Current Nanoscience - Volume 16, Issue 5, 2020

Background: Nanoparticulate systems like nanospheres, nanocrystals, and nanofluids show immense advancement in the fields of nanoelectronic and agriculture. Nanobulges are duplexed nanoparticles comprising the interaction of two nanoparticles for the formation of a curved bulge on the surface of the nanoparticle. Objective: This review focuses on properties, mechanism of action, methods of preparation and applications of nanobulges in optoelectronic devices and controlled release of fertilizers. Methods: Mostly pulsed laser deposition and multilayered palladium-catalysts fabrication with nanobulges structure are used to prepare nanobulges. Results: Nanobulges are advantageous over the conventional nanoparticles due to their high electrical density, improved catalytic drug loading and good electronic conductivity. Conclusion: In the near future, nanobulges will emerge as a promising material for commercial preparation of bioanalytical sensors and microfluidic systems.

Ischemic stroke, which is the fifth leading cause of death, is an attack in the brain due to blockage of a brain artery. It occurs when a sudden loss of blood flow to the brain leads to a reduction in the oxygen supply. A wide range of reasons have been found for ischemic stroke, including high blood pressure and associated thrombosis. Suitable biomarker analysis followed by proper treatment helps to prevent ischemic stroke. An aptamer is an artificial antibody generated against various clinical biomarkers from a smaller molecule of a whole cell. Recently, several researchers conducted biomarker analysis for ischemic stroke using aptamers. Furthermore, factor IX, which is a blood clotting factor, is highly correlated with thrombosis and plays a role in ischemic stroke. In this review, we summarized the potential role of aptamers in ischemic stroke by nanoscale analysis, and factor IX was the distinct focus of this review.

The pace at which nanotheranostic technology for human disease is evolving has accelerated exponentially over the past five years. Nanotechnology is committed to utilizing the intrinsic properties of materials and structures at submicroscopic-scale measures. Indeed, there is generally a profound influence of reducing physical dimensions of particulates and devices on their physico-chemical characteristics, biological properties, and performance. The exploration of nature’s components to work effectively as nanoscaffolds or nanodevices represents a tremendous and growing interest in medicine for various applications (e.g., biosensing, tunable control and targeted drug release, tissue engineering). Several nanotheranostic approaches (i.e., diagnostic plus therapeutic using nanoscale) conferring unique features are constantly progressing and overcoming all the limitations of conventional medicines including specificity, efficacy, solubility, sensitivity, biodegradability, biocompatibility, stability, interactions at subcellular levels. This review introduces two major aspects of nanotechnology as an innovative and challenging theranostic strategy or solution: (i) the most intriguing (bare and functionalized) nanomaterials with their respective advantages and drawbacks; (ii) the current and promising multifunctional “smart” nanodevices.

HAART (Highly Active Antiretroviral Therapy) revolutionized HIV (Human Immunodeficiency Virus) treatment upon its introduction in 1996. But, HAART has not been a complete solution for HIV infection. HIV remains viable in latent viral reservoirs even when the adequate concentration of a drug is available in the blood. Hence, nanotechnology-based delivery systems are being developed to target the HIV virus and evaluated for their safety and efficacy. Among employed nanocarriers, dendrimers are repetitively branched molecules which are an ideal carrier for developing preventive antiretroviral drug delivery system with low-level cytotoxicity and targeted action. Dendrimers with potentially active multivalent sites combine with the gp120 of HIV and CD4 receptors of the host cells and inhibit the attachment of HIV to host cells. Some of the dendrimers are capable of interfering in HIV replication. The main objective of this review is to reveal the mechanism of anti-retroviral action of different types of functionalized dendrimers in HIV. The significance of dendrimers as therapeutic agents for targeting the viral reservoirs in case of HIV was discussed. From the published literature reviewed, it can be concluded that the functionalized dendrimers are useful as anti-HIV agents and highlighting that advance studies are required for the development of more effective dendrimers based therapy which noticeably increases the anti-HIV activity.

Background: Paclitaxel and spirulina when administered as nanoparticles, are potentially useful. Methods: Nanoformualtions of Paclitaxel and Spirulina for gastric cancer were formulated and optimized with Central composite rotatable design (CCRD) using Response surface methodology (RSM). Results: The significant findings were the optimal formulation of polymer concentration 48 mg, surfactant concentration 45% and stirring time of 60 min gave rise to the EE of (98.12 ± 1.3)%, DL of (15.61 ± 1.9)%, mean diameter of (198 ± 4.7) nm. The release of paclitaxel and spirulina from the nanoparticle matrix at pH 6.2 was almost 45% and 80% in 5 h and 120 h, respectively. The oral bioavailability for the paclitaxel spirulina nanoparticles developed is 24.0% at 10 mg/kg paclitaxel dose, which is 10 times of that for oral pure paclitaxel. The results suggest that RSM-CCRD could efficiently be applied for the modeling of nanoparticles. The paclitaxel and spirulina release rate in the tumor cells may be higher than in normal cells. Paclitaxel spirulina nanoparticle formulation may have higher bioavailability and longer sustainable therapeutic time as compared with pure paclitaxel. Conclusion: Paclitaxel-Spirulina co-loaded nanoparticles could be effectively useful in gastric cancer as chemotherapeutic formulation.

Background: Hybrid nanofluids are considered as an extension of conventional nanofluids which are prepared through suspending two or more nanoparticles in the base fluids. Previous studies on hybrid nanofluids have measured their thermal conductivity overlooking other thermophysical properties such as viscosity and electrical conductivity. Objective: An experimental investigation is undertaken to measure thermal conductivity, viscosity, and electrical conductivity of a hybrid nanofluid prepared through dispersing alumina nanoparticles and multiwall carbon nanotubes in saltwater. These properties are the main important factors that must be assessed before performance analysis for industrial applications. Methods: The experimental data were collected for different values of the nanoparticle volume fraction, temperature, salt concentration, and pH value. Attention was paid to explore the consequences of these parameters on the nanofluid’s properties and to find optimal conditions to achieve the highest value of the thermal conductivity and the lowest values of the electrical conductivity and the viscosity. Results: The results demonstrate that although the impacts of the pH value and the nanoparticle volume fraction on the nanofluid’s thermophysical properties are not monotonic, optimal conditions for each of the properties are reachable. It is found that the inclusion of the salt in the base fluid may not change the thermal conductivity noticeably. However, a considerable reduction in the viscosity and substantial elevation in the electrical conductivity occur with an increase in the salt concentration. Conclusion: With the addition of salt to a base fluid, the thermophysical properties of a nanofluid can be controlled.

Background: Herbicides are very beneficial in the crop yield with the aid of controlling weeds within the agriculture, but several herbicides are chronic in soil. Objective: In this study, nanoparticles and the packages of synthesized novel silica nanoparticles were studied for the preconcentration of herbicides. Methods: These nanoparticles prepared by the Stöber mechanism were purified and functionalized. Nanoparticles thus prepared successfully were used as supporting material for the preconcentration of residues of herbicides in the water. Results: Preconcentration was achieved by preparing the silica-based solid-phase-extraction cartridges. Nanoparticles used for this purpose were within the range of 50-250 nm. An SPE cartridge was prepared by packing 200 mg of silica nanoparticle in the empty cartridge of diameter 5.5 cm and length 0.6 cm in between PTFE frits. Aqueous solutions of 0.1 μg/ml of herbicides were prepared separately, and 10 ml of the solution was passed through the cartridge at the rate of 0.2 ml/min. After passing 10 ml volume of the aqueous solution, residues adsorbed on the cartridge were eluted using 2 ml of acetonitrile. The eluate was injected to determine the herbicide residue adsorbed on the SPE cartridge. Conclusion: In the study, it was found that greater than 90% of the herbicide residues were trapped on silica nanoparticle-based SPE cartridge. An analytical method was developed for the simultaneous determination of these herbicides. The residues were quantified by LC-MS/MS with ESI mode.

Background: A major focus of nanotechnology concerns is the expansion of the optimization of nanomaterials in purity, size and dispersity. Methods: In the current work, a two-step AgNP synthesis process was optimized at the mycelia-DI water suspension and AgNP formation reaction levels. Results: Biomass filtrate from the fungal strain Tritirachium oryzae W5H was able to reduce silver nitrate into AgNPs after a 72 h reaction, as indicated by the development of intense brown color and by UV-vis spectra. The biosynthesis ability of AgNPs was markedly better in the presence of a single carbon and nitrogen source in the culture medium compared to multiple sources of carbon and nitrogen. The optimization results of AgNP formation were indifferent between the two steps and were 20 g biomass, 40°C, pH 7.0, 96 h and 1.0 mM AgNO3. The TEM images of the prepared AgNPs illustrated the presence of 7-75 nm, monodispersed and spherical- to ovular-shaped Ag nanoparticles. Conclusion: The present work highlights the importance of investigating the process parameters by which the reductant mycelia-free filtrate was prepared. In addition, we explored the promising antibacterial action of the prepared AgNPs against bacterial infections.

Background: Recently, superparamagnetic and electromagnetic nano-materials have been extensively studied and their potential applications have also been investigated in various fields. In this regard, currently, Fe3O4 NPs are valuable candidates as diagnostic agents such as magnetic resonance imaging, enzyme immobilization, biosensing and cell labeling, and therapeutic probes, including drug delivery, bacteria detection, magnetic separation, and hyperthermia agents. Objective: In this study, electrochemical synthesis of Cu2+ cations-doped superparamagnetic magnetite nanoparticles (Cu-SMNPs) and their in situ surface coating with saccharides (i.e., glucose, sucrose and starch) are reported. The prepared glucose/Cu-SMNPs, sucrose/Cu-SMNPs and starch/Cu-SMNPs samples are characterized by structural, magnetic and morphological analyses by XRD, FT-IR, FE-SEM, EDAX and VSM. The suitability of the prepared samples for biomedical use is also proved. Methods: A simple cathodic electrochemical set-up was used to fabricate the iron oxide samples. The bath electrolyte was one litre deionized water containing 1.5g iron chloride, 3g iron nitrate, 0.5g copper chloride and 0.5g saccharide (i.e., glucose or sucrose or starch). The cathode and anode electrodes were connected to a DC power supply (PROVA 8000) as the power source. The deposition experiments were conducted at 10 mA cm-2 for 30 min. For the preparation of glucose/Cu-SMNPs, sucrose/Cu-SMNPs and starch/Cu-SMNPs samples, three electrodeposition experiments were carried out in three similar baths with only a change in the dissolved saccharide type. The prepared SMNPs samples were characterized by structural, morphological and magnetic analyses including X-ray powder diffraction (XRD, a Phillips PW-1800 diffractometer Smart Lab), field-emission scanning electron microscopy (FE-SEM, Mira 3-XMU with accelerating voltage of 100 kV), transmission electron microscopy (TEM, model Zeiss EM900 with an accelerating voltage of 80 kV), fourier transform infrared (FT-IR, a Bruker Vector 22 Fourier transformed infrared spectrometer) and vibrating sample magnetometers (VSM, model Lakeshore 7410). Results: Three types of metal-cations doped superparamagnetic magnetite nanoparticles (SMNPs), glucosegrafted Cu2+-doped MNPs (glucose/Cu-SMNPs), sucrose-grafted Cu2+-doped SMNPs (sucrose/Cu-SMNPs) and starch-grafted Cu2+-doped SMNPs (starch/Cu-SMNPs), were prepared for the first time. Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy and energy dispersive X-ray techniques proved the presence of saccharide capped layer on the surface of deposited SMNPs and also copper cations doping on their crystal structures. Superparamagnetic behaviors, including low coercivity and remanence values, were observed for all the prepared samples. Conclusion: SMNPs capped with saccharides (i.e., glucose, sucrose and starch) were successfully synthesized via one-pot simple deposition procedures. These particles showed suitable superparamagnetic properties with negligible remanence values and proper saturation magnetization, thus proving that they all have required physicochemical and magnetic characteristics for biomedical purposes.

Background: Increasing the bioactivity of metallic implants is necessary for biomaterial applications where hydroxyapatite (HA) is used as a surface coating. In industry, HA is currently coated by plasma spraying, but this technique has a high cost and produces coating with short-term stability. Objectives: In the present study, electrophoretic deposition (EPD) was used to deposit nano-biphasic calcium phosphate compound (β-tri-calcium phosphate (β-TCP) /hydroxyapatite (HA)) bio-ceramics on the titanium surface. The microstructural, chemical compositions and bioactivity of the β- TCP/HA coatings were studied in a simulated body fluid solution (SBF). Methods: Scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR) were used. Additionally, the antibacterial effect was studied by the agar diffusion method. The corrosion behavior of the β-TCP/HA coating on titanium surface (Ti) in the SBF solution at 37oC was investigated by means of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests. Results: The Ti surface modification increased its biocompatibility and corrosion resistance in the simulated body fluid. The antibacterial inhibition activity of the β-TCP/HA bio-ceramic was enhanced by electroless silver deposition. The enhanced properties could be attributed to the use of nano-sized biphasic calcium phosphates in a low-temperature EPD process. Conclusion: The β-TCP/HA and β-TCP/HA/Ag coatings well protect Ti from the corrosion in SBF and endow Ti with biocompatibility. The β-4-TCP/HA/Ag/Ti substrate shows good antibacterial activity.

Background: Today, nanoparticles hold great promise in biomedical researches and applications including bacteria detection. The rapid and sensitive outcomes of bacteria detection strategies using nanoparticle conjugates become determinative, especially in bacterial outbreaks. In the current research, we focused on detecting V. cholera bacteria and its toxin using a thiocyanate/Au nanoparticle. Thiocyanate adsorbed strongly on the surface of gold nanoparticles and changed the surface by enhancing surface plasmon resonance of gold nanoparticles. Objective: This method is tried to introduce a simple and fast procedure to assay vibrio cholera. So, it is observed by the naked eyes as well. Methods: We used two antibodies (Ab) for V. cholera detection: a) a primary antibody conjugated to magnetic nanoparticles (MNPs) for trapping V. cholera bacterial cells, and b) a secondary Abconjugated thiocyanate-GNPs as a colorimetric detector. Then, an immuno-magnetic separation system connected to a colorimetric assay was designed based on the GNPs. The results were measured by ultraviolet-visible (UV-Vis) spectroscopy. Results: The results showed that gold nanoparticles are an appropriate optical assay for detecting biological samples in a minimum concentration and also it can be easily seen by the naked eyes. The linear range of this biosensor is 3.2×104 to 28×104 cells per ml. Conclusion: In this research, a colorimetric immune assay based on gold nanoparticles was designed to improve the sensitivity of V. cholera detection. Also, this method can be used for the detection of other biological agents.

Background: Removal of the organic pollutants using the photo-catalysts by the photocatalytic treatment process under natural sunlight irradiation has attracted great attention owing to the complete destruction of the organic pollutants. The La bismuthate nanorods possess good photocatalytic performance for the removal of the methylene orange (MO) under the sunlight irradiation. Objective: The aim is to synthesize La bismuthate nanorods by hydrothermal method and research the photocatalytic performance of the La bismuthate nanorods for MO degradation under sunlight irradiation. Methods: La bismuthate nanorods have been synthesized by a simple sodium dodecyl benzene sulfonate (SDBS)-assisted hydrothermal method using sodium bismuthate and La acetate as the starting materials. The obtained La bismuthate products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy and solid UV-vis diffuse reflectance spectrum. Results: With different SDBS concentration, hydrothermal temperature and reaction time, different morphologies of the La bismuthate products were obtained. XRD analysis shows that the La bismuthate nanorods obtained from 180°C for 24 h with 5wt.% SDBS are composed of orthorhombic La1.08Bi0.92O3.03 phase. Electron microscopy observations show that the La bismuthate nanorods with flat tips have the length of longer than 10 μm and diameter of about 20-100 nm, respectively. The morphology and structure of the products are closely related to the SDBS concentration, hydrothermal temperature and reaction time. Solid UV-vis diffuse reflectance spectrum shows that the band gap of the La bismuthate nanorods is 2.37 eV. The La bismuthate nanorods show good photocatalytic performance for the degradation of MO under the sunlight irradiation. MO solution with the concentration of 10 mg.L-1 can be totally removed by 10 mg La bismuthate nanorods in 10 mL MO aqueous solution under sunlight irradiation for 6 h. Conclusion: The photocatalytic performance for the removal of MO is dependent on the sunlight irradiation time and dosage of the La bismuthate nanorods. The La bismuthate nanorods exhibit great potential for the removal of organic pollutants.

Background: Cerium oxide nanoparticles (nanoceria) are efficient free-radical scavengers due to their dual valence state and thus exhibit optical and catalytic properties. Therefore, the main purpose of this work was to understand the peroxidase mimic activity of polymer-stabilized nanoceria for enzyme-less H2O2 sensing by fluorescence spectrometer. Objective: This research revealed the development of fluorescence hydrogen peroxide nanosensor based on the peroxidase-like activity of polyacrylic acid stabilized nanoceria (PAA-CeO2 Nps). Methods: PAA-CeO2 Nps were synthesized by simple cross-linking reaction at a low temperature and characterized by XRD, SEM, Zeta potential, TGA, FT-IR and UV-VIS spectroscopic analysis. H2O2 sensing was performed by a fluorescence spectrometer. Results: The synthesized polymer nanocomposite was characterized by XRD, SEM, TGA, FT-IR and UV-VIS spectroscopic analysis. The XRD diffraction patterns confirmed the polycrystalline nature and SEM micrograph showed nanoparticles having hexagonal symmetry and crystallite size of 32 nm. The broad peak of Ce–O bond appeared at 508 cm-1. UV-VIS measurements revealed a welldefined absorbance peak around 315 nm and an optical band-gap of 3.17 eV. As synthesized PAACeO2 Nps effectively catalysed the decomposition of hydrogen peroxide (H2O2) into hydroxyl radicals. Then terephthalic acid was oxidized by hydroxyl radical to form a highly fluorescent product. Under optimized conditions, the linear range for determination of hydrogen peroxide was 0.01 - 0.2 mM with a limit of detection (LOD) of 1.2 μM. Conclusion: The proposed method is ideally suited for the sensing of H2O2 at a low cost and this detection system enabled the sensing of analytes (sugars), which can enzymatically generate hydrogen peroxide.

Background: Optical properties of citrate capped dodecahedral gold nanoparticles have immense applications in a large variety of fields. The interband transition has a role in determining the optical behaviour of gold nanoparticles. Interband transition in citrate capped colloidal gold nanoparticles in the size range above ~5 nm has been left unattended for a long time. Objective: The present work is aimed at studying interband transition in citrate capped colloidal gold nanoparticles of size between ~5 nm and several tens of nanometres. Methods: Turkevich method and modified Brust method were used to prepare citrate capped colloidal gold nanoparticles. Transmission electron microscopy was used to determine their size and shape and their formation was explained with simulated figure obtained by Gnuplot programming. Interband transition was studied with the help of UV-Visible absorption spectroscopy. Results: Dodecahedral citrate capped colloidal gold nanoparticles of mean diameters 31.5 nm, 12.87 nm and 4.69 nm with LSPR peak positions at 528 nm, 524 nm and 509 nm were prepared. The interband peak of nanoparticles of all three sizes was found to be located at about 260 nm. Conclusion: Interband transition between Fermi level and 5d bands of the larger density of states in citrate capped dodecahedral colloidal gold nanoparticles of size above ~5nm leads to absorbance peak at ~260 nm, indicating a gap of ~4.77 eV between the Fermi level and closely spaced 5d bands. For smaller nanoparticles, absorption due to interband transition becomes more prominent relative to surface plasmon resonance absorption.

Background: The production of hydrogen from catalytic reforming ethanol has attracted wide attention, which provides a promising way to replace fossil fuels with sustainable energy carriers. Methods: In this work, the Ce1-xLaxO2-δ solid solution (CL) supported Rh catalysts (nRh/CL, n = 0.5, 1 and 2 wt.%) were prepared by a traditional impregnation method with a variation of Rh loading. The different interface structure of nRh/CL catalysts and their catalytic performance in oxidative steam reforming (OSR) reaction were investigated. Results: Rh was loaded by the traditional impregnation method, and ethanol conversion and H2 yield declined in the order of 1%Rh/CL > 2%Rh/CL > 0.5%Rh/CL. Conclusion: The supports of the nRh/CL catalysts were confirmed to be Ce1-xLaxO2-δ solid solution, but only for the 1%Rh/CL catalyst, the Rh species were well-dispersed on the support and formed a Rh2O3//Ce1-xLaxO2-δ interface structure. The super-cell structure of Rh3+-O-RE3/4+ (RE = Ce, La) on the surface of 0.5%Rh/CL catalyst and the formation of interfacial Ce1-x-yLaxRhyO2-δ solid solution for 2%Rh/CL catalyst had effects on the self-activation of the nRh/CL catalysts. The typical lattice expansion of Ce1-xLaxO2-δ solid solution lowered the energy for migration. And the excellent hydrogen and oxygen mobility at the Rh//Ce1-xLaxO2-δ interface for 1%Rh/CL catalyst guaranteed the good catalytic performance for OSR at low temperature.

Background: Formaldehyde (HCOH) is the most abundant airborne carbonyl indoor volatile organic compound (VOC), which is well-known to cause serious health effects such as respiratory system disease, immune system disorders, and central nervous system damage. Methods: The interaction between HCOH and intrinsic, congeners of Au, Ag, Cu-doped SWCNTs were investigated by density functional theory (DFT) to evaluate the detection of formaldehyde. Results: The results demonstrated that the less adsorption on the surface of intrinsic SWCNT, an HCOH molecule tended to be chemisorbed to the Au, Ag, and Cu atoms of doped SWCNT with larger binding energy of 0.4-0.8 eV and smaller binding distance of 1.9-2.3 Å. Furthermore, charge transfer and density of state studies indicated tha t the electronic properties changed evidently in the most stable HCOH-doped SWCNT systems, mainly at the region of -5.5 to -4.5 eV and Fermi level. Conclusion: More importantly, the adsorption of HCOH affected the electronic conductance of doped SWCNT. It is expected that the results obtained in this study could provide a useful theoretical guidance for the investigation of molecular films interface bonding and design of HCOH sensing devices.