Preparation and Characterization of Silver Nanoparticles in Montmorillonite and Gelatin Using Physical and Chemical Methods

Metal nanoparticles in inorganic and organic materials have generated novel materials that display unique optical, catalysis, or biological properties making them attractive for using in various application areas. A big challenge in the synthesis of nanoparticles is particle aggregation or precipitation. This phenomenon can be inhibited with stabilization of nanoparticles by suitable polymers or chemical species as colloidal stabilizers. This thesis describes the different preparation methods and characterization of silver nanoparticles (Ag-NPs) in organic and inorganic materials as well as their potential applications. The methods used consist of green chemical method and physical methods, e.g., UV irradiation, pulsed laser ablation (PLA), and y-irradiation. Silver nitrate, montmorillonite (MMT), gelatin, glucose, NaOH, and silver plate were used as starting materials in this work. In UV irradiation method, Ag-NPs were prepared at different irradiation times (i.e., 1, 3, 18, 48, and 96 hr) in MMT and gelatin (i.e., 1, 3, 6, 18, 24, and 48 hr) as inorganic and organic matrix, respectively. UV-vis spectra and transmission electron microscopy (TEM) images demonstrate the particles size of Ag-NPs decrease with the increase of UV irradiation time. In y-irradiation method, when the irradiation dose was increased (from 5 to 50 kGy); the mean size of particles reduced continuously (from 20.4 to 16.4 nm) due to the y-induced Ag-NPs fragmentation. In PLA technique it was found smaller particle size distributions of Ag-NPs were obtained with smaller repetition rates and longer laser ablation times. Also, the UV-vis and TEM images demonstrated that the mean diameter of Ag-NPs increased (from 8.9 to 14.7 nm) as the laser repetition rate was increased (from 10 to 40 Hz). The use of inexpensive chemicals and non-toxic solvents – environmentally friendly and renewable/biodegradable – are central to materials synthesis. The green chemistry rules were applied for preparation of Ag-NPs in gelatin using glucose as a reducing agent,where the particle diameters of Ag-NPs at different temperatures and reaction times were investigated. It was found that with increasing of reaction times (from 6 to 48 hr) the size of Ag-NPs decreased (from 9.6 to 5.3 nm). The particle size of Ag-NPs obtained in gelatin solutions (3.7 nm) is smaller than in gelatin-glucose solutions (5.3 nm) which can be related to rate of reduction reaction. The stability of prepared Ag-NPs, as shown by UV-vis spectral analysis, was significant. The obtained Ag-NPs were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). In addition, the Ag-NPs prepared in this work may have value for the creation of antibacterial and antimicrobial paints and coatings for household materials, surgical and food storage equipments

Synthesis and characterization of a narrow size distribution of zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnO-NPs) were synthesized via a solvothermal method in triethanolamine (TEA) media. TEA was utilized as a polymer agent to terminate the growth of ZnO-NPs. The ZnO-NPs were characterized by a number of techniques, including X-ray diffraction analysis, transition electron microscopy, and field emission electron microscopy. The ZnO-NPs prepared by the solvothermal process at 150°C for 18 hours exhibited a hexagonal (wurtzite) structure, with a crystalline size of 33 ± 2 nm, and particle size of 48 ± 7 nm. The results confirm that TEA is a suitable polymer agent to prepare homogenous ZnO-NPs

Antimicrobial Activity of Colloidal Selenium Nanoparticles in Chitosan Solution against Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans

Objective: To investigate the antimicrobial activity of colloidal selenium nanoparticles in chitosan solution (Cts-Se-NPs) against Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans. Material and Methods: Cts-Se-NPs solution was prepared using a simple chemical reduction method. The MIC and MBC against S. mutans, L. acidophilus, and C. albicans were determined using the broth dilution assay. Results: The Cts-Se-NPs had remarkable antimicrobial activity against S. mutans, L. acidophilus, and C. albicans. The MIC values of the Cts-Se-NPs were lowest for S. mutans (0.068 mg/ml) compared to L. acidophilus (0.137 mg/ml), and C. albicans (0.274 mg/ml). The MBC values of the Cts-Se-NPs against the microorganisms after one, two, six, and 24 hours indicated that the concentration of 0.274 mg/ml of Cts-Se-NPs completely killed S. mutans, L. acidophilus, and C. albicans after one, two, and six hours, respectively. At the concentration of 0.137 mg/ml, S. mutans and L. acidophilus were killed after six and 24 hours, respectively. Conclusion: These findings encourage the potential use of Cts-Se-NPs in dentistry, while further clinical research is required in this area

Two-dimensional-Ti3C2 magnetic nanocomposite for targeted cancer chemotherapy

Introduction: Cervical cancer is the leading cause of cancer-related death in women, so novel therapeutic approaches are needed to improve the effectiveness of current therapies or extend their activity. In recent decades, graphene analogs, such as Mxene, an emerging class of two-dimensional (2D) graphene analogs, have been drawing considerable attention based on their intrinsic physicochemical properties and performance as potential candidates for tumor therapy, particularly for therapeutic purposes. Here we explored the targeted drug delivery in cervical cancer in in vivo model. Mxene-based nanocarriers are not able to be precisely controlled in cancer treatment.Method: To solve this problem, the titanium carbide-magnetic core-shell nanocarrier (Ti3C2-Fe3O4@SiO2-FA) is also developed to provide synergetic anticancer with magnetic controlling ability along with pH-responsive drug release. A xenograft model of the cervix was used to investigate the effects of Cisplatin alone, or in combination with Ti3C2@FA and Ti3C2@ Fe3O4@SiO2-FA, on tumor growth following histological staining for evaluation of necrosis.Result and Discussion: A significant tumor-growth suppression effect is shown when the Ti3C2-Fe3O4@SiO2-FA nanocarrier is magnetically controlled Cisplatin drug release. It reveals a synergistic therapeutic efficacy used in conjunction with pharmaceuticals (p < .001). According to the in vivo study, the Ti3C2@FA@Cisplatin nanocomposite exhibits less tumor growth than the drug alone or Ti3C2@FA@Cisplatin via increasing necrosis effect (p < .001). Through this study, Mxene nanosheets are expanded for biomedical applications, not only through the fabrication of biocompatible magnetic Mxene nanocomposite but also through the development of functionalization strategies that enable the magnetic Ti3C2 nanocomposite to load high levels of Cisplatin for cervical cancer treatment (242.5%). Hence, Ti3C2-Fe3O4@SiO2-FA nanocarriers would be promising candidates to improve cancer treatment efficiency

Cerium oxide nanoparticles: green synthesis and biological applications

CeO2 nanoparticles (NPs) have shown promising approaches as therapeutic agents in biology and medical sciences. The physicochemical properties of CeO2-NPs, such as size, agglomeration status in liquid, and surface charge, play important roles in the ultimate interactions of the NP with target cells. Recently, CeO2-NPs have been synthesized through several bio-directed methods applying natural and organic matrices as stabilizing agents in order to prepare biocompatible CeO2-NPs, thereby solving the challenges regarding safety, and providing the appropriate situation for their effective use in biomedicine. This review discusses the different green strategies for CeO2-NPs synthesis, their advantages and challenges that are to be overcome. In addition, this review focuses on recent progress in the potential application of CeO2-NPs in biological and medical fields. Exploiting biocompatible CeO2-NPs may improve outcomes profoundly with the promise of effective neurodegenerative therapy and multiple applications in nanobiotechnology

Laser-fabricated castor oil-capped silver nanoparticles

Silver nanoparticles were fabricated by ablation of a pure silver plate immersed in castor oil. A Nd:YAG-pulsed Q-switch laser with 1064-nm wavelength and 10-Hz frequency was used to ablate the plate for 10 minutes. The sample was characterized by ultraviolet-visible, atomic absorption, Fourier transform-infrared spectroscopies, and transmission electron microscopy. The results of the fabricated sample showed that the nanoparticles in castor oil were about 5-nm in diameter, well dispersed, and showed stability for a long period of time

Antioxidant and toxicity studies of biosynthesized cerium oxide nanoparticles in rats

Funding Information: We would like to thank the Vice Chancellery for Research and Technology, MUMS for financial support (grant no 930954) and facilities.Peer reviewedPublisher PD

Synthesis and characterization of silver/talc nanocomposites using the wet chemical reduction method

In this study, silver nanoparticles (Ag-NPs) were synthesized using the wet chemical reduction method on the external surface layer of talc mineral as a solid support. Silver nitrate and sodium borohydride were used as the silver precursor and reducing agent in talc. The talc was suspended in aqueous AgNO3 solution. After the absorption of Ag+ on the surface, the ions were reduced with NaBH4. The interlamellar space limits were without many changes (ds = 9.34–9.19 Aº); therefore, Ag-NPs formed on the exterior surface of talc, with dave = 7.60–13.11 nm in diameter. The properties of Ag/talc nanocomposites (Ag/talc-NCs) and the diameters of the Ag-NPs prepared in this way depended on the primary AgNO3 concentration. The prepared Ag-NPs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared. These Ag/talc-NCs may have potential applications in the chemical and biological industries

Green synthesis and characterization of gelatin-based and sugar-reduced silver nanoparticles

Silver nanoparticles (Ag-NPs) have been successfully prepared with simple and “green” synthesis method by reducing Ag+ ions in aqueous gelatin media with and in the absence of glucose as a reducing agent. In this study, gelatin was used for the first time as a reducing and stabilizing agent. The effect of temperature on particle size of Ag-NPs was also studied. It was found that with increasing temperature the size of nanoparticles is decreased. It was found that the particle size of Ag-NPs obtained in gelatin solutions is smaller than in gelatin–glucose solutions, which can be related to the rate of reduction reaction. X-ray diffraction, ultraviolet-visible spectra, transmission electron microscopy, and atomic force microscopy revealed the formation of monodispersed Ag-NPs with a narrow particle size distribution