Maximum Absorption Wavelength Research Articles

Development and Validation of a UV Spectroscopic Method to Estimate Eltrombopag Olamine along with Bulk and In-house Formulation

The current UV Spectroscopic method developed involving ethanol as a solvent is simple, fast, specific, precise, and sensitive for the estimation of Eltrombopag Olamine in bulk in day-to-day analysis. As per the ICH Q2 (R1) guideline, the method was validated. Eltrombopag Olamine is a drug used to treat thrombocytopenia (a low blood platelet count) in adults and youngsters with chronic immune idiopathic thrombocytopenic purpura that didn't get well with different treatments. Eltrombopag Olamine is additionally accustomed to treating severe aplastic anemia. It’s conjointly being studied within the treatment of different conditions and kinds of cancer. Eltrombopag Olamine binds to the thrombopoietin receptor, which causes the bone marrow to create more platelets. It’s class of thrombopoietin receptor agonists, also known as Promacta. Eltrombopag is also recently approved (2012) for the treatment of thrombocytopenia in a patient with chronic hepatitis C to start and sustain interferon-based therapy. The solvent used in the entire method development and validation was ethanol. The maximum wavelength of absorption was found to be 423nm. Beer’s law was obeyed in the concentration range of 5 to 30ug/ml with a correlation coefficient of 0.9966. The method was precise with an RSD of less than 2%, the LOD, and LOQ were found to be 6.18ug/ml and 18.7ug/ml respectively, % recovery of the drug is 98 to 100%. The method was validated for linearity, precision, accuracy, and robustness and all parameters were found to be satisfactory which proves that this method can be used for routine analysis of Eltrombopag Olamine.

Novel bis-chalcone-based carbazole derivative photoinitiators for visible light polymerization with good photobleaching and biocompatibility

Four novel bis-chalcone-based carbazole derivative photoinitiators (2E,5E)-2,5-bis((9-phenyl-9H-carbazol-3-yl)methylene)cyclopentan-1-one (KZA), 2,5-bis((E)-4-(9H-carbazol-9-yl)benzylidene)cyclopentan-1-one (KZB), (2E,5E)-2,5-bis((9-ethyl-9H-carbazol-3-yl)methylene)cyclopentan-1-one (KZC) and (2E,5E)-2,5-bis((5-(9-ethyl-9H-carbazol-3-yl)thiophen-2-yl)methylene)cyclopentan-1-one (KZD) were successfully designed and synthesized. Their maximum absorption wavelengths were 440 nm, 405 nm, 446 nm and 500 nm, respectively, and they all had high molar extinction coefficients. Furthermore, three-component photoinitiation system including bis-chalcone/iodonium/amine could quickly and efficiently trigger the photopolymerization of acrylates. For example, PEGDA coatings could cure in 10 s and the CC bond conversion exceeded 90 % in the end. Then we also conducted photosteady-state degradation, fluorescence quenching, cyclic voltammetry and ESR experiments to investigate the mechanisms of photopolymerization. Besides, all four bis-chalcones showed good photobleaching and biocompatibility, which was suitable for use in 3D printing and deep coating curing. For instance, the LCD 3D printer successfully printed clear and photobleached objects with KZD/iodonium/amine system. All these excellent properties indicated the industrial application potential of the four carbazole derivatives in visible light curing.

Convenient and facile theoretical design strategy to amplify NLO response of N‐doped‐indolo[3,2,1‐jk]carbazole push–pullA‐π‐D‐π‐A switches

AbstractBACKGROUNDNonlinear optical (NLO) materials play a crucial role in various technological fields, making it important to develop strategies that enhance their properties. This research paper focuses on the design strategy to enhance the NLO response of indolo[3,2,1‐jk]carbazole‐based N‐doped fused‐ring electron acceptors as its five new A‐π‐D‐π‐A switches.RESULTSThe chromophores IC1–IC5 were studied for their electronic, NLO, charge transfer, UV–visible and natural bond orbital‐related features. Their energy levels were determined, with IC1 having the highest energy (3.12 eV) and IC5 the lowest energy (1.916 eV). Their corresponding maximum absorption wavelengths (λmax) were determined to range from 398 to 647 nm. Their electronegativity (x), chemical potential (μ), hardness (η), softness (σ) and electrophilicity of the chromophores were also analyzed, having values ranging from 3.00 to 3.47 eV, 47 to −3.0 eV, 0.25 to 1.39 eV, 0.36 to 2.04 eV and 3.23 to 23.81 eV, respectively. The η and σ values indicated the stability and reactivity of the chromophores, with IC1 having the lowest η and highest σ values. IC2 had the highest dipole moment (μtot) (9.23D) and hyperpolarizability (β0) of 10.323 × 10−11 esu, indicating its strong NLO response. Among all, chromophore IC1 demonstrated a robust stabilization energy by its (N1) → (C15–C17)π* transition.CONCLUSIONThe proposed theoretical design strategy successfully amplifies the NLO response of N‐doped‐indolo[3,2,1‐jk]carbazole switches to open up possibilities for the development of advanced NLO materials, paving the way for future applications in photonics, optoelectronics and other emerging technologies. © 2023 Society of Chemical Industry (SCI).

Synthesis, photophysical properties and nonlinear response of a bisquinoline A-D-A with aggregation-induced emission for potential application in optoelectronic devices

The present work reports the synthesis and characterization of a bisquinoline (BQT) with very attractive aggregation-induced emission (AIE) and optical nonlinear response. BQT was characterized by FTIR spectroscopy and mass spectrometry to confirm the product obtained. Linear optical characterization was performed using UV-Vis and fluorescence spectrophotometry. Maximum absorption and emission wavelengths of 408 nm and 539 nm, respectively, were determined in solution; the optical band gap on the film is 1.95 eV. BQT exhibits aggregation-induced emission (AIE), a property exhibited by some fluorescent molecules that broaden the range of applications in which they can be used. BQT exhibits two-photon absorption with a negative nonlinear refractive index. This response is associated with the charge transfer processes that favour the A-D-A architecture of the molecule. Their HOMO and LUMO energy levels (-5.39 eV and -3.67 eV, respectively) and electrochemical band gap (-1.72 eV) were determined by cyclic voltammetry; these values indicate that BQT is an attractive organic semiconductor which energy levels could match those required for photovoltaic applications. The results suggest that BQT is an attractive material for its application in optoelectronic devices such as OLEDs and nonlinear optical applications.

Modeling of a Broadband Microwave Composite Thin Film Absorber.

Composite thin film absorbers show superior performance and have a wide range of applications. Obtaining a broadband composite thin film absorber is a challenge. In this work, we proposed a modeling of a broadband microwave composite thin film absorber based on the impedance matching theory and equivalent circuit model of the square loop. The unit cell of the absorber was composed of metal square loops with high magnetic conductivity deposited on the polyethylene substrate, and an FR-4 (epoxy glass cloth) substrate was the spacer substrate layer. The simulation results show that the absorptivity of the absorber reached more than 90% in the frequency range of 8.7-18 GHz for TE and TM waves under normal incidence. The thickness of the designed absorber was 2.05 mm (0.059 λmax, λmax corresponds to the maximum absorption wavelength). The simulation results show that the energy distribution in the proposed absorber was mainly localized in the top metal FSS layer due to the ohmic loss of metal, and the dielectric loss played a small role in the absorption of the absorber. Our work provides a design approach to improve the efficiency of optoelectronic devices and thermal detectors and has application prospects in radar and aircraft stealth applications.

Novel strategy toward color-tunable and glow-in-the-dark colorless smart natural wooden window

Smart windows that use photochromic colorless wooden materials are an intriguing and urgent area of research. Herein, we create afterglow transparent woods with UV-induced photochromic capability. Infiltrating a lignin-modified wood (LMW) with a solution of methyl acrylate (MA) and rare-earth strontium aluminum oxide (SrAl2O4: Eu2+, Dy3+; SAOED) yielded afterglow and photochromic translucent wood. Preparing photoluminescent transparent wood effectively requires dispersing SAOED phosphor nanoparticles (NPs) in pre-polymerized MA without clumping. CIE (Commission Internationale de ĺEclairage) Lab colorimetric studies indicated that this transparent timber substrate changed color from colorless in daylight to greenish when exposed to ultraviolet rays. Micrographs taken using a transmission electron microscope (TEM) were analyzed to learn more about the morphology of the synthesized SAOED NPs. Different characterization techniques were applied on the photochromic translucent wood samples, including scanning electron microscopy (SEM), energy-dispersive X-ray analyzer (EDX), hardness properties, wavelength-dispersive X-ray fluorescent spectroscopy (WD-XRF), and absorption and emission spectroscopy. Absorption maximum wavelength was detected at 365 nm. Both 436 nm and 517 nm were observed as emission wavelengths in the developed photoluminescence wood. The results displayed that the manufactured transparent wood introduced superior protection from UV radiation and superhydrophobic activity. UV light triggered a rapid and reversible photochromic reaction in the transparent luminous wood.

Theoretical study of static and frequency-dependent nonlinear optical properties of 1-phenyl-2,5-di(thiophen-2-yl)-1H-pyrrole based D-π-A chromophores through π-linkers modifications: A gateway towards giant nonlinear optical compounds

Designing materials with proficient nonlinear optical (NLO) amplitudes is the frontier area of research. To address the briskly mounted demand for potentially useful NLO materials in optoelectronic and electrical applications, static and frequency-dependent NLO response properties of 1-phenyl-2,5-di(thiophen-2-yl)-1H-pyrrole (PDTP) based D-π-A chromophores were computed at 1907.21 nm, 532 nm, and 1064 nm laser wavelength for exploring SHG β (−2ω, ω, ω) and EOPE β (−ω, ω, 0). The PDTP-based organic dye (MC28) is selected to serve as a reference, and the quantum chemical models of its ten derivatives (SLN1-SLN10) are constructed by incorporating a variety of previously reported π-linkers into the reference. DFT and TD-DFT calculations reveal that π-linker modification tunes the NLO characteristics in SLN1-SLN10. The photophysical, electronic aspects, molecular electrostatic potential (MEP), frontier molecular orbital (FMO), density of state (DOS), transition density matrix (TDM), natural population analysis (NPA), and frequency-dependent NLO response properties of investigated dyes were evaluated. Giant NLO responses due to a much lower energy gap than the reference dye was found in SLN1-SLN10 confirmed by FMO analysis. UV–Vis analysis determined that the maximum absorption wavelength of the studied dyes was in the visible spectrum (383–413 nm). The proposed dye’s active NLO sensitivity and charge separation state was shown to have resulted from the migration of electrons from D to A via π-linkers using natural population analysis (NPA) analysis. In addition, molecular electrostatic potential (ESP), electron localization function (ELF), and localized orbital locator (LOL) topological assessments are carried out to evaluate the transfer of charge that takes place within SLN1-SLN10 as well as high NLO features. Maximum values of linear polarizability (αo) and first-hyperpolarizability (βo) were calculated to be 5.64 × 102 a.u. and 1.89 × 104 a.u., respectively in SLN3. At 1907.21 nm, SLN3 with terthiophene linker showed a remarkable SHG β(−2ω,ω,ω) and EOPE β (−ω,ω,0) response of 2.60 × 104 a.u. and 2.09 × 104 a.u. respectively. The theoretical structure provided conclusive evidence that the dyes under investigation possess excellent static and NLO potential at different laser wavelengths and should be considered for use in future NLO applications.

Methods Development and Validation for the Estimation of Pioglitazone HCl in Bulk and Formulations by UV Spectroscopy and FTIR

The use of spectroscopic analysis, particularly UV spectrophotometer, is a simple and essential technique for bulk drug estimation, formulation studies, and compatibility assessments of drugs with various excipients. In the pharmaceutical industry, various analytical instruments, including Fourier transform infrared spectroscopy (FTIR), are employed for investigating drug-excipient interactions that can impact the stability of active pharmaceutical ingredients. This study aimed to develop a UV spectrophotometric method for the analysis of Pioglitazone hydrochloride in phosphate buffer (pH 7.4) and methanolic solution, assessing its linearity and compliance with Beer's Law. Furthermore, we aimed to use FTIR to characterize potential interactions between Pioglitazone and common pharmaceutical excipients, such as Guar Gum, Chitosan, and Sodium Alginate. Standard solutions of Pioglitazone were prepared in phosphate buffer (pH 7.4) and methanol. UV spectrophotometer was conducted to determine the maximum absorption wavelength. Calibration curves were constructed to evaluate linearity and adherence to Beer's Law. FTIR analyses were performed to investigate drug-excipient interactions by examining the functional groups. In phosphate buffer (pH 7.4), the maximum absorption wavelength for Pioglitazone hydrochloride was 268 nm. The calibration curve for Pioglitazone in phosphate buffer (pH 7.4) demonstrated linearity in the concentration range of 1–20 µg/ml, with a correlation coefficient of 0.998. In methanol, the maximum absorption wavelength for Pioglitazone hydrochloride was found to be 272 nm. The calibration curve in methanol exhibited linearity in the range of 1–20 µg/ml, with a correlation coefficient of 0.999. FTIR analysis revealed potential drug-excipient interactions, particularly in the case of Guar Gum, Chitosan, and Sodium Alginate, suggesting the formation of stable hydrogen bonds. The developed UV spectrophotometric method for Pioglitazone analysis is a reliable, cost-effective, and reproducible approach, making it a valuable tool for drug development and quality control. Additionally, the FTIR characterization confirmed interactions between Pioglitazone and common pharmaceutical excipients, enhancing our understanding of formulation compatibility.

Role of extended end-capped acceptors in non-fullerene based compounds towards photovoltaic properties

Fullerene free organic solar cells (OSCs) have found at the forefront in the photovoltaic sector due to effective optical and electronic characteristics. The quantum chemical investigation focused on the designing of pentacyclic aromatic bislactam based chromophores for highly efficient OSCs. A series of eight molecules (PCLMD1–PCLMD8) was designed from reference compound (PCLMR), with A2–π–A1–π–D–π–A1–π–A2 configuration via end group redistribution with benzothiophene based acceptors. Through benchmark study of UV–Vis between simulated and experimental values of PCLMR, MPW1PW916-31G(d,p) functional was selected of DFT approach. Various analyses such as absorption properties (UV–Vis), frontier molecular orbitals analysis (FMOs), transition density matrix (TDM), open circuit voltage (Voc) and density of state (DOS) were performed in order to explore the photovoltaic properties of above-mentioned chromophores. Modification of peripheral acceptors brought about significant changes in their charge-transfer properties. These alterations resulted in reduced exciton binding energy (Eb) ranging from 2.277 to 2.087 eV, a narrower bandgap (Eg) ranging from 1.746 to 1.868 eV and an increased maximum absorption wavelength (λmax) ranging from 829 to 882 nm in the solvent phase. These values were observed in comparison to PCLMR, which had an Eb of 2.443 eV, an Eg of 1.895 eV and λmax at 813 nm. The FMO analysis indicated a significant charge distribution across HOMO-LUMO in the designed chromophores. Furthermore, the rates of electron and hole mobility as well as the open-circuit voltage (Voc) were higher for all the benzothiophene acceptor-based molecules (PCLMD1–PCLMD8) than that of PCLMR. The analysis showed that the integration of benzothiophene acceptors with electron-withdrawing groups amplifies charge transfer towards acceptor components, leading to heightened JSC and Voc values in organic solar cells (OSCs). This phenomenon is attributed to the decrease in the energy level of the lowest unoccupied molecular orbital (LUMO), while the highest occupied molecular orbital (HOMO) remains mostly unchanged, along with the effective broadening of the absorption spectrum. Hence, it can be concluded that by employing molecular engineering with benzothiophene acceptor moieties, the efficiency of photovoltaic materials based on NF compounds could be improved.

Dopamine as a polymerizable reagent for enzyme-linked immunosorbent assay using horseradish peroxidase

We demonstrate that dopamine can be used as a reagent for colorimetric enzyme-linked immunosorbent assay (ELISA) using horseradish peroxidase (HRP). Dopamine was able to be polymerized in the presence of HRP and H2O2, and black polydopamine was obtained after the enzymatic reaction. Because of the black color, the absorbance was significantly changed in the whole range of the visible light region. Here, an indirect competitive ELISA based on the polymerization of dopamine was performed to detect a fluoroquinolone antibiotic, enrofloxacin. The antibiotic is commonly used in livestock farming. The anti-antibiotics antibody was produced from egg yolk from chicken hens. In the visible range, sufficient absorbance changes of ∼0.4∼0.5 and a low background level for the ELISA response were obtained, and the 50 % inhibitory concentration value at 450 nm was determined to be 26 ppb. The performance of the indirect competitive ELISA based on the polymerization of dopamine was compared to that based on the oxidation of catechol because dopamine has a catechol skeleton. By the complex of HRP and H2O2, catechol can be oxidized to o-benzoquinone having a maximum absorption wavelength of 420 nm. It was shown that the absorbance change in the case of polydopamine was about 2.5 times higher than that of catechol, where the background levels were similar. This confirms that the polymerization of dopamine significantly enhanced the photosignal.

Novel fluorescent sensors based on coumarin-hydrazide-hydrazone hybrid for the detection of CN−, Co2+ and Ni2+ ions: DFT and bioimaging in living cells

Novel coumarin-hydrazide-hydrazone hybrids, (E)-7-(diethylamino)-N′-(2-hydroxy-3-methoxybenzylidene)-2-oxo-2H-chromene-3-carbohydrazide (1) and (E)-7-(diethylamino)-N′-(4-(diethylamino)-2-hydroxybenzylidene)-2-oxo-2H-chromene-3-carbohydrazide (2), were synthesized and investigated their chemosensor properties. The sensors showed recognition properties of CN−, Co2+, and Ni2+ ions. After interaction with the cyanide anion, the coumarin-hydrazide-hydrazone sensors exhibited a color change visible to the naked eye, from yellow to colorless under daylight and from blue to green under UV light. The sensors exhibited a significant fluorescent enhancement response to the cyanide anion by the intramolecular charge transfer (ICT) mechanism. Furthermore, the recognition of cations was observed by the redshift of the emission band based on the complexation mechanism of Co2+ and Ni2+ ions with the sensors. Sensor 1 showed that CN− and Ni2+ ions could be detected at a limit of detection (LOD) of 0.187 μM and 0.169 μM, respectively, while sensor 2 showed that Co2+ anion could be detected at a LOD of 0.177 μM. Anion and cation recognition mechanisms were also investigated by Density Functional Theory (DFT) analysis for the sensors. Cell viability and proliferation-based cytotoxicity (MTT) and live cell imaging assays of sensor 2 were performed to elucidate whether it could be used as cell bioimaging. It was determined that sensor 2 was not cytotoxic against the A549 cell line at the concentrations where it could act as a chemosensor for the detection of CN−, Co2+, and Ni2+ ions, and it penetrated into the cell and accumulated around the nucleus. These properties of sensor 2 indicate that it can be used as a potential sensor in cell imaging systems. In addition, the photophysical properties of the sensors in various solvents with different polarities were investigated using spectroscopic techniques for absorption and emission maximum wavelengths. The thermal stability of the sensors was determined by Thermal Gravimetric Analysis (TGA), and it can be said that the theoretical and experimental studies are in perfect harmony.

A UV Spectrophotometric method for simultaneous determination of Ibuprofen and Paracetamol concentration in suspensions


 
 
 INTRODUCTION: Paracetamol is a standard antipyretic and analgesic which is widely used since the 19th century. Currently, paracetamol is the first-line treatment for pain management of different types. Ibuprofen, on the other hand, is an antipyretic and an analgesic. It is safe and has been used in the treatment of a number of conditions including mild to moderate pain, dysmenorrhea, inflammations and fever to name few.
 METHODS: This study aimed at developing and validating a simultaneous UV spectrophotometric method for analysis of ibuprofen and paracetamol in fixed-dose combination suspensions. The proposed method is based on the simultaneous equation principle, which involves measurement of absorbance at wavelengths of maximum absorbance for ibuprofen and paracetamol. The method was validated for linearity, accuracy, repeatability, intermediate precision and robustness as per USP and ICH guidelines.
 RESULTS: The two molecules showed wavelength of maximum absorbance at 222 nm and 243 nm for ibuprofen and paracetamol respectively, using phosphate buffer as a diluent. The method was also linear (R2≥0.995), precise (RSD ≤ 2), and robust with accuracy ranging between 98.1%-105% and 109.8 %- 134.9% for paracetamol and ibuprofen, in the range of 0.0032 – 0.0048 mg/ml for ibuprofen and 0.004-0.006 mg/ml for paracetamol, respectively.
 CONCLUSION: We have developed an accurate and robust method which can be used to analyze quantitatively paracetamol in suspensions which contain both paracetamol and ibuprofen. The limits of quantification of this method cover the concentration range recommended by the USP (80%- 120%), which justifies the application of the method in routine analysis.
 
 

Photovoltaic and Optical Characterization of Organic Heterocyclic 6,6′‐Dibromoindigotin Crystal Under Changing Solvent Polarity by DFT Analysis

AbstractThe photovoltaic and optical properties of 6,6′‐dibromoindigotin (DBI) crystal under changing solvent polarity are investigated through DFT analysis. It includes geometry optimization, global reactivity, UV–vis analysis, open circuit voltage (Voc), FMOs, and NBO analysis. The highest HOMO‐LUMO gap (Egap) value is found for the gaseous phase (1.82 eV), while the lowest Egap is found for dichloro methane (1.64 eV), and intermediate values with the other solvents. The molecule has a high IP of 2.48 eV, low EA of 0.74 eV, moderate polarity, and hardness (η). The maximum absorption wavelengths (λmax) of the compound in different solvents are dichloromethane and DMSO (373 nm), chloroform (372 nm), methanol and water (371 nm), toluene (367 nm), and gaseous (356 nm). Their Voc range is 0.2–0.28 eV. Among all, chloroform demonstrates the highest performance with a fill factor (FF) of 0.8630, normalized open circuit (Nor. Voc) of 31.69 eV, and Jsc of 26.47 mA cm−2. Toluene also shows promising results with an FF of 0.8060, Nor. Voc of 19.71 eV, and Jsc of 21.19 mA cm−2. Water, although not as effective as other solvents, still exhibits respectable values with an FF of 0.8315, Nor. Voc of 23.96 eV, and Jsc of 24.63 mA cm−2.

Importance of solvents role in molecular and electronic properties, DFT, spectroscopic, electron-hole transition, chemical reactivity, topology and molecular docking investigations of (±)-2-(2-{4-[(4-chlorophenyl)-phenylmethyl] piperazin-1-yl} ethoxy)ethanol

The phenyl-substituted piperazine derivative molecule was taken into consideration in the current investigation of the organic drug molecule (±)-2-(2-{4-[(4-chlorophenyl)-phenylmethyl] piperazin-1-yl} ethoxy) ethanol (CPE), evaluating the spectral characterization using both simulated and recorded FT-IR, FT-Raman, and UV spectral studies. The theoretical computations have been conducted using DFT/B3LYP/6–311++G(d,p)as a basis set. The stable optimized structure was attained by selecting suitable dihedral angles using PES analysis and molecular geometrical parameters were obtained and matched with the available literature data. The vibrational assignments along with the PED contributions were obtained and matched with the recorded values. The electronic properties were analyzed for the various solvents and found that acetone possesses a lesser band energy gap of 5.3637 eV implies the stability of the header composite. Further, the UV–Vis spectra for the various solvents and corresponding parameters were obtained along with excitation analysis with electron-hole isosurface contributions. The maximum absorption wavelength of the CPE obtained in the liquid phase and the recorded wavelength compared with the simulated data. Intermolecular reliability of the molecule emanating from hyperconjugative interactions of charge delocalization by NBO analysis. The accomplishment of nucleophilic and electrophilic regions of the solvents such as acetone, water, and DMSO was implemented using Molecular Electrostatic Potential (MEP) for the molecule. Electron localization function (ELF) Localized orbital locator (LOL) and Reduced density Gradient (RDG) were attained using the above-mentioned basis set for the topological behavior of the title molecule. According to molecular docking studies, the amino acid residues present at the active site region of the ligand (CPE) are particularly suited to Histamine N-methyltransferase (HNMT) with suitable targets (PDB: 2AOT,1JQD, and 2AOU) and the minimum binding energy for the receptor target is 2AOU is −6.90 kcal/mol respectively.

Impact of bimetal doping on the structural and optical characteristics of copper oxide nanoparticles to enhance photocatalytic degradation of dyes: an investigative study

Metal oxide nanoparticles have attracted a lot of attention for dye degradation applications as they have better light absorption properties required for the photocatalysis. This paper presents the impact of bi-metal doping (i.e. Cerium and Tungsten) on the structural and optical properties of Copper oxide nanoparticles. Bi-metal doping has shown remarkable impact on the optical properties (i.e. enhanced light absorption) of CuO nanoparticles making it suitable for photocatalytic applications. A simple co-precipitation method was used to synthesize the pure, single-metal doped and bi-metal doped (i.e. Ce, W and Ce-W) CuO nanoparticles. XRD analysis was done to study the structural properties along with crystallite size estimation using Debye-Scherer formula. Absorption band at 852 cm−1 and 650 cm−1 in the FT-IR spectra further confirmed the presence of CeO2 & WO2 in the monoclinic phase of CuO nanoparticles. Maximum absorption wavelength and bandgap are measured using UV–vis Spectroscopy, and it has been observed that both these quantities depend upon the choice of dopant and can be tailored just by choosing the appropriate dopant. The paper presents an extensive analysis using experimental study to compare the impact of Ce, W and bimetal (Ce-W) doping on the structural, optical and photocatalytic properties of CuO nanoparticles. Enhanced optical absorption in the complete visible range is observed in case of bi-metal doped CuO nanoparticles making it a promising candidate for photocatalytic dye degradation application.

Analyzing Biomarkers in an Enhanced Polyherbal Formula with Antidiabetic Attributes through High-performance Thin-layer Chromatography and Liquid Chromatography–Mass Spectrometry/ Mass Spectrometry

ABSTRACT Context: In this research, we subjected a polyherbal formulation (PHF) prepared in-house, previously evaluated for its antidiabetic effects in streptozotocin-induced diabetic rats, to further analytical characterization using high-performance thin-layer chromatography (HPTLC) and Liquid Chromatography coupled with Tandem Mass Spectrometry (LC-MS/MS). Aim: The aim of this research was to measure the active components within a newly developed in-house PHF with antidiabetic properties, prepared using dried leaves of Tinospora cordifolia, dried bark of Cinnamomum zeylanicum, dried seeds of Trigonella foenum, and dried seeds of Nigella sativa, employing HPTLC and LC-MS/MS techniques. Materials and Methods: Magnoflorine (MAG), cinnamaldehyde (CIN), trigonelline (TRI), and thymoquinone (THY) were identified as the active components of the ethanolic extract of the PHF. We utilized HPTLC and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for the characterization of these constituents. The gradient mobile phase consisted of water, acetonitrile, and 0.1% trifluoroacetic acid. Chromatographic separation was achieved using an XBridge C18, 250 × 4.6, 3 mm analytical column with a flow rate set at 1.0 mL/min, maintained at ambient temperature employing a gradient system that spanned 30 min. Mass scanning was conducted in positive mode, with a scan speed ranging from 100 to 2000 amu/s, covering a mass range from 20 to 1974 Da. Electron spray ionization mode was utilized, with a source temperature maintained at 150°C and a desolvation temperature at 350°C. For HPTLC separation, precoated silica gel 60 GF254 plates were employed, employing a mobile phase consisting of toluene/chloroform/ethyl acetate/methanol/formic acid in a ratio of 2.5:2.5:2.5:2.0:0.5 (v/v). The plates were developed at room temperature, extending to a distance of 9.0 cm. Each individual component (MAG, CIN, TRI, and THY) was scanned and quantified at its respective maximum absorption wavelength (237 nm, 259 nm, 305 nm, and 338 nm). Results: Experimental parameters such as band size, chamber saturation duration, solvent front migration, slit width, and others were carefully examined to determine the optimized chromatographic conditions. LC-MS analysis of the alcoholic extract of the PHF successfully identified the presence of all five bioactive chemical constituents, namely, MAG, CIN, TRI, and THY. In addition, the drug samples exhibited satisfactory resolution with retention factor values of 0.27 ± 0.01, 0.64 ± 0.01, 0.55 ± 0.01, and 0.92 ± 0.01 for CIN, MAG, TRI, and THY respectively, using HPTLC. Conclusion: The integration of Ayurvedic formulations with contemporary high-throughput screening techniques holds great promise in discovering more potent and biocompatible drug leads. The results of this study offer compelling scientific evidence that strengthens the case for the therapeutic utility of the PHF, further underscoring its significance in the field of health care.

Eumelanin: A natural antioxidant isolated from squid ink by new enzymatic technique and prediction of its structural tetramer

The investigation into natural eumelanin found in squid ink is an emerging research topic due to its antioxidative properties. However, the methodologies for acquiring pure eumelanin and establishing the intricate relationship between its structure and antioxidative efficacy remain limited. Novel enzyme extraction technique, termed response surface optimization, was employed to synthesize high-purity eumelanin, and its antioxidant activity was evaluated at free radical scavenging and cellular levels and correlated with detailed tetrameric structure prediction for the first time. Results demonstrated that enzymatic extraction technique yielded eumelanin (ANF) nanostructure with stability, boasting particle size of 112.35 nm, a maximum absorption wavelength of 224 nm, a ΔHpp value of 0.4802 mT, and a purity of 92%. Compared with melanin standard (MelS), ANF had superior free radical scavenging activity, eliminating 89.62% of DPPH radicals, 96.79% of superoxide ion radicals, and 93.20% of hydroxyl radicals, and better repair of cellular oxidative damage. Based on molecular energy, molecular electrostatic potential (MEP), and molecular orbitals by Gaussian calculations, the tetrameric structure (DHICA3-DHI1‴ and “DHICA3-DHI1”) with significant antioxidant activity contained inside eumelanin was anticipated. Our findings reveal its potential as a natural antioxidant, offering broad prospects for antioxidant food additives or therapeutic applications in nutritional and pharmaceutical ingredients.

Preparation, characterization, and antimicrobial activity of novel chitosan blended almond gum–nanosilica bionanocomposite film for food packaging applications

Abstract Almond gum and varied concentrations of nanosilica (0.2, 0.4, 0.6, 0.8, and 1.0 wt%) were introduced into the chitosan polymer matrix by solution cast method to enrich the characteristics of the bionanocomposite film. The surface topography, thermal stability, crystalline nature, and functional moieties of the synthesized bionanocomposite films were characterized by SEM, TGA, XRD, and FT-IR. The UV–Vis spectrophotometer showed a maximum absorption wavelength for the film containing the highest concentration of nanosilica. Change in properties such as increased tensile strength, elongation and reduced water solubility, and swelling properties were observed for the bionanocomposite film containing 1.0 wt% nanosilica. In addition, the films exhibited excellent inhibition effect against Escherichia coli bacteria and Candida albicans fungus, which were proven by well diffusion assay method. The carrot slices packed in the bionanocomposite film containing the highest amount of nanosilica retained their freshness for a longer period of time, suggesting the film to be an effective and excellent food packaging material.

Naphthyridine-based neutral fluorescent probes for dynamic monitoring lipid droplet polarity

In this paper, several novel nitrogen-containing heterocycle dyes 1a-c with large conjugated planar structures based on naphthyridine derivatives were designed and synthesized, which had excellent optical properties and biological applications. Optical test showed the maximum absorption wavelengths of 1a-c were in the range of 443–485 nm, while the maximum emission wavelengths located at 523–610 nm in difference solvents. Furthermore, they exhibited polarity related fluorescence intensity changes with high fluorescence quantum yields, even up to 88% (1a in THF). Moreover, the transient absorption spectra revealed the excited-state lifetime of dye 1a became shorter with the increase of solvent polarity. Density functional theory calculations are also used to help explain the effect of the polarity of solvents on their fluorescence properties. Interestingly, the dyes 1a-c were somewhat toxic to cancer cells, while had an obvious growth-promoting effect on normal cells. Additionally, 1a-c with excellent lipid droplet (LD) targeting could be used for long-term observation of targeted cellular lis) hysiological activity and further applied to dynamic monitoring of changes in LDs polarity stimulated by TLR4 activator (LPS) in living cells. Overall, the excellent optical properties and biocompatibility of 1a-c indicate that they can serve as fluorescent probes for biological applications, and the results have important implications for understanding the physiological functions of LDs, especially in terms of morphological and polar changes.

Tuning the Photophysical Properties of Acceptor-Donor-Acceptor Di-2-(2-oxindolin-3-ylidene) Malononitrile Materials via Extended π-Conjugation: A Joint Experimental and Theoretical Study.

Many optoelectronic applications require organic semiconductor (OSC) materials with high electron affinity. In this work, a series of novel acceptor-donor-acceptor (A-D-A) materials with low-lying LUMO energy levels were designed and characterized. In this strategy, two acceptor dyes, bis-isatin and di-2-(2-oxindolin-3-ylidene) malononitrile, were connected by various π-bridges (benzene ring, benzo[c][1,2,5]thiadiazole, monothiophene, trithiophene). We varied the length of the π-conjugation of the central core and the linkage position of the acceptor core (4- vs. 6-position of the phenyl ring) to investigate the effect on the optical and electrochemical properties of the materials. We performed density functional theory (DFT) and time-dependent DFT (TD-DFT) studies to gain insight into the dyes' electronic properties by determining the energy levels. Our findings demonstrate that with increasing acceptor strength and π-conjugation length of the core, the wavelength of the longest absorption maximum as well as their respective extinction coefficients are enhanced, which results in band-gap reduction either by lowering the LUMO and/or raising the HOMO energy level of the molecules. The potential practical utility of these materials as electron-transport materials for perovskite solar cells (PSCs) has been demonstrated.