Nanodiamonds Co-Localize with Mycobacterium tuberculosis in Foamy Macrophages of Infected Mouse Lungs

Background: Pulmonary tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis). Drug-resistant TB remains a major public health challenge and calls for new approaches to drug development. Targeted delivery of antibacterial agents using nanoscale carriers represents one such approach. A decisive factor for efficient targeting is the judicious selection of the carrier platform. Methods: In the present study, diamond nanoparticles were evaluated as a prospective vehicle for conveying anti-TB drugs to lung cells. Conventional and analytical transmission electron microscopy were used to analyze the localization of the nanodiamonds (NDs) in the lungs of M. tuberculosis-infected mice 30 days after nanoparticle administration and 44 days post-infection. Results: The study shows that the NDs co-localize with M. tuberculosis in foamy macrophages of the lung, residing in the same cellular compartments—phagosomes/phagolysosomes and lipid droplets. These in vivo results demonstrate a high degree of macrophage-specific accumulation of NDs relative to M. tuberculosis. Conclusions: Consequently, NDs can be considered a promising carrier for targeted delivery of anti-TB therapeutics to the lungs during TB-induced inflammation.