Using Ultraviolet-visible Research Articles

Microwave Green Synthesis of Alumina Nanoparticles and Evaluation of Their Characterization and Microbial Effect

This research set out to provide a faster, easier, and more efficient process for nanoparticle (NP) synthesis of aluminum oxide NPs preparation by microwave irradiation, using plant extracts separately and in the same way (tea, coffee, rosemary), which is an easy-to-use and inexpensive method. The structural properties were investigated by X-ray diffractometer analysis technique (XRD). The X-ray analysis shows the structure has a polycrystalline nature with a hexagonal phase. The optical properties were studied using ultraviolet visible (UV-Vis) spectrometer, where the energy gap was determined. The surface morphology properties of the prepared aluminum NPs were examined by atomic force microscope (AFM). The Fourier transform infrared (FTIR) spectroscopy verified the presence of Al-O, C–O, and C–H bonds, this study confirms the high reducing and capping capacity of aluminum NPs via biomolecules found in the plant extract. The inhibitory activity of these Al2O3-NPs was observed, along with their potential to enter the bacterial cell wall and hinder its activity.

Calotropis procera Mediated Synthesis of Silver Nanoparticles and its Antibacterial Effect on Selected Pathogens

This study investigates the green synthesis and antibacterial potential of silver nanoparticles (AgNPs) derived from Calotropis procera leaf extract. The AgNPs was characterized using Ultraviolet-Visible (UV-VIS) Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Scanning and Transmission Electron Microscopy (SEM and TEM), Energy Dispersive X-ray (EDX) and X-ray Diffraction (XRD). The spectrum from UV-VIS had a peak centered at 445 nm confirming the formation of AgNPs, SEM-TEM micrographs showed them as aggregated, spherical in shape and about 15.30 – 17.66 nm in size, while EDX revealed Ag with highest proportion (75.56 %). The FTIR analysis revealed the presence of functional groups such as alcohols, ethers, esters, alkenes, carboxylic acid and amines. The XRD confirmed the crystalline nature of the synthesized CP-AgNPs. The synthesized AgNPs showed strong antibacterial activity against Escherichia coli (18.1±0.2 mm), Enterobacter sichuanensis (16.8±0.5 mm), Pseudomonas aeroginosa (14.4±0.3 mm), Staphylococcus aureus (22.2±0.5 mm) and Streptococcus agalactiae (21.5±0.1 mm). This study demonstrates an efficient, eco-friendly method for synthesizing AgNPs with strong antibacterial potential, which could be valuable for developing alternative antimicrobial agents.

Stacking-order independent inter-layer charge transfer in MBE-grown MoSe2 and WSe2 heterostructures

MoSe2/WSe2 heterostructure is gaining significant research interest due to its unique electrical and optical properties, making them suitable for various advanced applications. This work focuses on inter-layer charge transfer effects on MBE-grown MoSe2 and WSe2 heterostructures. Bilayer (BL)-MoSe2/BL-WSe2 and BL-WSe2/BL-MoSe2 have been grown over a c-plane sapphire substrate using molecular beam epitaxy (MBE). Different characterization techniques including Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and reflection high-energy electron diffraction (RHEED) confirm the phase, composition, surface morphology, and crystalline quality of the films, respectively. The band diagram using Ultraviolet-visible (UV-Vis) spectroscopy, XPS core level spectra, XPS valence band spectra and surface work function shows that individual MoSe2 and WSe2 BLs grown over c-plane sapphire are n-type and p-type semiconductors, respectively. This study shows that when the individual BLs form MoSe2/WSe2 and WSe2/MoSe2 heterostructures, a unidirectional electron transfer occurs from the WSe2 to MoSe2, which is independent of WSe2 and MoSe2 stacking order. As a result, the Fermi level position changes for both the materials in their heterostructures, which makes MoSe2 more n-type semiconductor and WSe2 more p-type semiconductor. MoSe2/WSe2 and WSe2/MoSe2 heterostructures show a type II band alignment with a conduction band offset of 0.57 eV and a valance band offset of 0.51 eV These findings contribute to a deeper understanding of the interfacial charge transfer effects and design of MoSe2 and WSe2 heterostructures for potential device applications.

Early plant disease diagnosis through handheld UV-Vis transmittance spectrometer with DD-SIMCA one-class classification and MCR-ALS bilinear decomposition

A novel non-destructive analytical method for early diagnosis of two bacterial diseases, Pseudomonas syringae and Xanthomonas euvesicatoria, in tomato plants, using ultraviolet-visible (UV-Vis) transmittance spectroscopy and chemometric tools, is developed. Plant-pathogen interactions caused tissue damage that generated non-linear data patterns compared to the control set (healthy samples), which complicates traditional discrimination models, even when employing non-linear discriminant approaches. Alternatively, an authentication task to conduct one-class classification relying on a data-driven version of soft independent modeling of class analogy (DD-SIMCA) is a wise choice due to its quadratic approach, proper to deal with non-linear data. DD-SIMCA detached the target class (control healthy plant leaflet tissues) from all other samples (target class and non-target class of plant leaflet tissues inoculated with two bacteria, even before the manifestation of macroscopic lesions associated with the diseases) by capturing the main similarities within the samples of the target class through the full distance that acts as a classification analytical signal, reaching 100% sensitivity in the training and validation sets. Multivariate curve resolution constrained analysis allowed the description of the bacterial inoculation process on diseased tissues through pure spectral signatures. DD-SIMCA results indicate that non-target class of samples with higher proximity to the acceptance boundary suggested that they were at earlier stages of infection compared to more distant ones, presenting lower full distance values. These findings reveal that a handheld UV-Vis transmittance spectrometer is sufficiently sensitive to be used in acquiring biological data with suitable chemometric modeling for early disease diagnosis and prompt intervention.

Octylamine-oxalic acid (Oct-Oxa) deep eutectic solvent for the separation of Sudan II from food samples

This work presents a novel deep eutectic solvent (DES) formed of octylamine and oxalic acid (Oct-Oxa) that was effectively used to separate Sudan II dye from food and water samples. The prepared DES was characterized using Fourier transform infrared spectroscopy (FT-IR) and carbon-13 nuclear magnetic resonance (13C NMR). Key parameters were optimized, including a short ultrasonication time of 30 s and a very low DES volume of only 500 μL that could be separated within one minute of centrifugation. The remaining parameters were also tested: pH (7), DES molar ratio (1:1), and sample volume (40 mL). The method demonstrates excellent recovery and accuracy, with limits of detection (LOD) of 1.2 μg kg−1 and quantification (LOQ) of 4.1 μg kg−1. It facilitates rapid separation and sensitive detection of Sudan II dye using ultraviolet-visible (UV-VIS) spectrophotometry. The novelty of this approach lies in the use of a novel DES, the minimal volume of DES required, and the efficiency of the short ultrasonication time, highlighting the method's potential for sustainable, cost-effective extraction in environmental and food safety applications.

The biosynthesis of ZnO nanoparticles using Synadenium grantii latex: characterization and evaluation of their antimicrobial activities

The steadily rising incidences of microbial and infectious diseases pose a direct threat to both human and animal sustainability. Over the previous 20 years, the expectations for eco-friendly nanoparticles application as contemporary medicinal agents have grown. This is why, as opposed to using hazardous chemicals, researchers have recently concentrated on simple, green, sustainable, and affordable ways to create nanoparticles. This research aimed to use the latex of Synadenium grantii to synthesize ZnO NPs (zinc oxide nanoparticles) using a simple and environmentally friendly technique. The observation of the maximum wavelength at 365 nm using Ultraviolet-visible (UV-Vis) spectrometry signified the formation of zinc oxide nanoparticles. The FT-IR (Fourier transform-infrared) spectrometry indicated the bands of various biomolecules (mainly polyphenols at 1541 cm-1 wavenumber) involved in reducing and capping zinc oxide nanoparticles. The XRD spectrum demonstrated the wurtzite phases of ZnO nanoparticles of 24 nm in size. The synthesized ZnO NPs demonstrated great anti-microbial potency compared to the positive control (ampicillin) as tested on Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The study confirmed the presence of various chemical compounds in latex of Synadenium grantii responsible for the synthesis of ZnO NPs with enhanced anti-bacterial effects in comparison to the latex extract.

Antibacterial Activity of Phyto-Synthesized Silver Nanoparticles From Dryopteris cristata Against Staphylococcus aureus ATCC 28923 and Escherichia coli ATCC 28922.

Introduction Nanotechnology has emerged as a vital field, particularly in synthesizing nanoparticles. Silver nanoparticles (AgNPs) are recognized for their strong antimicrobial properties against various pathogens, including Staphylococcus aureusand Escherichia coli, due to their small size and high surface area. Green synthesis using plant extracts offers an eco-friendly alternative. The rise of multidrug-resistant bacteria underscores the urgent need for new antimicrobial agents. This study investigates the antibacterial activities of Dryopteris cristata AgNPs (DC-AgNPs) against S. aureusand E. coli, employing antimicrobial susceptibility testing (AST), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assessments, along with nanoparticle characterization. Materials and method The antimicrobial activity ofDC-AgNPs was evaluated using clinical isolates of E. coliand S. aureus. Bacterial inoculums were standardized to 0.5 MacFarlard (1.5 × 108 CFU/mL) and tested via a modified agar-well diffusion method. The MIC and MBC were determined using broth microdilution and sub-culturing methods, respectively. Characterization of the nanoparticles was conducted using Ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Results and conclusion D. cristatawas identified as the plant used to synthesize AgNPs, confirmed by the University of Ilorin, Nigeria. Phytochemical screening revealed the presence of tannins, flavonoids, glycosides, and phenolics. The AgNPs were synthesized by adding the aqueous extract to silver nitrate, resulting in a color change. Characterization via UV-Vis spectrophotometry confirmed nanoparticle formation. Antimicrobial testing showed that DC-AgNPs effectively inhibited S. aureusand E. coli, with minimum inhibitory concentrations of 125 μg and 250 μg, respectively, indicating their potential as antimicrobial agents.

A Dy(III) Coordination Polymer Material as a Dual-Functional Fluorescent Sensor for the Selective Detection of Inorganic Pollutants.

A Dy(III) coordination polymer (CP), [Dy(spasds)(H2O)2]n (1) (Na2Hspasds = 5-(4-sulfophenylazo)salicylic disodium salt), has been synthesized using a hydrothermal method and characterized. 1 features a 2D layered structure, where the spasda3- anions act as pentadentate ligands, adopting carboxylate, sulfonate and phenolate groups to bridge with four Dy centers in η3-μ1: μ2, η2-μ1: μ1, and monodentate coordination modes, respectively. It possesses a unique (4,4)-connected net with a Schläfli symbol of {44·62}{4}2. The luminescence study revealed that 1 exhibited a broad fluorescent emission band at 392 nm. Moreover, the visual blue color has been confirmed by the CIE plot. 1 can serve as a dual-functional luminescent sensor toward Fe3+ and MnO4- through the luminescence quenching effect, with limits of detection (LODs) of 9.30 × 10-7 and 1.19 × 10-6 M, respectively. The LODs are relatively low in comparison with those of the reported CP-based sensors for Fe3+ and MnO4-. In addition, 1 also has high selectivity and remarkable anti-interference ability, as well as good recyclability for at least five cycles. Furthermore, the potential application of the sensor for the detection of Fe3+ and MnO4- was studied through simulated wastewater samples with different concentrations. The possible sensing mechanisms were investigated using Ultraviolet-Visible (UV-Vis) absorption spectroscopy and density functional theory (DFT) calculations. The results revealed that the luminescence turn-off effects toward Fe3+ and MnO4- were caused by competitive absorption and photoinduced electron transfer (PET), and competitive absorption and inner filter effect (IFE), respectively.

The Study of Calcium Chloride Effect on Silver Nanoparticles Capping with Roselle Extract Granule against Aggregatibacter actinomycetemcomitans

Abstract Objectives The primary aim of this research is to investigate the influence of calcium chloride on the synthesis of silver nanoparticles coated with roselle extract and enclosed within alginate and calcium chloride (SNP-Ro-CaCl2) beads, designated as SNP-Ro-CaCl2 beads. Additionally, the study aims to assess their antimicrobial activity. Materials and Methods For the preparation of SNP-Ro-CaCl2 beads, SNPs and alginate gel were mixed, followed by dropping in three different concentrations of CaCl2 solution (1%, 3%, and 5% w/v). The morphological structure of the SNP-Ro-CaCl2 beads was analyzed using a stereoscope and scanning electron microscope (SEM). Over a period of 14 days, the release of SNPs was monitored using ultraviolet-visible (UV-Vis) spectroscopy. Additionally, the activity against Aggregatibacter actinomycetemcomitans was evaluated using the disk diffusion technique. Statistical Analysis The data for this experiment were analyzed using one-way analysis of variance (ANOVA) and Scheffe's method. Results The results revealed that varying concentrations of calcium chloride had distinct crosslinking effects on alginate, resulting in different voids and porosity within the SNP-Ro-CaCl2 beads. In the SNP-Ro-1% CaCl2 beads, the inner element exhibited higher porosity, facilitating faster activation and greater efficiency in releasing SNPs. Regarding activity against A. actinomycetemcomitans after 14 days, SNP-Ro-1% CaCl2 beads showed a larger inhibition zone diameter compared to other concentrations, while no statistically significant difference in the inhibition zone diameter was observed between SNP-Ro-3% CaCl2 and SNP-Ro-5% CaCl2 beads. Additionally, it was observed that the antimicrobial effectiveness diminished after 17 days through testing of the lifetimes of the three concentrations. Conclusions This study developed a method for depositing SNP-Ro into alginate gel and crosslinking it with CaCl2 to produce small beads for the sustained release of SNP-Ro in periodontal lesions. Consequently, the SNP-Ro-CaCl2 beads have the potential to be developed as adjunctive locally delivered antimicrobial agents in periodontal therapy.

Characterization of Silver Nanoparticles Synthesized With Fungi Isolated From Cocoa and Orange Plantation Soils

Green synthesis of nanoparticles with various metals is being interested among researchers globally attention for due to their safety, environmental friendliness and non-toxicity in contrast to chemical synthesis. Here, fungi were isolated from rhizosphere of cocoa and orange obtained from Federal University of Technology, Akure using standard mycological techniques with the aim of synthesizing silver nanoparticles. The silver nanoparticles synthesized by these fungal isolates were characterized using Ultraviolet-Visible (UV-Vis) and Fourier Transmission Infra- Red (FTIR) spectroscopy. Seven fungi isolated from the soil samples viz. Nigrospora sphaerica, Penicillium discolor, P. digitatum, Neurospora crassa, Alternarium infectoria, Trichophyton verrucosum and Mucor mucedo. The colour transformation from yellow to brown indicated the formation of silver nanoparticles. All the isolates showed an intense peak in the wavelength range of 410-440 nm. The FTIR analysis of silver nanoparticles synthesized by N. sphaerica, P. discolor, P. digitatum, N. crassa, A. infectoria, T. verrucosum and M. mucedo revealed the existence of a band at different stretches of bonds at different peaks of 3314.36 cm-1, 3310.47 cm-1, 2412.22 cm-1, 3912.33 cm-1 3614.52 cm-1, 3852.11 cm-1 and 2112.11 cm-1, respectively. The silver nanoparticles synthesized could have the potential application in agricultural, pharmaceutical and food industries as well as petrochemical industries for the clean - up of crude oil contaminated soils. J. Bio-Sci. 32(2): 31-44, 2024

Eco-benevolent synthesis of ZnO-NPs and ZnO-MFs from Inula oculus-christi L. (Asteraceae) with effective antioxidant, antimicrobial, DNA cleavage, and decolorization efficiencies.

As a result of the changes occurring globally in recent years, millions of people are facing challenging and even life-threatening diseases such as cancer and the COVID-19 pandemic, among others. This phenomenon has spurred researchers towards developing and implementing innovative and environmentally friendly scientific methods, merging disciplines with significant technological potential, such as nanotechnology with medicinal plants. Therefore, the focus of this research is to synthesize zinc nanoparticles (ZnO-NPs) and microflowers (ZnO-MFs) using extracts of the medicinal plant I. oculus christi prepared in n-hexane and methanol as new bioreduction and capping agents through a simple and environmentally friendly chemical approach. Optical, thermal, and morphological structural analyses of ZnO-NPs and ZnO-MFs were conducted using Ultraviolet-Visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FT-IR) spectroscopy, Thermogravimetric Analysis (TGA), and Field Emission Scanning Electron Microscopy (FE-SEM). Metabolic profiles of extracts from different plant parts were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS) and supported by visualization of contents through Principal Component Analysis (PCA), hierarchical cluster analysis heatmaps, and Pearson correlation graphs. Interestingly, ZnO-NPs and ZnO-MFs exhibited strong antioxidant properties and demonstrated particularly potent antimicrobial activity against Micrococcus luteus NRRL B-4375, Escherichia coli ATCC 25922, and Candida albicans ATCC 10231 strains compared to standard antibiotics. Furthermore, ZnO-NPs and ZnO-MFs showed excellent plasmid DNA-cleavage activity of pBR322 with increasing doses. The photocatalytic performance of the synthesized ZnO-NPs and ZnO-MFs was evaluated for methylene blue (MB), congo red (CR), and safranin-O(SO) dyes, demonstrating remarkable color removal efficiency. Overall, the results provide a promising avenue for the green synthesis of ZnO-NPs and ZnO-MFs using I. oculus-christi L. inflorescence and pappus extracts, potentially revolutionizing biopharmaceutical and catalytic applications in these fields.

Structural and Optical Properties of Graphene Oxide:Zinc Oxide on Different Types of Substrates

The structural and optical properties of ZnO-based nanostructure exhibit substrate-dependent variations. A comprehensive understanding of how different substrates influence the crystalline structure, absorbance and surface morphology of the deposited films remains a great challenge. This study was done to investigate the structural and optical properties of zinc oxide (ZnO) that alter with graphene oxide (GO) deposited on various substrates; glass, silicon, indium tin oxide (ITO) and polyethylene terephthalate (PET) by solution immersion method. The structural properties were studied using X-ray diffraction (XRD) and Fourier-transform infrared (FTIR). The optical properties of samples were determined using ultraviolet-visible (UV-VIS) spectroscopy and Raman spectroscopy. The XRD result revealed that all GO/ZnO samples have polycrystalline structures while FTIR showed the presence of C-O, C=O and C-H compounds on all substrates. The highest absorbance of 3.40 was shown by the GO/ZnO sample which was grown on a glass substrate while the lowest absorbance of 1.50 was exhibited by the sample that was grown on PET substrate. Based on the Raman spectrum all samples showed variety in phonon energy when ZnO was grown on different substrates.

Macroalgal (Ulva compressa) Silver Nanoparticles: Their Characterization, Cytotoxicity, and Antibacterial Applications

In this study, an extract of Ulva compressa (UC), a green macroalgae, was used to synthesize biogenic silver nanoparticles (AgNPs). The formation of nanoparticles (NPs) was evaluated and confirmed by using ultraviolet-visible (UV-VIS) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) analyses. UV-VIS spectra showing absorption peaks at 450 nm confirmed the formation of AgNPs. The particles were crystalline in nature according to the XRD pattern. AgNPs formation was proved by the FT-IR spectrum of UC. TEM image showed that the average particle size was 4.55 nm. The antimicrobial and anticarcinogenic activity was evaluated for the synthesized AgNPs. AgNPs obtained from algae demonstrated antimicrobial activity against all bacteria including B. subtilis, E. faecalis, S. mutans, E. coli, S. aureus, and S. pyogenes. The NPs were shown to have anticarcinogenic activity on HEK 293, MCF-7, and HeLa (reducing viability by 25.42%, 46.42%, and 62.42%, respectively) cell cultures. These findings indicate that AgNPs can be useful medicinal compounds. Green synthesized NPs can be developed and utilized as anticancer agents in the treatment of various types of cancer, as well as their antimicrobial effects can be utilized to ensure the long-term sustainability of food in this study.

A review of the antimicrobial benefits of naturally extracted nanomaterials

Nanotechnology finds immense potential due to the unique characteristics of nanomaterials. Though noble metal nanoparticles, particularly gold and silver nanoparticles possess advanced properties their conventional production methods pose environmental hazards. This paper explores the eco-friendly approaches using natural sources for synthesizing gold and silver nanoparticles. Rose and pomegranate extracts were used to synthesize gold nanoparticles. Evaluation using ultraviolet-visible (UV-Vis) spectroscopy confirmed the nanoparticle formation, and Fourier transform infrared spectroscopy (FT-IR) analysis recognized the presence of plant-derived compounds for stabilizing these particles. In-depth observations of their size and form were provided using electron microscopy, and these findings were aligned with the inferences made from the UV-Vis data. Silver nanoparticles were produced using Ocimum gratissimum leaf extract (OGE), exhibiting dose-dependent antimicrobial effects against bacterial strains. A comparative analysis demonstrated the distinct antibacterial characteristics of silver and gold nanoparticles against several bacterial strains. These nanoparticles demonstrated enhanced inhibitory effects when employed in combination with antibiotics, suggesting the possibility of dealing with antibiotic resistance. The study presents opportunities for producing nanomaterials with minimal impact on the environment and for addressing antibiotic resistance. Further research can enhance the process and find more useful applications as this green synthesis approach can bring about significant improvements in many areas.

Colloidal synthesis of ZnTe nanocrystals by laser ablation and fabrication of hybrid light emitting device

Zinc telluride (ZnTe) nanocrystals (NCs) have generated the interest of researchers as an electrode material in hybrid light emitting devices (HLEDs) due to its potentially high capacity. However, due to the restricted fundamental charging capacity of the electrode materials, the available energy of existing nanomaterial light emitting devices remains enough for a wide range of applications. In this research, ZnTe nanocrystals were synthesized using Nd: YAG laser at energy 600 mJ by 150 pulse number to form a battery device out of ITO/ZnTe/TPD/Ni. The spectra of the ZnTe NCs were assessed using ultraviolet-visible (UV-VIS) and photoluminescence (PL). The results proved that the synthesized NCs were nanocrystalline structures. The energy gap (Eg) within ZnTe NCs regarded as (PL) spectrum has been identified to be about 3.6 eV. ZnTe NCs produced via laser ablation enhance the functionality of the HLEDs by increasing the carrier's charge mobility and, as a further benefit, by facilitating recombination processes inside ZnTe NCs with TPD organic polymer. In addition to lighting at 3V, current-voltage (I-V) specifications establish suitable environment as well as formation.

Photophysical Properties of Sinapic Acid and Ferulic Acid and Their Binding Mechanism with Caffeine.

Sinapic acid (SA) and ferulic acid (FA) are bioactive compounds used in the food, pharmaceutical, and cosmetic industries due to their antioxidant properties. In this work, we studied the photophysical properties of SA and FA in different solvents and concentrations and their interactions with caffeine (CF), using ultraviolet-visible (UV-Vis), fluorescence spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The findings show that the quantum yield, fluorescence lifetime, radiative decay rates, and non-radiative decay rates of SA and FA are influenced by the concentrations and solvent polarity. The interaction between SA and FA with CF was also studied using UV-Vis and fluorescence spectroscopy. The results indicate that the CF quenched the fluorescence intensity of SA and FA by static quenching due to the formation of a non-fluorescent complex. The van't Hoff equation suggests that the van der Waals forces and hydrogen bonds force were responsible for the interaction between SA and CF, as indicated by a negative change in enthalpy ( < 0) and a negative change in entropy ( < 0). On the other hand, the interaction between FA and CF was primarily controlled by electrostatic force, as indicated by a negative change in enthalpy ( < 0) and a positive change in entropy ( > 0). The negative change in Gibbs free energy ( ) indicates that both compounds underwent a spontaneous binding process.

Characterization of Titanium Dioxide Thin Films Grown on Glass Substrate by Gasified-Thermal-Carrier-Assisted Evaporation Technique: Impact of Deposition Time

In this study, a gasified thermal carrier assisted vapor deposition technique has been used to deposit titanium dioxides thin films of 90, 270, and 480 nm, thicknesses on glass substrates at growth times of 1, 2, and, 3 hours respectively. Varied nondestructive techniques were employed to investigate the impacts of deposition time on the structural, optical, and electrical properties of the TiO2 thin films. X-ray diffraction (XRD) showed that crystals of a polycrystalline nature were preferentially oriented along the (101) direction. The analysis of the chemical composition of the films by energy-dispersive X-ray (EDX) spectroscopy demonstrated very pure TiO2 thin films that were free of contamination and impurities. The SEM images indicated that the TiO2 thin films were cluster forms, with increasing sizes of with the growth times of 1, 2, and, 3 hours, and these times produced thicknesses of 90, 270, and 480 nm, respectively. The study of the optical properties using ultraviolet-visible (UV-Vis) spectroscopy revealed a thickness-inverse relationship between the films’ optical transmittance levels (from 92% to 78%) and their corresponding energy bandgaps. The electrical properties of the TiO2 films were analyzed via a Hall effect measurement system. The electrical resistivity levels of the films were highly correlated with the thicknesses of the films. The lowest value of electrical resistivity for the highest thinness was 55×103Ω· cm. The films showed high densities of carriers, with concentrations of 85×1012 to 35×1013 N (cm−3), and sufficiently low shift resistance levels. According to the obtained results, three hours, which led to the growth of a 270 nm thickness, could be considered as the ideal deposition time for TiO2 thin films for solar cell applications.

Mikania micrantha silver nanoparticles exhibit anticancer activities against human lung adenocarcinoma via caspase-mediated apoptotic cell death

Green-mediated synthesis of nanoparticles has earned a promising role in the area of nanotechnology due to their biomedical applications. This study describes the synthesis of silver nanoparticles (AgNPs) using Mikania micrantha leaf extract and its functional activities against cancer. The synthesis of AgNPs was confirmed using Ultraviolet-Visible (UV-Vis) spectrum that exhibited an absorption band at 459 nm. The bioactive compounds of M. micrantha leaf extract that functioned as reducing and capping agents were confirmed by a shift in the absorption bands in Fourier Transform Infra-red Spectroscopy (FT-IR). Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) studies validated the spherical shape and size of AgNPs, respectively. Energy Dispersive Spectroscopy (EDS) analysis revealed the presence of elemental silver. The crystalline nature of AgNPs was confirmed by the X-ray Diffraction Analysis (XRD). AgNPs effectively induced cytotoxicity and prevented A549 cell colony formation in a dose-dependent manner. Treatment of A549 cells with AgNPs also increased DNA damage, which was coupled with elevated lipid peroxidation and decreased antioxidant enzymes such as glutathione (GSH), glutathione-s-transferase (GST), and superoxide dismutase (SOD). Following AgNPs treatment, the mRNA expression levels of the pro-apoptotic genes as well as the activities of caspases were significantly elevated in A549 cells while the expression levels of anti-apoptotic genes were downregulated. Our study demonstrates the potential of the synthesised AgNPs for cancer therapy possibly targeting the apoptotic pathway.

Effectiveness of white tea-mediated silver nanoparticles as an intracanal irrigant against Enterococcus faecalis: An in vitro study.

The probability of a positive outcome of root canal therapy is substantially higher if the infection is eradicated successfully before the obturation of the root canal system. Irrigation is an essential aspect of root canal debridement, as it enables more thorough cleaning than is possible with root canal instrumentation alone. To overcome the side effects of chemical irrigants, there has been a search for herbal medicines as substitutes. The aim of the present study was to explore the antimicrobial efficacy of white tea-mediated silver nanoparticles (AgNPs) formulated as an intracanal irrigant against Enterococcus faecalis, and to compare it with the efficacy of chlorhexidine and sodium hypochlorite irrigants. The experimental groups were as follows: group I - white tea-mediated AgNPs; group II - 2% chlorhexidine; and group III - 2.5% sodium hypochlorite. The characterization of AgNPs was performed using ultraviolet-visible (UV-Vis) spectroscopy and transmission electron microscopy (TEM) analysis. Enterococcus faecalis was inoculated onto Mueller-Hinton agar plates. The disks impregnated with irrigants were placed on the inoculated plates and incubated aerobically at 37°C for 24 h. Then, the growth inhibition zones were measured. Statistical analysis was performed using the one-way analysis of variance (ANOVA) and the post hoc tests. A concentration of 50 μL of white tea-mediated AgNPs exhibited the greatest zone of inhibition (32 ±2 mm), followed by 2% chlorhexidine (25 ±1 mm) and 2.5% sodium hypochlorite (23 ±3 mm). White tea-mediated AgNPs showed promising results in the elimination of E. faecalis, being superior to chlorhexidine and sodium hypochlorite irrigants.

Effect of sulphidation process on the structure, morphology and optical properties of GO/AgNWs composites.

In this study, composite materials composed of graphene oxide (GO) synthesized by a modified Hummers' method and silver nanowires (AgNWs) synthesized by a modified polyol method were prepared. The prepared composites were subjected to sulfidation under the influence of H2S gas. Structural changes in the samples were evaluated using X-ray diffraction (XRD). The binding nature of the composite was characterized using FT-IR spectroscopy. Optical properties and band gap values were investigated using ultraviolet-visible (UV-Vis) spectroscopy. The morphology of the composites was analyzed by transmission electron microscopy (TEM). A simple method using H2S gas was applied for the sulphidation process of the samples. The sulfidation process was successful under the influence of H2S gas, resulting in an increased distance between the GO layers and a decrease in the band gap value for the composite post-sulfidation. In addition, AgNWs were observed to decompose into Ag2S nanoparticles under the influence of H2S gas. It was determined that the value of the band gap of the sample changes because of sulphidation.