Reliable optoelectronic switchable device implementation by CdS nanowires conjugated bent-core liquid crystal matrix

Biosynthesis and antibacterial activity of ZnO nanoparticles usingBuchanania obovatafruit extract and the eutectic-based ionic liquid

The fruit extract ofBuchanania obovataand the eutectic-based ionic liquid were utilized, in an eco-friendly, inexpensive, simple method, for synthesizing zinc oxide nanoparticles (ZnO NPs). The influence of the reducing, capping and stabilizing agents, in both mediums, on the structure, optical, and morphological properties of ZnO NPs was extensively investigated. The surface plasmon resonance peaks were observed at 340 nm and 320 nm for the fruit-based and the eutectic-based ionic liquid mediums, respectively, indicating the formation of ZnO NPs. XRD results confirmed the wurtzite structure of the ZnO NPs, exhibiting hexagonal phases in the diffraction patterns. The SEM and TEM images display that the biosynthesized ZnO NPs exhibit crystalline and hexagonal shape, with an average size of 40 nm for the fruit-based and 25 nm for the eutectic-based ionic liquid. The Brunauer-Emmett-Teller (BET) surface area analysis, revealed a value ∼13 m2g-1for ZnO NPs synthesized using the fruit extract and ∼29 m2g-1for those synthesized using the eutectic-based ionic liquid. The antibacterial activity of the biosynthesized ZnO NPs was assessed against clinically isolated Gram-negative (E. coli) and Gram-positive (S. aureus) bacterial strains using the inhibition zone method. The ZnO NPs produced from the eutectic-based ionic liquids confirmed superior antibacterial activity against bothS. aureusandE. colicompared to those mediated by the utilized fruit extract. At a concentration of 1000, the eutectic-based ionic liquid mediated ZnO NPs displayed a maximum inhibition zone of 16 mm againstS. aureus, while againstE. coli, a maximum inhibition zone of 15 mm was observed using the fruit extract mediated ZnO NPs. The results of this study showed that the biosynthesized ZnO NPs can be utilized as an efficient substitute to the frequently used chemical drugs and covering drug resistance matters resulted from continual usage of chemical drugs by users.

Potential antibacterial, antibiofilm, and photocatalytic performance of gamma-irradiated novel nanocomposite for enhanced disinfection applications with an investigated reaction mechanism

BACKGROUND

Water scarcity is now a global challenge due to the population growth and the limited amount of available potable water. In addition, modern industrialization, and microbial pathogenesis is resulting in water pollution on a large scale.

METHODS

In the present study, reusable Co0.5Ni0.5Fe2O4/SiO2/TiO2 composite matrix was incorporated with CdS NPs to develop an efficient photocatalyst, and antimicrobial agents for wastewater treatment, and disinfection purpose. The antibacterial performance of the gamma-irradiated samples was evaluated against various types of Gram-positive bacteria using ZOI, MIC, antibiofilm, and effect of UV-exposure. Antibacterial reaction mechanism was assessed by bacterial membrane leakage assay, and SEM imaging. In addition, their photocatalytic efficiency was tested against MB cationic dye as a typical water organic pollutant.

RESULTS

Our results showed that, the formed CdS NPs were uniformly distributed onto the surface of the nanocomposite matrix. While, the resulted CdS-based nanocomposite possessed an average particle size of nearly 90.6 nm. The antibacterial performance of the prepared nanocomposite was significantly increased after activation with gamma and UV irradiations. The improved antibacterial performance was mainly due to the synergistic effect of both TiO2 and CdS NPs; whereas, the highest photocatalytic efficiency of MB removal was exhibited in alkaline media due to the electrostatic attraction between the cationic MB and the negatively-charged samples. In addition, the constructed heterojunction enabled better charge separation and increased the lifetime of the photogenerated charge carriers.

CONCLUSION

Our results can pave the way towards the development of efficient photocatalysts for wastewater treatment and promising antibacterial agents for disinfection applications.

Impact of core polarity on smectic B-induced hydrogen bond liquid crystals

The novel series of hydrogen bond liquid crystals were synthesized from the 2-methylglutaric acid (MGA) and 4-alkyloxybenzoic acid (nOBA) compounds. The induced smectic B phase with different texture (spine texture, needle texture, mosaic texture, natural mosaic texture and marble texture) were identified by polarizing optical microscope. Due to breaking of in-plane rotational symmetry within molecular layers, smectic B phase is tempted by suppressing other usual mesophases. The mesomorphic transition temperature, enthalpy and entropy values were calculated by differential scanning calorimeter which strongly proves the existence of mesomorphism. H-bond interaction and functional groups were confirmed by the observed peak between 2910 and 2954 cm^-1 in the FTIR spectra. Thermal stability and extended mesophase width (for MGA + 12OBA = 31.1) of Sm B mesophase were reported and it clearly reveals the existence of mono-phase variance in the MGA + nOBA HBLC complex. Due to the steric effect, and the increased molecular core polarity, the highly stabilized Sm B phase with different textures were observed while varying alkyloxy carbon number n = 7 to 12. Further, the origination of Sm B phase and its detailed characteristics were reported.

Size- and surface functionalization-driven molecular interaction of CdSe quantum dots with jack bean urease: multispectroscopic, thermodynamic, and AFM approach

Quantum dots (QDs) with distinctive optical properties have been extensively researched and developed for usage in solar cells, imaging, drug delivery, cellular targeting, etc. But the inevitable production of QDs can lead to their unavoidable release and increased environmental concentration. Depending on morphological and surface properties, QDs at the nano-bio interface considerably impact the activity and structure of bio-molecules. The present study investigates the interaction of metalloenzyme jack bean urease (JBU) and bi-sized CdSe QDs (2.43 nm and 3.63 nm), surface-functionalized to mercaptopropionic acid (MPA) (-COOH), L-cysteine (CYS), L-glutathione (GSH), N-acetyl L-cysteine (NAC) (-COOH, -NH₂), and cysteamine hydrochloride (CYST) (-NH₂) to assess any alterations in JBU's binding, microenvironment, structure, exciton lifetime, and activity. JBU catalyzes the hydrolysis of urea to produce ammonia and carbon dioxide; any changes in its properties could threaten the survival of several microbes and plants. Spectroscopy techniques such as UV-Vis, fluorescence, circular dichroism, synchronous, time-resolved fluorescence, atomic force microscopy, and JBU activity assay were studied. Results suggested highly spontaneous and energy-favored interactions, which involved static quenching and hydrophobic forces of varied magnitude, dependent on QDs properties. The size, surface modifications, and dosage of QDs significantly impacted the secondary structure and activity of JBUs. Even though the larger sizes of the relevant modifications demonstrated stronger binding, the smaller sizes had the greatest impact on α-helicity and activity. CYST-capped QDs with an average number of the binding site (n) = 1, reduced α-helicity by 16% and activity by 22-30% at 7 nM concentration. In contrast, MPA-capped QDs with n < 1 had the least effect on α-helical structure and activity. The smaller GSH-capped QDs increased the activity by 9%, via partially restoring JBU's α-helical content. The study thus thoroughly analyzed the impact of varied-size and surface-functionalized QDs on the structure and function of JBU, which can be exploited further for several biomedical applications.

Graphene-assembly liquid crystalline and nanopolymer hybridization: A review on switchable device implementations

Two-dimensional graphene and its hybrid derivatives combined with liquid crystals, polymers, and nanomaterials enable the formation of hybrid nanocomposites possessing extraordinary and unique properties. Among others, these assemblies could exhibit stimulus-induced optical and electrical changes, which are essential for many new switchable device technologies. The current review deals straight forward and versatile techniques of the fabrication of exclusive graphene self-assembly of liquid crystalline polymer nanocomposite which exhibiting novel emerging equities as well as unique functionalities. Unique design makes hybrid composite matrix multidomain structures serve as both alignment and conductive layers, thus sustaining novel switchable device fabrication mechanism. Exhibited ultra thin-film nanocomposite based smart switchable devices are promising candidates for diverse applications in the field of stretchable electronics, energy storage, photodetectors, high contrast displays, and optoelectronics. Furthermore, the brand new device implementation through novel materials have the potentials of cost-effective production, large-area compatibility and scalability, and seamless heterogeneous integration.

Phytosynthesized nanoparticles as a potential cancer therapeutic agent

Plants are the well-known sources for the hyper-accumulation and reduction of metallic ions. Analysis of various plant extracts has justified the presence of different types of phytochemicals that possess the stabilization and reduction functionalities of precursors to form nanoparticles. Such characteristics make plants as an attractive source for synthesizing eco-friendly nanoparticles (NPs) with potentially less toxicity to the body. Recently, phytosynthesized nanoparticles have been explored for targeted inhibition and diagnosis of cancer cells without affecting non-cancerous healthy cells. The aim of this review is to discuss the characteristic performance of NPs synthesized from various plant sources for the diagnosis and inhibition of cancer. The mode of action of phytosynthesized nanoparticles for anti-cancer applications are also discussed.

Poly (butylene succinate) and derivative copolymer filled with Dendranthema grandiflora biolarvicide extract

Dengue is the most important infectious disease in the world and is a severe public health problem. The chikungunya is an arbovirus, in many cases, increased, which is transmitted by the same transmitter dengue vector, Aedes aegypti. The symptoms of both diseases are similar, and infections can be lethal. Although there is no preventive vaccine against any of the two diseases, therefore, it is extremely important to control the mosquito. The eggs of A. aegypti are very resistant and hatch into larvae, which later give rise to mosquitoes in any container with water. Natural plant extracts have come from active substances with larvicidal activity against A. aegypti. However, they tend to be highly hydrophobic and need some strategy to improve its affinity for water. Because of these factors, this research aims to synthesize and characterize polymeric materials with properties suitable for the release of hydrophobic principles with larvicidal action. The synthesized polymers are poly (butylene succinate) (PBS) and PBS block copolymer with polyethylene glycol (PEG). The synthesized polymers were characterized by nuclear magnetic resonance, thermal analysis simultaneous, differential scanning calorimetry, Fourier transform infrared spectroscopy, and diffraction of X-rays analysis. The analysis results showed that the synthesized materials have chemical composition and properties suitable for use in the controlled release of actives substances. Systems were prepared using the Dendranthema grandiflora extract, which has larvicidal activity was incorporated via fusion to polymers, to evaluate its release in aqueous media. The results proved that higher amounts of PEG in the copolymer chain speed up the delivery of the larvicidal extract. Besides that, the larvicidal extract concentration required to cause death larvae of A. aegypti was achieved from the first minutes of dissolution tests, indicating that the materials developed are promising tool to fight dengue and chikungunya. This new system is a vital tool for eliminating vectors, potentially contributing to saving millions of lives worldwide.

Microbial acetylcholinesterase inhibitors for Alzheimer's therapy: recent trends on extraction, detection, irradiation-assisted production improvement and nano-structured drug delivery

Abstract

Neurodegenerative disorders especially Alzheimer’s disease (AD) are significantly threatening the public health. Acetylcholinesterase (AChE) inhibitors are compounds of great interest which can be used as effective agents for the symptomatic treatment of AD. Although plants are considered the largest source for these types of inhibitors, the microbial production of AChE inhibitors represents an efficient, easily manipulated, eco-friendly, cost-effective, and alternative approach. This review highlights the recent advances on the microbial production of AChE inhibitors and summarizes all the previously reported successful studies on isolation, screening, extraction, and detecting methodologies of AChE inhibitors from the microbial fermentation, from the earliest trials to the most promising anti-AD drug, huperzine A (HupA). In addition, improvement strategies for maximizing the industrial production of AChE inhibitors by microbes will be discussed. Finally, the promising applications of nano-material-based drug delivery systems for natural AChE inhibitor (HupA) will also be summarized.

Key Points

• AChE inhibitors are potential therapies for Alzheimer’s disease.

• Microorganisms as alternate sources for prospective production of such inhibitors.

• Research advances on extraction, detection, and strategies for production improvement.

• Nanotechnology-based approaches for an effective drug delivery for Alzheimer’s disease.