Researchers at the Moscow Institute of Physics and Technology (MIPT) have demonstrated the use of iron-based MOX MIL-100 nanoparticles as carriers for a photodynamic approach to eliminate intracellular chlamydia parasites. The method relies on active oxygen generated under visible red light to attack dormant forms of Chlamydia trachomatis that typically resist conventional antibiotics. This finding was shared by the university’s press service with socialbites.ca.
A major hurdle in treating intracellular infections is that bacteria shield themselves inside host cells, evading both antibiotics and the immune system. Chlamydia trachomatis is one such parasite, but several others, including the agents responsible for tuberculosis and listeriosis, also inhabit intracellular spaces. While some antibiotics can enter cells, a dormant state in chlamydia presents an additional challenge because a metabolically inactive bacterium is less susceptible to the actions of drugs aimed at disrupting replication or vital activity.
In the new study, the team prepared MOX MIL-100 nanoparticles composed of iron ions and trimesic acid. These particles are touted for low toxicity, biodegradability, biocompatibility, and chemical stability in aqueous environments, making them suitable as a drug container. The pores of the framework were loaded with methylene blue dye, an antibacterial agent that participates in the formation of reactive oxygen species when illuminated by red-range visible light. This reactive oxygen production damages the structural integrity of the parasite.
Experiments conducted on macrophages infected with chlamydia revealed that the nanoparticles could not only penetrate the infected cells but also reach the proximity of the bacteria, enabling targeted action within the cellular environment.
According to the researchers, most oxygen radicals produced in conjunction with the photosensitizer have a short lifespan and range, which confines the damage to nearby bacterial cells and minimizes harm to distant cellular structures such as the host cell nucleus. The team emphasizes that the MOX MIL-100 nanoparticles enable precise delivery of the photosensitizer to debris from chlamydial infections, allowing a photodynamic approach to destroy these bacteria within an infected host cell for the first time, as described by MIPT specialists involved in the project.
Future treatment strategies envision suspensions of these nanoparticles paired with the photosensitizer being administered dropwise into chlamydia-infected mucosal tissues. Subsequent irradiation with far-red light, which penetrates tissue to a depth of about 2 centimeters, would be delivered via light guides. This approach already finds application in gynecological procedures and could potentially be extended to other mucosal sites where chlamydial infection occurs.
Collaborative efforts in this study involved teams from the MIPT Special Cell Technologies Laboratory and colleagues from Moscow State University, MV Lomonosov named NICEM, and the Gamaleya Federal Research Center for Physical and Chemical Medicine, among others. The participating institutions also include the Paris Institute for Porous Materials (IMAP, Ecole Normale Supérieure), highlighting an international dimension to the research on porous materials and their biomedical applications.
These findings underscore a broader trend in the field of antimicrobial therapy: leveraging targeted nanomaterials to deliver photosensitizers directly to intracellular pathogens and activating them with light to generate localized oxidative damage. While clinical translation will require further validation, the demonstrated ability to reach intracellular sanctuaries and to activate a selective, light-driven antiviral effect marks a significant step toward new options for tackling stubborn intracellular infections in patients.