Micro and Nanosystems - Volume 14, Issue 1, 2022

Background: Transdermal drug delivery is considered a better alternative to oral administration of drugs like proteins or peptides that are susceptible to extensive degradation via first pass metabolism. This delivery route also shows high patient compliance due to no use of painful injections. Conventional delivery systems like creams and gel show poor skin permeation and high dosing frequency. Objective: The objective of this work was to investigate the role of highly advanced micro and nanocarrier systems like invasomes, transfersomes, transethosomes, oleic acid vesicles, and cubosomes for transdermal drug delivery exploring literature survey. Methods: Literature survey for these advanced micro and nanocarrier systems was carried out using search engines like Pubmed and Google scholar. Results: Results of literature investigations revealed that advanced micro and nanocarrier systems discussed earlier have the caliber to enhance skin permeation of various bioactives, show sustain release, and target particular areas of skin better compared to old nanocarriers like liposomes. Conclusion: The present review concludes that advanced micro and nanocarrier systems like invasomes, transfersomes, transethosomes, oleic acid vesicles, and cubosomes are better alternatives for transdermal delivery of therapeutic agents compared to old nanocarriers like liposomes and conventional delivery systems like creams and gels.

The objective of the present article is to provide an insight into the toxicity aspects of nanoparticles on health and the ecosystem, along with risk assessment and monitoring. After a detailed screening of various research reports from peer-reviewed journals, books, and research news, the article was prepared. Nanotechnology's various significant advantages over conventional technologies have been explored for diverse research and commercial needs, such as cosmetics, medical, pharmaceuticals, biotechnology, electronics, catalysts, and robotics. However, nanotechnology has several challenging elements for health, environment, society, economic growth, and unpredictable consequences due to its unknown nature, which needs to be identified. Therefore, in this review, an attempt has been made to cover the two most important aspects of the toxicity of nanoparticles, i.e., influence on health and the ecosystem. The health hazards to various organs, especially lungs, gastro-intestinal tract and dermis, and aquatic organisms, have been elaborated. Furthermore, various ecotoxicological aspects, including mechanism of ecotoxicity, ecotoxicological challenges, and solutions to be undertaken by ecotoxicologists, are discussed. Finally, risk assessments related to the approaches that can be used for the optimization of nanotechnology are also mentioned. It is high time that nanotechnology gets reconsideration and uncompromising attention at the public and private level regarding its use, handling, storage, proper treatment, and disposal. Also, risk analysis and establishment of regulatory guidelines for the optimization and safe practice of nanotechnology for humans less harmful to the environment are recommended.

Nowadays, the internet has reached every aspect of our day-to-day life. The idea of cryptography is to provide security. It is an encryption technique used for network security when different networks are interconnected and become vulnerable to attacks and intrusions. Different algorithms, like DES, 3-DES, Modified DES, RSA, and Modified RSA algorithms for encryption, have been reported. In this paper, a hybrid cryptosystem which is the combination of the traditional DES and RSA has been discussed. The performance analysis, such as the chi-squared test and then frequency analysis of the hybrid algorithm have been discussed in this article to show the novelty of the combined DES and RSA work, and a comparative study has been performed with the traditional DES and RSA techniques. The chi-squared methodology is a statistical way of evaluating the quality of ciphertext. If the ciphertext needs to be strong then a high value of chi-squared is desired.

Background: Great attention has been paid to the environmental pollution by organic dyes, which are difficult to be degraded in the natural environment and have been an unavoidable and urgent global problem. It is essential to develop green wastewater treatment technology with high removal efficiency and low-cost for protecting the surrounding and human health. Objective: The aim of the research is to synthesize lithium bismuthate/bismuth oxide microspheres with good photocatalytic performance for the removal of gentian violet (GV). Methods: Lithium bismuthate/bismuth oxide microspheres were successfully prepared by a sodium ligninsulfonate-assisted hydrothermal synthesis route. The lithium bismuthate/bismuth oxide microspheres were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FTIR), and solid UV-vis diffuse reflectance spectrum. Results: XRD pattern and SEM observation show that the lithium bismuthate/bismuth oxide microspheres are composed of cubic LiBi12O18.50 and monoclinic Bi2O3 with a diameter of 250 nm-1 μm. Irregular microscale and nanoscale particles are formed under low hydrothermal temperature, low sodium ligninsulfonate concentration, and short duration time. By increasing the sodium ligninsulfonate concentration, hydrothermal temperature, and duration time, irregular particles are transferred into microspheres. Lithium bismuthate/bismuth oxide microspheres possess a band gap energy of 1.85 eV, suggesting good visible light absorption ability. The photocatalytic removal ability for GV is enhanced by prolonging light irradiation time and microspheres dosage. GV solution with the concentration of 10 mg•L-1 is able to be totally degraded by 10 mg lithium bismuthate/bismuth oxide microspheres in 10 mL GV solution under solar light irradiation for 6 h. Conclusion: The lithium bismuthate/bismuth oxide microspheres show good photocatalytic removal ability toward GV in wastewater under solar light irradiation.

Background: The widespread use of iron nanopowders is connected with a wide range of characteristics such as size, magnetic characteristics and high surface area and that is why many researches present its different applications in the literature. Objective: The work studies the influence of the conditions for the iron wire electrical explosion on the course of the explosion process and the dispersed composition of the resulting metal nanopowder. Methods: Experiments on the electrical explosion of iron wires were carried out in the laboratory setup with the different initial conditions of the electrical explosion of the iron wire. Results: The influence of the initial wire electrical explosion conditions on the explosion regime, the specific energy input into the conductor, and the specific energy released in the arc stage of discharge are definitely determined. The empirical equations for the calculation of the initial wire electrical explosion conditions for providing the critical explosion in the argon medium at a pressure of 2·10⁵ Pa, were defined. It has been established that for the synthesis of iron nanopowders with a narrow particle size distribution, it is preferable to use modes with a high level of the energy released in the arc stage of the discharge. Conclusion: It was found that disabling the arc stage of the discharge during EEW leads to the decrease of the average surface particle size by 50%.

Aims: Al7075 is a well-defined alloy for its excellent physical and mechanical behavior, such as high strength, toughness, and low density. To reach the expectations of the automobile and aerospace applications, the properties of Al7075 alloy have to be improved by reinforcing nano-sized Al2O3 particles. Objectives: Synthesis and characterization of the Al7075 alloy reinforced with Al2O3 nano particles for different structural engineering applications. Methods: In this present work, nano-sized Al2O3 particles were added and dispersed homogeneously using a stir casting technique. AA7076/Al2O3 composites were prepared by varying wt.% percent of Al2O3 reinforcement particles (0.75, 1, 1.25, 1.5. 1.75 and 2 wt.% (weight-percentage)). Results: The SEM micrographs reveal the homogeneous distribution of Al2O3 reinforcements along the grain boundaries of the Al7075 matrix material. The experimental test results showed that the addition of Al2O3 reinforcements and the mechanical properties of the Al7075/Al2O3 composite improved as compared to the Al7075 matrix material. Conclusion: The composite with 1.5 wt.% Al2O3 showed higher strength and hardness as compared to other reinforcements.

Aim: Aim of this study is to find the effect of the current collector on the performance of flexible energy storage devices based on surface modified organic-inorganic composite. Objective: As a part of our pursuit to develop flexible supercapacitive electrodes, we recently reported the fabrication of an electrode from an organic-inorganic composite slurry of surface functionalized fullerene and nickel hydroxide coated onto a copper sheet substrate using simple doctor blade method. We reported that the electrodes deliver specific energy and specific power of 661.5 Wh/kg and 8.8 KW/kg, respectively, and a specific capacitance of 675 Fg⁻¹, which showed excellent cycling stabilities. In an effort to search for various combinatorial combinations of the composite and the substrate, in lieu of copper, in the present study, we incorporate nickel sheet as the current collector. Methods: The structure and composition of the binder-free, flexible, super capacitive electrodes were characterized using XRD, TEM, FTIR, XPS, BET, Raman Spectroscopy, and their electrochemical properties were characterized using cyclic voltammetry, galvanostatic charge-discharge measurements, chronoamperommetry and impedance spectroscopy. Results: The as-prepared films stuck readily onto the substrate without the need for any binder material, exhibited remarkable flexibility, and were proven to be crack-free when subjected to repeated bending and twisting. The developed flexible, super capacitive electrodes deliver a specific capacitance of 296 F g⁻¹, maximum energy density of 82.2 Wh kg⁻¹, and a maximum power density of 1056 W kg⁻¹. The device retains 91.2 % of its capacitance when subjected to 1000 charge-discharge cycles. Conclusion: Our observations indicate that copper is the better choice as the current collector, which can be ascribed to the better electrical conductivity of copper compared to nickel. We conclude that the poor electrical conductivity of nickel sheet compared to copper substrate make the bottleneck for the performance of electrodes made using nickel substrate. To recapitulate, a judicious choice of a current collector with high electrical conductivity along with a suitable surface modification strategy to form a composite in an amorphous form that forms smooth slurry are vital to the fabrication of binder-free, flexible supercapacitive devices.

Background: Electrolyte is an essential constituent of a dye-sensitized solar cell (DSSC) as it mediates charge transport and regenerates the oxidized dye. Iodide/triiodide (I-/I^3-) based electrolytes are the ones widely being used in DSSCs. These types of electrolytes are usually made by dissolving high concentrations of triiodide and polyiodide species in solvents, such as acetonitrile and methoxypropionitrile. These solvents face evaporation issues and lead to stability problems, which reduces the life span of the DSSC. For solving these issues, various types of electrolytes, such as ionic liquids and gelated liquid electrolytes, have been used to replace conventional volatile electrolytes. Objective: To solve the solvent evaporation issue and the electrical resistance rise, we aim to synthesis a non-volatile electrolyte with excellent open-circuit voltage and stability. Methods: A new genre of nonvolatile Co(II)/Co(III) redox electrolyte was synthesized by the reaction of tris(2-(1H-pyrazol-1-yl)pyridine)cobalt(II) and tris(2-(1H-pyrazol-1-yl)pyridine) cobalt(III) with 2,4,6-tris(dodecyloxy)benzaldehyde. As a proof-of-principle experiment, a DSSC was fabricated using the as-synthesized electrolyte, N-719 dye as the light harvester, and TiO2 as the photoanode, and their performances were analyzed in room light conditions. Results: The DSSCs deliver a remarkable power conversion efficiency of 22.1%, an open circuit voltage of 1 V, and a power output of 88.5 μW cm^–2 at 1000 lux, under illumination from a Deltron LED light. Conclusion: Cobalt-based non-volatile electrolytes are efficient candidates that can replace the conventional volatile electrolytes in DSSCs. Further research into this new type of electrolyte could pave ways to deliver high open-circuit voltage as well as good current density with high stability.

Aim: The aim of this work was the preparation of the model Magneto-Rheological (MR) fluids to be used under the effect of an applied magnetic field operated under very low power requirement for the purpose of vibration reduction in automotive damper. Background: Magneto-rheological fluids are non-Newtonian fluids, which consist of magnetic particles scattered in a base liquid – a matter that can change its characteristics when applying the magnetic field. From the previous researches, magneto-rheological fluids have different properties according to the preparation accuracy, ingredients, particle size and shape, type of carrier fluids, and stabilizer. Also, the response of magneto-rheological fluids to the magnetic flux varied. Methods: A specimen of MR fluid is prepared using four different dynamic viscosities base fluids. Silicone oil JETTA (50 mpa.s, 100 mpa.s, 150 mpa.s, and 200 mpa.s) is mixed with high purity spherical shape particles of Carbonyl Iron (CI). ABRO liquid white lithium grease is added to the specimen, and its effect is determined. Results: The presence of additives has no effect on the magnetic behavior, but it increases the dynamic viscosity, especially in the presence of the external magnetic field, which is considered as a stabilizing factor. Conclusion: Adding the white lithium grease as a stabilizer delays the sedimentation of the prepared sample by 1023%. The lowest sample in sedimentation rate has the highest viscosity, which satisfies 2.7% in 24 hours, but it shows a negative effect on the magneto-rheological properties, which leads to unstable viscosity readings due to MR fluid agglutination. Working temperature is a critical parameter that can affect the behavior of MR fluid; the viscosity of MR fluid under the effect of the magnetic field is inversely proportional to the working temperature. Sample DELTA is the most promising for the application in automotive dampers, which is used to decrease vehicle vibration.