Spectroscopic Techniques Research Articles

Fabrication of an electrochemical sensor based on Zinc Vanadate anchored with multi-walled carbon nanotubes modified glassy carbon electrode for the determination of Carbendazim

The detection of Carbendazim (CBZ) insecticides has prompted concerns regarding their potential impacts on both human health and the environment. To address this issue, a novel nanocomposite comprising Zinc Vanadate (ZVO) was prepared using a common hydrothermal technique and incorporated with multi-walled carbon nanotube (MWCNT) to form ZVO/MWCNT nanocomposite. Thus, a glassy carbon electrode (GCE) has been modified using this ZVO/MWCNT nanocomposite, which offering a simple and affordable platform for the electrochemcial detection of CBZ. The structure and composition of the nanomaterial were confirmed through various microscopic and spectroscopic techniques, while its electrochemical characteristics were investigated using electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and cyclic voltammetry (CV) techniques. The GCE/ZVO/MWCNT modified electrode exhibited a broad linear response ranging from 0.05 to 110μM, with a low detection limit of 0.005μM and high sensitivity (2.93 μA μM−1 cm−2), with recoveries ranging from 98% to 99.93%, respectively. Moreover, GCE/ZVO/MWCNT electrode demonstrated excellent stability, repeatability, and practical utility for CBZ detection. Based on electrochemical studies that indicate the formation of oxidized products consistent with a 2-electron transfer process. Therefore, this innovative GCE/ZVO/MWCNT modified electrode offers promising prospects for sensitive and selective CBZ determination, with potential applications in environmental monitoring and health protection.

Green synthesis of novel aryl sulfonyl-chromenones via one-pot, multi-component reaction using V2O5-FAp@MWCNT nanocomposite

A new, facile, environmentally friendly catalyst, V2O5-FAp@MWCNT, has been successfully synthesized. This catalytic material was characterized using various spectroscopic techniques, including FT-IR, P-XRD, SEM, EDS, and TEM. The catalytic activity of this nanomaterial was employed in the synthesis of aryl sulfonyl-chromenones under mild reaction circumstances. Further, the greener protocol offers numerous benefits, such as straightforwardness, inexpensive, use of a green solvent, eco-friendliness, an easy work-up process, less reaction times (under 30 min), waste minimization, straightforward purification, and excellent product yields (92–96%). Importantly, the catalyst material can be simply detached from the reaction via easy filtration and can be recycled multiple times without any loss in activity.

Impact of processing and storage on citrus fiber functionality: Insights from spectroscopic techniques

To deliver their functionality when used in applications, citrus fibers need to be rehydrated. Factors such as chemical composition, structural organization as well as chemical surface composition are known to influence this functionality. Processing and storage conditions can affect these parameters, making it challenging to maintain stable functionality. This study used Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to evaluate the effects of preparation and storage on citrus fibers. Samples dried at different scales and stored for 360 days under room and accelerated conditions were assessed for water holding capacity (WHC), water swelling capacity (WSC), and gel rigidity (G′). The results showed a decline in WHC, WSC, and G′ over time, confirming that aging negatively impacts moisture retention, particularly under higher water content or temperature. Drying scale had no effect on chemical composition or structure, but changes in the elemental surface composition of carbon and oxygen were noted. While prolonged storage altered the polysaccharides' chemical composition and structure, leading to functionality loss, XPS analysis revealed no changes in surface composition. Loss of functionality cannot be explained by chemical surface composition modifications.

Integrated in situ spectroscopic characterization of bi-functional nanoporous hybrid catalysts

Bi-functional catalysts possess various catalytic sites and can catalyze different types of reactions in a single-pot cascade manner. Herein, we report the synthesis and characterization of mono- and bifunctional silica-based mesoporous hybrid catalysts involving acid and base active sites. The ability for cooperative catalysis has been investigated using a multi-technique approach involving powder X-ray diffraction, FT-IR, and multinuclear MAS NMR spectroscopy, as well as thermogravimetric analysis. To elucidate the nature and strength of multifunctional catalytic sites, different types of probe molecules were employed and studied using spectroscopic techniques. The results show that the activity of the mesoporous surface-grafted acid and/or base sites is directly related to the intimacy criterion, the separation between the different types of catalytic sites. The presence or absence of mutual interactions between the different catalytic sites dictates the selectivity and yield of the reactions.

Detection of Organic Explosive Residues from Outdoor Detonations using Confocal Raman Microscopy

The detection of post-blast residues in the aftermath of an explosion involving organic explosives with spectroscopic techniques is challenging as, typically, no microscopically visible unreacted particles remain after the explosion. However, some low-order explosions may leave visible particles behind, as well as the presence of significant amounts of unreacted material. In this study, four authentic open-air detonations using two simulated improvised explosive devices (IEDs) containing a mixture of military explosives (TNT and RDX), and two IEDs containing smokeless powder were conducted. The various materials they contained, including plastic, wood, and metal, were swabbed and extracted with acetone to create post-blast liquid extracts. The extracts were then dried and examined using confocal Raman microscopy, alongside a 50 ppm reference mixture of smokeless powder constituents, which was created to evaluate the effects of Raman scattering within the full smokeless powder mixture. Smokeless powder constituents, such as ethyl centralite, diphenylamine, nitroglycerin, and dibutyl phthalate, were successfully identified by comparison to the reference mixture on most substrates, with the exception of the paint stick (wood) substrate. TNT/RDX was also able to be identified in the extracts, with RDX crystals being observed in some dried extracts after solvent evaporation. However, the detection of TNT/RDX in the second detonation was unsuccessful, possibly due to an explosive chain reaction that was highly efficient. No trends were seen in substrate affinity for TNT/RDX. The challenges and benefits with the developed methodology for the detection of organic explosive residues from a variety of substrates are discussed in detail.

In-silico Studies, Synthesis, and Antacid Activities of Magnesium (II) Complexes.

Nowadays, acidity is a severe problem worldwide caused by excessive gastric acid secretion by the stomach and proximal intestine. Antacids are drugs capable of buffering stomach acid. Therefore, in our research work, we have reported the in-silico studies, synthesis, characterization, and evaluation of antacid activities of magnesium (II) complexes via the acid-base neutralization process. In this research, some magnesium complexes were synthesized and their antacid behavior was compared with marketed products. Also, in-silico studies were performed on H+/K+ ATPase (Proton pump). All synthesized compounds were characterized by various spectroscopic techniques like UV-Vis, FT-IR, XRD, and DSC techniques. Spectroscopic analysis results showed that the semicarbazone ligand shows keto-enol isomerism and forms a coordinated stable complex with magnesium ions in the crystalline phase. The FT-IR results confirmed the presence of Mg-O stretching, N-H bending, and C=N stretching vibrations in Mg (II) complexes. The antacid activities of Mg (II) complexes were excellent as compared to the semicarbazone ligand and comparable with that of marketed antacid drugs like ENO, and Pantop-D. Insilco studies also confirmed that semicarbazone ligand and its Mg (II) complexes were both found to be fitted into the active sites of molecular targets, and Mg (II) complexes showed better binding affinities towards macromolecular as compared to semicarbazone ligand.

Selective diesterase-like activity of bioinspired FeIIINiII and FeIIIZnII complexes and their 3-aminopropyl silica composites: A homo- and heterogeneous catalytic study

In this study, the preparation and characterization of two new mixed-valence heterodinuclear complexes [FeIIINiII(BPPAMFF)(μ-OAc)2(H2O)]ClO4 (1) and [FeIIIZnII(BPPAMFF)(μ-OAc)2(H2O)]ClO4 (2) with the bioinspired ligand 2-[(N-benzyl-N-2-pyridylmethylamine)]-4-methyl-6-[N-(2-pyridylmethyl)aminomethyl)])-4-methyl-6-formylphenol (H2BPPAMFF) are reported. These compounds were immobilized in 3-aminopropyl silica (APS) to afford composites APS-1 and APS-2 successfully. The aldehyde-containing ligand provided a reactive functional group, which could serve as a cross-linking group to bind the complexes to the directly amino-modified SiO2 surface. The complexes’ chemical integrity on the APS inorganic platform were probed by spectroscopical techniques, such as FTIR, UV–Vis and EPR. Potentiometric and spectrophotometric titrations allowed the chemical species present in solution to be rationalized, and identified which of them were potentially active in the hydrolytic cleavage of phosphodiester 2,4-BDNPP. Kinetic studies showed that FeIIINiII species (1 and APS-1) presented higher catalytic efficiency (E = kcat/KM) than FeIIIZnII species (2 and APS-2). Catalytic mechanisms were proposed based on a series of kinetic experiments, in which all the catalysts tested behaved as selective phosphodiesterases. In addition, it was also demonstrated that the hydrolase activity of the immobilized catalytic centers, APS-1 and APS-2, was better than the homogeneous processes, where second coordination sphere effects may be involved in directing and stabilizing the transition state.

Synthesis, Antimicrobial and Antioxidant Activity of Some New Pyrazolines Containing Azo Linkages.

Pyrazolines and azo-pyrazolines are influential groups of heterocyclic compounds with two nitrogen atoms inside the five-membered ring. They play an important role in a wide range of biological processes, such as antifungal, antioxidant, antimalarial and other antimicrobial activities. The main objective of this study is to synthesize some new heterocyclic compounds with antioxidant and antimicrobial activity Methods: One-pot three components and traditional synthesis of new azo-pyrazoline compounds were achieved in this work. The preparation process has been started by diazotizing 4-(6-methylbenzothiazol-2-yl) benzamine and its coupling reaction with 4-hydroxy acetophenone producing azo-acetophenone, followed by benzylation with benzyl chloride to form the starting material, azo-benzyloxy acetophenone. A series of substituted benzaldehydes were reacted with the latter compound via one pot and classical methods, forming new chalcones containing azo linkages and benzyloxy moieties, which were then converted into new target azo-pyrazoline derivatives. The structures of the synthesized compounds were confirmed by spectroscopic techniques using FT-IR, 1H-NMR, 13C-NMR, and 13C- DEPT- 135 spectra. Finally, the synthesized compounds were screened for their antioxidant and antimicrobial activities against Staphylococcus aureus and Escherichia coli. Overall, the one-pot three-component synthesis of pyrazoline compounds generally provides advantages in terms of efficiency, simplicity, and time-consumption compared to classical synthesis methods. Hence, the study advocates the one-pot method because it eliminates the tedious process of making chalcones, which takes time, materials, and unnecessary effort. Therefore, this is the most convenient and effective approach to green chemistry.

Identification of imidazo[1,2-a]pyridines-pyrazole-pyran hybrids as potent glucose-6-phosphate dehydrogenase (G6PD) inhibitors: Synthesis, molecular docking, DFT studies and ADME prediction

In this study, we aimed to identify new anticancer agents by synthesizing a series of Imidazo[1,2-a]pyridines fused with pyrazole-pyran scaffolds 7a–g in good yields (75–85 %) under microwave irradiation. The synthesis was performed through a one-pot, three-component cyclocondensation reaction of 2-(p-substituted)imidazo[1,2-a]pyridine-3-carbaldehyde 4a-g, malononitrile 5, and 5-methyl-2,4-dihydro-3H-pyrazol-3-one 6 in the presence of triethylamine as a catalyst in acetonitrile. The characterization of all synthesized compounds was accomplished through various spectroscopic techniques. All the synthesized compounds were investigated for their anticancer potential in vitro, using an MTT-based assay against A549 lung cancer cell lines. Compounds 7b, 7e, and 7c demonstrated notable anti-proliferative activity against the A549 cell line, while compound 7e showed a significantly lower fluorescence generation (24-fold less) in the G6PD inhibition assay compared to the other compounds.

Molecular engineering of oxadiazole-based small organic-functional molecules as hole transporting materials for dopant-free perovskite solar cells

The present investigation concerns the synthesis and characterization of new hole-transporting materials (HTMs) for dopant free perovskite solar cells (PSCs). In this work, emphasis is placed on three new HTMs, specifically materials P-H, P-OMe, and P-CN, whose center-core is 2,2'-(4,8-bis(octyloxy)benzo[1,2-b:4,5-b']dithiophene (OBDT) and combined with two donor units of substituted triphenylamine as at both ends along with oxadiazole acceptor units in between donor and OBDT. The fabrication of perovskite solar cell devices using new HTMs and compared the power conversion performance with the standard spiro-OMeTAD HTM. Several spectroscopic techniques were utilized to characterize the properties of the new HTMs, such as FESEM analysis of thin-film morphologies, time-dependent photoluminescence (PL) spectra, and mobility measurements. The HTMs P-OMe established a compressed and steady protective layer on the perovskite layer. This layer contributed to the development of open-circuit voltage (VOC) and short-circuit current density (JSC), both of which are crucial for accomplishing high power conversion efficiency (PCE) in PSCs. The PSC device integrating the P-OMe HTM displayed a superior PCE of 21.14 % over an active area of 0.22 cm2. This activity was related to the standard device that utilized the standard Spiro-OMeTAD HTM, which accomplished a PCE of 17.46 %. The improved devices with the P-OMe HTM continued about 90 % of their initial PCE throughout maximum power point tracking (MPPT) for 90 days. Furthermore, these devices engaged in their activity over a further 2160 h under various temperature settings (25 °C and 35 °C), probably because of the hydrophobic property of the HTM.

Synthesis, Spectral Characterisation, DFT Calculations, Biological Evaluation and Molecular Docking Analysis of New Mannich Compounds Derived from Cyclopentanone

This research outlines the efficient one-pot calcium chloride-catalysed synthesis of three novel Mannich bases: M1, M2 and M3. M1 and M2 resulted from the condensing of benzaldehyde with m-nitroaniline and m-bromoaniline, respectively, in conjunction with cyclopentanone. However, M3 was obtained through the reaction of p-methoxybenzaldehyde, m-bromoaniline and cyclopentanone. The isolated compounds were thoroughly characterised using elemental analysis and various analytical and spectroscopic techniques, including the determination of their melting points, electrospray mass spectrometry (ESMS), Fourier transform infrared (FTIR), electronic spectroscopy (UV-Vis), and nuclear magnetic resonance (NMR) spectroscopy (1H- and 13C-NMR). Thermal stability (TGA and DTA analysis) of the three Mannich compounds was also examined. The newly synthesised Mannich bases exhibit remarkable potential as metal ion complexing agents and as fundamental building blocks for forming small organic molecules, particularly bioactive molecules and novel ligands for coordination chemistry. In addition to their structural significance, the biological efficacy of these compounds was assessed, revealing their excellent antimicrobial properties toward bacterial and fungal species. These activities suggest their potential use in combating microbial infections. Theoretical DFT simulations employing the B3LYP functional at the 6-311++G(d,p) level provided a thorough analysis of the stability of compounds, electrical properties, and geometry. Additionally, molecular docking studies of the Mannich compounds with two protein targets, 5IQ9 and 5VBU (both relevant for drug discovery) were performed. These studies revealed that the three Mannich compounds exhibit similar binding energies and effective interaction with both the 5IQ9 and 5VBU proteins, suggesting the potential of these Mannich compounds as dual inhibitors targeting both proteins.

Development of soft x-ray absorption spectroscopy technique with simultaneous measurement in electron- and fluorescence-yield modes from high vacuum to ambient pressure for observation of surface adsorbed species.

To understand the reactions of heterogeneous catalysts at the solid-gas interface under actual reaction conditions, it is important to develop a method to observe the surface-adsorbed species during the reaction, including the changes before and after the adsorption of light elements involved in the surface reaction. We developed a soft x-ray absorption spectroscopy (XAS) technique that allows simultaneous measurements in the electron- and fluorescence-yield modes in the pressure range of 10-4-1 × 105Pa. In the developed system, the reaction gas near the sample surface is separated from the beamline vacuum by a Si3N4 window and confined to a small area to suppress x-ray absorption by the gas. The electron-yield spectra were obtained by measuring the sample current while applying a bias potential to the Si3N4 window. XAS measurements were performed from high vacuum to ambient pressure by setting the bias potential to 600 and 39V below and above 100Pa, respectively. An anatase TiO2 nanoparticle-deposited film was prepared by spin coating, and soft XAS was performed to observe the photocatalytic oxidative decomposition reactions of isopropanol in the presence of water and oxygen. The obtained O K-edge spectra showed that it is possible to observe adsorbed oxygen on solid oxides even under ambient pressure conditions containing 0.1% of oxygen gas.

Hydrolysis of Poly(ester urethane): In-depth Mechanistic Pathway Determination through Thermal and Chemical Characterization

Many structure/property relationships of hydrolyzed poly(ester urethane) (PEU) – a thermoplastic polymer have been reported. Examples include changes in molecular weight vs. elongation at break and crosslink density vs. mechanical strength. However, the effect of molecular weight reduction on some physical, thermal, and chemical properties of hydrolyzed PEU have not been reported. Therefore, a large set of hydrolyzed PEU (Estane®5703) samples were obtained from two aging experiments: 1) accelerated aging conducted under various environments (air, nitrogen, moisture) and at 64°C and below for almost three years, and 2) natural aging conducted under ambient conditions for more than four decades. The hydrolyzed samples were characterized via multi-detection gel permeation chromatography (GPC), thermogravimetric analysis (TGA), modulated differential scanning colorimetry (mDSC), UV-vis spectroscopy, nuclear magnetic resonance (NMR), and Fourier-transform infrared (FTIR) spectroscopy techniques. Hydrolysis of ester linkages in the soft-segments decreases both the molecular weight of the polymer and the melting point of Estane from ∼55°C to 39°C. Aging above this melting temperature (Tm), increased mobility of polymer chains and water diffusivity alter the PEU degradation pathway from those expected at aging temperatures below Tm and have significant bearing on the critical molecular weight (MC) at which the physical, chemical, thermal, and mechanical properties of Estane change abruptly. While a MC value of 20 kDa is found for PEU hydrolysis at mild temperatures (e.g., below 39°C), the MC increases with increasing aging temperature. To complement the existing structure/property relationships reported in the literature, more correlations are obtained, which include the effect of Mw on polydispersity, intrinsic viscosity (Mark-Houwink equation), UV extinction coefficient, and dn/dc (GPC analysis) values. Furthermore, we seek to augment previously reported aging models for PEU by developing a practical model with which the extent of degradation and material performance can be predicted based on aging under different temperature ranges both above and below the melting point of the hard-segments.

A Novel Cortex Phellodendri Chinensis-Based Carbon Dots Platform for Remarkable Analgesia for Clinical Pain Management.

In this study, we explored the eco-friendly synthesis of photoluminescent CCDs employing a direct one-step pyrolysis process, utilizing natural Cortex Phellodendri Chinensis as the precursor material and studied their analgesic effect in mice. The synthesized carbon dots underwent comprehensive characterization through a range of spectroscopic and microscopic techniques. These included UV-Vis, FTIR, fluorescence spectroscopy and HR-TEM, DLS instruments. HR-TEM results exhibited the presence of homogenous spherical-shaped C-dots of about 3.3nm without aggregates. Furthermore, the prepared CCDs were studied for their in vivo analgesic effect in mice by performing tail-immersion, hot plate and acetic acid writhing tests. Also, an MTT assay was performed to assess the in vitro cytotoxicity of CCDs against L929 cells. In vitro cytotoxicity studies revealed that L929 cells exhibited higher cell viability when treated with prepared CCDs. The cellular uptake studies revealed the phase contrast images of MG-63 cells at wavelength 488nm clearly depicted the aggregation of green, fluorescent CCDs within the cells while leaving nuclei unobscured. In addition, to the best of our understanding, the results presented in this paper showed that CCDs exhibited an important analgesic effect and enhanced anti-nociceptive activity, which may be due to stimulation of the opioidergic system. Consequently, CCDs appear to be a viable analgesic alternative for traditional analgesic candidates in pain management.

Dendritic copper nanostructures for ultrasensitive detection of rhodamine 6G and Congo red

Surface-Enhanced Raman Scattering (SERS) is a fast-responding and non-destructive ultra-sensitive detection technique that can replace traditional chromatographic and spectroscopic analysis techniques. In this experiment, dendritic copper nanostructures were prepared by the solid-state ionics method and the vacuum hot evaporation process with an applied current of I=9μA. Using them as a SERS substrate, Raman detection was performed on the dye molecules Rhodamine 6G (R6G) and Congo Red (CR) to determine SERS enhancement performance. It is found that the growth of the prepared copper nanostructures has a top-end dominant phenomenon. The fractal dimension of the copper nanostructure was calculated using fractal theory, and it was revealed to be 1.560. Scanning electron microscopy (SEM) results showed that a large number of 60-80 nm regularly arranged copper nanoparticles were attached to the surface of the dendritic copper nanostructure. This is beneficial to increase the surface roughness of the substrate and improve the detection level of dye molecules. Subsequently, copper nanostructures can sensitively detect R6G and CR solutions as low as 1×10-13 mol/L and 1×10-7 mol/L, reaching single-molecule levels. The Raman mapping experiment showed that the mean relative standard deviation (RSD) values of R6G and CR were 12.3% and 12.9%, indicating high uniformity and reproducibility of the structure. This structure effectively achieves the fusion of uniformity, repeatability, and sensitivity, and shows broad application prospects in food detection.

Efficient Adsorptive Removal of Levofloxacin Using Sulfonated Graphene Oxide: Adsorption Behavior, Kinetics, and Thermodynamics

Water pollution by antibiotic residues poses a potential threat to environmental and human health. Graphene-based materials are highly stable, recyclable and effective adsorbents for efficiently removing antibiotics from polluted water. In this study, the adsorption behavior of levofloxacin onto sulfonated graphene oxide (SGO) was investigated by varying the contact period, solution pH, adsorbent quantity, levofloxacin concentration, inorganic ions, and solution temperature. Spectroscopic and microscopic techniques were employed to confirm the adsorptive interaction between levofloxacin and SGO. The adsorption process was most accurately characterized by the pseudo-second-order kinetic model and the Langmuir isotherm model, as indicated by their high correlation coefficients (R2) and low root-mean-square error (RMSE) values. The maximal quantity of levofloxacin that can be adsorbed onto SGO was determined to be 1250 μmol/g at pH 4 and 25 °C using the Langmuir model. Thermodynamic studies reveal that the process of levofloxacin adsorption onto SGO is endothermic and spontaneous in nature. Taking into consideration the results of adsorption, desorption and regeneration studies, it is proposed that SGO can be applied as an economic viable agent for the adsorptive removal of levofloxacin from the aqueous environment.

Analysis of Eleonore Koch's artwork and powdered pigments from MAC-USP and Pinacoteca of São Paulo collections

Eleonore Koch is a German artist known for her paintings featuring arrangements of colors and ordinary objects. She spent a significant part of her life in Brazil, where she had the opportunity to interact with and learn from Alfredo Volpi, a colorist artist who introduced her to the tempera technique and the use of natural and mineral pigments, replacing oil-based industrial ones. A collection of powdered pigments she used during her lifetime was studied by spectroscopic analysis, forming an initial basis of knowledgement about Koch's pigments. In this paper, one painting from the Museum of Contemporary Art of the University of Sao Paulo (MAC-USP) collection was analyzed by spectroscopic (ED-XRF, Raman and FTIR) and imaging techniques. The painting palette was compared with some powdered pigments from the artist's collection. The pigments identified in the artwork are Chrome Oxide Green, Titanium White, Phthalocyanine Blue, Ivory or Bone Black and a yellowish/brown pigment rich in hematite. The findings indicate that most of the pigments found in Koch's artwork were also part of her personal collection.

Alginate‑carbon dot nanocomposite: A green approach towards designing turn-on aptasenor for Candida albicans fungus

Candida albicans fungus, an opportunistic microorganism that becomes a pathogen in its host, can often cause superficial and severe infections in human body. In this work, a turn-on fluorescent aptasenor based on Alginate‑carbon dot nanocomposite has been designed through a green approach. Carbon dots (CDs) with average size of 4 ± 1 nm were synthesized hydrothermally using Philodendron bipinnatifidum plant extract as precursor. Then, mixture of carbon dot and alginate was cross-linked by Ca2+ ions to make Alginate-CD nanocomposite with negligible effect on fluorescence intensity of CDs (λex = 360 nm, λem = 400 nm). The fluorescence quantum yield and lifetime were found as 14.1 % and 3.15 ns, respectively. The nanocomposite was characterize using different spectroscopic (Photoluminescence, UV–visible, XPS, FT-IR) and microscopic (TEM and SEM) analytical techniques. An aptamer was used to selectively target (1 → 3)-β-D-glucan on the surface of the Candida albicans cell wall. It was found that the fluorescence energy resonance transfer between nanocomposite and aptamer quenches the fluorescence intensity of nanocomposite, making it suitable for designing turn-on fluorescent probe. It was found that the fluorescence could be recovered in the presence of Candida albicans fungus (in <30 min), owing to higher affinity between aptamer and (1 → 3)-β-D-glucan on the surface of Candida albicans fungus, where there were two linear ranges: low concentration of 50–200 cells/mL and high concentration of 1000–6000 cells/mL (R2 ≥ 0.989 for both linear ranges), with limit of detection of 40 cells/mL. The selectivity of the designed probe was examined against a mixture of microbial agents (Staphylococcus aureus and Escherichia coli) and Curdlan polysaccharide (1→3)-b-D-Glucan (L). The designed biosensor showed an excellent ability to directly detect Candida albicans fungus via a simple and fast (<30 min) approach. The results of this experimental study show that Alginate-CD-aptamer nanocomposite is a bright prospect in clinical applications and a suitable alternative to traditional methods of Candida albicans diagnosis.

Novel quinoline-based chemosensor as specific fluorescence sensing of copper ions in cancer cells and for organelle-specific imaging application

This work reports a simple synthesis of a quinoline-based organic molecule, (E)-N′-((6-methoxy-2-oxo-1,2-dihydroquinolin-3-yl)methylene) picolinohydrazide (PHMQ), and its ability to distinguish Cu2+ ion. Through the use of spectroscopic and photometric titration techniques, PHMQ’s selectivity toward various cations and anions was examined. In just two minutes, PHMQ showed fast detection of Cu2+ ions, and clear spectral fluctuations proposed persistent PHMQ-Cu2+ complex formation. The calculated emission quenching constant (1.46 × 105 L/mol) and binding constant (1.25 × 104 L/mol) values suggested that strong emission quenching occurs between the PHMQ and Cu2+ ions. A linear reduction in fluorescence response was noted for Cu2+ ions concentrations between 2–26 μM, with a detection limit of 43.4 nM. Job’s plot, ESI-mass, NMR titration experiments, and density functional theory (DFT) simulations established a 1:1 stoichiometry for the PHMQ-Cu2+ complex. Additionally, PHMQ was efficaciously utilized to quantify Cu2+ ions in drinking and tap water samples and HeLa cells, illustrating durable cellular penetrability and a fluorescence ’Turn-Off’ response to Cu2+ ions. This sensor also established usefulness in mitochondrial-targeted imaging. For the detection of Cu2+ ions in biological and environmental environments, PHMQ is a promising detector due to its high sensitivity, selectivity, and quick response.

Novel 3D plate-like g-C3N4/BiOCl heterojunction as a highly efficient photocatalyst for the degradation of carbofuran in wastewater under visible light irradiation

The g-C3N4/BiOCl (gCN-BCl) heterojunction photocatalyst was synthesized using a low-temperature precipitation method for effective photocatalytic degradation of carbofuran (CBF). All gCN-BCl composites demonstrate greater efficacy in removing CBF compared to its individual constituents. The synergistic effect of incorporating the 0D structured BiOCl onto the 2D structured g-C3N4 was comprehensively examined using various microscopic, X-ray, and spectroscopic analytical techniques. Additionally, optical and photoelectrochemical analyses were conducted. The findings validated that the interaction between the two semiconductors at the heterointerfaces enhanced remarkable physical and structural stability, promoted high charge separation and transfer properties, and improved photocatalytic degradation. Under optimal conditions, 5-gCN-BCl (0.25 g/L) achieved a CBF (5 mg/L) removal efficiency of 95.7 % under visible light irradiation of 120 min, achieving 3.1- and 5.9-times higher degradation rate than the pure BiOCl and g-C3N4, respectively. The radical trapping experiments indicated that the h+ and •O2− were the primary reactive species involved in the CBF degradation. Furthermore, the potential toxicity of CBF and its intermediates was assessed, revealing that the photocatalytic degradation process significantly lowered the ecotoxicity of pesticide wastewater. The potency of 5-gCN-BCl was also evaluated in tap water and real wastewater samples, with CBF degradation efficiencies of 85.8 %, 47.6 %, and 38.7 % in tap water, municipal, and pesticide industry wastewater, respectively. Additionally, artificial neural network (ANN) modeling was employed to predict and optimize the photocatalytic degradation process, providing further insights into the system’s performance. The outcomes of this work offer valuable insights into the development of heterojunction photocatalysts with superior stability and efficacy for eliminating pesticides from water bodies.