Comparative removal of hazardous cationic dyes by MOF-5 and modified graphene oxide.

Among cationic dyes, malachite green (MG) is commonly used for dying purposes and also as an inhibitor in aquaculture, food, health, and chemical industries due to its cytotoxic effects. Therefore, MG removal is essential to keep the ecosystem and human health safety. Adsorption is a viable and versatile option and exploring efficient adsorbents have high priority. Herein, MOF-5 and aminated corn Stover reduced graphene oxide (ACS-RGO) of typical adsorbents of metal-organic-frameworks (MOFs) and carbon-based classes were studied for MG removal. MOF-5 and ACS-RGO had a specific surface area and total pore volume of 507.4 and 389.0 m2/g, and 0.271 cm3/g and 0.273 cm3/g, respectively. ACS-RGO was superior for MG adsorption and the kinetic rate coefficient for ACS-RGO was ~ 7.2 times compared to MOF-5. For ACS-RGO, MG removal remained high (> 94%) in a wide range of pH. However, dye removal was pH-dependent for MOF-5 and increased from ~ 32% to ~ 67% by increasing pH from 4 to 12. Increasing dye concentration from 25 mg/L to 100 mg/L decreased adsorption by MOF-5 and ACS-RGO for ~ 30% and 7%, respectively. Dye removal was evident in a few tens of seconds after adding ACS-RGO at doses above 0.5 g/L. A significant loss of 46% in adsorption was observed by decreasing MOF-5 mass from 1 to 0.1 g/L. ACS-RGO removed MG in multilayer with an exceptional adsorption capacity of 1088.27 mg/g. In conclusion, ACS-RGO, and MOF-5 showed promising kinetic rates and adsorption capacities toward MG.

Molecular dynamics simulation of drug delivery across the cell membrane by applying gold nanoparticle carrier: Flutamide as hydrophobic and glutathione as hydrophilic drugs as the case studies.

In this study, molecular dynamics simulation is applied to investigate drug transport in both pure state and conjugated with neutral gold nanoparticle (AuNP) as a drug carrier inside dipalmitoylphosphatidylcholine (DPPC) membrane. Flutamide (Flu) as a hydrophobic and Glutathione (GSH) as a hydrophilic anticancer drug are selected as the case studies. Dynamics of each drug including adhesion on and penetration into the cell membrane are investigated. Pure and conjugated form of drugs inside the water and near the membrane are studied. Simulation results show that the interaction between drug molecules and DPPC changes after drug conjugating with AuNP. GSH, as a hydrophilic drug, intends to remain above the membrane bilayer and after conjugating with AuNP diffuses inside DPPC. However, hydrophobic Flu molecule likes to diffuse inside DPPC, but after conjugating with AuNP, its diffusion inside the lipid bilayer decreases, and its retention time at the surface of DPPC increases. Presence of Flu-NP at the surface of DPPC could enhance its impact on blocking dihydrotestosterone binding at androgen receptors resulting in tumor cell growth arrest. In addition, the tendency of GSH-NP for diffusion to the DPPC is a positive factor for the successful transport of heavy metals such as AuNP without rapid clearance through either the hepatobiliary pathway or the renal system. In conclusion, such MD simulation results may solve problems in nanomedicine translation and turn into a bridge toward maximizing targeting and minimizing nanotoxicity of metal NPs.

Multi-template molecularly imprinted polymer hybrid nanoparticles for selective analysis of nonsteroidal anti-inflammatory drugs and analgesics in biological and pharmaceutical samples.

The multi-template molecularly imprinted polymers reinforced with hybrid oxide nanoparticles were developed for the selective separation and determination of the trace level of naproxen (NPX), methocarbamol (MTH), and omeprazole (OMZ) simultaneously from biological and pharmaceutical samples. The polymers were constructed by magnetic core@shell molecularly imprinted polymer nanocomposite (Fe3O4/ZnO/CuO/MWCNT@MIP). An electrochemical sensor has been fabricated for this purpose. Fe3O4/ZnO/CuO/MWCNT nanocomposite was introduced to improve the electron transport capability and increase the sensor surface area, as well as enhance the electronic conductivity. The triple-template MIP-coated layer provides simultaneous selective identification of three analytes by using [Fe (CN)6]3-/4-as the redox probe. Electrochemical behavior of MTH, NPX, and OMZ on the modified electrode (Fe3O4/ZnO/CuO/MWCNT@MIP) by various techniques such as cyclic voltammetry, differential pulse voltammetry, and chronoamperometry was examined. The morphology of the modified and unmodified carbon paste electrodes was performed by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The average crystal size for fabricated nanoparticles obtained by calculating the X-ray diffraction technique was 17 nm in the Scherer method. The particle size which was determined by SEM was 48 nm. Some electrochemical parameters such as the diffusion coefficient and electron transfer coefficient were determined. The effect of many variables such as the pH and scan rate was also investigated. Under optimal conditions, the sensor is designed in the linear range 5.0 nM-100 µM and 5.0 nM-100 µM and 1.0 nM-130 µM with a detection limit of 1.5 nM, 1.0 nM, and 0.7 nM for measurement OMZ, NPX, and MTH, respectively. The relative standard deviation (RSD) of the five measurements was 1.21%, 2.23%, and 2.56% for NPX, MTH, and OMZ. Finally, the designed sensor was successfully used for simultaneous detection of target analytes in the real samples; tablets, water samples, and biological samples.