Nanoscience & Nanotechnology-Asia - Volume 10, Issue 3, 2020

In recent time, green synthesis of metal nanoparticles is the latest developing technology and received prodigious interest because it is easy, environmentally pristine, non-fouling, antitoxic, and lowcost approach. Green route of biogenic synthesis of metal nanoparticles via microbes such as bacteria, fungi, virus, yeast and algae has the potential to deliver sustainable and enviro safe protocol. Green synthesized metal nanoparticles are the most optimistic and novel agent for various catalytic and biological activities as antibacterial, antiviral, anticancer etc. without any toxic effects. Here, we reviewed algae-mediated green synthesis of metal and metal oxide nanoparticles and their biological activity. Algae are photoautotrophic, eukaryotic, aquatic, unicellular or multicellular organisms. Algae commonly used for biosynthesis because they grow rapidly, their biomass growth on average ten times faster than higher plants and easy to handle experiments with algal species. Different algal strains such as red, green and brown algae are using for the green synthesis of metal nanoparticles. Algae contain bioactive molecules and secondary metabolites that act as reducing, capping and stabilizing agent for manufacturing in nanoparticles. Biogenically synthesized metal and metal oxide nanoparticles characterized by different techniques such as UV-visible spectroscopy, SEM (scanning electron microscopy), HR-TEM (high-resolution transmission electron microscopy), XRD (X-ray diffraction), TGA (thermogravimetric analysis), DLS (dynamic light scattering) zeta potential and exhibited biological activity. In future, research algal production of metal nanoparticles can be explored by the use of different microalgae and their applications in different areas such as biological activity, catalytic activity in the synthesis of organic compounds, medical diagnose and synthesis of nanocomposite, lipid nanoparticles and antibiofilm.

Extensive attempts have been made to decipher the problem associated with the solubility of drugs for maximizing bioavailability at targeted sites. More than 40% NCEs (new chemical entities) emerged through modern technology like high throughput screening, combinatorial chemistry, computer-aided drug design etc. and the drug discovery process has been dramatically accelerated. Fabrication of materials into the nanodimension changes their physical properties which depicts a vivid shift from lab scale optimization studies to scale up focused studies. In addition, this comprehensive review covers physics behind the drug nanocrystals and their properties, different technologies and methods of drug nanocrystal preparation and its stabilization along with theapplication of nanocrystals. This review also covers factors affecting nanoformulations, post-production processing and future prospects.

Background: In recent years, the Design of Experiments (DOE) is used for removing pollutant from wastewater by nano-adsorbent. Some methods are Taguchi, Response Surface Methodology (RSM) and factorial design. The aim of this paper is to review different used methods of DOE in removing pollutant to suggest some notations to scholars. Methods: The reviewed papers were searched in Google Scholar, Scopus, and Web of Science randomly and categorized based on DOE methods. Results: Number of factors and responses in DOE for removing pollutants from wastewater are between 2-6 and 1-4, respectively. There are several computer software programs that provide simple use of these methods, such as Qualitek, Design Expert, Minitab, R and Matlab Programming. All models have a coefficient of determination R-sq more than 0.9. Conclusion: All the mentioned methods are appropriate because of the high R-sq value. Since the largest number of runs are used in RSM, it is not suitable for the experiments which are conducted by expensive materials and process. Furthermore, Design Expert and Minitab are the most popular software used by scholars in DOE methods for the removal of pollutant.

Alzheimer’s Disease (AD) is one of the most common forms of dementia affecting over 46 million people, according to AD International. Over the past few decades, there has been considerable interest in developing nanomedicines. Using nanocarriers, the therapeutic compound could be delivered to the site of action where it gets accumulated. This accumulation, therefore, reduces the required doses for therapy. Alternatively, using nanocarriers decreases the side effects. Nanotechnology has had a great contribution in developing Drug Delivery Systems (DDS). These DDS could function as reservoirs for sustained drug release or control the pharmacokinetics and biodistribution of the drugs. In the current review, we have collected 38 original research articles using nanotechnology as DDS for the clinically used cholinesterase inhibitor drugs donepezil (DPZ), Rivastigmine (Riv), and galantamine (Gal) used for AD treatment from 2002 to 2017 from Scopus and PubMed databases. Regarding DDS used for DPZ, most of the research in recent years dealt with polymeric nanoparticles (NPs) including Poly-D, L-Lactide-Co-Glycolide (PLGA), and chitosans (CHs), then Liposomes (LPs), nanogels, and natural products, respectively. In terms of Riv most of the research performed was focused on polymeric NPs including PLGA, polylactic acid (PLA), Poly-E-Caprolactone (PCL), poly-alkyl-cyanoacrylates, CH, gelatin and then LPs. The highest application of NPs in regard to Gal was related to modified LPs and polymeric NPs. Polymeric NPs demonstrate safety, higher stability in biological fluids and against enzymatic metabolism, biocompatibility, bioavailability, and improved encapsulation efficacy. LPs, another major delivery system used, demonstrate biocompatibility, ease of surface modification, and amphiphilic nature.

Rapid growth of nanotechnology in various fields like medicine, diagnostics, biotechnology, electronics has gifted the world with products having extraordinary benefits. With increasing use of nanotechnology based products, there is a growing concern about toxicity associated with nanoparticles. Nano-size attributes unique properties to the material due to the increased surface area. But toxic effects associated with nanoparticles are also pronounced. Therefore, research in the field of nanotoxicology is of great importance. Some critical properties of nanoparticles such as chemical composition, size, shape, surface properties, purity are determinants of nanotoxicity. Thus, meticulous characterization of nanoparticles prior to toxicity assessment helps in reducing the toxicity by careful designing of nanoparticles. In vitro assessment of nanotoxicity involves testing on cultured cells whereas in vivo testing involves use of animal models like mice, rats, aquatic frogs etc. Use of predictive models like Zebrafish, Drosophila melanogaster for nanotoxicity research is increased in last few decades. Advanced methods for nanotoxicity assessment involve the use of electrochemical methods which can also give insights about mechanism of nanotoxicity. As the literature in this field is dispersed, this review collates various approaches to give a scheme for nanotoxicity evaluation right from the characterization to toxicity assessment.

Magnetic nanofluids are defined as fluids exhibiting magnetic properties. These fluids are generated by suspending nanoparticles of magnetic nature in any base fluids. Magnetic nanofluids have been a topic of interest for researchers because of their highly useful and manipulatable properties. With the use of these fluids, heat transfer and flow characteristics can be controlled by applying external magnetic fields. This paper reviews recent investigations in the field of magnetic nanofluids with the purpose of assessing the effects of various parameters on their heat transfer and flow characteristics. The objective of this review is to study the research done in this field and understand the level at which this technology stands with all its opportunities and challenges. The review has been classified into experimental and numerical simulation work. Investigations in the presence and absence of magnetic field have been discussed under experimental work. Investigations in the domain of numerical simulation of magnetic nanofluids have been classified into single phase and multiphase analysis. Some novel applications of magnetic nanofluids have also been discussed. It has been concluded that research in the field of magnetic nanofluids is still in the preliminary stages and further experimental and simulation work needs to be done. The physical process needs to be understood with a deeper perspective to create better models for simulation. In spite of the challenges, research in this field of study has given exciting results and it holds vast potential applications.

Background: On decreasing size down to nanoscale, the optical and electronics properties of semiconductors become tunable instead of being constant. Methods: Based on classical and quantum approach, a simple integrated theoretical model is presented without any adjustable parameter to study the size and shape effect on the refractive index, dielectric constant and bang gap of the semiconducting nanowire. The model predicts that with the decrease in the size of the semiconducting nanowire, dielectric constant and refractive index reduces, whereas as band gap enhances. Results: The theory reveals that the behavior exhibited by cylindrical and noncylindrical nanowires differs due to their different shape factors. Conclusion: Agreement of our predicted results with the available experimental and simulated results and with the other theoretical models validates the present work.

Background: The Adder is one of the most prominent building blocks in VLSI circuits and systems. Performance of such systems depends mostly on the performance of the adder cell. The scaling down of devices has been the driving force in technological advances. However, in CMOS technology performance of adder cell decreases as technology node scaled down to deep micron regime. Objective: With the growth of research, new device model has been proposed based on carbon nano tube field effect transistor (CNFET). Therefore, there is a need of full adder cell, which performs sufficiently well in CNFET as well as different CMOS technology nodes. Method: A new low power full adder cell has been proposed with a hybrid XOR/XNOR module by using CNFET, which is also compatible for the CMOS technology nodes. The performance of the adder cell is validated with HSPICE simulation in terms of power, delay and power delay product. It is observed that the proposed adder cell performs better than the CMOS, CPL, TGA, 10 T, 14 T, 24 T, HSPC and Hybrid_FA adder cells. The CNFET full adder is designed in 32 nm CNFET model and to appraise its compatibility with Bulk-Si CMOS technology, 90 nm and 32 nm CMOS technology node is used. Conclusion: The proposed adder is very much suitable for both CMOS and CNFET technology based circuits and systems. To validate the result, simulation has been carried out with Synopsis tool. This full adder will definitely dominate other full adder cells at various technology nodes for VLSI applications.

Background: Gelatin electrospun fibers incorporated with extracted cardamom Essential Oil (EO) were developed and characterized. Materials & Methods: The gelatin solutions were evaluated in terms of conductivity, morphology, fourier transform infrared spectroscopy, and the effect of cardamom EO on the gelatin fibers. Cardamom EO showed significant antioxidant activity with IC50 value of 5 μg/mL. The extract contained several active components including Cyclohexene, 1-methyl-4-(1-methylethylidene) and Eucalyptol (1.8-cineol) as the most abundant components. Results: The images of the scanning electron microscopy revealed formation of nanofibers from gelatin solution with significant entanglement. Furthermore, discrete beads were appeared by increasing the concentrations of cardamom EO in the gelatin fibers. Reduction in conductivity parameter of EO solutions could explain the observed defects. The fourier transform infrared spectra showed the formation of hydrogen bonds in gelatin fibers. The infrared as well as spectrophotometric spectra confirmed that EO was effectively involved in electrospun fibers. Conclusion: In conclusion, gelatin –a natural biopolymer, incorporated with cardamom EO forms smooth fabricated electrospun nanofibers.

Background: Atenolol is a commonly used antihypertensive drug of class III BCS category. It suffers from the problem of poor intestinal absorption or permeability thus low bioavailability. The objective of the present study was to enhance the permeability of atenolol by using a suitable technique, which is economical and devoid of using any organic solvent. Methods: The nanocrystal technology by high-pressure homogenization was chosen for this purpose, which is a less expensive and simple method. In this technique, no organic solvent was used. The study was further aimed to characterize prepared nanocrystals in the solid state by Fourier Transform Infrared Spectroscopy (FTIR), Powder X-Ray Diffraction (PXRD) patterns, particle size, zeta potential, %yield and drug permeation study through isolated goat’s intestine. An in-vivo study was carried out to determine the pharmacokinetic property in comparison to pure drug powder using rats as experimental animals. The formulation design was optimized by a 3(2) factorial design. In these designs, two factors namely surfactant amount (X1) and speed of homogenizer (X2) were evaluated on three dependent variables namely particle size (y1), zeta potential (y2) and production yield (y3). Results: PXRD study indicated the presence of high crystal content in the prepared formulation. These nanocrystal formulations were found with a narrow size range from 125 nm to 652 nm and positive zeta potential of 16-18 mV. Optimized formulations showed almost 90% production yield. Permeability study revealed 90.88% drug release for optimized formulation in comparison to the pure drug (31.22%). The FTIR study also exposed that there was no disturbance in the principal peaks of the pure drug atenolol. This confirmed the integrity of the pure drug and its compatibility with the excipients used. A significant increase in the area under the concentration-time curve Cpmax and MRT for nanocrystals was observed in comparison to the pure drug. The higher values of the determination coefficient (R2) of all three parameters indicated the goodness of fit of the 3(2) factorial model. The factorial analysis also revealed that speed of homogenizer had a bigger effect on particle size (-0.2812), zeta potential (-0.0004) and production yield (0.0192) whereas amount of surfactant had a lesser effect on production yield (-370.4401), zeta potential (-43.3651) as well as particle size (-6169.2601). Conclusion: It is concluded that the selected method of nanocrystal formation and its further optimization by factorial design was effective to increase the solubility, as well as permeability of atenolol. Further, the systematic approach of factorial design provides rational evaluation and prediction of nanocrystals formulation on the selected limited number of smart experimentation.

Background: In this project, the growth and volatile metabolites profiles of Escherichia coli (E. coli ) and Staphylococcus aureus were monitored under the influence of silver base chemical, nanoparticle and ultra-highly diluted compounds. Materials and Methods: The treatments were done for 12000 life cycles using silver nanoparticles (AgNPs) as well as ultra-highly diluted Argentum nitricum (Arg-n). Volatile organic metabolites analysis was performed using gas chromatography mass spectrometry (GC-MS). The results indicated that AgNPs treatment made the bacteria resistant and adapted to growth in the nanoparticle condition. The use of ultra-highly diluted Arg-n initially increased growth but it decreased later. Also, with the continuous usage of these materials, no more bacterial growth was observed. Results: The most important compounds produced by E. coli are Acetophenone, Octyl acetate, Styrene, 1,8-cineole, 4-t-butyl-2-(1-methyl-2-nitroethyl)cyclohexane, hexadecane and 2-Undecanol. The main compounds derived from S. aureus are Acetophenone,1,8-cineole, Benzaldehyde, 2-Hexan-1-ol, Tridecanol, Dimethyl Octenal and tetradecane. Acetophenone and 1,8-cineole were common and produced by both organisms. Conclusion: Based on the origin of the produced volatiles, main volatiles percentage of untreated sample is hydrocarbon (>50%), while bacteria treatments convert the ratio in to aldehydes, ketones and alcohols in the case of AgNPs, (>80%) and aldehydes, ketones and terpenes in the case of Arg-n (>70%).

Objective: The objective of present study was to enhance the potential activities of Quercetin by improving its solubility and dissolution profiles through solid dispersion approach. Method: A three level full factorial design (32) was adopted to study the possible combinations of polyethylene glycol (PEG) 6000 & pluronic F 127 (PF 127). The solid dispersions were prepared by solvent evaporation method and evaluated for percentage yield, drug content, aqueous solubility and drug release. For in vivo evaluations SD4 was incorporated into Carbopol base gel and subjected to anti-inflammatory activity using carrageenan-induced rat paw edema method. Results: SD4 batch with drug to carrier ratio 1:1 showed release of 82.96 ± 1.76 % in 240 min following Higuchi’s model. It was 5.54 fold increment in solubility as compared to quercetin. SD4 batch was further evaluated by FTIR, DSC, PXRD and SEM. The crystallinity was significantly reduced and drug was homogeneously dispersed in the carrier as shown by the results of DSC, PXRD and SEM. The DPPH scavenging assay showed significance in the IC50 value of SD4 as compared to pure quercetin and ascorbic acid when subjected to one way ANOVA at 0.05 level of significance (P<0.0001). In vivo anti-inflammatory study showed 78.17 ± 0.156 % inhibition of edema by SD4 and 58.64 ± 0.640 % by pure quercetin which is significantly lower (P<0.05). Conclusion: These findings demonstrate that the solid dispersion of quercetin shows increased solubility, dissolution profile, drug release and significant potential in enhancing the antiinflammatory activity of drug.

Introduction: Copolymer PBB-T with benzo[1,2-d:4,5-d']bis(thiazole) (BBT) as the accepting unit and benzodithiophene (BDT) as the donor unit is a promising candidate for highperformance non-fullerene polymer solar cells (PSCs). So far optical and dielectric constants of the PBB-T are not fully known. Method: PBB-T was synthesized and thin films of PBB-T were prepared. By using the Kramers-Kronig relations and the transmission spectra of the PBB-T films, the optical and dielectric constants, including in absorption coefficient (α(λ)), extinction coefficient (Κ(λ)), refractive index (n(λ)), dielectric constant (ε1(λ),ε2(λ)), band gap (Eg) and mobility of the PBB-T films were calculated and analyzed. Result: At 500 nm, α, Κ, n, ε1 and ε2 are 1.65x105 cm-1, 0.46, 1.8163, 3.0 and 1.65 respectively. Eg is 2.111 eV. The hole mobility of PBB-T are 2.41x10-5 cm2 V-1 s-1 and 1.71x10-4 cm2 V-1 s-1 for the as-cast film and for the solvent vapor annealed film respectively. The results show that these optical and dielectric constants of the PBB-T films are almost independent on the thicknesses of the films, indicating our results are reliable. The features of the optical and dielectric constants show the PBB-T films are very promising candidates for high-performance non-fullerene PSCs and potential cut-off filter only permitting red and near-infrared light passing. Conclusion: These results are significant for designing optoelectronic devices related to the PBBT thin films.

Background: The knowledge of parameter estimation for interatomic potentials is useful in the computation of the vibrational structure of van der Waals molecules. Methods: On the estimation of the Generalized Morse and Classical Lennard-Jones potential energy functions, complex conjugates eigenvalues may be obtained. Different approaches can be used to solve this resulting problem. A method that uses the objective least squares function method to estimate parameters of the interatomic potentials is employed. Results: Numerical simulation of the systems using metal atoms yields complex conjugates eigenvalues at some initial point. Conclusion: Other approaches of solving the complex conjugates eigenvalues problem are discussed comprehensively.

A bottom-up-then-up-down route is proposed to construct graphene-ZnS nanoplates (GZnS NP). Graphene-ZnS with hierarchical structure (G-ZnS HS) is first prepared by a “bottom-up” route, and then is transferred to ZnS nanoplates through an “up-down” route by annealing at low temperature. Photocatalytic activity is investigated and the formation mechanism of G-ZnS NP is proposed. This work provides an effective method for large-scale synthesis of graphene-based two-dimensional nanostructures.