Choline chloride – Urea deep eutectic solvent an efficient media for the preparation of metal nanoparticles

Metal nanoparticles are nanosized structures that have different potential applications in biological, chemical, medical, and agricultural fields because of their exotic characteristics. Their size ranges from 1 to 100 nm. Metal nanoparticles are either purer forms of metals (eg: Gold, Silver, Copper, Iron, etc.) or their compounds (eg: sulfides, hydroxides, oxides, etc.). Ionic liquids are generally used in the extraction of nanoparticles but they are challenging because of their indigent bio-degradability, bio-compatibility, and sustainability. So Deep Eutectic Solvent (DES) is reported as an alternative to ionic liquids in the formation of nanoparticles. The DESs are a complex of quaternary ammonium salts and hydrogen donors or metal salt. DESs contain higher non-symmetric ions which have lower lattice energy and hence they have a lower melting point. This research utilizes a novel DES (choline chloride – urea) as an effective solvent to produce mercuric sulfide (HgS), zirconium oxide (ZrO), manganese oxide (MnO), and copper oxide (CuO) nanoparticles. As a result, the production of these metal nanoparticles using Choline Chloride (C₅H₁₄ClNO) – Urea DES can be treated as a promising way in chemical manufacturing. The nanoparticles have been analyzed using Ultra Violet Spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Energy Dispersive X-Ray Analysis (EDAX).     

Strategies of tailored nanomaterials for electrochemiluminescence signal enhancements

Nanomaterials and their applications were studied extensively over the past few decades due to their properties which are associated mainly with the nanoscale sizes and unique characteristics that they have. Among many applications, these nanomaterials have been playing great, multifaceted roles in increasing the analytical performances of electrochemiluminescence (ECL). In this article, we review the main possible approaches – based on nanoparticles – to modify the photophysical properties of the excited state generated as a consequence of the electrochemical stimulus and in particular taking profit of the so-called metal-enhanced fluorescence (MEF) and resonance energy transfer (RET) processes. We believe that these strategies will lead to the design of very efficient systems that can substantially increase the possible successful applications of ECL.     

Recent progress in MXene and graphene based nanocomposites for microwave absorption and electromagnetic interference shielding

There is widespread use of telecommunication and microwave technology in modern society, and raised the electromagnetic interference (EMI) issue to alarming situation due to apprehensive demand and growth of 5G technology undesirably disturbing the human health. The two dimensional (2D) materials including graphene and MXenes are already been used for variety of electronic devices due to their exceptional electrical, mechanical, optical, chemical, and thermal properties. MXene is composed of metal carbides, in which mainly metals are the building blocks for dielectrics, semiconductors, or semimetals. However, the strong interfaces with electromagnetic waves (EM) are variable from terahertz (THz) to gigahertz (GHz) frequency levels and are widely used in EMI and Microwave absorption (MA) for mobile networks and communication technologies. The use of different organic materials with metal, organic, inorganic fillers, polymers nanocomposite and MXene as a novel material has been studied to address the recent advancement and challenges in the microwave absorption mechanism of 2D materials and their nanocomposites. In this concern, various techniques and materials has been reported for the improvement of shielding effectiveness (SE), and theoretical aspects of EMI shielding performance, as well stability of 2D materials particularly MXene, graphene and its nanocomposites. Consequently, various materials including polymers, conducting polymers, and metal–organic frameworks (MOF) have also been discussed by introducing various strategies for improved MA and control of EMI shieling. Here in this comprehensive review, we summarized the recent developments on material synthesis and fabrication of MXene based nanocomposites for EMI shielding and MA. This research work is a comprehensive review majorly focuses on the fundamentals of EMI/MA.  The recent developments and challenges of the MXene and graphene based various structures with different polymeric composites are described in a broader perspective.     

Bio and soft-imprinting lithography on bacterial cellulose films

Bacterial cellulose (BC) is a biocompatible polysaccharide produced by bacteria currently used in packaging, cosmetics, or health care. A highly attractive feature of BC is the possibility of patterning the BC pellicle during its biosynthesis, a concept coined as bio-lithography. BC-patterned films have demonstrated improved properties for cellular-guided growth, implant protection, or wound dressing. However, aspects such as the diversity and size of the features patterned, how those features withstand postprocessing steps, or if large areas can be patterned remain unanswered. Gathering knowledge on these characteristics could extend the use of patterned cellulose-based materials in emerging fields such as transient devices, nanogenerators, or microfluidics. Here, we show that bio-lithographed BC films present good-quality micropatterned features for various motifs (wells, pillars, and channels) in a wide range of sizes (from 200 to 5 μm) and areas as large as 70 cm². Besides, we have studied the fidelity of the motifs and the fiber organization for wet, supercritical, and oven-dried films. When wells and pillars were patterned, the x and y dimensions were faithfully replicated in the wet and dried samples, but only wet and supercritically dried films afforded mold accuracy in the z-direction. In addition, x/z ratio should be carefully considered for obtaining self-standing pillars. Finally, we compared bio-lithography and soft-imprint lithography. In the latter case, fiber alignment was not observed and the depth of the resulting features dramatically decreased; however, this technique allowed us to produce submicron features that remain after the rewetting of the BC films.     

Effect of potassium permanganate on morphological,structural and electro-optical properties of graphene oxide thin films

This work investigated the effect of Potassium Permanganate (KMnO₄) on graphene oxide (GO) properties, especially on electrical properties. The GO thin films were deposited on a glass substrate using drop casting technique and were analysed by using various type of spectroscopy (e.g. Scanning Electron Microscopy (SEM), Ultra- Violet Visible (UV–VIS), Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD), optical band gap, Raman Spectroscopy). Furthermore, the electrical experiments were carried out by using current–voltage (I-V) characteristic. The GO thin film with 4.5 g of KMnO₄ resulted in higher conductivity which is 3.11 × 10^?4 S/cm while GO with 2.5 g and 3.5 g of KMnO₄ achieve 2.47 × 10^?9 S/cm and 1.07 × 10^?7 S/cm, respectively. This further affects the morphological (SEM), optical (band gap, UV–Vis, FTIR, and Raman), and crystalline structural (XRD) properties of the GO thin films. The morphological, elemental, optical, and structural data confirmed that the properties of GO is affected by different amount of KMnO₄ oxidizing agent, which revealed that GO can potentially be implemented for electrical and electronic devices.     

Colloidal chemistry as a guide to design intended dispersions of carbon nanomaterials

In this review, some established concepts from Colloidal Science and their application to graphene and carbon nanotubes dispersions in organic or aqueous media are highlighted to rationalize alternatives for some issues in terms of colloidal properties. Recent applications for carbon-based dispersions are presented, as well as van der Waals interactions in carbon materials and strategies to overcome these interactions, such as increasing electrostatic repulsion between dispersed particles, surface functionalization, or adsorption of passivation agents such as macromolecules, which are the basis of many dispersion and exfoliation procedures. The demonstration of how knowledge and fine control of colloidal interactions have been used to overcome several limitations, such as the preparation of stable and concentrated dispersions of carbon materials and keeping appreciable electrical conductivity, is presented. It is also showed that the same knowledge can help the development of more environmentally friendly carbon-based colloids as well as the improvement of similar systems as dispersions of two-dimensional materials.     

Progress on phthalocyanine-conjugated Ag and Au nanoparticles: Synthesis,characterization, and photo-physicochemical properties

Phthalocyanine (Pc) complexes are an important class of dyes with numerous (e.g., biological, photophysical, and analytical) applications. Among the methods used to improve the properties of these complexes, one should mention the introduction of different substituents, variation of the central metal ion, ligand exchange, and conjugation to nanomaterials (e.g., carbon-based nanomaterials and metal nanoparticles (NPs)). This work briefly reviews Pc complex conjugation to Ag and Au NPs, highlights the different NP shapes, and discusses the diversity of conjugation approaches. Moreover, the use of UV–Vis spectroscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering and Fourier transform infrared spectroscopy to characterize Pc-NP hybrids is summarized. The effect of conjugation on Pc photo-physicochemical properties (fluorescence, singlet oxygen generation, triplet state formation, and optical limiting behavior) is discussed, and future perspectives for the synthesis and applications of new hybrids are provided.     

Ionic liquid–modified cellulosic hydrogels for loading and sustained release of selenourea: an ensuing inhibition of tyrosinase activity

Cellulose-based hydrogel materials were prepared and modified with tannic acid and l-methionine using ionic liquid as the solvent. The gels were prepared to develop a sustained release medium for selenourea (SeU). The drug delivery characteristics of selenourea-loaded cellulose (CSeU), selenourea-loaded tannic acid-modified cellulose (CTSeU), and selenourea-loaded L-methionine-modified cellulose (CMSeU) were investigated in aqueous media and simulated gastric fluid (SGF) media. This modified gel beads have been characterized using field emission scanning electron microscope, X-ray energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, thermogravimetry–differential thermal analysis and swelling properties and compared with those of the unmodified ones. We also investigated the inhibitory effects of SeU released from these gels on the activity of mushroom tyrosinase. Out of all the gel materials, CTSeU showed maximum SeU release both in water and SGF media. However, tyrosinase inhibitory action in PBS medium was comparable for all the three gel materials.     

Nanoparticles: Properties,applications and toxicities

This review is provided a detailed overview of the synthesis, properties and applications of nanoparticles (NPs) exist in different forms. NPs are tiny materials having size ranges from 1 to 100 nm. They can be classified into different classes based on their properties, shapes or sizes. The different groups include fullerenes, metal NPs, ceramic NPs, and polymeric NPs. NPs possess unique physical and chemical properties due to their high surface area and nanoscale size. Their optical properties are reported to be dependent on the size, which imparts different colors due to absorption in the visible region. Their reactivity, toughness and other properties are also dependent on their unique size, shape and structure. Due to these characteristics, they are suitable candidates for various commercial and domestic applications, which include catalysis, imaging, medical applications, energy-based research, and environmental applications. Heavy metal NPs of lead, mercury and tin are reported to be so rigid and stable that their degradation is not easily achievable, which can lead to many environmental toxicities.     

Enhanced rheological properties and performance of viscoelastic surfactant fluids with embedded nanoparticles

A combination of viscoelastic surfactants with nanoparticles gives a new class of functional self-assembled materials promising for a large variety of applications. Nanoparticles improve the rheological properties of these systems because of the incorporation into the network of entangled wormlike micelles by linking to micellar end-caps, thus leading to elongation or cross-linking of the micelles. The present article reviews recent studies of these hybrid systems. Mechanisms of the interaction of nanoparticles with wormlike surfactant micelles as well as factors favoring the enhancement of rheological properties of viscoelastic surfactants by added nanoparticles are discussed, providing ways for proper design of such systems in the future. It is shown that viscoelastic surfactants modified with nanoparticles display very attractive features for practical applications, in particular, for fracturing fluids in oil recovery.     

Paramagnetic surface active ionic liquids: synthesis,properties, and applications

Paramagnetic surface active ionic liquids (PMSAILs) classify task-specific ionic liquids with magnetic properties by incorporating metal into the cationic or anionic part of the ionic liquid. Paramagnetic ionic liquids had long-chain either in cations or anions and showed excellent surface activity and magnetic properties without any need for the magnetic nanoparticles. These PMSAILs have inherent unique ionic liquid properties and self-assembled into various nano-aggregates such as micelles, vesicles, rod-like micelles, and etc., by modification in the structure of cations or anions. PMSAILs provide stimuli-responsive properties, which is one of the essential aspects of targeted applications. The appropriate functional tunability of anions and cations in PMSAILs leads to various multifaceted chemical and biological applications. A new emerging trend in PMSAIL research is hybridization with flexible materials. This review will mainly deal with the synthesis, characterization, and brief history of PMSAILs and their potential advantages in the various applications in micellar catalysis, purification and separation of biomolecules, compaction and decompaction of DNA, drug delivery, and other biomedical applications.     

Green synthesis of copper oxide nanoparticles CuO NPs from Eucalyptus Globoulus leaf extract: Adsorption and design of experiments

The study is concerned with synthesizing copper oxide nanoparticles with leaf extract Eucalyptus Globoulus. The results of scanning electron microscopy (SEM) and dynamic light scattering (DLS) revealed that the green synthesized copper oxide nanoparticles are spherical and have a mean particle size of 88 nm, with a negative zeta potential of ?16.9 mV. The XRD graph showed the crystalline and monoclinic phases of CuO nanoparticles. The average crystalline size around 85.80 nm was observed by the Debye–Scherrer formula. The adsorption characteristics of the nano-adsorbents were investigated using methyl orange, and the adsorption efficiency at room temperature attained 95 mg/g. Copper oxide nanoparticles (CuO NPs) adsorb methyl orange dye most effectively at pH 4.5 when the dye is applied in quantities of 0.04 g/50 mL. Box–Behnken design (BBD) in response surface methodology (RSM) was used to optimize various process parameters, such as pH solution (X₁: 2 – 11), adsorbing dose (X₂: 0.01 – 0.08 g/L), [MO] dye concentration (X₃: 10 – 80 mg/L). Overall, the adjusted coefficient of determination (R²) value of 0.99 demonstrated that the used model was quite appropriate, and the chosen RSM was effective in optimization the decolorization conditions of MO.     

Biosynthesis of silver and gold nanoparticles using Sargassum horneri extract as catalyst for industrial dye degradation

This study focuses on the green synthesis of silver and gold nanoparticles using the marine algae extract, Sargassum horneri, as well as the degradation of organic dyes using biosynthesized nanoparticles as catalysts. The phytochemicals of the brown algae Sargassum horneri acted as reducing and capping agents for nanoparticle synthesis. Ultraviolet–visible absorption spectroscopy, dynamic light scattering, high-resolution transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray spectroscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy were used to characterize the biosynthesized nanoparticles. The green-synthesized SH-AgNPs and SH-AuNPs exhibited high catalytic activity for degradation of organic dyes, such as methylene blue, rhodamine B, and methyl orange. The reduction reactions of dyes are based on pseudo-first-order kinetics.     

New route for removal of Cu(II) using fabricated nanocomposite based on cationic surfactant/Ag-nanoparticles/silica gel

Generally, the treated wastewater must at least achieve the minimum safety standards for the purpose of the treatment process. The main target of this work is the combination of the features of surfactants, nanoparticles, and silica gel in one system for Cu(II) removal from the aqueous solution. To achieve this goal, the attempt would be made by the fabrication of nanocomposite based on 4-amino-N-tetradecyl pyridinium bromide (C14) coated silver nanoparticles and silica gel. The fabricated nanocomposite (C14-Ag-SG) was characterized using different techniques such as FTIR, XRD, XRF, SEM, and TEM. We examined the adsorption of Cu(II) ions onto the fabricated nanocomposite using batch adsorption. The effect of the contact time, pH of the solution, and mass of the adsorbent on the efficiency of adsorption was evaluated. The adsorption capacity of Cu(II) increased by increasing of the contact time with a neutral pH. The maximum removal of Cu(II) ions (98.57 %) was found using 0.4 g of the (C14-Ag-SG) nanocomposite. The fabricated nanocomposite showed high adsorption efficiency which clarifies the effect of the surfactant compound (C14) and silver nanoparticles in improving the adsorption efficiency. The results in this work suggest that the fabricated nanocomposite has high efficiency in the removal of Cu(II).     

Engineering nanostructures of CuO-based photocatalysts for water treatment: Current progress and future challenges

Nowadays, increasing extortions regarding environmental problems and energy scarcity have stuck the development and endurance of human society. The issue of inorganic and organic pollutants that exist in water from agricultural, domestic, and industrial activities has directed the development of advanced technologies to address the challenges of water scarcity efficiently. To solve this major issue, various scientists and researchers are looking for novel and effective technologies that can efficiently remove pollutants from wastewater. Nanoscale metal oxide materials have been proposed due to their distinctive size, physical and chemical properties along with promising applications. Cupric Oxide (CuO) is one of the most commonly used benchmark photocatalysts in photodegradation owing to the fact that they are cost-effective, non-toxic, and more efficient in absorption across a significant fraction of solar spectrum. In this review, we have summarized synthetic strategies of CuO fabrication, modification methods with applications for water treatment purposes. Moreover, an elaborative discussion on feasible strategies includes; binary and ternary heterojunction formation, Z-scheme based photocatalytic system, incorporation of rare earth/transition metal ions as dopants, and carbonaceous materials serving as a support system. The mechanistic insight inferring photo-induced charge separation and transfer, the functional reactive radical species involved in a photocatalytic reaction, have been successfully featured and examined. Finally, a conclusive remark regarding current studies and unresolved challenges related to CuO are put forth for future perspectives.     

Current advances in electrochemical genosensors for detecting microRNA cancer markers

The electrochemical microRNA sensors are considered efficient, simple, and inexpensive analytical tools for the early diagnosis of cancer biomarkers. To enhance the sensitivity of the electrochemical genosensors toward detection of microRNAs, several amplification strategies based mainly on nanomaterials, enzymes, and oligonucleotides are investigated and discussed. This review highlights the main current achievements regarding the new promising and sensitive strategies for genosensors’ development, thus allowing for miroRNA analysis at the attomolar level.     

Investigation of infill-patterns on mechanical response of 3D printed poly-lactic-acid

This paper presents the effect of infill patterns (IPs) on the mechanical response of 3D printed specimens by conducting the low-velocity impact test (LVI) and compression test. The poly-lactic acid (PLA, purity 98 wt% >) material has selected and printed using fused deposition modeling (FDM, speed 20 mm/s, layer height 0.2 mm, no of layers 30, extruded at 200 °C) with four different IPs: triangle, grid, quarter cubic, and tri-hexagon. The LVI test on velocity-time, energy-time and force-displacement, and the compression responses have examined and presented in this study. The LVI test was carried out to determine the penetration energy level, energy absorption capacity (toughness), stiffness, and strength of PLA porous parts (60% infill density) for implant/tissue/recyclable product applications. The results have shown that the triangular pattern has produced the highest absorbed energy in LVI test (penetration energy 7.5 J, and stiffness 668.82 N/mm) due to more sheared/contact layers’ perpendicular to impactor (hemispherical insert); while the grid pattern exhibited the highest compressive strength (72 MPa) due to more layers aligned along the compressive loading direction The SEM fracture surface image of Triangular IP has produced effective raster and layer bonding, less number of voids, more amount of circular beach markings, and absence of ratchet lines leading to possess improved mechanical properties.     

Synthesis and characterization of copolymers of β-cyclodextrin derivatives

Cyclodextrins (CDs) are cyclic oligosaccharides made up of d-glucose units connected by 1,4-glucosidic linkages. β-CD is a cyclical starch derivative containing seven glucopyranose units. β-CD derivatives have characteristic property of larger surface area, robust mechanical strength, high surface to volume ratio, electrical and optical properties for analyte determination, good dispersion, easy removal of the template, surface modification, functionalization and handling capacity. In this work, an attempt is made to prepare succinyl-β-CD-acrylamide (S-β-CD-AA) copolymer and β-CD-malic anhydride (β-CD-MAH) copolymer. For the synthesis of S-β-CD-AA, S-β-CD derivative is prepared and further, acrylamide (AA) along with cross-linker undergoes free radical copolymerization for the formation of gel like product. The degree of succinylation (DS) of β-CD derivative is estimated. S-β-CD-AA copolymer showed potential swelling, and deswelling characteristic. Another copolymer is prepared from β-CD malic anhydride derivative. Further, the derivative is treated with cellulose and ethylene diamine tetra acetate (EDTA) to form β-CD-MAH copolymer. The two derivatives are characterized by several techniques. Thermal stability of these copolymers is estimated with the help of thermogravimetric analysis. The basic characterization of the presence of functional groups is done using UV–visible spectroscopy, and infrared spectroscopy. The elemental analysis helped to estimate C, H, N, S in the synthesized compounds. The surface morphology characterization is done with the help of scanning electron microscopy. X-ray diffraction analysis helped in determination of crystal structure of β-CD-MAH. β-CD derivatives prepared may be potential candidate to prepare inclusion complex, in drug delivery, drug loading and several similar applications.     

An ultrasensitive electrochemical immunosensor for CA72-4 based on a signal amplification strategy of MoS2 nanoflower-supported Au nanoparticles

Accurate detection of cancer antigen 72-4 (CA72-4), a tumor-associated glycoprotein, is of great significance for gastric cancer diagnosis and immunotherapy monitoring. Modification of noble metal nanoparticles on transition metal dichalcogenides can significantly enhance functions, such as electron transport. Molybdenum disulfide gold nanoparticles nanocomposites (MoS₂-Au NPs) were prepared in this study and a series of characterization studies were carried out. In addition, a label-free, highly sensitive electrochemical immunosensor molybdenum disulfide -Au nanoparticles/Glassy carbon electrode (MoS₂-Au NPs/GCE) was also prepared and used for the detection of CA72-4. The electrochemical performance of the immunosensor was characterized by electrochemical techniques, such as cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The results indicated that better MoS₂-Au NPs nanomaterials have been synthesized, and the prepared electrochemical immunosensor, MoS₂-Au NPs/GCE, showed excellent electrochemical performance. The sensor exhibited high detection sensitivity under optimal conditions, including an incubation time of 30 min, an incubation temperature of 25 °C, and a pH of 7.0. The electrochemical immunosensor also had a low detection limit of 2.0 × 10^?5 U/mL (S/N = 3) in a concentration range of 0.001–200 U/mL, with good selectivity, stability, and repeatability. In conclusion, this study provided a theoretical basis for the highly sensitive detection of tumor markers in clinical biological samples.     

Conjugate polymer-based membranes for gas separation applications: current status and future prospects

Conjugate polymers provide the possibility of exploiting both the chemical and physical attributes of the polymers for membrane-based gas separation. The presence of delocalized π electrons provides high chain stiffness with low packing density, thus making the membrane a rigid structure that favors facilitated transport. Historically, the polymeric membranes were constrained by the tradeoff relationship between gas permeability and gas selectivity. So, different methods were investigated to prepare the membranes that can overcome the limitation. In recent years, electroconductive polymeric membranes have gained attention with their enhanced transportation properties combining the separation behavior depending on both molecular size discrimination as well as the facilitated transport. They offer better selectivity toward polar gases such as CO₂ because of the increased solubility. This review is aimed to provide a literature survey on gas separation using conjugate polymers such as polyaniline, polypyrrole, and some derivatives of polythiophenes. It contains various methods used by different researchers to enhance the gas separation properties of the membranes with improved mechanical and thermal stability such as changing the morphology and membrane preparation methods. In addition, it provides the pros and cons of various factors affecting the conjugate polymer membrane performance. The major challenges and future work that can be done in improving the transportation properties through the membrane to achieve viable membranes are also discussed so that they can be used for commercial and practical applications in the future.