An all-in-one nanomaterial derived from rGO-MoS2 for photo/chemotherapy of tuberculosis

Abstract

A combination of therapeutic modalities has recently emerged as an alternative technique for combating Mycobacterium tuberculosis. Tuberculosis infections are difficult to treat due to the development of multi-antibiotic-resistant strains. Here, we report an all-in-one photoactive nanoagent with photothermal, photodynamic, and antimycobacterial properties. It was fabricated using polyorganophosphazene–graphene–MoS₂ loaded with isoniazid (IZN) and indocyanine green (ICG). The reduced graphene–MoS₂ was prepared by the L-cysteine-assisted solution-phase method. Furthermore, the fabrication was continued by functionalization of poly[bis(carboxyphenoxy)phosphazene] (PCPP) with IZN. After NIR-irradiation, ICG stacked rGO-MoS₂-PCPP-IZN generates heat and also produces singlet oxygen. The 2D nanostructures prevent ICG aggregation and maintain the stability of ICG. The cumulative IZN release, higher photothermal effect (180 s), and generation of singlet oxygen are attributed to the combined therapeutic modality. rGO-MoS₂-PCPP-IZN-ICG causes severe destruction of E. coli and B. subtilis membranes, and also shows good cytocompatibility. It inhibits Mycobacterial colonization and cell viability as assessed by flow cytometry. There is a higher peak shift for dead cell count after exposure to NIR-irradiation for 5 min. The combined modality effect was due to the penetration of MoS₂, physical cutting of the cell membrane, hyperthermia, membrane damage by IZN, and singlet oxygen generation. Finally, the all-in-one photoactive nanoagent effectively damaged the Mycobacterium tuberculosis cell membrane with 100% efficiency in a lesser time of light exposure.