Bactericidal impact of Ag, ZnO and mixed AgZnO colloidal nanoparticles on H37Rv Mycobacterium tuberculosis phagocytized by THP-1Â cell lines

The purpose of this research project was to infection of human macrophages (THP-1) cell lines by H37Rv strain of Mycobacterium tuberculosis (H37RvMTB) and find out the ratio/dilution of mixture silver (Ag NPs) and zinc oxide nanoparticles (ZnO NPs) whose ability to eliminate phagocytized bacteria compared to rifampicin. The colloidal Ag NPs and ZnO NPs were synthesized and their characteristics were evaluated. The THP-1 cell lines were infected with different concentration of H37RvMTB. Next, the infected cells were treated with different ratios/dilutions of Ag NPs, ZnO NPs and rifampicin. The THP-1 were lysed and were cultured in Lowenstein-Jensen agar medium, for eight weeks. The TEM and AFM images of NPs and H37RvMTB were supplied. It is observed that Ag NPs, 2Ag:8ZnO and 8Ag:2ZnO did not have any anti-tubercular effects on phagocytized H37RvMTB. Conversely, ZnO NPs somehow eliminated 18.7 × 104 CFU ml−1 of H37RvMTB in concentration of ∼ 0.468 ppm. To compare with 40 ppm of rifampicin, ∼ 0.663 ppm of 5Ag:5ZnO had the ability to kill of H37RvMTB, too. Based on previous research, ZnO NPs had strong anti-tubercular impact against H37RvMTB to in-vitro condition, but it was toxic in concentration of ∼ 0.468 ppm to both of THP-1 and normal lung (MRC-5) cell lines. It also seems that 5Ag:5ZnO is justified because in concentration of ∼ 0.663 ppm of 5Ag:5ZnO, phagocytized H37RvMTB into the THP-1 had died without any toxicity effects against THP-1 and also MRC-5 cell lines. It is obvious that the mixture of colloidal silver and zinc oxide NPs with ratio of 5Ag:5ZnO would be trustworthy options as anti-tubercular nano-drugs in future researches.