Enzymatic Biodegradability of Pristine and Functionalized Transition Metal Dichalcogenide MoS₂ Nanosheets

Abstract

2D transition metal dichalcogenide MoS2 nanosheets are increasingly attracting interests due to their promising applications in materials science and biomedicine. However, their biocompatibility and their biodegradability have not been thoroughly studied yet. Here, we investigated the biodegradability of exfoliated pristine and covalently functionalized MoS2 (f-MoS2). First, biodegradability of these nanomaterials was evaluated using plant horseradish peroxidase and human myeloperoxidase. The results revealed that the enzymatic degradability rate of MoS2 and f-MoS2 was slower than in the case of the simple treatment with H2O2 alone.In parallel, high biocompatibility of both pristine and f-MoS2 nanosheets was found up to 100 µg mL -1 both in cell lines (HeLa and Raw264.7) and primary immune cells. In addition, no immune cell activation and minimal pro-inflammatory cytokine release were observed in RAW264.7 and human monocyte-derived macrophages, suggesting a negligible cellular impact of such materials. Furthermore, the effects of degraded MoS2 and partially degraded f-MoS2 products on cell viability and activation were studied in cancer and immune cells. A certain cytotoxicity was measured at the highest concentrations. Finally, to prove that the

Degradation behaviors and mechanisms of MoS2 crystals relevant to bioabsorbable electronics

“…where the molybdate ion (MoO 4 2− ) is the main Mocontaining byproduct, which has been confirmed by inductively coupled plasma-mass spectrometry (ICP-MS) measurements 20,26,27 . Note that Na + and K + ions in the PBS solution may lead to lattice distortions of MoS 2 and the formation of Na 2 S (from 2H-MoS 2 to 1T-NaMoS 2 and then to soluble Na 2 S), further accelerating the degradation process 20 .…”

“…Thermal oxidation and anisotropic etching of two-dimensional (2D) MoS 2 in air have been previously reported; however, the degradation environment differs substantially from that in biofluids not only with respect to the reaction temperature and speed but also with respect to the reactants and products [12][13][14][15][21][22][23][24][25] . Other studies have reported the dissolution of chemically/ mechanically exfoliated MoS 2 nanosheets in aqueous solution; however, nanosheets dispersed in solution have little relevance to electronics 26,27 . Fundamental studies, including the interaction between monolayer MoS 2 crystals and biofluids, the morphological evolution, and the role of grain boundaries (GBs) and point defects during degradation, have yet to be adequately conducted 6,[26][27][28][29] .…”

“…Other studies have reported the dissolution of chemically/ mechanically exfoliated MoS 2 nanosheets in aqueous solution; however, nanosheets dispersed in solution have little relevance to electronics 26,27 . Fundamental studies, including the interaction between monolayer MoS 2 crystals and biofluids, the morphological evolution, and the role of grain boundaries (GBs) and point defects during degradation, have yet to be adequately conducted 6,[26][27][28][29] . This study investigates the degradation behaviors and mechanisms of monolayer MoS 2 crystals with different crystallographic misorientation angles in phosphatebuffered saline (PBS) solution.…”

Silicene: Wet‐Chemical Exfoliation Synthesis and Biodegradable Tumor Nanomedicine

“…The nanosheets of the original silicene were flat, clear, and transparent. [22] XPS characterization was carried out to measure the oxidized silicon species after treating the SNSs suspension in 3 and 14 days (Figure 2f Figure S4d, Supporting Information), the peaks of Si oxidation states at 102.3, 103.54, and 105.8 eV were assigned, respectively, to Si-OH (-OH terminated), SiO x (-O terminated), and SiO-OH x (-OOH terminated). It could be found that the degradation was evident as indicated by the substantial shape changes in 7 days, and the original morphology of SNSs was completely disrupted and only very few sheet-like objects could be observed in 14 days (Figure 2e).…”

2D Nanomaterials for Cancer Theranostic Applications

“…However, certain types of rationally designed 2D nanomaterials are also considered to be biodegradable. [153] For example, it has been reported that GO and Nb 2 C nanosheets undergo horseradish peroxidase-dependent oxidative degradation, although their degradation speed may not be fast. [27,154] MoS 2 is kinetically and thermodynamically unstable in the physiological environment and can be oxidized into water-soluble Mo VI -oxide species (e.g., MoO 4 2− ), which have been shown to be readily excreted from mice by renal and fecal pathways.…”