NIPAM/PEG/ MoS2 Nanosheets for Dual Triggered Doxorubicin Release and Combined Chemo-photothermal Cancer Therapy.

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.

Synthesis and characterization of poly[1-(N,N-bis-carboxymethyl)amino-3-allylglycerol-co-dimethylacrylamide] grafted to magnetic nano-particles for extraction and determination of letrozole in biological and pharmaceutical samples.

In this paper, a new method is reported for the surface grafting of poly[1-(N,N-bis-carboxymethyl)amino-3-allylglycerol-co-dimethylacrylamide] onto magnetic nano-particles modified by 3-mercaptopropyltrimethoxysilane. The grafted nano-sorbent was characterized by Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis, and scanning electron microscopy. Agglomerated nano-particles with multi-pores were used for extraction and determination of trace letrozole in human biological fluids and pharmaceutical samples. The profile of the letrozole uptake by the magnetic nano-sorbent reflected good accessibility of the active sites in the grafted polymer. Scatchard analysis revealed that the sorption capacity of the functionalized nano-sorbent was 6.27 µmol g(-1) at an optimum pH of 4. The equilibrium adsorption data of letrozole by grafted magnetic nano-sorbent were analyzed by Langmuir, Freundlich, Temkin and Redlich-Peterson models. Conformation of the experimental data in the Langmuir isotherm model indicated the homogeneous binding site of functional polymer-grafted magnetic nano-sorbent surface. Nearly 89% of letrozole was released in simulated gastric fluid, pH 1.2, in 2h and 79% in simulated intestinal fluid, pH 7.4, in 30 h. These results show the utility of the letrozole loaded- polymer grafted magnetite nano-particles for enteric drug delivery.