Zeolite Nanoparticles Loaded with 2-Methoxystradiol as a Novel Drug Delivery System for the Prostate Cancer Therapy

The estrogen metabolite 2-methoxyestradiol (2ME) is a promissory anticancer drug mainly because of its pro-apoptotic properties in cancer cells. However, the therapeutic use of 2ME has been hampered due to its low solubility and bioavailability. Thus, it is necessary to find new ways of administration for 2ME. Zeolites are inorganic aluminosilicates with a porous structure and are considered good adsorbents and sieves in the pharmaceutical field. Here, mordenite-type zeolite nanoparticles were loaded with 2ME to assess its efficiency as a delivery system for prostate cancer treatment. The 2ME-loaded zeolite nanoparticles showed an irregular morphology with a mean hydrodynamic diameter of 250.9 ± 11.4 nm, polydispersity index of 0.36 ± 0.04, and a net negative surface charge of -34 ± 1.73 meV. Spectroscopy with UV-vis and Attenuated Total Reflectance Infrared Fourier-Transform was used to elucidate the interaction between the 2ME molecules and the zeolite framework showing the formation of a 2ME-zeolite conjugate in the nanocomposite. The studies of adsorption and liberation determined that zeolite nanoparticles incorporated 40% of 2ME while the liberation of 2ME reached 90% at pH 7.4 after 7 days. The 2ME-loaded zeolite nanoparticles also decreased the viability and increased the mRNA of the 2ME-target gene F-spondin, encoded by SPON1, in the human prostate cancer cell line LNCaP. Finally, the 2ME-loaded nanoparticles also decreased the viability of primary cultures from mouse prostate cancer. These results show the development of 2ME-loaded zeolite nanoparticles with physicochemical and biological properties compatible with anticancer activity on the human prostate and highlight that zeolite nanoparticles can be a good carrier system for 2ME.

Porous stainless-steel fibers supported CuCeFeOx/Zeolite catalysts for the enhanced CO oxidation: Experimental and kinetic studies

To develop novel catalysts of high-performance and cost-effectiveness, and to investigate the reaction kinetics of CO oxidation, ternary CuCeFeO_x catalysts supported on zeolite/PSF (porous stainless-steel fibers) were synthesized for the first time. Effects of different Ce/Fe ratios, loading amounts, calcination temperatures, and reaction kinetics were investigated. Remarkably improved catalytic performance was achieved in the PSF-supported catalysts compared to the granular ones, owing to the increased mass/heat transfer efficiency and the high dispersion of active metal oxide species anchored on the zeolite layer. The Cu₃Ce₁₂Fe₄-400 sample exhibited the best catalytic activity with a temperature difference in T₉₀ of almost 40 °C lower than the worst one. Characterization results from XRD, FTIR, TEM, XPS, H₂-TPR, etc. revealed that the promoted reducibility of metal oxides and formation of more oxygen vacancies significantly contributed to the enhanced catalytic activity. Furthermore, a generalized rate expression was derived from intrinsic and macro kinetic studies by assuming the conversion of CO to CO₂ as the rate-determining step, in which CO oxidation over the PSF-supported catalysts followed the pseudo-first-order kinetic established by the Langmuir-Hinshelwood type mechanism.

Design of an environmentally friendly fuel based on a synthetic composite nano-catalyst through parameter estimation and process modeling

In this paper, oxidative desulfurization (ODS) process is studied for the purpose of removing the sulfur components from light gas oil (LGO) via experimentation and process modeling. A recently developed (by the authors) copper and nickel oxide based composite nano-catalyst is used in the process. The ODS experiments are conducted in a batch reactor and air is used as an oxidizer under moderate operation conditions. Determination of the kinetic parameters with high accuracy is necessary of the related chemical reactions to develop a helpful model for the ODS operation giving a perfect design of the reactor and process with high confidence. High conversion of 92% LGO was obtained under a reaction temperature of 413 K and reaction time of 90 min for synthesized Cu Ni /HY nano-catalyst. Here model based optimization technique incorporating experimental data is used to estimate such parameters. Two approaches (linear and non-linear) are utilized to estimate the best kinematic parameters with an absolute error of less than 5% between the predicted and the experimental results. An environmentally friendly fuel is regarded the main goal of this study, therefore the optimization process is then employed utilizing the validated model of the prepared composite nano-catalyst to get the optimal operating conditions achieving maximum conversion of such process. The results show that the process is effective in removing more than 99% of the sulfur from the LGO resulting in a cleaner fuel.

Application of fly ash-based materials for stabilization/solidification of cesium and strontium

Coal fly ash, as a solid waste produced from coal-fired power plants, was recycled for synthesis of zeolite A and geopolymer which were used for stabilization/solidification of Cs⁺ and Sr²⁺ from aqueous solutions. Specifically, the sorption data was successfully fitted by kinetic and thermodynamic models. The microstructure changes of zeolite A after loading Cs⁺ and Sr²⁺ were explored using XRD, FTIR, Raman, TG-DTA, and N₂ adsorption/desorption isotherm. The solidification of the spent zeolites using geopolymer was conducted and evaluated. It was found that pseudo-second sorption mechanism was predominant and, according to the Boyd equation, film diffusion seemed to govern the sorption process. The maximum sorption capacities on Cs⁺ and Sr²⁺ based on Langmuir model were 2.12 and 1.93 mmol/g, respectively. During ion exchange with Cs⁺ and Sr²⁺, Cs⁺ was inclined to go through the window to occupy the position of eight-member ring, while the Sr²⁺ was more likely to replace the Na⁺ in the six-member ring, thereby easily leading to the different changes of zeolite structure. In addition, geopolymer could be a promising matrix for the treatment of radioactive waste because the leaching fraction greatly decreased after solidification by geopolymer. Therefore, the recycling of coal fly ash for radioactive waste disposal could achieve the concept of disposal waste with waste and recycling, which could greatly contribute to the sustainable development of society.

Alkaline earth ion exchange study of pure silica LTA zeolites using periodic first-principles calculations

The Linde Type A (LTA) zeolite capability to exchange alkaline earth ions is analyzed using DFT calculations, considering the systems to be in water and vacuum, investigating the LTA's potential as a material for radioactive decontamination processes.

Zeolites and zeolite-based materials in extraction and microextraction techniques

This review presents an overview of the current status of zeolites and zeolite-based materials used in extraction and microextraction techniques with reference to recent applications and highlight some of the novel advances.

Communication: First-principles evaluation of alkali ion adsorption and ion exchange in pure silica LTA zeolite

Using first-principles calculations, we studied the adsorption of alkali ions in pure silica Linde Type A (LTA) zeolite. The probability of adsorbing alkali ions from solution and the driving force for ion exchange between Na⁺ and other alkali ions at the different adsorption sites were analyzed. From the calculated ion exchange isotherms, we show that it is possible to exchange Na⁺ with K⁺ and Rb⁺ in water, but that is not the case for systems in a vacuum. We also demonstrate that a solvation model should be used for the accurate representation of ion exchange in an LTA and that dispersion interactions should be introduced with care.

Novel Zeolite-5A@MOF-74 Composite Adsorbents with Core-Shell Structure for H2 Purification

Hydrogen is considered as one of the most important clean and renewable energy sources for a sustainable energy future. However, its efficient and cost-effective purification still remains challenging. In this work, we report the development of novel zeolite@metal-organic framework (MOF) composites comprised of MOF-74 and zeolite-5A with core-shell structure for efficient purification of H₂. The composites were synthesized hydrothermally through the addition of zeolite particles with and without carboxyl functional groups to the MOF synthesis solution. The zeolite/MOF weight ratio was varied systematically to find the optimum composition based on the adsorption performance. The formation of zeolite@MOF composites was confirmed by various characterization techniques. Single-component adsorption isotherms of CO₂, CO, CH₄, N₂, and H₂ over composites were measured at 25 °C to determine their equilibrium adsorption capacity. It was found that the zeolite-5A@MOF-74 with weight ratio of 5:95 exhibited a similar morphology to that of pristine MOF-74, but with higher surface area and total pore volume. Moreover, this composite showed 20-30% increase in CO₂, CO, CH₄, and N₂ uptake than the bare MOF, which could be attributed to the formation of new mesopores at the MOF-zeolite interface. The estimated selectivity values for CO₂/H₂, CO/H₂, CH₄/H₂, and N₂/H₂ were higher than those of the zeolite and/or MOF. Our results also indicated that surface modification of zeolite prior to composite formation does not enhance the adsorption capacities of the composites. Overall, the findings of this study suggest that the zeolite-5A@MOF-74 composites with core-shell structure are promising candidates for industrial H₂ purification processes.

Preparation and in vitro evaluation of 5-flourouracil loaded magnetite-zeolite nanocomposite (5-FU-MZNC) for cancer drug delivery applications

In this work, super paramagnetic magnetite nanoparticles were synthesized onto/into zeolite, then loaded with anti-cancer drug 5-fluorouracil (5-FU). The physical properties of the prepared nanocomposite and drug loaded nanocomposite were characterized using different techniques. The drug loading and releasing behavior of the magnetic nanocarrier was investigated and the drug-loaded nanoparticles exhibited a sustained release of drug without any burst release phenomenon. Furthermore, 5-FU loaded MZNC were evaluated for its biological characteristics. The functional 5-FU-MZNC has been triggered intra-cellular release of the cancer therapeutic agent 5-fluorouracil (5-FU). Cytotoxic effects of 5-FU loaded MZNC on human gastric carcinoma (AGS) cells were determined by real time cell analysis and colorimetric WST-1 cell viability assay. Apoptosis of cells was further investigated by Annexin-V staining which indicates the loss of cell membrane integrity. According to our results, 5-FU-MZNC showed a concentration-dependent cell proliferation inhibitory function against AGS cells. Morphologic and apoptotic images were consistent with the cytotoxicity results. In conclusion, 5-FU loaded MZNC efficiently inhibit the proliferation of AGS cells in vitro through apoptotic mechanisms, and may be a beneficial agent against cancer, however further animal study is still required.