Fig. 1: Synthesis and characterization of MoS₂ nanoflowers with predefined atomic vacancies.

A Atomic arrangement of Mo and S in 2D MoS₂. Changing molybdenum: sulfur precursor ratio leads to the formation of MoS₂ with different degrees of atomic vacancies. Transmission electron microscopy (TEM) images show MoS₂ nanoflower assembly consisting of multiple individual MoS₂ nanosheets. X-ray diffraction (XRD) peaks of MoS₂ nanoflowers (002, 100, 110) show the presence of hexagonal crystal structure. B X-ray photoelectron spectra (XPS) show the binding energies (BE) for Mo and S within MoS₂ nanoflowers. 1 T (trigonal prismatic) and 2H phase (hexagonal symmetry) within the trigonal prismatic MoS₂ crystal. C Cyclic voltagrams for MoS₂ coated electrode in comparison with standard uncoated electrode. The density of active sites calculated from these voltagrams are presented in the table in moles/g. The density of active sites increases with increasing sulfur precursor ratio. D The effect of MoS₂ nanoflowers concentration (with differing degree of atomic vacancies) on cell viability in hMSCs following 24 h of exposure. MoS₂ nanoflowers exhibit half-inhibitory concentration (IC₅₀) of ~400 µg/mL. (data represented as mean ± SD, with n = 4 biological replicates). E Cell membrane integrity in presence of MoS₂ was determined by monitoring release of LDH in media following 24 h of exposure. No significant effect of atomic vacancies is observed at lower concentration ( < IC₅₀) of MoS₂ nanoflowers.(data represented as mean ± SD, with n = 4 biological replicates). F Effect of atomic vacancies of MoS₂ nanoflowers (1:6) on cell cycle is determined after 72 h. (data represented as average cell population within each phase of the cell cycle, with n = 3 biological replicates). G Internalization of MoS₂ nanoflower (1:6) is evident from fluorescence images of cells after 24 h. Green: MoS₂ nanoflowers, Purple: actin cytoskeleton. Blue: DAPI, nucleus. H Cellular internalization of MoS₂ nanoflowers was determined using ICP-MS elemental analysis following 18 h of exposure to nanoflowers. The levels of Mo are plotted for hMSCs treated with and without MoS₂ nanoflowers. (Data represented as mean ± SD, with n = 3 biological replicates. Statistical significance was determined using one way ANOVA with post hoc Tukey test, *p < 0.05; **p < 0.01, ***p < 0.001).