Current Nanoscience - Volume 15, Issue 5, 2019

Background: The high molecular weight and increasing lipophilicity drug face many problems starting from the drug development to formulation and conduction of pharmacological, toxicological and pharmacokinetic studies to its biological application. To overcome this problem, a different formulation of nano-sized drugs was developed recently. The use of Solid lipid nanoparticles (SLNs) and Nanostructured lipid carriers (NLCs) offers new insight into the formulation of the poorly soluble drug. Objective: The study aimed to investigate the literature with regard to the development of SLNs and NLCs for lipid-based nano drug delivery of poorly soluble drugs, with a view to identifying the factors influencing the optimization of the formulation of SLNs and NLCs and strategies to decrease the use of organic solvent during the preparation. Results: This review highlights the simple and easily scaled-up novel lipid nanoparticles (SLNs and NLCs) and their factors to be considered in the formulation for the proper selection of excipients. Also, this review summarizes the research findings reported by the different researchers regarding the principle formulation components, different preparation techniques, characterization, and toxicology of lipid nanoparticles. Conclusion: The SLNs/NLCs make this drug delivery system as one of the promising delivery systems, and safe colloidal lipid carriers for the delivery of poorly soluble drug and will be a solution to the formulation scientist for the solubility and permeability problem associated with the drugs to assure its good bioavailability.

Background: Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. Thanks to their electrical, mechanical and optical properties, they have been widely used for different pharmaceutical, biological and biomedical applications. To understand the biofate of the CNTs in the body, their pharmacokinetic properties should be revealed appropriately. Objective: To review the available literature, regarding the different pharmacokinetic properties including absorption, distribution, metabolism and elimination of the functionalized CNTs. Results: Surface coating or functionalizing the CNTs has huge effects on their pharmacokinetics, ADME properties and also their biodistribution profile. During the metabolism, CNTs could be destroyed directly or their surface functional groups might be removed. Both biliary and renal pathways are known for CNTs elimination. Conclusion: Additional optimization on the CNTs formulation is required to enhance their absorption and bioavailability. Besides, regarding the increased scientific attention towards the CNTs toxicity, it could be suggested that determining the bioavailability of CNTs is a critical parameter to determine the CNTs safety.

The excessive use of nitrogen and phosphorous fertilizers led to environmental pollution and serious health issues. Nanotechnology may solve such a type of problems by providing nanomaterials of high performance. Here, we reviewed the beneficial effects of some different nanoparticles on the growth of different parts of different plants belonging to 14 different families. Nanoparticles such as CNT, Ag-NPs, TiO2-NPs, Au-NPs, S-NPs, Ag-NPs+ Magnetic field-NPs, ZnO-NPs, Fe-NPs, SiO2-NPs, RA-NPs, Zinc-NPs, Silica-NPs, Apatite-NPs, CeO2-NPs, Cu-NPs, CaCO3-NPs, Chitosan- NKP-NPs and Carbon nono-tube coated NKP+ Chitosan NPK-NPs show better growth enhancement effect on different parts of plants and crop production when used in proper concentration. We find that the most favorable effect of NPs was on, chlorophyll contents, root and shoot length followed by proteins contents and plant biomass.

In this paper, we review a procedure to study the effects of temperature in the design of A/D circuits based on CNTFETs. At first, we briefly describe a compact model, already proposed by us, in which the temperature variation in the drain current equation and in energy band gap is considered. Then, the effects of temperature variations in the design of analog circuits, such as a cascode current sink mirror and an Operational Transconductance Amplifier (OTA), and in the design of digital circuits including in particular NAND and NOR logic gates, are illustrated and widely discussed.

Background: The nanomechanical properties of Zr50Cu50 metallic glass under tension are studied. The effects of temperature and alloy composition are investigated in terms of atomic trajectories, slip vectors, stress-strain curve, and radial distribution function. Methods: The molecular dynamics simulations based on the many-body tight-binding potential are applied to analyze the nanomechanical properties of metallic glass under tension. Results: The mechanical properties of the metallic glass are sensitive to temperature and alloy composition. Under tensile deformation, the stress increases with increasing temperature and Zr content in the alloys. At higher temperatures, the alloy atoms have high slip vectors, and plasticity becomes more homogeneous due to a better flow ability of atoms. Conclusion: The alloys with higher Zr content have larger mechanical strengths. The alloys with higher Cu content have more stable structures.

Background: The electrical and optical properties of nanoparticle-based devices depend on the shape, dimension and uniformity of these particles. Methods: In this work, we fabricated ordered Au nanodots using electron beam lithography and thermal evaporation. Au nanodot diameter and circularity varied with a changed exposure dose and resist thickness. Electron beam dose ranged from 5 fC to 200 fC for single dot patterns. Commonly used PMMA thin films of thicknesses 60 nm and 100 nm coated samples were used for investigating the resist thickness dependency with varying dose exposure. Results: The analyses of patterns show that the diameter and circularity of the Au nanodots ranged from smaller to larger diameters and from lower to higher circularities with increasing dose and resist thickness. Conclusion: The distributions of the nanodot diameter began to show Gaussian behavior at larger electron doses. Besides, single circularity value became dominant up to the medium doses and then a homogeneous distribution was observed with the increasing dose.

Background: Formaldehyde belongs to important pollutant and is usually found in liquid environment, such as juices, beer, cleaning products and biological fluid of the human. The electrochemical sensors using glassy carbon electrode (GCE) modified with polyaniline/Zn bismuthate nanocomposites can effectively detect formaldehyde with broad linear range and good reproducibility. Methods: Polyaniline/Zn bismuthate nanocomposites were prepared by in-situ aniline polymerizing route in aqueous solution. The structure and morphologies of the nanocomposites were analyzed by X-ray diffraction (XRD) and transmission electron microscopy. The electrochemical performance for formaldehyde detection has been investigated by cyclic voltammetry (CV) method using polyaniline/ Zn bismuthate nanocomposites modified GCE. Results: XRD shows that ZnBi38O58 phase exists in the nanocomposites. Amorphous polyaniline attaches to the surface of the Zn bismuthate nanorods. The 20wt.% polyaniline/Zn bismuthate nanocomposites modified GCE shows an irreversible cyclic voltammetry (CV) peak at –0.06 V. The peak current increases sharply with increased scan rate, formaldehyde concentration and acidity. The electrochemical response dependences including the linear range, detection limit were analyzed. 20wt.% polyaniline/Zn bismuthate nanocomposites modified GCE shows low detection limit of 0.0095 μM and wide linear range of 0.00001-2 mM. The detection limit for formaldehyde decreases from 0.028 μM to 0.0075 μM with the increase in the polyaniline content from 10wt.% to 40wt.%. Conclusion: The low detection limit and wide linear range make the nanocomposites modified GCE valuable for sensor application. Polyaniline/Zn bismuthate nanocomposites are identified as the prominent electrode materials for sensitive formaldehyde detection.

Background: Energy crisis is a vital issue worldwide and it will be increased tremendously in future. Alternative energy sources have been sought for the betterment of the future world. Solar energy is an alternative energy resource with plenty of opportunities. To make user- friendly and cheaper solar cells, dye-sensitized solar cells are tried to develop in this aspect. Objective: Single dye is not good enough to capture a wide range of solar light. The blending of different dyes is an alternative approach to harvest a wider range of solar lights on solar cells. Here, N719 and IR dyes were utilized to get UV-VIS and NIR ranges of solar lights in dye-sensitized solar cells. Methods: Dye-sensitized solar cells (DSSCs) were fabricated by using mixed dyes with various combinations of N719 (dye A) and IR dyes (dye B). The mixed dyes solutions were adsorbed on titanium dioxide (TiO2) and revealed significant light absorption & photosensitization compared with the individual dye solutions. The DSSCs fabricated with more percentage of IR dyes exhibited the best sensitization and broader spectrum. Results: The light absorption spectrum of the blended dyes solutions was confined peaks resultant of both N719 and IR dyes. The maximum efficiencies of 7.91% and 7.77% were obtained with 70% and 80% of IR dyes, respectively. Conclusion: Both N719 and IR mixed dyes solar cells were fabricated successfully for the first time. The relevant reasons behind the working of N719 and IR mixed dyes solar cells have been discussed. It was also noted that only IR dyes sensitized cells did not function under the simulated sunlight.

Background: Non-precious metal based catalysts have become a hot research material due to their easy availability, low cost and outstanding electrochemical performance. Among them, carbon-based materials like carbon nanotubes and porous carbon with their own characteristics are especially favored by researchers in the field of catalyzing oxygen reduction. Therefore, rational construction of combining porous carbon with carbon nanotubes attracts great research attention on the object to utilize the excellent porosity, large specific surface area of porous carbon and the good electronic conductivity, high stability of carbon nanotubes to catalyze oxygen reduction. In this work, we synthesized two catalysts with different structure of coating carbon nanotubes with porous carbon by paralyzing a mixture of pre-prepared porous carbon, Co3O4 nanoparticles and melamine/ glucosamine hydrochloride. Then, the composites were applied to fuel cells as cathodic oxygen reduction reaction catalysts, which both exhibited good onset potential and excellent stability. Methods: Briefly, the porous carbon was prepared by heating the mixture of glucosamine hydrochloride and Co(NO3)2·6H2O under N2 flowing. Co3O4 nanoparticles were prepared by pyrolyzing cobalt nitrate-impregnated cotton wool. The CNTs/PC was synthesized by pyrolyzing the mixture of porous carbon, Co3O4 nanoparticles and melamine. The CNTs@PC was synthesized by pyrolyzing the mixture of porous carbon, Co3O4 nanoparticles and glucosamine hydrochloride. The cyclic voltammetry, liner sweep voltammetry and chronoamperometry measurements were analyzed to obtained the catalysis performance for oxygen reduction. Results: Through the rational design of catalyst structure, porous carbon and carbon nanotubes with different structures were constructed to expose more active sites on the surface of the sample. As a result, the onset potential of CNTs/PC and CNTs@PC are all at 0.9 V. After 20,000s chronoamperometry measurement, the current holding rate of CNTs/PC reached 95%, CNTs@PC was 94%, while Pt/C was only 77%. This shows that the prepared catalysts possess outstanding stability compared to Pt/C. Conclusion: In this work, we synthesized two catalysts with different structure by paralyzing a mixture of pre-prepared porous carbon, Co3O4 nanoparticles and melamine/glucosamine hydrochloride, growing carbon nanotubes on the surface (CNTs/PC) and inside (CNTs@PC) of the porous carbon framework. The catalytic property of prepared CNTs/PC and CNTs@PC all possess good onset potential and excellent stability toward ORR. Therefore, a reasonable design of the catalyst structure is required to expose more active sites on the sample surface.

Background: Nanoclays incorporated in dental resins have been previously investigated. However, limited reports are associated with nanoclays that exhibit high functionality. Objective: The aim of this study was the targeted synthesis and characterization of organomodified nanoclays with methacrylic groups suitable for incorporation in dental nanocomposite resins. Methods: Quaternary ammonium methacrylates were synthesized and characterized by means of proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Consequently, they were inserted into the interlayer space of nanoclay through a cation exchange reaction, while silane was also used for simultaneous surface modification. The produced organomodified nanoclays were characterized by means of X-ray diffraction, Fourier-transform infrared spectroscopy and thermogravimetric analysis. Results: Fourier-transform infrared spectra confirmed the successful synthesis of the quaternary ammonium methacrylates. X-ray diffraction analysis showed that organoclays exhibited higher d001- values (up to 1.78 nm) compared to raw nanoclay (1.37 nm), indicating an accomplished intercalation in each case. X-ray diffraction spectra mainly disclosed the presence of methacrylic functional groups in all nanoclays. Thermogravimetric analysis curves verified the different thermal stability of organoclays due to the diversity of their organic modifiers. Conclusion: The experimental results showed that nanoclay was successfully modified with ammonium methacrylates and silane. he combination of X-ray diffraction and thermogravimetric analysis data revealed a high degree of intercalation and methacrylated organic loading as well. These phenomena may favor a good dispersion and high polymerization degree of nanoclays with dental resin monomers, rendering them potentially useful materials for the development of advanced dental nanocomposites resins.

Background: Flower-shaped micro/nanostructures containing adsorbent and antimicrobial agent within the same particle are a new generation of materials with considerable potential in the field of biomedicine. Objective: Flower-shaped micro/nanostructures were fabricated by the reaction of Al/Cu, Al/Fe and Al/Zn bimetallic nanoparticles with water. Al/Cu, Al/Fe and Al/Zn nanoparticles were produced by the simultaneous electric explosion of a pair of the corresponding metal twisted wires (aluminum and copper, aluminum and iron or aluminum and zinc) in argon atmosphere. The synthesized bimetallic nanoparticles interact with water to form micro/nanostructures with flower-shaped morphology. Methods: The properties of the obtained products were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, adsorption of nitrogen (BET method) and electrophoretic mobility. The antimicrobial activity of the micro/nanostructures against the bacteria Escherichia coli was studied. The toxicity of these micro/ nanostructures against the L 929 mouse fibroblast cell line was investigated. Results: The micro/nanostructures showed biocidal activity against gram-negative bacteria. The micro/nanostructures AlOOH(Fe) have a low toxicity and can be used for drug delivery. Conclusion: The micro/nanostructures with flower-shaped are good candidates for medical applications as antimicrobial and healing dressing components.

Background: Immunotherapy involving dendritic cells (DC) has been used to treat cancer with satisfactory results. The generation of mature dendritic cells derived from monocytes, however, is expensive because of the use of cytokines. Objective: To reduce DC therapy costs, it is important to evaluate lower-cost materials capable of inducing dendritic cell maturation; for this purpose, we synthetized chitosan nanoparticles. Methods: Chitosan nanoparticles were synthetized by ionic gelation and characterized using dynamic light scattering, laser Doppler electrophoresis, transmission electron microscopy and infrared spectrum. Endotoxin levels were determined by Limulus amoebocyte lysate. The biological effect was evaluated by microscopy, immunophenotypification, cellular viability and phagocytosis assays. Results: We synthetized endotoxin-free chitosan nanoparticles with an average size of 208 nm and semi-spherical morphology. The nanoparticles induced changes in monocyte morphology, surface marker expression and phagocytosis that correlate with those of DC. These preliminary results demonstrate that chitosan nanoparticles can induce monocyte differentiation into immature dendritic cells and, when combined with albumin and keyhole limpet hemocyanin, they can induce dendritic cell maturation. Conclusion: We conclude that chitosan nanoparticles are a suitable alternative for lower-cost DC immunotherapy generation, provided that our results be corroborated in vivo.

Background: In AFM study of cell mechanical properties, the apparent elastic modulus of a cell is affected by many factors, especially the AFM tip geometry, indentation site of the cell, the application of the mathematical model and testing conditions. Methods: In this study, indentation experiments of living cells under different conditions were performed aiming to build an accurate evaluation system of mechanical properties of lung cancer cells based on AFM. Comparisons of the effects of spherical and pyramid AFM tips, Hertz model of semiinfinite and finite thickness, cell nuclear and cytoplasmic indentation regions on the cell apparent elastic modulus were accomplished. Results: Compared with the calculated results by spherical tip, the elastic modulus distribution of non-small lung cancer cells (NSCLC) by pyramid tip was observed to be similar while the absolute values increased obviously, which were more than twice the numerical values by the spherical tip (p<0.05). The apparent elastic modulus values were the overvalued cause of the underestimation of the contact region in pyramidal tip measurement. Two different indentations over nucleus or lamellipodium of NCI-H520 cell and NCI-H1299 cell were analyzed. Consequently, the exact elastic modulus over the nucleus area can be calculated accurately using the semi-infinite Hertz model while the finite thickness Hertz model should be used for elasticity assessment of cell lamellipodium with a small thickness. Conclusion: This evaluation system provides technological support for accurate evaluation of viscoelastic properties of living cancer cells.