UV-Vis Spectrophotometry Research Articles

Enhancing the stability and bio-accessibility of carotenoids extracted from canistel (Lucuma nervosa) via liposomes encapsulation

Canistel (Lucuma nervosa) is a valuable natural source of carotenoids, but their use in the food industry is hampered by low extraction efficiency, poor stability, and limited bio-accessibility. HPLC results showed that a deep eutectic solvent (DES) composed of D-menthol and canoic acid (Men-CaA) has significantly higher extraction yields for lycopene (498.66 ± 3.20 μg/mL DW) and β-carotene (6.43 ± 0.23 μg/mL DW) than corn oil. UV-VIS spectrophotometry combined with response surface methodology results confirmed that the best encapsulation efficiency of liposome for lycopene and β-carotene was attained in the temperature range of 30–70 °C, with the ratio of carotenoid extract to liposome of 1:25 (w/w), the ratio of phospholipids to cholesterol, and the ratio of aqueous phase to lipid phase of 2:1 (v/v). SEM analysis revealed that liposome-encapsulated carotenoid extract formed spherical structures with a uniform texture and rough surface. The ζ-potential assay confirmed the highest stability of liposomes at pH 7. FTIR spectroscopy indicated effective encapsulation of canistel-derived carotenoids by liposomes. Furthermore, liposomes encapsulation improved the thermal and storage stability and bio-accessibility of lycopene and β-carotene. Encapsulating canistel carotenoids in liposomes significantly enhances their stability and bio-accessibility, presenting a viable strategy for preserving the efficacy of food-based active ingredients.

الاستخلاص الانتقائي للكليميبيرايد في المستحضرات الصيدلانية وفي مصل الانسان عن طريق تقنية MIP-SPE المركبة

This paper demonstrates that the synthesizing and storage of molecular-imprinted polymers (MIP) at room temperature using bulk polymerisation of Glimepiride (Glim.) is characterized by high sensitivity, reduced costs, increased stability, and extended life. The research used 1:15:20 mmol ratios of template, monomer and cross-linking agents for the polymerisation in order to ensure an appropriate adsorption capacity. Benzoyl peroxide BPO was employed as the initiator for the functional monomer Allyl chloride C3H5Cl , cross-linked with Ethylene glycol dimethacrylate EGDMA C10H14O4, thereby creating MIP for Glimepiride (Glim-MIP) that could be characterised with UV-Visible Spectrophotometry at 274.5nm, for pharmaceutical drugs. Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) was used for the human serum. The elution process that was applied to the template (Glim.) from the Glim-MIP created cavities that were caused by the porogenic mixture solvents that were created from (acetic acid, methanol) 1:9 respectively, successfully removed by repeated washing for 20 hours, the polymer was dried at room temperature. The maximum adsorption capacity was 11.7797 µmol/g using (0.1) g weight of Glim-MIP. which adhered to the Langmuir isotherm model. A solid-phase extraction (SPE) syringe packed with molecular imprinted polymers (MIPs) was employed to selectively separate and pre-concentrate the Glimepiride in multiple pharmaceutical drugs from several sources. The human serum was based on the use of deionized water to dilute the serum, followed by heating of the serum with methanol. Subsequently, few drops of 1N hydrochloric acid were applied to detect Glimepiride at UV region 274.5 nm by applying the standard addition method.

Optimization of Temperature and Time of Ultrasonic-Assisted Extraction Method on Flavonoid and Antioxidant Activity of Brown Rice from Demak, Indonesia

Brown rice contains a number of bioactive components, such as pigments and flavonoids, which act as antioxidant. Plants widely distribute polar flavonoid compounds, which actively function as antioxidant. Antioxidants are substances that can significantly inhibit or prevent the oxidation of the substrate. The body requires antioxidants to defend itself against attacks by free radicals. The goal of this study was to find the best temperature and time for the Ultrasonic-Assisted Extraction (UAE) method to measure the antioxidant activity and flavonoids in brown rice extract using UV-Visible spectrophotometry. The extract was prepared using the UAE method with 96% ethanol solvent at 45°C and 55°C for 20–30 minutes. Data obtained was statistically analyzed using the one-way ANOVA test. The study found that brown rice extracted with 96% ethanol at 45°C for 20 minutes produced 4.089 mg QE (Quercetin Equivalent)/g of total flavonoids. The antioxidant activity was the lowest, with an IC50 value of 381.102 ppm. The statistical analysis using the one-way ANOVA test revealed that there were no differences in temperature or time optimization that affected the levels of flavonoids and antioxidants. It can be concluded that the 96% ethanol extract of brown rice has the best flavonoid and antioxidant content. The best treatment was at 45°C and 20 minutes of extraction time.

Formulation and Activity of Sunscreen Cream from Ethanol Extract of Calendula officinalis L Flowers

Sunscreen made of natural ingredients is an alternative to protect the skin from excess UV radiation and a substitute for chemical products that have side effects. It was reported that Calendula officinalis L. has flavonoid and saponin metabolite compounds which function as photoprotective agents. This research aims to formulate sunscreen cream and examine the effect of variations in Calendula officinalis L flower extract (5%;7%;10% w/v) on physicochemical properties, stability, and values of the Sun Protecting Factor (SPF) in vitro using UV-Vis spectrophotometry and in vivo using wistar line rat test animals to see the time of formation of Minimum Erythema Dose (MED). It has been proven that variations in the concentration of Calendula officinalis L. extract affected the physicochemical properties, such as pH value, viscosity, spreadability, and adhesion strength. However, the overall results of the physicochemical properties still met the requirements. Variations in extract concentration affected the SPF value. In vitro SPF test showed the minimum protection category for F1, extra protection for F2, maximum protection for F3, and no protection for F0. Meanwhile, the in vivo SPF test showed the minimal protection category for F1, medium protection for F2, extra protection for F3, and no protection for F0.

MINUMAN FUNGSIONAL KAYA ANTIOKSIDAN EKSTRAK DAUN Anredera cordifolia (Ten) Steenis DAN Zingiber officinale Rosc. Var. Rubrum

In the modern era, there are changes in people's lifestyles and worsening environmental conditions which cause people to be exposed to free radicals. Free radicals can be prevented with antioxidant compounds. Binahong leaves and red ginger contain antioxidant compounds in the form of flavonoids, saponins, tannins, alkaloids, polyphenols. The product innovations that can be made wasfunctional drinks. This research aims to determine the quality, flavonoid content and antioxidant activity of functional powder drinks from binahong leaves and red ginger. This research used a quantitative descriptive research methods. Analysis of flavonoid levels and antioxidant activity in powder drinks using UV-Vis spectrophotometry. The organoleptic powder drink in F1 was brownish yellow, in F2 and F3 were yellow. F1, F2 and F3 had a sweet taste and aroma typical of red ginger with a water content of 1.375±0.051%; 1.791±0.073%; and 2.364±0.032%. The pH value in F1, F2, and F3 were 6.071±0.001; 6.274 ± 0.002; and 6.309 ± 0.001. Powdered drinks positively contained flavonoids were respectively of 4.527±0.104%; 4.678±0.050%; and 4.831±0.146%. The IC50 values for F1, F2, and F3 were respectively 97.54±1.73 ppm (strong); 72.69±0.81 ppm (strong); and 46.78±2.20 ppm (very strong). Powder drinks comply with quality requirements according to SNI 01- 4320-1996.

FORMULASI DAN UJI AKTIVITAS ANTIOKSIDAN TEH CELUP BUNGA TELANG (Clitoria ternatea. L) DAN TEH PUTIH (Camellia sinensis)

if there is an increase in free radicals in an uncontrolled amount, more antioxidants are needed to minimize and neutralize the effects of free radicals. These antioxidants can come from consumed food ingredients such as tea bags with a combination of butterfly pea flowers (Clitoria ternatea. L) and white tea (Camellia sinensis) because they have the potential to provide protection from free radicals that can damage body cells. The aim of the study was to determine the levels of antioxidants that would be obtained from combining plants that have high antioxidant activity into a preparation in the form of tea bags. The method used is in vitro using UV-Vis spectrophotometry. Testing of antioxidant activity using the DPPH (1,1-Diphenyl- 2-Picrilhydrazyl) method and data analysis using the Kruskal Walls non-parametric test. In this study the results showed that butterfly pea flowers contain alkaloid compounds, flavonoids, saponins, quinones, and tannins, as well as white tea which contains alkaloids, flavonoids, saponins, quinones, and tannins. The antioxidant activity of butterfly pea flower produced an IC50 value of 262.778 ppm, white tea produced an IC50 value of 14.091 ppm, and formulations of butterfly pea flower and white tea bags that had potential as antioxidants were F1 with an IC50 value of 16.510 ppm. Preparations of teabags of butterfly pea and white tea with a concentration ratio of 50% : 50% are effective as antioxidants and are the preferred formula based on hedonic tests which include color, smell and aroma of teabag preparations.

Direct analysis of hexavalent chromium in water samples by UV-Vis spectrophotometry: Effects of pH and the presence of foreign ions

Direct analysis of hexavalent chromium in water samples by UV-Vis spectrophotometry: Effects of pH and the presence of foreign ions

Photodetector for visible light based on Fe(phen)2(SCN)2 molecule

This paper describes a unique method that uses Iron (phen) molecule [phen: 1,10-phenanthroline] placed on a glass substrate to create a photodetector (PD) that is sensitive to visible light as a heterostructure device. The structural, morphological, and optical properties of the samples were investigated using techniques such as X-ray diffraction (XRD), energy dispersive X-ray spectra (EDX), field emission scanning electron microscopy (FESEM), and UV-Vis spectrophotometry. The photosensitivity of the Iron (phen) /glass PD was evaluated at different bias voltages (5, 10, 15, and 20 V) at wavelength of 510 nm. The photosensitivity values were found to be 58.45, 76.82, 84.9, and 87.83, indicating the PD's ability to generate a measurable electrical response to light stimuli in the visible range. Furthermore, the response and recovery times of the Iron (phen) PD were assessed when exposed to pulsed visible light at a wavelength of 510 nm and bias voltages of 5, 10, 15 and 20 V. The results indicated favorable response and recovery times, suggesting the PD's capability to quickly detect and recover from changes in light intensity. At a bias voltage of 20 V and under illumination with visible light at 510 nm, the Iron (phen) PD demonstrated a maximum current gain of 9.22 and a quantum efficiency (ƞ) of 28.17. These values indicate the PD's ability to amplify the generated electrical current and efficiently convert incident photons into detectable electrical signals. Overall, the fabricated Iron (phen) glass PD exhibited promising photosensitivity, response and recovery times, current gain, and quantum efficiency when exposed to visible light. The findings suggest the potential application of Iron (phen) as a material for visible light photodetection.

Investigating the Impact of Surfactant and Cosolvent on the Polyphenolic Content in Arumanis Mango Leaf Extract (Mangifera indica L.)

The leaf of Mangifera indica L. contains flavonoids and mangiferin which showed positive effects on wound healing of diabetic ulcer. The used of suitable surfactant and co-solvent is required to ensure the high solubility of the active pharmaceutical ingredient (API), thereby optimizing the efficacy. This study aims to determine the ideal surfactant and cosolvent for a thermosensitive hydrogel formula of Mangifera indica leaf ethanol extract. The leaf was fextracted by maceration using 70% ethanol then determined for moisture content. The extract was prepared for solubility tests of flavonoid and mangiferin on surfactants (Kolliphor® EL, Tween® 20, Tween® 80, Miranol® C2M) and co-solvents (Glycerin, PEG 400, and transcutol). Methods for total flavonoids content were Spectrophotometry UV-Vis and mangiferin with RP-HPLC method. The moisture content in the extract is 8.590 ± 0.754%. The surfactant demonstrating the highest capability in flavonoid dissolution is Tween 20 (1863.750 ± 0.838 µgQE/g extract), followed by Tween 80, Kolliphor EL, and Miranol C2M. In the context of co-solvents, PEG 400 (1309.583 ± 0.292 µgQE/g extract) show superior flavonoid dissolution capability, with glycerin and Transcutol following in descending order. Tween 20 and Tween 80 exhibite comparable efficacy in mangiferin dissolution, followed by Miranol C2M and Kolliphor EL. Among co-solvents, Transcutol demonstrate the highest aptitude for mangiferin dissolution, succeeded by PEG 400 and glycerin. This study indicates Tween 20 is a preferable surfactant and PEG 400 was considered as co-solvent to be further used in a thermosensitive gel formula for diabetic ulcer.Â

Algae derived N-doped mesoporous carbon nanoflakes fabricated with nickel ferrite for photocatalytic removal of Congo Red and Rhodamine B dyes

A hydrothermal approach was employed to synthesize nickel ferrite (NiFe2O4) nanoparticles and its composite (NiFe2O4–NCF) with N-doped mesoporous carbon nanoflakes (NCF) where NCF acts as the catalytic support. The N-doped carbon nanoflakes were derived by pyrolyzing algae under Nitrogen atmosphere. These prepared materials were later probed with XRD, FESEM, TEM, BET, VSM, PL and UV–Vis spectrophotometry for their structural, morphological, magnetic and optical properties. The materials were used as photocatalysts to degrade two harmful textile dyes viz. Congo Red (CR) and Rhodamine B (RhB) under visible light at room temperature. Under optimized conditions, the pristine NiFe2O4 nanoparticle could degrade 95.34% and 98.24% CR and RhB respectively within 70 min while, the NiFe2O4–NCF nanocomposite showed degradation efficiency of 96.51% and 98.83% within 40 and 35 min of light irradiation respectively for CR and RhB dyes. The radical scavenging experiments indicated that electron and hole are the main reacting species that initiate the degradation of the dyes against the catalyst.

Preparation of Green Silver Nanoparticles and Eco-Friendly Polymer-AgNPs Nanocomposites: A Study of Toxic Properties across Multiple Organisms.

This article focuses on the eco-friendly (green) synthesis of silver nanoparticles (AgNPs) and their incorporation into a polymer matrix. For AgNPs synthesis, Lavandula angustifolia (lavender) leaf extract was used as a reducing and stabilizing agent, and as a silver precursor, AgNO3 solution with different concentrations of silver (50, 100, 250, and 500 mg/L) was used. Prepared AgNPs colloids were characterized using UV-vis spectrophotometry, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The spherical morphology of AgNPs with an average size of 20 nm was confirmed across all samples. Further, the antimicrobial properties of the AgNPs were evaluated using the disk diffusion method on algae (Chlorella kessleri) and the well diffusion method on bacteria (Staphylococcus chromogenes, Staphylococcus aureus, and Streptococcus uberis), along with root growth inhibition tests on white mustard (Sinapis alba). Polymer composite (PVA-AgNPs) was prepared by incorporation of AgNPs into the polymer matrix. Subsequently, non-woven textiles and thin foils were prepared. The distribution of AgNPs within the nanocomposites was observed by scanning electron microscopy (SEM). Antibacterial properties of PVA-AgNPs composites were analyzed on bacteria Streptococcus uberis. It was found that not only AgNPs showed good antimicrobial properties, but toxic properties were also transferred to the PVA-AgNPs nanocomposite.

The Potential of Daruju Leaf Extract (Acanthus Ilicifolius) as a Bioreductor in the Synthesis of Silver Nanoparticles and Antibacterial Activity Test

Silver nanoparticles had been synthesized through the bioreduction process using daruju (Acanthus ilicifolius) leaf extract as a bioreductant. The variation of the formula used is a mixture of daruju leaf extract with a 0.01 M AgNO3 solution with volume ratios of 2:1, 1:1, 1:2, and 1:3. The research results show that UV-Visible spectrophotometry confirmed that a volume ratio of 1:1 is the optimum formula with an absorption value of 2.346 at the maximum wavelength 440 nm. Synthesis of silver nanoparticles with daruju leaf extract has a strong inhibition zone about 10.42 mm. Proving that the synthesis of silver nanoparticles with extract daruju leaf can be used as an antibacterial agent against E.coli bacteria.

A novel univariate interpolation and bivariate regression hybrid method application to biodegradation of bisphenol A diglycidyl ether using laccases from Geobacillus stearothermophilus and Geobacillus thermoparafinivorans strains.

Bisphenol A diglycidyl ether (BADGE), a derivative of the well-known endocrine disruptor Bisphenol A (BPA), is a potential threat to long-term environmental health due to its prevalence as a micropollutant. This study addresses the previously unexplored area of BADGE toxicity and removal. We investigated, for the first time, the biodegradation potential of laccase isolated from Geobacillus thermophilic bacteria against BADGE. The laccase-mediated degradation process was optimized using a combination of response surface methodology (RSM) and machine learning models. Degradation of BADGE was analyzed by various techniques, including UV-Vis spectrophotometry, high-performance liquid chromatography (HPLC), Fourier transform infrared (FTIR) spectroscopy, and gas chromatography-mass spectrometry (GC-MS). Laccase from Geobacillus stearothermophilus strain MB600 achieved a degradation rate of 93.28% within 30 min, while laccase from Geobacillus thermoparafinivorans strain MB606 reached 94% degradation within 90 min. RSM analysis predicted the optimal degradation conditions to be 60 min reaction time, 80°C temperature, and pH 4.5. Furthermore, CB-Dock simulations revealed good binding interactions between laccase enzymes and BADGE, with an initial binding mode selected for a cavity size of 263 and a Vina score of -5.5, which confirmed the observed biodegradation potential of laccase. These findings highlight the biocatalytic potential of laccases derived from thermophilic Geobacillus strains, notably MB600, for enzymatic decontamination of BADGE-contaminated environments.

Application of Turbiscan Lab® to study the mechanism of fining in red wine using a specific yeast protein extract: A comparison with gelatine

Fining of wines using proteins is a standard practice in the winemaking process. Gelatine is a common fining agent used for red wines. However, the consumer demand for wines that are free of animal-derived products has reinforced the search for alternative protein sources such as yeast origin as the latter is originally present in wine. In 2012, the International Organization of Vine and Wine (OIV) authorized yeast protein extract (YPE) as a processing aid for the fining of musts and wines (OIV-Eno 452–2012). The present work aimed at better understanding the fining mechanisms of a specific YPE, to evaluate the part played by interactions in solution with polyphenols, but also at the interfaces with suspended particles. Polyphenols from the soluble phase of red wine were separated from the suspended particles by centrifugation, and these particles were resuspended in a wine model solution. Interactions with YPE were studied with each fraction separately through static multiple light scattering (SMLS) using the Turbiscan Lab® apparatus and optical microscopy. The impact on wine color and astringency was assessed by UV–visible spectrophotometry and BSA assay test. Faster aggregation and sedimentation kinetics were observed with gelatine than with YPE, but the levels of clarification and lees were similar for both fining agents after a couple of hours (4 h maximum). Gelatine resulted in higher tannin and pigment removal, likely to decrease astringency but also derived pigments involved in red wine color stability. Meanwhile, the impact of the YPE was moderate, likely to modulate astringency while preserving wine color and structure. In addition to interacting directly with polyphenols in solutions such as gelatine, YPE exhibited the additional ability to trap particles and promote their sedimentation in the absence of tannins. This double performance of the YPE used in this work, is likely to guarantee an effective fining of red wines as well as for low tannin content matrices such as rosé and white wines.

Evaluation of the Effect of Different Extraction Temperatures on the Synthesis of Silver Nanoparticles from Ocimum basilicum (Basil) Plant

The eco-friendly green synthesis of silver nanoparticles (AgNPs) using Ocimum basilicum (basil) extract at varying extraction temperatures (40°C, 60°C, 80°C, 100°C) was investigated to determine the optimal conditions for nanoparticle formation. Analysis methods such UV-Vis spectrophotometry, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and TransmissionElectron Microscopy (TEM) confirmed the crystalline, spherical nature of AgNPs and identified phytochemicals acting as capping and reducing agents. Notably, the extraction temperature was found to influence both the DPPH radical scavenging activity and the structural properties of AgNPs. According to TEM analysis results, it was observed that high extraction temperatures increased the nanoparticle formation efficiency but created a wide size distribution. The crystallite sizes, calculated using the Scherrer equation, for AgNPs synthesized at different extraction temperatures, were determined to be 12.45 nm, 18.77 nm, 17.76 nm, and 16.03 nm, respectively. The hydrodynamic sizes of the AgNPs were found to range between 158.1 and 333.7 nm. The study highlights the critical role of extraction temperature in the synthesis process, suggesting 40°C as the optimal temperature for achieving efficient and environmentally friendly synthesis of AgNPs with enhanced biological activities.

Analisis Kandungan Protein pada Susu Sapi Perah Kemasan dari Peternakan Desa Gunung Perak Sinjai Barat

Humans require food and beverages that serve as building materials, regulators, and sources of energy. Protein is an essential component that functions in tissue maintenance, formation of essential body compounds, antibody production, and maintaining bodily balance. However, the protein content in packaged dairy cow milk can decrease over storage time after packaging, which may affect the nutritional value received by consumers. This study aims to identify and analyze changes in protein levels in packaged dairy cow milk over three days after packaging. The research method used is UV-VIS spectrophotometry with a Genesys 10-S spectrophotometer to measure the protein content in dairy cow milk samples taken from Gunung Perak Village, Sinjai Barat Subdistrict, Sinjai Regency. The results showed that the protein content of the milk one day after packaging was 0.027%, two days after packaging was 0.021%, and three days after packaging was 0.019%. This decrease in protein levels indicates that the duration of storage after packaging negatively affects the protein quality of the milk. The implication of these research findings is the need for special attention in the storage and distribution process of packaged dairy cow milk to maintain its protein content, ensuring that the nutritional value received by consumers remains optimal. Further research with different methods is recommended to obtain more in-depth information about the factors influencing changes in protein levels in the milk.

Immobilization of Thiol-Modified Horseradish Peroxidase on Gold Nanoparticles Enhances Enzyme Stability and Prevents Proteolytic Digestion.

The specificity and efficiency of enzyme-mediated reactions have the potential to positively impact many biotechnologies; however, many enzymes are easily degraded. Immobilization on a solid support has recently been explored to improve enzyme stability. This study aims to gain insights and facilitate enzyme adsorption onto gold nanoparticles (AuNPs) to form a stable bioconjugate through the installation of thiol functional groups that alter the protein chemistry. In specific, the model enzyme, horseradish peroxidase (HRP), is thiolated via Traut's reagent to increase the robustness and enzymatic activity of the bioconjugate. This study compares HRP and its thiolated analog (THRP) to deduce the impact of thiolation and AuNP-immobilization on the enzyme activity and stability. HRP, THRP, and their corresponding bioconjugates, HRP-AuNP and THRP-AuNP, were analyzed via UV-vis spectrophotometry, circular dichroism, zeta potential, and enzyme-substrate kinetics assays. Our data show a 5-fold greater adsorption for THRP on the AuNP, in comparison to HRP, that translated to a 5-fold increase in the THRP-AuNP bioconjugate activity. The thiolated and immobilized HRP exhibited a substantial improvement in stability at elevated temperatures (50 °C) and storage times (1 month) relative to the native enzyme in solution. Moreover, HRP, THRP, and their bioconjugates were incubated with trypsin to assess the susceptibility to proteolytic digestion. Our results demonstrate that THRP-AuNP bioconjugates maintain full enzymatic activity after 18 h of incubation with trypsin, whereas free HRP, free THRP, and HRP-AuNP conjugates are rendered inactive by trypsin treatment. These results highlight the potential for protein modification and immobilization to substantially extend enzyme shelf life, resist protease digestion, and enhance biological function to realize enzyme-enabled biotechnologies.

Preparation of nanocellulose/reduced graphene oxide matrix loaded with cuprous oxide nanoparticles for efficient catalytic reduction of 4-nitrophenol.

The paper reports on the preparation of cellulose nanocrystals/reduced graphene oxide matrix loaded with cuprous oxide nanoparticles (CNC/rGO-Cu2O) through a simple solvothermal method and its application for 4-nitrophenol reduction to 4-aminophenol using sodium borohydride. The CNC/rGO-Cu2O nanocomposite was formed chemically by first mixing CNC and graphene oxide (GO) followed by complexation of the negatively charged functional groups of CNC/GO with Cu2+ ions and subsequent heating at 100°C. This resulted in the simultaneous reduction of GO to rGO and the formation of Cu2O nanoparticles. The as-elaborated nanocomposite was firstly characterized using different techniques such as atomic force microscopy, scanning electron microscopy, transmission electron microscopy, UV-Vis spectrophotometry, Raman spectroscopy and x-ray photoelectron spectroscopy. Then, it was successfully applied for efficient catalytic reduction of 4-nitrophenol to 4-aminophenol using sodium borohydride: the reduction was completed in about 6 min. After eight times use, the catalyst still maintained good catalytic performance. Compared to CNC/rGO, rGO/Cu2O and free Cu2O nanoparticles, the CNC/rGO-Cu2O nanocomposite exhibits higher catalytic activity even at lower copper loading.

Antifungal screening of silver nanoparticles biosynthesized by Aliinostoc oryzae against plant pathogenic fungi

Metallic nanoparticles exhibit exceptional antifungal characteristics and are regarded as a feasible substitute for the control of diverse fungus species. Cyanobacteria have received significant recognition as nanobiofactories across all identified taxa owing to their remarkable ability to assimilate toxins from their environment. Consequently, cyanobacteria-mediated metal nanoparticle synthesis represents an innovative strategy for biological regulation. The present investigation assessed the effectiveness of silver nanoparticles (AgNPs) manufactured using Iranian cyanobacteria, Aliinostoc oryzae, as fungus inhibitors against plant pathogens. For this purpose, the cyanobacterial strain was cultured in BG-110, medium and AgNPs were synthesized by the wet biomass method. The AgNPs were then characterized by UV–visible spectroscopy, DLS, zeta potential, field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction tests. Afterwards, the antifungal activities of fabricated nanoparticles were tested against fungal strains of Botrytis cinerea, Alternaria alternate, Colletotrichum gloeosporioides, Fusarium oxysporum, Phytophthora capsici, Pythium ultimum, and Rhizopus stolonifera. The results of UV–vis spectrophotometry confirmed the AgNP formation with a color change to dark brown at a wavelength range of 430–432 nm. Morphological examination through the Field Emission Scanning Electron Microscope (FESEM) indicated irregular and spherical shapes. X-ray diffraction (XRD) results showed a cubic crystalline structure with a crystallite size of approximately 20 nm. The zeta potential and electrophoretic mobility of the nanoparticles were −33.67 mV and 0.35 Vs/cm2, respectively. Fourier-transform infrared spectroscopy (FTIR) analysis identified a sharp and intense peak at 538 cm−1, corresponding to the stretching vibration of silver nanoparticle bonds. Based on the antifungal activity results, Pythium ultimum had the largest growth inhibition zone. On the other hand, Colletotrichum gloeosporioides and Alternaria alternate had the smallest inhibition zones. These findings demonstrate the ability to characterize and test AgNPs produced by Iranian cyanobacteria for their antifungal activity.

Impact of zinc concentration and annealing temperature on the structural, optical, and photoelectrochemical properties of nickel oxide thin films synthesized by electrodeposition method

In this study, Zinc (Zn)- doped nickel oxide (NiO) thin films were fabricated via the electrodeposition method. The synthesized films were created with different concentrations of Zn (2 %, 4 %, 6 %, and 8 %) after that annealed at two different temperatures (300 °C and 500 °C). The prepared samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy (RAM), UV–vis spectrophotometry, photocurrent (PC), photoluminescence (PL), electrochemical impedance spectroscopy (EIS), Energy-Dispersive X-ray spectroscopy (EDX), photocurrent (PC), and Mott-Schottky (MS) analysis. XRD patterns indicate that Zn: NiO thin films have a cubic phase, with the (111) direction as the preferred orientation. Various structural parameters such as dislocation density, stacking fault, lattice strain, and crystallite size have been determined. The presence of Zn doping in NiO has been confirmed by EDX analysis. The EDX mapping of elements revealed the uniform distribution of Ni, Zn, and O in the sample. The optical transmittance and absorbance were analyzed using a UV–vis spectrophotometer. The lowest transmittance values were found for 8 % Zn: NiO thin films annealed at 300 °C and 500 °C. The absorption edge corresponding to pure NiO-300 °C and NiO-500 °C has been observed at 300 and 320 nm, respectively. The band gap energy (Eg) decreased to 3.88 eV for 8 %Zn: NiO (300 °C) and 3.71 eV for 8 %Zn: NiO (500 °C). The Raman analysis showed three distinct peaks at 590 cm−1, 705 cm−1, and 1172 cm−1, which correspond to the vibration of Ni—O bonds. The SEM results indicated that increasing the doping concentration and annealing temperature resulted in larger grain sizes in the manufactured samples. Furthermore, the PL spectra analysis of the synthesized films revealed two distinct emission peaks at around 400 and 490 nm. PC analysis confirmed the p-type conductivity of manufactured arrays. From MS measurements, the highest carrier concentration (NA) values of 8.81×1018 cm−3 and 9.41×1019 cm−3 were obtained for 8 %Zn: NiO (300 °C) and 8 %Zn: NiO (500 °C), respectively. EIS analysis confirmed the highest conductivity and enhanced electrochemical activity for 6 % Zn: NiO (500 °C) and 8 % Zn: NiO (300 °C). These results suggest that Zn-doped NiO is suitable for optoelectronic applications.