Preparing natural biocomposites of N-quaternary chitosan with antibacterial activity to reduce consumption of antibacterial drugs.

In this work, in order to prepare biocomposites of ciprofloxacin- montmorillonite/N,N,N-triethyl chitosan (CMC/TEC and CMC׳/TEC), ciprofloxacin was intercalated into the Na+-montmorillonite layers in two different pHs and coated with N,N,N-triethyl chitosan. XRD and FT-IR data demonstrated that ciprofloxacin (CIP) diffused among the layers of montmorillonite. The prepared biocomposites were further characterised by TG, SEM, BET, DSC, and disk diffusion method to investigate antibacterial activity against Staphylococcus aureus as well. Coated composites with N,N,N-triethyl chitosan possessed efficiency of the drug encapsulation, and controlled the release of drug from the biocomposites in comparison with composites without N,N,N-triethyl chitosan. Study of antibacterial activities of two biocomposites of CMC1/TEC and CMC2/TEC with lower release rates and lower concentrations of CIP than other biocomposites revealed that likely N,N,N-triethyl chitosan could considerably help to reduce the consumption of ciprofloxacin. By doing more researches on other bacterial strains and performing advanced tests on our own biocomposites, N,N,N-triethyl chitosan can probably be proved as a suitable candidate for a substitute in biomedical activities.

Study on montmorillonite/insulin/TiO2 hybrid nanocomposite as a new oral drug-delivery system.

This study was conducted in two main stages. In the first stage, drug-loaded montmorillonite nanocomposites were prepared by intercalation of insulin into the montmorillonite layers in acidic deionized (DI) water. In the second stage, to increase the release of insulin from the prepared nanocomposites they were coated with TiO2, an inorganic porous coating, by using titanium (IV) butoxide, as precursor. The prepared nanocomposites were characterized by FT-IR, XRD, FE-SEM, BET, DLS and Zeta potential analysis. After investigating the release behaviour of the nanocomposites by UV-Vis absorbance technique, the results revealed that incorporation of porous TiO2 coating increased the drug entrapment noticeably, and decreased the amount of drug release, so that nanocomposites without and with TiO2 coating released the drug after 60min and 22h in pH7.4, respectively. These results could be used in converting the insulin utilization from injection to oral.

Synthesis and characterization of insulin/zirconium phosphate@TiO2 hybrid composites for enhanced oral insulin delivery applications.

In this work, a series of composites of insulin (Ins)/zirconium phosphate (ZrP) were synthesized by intercalation method, then, these composites were coated with TiO2 by sol-gel method to prepare Ins/ZrP@TiO2 hybrid composites and the drug release of the composites was investigated by using UV-Vis spectroscopy. Ins/ZrP (10, 30, 60 wt%) composites were prepared by intercalation of insulin into the ZrP layers in water. Then Ins/ZrP composites were coated with different amounts of TiO2 (30, 50, 100 wt %) by using titanium tetra n-butoxide, as precursor. Formation of intercalated Ins/ZrP and Ins/ZrP@TiO2 hybrid composites was characterized by FT-IR, FE-SEM, BET and XRD analysis. Zeta potential of the optimized Ins/ZrP@TiO2 hybrid composite was determined -27.2 mV. Cytotoxic effects of the optimized Ins/ZrP@TiO2 hybrid composite against HeLa and Hek293T cell lines were evaluated using MTT assay and the results showed that designed drug delivery system was not toxic in biological environment. Compared to the Ins/ZrP composites, incorporation of TiO2 coating enhanced the drug entrapment considerably, and reduced the drug release. The Ins/ZrP composites without TiO2 coating released the whole drug after 30 min in pH 7.4 (phosphate buffer solution) while the TiO2-coated composites released the entrapped drug after 20 h. In addition to increasing the shelf life of hormone, this nanoencapsulation and nanocoating method can convert the insulin utilization from injection to oral and present a painless and more comfortable treatment for diabetics.

Destructive adsorption of Diazinon pesticide by activated carbon nanofibers containing Al2O3 and MgO nanoparticles.

We report the destructive adsorption of Diazinon pesticide by porous webs of activated carbon nanofibers containing Al2O3 and MgO nanoparticles. The results show that, the presence of Al2O3 and MgO nanoparticles in the activated carbon nanofibers increases the amount of destructively adsorbed Diazinon pesticide by activated carbon nanofibers. Moreover, type, amount, and specific surface area of metal oxide nanoparticles affect the adsorption rate as well as the total destructively adsorbed Diazinon. Liquid chromatography proved the degradation of Diazinon by chemical reaction with Al2O3 and MgO nanoparticles. Liquid chromatography-mass spectrometry showed that the main product of reaction between Diazinon and the metal oxides is 2-isopropyl-6-methyl-4-pyrimidinol with less toxicity than Diazinon.