Abstract

Introduction: Among different 2-D nanostructures, molybdenum disulfide (MoS2) has shown great potential as a good candidate in drug delivery systems. However, their biocompatibility and water dispersibility are the main issues for these purposes. With the aim of improving the MoS2 dispersibility, a novel drug delivery system based on polymer-modified MoS2 nanosheets was successfully prepared and characterized.

Methods: In this study, MoS2 nanosheets were prepared using a simple oleum treatment exfoliation approach and then modified by grafting thermos-responsive polymer N- isopropylacrylamide (NIPAM) and polyethylene glycol (PEG). The structural and morphological properties of the MoS2/NIPAM/ PEG nanosheets were characterized via Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier- Transform Infrared Spectroscopy (FTIR), and Thermogravimetric analysis (TGA/DSC). Initially, the adsorption behavior of the grafted nanoadsorbent was assessed for sorption of doxorubicin as an anticancer drug model. The influence of various parameters such as pH, temperature, and contact time was evaluated. Different kinetic and isotherm models were employed to investigate the (DOX) adsorption mechanism.

Results: The obtained results revealed that the DOX adsorption onto the MoS2/NIPAM/ PEG followed the Langmuir isotherm and pseudo-second-order models. In the next step, polymer grafted MoS2 nanosheets were used as thermos-sensitive drug nanocarriers for near-infrared (NIR) photothermal therapy. The combination of chemotherapy and photothermal therapy was also investigated, which indicated a remarkable improvement of cell apoptotic rate compared to monotherapy. Also, MTT assays showed that the MoS2/NIPAM/ PEG had high biocompatibility.

Conclusion: The novel thermo-responsive MoS2/NIPAM/ PEG showed great potential for targeted and controlled drug delivery.

Keywords: Molybdenum disulfide, N-isopropylacrylamide, cytotoxicity, doxorubicin, photothermal therapy, monotherapy.

Graphical Abstract