Visible Spectroscopy Research Articles

A 36-nucleus silver-thiolate cluster encapsulating double sulfates and co-protected by cyclen

New type of cyclic multi-dentate ligand named, Cyclen (1,4,7,10-tetraazacyclododecane, [12]aneN4), was successfully introduced onto the surface of a 36-nucleus double sulfates templated silver-thiolate cluster [(SO4)2@Ag36(SPhtBu)24(cyclen)4(CF3CO2)6(OH)2] (1). The nanocluster was investigated and characterized by single-crystal X-ray crystallography (SXRD), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), thermogravimetry (TG), ultraviolet−visible (UV) spectroscopy, and photoluminescence (PL). The cluster shows very good solution stability in four different solvents and excellent thermal stability in the solid-state. It shows orange-red emission in EtOAc/THF/CH2Cl2/CHCl3 at 77 K. The lifetime of 1 in four different solvents is over 140 μs, and the highest quantum yield of 1 is 25.46 %. The nanocluster shows temperature-dependent photoluminescence properties in different solvents, which make them potential candidates in the fields of optical devices for future applications.

Optimization, imaging and LHE analysis of magnesium oxide nanoparticles synthesized with carambola extract as natural dye sensitizer

This work explores the enhancement of dye-sensitized solar cells (DSSCs) by using magnesium oxide nanoparticles (MgO NPs) that have been green-synthesized, with carambola extract acting as a natural dye sensitizer. Green synthesis minimizes the negative effects of traditional synthesis methods on the environment by providing a sustainable and ecologically friendly way to produce MgO NPs. To increase their effectiveness in DSSC applications, the synthesized nanoparticles underwent optimization. The morphology and size distribution of MgO NPs were characterized by scanning electron microscopy (SEM), which revealed spherical forms with a consistent size distribution. The crystalline nature of the MgO NPs was verified by X-ray diffraction (XRD), which revealed distinctive peaks that correspond to the bulk MgO crystal planes. A band gap of 3.5 eV, appropriate for UV region absorption, was found using UV–visible spectroscopy. FT-IR (Fourier-transform infrared) spectroscopy revealed information about their molecular compositions. Positive electronic characteristics, such as a negative total energy change (ΔE_T) and a high electrophilicity index (ω), which indicates effective charge transfer, were found through computational analysis. The light harvesting efficiency (LHE) value of 0.00459 signifies optimal light absorption capability by the dye molecule. The outcomes show that MgO NPs that have undergone green synthesis have the potential to be efficient and stable sensitizers for DSSCs. In addition to highlighting the significance of green synthesis techniques in nanomaterial research for renewable energy applications, this work advances the development of efficient and sustainable solar energy systems.

Early Detection of Cassava Vascular Bacteriosis (Xanthomonas Axonopodis pv. Manihotis) by Visible Near-infrared Spectroscopy Before the Appearance of Critical Symptoms

Cassava is a crucial crop for food and nutritional security. It is an important source of carbohydrates in African countries. Cassava crops can sometimes be infected by leaf diseases, affecting overall production and reducing farmers' incomes. Early detection is therefore essential to reduce the impact of these diseases. Light reflections from leaves are known to convey information about plant health. In this study, healthy and inoculated cassava were detected from the reflections obtained from the leaves using a USB 4000 spectrometer with a spectral range of (350-1050) nm. Artificial neural networks (ANNs) and nearest neighbours (KNNs) were used with principal components and vegetation indices as input for classification. Various performance metrics, i.e. Precision, Recall, Accuracy and F1_score for KNN, Accuracy, RMSE and R2 for ANN were calculated to evaluate the different established models. Using the principal components (PC1, PC2) we obtained the best models with the ANNs with the following metrics (R2=0.9678; RMSE=0.0146; Accuracy =98.30%) for the variety IM 84 and (R2=0.9291; RMSE=0.0354 Accuracy=91.30%) for the Yacé variety. With vegetation indices, the best performing models were obtained with KNN whose input parameters are RatiodRE_703 ((Accuracy =92.50% and F1-score=0.9449) and fWBI ((Accuracy =90% and F1-score=0.9326) for Yacé and vog 3 (Accuracy=100% and F1-score=1), DD (Accuracy=100% and F1_score=1) and dNIRmin920_980 (Accuracy=95% and F1_score=0.9373) for the IM 84. Overall, the results showed that leaf spectral reflectance can be used successfully for the early detection of cassava bacterial blight.

An insight for the interaction of Aceclofenac with hemoglobin using spectroscopic, electrochemical and in silico approaches

The interactions between protein and ligand are crucial to practically every biological function in the body, and investigations of these interactions are critical from the perspective of logical medication development. In this work, several biophysical methods like UV–Visible spectroscopy, fluorescence spectroscopy, and in-silico studies have been explored to examine the interaction between aceclofenac and haemoglobin. Spectrofluorimetric data confirmed the static nature of the protein quenching mechanism caused by the medication. ΔG for the formation of the complex via the interaction was found to be − 12.65 kJ/mol. Molecular docking showed a strong interaction between aceclofenac and hemoglobin with a binding energy of − 31.79 kJ/mol. Further, molecular dynamics simulations using Gromacs were run to investigate the stability of the protein with and without aceclofenac, and the ΔG for the formation of the complex (hemoglobin-aceclofenac) is − 105.09 kJ/mol with an error of 13.51 kJ/mol. Spectroscopic and in-silico calculations indicate the feasible binding of the aceclofenac with hemoglobin. Further, the interaction of haemoglobin with aceclofenac was studied by cyclic voltammetry.Graphical

Copper selenide as a facile nanomaterial for triboelectric nanogenerator: Self-powered Braille code keyboard

The development of triboelectric nanogenerators (TENGs) for sustainable energy harvesting has garnered significant interest, especially in integrating advanced materials to enhance device performance and exploring applications. Herein, the present study investigates the use of copper selenide (Cu2Se) as a robust material for TENGs fabrication. Cu2Se nanorods are synthesized using a facile hydrothermal method and subsequently embedded in a polyvinyl alcohol (PVA) matrix to form a nanocomposite, which is then utilized as tribopositive film. The procured Cu2Se and nanocomposites with varying filler quantities (0.1, 0.2, 0.4, and 0.8 wt%) are analyzed using powder X-ray diffraction, scanning electron microscopy, dielectric measurements, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy to evaluate their structural, morphological, dielectric, and optical properties, and their impact on TENG performance. Interestingly, the device with 0.2 wt% Cu2Se generated peak-to-peak voltage and current of 394.35 V and 83.45 µA respectively, which is about 2.5- and 41-times higher output compared to pristine PVA-TENG. Integrating Cu2Se as filler enhances charge generation, transfer, and retention, due to increased surface roughness, and ability to facilitate better charge separation within the polymer matrix leading to more efficient energy conversion in TENGs. In practical demonstration, the optimized PVA@ Cu2Se-TENG is employed as a self-powered Braille keyboard to generate electrical signals from mechanical interactions, offering a promising solution for energy-efficient, user-friendly Braille technology. Thus, the current study highlights the synergistic effects of integrating Cu2Se with polymer, resulting in enhanced triboelectric performance for innovative energy harvesting applications and self-powered sensory devices.

Highly efficient dip catalysts using bacterial cellulose impregnated with self-crosslinked glycol chitosan and silver nanoparticles for 4-nitrophenol reduction

The application of environmentally friendly and sustainable catalysts requires efficient and safe preparation methods using cheap and renewable materials. Although many metal nanoparticles (NPs) have low colloidal stability, they are still very effective as catalysts. Using a straightforward method, we developed a bacterial cellulose–glycol chitosan–silver (BC–GCS–Ag) nanocomposite, by introducing both AgNPs and self-crosslinked GCS within the BC network. Self-crosslinking of GCS occurred during the formation of AgNPs by employing the glycol moieties for reduction to produce aldehyde functionalities, thereby forming Schiff's base bonds within the GCS structure. Using GCS, well-defined AgNPs within the BC matrix. The formation of AgNPs and the self-crosslinking of GCS were characterized using UV–visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results showed that spherical AgNPs with a mean diameter of 10 nm exhibited a well-organized structure within the BC–GCS matrix. The BC–GCS–Ag nanocomposite was applied as dip catalyst for the reduction of 4-nitrophenol (4NP) to 4-aminophenol (4AP), chosen as a model reaction. The results showed that the catalytic reaction was completed within 4 min, with high reusability (10 times) and without loss of catalyst. The reaction followed pseudo-first-order kinetics with a high rate constant of 0.582 min−1. Therefore, the BC–GCS–Ag dip catalyst is an attractive alternative for environmentally friendly and sustainable catalysis, owing to its exceptional catalytic performance, high recyclability, and stability, as well as the minimal environmental footprint of the supporting materials.

Enhanced photoelectrochemical CO2 reduction activity towards selective generation of alcohols over CuxO/SrTiO3 heterojunction photocathodes

Photoelectrochemical reduction (PECR) of CO2 to value-added chemicals and fuels will reduce the dependency on fossil fuels, also it will solve environmental issues that arise due to greenhouse gases. A heterojunction of CuxO/SrTiO3 with varying post-annealing temperature ranges from 300 to 600 °C (CS300-600) was synthesized by overlying the spin-coated SrTiO3 on electrodeposited Cu2O over the FTO glass substrate. The synthesized photoelectrode's crystallinity and phase formation significantly varied by varying the post-annealing temperature, which was characterized via XRD and Raman spectroscopy. Optical, morphological, type of heterojunction formation and elemental surface oxidation states of photoelectrodes were studied through UV–visible DRS spectrum, FE-SEM, and XPS analysis respectively. Electrocatalytic analysis such as Linear Sweep Voltammetry (LSV), and Electrochemical Impedance Spectrometry (EIS) was employed, thus it conforms to the highest photocurrent density (−1.38 mA/cm2 at −0.6V vs. Ag/AgCl), and low charge transfer resistance (RCT=0.412 kΩ) at the electrode-electrolyte interfaces for CS500 photoelectrode as compared to others photoelectrodes. PECR of CO2 to liquid product formation was evaluated by applying different potential ranges (0 to −0.6 V vs. Ag/AgCl). Highest methanol formation of 48.69 μmol.cm−2hr−1, which is approximately 9 times enhanced as compared to the pure Cu2O (5.62 μmol.cm−2hr−1) photoelectrode at 0 V vs Ag/AgCl for CS500 heterojunction. Optimization of overlaying SrTiO3 synthesis temperature for crystallization formation on Cu2O and applied photoelectrode potential findings could pave the way for designing other new heterojunction types for selective liquid alcohol production.

In vitro cytotoxicity assessment of biosynthesized Apis mellifera bee venom nanoparticles (BVNPs) against MCF-7 breast cancer cell lines

In this work, we reported the synthesis of honey bee (Apis mellifera) venom-derived nanoparticles via a hydrothermal method. This method not only ensures the preservation of the bee venom’s bioactive components but also enhances their potential stability, thus broadening the scope for their applications in the biomedicinal field. The synthesis method started with the homogenization suspension of bee venom, followed by its hydrothermal process to synthesize bee venom nanoparticles (BVNPs). The successful synthesis of BVNPs was characterized using various characteristic techniques such as Ultraviolet–visible (UV–Vis) spectroscopy, Fourier Transforms Infrared (FTIR) Spectroscopy, Zeta Potential (ZP), Liquid Chromatography-Mass Spectrometry (LCMS), and Transmission Electron Microscopy (TEM). The synthesis of BVNPs through biosynthesis is shown by the visible violet-brown color development at 347 nm by UV–Vis spectroscopy. FTIR analysis revealed the presence of several functional groups in the BVNPs, including alcohols (–OH), phenols (C6H5–), carboxylic acids (–COOH), amines (–NH2, –NH–), aldehydes (–CHO), ketones (–CO–), nitriles (–CN), amides (–CO–N–), imines (–CNH–), esters (–COO–), and polysaccharides. These functional groups, as confirmed by their specific stretching and bending vibrational modes, contribute to the diverse biological activities of BVNPs, including cytotoxicity against MCF-7 breast cancer cells. The ZP of the BVNPs indicated good colloidal stability at − 45 mV. LCMS analysis confirmed the presence of major bioactive molecules, including melittin & apamin and TEM analysis shows the BVNPs exhibited a quasi-spherical shape with good dispersion, the average size was approximately 25 nm, with some being smaller (quantum dots) and interplanar spacing of 0.236 nm indicated a highly ordered crystalline structure. Moreover, the anticancer efficacy of the BVNPs was ascertained through in vitro assays against MCF-7 breast cancer cells, showing a dose-dependent cytotoxic effect. The findings of this study underscore the viability of hydrothermal synthesis in producing biologically active and structurally stable BVNPs, with a significant potential for anticancer activities.Graphical

Identifying the Vertical Stratification of Sediment Samples by Visible and Near-Infrared Spectroscopy

Vertical stratification in marine sediment profiles indicates physical and chemical sedimentary processes and, thus, is the first step in sedimentary research and in studying their relationship with global climate change. Traditional technologies for studying vertical stratification have low efficiency; thus, new technologies are highly needed. Recently, visible and near-infrared spectroscopy (VNIR) has been explored to rapidly determine sediment parameters, such as clay content, particle size, total carbon (TC), total nitrogen (TN), and so on. Here, we explored vertical stratification in a sediment column in the South China Sea using VNIR. The sediment column was 160 cm and divided into 160 samples by 1 cm intervals. All samples were classified into three layers by depth, that is, 0–50 cm (the upper layer), 50–100 cm (the middle layer), and 100–160 cm (the bottom layer). Concentrations of TC and TN in each sample were measured by Elementa Vario EL III. Visible and near-infrared reflectance spectra of each sample were collected by Agilent Cary 5000. A global model and several classification models for vertical stratification in sediments were established by a Support Vector Machine (SVM) after the characteristic spectra were identified using Competitive Adaptive Reweighted Sampling. In the classification models, K-means clustering and Density Peak Clustering (DPC) were employed as the unsupervised clustering algorithms. The results showed that the stratification was successful by VNIR, especially when using the combination of unsupervised clustering and machine learning algorithms. The correct classification rate (CCR) was much higher in the classification models than in the global model. And the classification models had a higher CCR using K-means combined with SVM (94.8%) and using DPC combined with SVM (96.0%). The higher CCR might be derived from the chemical classification. Indeed, similar results were also found in the chemical stratification. This study provided a theoretical basis for the rapid and synchronous measurement of chemical and physical parameters in sediment profiles by VNIR.

Exploring Structural and Optical Properties of Nanoparticles of Barium Titanate and Iron doped Barium Titanate and Their Potential Application in Antibacterial Activity

Background: Barium Titanate (BaTiO3) is a good candidate for a variety of applications due to its excellent dielectric, ferroelectric and piezoelectric properties. Methods: Pure and doped Barium Titanate (BTO) nanoparticles have been synthesized by the sol-gel method. Barium hydroxide octahydrate (Ba (OH)2.8H2O) and titanium (IV) iso-propoxide (Ti {OCH[CH3]2}4) were used as starting materials. Apart from pure Barium Titanate nanoparticles, Fe-doped BaTiO3 nanoparticles of three different concentrations: 0.1, 0.2 and 0.3 in mol% were prepared and characterized using X-ray diffraction (XRD), UV visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR). Results: From the X-ray diffraction pattern, the particle size was found to be varied in a range of 17-25nm. By using UV visible spectroscopy it was observed that the band gap energy of pure BaTiO3 NP is 3.2eV. As the pure BaTiO3 nanoparticles are doped with 0.1% Fe, the band gap reduces to 3.175eV. For BaTiO3 doped with 0.2% and 0.3% Fe, the band gap energy values are 2.709 and 2.652 respectively. FTIR spectra were used to analyze the vibrational modes of BaTiO3. From the result obtained from FTIR, we can see that the absorption spectrum ranges from 450cm-1-4000cm-1. The prominent peak of pure BaTiO3 is at 500cm-1 which is due to the vibration of the Ti-O band in crystal lattice. For BaTiO3 doped with Fe2O3, the wave number of the absorption peak is shifted from 500cm-1 in pure BaTiO3. The antibacterial studies were conducted on Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. Conclusion: Both pure and iron-doped Barium Titanate showed significant antibacterial properties, confirming the antibacterial property of Barium Titanate nanoparticles.

Detection of piperine content in black pepper using a molecular imprinted poly(N,N-dimethylacrylamide) embedded graphite electrode: A machine learning based prediction approach

The paper presents a molecular imprinted graphite electrode for selective and sensitive detection of piperine (1-Propylpiperidine) in Piper nigrum (black pepper). Poly(N,N-dimethylacrylamide) (PDMAM) was utilized as a functional monomer directing polymerization of uniform molecularly imprinted polymer (MIP) layers on the surface of the graphite layer using ethylene glycol dimethacrylate (EGDMA) as cross-linker with piperine (PIP) as template molecules. The formation of imprinting, non-imprinting, and elution of analytes within the polymer matrix were studied by field emission scanning electron microscope (FESEM), Fourier transform infrared (FTIR), UV–visible (UV–Vis) and X-ray photoelectron spectroscopy (XPS). The electrochemical response of piperine was evaluated through differential pulse voltammetry (DPV) using a PDMAM-MIP@G electrode that showed an oxidation peak at 1.25 ± 0.15 V. Under optimized experimental conditions, DPV peak currents were linear over two concentration ranges (0.001–1 µM and 1–200 µM). A limit of detection (LOD) was found to be 0.0006 µM. Developed electrode yielded high selectivity, sensitivity (12.92 µA/µM (lower linear range) and 0.33 µA/µM (upper linear range)), promising reproducibility, long-term stability (3.85 % decrease in response over 28 days), and interference immunity. The developed PDMAM-MIP@G electrode was applied to real samples using four branded pepper powder procured from local market and the sensor data was recorded. A convolutional neural network (CNN) driven prediction model has been proposed to predict the piperine concentration. Among the four CNN models tested, the best model, averaged over 50 runs, achieved a mean absolute error (MAE) of 0.268, a mean prediction error of 2.35 %, and a R-squared value of 0.93 on the testing set when compared with reference values obtained from reverse-phase high-performance liquid chromatography (RP-HPLC).

Structural, morphological and optical properties of the La2W2O9/Fe2O3 composite for UV-shielding applications

Currently, research has been conducted on the individual oxides La2W2O9 and Fe2O3 but not on its composite form. Using a solid-state reaction technique, a La2W2O9/Fe2O3 composite was created. A particular calcination cycle was followed by mixing the raw precursors. Scanning electron microscopy (SEM) was used to investigate the morphological microstructure, and X-ray diffraction (XRD) was used to examine the structural characteristics. The thermal and gravimetric properties were examined via differential thermal analysis (DTA) and thermogravimetric analysis (TGA). The optical characteristics were investigated via UV–visible spectroscopy, which investigated included the transmittance, absorbance, absorption coefficient, band gap (Eg), penetration depth (β), Urbach energy (EU), refractive index, optical conductivity, and dielectric function. These findings indicate that the optical properties improved after the addition of Fe2O3 compared with those of pure La2W2O9. The La2W2O9/Fe2O3 composite holds promise as a prospective material for use in the fields of sunscreen products, UV shielding or solar filtration.

Eco-Friendly Green Synthesis of Chromium Oxide Nanoparticles and Their Characterization and Application

In recent years the nanoparticle design synthesis methods conducted by plants replaced the traditional chemical procedures of nanoparticles preparations. This study demonstrates the environmental kindly preparations of chromium oxide nano particles (Cr2O3-NPs) using leaf extract of Mentha pulegium plant. The obtained Cr2O3-NPs was characterized by Ultra Violet /Visible spectroscopy, Fourier Transform Infra-Red (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectrophotometer (EDX) and X-ray diffraction studying. The presence of the Sharp peak at 462 nm in the Ultraviolet/Visible spectrum and the color changed by surface plasma resonance explains that Cr2O3-NPs is formed. The presence of oxygen and chromium in Cr2O3-nanoparticles is reported by EDX spectrum, which was found to consist of 32.57% Cr and 44.41% O, confirming the high purity of the Cr2O3-NPs powder. Since Scan Electron Microscope studying reported an irregular round morphology shape. In addition, X-ray diffraction studying suggested their crystalline feature by the characteristic peaks at 2θ= 24.3°, 33.5°, 36.2°, 41.5°, 50.3°, 54.8°, 63.4°, and 65.2°, respectively. The average crystallite size for Cr2O3-NPs was found to be 58 nm. The photo catalytic activity of green synthesized chromium oxide-NPs was also analyzed.

Green synthesized Cr2O3/Bi2O3 nanocomposites for gamma ray shielding

The quest for advanced materials in gamma radiation shielding has spurred the exploration of environmentally friendly, nanotechnology-based approaches. This study introduces a novel synthesis of Cr2O3/Bi2O3 nanocomposites (NCs) using the solution combustion method, with Aloe vera extract serving as a natural reducing agent. Comprehensive analytical characterization of the synthesized NCs was conducted using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and ultraviolet–visible (UV–Vis) spectroscopy. The gamma radiation shielding properties of the Cr2O3/Bi2O3 NCs are evaluated using a NaI(Tl) detector connected to a multichannel analyzer. Key shielding parameters, including mass attenuation coefficients, mean free path, half-value layer, tenth-value layer, energy buildup factor, and radiation protection efficiency, indicate that Cr2O3/Bi2O3 NCs are highly effective in gamma radiation shielding. The results demonstrated the feasible shielding performance of these nanocomposites across various energies within error limits of 5 %. This study highlights the potential of Cr2O3/Bi2O3 NCs as a promising, sustainable alternative to conventional shielding materials, offering enhanced gamma radiation protection with reduced environmental impact.

Enhanced photodegradation of organic dyes using copper and zinc aluminate nanophotocatalysts

This study aims to enhance the photocatalytic efficiency of CuxZn1-xAl2O4 (x = 0.0, 0.2, 0.4, 0.6, and 0.8) nanophotocatalysts synthesized via a sol-gel self-combustion method. Rietveld analysis confirmed the formation of single-phase spinels with a face-centered cubic structure and Fd-3m space group symmetry, while electron density distribution analysis supported the ionic character of bonding within the material. Subsequent UV–visible spectroscopy revealed that the addition of Cu(II) reduced the band gap from 4.66 eV to 2.54 eV, facilitating enhanced light absorption. Consequently, the catalyst with x = 0.8 deteriorated 95 % of methyl orange (MO) and 93 % of rhodamine-B (RhB) in 120 min of visible light irradiation, following a pseudo-first-order kinetic model. The Cu0.8Zn0.2Al2O4 sample demonstrated significant reusability and stability, with degradation rates of 93–79 % for RhB and 95–81 % for MO after four cycles. Scavenging studies indicated that photoexcited holes (h), hydroxyl radicals (OH•), and superoxide radicals (O₂•⁻) were key factors in the degradation process. This study presents an improved approach for enhancing the photodegradation performance of the Cu0.8Zn0.2Al2O4 catalyst for pharmaceutical and wastewater treatment applications.

Green synthesis of silver, starch, and zinc oxide mediated nanoparticles with probiotics and plant extracts, their characterization and anti-bacterial activity

Nanotechnology has various applications in all branches of science, including engineering, medicine, pharmacy, and other related fields. Conventional techniques, such as the chemical reduction approach, which produces nanoparticles (NPs) using various hazardous chemicals, offer several health risks due to their toxicity and raise serious environmental concerns. In contrast, other techniques are expensive and need a lot of energy. More than 70 % of pathogenic bacterial strains have developed resistance to at least one class of antibiotics, leading to an increase in life-threatening bacterial infections that pose a significant health risk. However, the creation of NPs by biogenic synthesis is risk-free for the environment and clean enough for biological use. This study was aimed at synthesis of novel Moringa oleifera mediated starch capped silver-zinc NPs and green synthesis of ZnO nanoparticles from Aloe vera, papaya, and Lactobacillus plantarum. Antimicrobial activity of both NPs was tested against Gram-negative antibiotic-resistant bacteria Pseudomonas aeruginosa, Gram-positive bacteria Staphylococcus aureus (ATCC 6538), and two foodborne pathogens Listeria monocytogenes and Campylobacter jejuni. Ultraviolet–visible spectroscopy, Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy were used for characterization. Majority of the research studies stress the flexibility, repeatability, and desirable features of the metals, polymers, and plant components employed in the production of biomedical nanoparticles. Such an intuitive approach provides several advantages, particularly a reasonable total expense, compliance with healthcare and pharmaceutical implementations, and the ability to produce massive volumes for industrial use. The novelty of the presented work lies in the unusual combination of silver, starch, and zinc oxide nanoparticles using Moringa oleifera, which is an eco-friendly alternative to chemical-based methods. This research exhibits the formation of well-defined nanoparticles with strong antibacterial activity against a wide range of pathogens, giving us insights into their potential applications in various biomedical fields.

Antibacterial and Antioxidant Activities of Flavonoids, Phenolic and Flavonoid Glycosides from Gouania longispicata Leaves

The leaves of Gouania longispicata Engl. (GLE) have been traditionally used to treat more than forty ailments in Uganda, including stomachache, lung and skin cancers, syphilis, toothache, and allergies. In this study, pure compounds were isolated from the methanolic extract of GLE leaves and their structures elucidated using ultraviolet visible spectroscopy, liquid chromatography–tandem mass spectrometry, high performance liquid chromatography, and 1D and 2D NMR techniques. The antibacterial and antioxidant activities of the compounds were assessed using the broth dilution and DPPH assays, respectively. Two known flavonoid glycosides (kaempferol-3-O-α-rhamnopyranoside and rutin), a phenolic glycoside (4,6-dihydroxy-3-methylacetophenone-2-O-β-D-glucopyranoside), and flavonoids (kaempferol and quercetin) were characterized. This is the first time that the kaempferol derivative, the acetophenone as well as free forms of quercetin, kaempferol, and rutin, are being reported in GLE and the Gouania genus. The compounds exhibited antibacterial activity against Streptococcus pneumoniae and Escherichia coli with minimum inhibitory concentrations between 16 µg/mL and 125 µg/mL. The radical scavenging activities recorded half-minimum inhibitory concentrations (IC50) ranging from 18.6 ± 1.30 µg/mL to 28.1 ± 0.09 µg/mL. The IC50 of kaempferol and quercetin were not significantly different from that of ascorbic acid (p > 0.05), highlighting their potential as natural antioxidant agents. These results lend credence to the use of GLE leaves in herbal treatment of microbial infections and oxidative stress-mediated ailments.

Curcumin-loaded pickering emulsions based on soy protein isolate aggregates enhance diabetic wound healing

Wound healing in diabetic patients is more complex and prolonged in comparison to nondiabetic persons, and dealing with this problem has attracted considerable attention from researchers. According to its anti-inflammatory and anti-infective properties, Curcumin has a valued place in therapeutics, including wound healing. Still, its low stability and poor bioavailability are significant barriers to using its desirable properties. Hence, various biocompatible and biodegradable delivery systems have been developed to address this issue. In this study, Pickering emulsion (PE) prepared from soybean oil containing curcumin and modified SPI solution at 85 °C at pH 2.0 with 130 mM NaCl for different durations were used as a delivery system for curcumin. Changes in SPI properties were analyzed using fluorescence spectroscopy, Fourier transform infrared spectroscopy, and tensiometry methods. The prepared PEs were studied using microscopic techniques. Curcumin loading efficiency by PE was measured by UV–visible spectroscopy, and the impact of curcumin-loaded PE on wound healing was tested in diabetic rats. Spectroscopic studies and microscopy images revealed SPI amyloid-like aggregates suitable for stabilizing oil-in-water PEs. Tensiometry and creaming stability studies indicated that at least 6 h of heating (HSPI6) is necessary for optimal stability. Curcumin encapsulation efficiency was 95.7 ± 2.1 %. Curcumin-loaded PE-HSPI6 increased the healing rate of diabetic wounds in male Wistar rats by 1.46-fold. This study presents an approach for using biocompatible and biodegradable PEs to deliver hydrophobic compounds like curcumin for accelerating diabetic wound healing.

Operando Spectroelectrochemical Imaging of Concentration Fields and Tafel Kinetics in Microfluidic Electrochemical Devices.

With the development of microtechnologies for energy conversion and storage, mass transfer and micromolar concentration variations need to be measured at the microscale. These advances need to be accompanied by novel imaging techniques with the capability of achieving high spatial resolution while detecting very small signal variations (less than 0.1%). Thus, in this study, a new microscopy technique is proposed based on a combination of electrochemical impedance spectroscopy (EIS) and visible imaging spectroscopy to measure the concentration fields at the micromolar scale in operando microfluidic fuel cells (MFCs). This technique exploits EIS modulation and Fourier analysis to reduce the noise during concentration field imaging. A mass transfer model in the periodic regime is derived to validate the measurements and to estimate the Tafel kinetics and mass diffusivities during potassium permanganate reduction from only one potential measurement. The proposed imaging method and mathematical framework presented in this study can be used to study binary electrochemical reactions without gas production.

Development of quercetin loaded biosynthesized chitosan grafted iron oxide nanoformulation and their antioxidant, antibacterial, and anti-cancer properties

In this study, we report the development and characterization of a novel nanoformulation composed of quercetin-loaded biosynthesized chitosan-grafted iron oxide nanoparticles (CH-Fe3O4 NCs). The synthesis of chitosan-grafted iron oxide nanoparticles was achieved through a green synthesis approach, utilizing chitosan derived from crustacean shells and biosynthesized iron oxide nanoparticles. Quercetin, a natural flavonoid with known antibacterial, anti-cancer, and antioxidant properties, was loaded onto the nanoparticles through physical adsorption. The optical property, crystal structure, morphology, chemical composition and surface charge were thoroughly characterized using various analytical techniques including UV–visible spectroscopy, X-ray diffractometer, scanning and transmission electron microscopy, fourier-transform infrared spectroscopy and zeta potential analyzer. The antibacterial activity of the nanoformulation was evaluated against a panel of bacterial strains using standard microbiological assays, revealing promising inhibitory effects against both Gram-positive and Gram-negative bacteria. The antibacterial activity of CH-Fe3O4 NCs was evaluated against E. coli and S. aureus bacterial species. CH-Fe3O4 NCs have a greater ability to inhibit the E.coli than S. aureus. Furthermore, the CH-Fe3O4 NCs demonstrated dose-dependent cytotoxicity and caused apoptotic cell death in the H522 cell line. Additionally, the antioxidant properties of the nanoformulation were evaluated through scavenging assays, highlighting its ability to effectively neutralize free radicals. Overall, our results suggest that the quercetin-loaded biosynthesized chitosan-grafted iron oxide nanoformulation exhibits potent antibacterial, anti-cancer, and antioxidant properties, making it a promising candidate for further development as a multifunctional therapeutic agent.