نشریه پژوهش های شیمیایی و نانو مواد
سال دوم شماره 3 (پیاپی 7، پاییز 1402)

In this research, benzylidene bis-(4-hydroxycoumarin) derivatives were used as a curing agent to prepare epoxy resin with high performance and excellent thermal stability. For this purpose,4- benzylidene bis 4-hydroxycoumarin derivatives were synthesized using 2-aminophenol/phoenix dactylifera polymer nanocomposite catalyst. Scanning Electron Microscope (SEM) technique was used to investigate the morphology of cured epoxy resin. The comparison of parameters of degradation start temperature, residual carbon yield and kinetic parameters was done to evaluate the thermal stability of cured epoxy resin using thermogravimetric analysis (TGA). The results showed that the epoxy resin cured with 3,'3-(4-nitrobenzylidene)bis(4-hydroxy-coumarin) have a high degradation start temperature and good carbon efficiency rather than other derivatives. After the 4-nitro derivative, the 4-chloro, 4-fluoro and 4-methyl derivatives have higher thermal stability. So it can be said that the nitro group has provided higher thermal stability rather than chloro, fluoro and methyl groups for cured epoxy resin. As a result, benzylidene 4-hydroxycoumarin derivatives bring high thermal stability to cured epoxy resin due to having aromatic rings

Metallic nanostructures have received a lot of attention. Rapid synthesis using microwaves is a suitable technology that has great potential for use in industrial fields due to the significant reduction in reaction time, increase in product yield, and the use of safe heating sources. The heating method with the help of microwaves has attracted a lot of attention as a suitable method for the synthesis of metal nanostructures in the solution phase. This method has been used to synthesize many nanostructures such as Ag, Au, Pt, Pd and Au-Pd. Not only spherical nanoparticles, but plate, rod, wire, tube and dendritic nanostructures are prepared in a few minutes. Generally, nanostructures with smaller size, narrower size distribution and higher degree of crystallinity are prepared method compared to conventional oil bath heating methods. On the other hand, room temperature ionic liquids (RTILs) have attracted much attention in recent years. ILs can absorb microwaves and increase the reaction speed and decrease the reaction time. The large cations with high polarizability in ILs make these materials suitable solvents for absorbing microwaves. Therefore, the use of microwaves as a heat source along with ILs as a catalyst, solvent, additive, co-solvent and template leads to the creation of a fast and environmentally friendly method (MAIL) for the synthesis of various nanostructures.

Total antioxidant capacity (TAC) as the cumulative activity of antioxidants in a sample is an important parameter in the analysis of biological or food matrices. Therefore, it is very important to evaluate the total antioxidant capacity of the substances in the diet and biological fluids. Based on this, many methods check their antioxidant capacity and effectiveness in different conditions. However, there is often no strong correlation between the capacities measured on the same materials with different methods, which is due to the variety of active materials, mechanisms and different characteristics such as different types of antioxidants, the presence of other interfering substances in the sample, lack of participation of antioxidants are used in the method reaction. In recent years, different analytical methods based on nanoparticles have been developed to determine the antioxidant capacity of foods and plant materials.In these measurement methods, nanoparticles such as gold, silver, iron oxide, manganese oxide, quantum dots and cerium oxide have been used. In this article, we review some of the researches conducted in the field of total antioxidant capacity measurement.

Metal 3D printing is a layer-by-layer fabrication method used to manufacture 3D models of complex structures. This technology has multiple methods, materials, and equipment that bypassing many of the costs associated with traditional processes, equipment, and skills for metal working, while creating free-form, near-net-shape 3D objects. This procedure is more accurately portrayed as additive manufacturing. Additive manufacturing’s attributes include print customization, low perunit cost for production, seamless interfacing with mainstream medical 3D imaging techniques, and feasibility to create freeform objects in materials that are biocompatible and biodegradable. The term 3D printing, in any case, is generally new and has been an active part of current developments in biomedical. Consequently, additive manufacturing is apposite for a wide range of biomedical applications including custom biocompatible implants that mimic the mechanical response of bone, biodegradable scaffolds with engineered degradation rate, medical surgical tools and biomedical instrumentation. This review surveys the materials, 3D printing methods and technologies, and biomedical applications of metal 3D printing.

Metal-organic frameworks (MOFS), which are known as porous coordination polymers, have attracted the attention of countless researchers in recent years. These structures are a new class of porous materials, which are formed by connecting metal ions or clusters with polydentate organic ligands by covalent bonds. Compared to other porous compounds such as zeolites, silica, and activated carbon, coordination polymers are considered multifunctional materials with different properties due to the ability to adjust the surface of the cavity, size, shape, and functional groups of the surface of their cavities. For this reason, these compounds are used in different fields, including gas storage and absorption, manufacturing of various sensors, material separation, medical, biological, environmental and catalysis applications.

Development of the recombinant vaccines against infectious diseases is dependent on the identification of immunogenic antigens and vaccine delivery systems such as polymeric nanoparticles that are able to stimulate immune responses similar to or better than conventional vaccines and reduce complications associated with traditional vaccines. At the present study, synthesis and properties of the sodium alginate nanoparticles carrying CRM197 protein as an antigen delivery system were evaluated. Synthesis of the blank optimized without protein loading and protein-containing nanoparticles was performed by ionic gelation method. After designing of the experiment (DoE) and determining the influential physicochemical factors in ideal nanoparticles synthesis; size, zeta potential, morphology, encapsulation efficiency, release pattern and FT-IR spectroscopy were investigated. The optimized nanoparticles were prepared at a concentration of 0.2% w/v sodium alginate, 0.1% w/v calcium chloride, 0.04% w/v poly-L-lysine during 45 minutes of stirring at 2000 rpm and in pH 6.5. The average nanoparticle size for blank and CRM197 loaded nanoparticles were 88 and 245 nm also zeta potential -21 and -24.2 mV, respectively. LE and LC were >80% and >20%, respectively, associated with a stable and long-term encapsulated protein release pattern from nanoparticles. Absence of local and systemic signs, as well as weight gain in the mice group studied, indicated the safety of the nanoparticles and CRM197 protein combination. Based upon the above achievements, alginate nanoparticles can be used as an antigen delivery system for targeted delivery with controlled, slow release and improved stability of recombinant diphtheria antigen (CRM197) for immunization against diphtheria disease.