probe antibacterial treatments and infections. These are Bacillus subtilis, Escherichia coli, and Staphylococcus aureus.
Among the tested substances, Os1 emerged as the most promising candidate. It showed potent light-activated antibiofilm activity against mature E. coli biofilms.
Treatment combining Os1 with green-light irradiation accelerated wound healing in tests on rats with E. coli-infected wounds. The compound proved non-toxic to specific human embryonic kidney cells, rat red blood cells, and a chicken egg model.
Doctors used bacteriophages—microscopic viruses that infect and kill bacteria—to fight infections a century ago, long before antibiotics became the standard treatment. Their medical use in Western countries declined following the arrival of antibiotics, inconsistent results from early treatments, and the onset of the Cold War.
Alexander Fleming discovered penicillin. In his 1945 Nobel Prize lecture, he warned that bacteria could develop resistance to antibiotics. That prediction proved correct as resistant strains emerged due to the overuse and misuse of these drugs.
Antibiotic resistance is projected to contribute to more than eight million deaths annually by 2050. Interest in phage-based treatments has been renewed.
Several countries, including the United States and some European Union members, have introduced programs offering personalized phage therapy to selected patients. Some programs use genetically modified phages.
Phage therapy is not routinely available as a treatment option in New Zealand due to regulatory hurdles and gaps in scientific understanding. Methods for studying and modifying phages can also be time-consuming, restricted to certain bacteria, or dependent on detailed knowledge of a phage genome.