Encapsulation of silver nanocomposites and effects of stabilizers

Utility of Biogenic Iron and Its Bimetallic Nanocomposites for Biomedical Applications: A Review

Nanotechnology mainly deals with the production and application of compounds with dimensions in nanoscale. Given their dimensions, these materials have considerable surface/volume ratios, and hence, specific characteristics. Nowadays, environmentally friendly procedures are being proposed for fabrication of Fe nanoparticles because a large amount of poisonous chemicals and unfavorable conditions are needed to prepare them. This work includes an inclusive overview on the economical and green procedures for the preparation of such nanoparticles (flower, fruits, tea, carbohydrates, and leaves). Pure and bimetallic iron nanoparticles, for instance, offer a high bandwidth and excitation binding energy and are applicable in different areas ranging from antibacterial, anticancer, and bioimaging agents to drug delivery systems. Preparation of nano-sized particles, such as those of Fe, requires the application of high quantities of toxic materials and harsh conditions, and naturally, there is a tendency to develop more facile and even green pathways (Sultana, Journal of Materials Science & Technology, 2013, 29, 795–800; Bushra et al., Journal of hazardous materials, 2014, 264, 481–489; Khan et al., Ind. Eng. Chem. Res., 2015, 54, 76–82). This article tends to provide an overview on the reports describing green and biological methods for the synthesis of Fe nanoparticles. The present review mainly highlights selenium nanoparticles in the biomedical domain. Specifically, this review will present detailed information on drug delivery, bioimaging, antibacterial, and anticancer activity. It will also focus on procedures for their green synthesis methods and properties that make them potential candidates for various biomedical applications. Finally, we provide a detailed future outlook.

Preparation and characterization of redox-sensitive glutenin nanoparticles

In recent thirty years, protein-based nanoparticles have attracted considerable attention, and they are being widely used in the food, pharmaceutical, and biomedical fields. Wheat glutenin, an important natural vegetable protein, has been demonstrated to be nutritive and biocompatible. This study aimed to develop a new type of redox-sensitive protein nanoparticles. The glutenin nanoparticles (GNPs) were synthesized with glutenin concentrations (0.082%, 0.5%, and 0.83%) through the adoption of an antisolvent titration technique and the use of hydrogen peroxide (H₂O₂) oxidative cross-linking for different periods. At a glutenin concentration of 0.83% and oxidation time of 20 h, the obtained GNPs were spherical in shape and approximately 100-300 nm in size, as measured by transmission electron microscopy and dynamic light scattering. The formation of disulfide was confirmed by Raman spectroscopy. The turbidity values of the GNP suspensions were decreased by half after the addition of β-mercaptoethanol. Nile blue A, a model hydrophilic substance, was entrapped in the GNPs with 77.67% loading efficiency. The newly developed GNPs can be used as redox-responsive carriers for delivering hydrophilic active substances.

Reversible encapsulation of silver nanoparticles into the helix of amylose (water soluble starch)

Natural biodegradable polymeric starch capped Ag-nanoparticles (AgNPs) were prepared by using extract of Dioscorea deltoidea in the presence of starch.

Nanoscale water soluble self-assembled zero-valent iron: role of stabilizers in their morphology

Self-assembled water soluble sheet-like zero-valent iron nano-composites were prepared using a simple one-pot chemical reduction method in an aqueous solution of FeCl₃and NaBH₄both with and without CTAB and SDS.

Green synthesis of biogenic silver nanomaterials using Raphanus sativus extract, effects of stabilizers on the morphology, and their antimicrobial activities

The present study explores the reducing and capping potentials of aqueous Raphanus sativus root extract for the synthesis of silver nanomaterials for the first time in the absence and presence of two stabilizers, namely, water-soluble starch and cetyltrimethylammonium bromide (CTAB). The surface properties of silver nanoparticles (AgNPs) were determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), energy dispersion X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) techniques. The mean size of AgNPs, ranging from 3.2 to 6.0 nm, could be facilely controlled by merely varying the initial [extract], [CTAB], [starch], and [Ag(+)] ions. The agglomeration number, average number of silver atoms per nanoparticle, and changes in the fermi potentials were calculated and discussed. The AgNPs were evaluated for their antimicrobial activities against different pathogenic organisms. The inhibition action was due to the structural changes in the protein cell wall.

Biosynthesis of silver nanoparticles and its antibacterial and antifungal activities towards Gram-positive, Gram-negative bacterial strains and different species of Candida fungus

Biomimetic and economic method for the synthesis of silver nanoparticles (AgNPs) with controlled size has been reported in presence of shape-directing cetlytrimethylammonium bromide (CTAB). Biochemical reduction of Ag(+) ions in micellar solution with an aqueous lemon extract produced spherical and polyhedral AgNPs with size ranging from 15 to 30 nm. The influence of [CTAB] and [lemon extract] on the size of particles, fraction of metallic silver and their antimicrobial properties is discussed. The AgNPs were evaluated for their antimicrobial activities (antibacterial and antifungal) against different pathogenic organisms. For this purpose, AgNPs were tested against two model bacteria (Staphylococcus aureus (MTCC3160) and Escherichia coli (MTCC405)) and three species of Candida fungus (Candida albicans (ATCC90028), Candida glabrata (ATCC90030) and Candida tropicalis (ATCC750). AgNPs were found to be highly toxic towards both bacteria. The inhibition action was due to the structural changes in the protein cell wall.

Synthesis, optical properties, stability, and encapsulation of Cu-nanoparticles

Starch-capped copper nanoparticles (CuNPs) were prepared by a chemical reduction method using hydrazine, copper sulfate and starch as reducing, oxidizing and stabilizing agents, respectively, for the first time at room temperature. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction patterns (EDX), X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FT-IR) spectroscopy, thermo-gravimetric analysis (TGA), and ultraviolet-visible spectroscopy. The effect of [starch], [hydrazine] and [copper sulfate] on the optical properties of CuNPs were studied by UV-visible spectrophotometrically. The hydrazine concentrations have large impact on the surface Plasmon resonance absorbance, nature of the reaction time curves and reaction rates decreases with [hydrazine]. Starch concentrations have no effect on the path of the CuNPs formation. The hexahedral with some irregular shaped CuNPs were formed in presence of starch with diameter 900 nm. Starch acted as a stabilizing, shape-directing and capping agent during the growth processes. The KI-I2 reagent could not replace CuNps from the inner helical structure of starch.