Abstract: Transition metal vanadates (MxVyOz, M = Co, Zn, Ni, Cu, Fe), also called binary metal oxides, are one of the members of the mixed metal oxide (AxByOz) family. This kind of material has become a subject of great interest in being active electrode materials in the area of pseudo-supercapacitors these years due to their multiple oxidation states, layered structure, and the synergistic effect between transition metal and vanadium. Furthermore, nanostructured transition metal vanadates can provide a high specific surface area and sufficient electroactive sites and shorten the ion diffusion pathway. With these benefits, electrochemical performance in pseudo-supercapacitors can be significantly improved. In this review, the recent progress of various nanostructures of transition metal vanadates was focused on. The detailed literatures mainly included three typical types, namely cobalt vanadates, zinc vanadates, and nickel vanadates. Moreover, some key concerns on these materials were illustrated, including fabrication approaches, morphology structures, and electrochemical performance. In addition, two typical designed strategies to obtain various transition metal vanadates with good specific capacitance and high cyclic performance were summarized. One was the design and preparation of various nanostructures with different dimensions from 0 dimension (0D) to 3 dimension (3D). The other was the hybridization of metal vanadates with carbonaceous material, metal oxide, and some other chemical components. At last, possible thoughts of promoting future breakthroughs in this field were provided.

Abstract: The surface–chemically modified superparamagnetic iron oxide nanoparticles are broadly investigated as magnetic resonance imaging contrast agents based on their unique characteristics such as high magnetization values, diameter from 4 to 100 nm, and narrow distribution of particle size. However, naked nanoparticles might be easily oxidized by the air leading to loss of dispersibility and magnetization. Therefore, suitable surface coating strategies were developed to increase the stability of magnetic iron oxide contrast agents in the physiological conditions. In addition, the polymer-coated agents possess an improved biocompatibility in comparison with conventional agents. This review discusses important aspects of newly developed magnetic contrast agents such as chemical synthesis strategies, physical parameters, relaxivity parameters, the effect of various coatings, and emerging applications. Disadvantages associated with commercially available gadolinium contrast agents are considered, and the advantages of potential applications of iron oxide alternatives to traditional agents are presented. Finally, perspectives of the future developments, applications, and concerns of the magnetic nanoparticles are also included.

Abstract: The most suitable strategy to improving the long-term viability of cancer patients and overcoming the high morbidity and severity of cancer is the precise identification of particular tumor markers related to cancer using non-invasive techniques. A suitable and immediate therapeutic action may result in the measurement of biomarkers at various phases of cancer. In this scope, the detection of biomarkers by various nanosensors is at the forefront of innovation into cancer diagnosis due to their specific features such as flexibility, rapid response, precise measurement, and multipathing and miniaturization processability. In this review, different nanobiosensors and several biomarkers were discussed for diagnosis of colorectal cancer. In the last few years, multifunctional nanostructured materials have shown a considerable potential to augment the efficacy, selectivity, specificity, and controlled release of various drugs for colorectal cancer treatment. Nanotechnology-based drug delivery systems hold enormous perspective to minimize systemic toxicity by the construction of modified nanomaterials for target-specific treatment. This review shed light on the current progress of various kinds of nanomaterials such as dendrimers, liposomes, micelles, lipid nanodiscs, nano-cubosomes, and nanoparticles for efficient drug delivery in the treatment of colorectal cancer.

Abstract: A biogenic protocol has been adopted for the formulation of zinc ferrite nanoparticles (ZFNPs) using an aqueous extract of Allium cepa (AC) as a reducing agent for the optimization of its properties. The various characterization results from XRD, SEM, DRS, Raman, and VSM clearly showed that the formulated ZFNP was a single phase with crystallite size in the range of 11–15 nm. A spherical morphology was observed for all the samples with particle size in the range of 34–52 nm. All the samples showed a superparamagnetic behavior with reduced saturation magnetization. The ZFNPs prepared were used for self-heating analysis in hyperthermia applications at 180 Oe applied field and 425 Hz. It produced enough heating within the therapeutic temperature to attain the Curie temperature. The ZFNP formulated is auspicious for hyperthermia applications with less side effect owing to their biocompatibility, moderate Curie temperature, and SAR value within the therapeutic range. The formulated nanoparticles have further broadened the horizon of hyperthermia therapeutic applications with an innocuous protocol within 300 s.

Abstract: Nanotechnology has made an extensive headway in medicinal field over recent times with its application in specific targeting of diseases and drug delivery It furnishes all the possible path for current medical issues by employing smaller, faster, lighter, and better performing materials Different types of complex nanocarriers used in drug delivery system have evolved immensely emphasizing on minimum toxicity and higher efficiency This current review focuses on various organic and inorganic nanoparticle-based methodologies for targeted drug delivery along with a brief note on the evolving magnetic nanoparticles and drug delivery based on stimuli-responsive and biodegradable polymeric nanoparticles The implementation of nano-based delivery system for the treatment of tumor, coronary artery disease, Alzheimer’s disease, and diabetes mellitus has also been discussed in the paper Additionally, a crisp insight on some recent trends in nanocarrier discoveries for safe and personalized drug delivery system, drug resistance overcome by nanotechnology, and some possible way outs from the appeared shortcomings have been provided The aim of this study majorly focuses on the large-scale importance of nanomedicines in improving the therapeutic outcome of numerous drugs with special reference to few pre-eminent disease therapies articulated in detail through this review which has been accompanied by discussions on how nanotechnology has evaded the problems associated with traditional drug delivery system by altering basic properties of drugs On reaching the epilogue, we have a better understanding of the promising opportunities that nanotechnology bestows upon medical science and drug delivery for more specific and less toxic therapeutics

Abstract: Graphene, which is made up of single-layer sp2 graphite, has stimulated the interest of researchers in a variety of application fields, including electronics, pharmaceuticals, and chemicals, due to its superior properties. Large-scale production of graphene is essential for the material to be viable and widely used. One of the most efficient methods of accomplishing a huge amount at a reasonable cost is to exfoliate graphite to produce graphene. The purpose of this paper is to analyze several exfoliation procedures based on a common mechanical and chemical mechanism, because a detailed analysis of the exfoliation phenomenon can lead to valuable insights about how to generate high-quality graphene more economically by optimizing exfoliation approaches. In this study, the focus is given on the extensively employed mechanical exfoliation, such as micromechanical cleavage method, sonication method, ball milling method, and fluid mechanics method and chemical exfoliation, such as chemical vapor deposition and chemical method. This study will also focus on the chemical functionalization of graphene, such as covalent functionalization and non-covalent functionalization. This review will give a deep knowledge about graphite exfoliation and functionalization phenomenon, which will guide in the right way for commercial bulk graphene synthesis with less defects.

Abstract: In this study, we report the synthesis and characterization of novel nanocomposite namely doubly functionalized chloromethyl-calix[4]arene-methoxy grafted silylated clay (SC-C[4]). The silylation of nanoclay (thickness of the sheets ≈ 1 nm) was performed using (3-aminopropyl)trimethoxysilane (APTMS) (height ≈ 4.55 A) coupling agent. The resulting organoclay was characterized by various techniques such as X-ray diffraction (XRD), infrared spectroscopy (IR), thermal gravimetric analysis (TGA), and 29Si and 13C solid-state NMR. The XRD results suggested the presence of a double layer of silanes molecules into the clay galleries of nanoclay minerals by increasing in the basal spacing. While the IR, 29Si and 13C solid-state NMR, and TGA analysis demonstrated the successful silylation of clay by the appearance of novel absorption bands, the changes in the chemical environment and the peaks degradation in the range 200 to 500 ° C related to aminosilane molecules, respectively. The calix[4]arenes derivatives were synthesized and characterized by IR spectroscopy and 1HNMR. The results showed that calix[4]arene was functionalized at the lower and upper rim. The grafting of the doubly functionalized calix[4]arene onto clay surfaces was performed through nucleophilic reaction. Structure, thermal properties of the nanocomposite SC-C[4] were also investigated. All data approved the successful grafting of para-chloromethyl-calix[4]arene-OMe onto clay surfaces.

Abstract: The electronic sensitivity and reactivity of polyamidoamine (PAMAM) and polyester dendrimers toward favipiravir (T705) were inspected using density functional theory method. The T705 drug is adsorbed on the surface of PAMAM and polyester dendrimers with the binding energy of -27.26 and -26.80 kcal mol−1, respectively, in the solvent phase. The energy gap of PAMAM and polyester dendrimers reduced by about 32% and 27%, indicating that the electrical conductance of carriers become 8.16 × 1023 and 4.41 × 1022 times higher, upon T705 adsorption. The work function (Φ) value of PAMAM and polyester is changed about 1.53 and 0.71 eV, respectively. Thus, PAMAM dendrimer is about 2.5 times stronger Φ-type sensor than polyester dendrimer. The recovery time for T705 desorption from the PAMAM and polyester surface is predicted to be 9.2 × 103 and 4.2 × 103 s, respectively, at physiological environment.

Abstract: This study aimed to evaluate the effectiveness of silver nanoparticles–chitosan composites (AgNPs) with different morphologies and particle size distributions against resistant bacteria and biofilm formation. Four different samples were prepared by a two-step procedure using sodium borohydride and ascorbic acid as reducing agents and characterized by UV–Vis absorption spectra, scanning transmission electron microscopy. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the AgNPs were determined according to the Clinical and Laboratory Standards Institute (CLSI) against clinical isolates multidrug-resistant and strains of the American Type Culture Collection (ATCC). An assay was performed to determine the MICs during 20 successive bacteria exposures to AgNPs to investigate whether AgNPs induce tolerance in bacteria. The antibiofilm activities of AgNPs were also evaluated by determining the minimum biofilm inhibitory concentration (MBIC). The spherical AgNPs present diameters ranging from 9.3 to 62.4 nm, and some samples also have rod-, oval-, and triangle-shaped nanoparticles. The MIC and MBC values ranged from 0.8 to 25 μg/mL and 3.1 to 50 μg/mL, respectively. Smaller and spherical AgNPs exhibited the highest activity, but all the AgNPs developed in this study exhibit bactericidal activity. There was no significant MIC increase after 20 passages to the AgNPs. Regarding the antibiofilm activity, MBICs ranged from 12.5 to 50 μg/mL. Again, smaller and spherical nanoparticles presented the best results with phenotypic inhibition of production of slime or exopolysaccharide (EPS) matrix. Thus, it was concluded that AgNPs have a promising potential against resistant bacteria and bacteria that grow on biofilms without inducing tolerance.

Abstract: We used triple-quadrupole and high-resolution inductively coupled plasma-mass spectrometry (ICP-MS) in single-particle mode to characterize the food additive E171 (titanium dioxide, TiO2) in chewing gum, chocolate candy, and cake decoration in the same sample extracts. Then, we spiked TiO2 particles (with similar characteristics as E171) to milk as an example of a calcium-rich matrix. The obtained particle size distributions with both techniques were highly similar in terms of shape and median and mean diameters. Median diameters were in the range of 123 to 209 nm and mean diameters from 146 to 223 nm. In addition, they were in agreement with results obtained by scanning electron microscopy and asymmetric flow field-flow fractionation coupled to multi-angle light scattering and ICP-MS. Repeatable determination of number-based particle size distributions was possible with both ICP-MS techniques even in a calcium-rich matrix showing that both instruments were similarly efficient in resolving the Ca interferences. The combination of spICP-MS with microscopy and TiO2 recovery allowed validating the methods and identifying the presence of aggregated/agglomerated particles in one sample. For the TiO2 powder and the two remaining food products, recoveries were higher than 60%. Both instruments are fit for purpose even if the analyses were performed with differences in detector mode, dwell times, and calculation tools. This shows that both techniques may be used as long as operating conditions are optimized and applicability range is defined.

Abstract: Doped carbon-based materials have attracted considerable attentions due to their extraordinary optical, thermal, and electronic properties Herein, we demonstrate a facile and universal approach, which involves the hydrothermal treatment of citric acid and phosphonitrilic chloride trimer (Cl6N3P3), for the production of nitrogen and phosphorus co-doped graphene quantum dots (N, P-GQDs) The obtained N, P-GQDs with a mean size of about 34 nm exhibit bright yellow fluorescence, good-solubility, and attractive optical stability Although the quantum yield as high as 348% has been proved in our synthesized N, P-GQDs, the fluorescence can be also fleetly and selectively quenched by Fe3+ ions Therefore, high-performance Fe3+ sensors are fabricated with N, P-GQDs, with an ultra-sensitive detection limit of 146 nM Furthermore, high ionic strength, mild acids, and alkaline are demonstrated to have a small impact on the fluorescence intensity of the N, P-GQDs Finally, the as-synthesized N, P-GQDs, with bright luminescence and excellent biocompatibility, are applied for bioimaging, eg, fibroblast cells

Abstract: Nonclassical continuum mechanics theories have seen a rise in implementation over the past several years due to the increased research into micro-/nanoelectromechanical systems (MEMS/NEMS), micro-/nanoresonators, carbon nanotubes (CNTs), etc. Typically, these systems exist in the range of several nanometers to the micro-scale. There are several available theories that can capture phenomena inherent to nanoscale structures. Of the available theories, researchers utilize Eringen’s nonlocal theory most frequently because of its ease of implementation and seemingly accurate results for specific loading conditions and boundary conditions. Eringen’s integral nonlocal theory, which leads to a set of integro-partial differential equations, is difficult to solve; therefore, the integral form was reduced to a set of singular partial differential equations using a Green-type attenuation function. However, a so-called paradox has arisen between the integral and differential formulations of Eringen’s nonlocal elasticity. For certain boundary and loading conditions, instead of the expected softening effect inherent in nonlocal particle interactions, some researchers have found a stiffening effect. Still, others have found no variation from those results found using classical theories. As such, the discrepancies between the integral and differential forms have been the subject of debate for nearly two decades, with several proposed resolutions published in recent years. This paper serves to review and consolidate existing theories in nonlocal elasticity along with selected theories in nonclassical continuum mechanics, the utilization of Eringen’s nonlocal elasticity in beams, shells, and plates, the existing discrepancies and proposed solutions, and recommendations for future work.

Abstract: As a substitute for pure silver nanoparticles, Cu-Ag core-shell nanoparticles (CS NPs) have received significant attention in the fields of electronic packaging and conductive inks. Shell thickness is one of the important factors affecting the sintering performance of CS NPs. In this work, we conduct a multi-particle molecular dynamics simulation to investigate the shell thickness effects on the sintering process of Cu-Ag CS NPs at different temperatures. The results show that the less the shell thickness, the lower the potential energy decrease during sintering. This study mainly involves two sintering mechanisms, plastic deformation mechanism, and diffusion mechanism. During the sintering process, the contribution of the plastic deformation mechanism decrease with the layer thickness decreases. As for the diffusion mechanism, the self-diffusion coefficient at 500 K is much lower than that at higher temperatures. However, the slow diffusion can increase the densification by filling the pores generated in the initial stage of sintering. The self-diffusion coefficient of surface atoms increases as the shell thickness decreases. The decrease of shell thickness can produce more lattice mismatches at the core-shell interface, which hinders crystallization during the sintering process. And we found more amorphous Ag atoms at the sintering neck. A higher sintering temperature can induce the diffusion of Cu atom near the core-shell interface, especially for the particle with thinner shell thickness. Some diffused Cu atoms were found in the neck area of sintered CS NP of Ag5Cu3.5 and Ag5Cu4 at 700 K. Moreover, the sintered neck partly composed of Cu atoms was observed in sintered Ag5Cu4 CS NPs at 900 K.

Abstract: An investigation was conducted to examine the extent to which the thermal conductivity of materials in polyethylene glycol (PEG) fluids could be improved using the concept of hydrogen bonding and long chains. Boron nitride (BN), hydroxyl functionalized multiwall nanotube (MWNT-OH), and carbon nanofibers (CNFs) were mixed and exfoliated to form hydrogen bonds between the particles and the PEG fluids. Following this bonding process, clear enhancements in the thermal conductivity were observed. In addition, the long chain boron nitride nanotubes (BNNTs) and carbon nanofibers were shown to significantly enhance the thermal conductivity, due to the resulting increase in the contact and interfacial surface areas. The results of this experimental investigation indicated that PEG400 with a loading of 7.5 wt% MWNT-OH yielded a thermal conductivity increase as high as 89.7% over the base fluid. PEG400 loaded with a combination of 2 wt% CNF and 2 wt% BNNT resulted in a thermal conductivity increase of 73.1%. These results are significantly higher than the best results previously reported in the literature and may in part be attributed to the use of a three roll milling technique to enhance contact. The results presented here will open the way for further exploration of the use of novel phase change materials for thermal energy storage applications.

Abstract: This study presents a systematic study in which sodium borohydride and hydrazine were used successively as reducing agents for the synthesis of nickel nanoparticles in an aqueous medium. The size of nickel nanoparticles could be controlled ranging from 11 to 48 nm by adjusting the concentration of hydrazine and the reaction temperature. A product yield of synthesized nanoparticles could achieve as high as 86.5%. As alternatives to silver pastes in some applications, nickel pastes have attracted growing interest because of the lower cost. By the use of nickel nanoparticles as fillers of the conductive pastes, low temperature sintering can be achieved. To avoid film cracking and to improve conductivity, bimodal screen-printing pastes containing different weight ratios of nickel microparticles and nanoparticles were prepared. A micro-to-nanoparticle weight ratio of 2 was found to be the optimal ratio for the nickel paste formulation, resulting in a volume resistivity of 122 μΩ∙cm for a printed film after sintering at a targeted temperature of 600 °C.

Abstract: The size and shape of silver nanoparticles (AgNPs) can potentially influence their antibacterial activity. In this study, a photochemical approach was adopted for the synthesis of decahedral AgNPs and their antibacterial activity was tested and compared against that of spherical AgNPs of similar size synthesized using the chemical reduction approach. The UV–vis spectra indicated the synthesis of decahedral AgNPs with a localized surface plasmon resonance (LSPR) peak at 502 nm. The spherical AgNPs exhibited the LSPR peak at 416 nm. Analysis of field emission gun-transmission electron microscopy (FEG-TEM) micrographs demonstrated the average diameter of decahedral silver nanoparticles as 52.1 ± 5.7 nm with side length as 33.2 ± 3.1 nm. In contrast, the average size of spherical AgNPs was 44.2 ± 6.3 nm. The decahedral AgNPs demonstrated ten times higher bactericidal activity as compared to the spherical AgNPs across all the bacterial strains tested. The minimum inhibitory concentration (MIC) for decahedral AgNPs was in the range of 4–8 μg/ml for all the four bacterial strains tested, whereas, for spherical nanoparticles of comparable size, the MIC was in the range of 40–80 μg/ml. The minimum bactericidal concentration (MBC) for decahedral AgNPs was in the range of 6–10 μg/ml. At the same time, spherical AgNPs of comparable size exhibited MBC in the range of 60–100 μg/ml for the four bacterial strains. In terms of bactericidal effect, Escherichia coli MTCC 443 was found as the most sensitive strain, while in terms of growth inhibition, Bacillus subtilis was the most sensitive strain. Staphylococcus aureus NCIM 5021 was the most resistant among the tested bacterial strains.

Abstract: Poly-lactic-co-glycolic acid (PLGA) was mixed with gentamicin sulfate via a double emulsion method, resulting in gentamicin-loaded PLGA nanoparticles that exhibited excellent antibacterial properties and great potential in fabricating smart wound dressings integrated with a drug delivery system. The nanoparticle morphologies, particle degradation rates, drug release profiles, and antibacterial properties were investigated using scanning electron microscopy (SEM), dynamic light scattering (DLS), ultraviolet–visible spectroscopy (UV–vis), and disk diffusion method. Nanoparticles prepared at different PLGA concentrations exhibited different release profiles that were determined by multiple release mechanisms including diffusion, osmotic pumping, and nanoparticle degradation. The antibacterial activities were measured using a disk diffusion method indicating that various nanoparticles loaded with antibiotics can control bacterial infection to some degree proving that nanoparticles used in this paper can be used in the pharmaceutical industry. The results suggested that drug release properties of gentamicin loaded PLGA nanoparticles can be affected by PLGA concentrations and PVA concentrations in the particle synthesis, providing a guidance in preparing gentamicin-loaded PLGA nanoparticles for topical antibiotics delivery applications. The nanoparticles with a spherical and uniformly porous structure were prepared with a PLGA concentration of 0.0167 g/ml and a PVA concentration of 12%, resulting in the highest average gentamicin release rate and excellent antibacterial activities. Four release mechanisms (diffusion through polymer, diffusion through pores, osmotic pumping, and nanoparticle degradation) primarily determined the gentamicin release process.

Abstract: Pesticides play a significant key role in the agriculture sector. In India, there is a sharp increase in pesticides consumption in recent years, leading to severe implications. Due to the rapid use of pesticides, there is residue in the food, which leads to poor effects on human health. Furthermore, the discharge of various pesticides into water bodies from the industries and agricultural activities leads to environmental concerns. Because of their toxicity, persistent nature, and bioaccumulation potential, it is essential to remove pesticides from water. Nanoparticles are tiny particles whose size ranges from 1 to 100 nm. Nanomaterials have a large surface area, a large number of active sites, and high reactivity. Therefore, nanotechnology is a fast, efficient, and economical process. Nanotechnology plays an influential role in the removal of various pesticides from water and wastewater. In recent years, various nanomaterials, such as TiO2, ZVI, Zn, and rGO (reduced graphene oxide), CNTs (carbon nanotubes), and polymer-supported nanomaterials are widely used for the removal of pesticides from water. In this review, detailed information about various pesticides and their removal with the help of nanocomposites has been discussed.

Abstract: Stretchable conductors are receiving increasing attention due to their potential applications in wearable electronics. Highly stretchable conductors are fabricated using composites of silver nanowires (Ag NWs) and flakes on elastic polydimethylsiloxane (PDMS) substrates. The resistance of the Ag NW/flake composite conductor decreases to 1.9 × 10−4 Ohm·cm and increases by only 1.8 times after 100 stretch/release cycles at 100% peak strain. The improved conductivity and stretchability of the composite conductors are due to the synergy between the Ag NWs and Ag flakes because the Ag NWs connect the Ag flakes as conductive cables and the Ag flakes fill the gaps among the Ag NWs. Robust Ag NW/flake conductors are promising candidate for wearable electronics.

Abstract: A theoretical study on the interactions between X12Y12 nanocages (Al12N12, Al12P12, B12N12, and B12P12) and putrescine molecule (Put) is presented, using density functional theory (DFT) B3LYP/6-31+G(d) methodology. Structural, energetic, and electronic variations were observed for putrescine molecules adsorbed in nanocages, and results showed that (1) the highest transferred charges (0.37 e−) of Put on nanocages found were of B12N12 and B12P12, as well as the lowest bond length interaction with putrescine X12Y12-Put (1.62 A and 1.64 A, respectively); (2) X12Y12-Put adsorption interaction is chemical in nature, and adsorption energy is in the order of Al12N12 > B12N12 > Al12P12 > B12P12; however, only the B12P12 presented low recovery time (113 s), showing that it is well suited to avoid spontaneous desorption at room temperature; and (3) the electronic properties of nanocages were affected by their interaction with putrescine, with a significant decrease in band gap (Eg) of frontier molecular orbitals (9.46 %) for B12P12 and in work function (Φ) (19.53% and 13.69%) for Al12N12 and B12P12, causing an increase in the electrical conductivity and an increase in the density of electron current. Based on calculated results, B12P12 nanocage has potential applications as conductometric and work function-type sensors for the determination of putrescine molecule.

Abstract: Nanostructures are capable of major changes in our life. However, the game changing properties of experimental nanostructures mostly are not repeatable for the industry and it is not easy to produce the amount of nanoparticles necessary for the industrial world. Repeatable methods, which do not require highly trained personnel, for industrial-scale production should be developed to transfer the academic research to the use of people. Although there are various successful microfluidics devices that have been designed for microstructures synthesis, the synthesis of the nanostructures is not an enlightened area and there is a need for research to reach a better state. Especially, the development and design of microfluidics devices for biopolymeric nanoparticles are very important. The biopolymeric nanoparticles have uses in both nanotechnology and nanomedicine especially as theragnostic tools. In this study, a microfluidic device has been modeled, designed, and manufactured for especially iron oxide core chitosan nanoparticles. The microfluidics channels were manufactured by 3D printing. After nanoparticles synthesized by manufactured device, these particles were characterized, and their properties were examined. In addition to the flow rate, chemical concentrations, and pH, the structure of the microfluidics channel and hurdles have effects on the particle size and particle size distribution. Best results were obtained with 120-120ml/h flow rates and 0.06-0.03% concentrations at pH 4.5 for chitosan-tripolyphosphate couple. The nanoparticles that were produced in microchannels with hurdles under these conditions have a DLS measurement of 190±15 nm in diameter with 69% intensity. In conclusion, the 3D printed microfluidic channels are able to synthesize nanoparticles in a reproducible way with or without iron oxide core.

Abstract: The exploration of electrode functional materials for supercapacitors may bring a revolution to energy storage devices to boost the portable industry. Herein, lanthanum sulfide nanorods and reduced graphene oxide (rGO)–templated lanthanum sulfide nanorods have been synthesized using the hydrothermal process. Structural, morphological, and compositional analyses were conducted using X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The specific surface area has been measured using the Brunauer–Emmett–Teller technique. Individual lanthanum sulfide and rGO-templated lanthanum sulfide showed the morphology of nanorods. Cyclic voltammetry tests predicted the pseudocapacitive nature of the lanthanum sulfides for supercapacitor applications. The rGO effectively improved the electrochemical characteristics of the lanthanum sulfide, which might be due to the facilitation of charge carriers through nanorods, as the rGO-templated lanthanum sulfide nanorod showed a specific capacitance of 75.17 F/g at a scan rate of 30 mV/s evidenced by cyclic voltammetry (CV) curves. The rGO significantly increased the discharge time from 60 to 188 s, specific capacitance from 20.32 to 34.12 F/g, and energy density from 572 to 1185 mW/kg compared to individual lanthanum sulfide nanorods as seen by the galvanostatic charge/discharge profile. The rGO-templated lanthanum sulfide nanorods showed a power density of 255.20 W/kg at a high current density of 0.2 A/g and a specific capacitance retention up to 91.60% for 2000 cycles at scan rate of 20 mV/s. Symmetric cell exhibited the specific capacitance of 94.45 F/g, energy density of 6.43 Wh/kg at the current density of 0.05 A/g, and power density of 351.25 W/kg at the current density of 0.2 A/g. The test results indicate that the use of rGO is effective in improving the electrochemical characteristics of lanthanum sulfide nanorods for supercapacitor applications.

Abstract: The production of nanomaterials for biomedical research and applications increases exponentially. Interestingly, there is an increase in the use of nanoparticles in pharmaceutical sciences for diagnosis and treatment purposes, and therefore, nano-toxicity becomes one of the major role aspects in the future of pharmaceutical nanotechnology. This study focused on discerning and identifying the main variables that govern a group of metal oxide nanoparticles’ toxicity in human keratinous cells (HaCaT), combining computational simulation and semiempirical calculations with the available experimental data allowed revealing and explaining the nanoparticle toxicity for the corresponding cell line, through the development and validation of an interpretive nano-QSAR model with acceptable statistical quality by applying a multivariate linear regression with a coupled genetic algorithm. This function included only two descriptors, orthogonal to each other: the enthalpy of a standard formation of metal oxide nanocluster $$ {\Delta \mathrm{H}}_{\mathrm{f}}^{\mathrm{c}} $$ and the absolute value of Fermi energy from the cluster $$ {\upepsilon}_{\mathrm{Fermi}}^{\mathrm{c}} $$ .The values of statistical indices obtained for this model showed its quality and robustness, for example, R2 = 0.90; $$ {\mathrm{Q}}_{\mathrm{cv}}^2 $$ = 0.86 and F = 37.15. This study demonstrated the need to use quantum-mechanical descriptors to explain the toxicity of metal oxide nanoparticles, capable of characterizing the electronic state of nanostructures. Regularization methods based on LASSO and Ridge regression have been employed in the model selection and validation. Furthermore, we propose a mechanism for toxicological effects applicable to a relevant group of nanoparticles, as well as their generalization to other toxicity studies not available in the literature, with potential nanopharmaceutical applications.

Abstract: A visible light-responsive redox-mediator-free calcium indium sulfide (CaIn2S4) and bismuth tungstate (Bi2WO6)–based direct dual semiconductor nanocomposites were prepared by combination of hydrothermal and wetness impregnation methods. The results substantiated the formation of CaIn2S4 marigold flowers, the flower-like structure of the Bi2WO6, and CaIn2S4/Bi2WO6 nanocomposites. UV–Vis-DRS analysis confirmed that visible light response of Bi2WO6 was considerably enhanced after combining with CaIn2S4. The inter-cross-sectional charge carrier transfer during photocatalysis using synthesized catalysts was studied by determining the band position of Bi2WO6 and CaIn2S4, and photoluminescence analysis. The adsorption of rhodamine B (RhB) dye study revealed that after coupling with CaIn2S4, the adsorption capacity of Bi2WO6 was significantly improved. For 15%-CaIn2S4/Bi2WO6, 38% of RhB dye was adsorbed, whereas it was 27% for bare Bi2WO6. The 15%-CaIn2S4/Bi2WO6 nanocomposite showed higher percentage degradation for RhB (82%) dye as compared to the other percentage loaded composites, bare Bi2WO6 (59%) and CaIn2S4 (72%). Photoluminescence results revealed that photo-generated electron–hole pair recombination rate was drastically suppressed after coupling with CaIn2S4 which may be presumed to inter-cross-sectional transfer of photo-generated charge carriers. The synergic effect of enhanced adsorption capacity and efficient separation of electron–hole pairs were accountable for the enhanced photodegradation efficiency under visible light.

Abstract: Recently, hydrogels have attracted considerable interests due to their intrinsic flexibility and adjustable mechanical properties. However, the integration of high conductivity, enhanced mechanical performance, and plasticity into one single hydrogel is still challenging. In this work, TEMPO-oxidized cellulose nanofibers (TOCNF, diameter 20–50 nm, length $$\ge$$ 1 um) are used as the efficient dispersant of multiwalled carbon nanotubes (MWCNTs, out diameter 5–15 nm, length 10–30 um). Conductive hydrogels are prepared through a simple one pot process and freeze–thaw cyclic method in combination with Fe3+ ions and TOCNF-MWCNT dispersions in polyvinyl alcohol (PVA) hydrogels. The resulting hydrogels demonstrate high water content (~ 88.8%), mechanical properties (ultimate stress of 1.1 MPa, strain of 336%), and conductivity (0.57 S/m), which can be applied to the preparation of stress or strain sensors. The hydrogel-based resistance sensor is applied to human motion detection, showing a sensitivity of 1.876 kPa−1 with pressure lower than 16 kPa. Similarly, the hydrogel-based capacitive sensor can detect imperceptible pressure of 20 Pa. In addition, the hydrogels also reveal excellent plasticity. In conclusion, the conductive hydrogel possesses excellent comprehensive properties, providing inspiration and potential for the preparation and application of wearable strain sensors.

Abstract: This paper presents a foresight perspective of nanotechnology in South Africa based on a 20-year period scientometric analysis of the country’s nanotechnology publications on the Web of Science (WoS) Core Collection. Firstly, publication trends are reported; then, possible socio-economic relevant sectors arising from this information are determined. Lastly, indicators that can be used in foresight exercises to evaluate the potential nanotechnology research areas in South Africa are examined. The 20-year review is also compared with the recent past year, 2019, to identify any changing trends. South Africa’s nanotechnology publications per year grew exponentially from 68 papers in 2000 to 1672 in 2019, an increase of 2459%. The total share of nanotech publications increased from 1.4% in 2000 to 6.6% in 2019, thus a 0.52% increase per year. Compared with Brazil, Russia, India and China, the BRICS countries, South Africa has the lowest nanotechnology productivity with an activity index of 0.68. Over the last 5 years, South Africa nanotech publications had a Hirsch-index of 94 and an average citations rate of 12.76 per paper. Universities are the most prominent publishers, and there are very few publications from the private sector, which can negatively impact the commercialisation of nanotechnology research. The top 10 most prolific researchers, author or co-author over 20% of the nanotechnology papers are reported. A mixture of old and new top researchers’ names suggests succession planning in the system as the years progress. The emergence of computer science as one of the top 20 subjects publishing in nanotech in 2019 and a high level of researcher collaboration suggests possible convergence of nanotech, information technology and artificial intelligence in South Africa. The strategic socio-economic-focused nanotechnology research areas identified for South Africa include material science, photoluminance and optics, medicine, catalysis, electronics, energy, biotech, magnetism, sensors, water and communicable diseases. The top collaborating countries, top researchers, top institutions and nanotechnology economic hubs are reported for each strategic research area. The level of innovation was evaluated using the nanotechnology value chain, and there is a meagre 3.5% of papers reporting on nano-enabled products.

Abstract: Upscaling of nanoparticle fabrication by sputtering into an ionic liquid is shown for the example of Cu. Long-time sputtering (24 h) into a large amount (50 mL) of the ionic liquid 1-butyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide [Bmim][(Tf)2 N] yields an amount of approximately 1 g Cu nanoparticles (mean spherical diameter (2.6 ± 1.1) nm), stabilized in ionic liquid without agglomerations. Extraction of Cu nanoparticles from the stabilizing ionic liquid was performed with the capping agent hexadecylamine. Extracted particles could be redispersed in other solvents, thus enabling applications of sputtered nanoparticles beyond ionic liquids.

Abstract: Metal nitrogen-carbon catalysts have become a promising alternative to platinum-based catalysts in fuel cells due to their high stability and platinum-like activity. However, the corrosion and deactivation of active sites in the solution still restrict the inherent reaction kinetic rate. For this reason, it is important to stabilize the catalyst through a controllable doping strategy to obtain high activity catalysts for oxygen reduction reactions (ORR). Herein, the pyrolysis strategy is demonstrated in the synthesis of iron-based catalysts co-doped with nitrogen and biomass-derived phosphorus (denoted as N, P-Fe/C), and the pore size of the catalyst is mostly distributed at 1 nm or 50 nm, respectively. The half-wave potential (0.893 V) and the current density (4.05 mA cm−2) at 0.85 V of the catalyst exceed those of the commercial Pt/C. The remarkable ORR performance can be attributed to its distinct hierarchical pore structure, the modulation effect of nitrogen and phosphorus co-doping on the carbon matrix, and the combined effect of the FeNx active sites, which improves the accessibility of reactants and accelerating the absorption/desorption of the reaction intermediate, thereby increasing reaction rates. And N, P-Fe/C has great potential as a promising substitute for platinum-based catalysts.