An ultrasonic method for the synthesis, control and optimization of CdS/TiO2 core–shell nanocomposites

A review on green approaches utilizing phytochemicals in the synthesis of vanadium nano particles and their applications

In the modern era, inorganic nanoparticles have received profound attention as they possess boundless applications in various fields. Among these, vanadium-based nanoparticles (VNPs) are highly remarkable due to their inherent physiological and biological properties with many therapeutic and other applications, such as drug delivery systems for diseases like cancer, environmental remediation, energy storage, energy conversion, and photocatalysis. Moreover, physically, and chemically synthesized VNPs are very versatile, however, these synthesis routes cause concern to health and the environment due to the highly savage reaction conditions, using highly toxic and harsh chemicals, which compel the researchers to develop an eco-friendly, greener, and sustainable route for synthesis. In this outlook, to avoid the innumerable limitations, a bio approach is used over chemical and physical methods. This present review emphasis on the role of various biological components in the synthesis, especially Phyto-molecules that acts as capping and reducing agent, and solvent system for the nanoparticles synthesis. Furthermore, the influence of various factors on the biogenic synthesized nanoparticles has also been discussed. Finally, potential applications of as-synthesized VNPs, principally as an antimicrobial agent and their role as a nanomedicine, energy applications as a supercapacitor, and photocatalytic agents, have been discussed.

Nano cerium oxide and cerium/zinc nanocomposites characterization and therapeutic role in combating obesity via controlling oxidative stress and insulin resistance in rat model

BACKGROUND

CeO2NPs and ZnONPs can curb the increase of cholesterol and triglycerides observed in rats with non-alcoholic fatty liver disease. It was suggested that CeO2 NPs could potentially have an insulin-sensitizing effect, specifically on adipose tissue and skeletal muscle. It was reported that ZnONPs combat the increase of insulin resistance observed in obese rats and could be beneficial value in NAFLD. In our previous work, ZnO-NPs manifested valuable anti-obesity effects via lowering body weight gain, oxidative stress, BMI, lipids, and insulin resistance.

METHODS

In the present study, cerium oxide nanoparticles (A-1) and cerium/zinc nanocomposites (A-2 and A-3) were synthesized by solgel to investigate their role on oxidative stress, adipocyte hormones, and insulin resistance in an obese rat model. X-ray diffraction, HRTEM, SEM, and XPS were carried out to confirm the crystal structure, the particle size, the morphology of the nanoparticles and the oxidation states.

RESULTS

The Rietveld refinement has also been executed on A-1 (chi2 = 1.00; average Bragg = 2.92%; R-factor = 2.45%) and on A-2 (Rw = 9.87%, Rex= 9.68%, χ2 = 1.04, GoF = 1.02). The XPS spectra indicated the presence of Ce in + 4 and + 3 oxidation states and Zn as ZnO and ZnO.OH. Cerium oxide and ZnO crystal sizes lie in the range 40.53-45.01 and 40.53-45.01 nm, respectively. The results indicated that treating obese rats with any of the tested nano compounds (5 mg or 10 mg/Kg) lowered plasma cholesterol, triglycerides, LDL, insulin resistance, glucose, and BMI significantly relative to obese group values. On the other hand, HDL increased significantly in obese rats after treatment with either A-2 or A-3 compared to obese rats. The current investigation showed antioxidant activities for A-1, A-2, and A3 as evidenced by the significant increase in GSH level and a significant decrease in MDA.

CONCLUSION

It was found that A-1, A-2, and A-3 have an efficient therapeutic role in treating of obesity-related hyperlipidemia, oxidative stress and insulin resistance. The results of A-2 and A-3 were more pronounced than those of A-1. The use of Zn/Ce nanocomposite (that have positive characteristics) in combating obesity and its complications could be become a new trend in therapeutic application for a management of obesity.

Formation of inorganic liquid gallium particle-manganese oxide composites

Gallium (Ga) is a low melting point post-transition metal that, under mild mechanical agitation, can form micron and submicron-sized particles with combined fluid-like and metallic properties. In this work, an inorganic network of Ga liquid metal particles was synthesised via spontaneous formation of manganese (Mn) oxide species on their liquid metallic surfaces forming an all-inorganic composite. The micron-sized Ga particles formed by sonication were connected together by Mn oxide nanostructures spontaneously established from the reduction of a Mn salt in aqueous solution slightly above the melting point of Ga. The formed Mn oxide nanostructures were found to coalesce from the surface of the Ga particles into a continuous inorganic network. The morphology of the composites could be altered by varying the Mn salt concentration and by performing post-treatment annealing. The composites presented a shell of various Mn oxide nanostructures including wrinkled sheets, rods and nanoneedles, around spherical liquid Ga particles, and a liquid metal core. The photoelectric and optical properties of the composites were thoroughly characterised, which revealed decreasing bandgaps and valence band edge characteristics as a function of increased Mn oxide coverage. The photoluminescence properties of the composites could be also engineered by increasing the Mn oxide coverage. The all-inorganic liquid Ga composite could be formed via a straightforward reduction reaction of a Mn-rich salt at the surface of liquid Ga particles with tunable surface properties for future optoelectronic applications.

Soft Bioelectronics Based on Nanomaterials

Recent advances in nanostructured materials and unconventional device designs have transformed the bioelectronics from a rigid and bulky form into a soft and ultrathin form and brought enormous advantages to the bioelectronics. For example, mechanical deformability of the soft bioelectronics and thus its conformal contact onto soft curved organs such as brain, heart, and skin have allowed researchers to measure high-quality biosignals, deliver real-time feedback treatments, and lower long-term side-effects in vivo. Here, we review various materials, fabrication methods, and device strategies for flexible and stretchable electronics, especially focusing on soft biointegrated electronics using nanomaterials and their composites. First, we summarize top-down material processing and bottom-up synthesis methods of various nanomaterials. Next, we discuss state-of-the-art technologies for intrinsically stretchable nanocomposites composed of nanostructured materials incorporated in elastomers or hydrogels. We also briefly discuss unconventional device design strategies for soft bioelectronics. Then individual device components for soft bioelectronics, such as biosensing, data storage, display, therapeutic stimulation, and power supply devices, are introduced. Afterward, representative application examples of the soft bioelectronics are described. A brief summary with a discussion on remaining challenges concludes the review.

Effective Strategies, Mechanisms, and Photocatalytic Efficiency of Semiconductor Nanomaterials Incorporating rGO for Environmental Contaminant Degradation

The water pollution problems severely affect the natural water resources due to the large disposal of dyes, heavy metals, antibiotics, and pesticides. Advanced oxidation processes (AOP) have been developed using semiconductor nanomaterials as photocatalysts for water treatment as an essential strategy to minimize environmental pollution. Significant research efforts have been dedicated over the past few years to enhancing the photocatalytic efficiencies of semiconductor nanomaterials. Graphene-based composites created by integrating reduced graphene oxide (rGO) into various semiconductor nanomaterials enable the unique characteristics of graphene, such as the extended range of light absorption, the separation of charges, and the high capacity of adsorption of pollutants. Therefore, rGO-based composites improve the overall visible-light photocatalytic efficiency and lead to a new pathway for high-performance photocatalysts’ potential applications. This brief review illustrates the strategies of combining rGO with various semiconductor nanomaterials and focuses primarily on modification and efficiency towards environmental contaminants.

The degradation of cellulose in ionic mixture solutions under the high pressure of carbon dioxide

This work aims to study the product characteristics of cellulose degradation not only by a hydrothermal process but also in combination with a sonication process. Herein, 4.3 mL of oxalic acid (H2C2O4)-sodium chloride (NaCl) solution containing cellulose was placed into a stainless steel reactor (or the mixture was placed into the reactor after the sonication process for 1 hour); then, carbon dioxide (CO2) was released for pressurization. Degradation was performed under certain pressures (70 and 200 bar) and temperatures (125 °C and 200 °C) at various times. Scanning Electron Microscopy (SEM) results indicated that the sonication pretreatment process affected the solid cellulose, making it rougher or fibrous than the non-sonicated process. XRD characterization results indicated that both process types caused changes in the crystallinity and composition of cellulose I and II with pressure, temperature, and time. The combination of sonication and hydrothermal processes resulted in lower crystallinity. Changes in crystallinity showed different characteristics in swelling, reduced the interaction between chains, and even broke the polymer chains inside the particles. In a hydrothermal process at 200 bar and 200 °C, a maximum reducing sugar concentration of 5.1 g L-1 was obtained, while 3.2 g L-1 was obtained in the combined sonication and hydrothermal process under the same operating condition, which is below the value attained at 200 °C and 70 bar. These results indicated the existing competition between the formation and further degradation of the reducing sugar, a phenomenon explained by the presence of a monomer (reducing sugar), an oligomer (cellotriose), and 5-HMF (5-hydroxymethyl-2-furaldehyde) in a liquid product processed under hydrothermal conditions.

Sonochemical catalysis as a unique strategy for the fabrication of nano-/micro-structured inorganics

Ultrasound-assisted approaches, as an important trend in material synthesis, have emerged for designing and creating nano-/micro-structures. This review simply presents the basic principles of ultrasound irradiation including acoustic cavitation, sonochemical effects, physical and/or mechanical effects, and on the basis of the latest progress, it newly summarizes sonochemical catalysis for the fabrication of nano-structured or micro-structured inorganic materials such as metals, alloys, metal compounds, non-metal materials, and inorganic composites, where the theories or mechanisms of catalytic synthetic routes, and the morphologies, structures, sizes, properties and applications of products are described in detail. In the review, a few technological potentials and probable challenges of sonochemical catalysis are also highlighted for the future advance of synthesis methods. Therefore, sonochemical catalysis or ultrasound-assisted synthesis will serve as a unique strategy to reveal its great significance in material fabrication.

Review on Polymeric Citrate Precursor and Sono-chemical Methods for the Synthesis of Nanomaterials

Background:

he properties of materials depend on the way of construction and the arrangement of atoms and molecules. Therefore, it is very important to know synthesis methods for the preparation of novel materials as per their desired structure. The low-temperature synthesis methods, such as polymeric citrate precursor and sonochemical methods are efficient enough to control the preparation of novel nanoparticles with morphological differences that leads to the novel devices with desired technological performances. These methods are simple, very less expensive and are easy to handle to operate for the synthesis of nanoparticles as per the expected morphology and dimensions.

Methods:

Polymeric citrate precursor method, a chelate-based method involves the reaction between mixed cations with citric acid, and then these cations are cross-linked with the help of ethylene glycol for the esterification process. Gel composites were heated which burns the organic moieties leaving behind the nanoparticles, and burning gels becomes essential for the reduction of nanoparticles. The sonochemical method, on the other hand, uses ultrasonic the irradiation results. The acoustic cavitation and high intensity ultrasound has been exploited for the preparation of different series of nanoparticles.

Results:

Commonly known for polymeric citrate method as Pechini gel pyrolysis method gives the evidence of versatile and elegant method for the synthesis of nanoparticles. The sonochemical method provides an unusual route of nanoparticle fabrication without bulk and that too with low temperature and pressure or less reaction time. These two methods have better control for the desired shape morphology and size and provide many opportunities for the use of these prepared nanoparticles in various aspects of science and technology.

Conclusion:

Polymeric citrate precursor and sonochemical methods are efficient to reduce to promote desirable reaction conditions and reduce the metal ions for the fabrication of nanoparticles. The prepared nanoparticles by using such low-cost elegant methods are uniform with a small size distribution, reproducible with good yield as per the demanded applications.