Nanoscale potassium sensing based on valinomycin-anchored fluorescent gold nanoclusters.

Gold nanoclusters are a smart platform for sensing potassium ions (K+). They have been synthesized using bovine serum albumin (BSA) and valinomycin (Val) to protect and cap the nanoclusters. The nanoclusters (Val-AuNCs) produced have a red emission at 616 nm under excitation with 470 nm. In the presence of K+, the valinomycin polar groups switch to the molecule's interior by complexing with K+, forming a bracelet structure, and being surrounded by the hydrophobic exterior conformation. This structure allows a proposed fluorometric method for detecting K+ by switching between the Val-AuNCs' hydrophilicity and hydrophobicity, which induces the aggregation of gold nanoclusters. As a result, significant quenching is seen in fluorescence after adding K+. The quenching in fluorescence in the presence of K+ is attributed to the aggregation mechanism. This sensing technique provides a highly precise and selective sensing method for K+ in the range 0.78 to 8 µM with LOD equal to 233 nM. The selectivity of Val-AuNCs toward K+ ions was investigated compared to other ions. Furthermore, the Val-AuNCs have novel possibilities as favorable sensor candidates for various imaging applications. Our detection technique was validated by determining K+ ions in postmortem vitreous humor samples, which yielded promising results.

Design a Friendly Nanoscale Chemical Sensor Based on Gold Nanoclusters for Detecting Thiocyanate Ions in Food Industry Applications.

The surfactant cetyltrimethylammonium bromide (CTAB) induces the aggregation of gold nanoclusters (GNCs), leading to the development of a proposed fluorometric technique for detecting thiocyanate (SCN-) ions based on an anti-aggregation mechanism. This approach is straightforward to execute, highly sensitive, and selective. A significant quenching effect occurs in fluorescence upon using the aggregation agent CTAB in GNCs synthesis, resulting in a transition from intense red fluorescence to dim red. The decrease in fluorescence intensity of GNCs in the presence of CTAB is caused by the mechanism of fluorescence quenching mediated by aggregation. As the levels of SCN- rise, the fluorescence of CTAB-GNCs increases; this may be detected using spectrofluorometry or by visually inspecting under UV irradiation. The recovery of red fluorescence of CTAB-GNCs in the presence of SCN- enables the precise and discerning identification of SCN- within the concentration range of 2.86-140 nM. The minimum detectable concentration of the SCN- ions was 1 nM. The selectivity of CTAB-GNCs towards SCN- ions was investigated compared to other ions, and it was demonstrated that CTAB-GNCs exhibit exceptional selectivity. Furthermore, we believe that CTAB-GNCs have novel possibilities as favorable sensor candidates for various industrial applications. Our detection technique was validated by analyzing SCN- ions in milk samples, which yielded promising results.

Dual-emission ciprofloxacin-gold nanoclusters enable ratiometric sensing of Cu2+, Al3+, and Hg2.

An innovative triple optical sensor is presented that utilizes gold nanoclusters (GNCs) stabilized with ciprofloxacin (CIP) and bovine serum albumin (BSA). The sensor is designed to identify three critical metal ions, namely Cu2+, Al3+, and Hg2+. Under 360 nm excitation, the synthesized CIP-BSA-GNCs demonstrate dual fluorescence emission with peaks at 448 nm (blue) and 612 nm (red). The red emission is associated with the interior of the CIP-BSA-GNCs, whereas the blue emission results from the surface-bound CIP molecules. The sensitive and selective fluorescent nanosensor CIP-BSA-GNCs were employed to detect Cu2+, Al3+, and Hg2+ ions. Cu2+ effectively quenched the fluorescence intensity of the CIP-BSA-GNCs at both peaks via the internal charge transfer mechanism (ICT). Cu2+ could be detected within the concentration range 1.13 × 10-3 to 0.05 µM, with a detection limit of 0.34 nM. Al3+ increased the intensity of CIP fluorescence at 448 nm via the chelation-induced fluorescence enhancement mechanism. The fluorescence intensity of the core CIP-BSA-GNCs at 612 nm was utilized as a reference signal. Thus, the ratiometric detection of Al3+ succeeded with a limit of detection of 0.21 nM within the dynamic range 0.69 × 10-3 to 0.07 µM. Hg2+ effectively quenched the fluorescence intensity of the CIP-BSA-GNCs at 612 nm via the metallophilic interaction mechanism. The fluorescence intensity of CIP molecules at 448 nm was utilized as a reference signal. This allowed for the ratiometric detection of Hg2+ with a detection limit of 0.7 nM within the concentration range 2.3 × 10-3 to 0.1 µM.

Terminal Residues and Risk Assessment of Spiromesifen and Spirodiclofen in Tomato Fruits.

Insecticides are important to increase crop yields, but their overuse has damaged the environment and endangered human health. In this study, residues of spiromesifen and spirodiclofen were determined in tomato fruit using a simple and efficient analytical procedure based on acetonitrile extraction, extract dilution, and UPLC-MS/MS. The linearity range was 1-100 µg/kg and 0.5-100 µg/kg, and the correlation coefficient (R2) and residuals were ≥0.9991 and ≤16.4%, respectively. The limit of determination (LOD) was 0.26 and 0.08 µg/kg, while the limit of quantification (LOQ) was verified at 5 µg/kg. The relative standard deviation of spiked replicates at 5 µg/kg analyzed in one day (RSDr, n = 6) was ≤8.35%, and within three different days (RSDR, n = 18) it was ≤15.85%, with recoveries exceeding 91.34%. The method recovery test showed a satisfactory value of 89.23-97.22% with an RSD of less than 12.88%. The matrix effect was determined after a 4-fold dilution of the raw extract and was -9.8% and -7.2%, respectively. The validated method was used to study the dissipation behavior of the tested analytes in tomato fruit under field conditions. First-order kinetics best described the dissipation rates. The calculated half-lives were 1.49-1.83 and 1.91-2.38 days for spiromesifen and spirodiclofen, respectively, after application of the authorized and doubled authorized doses, indicating that spiromesifen dissipated more rapidly than spirodiclofen. The final residue concentrations of spiromesifen and spirodiclofen were 0.307-0.751 mg/kg and 0.101-0.398 mg/kg, respectively, after two or three applications, and were below the European Union (EU) maximum residue limits. The chronic risk assessment indicates that both insecticides are safe for adult consumers.

A New, Extremely Sensitive, Turn-Off Optical Sensor Utilizing Schiff Base for Fast Detection of Cu(II).

Throughout this research, a unique optical sensor for detecting one of the most dangerous heavy metal ions, Cu(II), was designed and developed. The (4-mercaptophenyl) iminomethylphenyl naphthalenyl carbamate (MNC) sensor probe was effectively prepared. The Schiff base of the sensor shows a "turn-off" state with excellent sensitivity to Cu(II) ions. This innovative fluorescent chemosensor possesses distinctive optical features with a substantial Stocks shift (about 114 nm). In addition, MNC has remarkable selectivity for Cu(II) relative to other cations. Density functional theory (DFT) and the time-dependent DFT (TDDFT) theoretical calculations were performed to examine Cu(II) chelation structures and associated electronic properties in solution, and the results indicate that the luminescence quenching in this complex is due to ICT. Chelation-quenched fluorescence is responsible for the internal charge transfer (ICT)-based selectivity of the MNC sensing molecule for Cu(II) ions. In a 1:9 (v/v) DMSO-HEPES buffer (20 mM, pH = 7.4) solution, Fluorescence and UV-Vis absorption of the MNC probe and Cu(II) ions were investigated. By utilizing a solution containing several metal ions, the interference of other metal ions was studied. This MNC molecule has outstanding selectivity and sensitivity, as well as a low LOD (1.45 nM). Consequently, these distinctive properties enable it to find the copper metal ions across an actual narrow dynamic range (0-1.2 M Cu(II)). The reversibility of the sensor was obtained by employing an EDTA as a powerful chelating agent.

Superhydrophobic and Corrosion Behaviour of PVDF-CeO2 Composite Coatings.

Composite coatings of polyvinylidene fluoride (PVDF)/CeO2 were developed by using the spray approach to explore the wetting and corrosion behaviour of coated materials for applications related to industry. PVDF was combined with different quantities of CeO2 nanoparticles followed by spraying onto glass, aluminium, and steel substrates. The sessile droplet method and microscopy studies were used to assess the wetting behaviour and morphology of the coated surfaces, respectively. The corrosion resistance of uncoated substrates coated with PVDF only was compared with those coated with PVDF/CeO2 nanoparticles through Tafel polarization techniques. In psi, the force of adhesion was measured between the coating layer and the substrates. The PVDF/CeO2-coated steel had a significantly greater water contact angle and lower contact angle hysteresis than coated aluminium and glass substrates, reaching 157 ± 2° and 8 ± 1°, respectively. The corrosion protection efficiency of the superhydrophobic PVDF/CeO2 coatings was considerably higher for steel and aluminium when compared with PVDF coatings. The PVDF/CeO2 coated substrates had modest adhesion between the coating layer and the substrates, but it was still acceptable. Furthermore, the PVDF/CeO2 coatings outperformed PVDF alone in terms of mechanical properties.

A Reversible Optical Sensor Film for Mercury Ions Discrimination Based on Isoxazolidine Derivative and Exhibiting pH Sensing.

We developed a new optical sensor for tracing Hg(II) ions. The detection affinity examines within a concentration range of 0-4.0 µM Hg(II). The sensor film is based on Methyl 2-hydroxy-3-(((2S,2'R,3a'S,5R)-2-isopropyl-5,5'-dimethyl-4'-oxotetrahydro-2'H-spiro[cy-clohexane-1,6'-im-idazo[1,5-b]isoxazol]-2'-yl)methyl)-5-methylbenzoate (IXZD). The novel synthesized compound could be utilized as an optical turn-on chemosensor for pH. The emission intensity is highly enhanced for the deprotonated form concerning the protonated form. IXZD probe has a characteristic fluorescence peak at 481 nm under excitation of 351 nm with large Stocks shift of approximately 130 nm. In addition, the binding process of IXZD:Hg(II) presents a 1:1 molar ratio which is proved by the large quench of the 481 nm emission peak of IXZD and the growth of a new emission peak at 399 nm (blue shift). The binding configurations with one Hg(II) cation and its electronic characteristics were investigated by applying the Density Functional Theory (DFT) and the time-dependent DFT (TDDFT) calculations. Density functional theory (DFT) and the time-dependent DFT (TDDFT) theoretical results were provided to examine Hg(II)-IXZD structures and their electronic properties in solution. The developed chemical sensor was offered based on the intramolecular charge transfer (ICT) mechanism. The sensor film has a significantly low limit of detection (LOD) for Hg(II) of 0.025 µM in pH 7.4, with a relative standard deviation RSDr (1%, n = 3). Lastly, the IXZD shows effective binding affinity to mercury ions, and the binding constant Kb was estimated to be 5.80 × 105 M-1. Hence, this developed optical sensor film has a significant efficiency for tracing mercury ions based on IXZD molecule-doped sensor film.

New 1,2,3-Triazole-Coumarin-Glycoside Hybrids and Their 1,2,4-Triazolyl Thioglycoside Analogs Targeting Mitochondria Apoptotic Pathway: Synthesis, Anticancer Activity and Docking Simulation.

Toxicity and resistance to newly synthesized anticancer drugs represent a challenging phenomenon of intensified concern arising from variation in drug targets and consequently the prevalence of the latter concern requires further research. The current research reports the design, synthesis, and anticancer activity of new 1,2,3-triazole-coumarin-glycosyl hybrids and their 1,2,4-triazole thioglycosides as well as acyclic analogs. The cytotoxic activity of the synthesized products was studied against a panel of human cancer cell lines. Compounds 8, 10, 16 and 21 resulted in higher activities against different human cancer cells. The impact of the hybrid derivative 10 upon different apoptotic protein markers, including cytochrome c, Bcl-2, Bax, and caspase-7 along with its effect on the cell cycle was investigated. It revealed a mitochondria-apoptotic effect on MCF-7 cells and had the ability to upregulate pro-apoptotic Bax protein and downregulate anti-apoptotic Bcl-2 protein and thus implies the apoptotic fate of the cells. Furthermore, the inhibitory activities against EGFR, VEGFR-2 and CDK-2/cyclin A2 kinases for 8, 10 and 21 were studied to detect the mechanism of their high potency. The coumarin-triazole-glycosyl hybrids 8 and 10 illustrated excellent broad inhibitory activity (IC50= 0.22 ± 0.01, 0.93 ± 0.42 and 0.24 ± 0.20 µM, respectively, for compound 8), (IC50 = 0.12 ± 0.50, 0.79 ± 0.14 and 0.15± 0. 60 µM, respectively, for compound 10), in comparison with the reference drugs, erlotinib, sorafenib and roscovitine (IC50 = 0.18 ± 0.05, 1.58 ± 0.11 and 0.46 ± 0.30 µM, respectively). In addition, the docking study was simulated to afford better rationalization and put insight into the binding affinity between the promising derivatives and their targeted enzymes and that might be used as an optimum lead for further modification in the anticancer field.

Microwave-Assisted Rapid Synthesis of Luminescent Tryptophan-Stabilized Silver Nanoclusters for Ultra-Sensitive Detection of Fe(III), and Their Application in a Test Strip.

A new preparation method for extreme fluorescent green emission tryptophan-stabilized silver nanoclusters (Tryp-AgNCs) is presented in this scientific research. The produced silver nanoclusters are dependent on tryptophan amino acid which contributes to normal growth in infants and the sublimation and recovery of human protein, muscles, and enzymes. Herein, we have introduced a green method by using microwave-assisted rapid synthesis. The subsequent silver nanoclusters (AgNCs) have excitation/emission peaks at 408/498 nm and display a considerable selectivity to Fe(III) ions. The tryptophan amino acid molecule was used in the synthesis process as a reducing and stabilizing agent. The Tryp-AgNCs' properties were investigated in terms of morphology, dispersity, and modification of the synthesized particles using different advanced instruments. The luminescent nanoclusters traced the Fe(III) ions by the luminescence-quenching mechanism of the Tryp-AgNCs luminescence. Therefore, the extreme selectivity of the prepared nanoclusters was exhibited to the Fe(III) ions, permitting the sensitive tracing of ferric ions in the lab and in the real environmental samples. The limit of detection for Fe(III) ions based on Tryp-AgNCs was calculated to be 16.99 nM. The Tryp-AgNCs can be efficiently applied to a paper test strip method. The synthesized nanoclusters were used efficiently to detect the Fe(III) ions in the environmental samples. Moreover, we examined the reactivity of Tryp-AgNCs on various human tumor cell lines. The results show that the Tryp-AgNCs exhibited their activity versus the cancer cells in a dose-dependent routine for the perceived performance versus the greatest-used cancer cell lines.

High-Quality Bioethanol and Vinegar Production from Saudi Arabia Dates: Characterization and Evaluation of Their Value and Antioxidant Efficiency.

Dates are very rich in various nutritious compounds, especially reducing sugars. Sugars ensure both anaerobic and aerobic fermentation, carried out respectively for the production of bioethanol and vinegar. Currently, the world production of dates is constantly increasing owing to the significant improvement in production conditions following the continuous scientific and technological development of this field. The Kingdom of Saudi Arabia is one of the most important world producers of dates, occupying the second place by producing 17% of the total world production. This is why it has become a national priority to find new ways to exploit and further valorize dates and palm waste in the development of new and sustainable products. The present study was designed to explore the possible study of a variety of date palm by-products in the production of bioethanol and vinegar via Saccharomyces cerevisiae. Different parameters of bioethanol and vinegar production, including pH, time, fermentation temperature, and yeast concentration, were studied and optimized. Chemical, physicochemical, purity behavior, and antioxidant performance were carried out via NMR, FTIR, and antioxidant activity essays (TPC, DPPH, FRAP, and ß-carotene bleaching test) with the aim to evaluate the potential of the bioethanol and vinegar samples extracted from date palm by-products. Khalas date vinegar revealed significantly more phenolic content (5.81 mg GAE/mL) (p < 0.05) than the different kinds of vinegar tested (Deglet Nour and Black dates; 2.3 and 1.67 mg GAE/mL, respectively) and the commercial vinegar (1.12 mg GAE/mL). The Khalas date vinegar generally showed a higher carotenoid value and better antioxidant activity than the other vinegars extracted from other date varieties and commercially available vinegar. The results confirmed the high quality of the bioethanol and vinegar products, and the efficiency of the developed production processes.

An Eco-Friendly Synthetic Approach for Copper Nanoclusters and Their Potential in Lead Ions Sensing and Biological Applications.

A new preparation route for high-luminescent blue-emission pepsin copper nanoclusters (Pep-CuNCs) is introduced in this work. The synthesized nanoclusters are based on a pepsin molecule, which is a stomach enzyme that works to digest proteins that exist in undigested food. Here, we have developed an eco-friendly technique through microwave-assisted fast synthesis. The resulting copper nanoclusters (CuNCs) exhibit significant selectivity towards Pb(II) ions. The pepsin molecule was utilized as a stabilizer and reducing agent in the production procedure of Pep-CuNCs. The characteristics of the resulting Pep-CuNCs were studied in terms of size, surface modification, and composition using various sophisticated techniques. The CuNCs responded to Pb(II) ions through the fluorescence quenching mechanism of the CuNCs' fluorescence. Thus, great selectivity of Pep-CuNCs towards Pb(II) ions was observed, allowing sensitive determination of this metal ion at lab-scale and in the environment. The CuNCs have detection limits for Pb(II) in very tenuous concentration at a nanomalar scale (11.54 nM). The resulting Pep-CuNCs were utilized significantly to detect Pb(II) ions in environmental samples. Additionally, the activity of Pep-CuNCs on different human tumor cell lines was investigated. The data for the observed behavior indicate that the Pep-CuNCs displayed their activity against cancer cells in a dose dependent manner against most utilized cancer cell lines.

Novel 1,2,3-Triazole-Coumarin Hybrid Glycosides and Their Tetrazolyl Analogues: Design, Anticancer Evaluation and Molecular Docking Targeting EGFR, VEGFR-2 and CDK-2.

This study represents the design and synthesis of a new set of triazole-coumarin-glycosyl hybrids and their tetrazole hybrid analogues possessing various sugar moieties and modified analogues. All the newly synthesized derivatives were screened for their cytotoxic activities against a panel of human cancer cell lines. The coumarin derivatives 10, 13 and 15 derivatives revealed potent cytotoxic activities against Paca-2, Mel-501, PC-3 and A-375 cancer cell lines. These promising analogues were further examined for their inhibitory assessment against EGFR, VEGFR-2 and CDK-2/cyclin A2 kinases. The coumarin-tetrazole 10 displayed broad superior inhibitory activity against all screened enzymes compared with the reference drugs, erlotinib, sorafenib and roscovitine, respectively. The impact of coumarin-tetrazole 10 upon cell cycle and apoptosis induction was determined to detect its mechanism of action. Additionally, it upregulated the levels of casp-3, casp-7 and cytochrome-c proteins and downregulated the PD-1 level. Finally, molecular docking study was simulated to afford better rationalization and gain insight into the binding affinity between the promising derivatives and their targeted enzymes, which could be used as an optimum lead for further modification in the anticancer field.

Green synthesis of pregabalin-stabilized gold nanoclusters and their applications in sensing and drug release.

This is the first report on the simple preparation of gold nanoclusters stabilized with pregabalin (PREG) as a capping and reducing agent. PREG is an active pharmaceutical ingredient of the commercially available drug "Lyrica" used to treat different diseases like epilepsy and anxiety. PREG has never been used before in the synthesis of any nanoparticles or nanoclusters. The prepared gold nanoclusters (PREG-stabilized gold nanoclusters [PREG-AuNCs]) have blue fluorescence with excitation/emission at 365/425 nm, respectively. The reaction conditions were optimized for the synthesis of the as-prepared AuNCs. Different tools were used for the characterization of the synthesized nanoclusters in terms of size and surface properties. The PREG-AuNCs were exploited as a sensitive and selective fluorescent nanosensor for Cu2+ detection. The quenching of AuNC fluorescence intensity in the presence of Cu2+ is due to the aggregation-induced fluorescence quenching mechanism. The detection limit of Cu2+ ions was found to be 1.11 × 10-7 M. The selectivity of the PREG-AuNCs was studied and proved to be excellent. The drug entrapment efficacy and in vitro drug diffusion studies along with drug release kinetics helped to understand more about the pharmaceutical approaches of PREG-AuNCs. Moreover, we think that PREG-AuNCs open new opportunities as a promising candidate material for drug delivery systems and medical applications.

Performance of Sprayed PVDF-Al2O3 Composite Coating for Industrial and Civil Applications.

Because of their great water repellency, Superhydrophobic coatings have a major impact on a variety of industrial applications. The current study's key originality is the development of low-cost, stable, superhydrophobic, and corrosion-resistant composite coatings. In the present work, polyvinylidene fluoride (PVDF)/Al2O3 composite coatings were produced using the spray technique to investigate the wettability and corrosion behavior of the coated materials for industrial and civil applications. PVDF was mixed with various concentrations of Al2O3 nanoparticles, and the mixture was sprayed onto steel, aluminum, and glass substrates. The wettability and morphology of the coated surfaces were investigated using the sessile droplet method and scanning electron microscopy, respectively. The corrosion resistance of bare substrates was compared to that of those coated with PVDF alone and those coated with PVDF/Al2O3 nanoparticles using Tafel polarization techniques. The force of adhesion between the coat and the substrates was measured in pounds per square inch. A nanoindentation test was also used to measure the hardness of the coating layer. The PVDF/Al2O3 coated steel showed a significantly higher water contact angle and lower contact angle hysteresis, reaching 157 ± 2° and 7 ± 1°, respectively, compared to the coated aluminum and glass substrates. Corrosion test results showed that the superhydrophobic PVDF/Al2O3 coatings had a much higher corrosion protection efficiency for steel and aluminum than that of the PVDF ones. The PVDF/Al2O3 coated substrates showed moderate but still acceptable adhesion between the coating layer and the substrates. Moreover, the PVDF/Al2O3 coatings had much better mechanical properties than the PVDF only coatings. Such type of coating could be a promising candidate for possible industrial and civil applications.

Network structure-based decorated CPA@CuO hybrid nanocomposite for methyl orange environmental remediation.

A unique network core-shell hybrid design-based cross-linked polyaniline (CPA), which was coated with CuO nanoparticles (NPs) and decorated with nitrogen-doped SWCNT/GO/cellulose N-SWCNTS-GO-CE, has been fabricated using the oxidative polymerization technique. This hybrid nanocomposite shows excellent photocatalytic degradation and an acceptable adsorption capability for Methyl Orange (MO) dye in aqueous solutions with a very slight effect for the N-SWCNTS-GO-CE CuO component. The prepared nanocomposites were used for the removal of a carcinogenic and noxious dye, Methyl Orange, from aqueous samples under various adsorption conditions. Approximately 100% degradation of 10 mg/L of Methylene orange dye was observed within 100 min at pH 6.0 using 50 mg/L CPA/N-SWCNTS-GO-CE/CuO nanocomposite under UV radiation. Additionally, significant factors were investigated on the degradation process including the contact time, MO initial concentration (Ci), solution pH, and dosage of the CuO nanocomposite. All investigated experiments were performed under UV radiation, which provided significant data for the MO degradation process. Furthermore, the recovery of the nanocomposite was studied based on the photocatalytic process efficiency. The obtained data provide the high opportunity of reusing CPA/N-SWCNTS-GO-CE/CuO nanocomposite for numerous photocatalytic processes. The CPA/N-SWCNTS-GO-CE/CuO nanocomposite was prepared via chemical oxidative copolymerization of polyaniline (PANI) with p-phenylenediamine (PPDA) and triphenylamine (TPA) in the presence of N-SWCNTS-GO-CE and CuO NPs. The morphology, structure and thermal properties of the CPA/N-SWCNTS-GO-CE/CuO nanocomposite were investigated using various techniques, including FTIR, XRD, RAMAN, SEM, MAP, EDX, TEM, TGA and DTG. Therefore, CPA/N-SWCNTS-GO-CE/CuO nanocomposite can be effectively used as a convenient and reusable adsorbent to remove hazardous dye from wastewater.

Ratiometric ultrasensitive optical chemisensor film based antibiotic drug for Al(III) and Cu(II) detection.

Herein, we developed and designed a novel ratiometric optical chemisensor film for determining Al(III) and Cu(II) in low concentration ranges. The chemisensor film consists of (a) antibacterial drug Ciprofloxacin (CPFX) [1-cyclopropyl-6-fluoro1,4-dihydro-4-oxo-7-(piperaziny-l-yl) quinolone-3carboxylic acid] and (b) a reference dye 5,10,15,20- tetrakis (pentafluorophenyl) porphyrin (TFPP) in a polyvinyl chloride (PVC) matrix. PVC was applied as a homogeneous system for mixing CPFX and TFPP. The emission intensity of the CPFX in the PVC matrix varies depending on the concentrations of the Al(III) and Cu(II) ions. When the sensor film is immersed in different Al(III) concentrations, a significant fluorescence enhancement of the CPFX at (427 nm) is observed. Furthermore, the fluorescence intensity of the red emission of the TFPP dye at (644 nm) does not alter. However, in the presence of Cu(II) ions, a considerable emission quenching of the CPFX peak at (427 nm) is observed. PVC provides a great permeability and penetration facilities of dissolved ions that make the sensor film sensitive to Al(III) or Cu(II) changes outside the matrix. The film displays immense sensitivity depending on their distinctive optical characteristics of CPFX and detection capabilities within a low detection limit LOD for Al(III) and Cu(II). The LOD values were estimated to be 2.05 x 10-7 M and 1.04 x 10-7 M respectively with a relative standard deviation RSDr (1%, n=3). Density functional theory (DFT) and the time-dependent DFT (TDDFT) theoretical calculations were performed to study Cu(II) and Al(III) complexation structures and their electronic properties in solution and in the sensor film. The interference of the chemisensor film was examined using different cations and the chemisensor provides significant selectivity. We develop a new ratiometric chemisensor based on PVC polymer film for Al(III) and Cu(II) detection.

A simple, quantitative method for spectroscopic detection of metformin using gold nanoclusters.

We synthesized bovine serum albumin (BSA)-stabilized gold nanoclusters (BSA-GNCs) and confirmed their ultra-small size using HRTEM (High-resolution Transmission Electron Microscope) and DLS (Dynamic Light Scattering). The fluorescence intensity of BSA-GNCs is "turned off" in the presence of Cu(II) metal ions. The resulting Cu(II)-mediated BSA-GNCs were utilized to detect metformin, a drug used to control diabetes. Metformin binds to and displaces Cu(II) ions from the BSA on the surface of the nanoclusters, which turns on the fluorescence of the nanoclusters. The interactions between the protein-stabilized nanoclusters were investigated in the absence and presence of Cu(II) using circular dichroism (CD) and Fourier-transform infrared spectroscopy (FTIR). Cu(II)-quenched BSA-GNCs had an extremely high sensitivity to detect metformin, with a low limit of detection (LOD) of 0.068 µM and a dynamic range of limit of quantification (LOQ = 10/3 LOD) of 0.22 to 11 µM. The ability of this novel "turn-on" nanosensor to detect metformin in human serum and urine samples was confirmed: the percentage recovery in fluorescence for spiked analyte ranged from 96.00-98.50% and 92.60-96.62% in human serum and urine samples, respectively. Thus, BSA-GNCs provide a valid, sensitive, specific fluorometric methodology for the detection of metformin in biomedical applications.

Novel eco-friendly amino-modified nanoparticles for phenol removal from aqueous solution.

Herein, the impact of using dried Caulerpa prolifera nanoparticles and silica-coated Caulerpa prolifera nanoparticles for the removal of phenol from aqueous solution has been investigated. The chemical structure and morphology of both dried Caulerpa prolifera nanoparticles and silica-coated Caulerpa prolifera nanoparticles were characterized by using Fourier-transform infrared spectroscopy (FTIR), Brunauer Emmett Teller (BET), scanning electron microscopy (SEM), and transmission electron microscope (TEM). Batch mode experiments were conducted depending on adsorbent dosage, pH, contact time, and initial phenol concentration. In order to investigate the adsorption mechanism of the phenol molecules to the surface of the nanoparticles, kinetic models including pseudo-first-order, pseudo-second-order, and intra-particle diffusion models were executed. To describe the equilibrium isotherms, Langmuir and Freundlich isotherms were analyzed. However, the Langmuir isotherm model was agreed to be more significant with the obtained experimental data.

Optical sensor film for metribuzin pesticide detection.

We present a new ratiometric and colorimetric optical sensor film for detection one of the most prevalent pesticide metribuzin. The detection proceeds within the low concentration range between 0 and 1.5 µM. The optical film is based on (a) near infrared (NIR) dye 2-[2-[2-Chloro-3-[2-[1,3-dihydro-3,3-dimethyl-1-(4-sulfobutyl)-2H-indol-2-ylidene]-ethylidene]-1-cyclopen-ten-1-yl]-eth-enyl]-3,3-di-methyl-1-(4-sulfobutyl)-3H-indolium hydroxide and (b) upconverting nanoparticles UCNPs of the NaYF4:Yb,Er type (diameter ~40-100 nm) that can be emitted a dual (green and red) emission under 980 nm laser diode excitation. Commercially available polyvinyl chloride (PVC) was utilized as a homogeneous matrix for immobilizing NIR dye and UCNPs. The color of the NIR dye in the PVC matrix is based on the concentration of the metribuzin. When the sensor film is exposed to metribuzin the color changes from green to blue with a significant blue shift in the absorption peak (656 nm) of the NIR dye. Furthermore, the quenching of the red emission (659 nm) of the UCNPs is proceeded due to an inner filter effect. Thus, increasing the metribuzin concentration causes the red emission of UCNPs to be reduced. Conversely, the green emission (545 nm) of the UCNPs persists uninfluenced by metribuzin and can act as a reference signal. This optical sensor film provides great sensitivity based on their unique luminescence properties of UCNPs and recognition abilities within a very low detection limit for the metribuzin LOD 6.8 × 10-8 M with a linear range of 0.23 to 1.5 µM and a relative standard deviation RSDr (1%, n = 3). The novel optical sensor was applied to the detection of metribuzin in real water samples (surface and ground waters). The sensor film exhibits great selectivity in presence of different types of ions and pesticide molecules. But, atrazine pesticide interferes the analytical signal of the sensor film due to the presence of reactive amino groups in its structure. Memorably, we report the first optical chemical sensor film based on polymer film for metribuzin detection.