Redshift Research Articles

Covalently Coupling Carbon Quantum Dots for Photoluminescence Red Shift Response to pH.

Conventional fluorescent pH sensors, despite offering high sensitivity and rapid response, are limited by their reliance on fluorescence intensity changes, hindering applications requiring precise wavelength control. Here, we present a pH sensing strategy based on cross-linked carbon quantum dots (CCL-CQDs) displaying a remarkable pH-dependent red shift in the fluorescence emission wavelength. Amino- and carboxyl-functionalized CQDs were synthesized via a one-step hydrothermal method and further assembled into CCL-CQDs through the condensation reaction between amino groups and glutaraldehyde. The CCL-CQDs displayed excellent pH sensitivity, with their fluorescence emission wavelength exhibiting a linear red shift upon increasing pH (from 2.29 to 7.16). The results of mechanism exploration revealed that H+ induced the cleavage of C═N bonds in the CCL-CQD structure, leading to the formation of -COOH groups and increased surface-oxidized carbon content. This enhanced oxidation generated more surface defects, triggering a wavelength shift in surface-state-related fluorescence emission. This study demonstrates the successful synthesis of pH-sensitive CCL-CQDs with an excellent fluorescence detection performance.

Live imaging of the extracellular matrix with a glycan-binding fluorophore.

All multicellular systems produce and dynamically regulate extracellular matrices (ECMs) that play essential roles in both biochemical and mechanical signaling. Though the spatial arrangement of these extracellular assemblies is critical to their biological functions, visualization of ECM structure is challenging, in part because the biomolecules that compose the ECM are difficult to fluorescently label individually and collectively. Here, we present a cell-impermeable small-molecule fluorophore, termed Rhobo6, that turns on and red shifts upon reversible binding to glycans. Given that most ECM components are densely glycosylated, the dye enables wash-free visualization of ECM, in systems ranging from in vitro substrates to in vivo mouse mammary tumors. Relative to existing techniques, Rhobo6 provides a broad substrate profile, superior tissue penetration, non-perturbative labeling, and negligible photobleaching. This work establishes a straightforward method for imaging the distribution of ECM in live tissues and organisms, lowering barriers for investigation of extracellular biology.

Spectrum and Polarization-Resolved Nonlinear Optical Near-Field Imaging of Plasmonic Nanoantennas.

Plasmonic nanoantennas, which support surface plasmon resonances enabling the concentration of electromagnetic energy into subwavelength volumes, have emerged as versatile tools for a wide range of applications. However, achieving high-resolution near-field imaging with polarization and temporal sensitivity remains a significant challenge. In this work, we present a novel nonlinear optical microscopy technique based on degenerate four-wave mixing to enable spectrum- and polarization-resolved near-field imaging of plasmonic nanoantennas. By using a mid-infrared pump and near-infrared probe, we capture detailed spatial distributions of plasmon-enhanced near-field intensity and polarization characteristics, revealing distinct polarization patterns and frequency-dependent enhancements. Our method enables the observation of resonance-induced spectral shifts and subwavelength spatial resolution, offering valuable insights into plasmonic field behaviors, particularly in the mid-infrared range. This approach provides a powerful tool for exploring and understanding the complexities of plasmonic nanostructures, with significant potential for advancing nano-optics applications.

Shedding Light on Protein Aggregates by Bisindolyl-Based Fluorogenic Probes: Unveiling Mechanistic Pathways and Real-Time Tracking of Protein Aggregation.

Herein, we synthesized a pair of oxidized bisindolyl derivatives with anthracene (probe 1) and pyrene (probe 2) fluorophores for selective protein aggregate detection, crucial in disorders like Alzheimer's disease. Probe 1 exhibited a significant "turn-on" response (∼12-fold) and concomitant red shift (∼21 nm) with lysozyme aggregates, while showing ∼3-fold fluorescence enhancement with insulin aggregates, indicating high selectivity for aggregated proteins. Probe 2 showed similar responses but with less preference, as compared to probe 1. Furthermore, the thiazole orange (TO) assay confirmed the ability of probe 1 to detect protein fibrils and monitor aggregation kinetics (with distinct responses at different phases of aggregation). Molecular docking calculations demonstrated efficient binding of probes to aggregated proteins, stabilized primarily by hydrophobic interactions (π-π stacking). Additionally, density functional theory (DFT)-based global reactivity descriptors were computed to assess the reactivity and preferential docking sites. This work underscores the potential for novel therapeutic strategies targeting protein aggregates and early diagnosis of protein disorders.

Glycosylation on the Antifreeze and Antioxidant Capacities of Tilapia Gelatin Hydrolysates

The antifreeze and antioxidant capacities of tilapia (Oreochromis mossambicus) gelatin hydrolysates were investigated, after glycosylation with saccharides of varying molecular weights, to enhance their functional properties to widen its commercial application in frozen aquatic products. Glycosylation was conducted by mixing gelatin hydrolysates with ribose, glucose, maltose, and dextran (20 kDa) at a 1:1 mass ratio; the glycosylation products had a pH of 10 and were incubated at 80 °C for 1 h. The results showed that the glycosylation degree ranked as: ribose > glucose > maltose > dextran. The mass spectrometry analysis showed that 17, 32, and 5 glycosylation sites were identified for ribose, glucose, and maltose, respectively, suggesting a molecular weight-dependent effect. Spectroscopic analyses, including ultraviolet and infrared spectroscopy, revealed that the gelatin hydrolysate structure was expanded, with chromophores in hydrophilic environments; a blue shift in the amide A and II bands confirmed that the amino group was involved. Fluorescence spectroscopy showed conformational changes with a red shift at 303.4 nm and a reduction in intensity. Antifreeze activity, such as catalase freezing protection and shrimp surimi protein stability, and antioxidant activity, including radical scavenging and metal ion chelation, were significantly improved. Ribose exhibited the strongest effects, followed by maltose and glucose. These results demonstrate the potential of glycosylation to improve gelatin hydrolysates for functional applications.

Chlorine‐Mediated Dispersion Modulates Packing Arrangement of Asymmetric Acceptors for High‐Performance Organic Solar Cells

AbstractThis study focuses on the synthesis and the performance of non‐fullerene acceptors (NFAs) with varying chlorine dispersion in organic solar cells (OSCs). Four chlorine‐mediated acceptors, BO3Cl‐a, BO3Cl‐γ, BO3Cl‐β, and BOEH3Cl‐β are synthesized with isomeric terminal groups and then integrated with donor PBDB‐TF to fabricate OSCs. It finds that increased chlorine dispersion improves device efficiency with enhanced current and BOEH3Cl‐β‐based devices achieving a power conversion efficiency (PCE) of over 19%, which is one of the highest values reported for asymmetrically chlorinated acceptors. In OSC devices, Enhanced exciton dissociation and reduced carrier recombination are observed with more chlorine dispersion, along with improved charge transport due to modulation of molecular packing in the active layer. Furthermore, transient absorption spectroscopy elucidates that chlorine dispersion augments exciton diffusion time, thereby elevating the current density of devices, while the branching strategy further amplify the exciton lifetime of BOEH3Cl‐β, preserving the value of short current in the face of spectral blue shifts of it. The findings suggest that chlorine‐mediated dispersion is a key factor in enhancing OSC performance with improved current by progressive molecular packing arrangement and aggregation behaviors.

Non-negligible Influence of Vacancies and Interlayer Coupling on Electronic Properties of Heavy Ion Irradiated SnSe2 FETs

Abstract Influences of swift heavy ion (SHI) irradiation induced defects on electronic properties of the bulk SnSe2 based FETs are explored. Latent tracks and amounts of Se vacancies in the irradiated SnSe2 were confirmed. Red shift of the A1g peak indicates that the resonance frequency of the phonons is reduced due to the defect generation in SnSe2. The source-drain current Ids increased at ion fluence of 1×1010 ions cm-2, which was attributed to the irradiation caused Se vacancies, which hence increases the concentration of conduction electrons. The carrier mobility was about 16.9 cm2V-1s-1 for the devices irradiated at ion fluence of 1 × 109 ions cm-2, which was benefit from heavy ion irradiation enhanced interlayer coupling. The mechanism of device performance optimization after irradiation is discussed in detail. This work provides evidence that, given the electronic properties of two-dimensional material-based device, vacancies and interlayer coupling effects caused by SHI irradiation should not be ignored.

Targeting Mycobacterium tuberculosis Parallel G-Quadruplex Motifs with Aminoglycosides Neomycin and Streptomycin: Spectroscopic and Calorimetric Aspects.

Mycobacterium tuberculosis (Mtb) contains potential G-quadruplex (PGQ) motifs in the genes espK and cyp51, which are crucial for the bacteria's virulence within host cells. Aminoglycoside molecules are commonly used as antibiotics for ribosomal targets. This study provides insight into the interactions between these aminoglycosides and Mtb-PGQ sequences (espK and cyp51), shedding light on the structural and thermodynamic dynamics of their binding. This study demonstrates the stability, affinity, and conformation of Mtb-PGQ in the presence of neomycin and streptomycin. Ultraviolet-visible spectroscopy (UV-vis), circular dichroism spectroscopy (CD), CD thermal melting, isothermal titration calorimetry (ITC), and fluorescence intercalator displacement (FID) assays were used to comprehensively examine these interactions. Our results reveal that neomycin with Mtb-PGQexhibits hypochromism accompanied by a 4-5 nm red shift in the UV-visible absorption titration, whereas streptomycin exhibits a hypochromic shift without changes in the maximum wavelength. Notably, neomycin shows a nonlinear binding isotherm, suggesting the involvement of more than one binding process in the formation of neomycin.Mtb-PGQ complexes. Scatchard plot analysis indicates higher binding affinity values for neomycin compared with weaker affinity of streptomycin. CD studies reveal that neomycin decreases the ellipticity of Mtb-PGQ with a red shift while retaining the parallel topology, ultimately enhancing the thermal stability of both espK and cyp51. In contrast, streptomycin destabilizes the cells. ITC analysis reveals that neomycin exhibits the strongest binding affinity for cyp51, with the relative order being NEO-cyp51 > NEO-espk > STR-cyp51 > STR-espk. Moreover, thermodynamic analysis reveals that neomycin possesses a unique dual mode of binding through grooves as well as stacking. FID studies further confirm a lower DC50 value for neomycin than for streptomycin, suggesting that neomycin is a strong displacer of thiazole orange. Thus, the results show that neomycin with amino groups selectively recognizes the grooves of cyp51 over espK.

High-Pressure Effects on an Octa-Hydrated Curium Complex: An Experimental and Theoretical Investigation.

An octa-hydrated curium compound [Cm(H2O)8](Hdtp)(dtp)·H2O (Cm1, H2dtp = 2,3-di(tetrazol-5-yl)pyrazine) along with its lanthanide analogues [Ln(H2O)8](Hdtp)(dtp)·H2O (Ln1, Ln3+ = La3+-Nd3+, Sm3+-Lu3+) were synthesized and characterized using single crystal X-ray diffraction and spectroscopic methods. Bond length analysis of VIIICm(III)-OH2 (where VIII refers to the coordination number) was compared to VIIILn(III)-OH2 (Ln3+ = Nd3+ and Sm3+), indicating similar VIIIM(III)-OH2 bond lengths because of their similar eight-coordinate ionic radii of these VIIIM(III) cations. Owing to the reduced coordination number, the VIIICm(III)-OH2 bond lengths were shorter than previously reported IXCm(III)-OH2 bonds in [Cm(H2O)9](CF3SO3)3. The octa-aquo complexes were also characterized by solid-state UV-vis-NIR spectroscopy in addition to variable-temperature and variable-pressure photoluminescence. Variable-pressure absorption spectra of Cm1 were compared with Ln1 and show that the Cm(III) f → f transitions have a stronger dependence on pressure than that observed in Ln1 (Ln3+ = Nd3+ and Sm3+). The experimental and computational analyses reveal that the monotonic decrease in the computed energy difference between the ground state and the first excited state corresponds to the observed red shift of the photoluminescence peak. This is accompanied by a gradual reduction in the average Cm(III)-OH2 bond length and a delocalization of spin densities, alongside an intensified interaction involving the 5f orbitals under increasing pressure. These changes accommodate the new geometry and collectively modify the energy landscape, resulting in peak broadening and quenching.

Iron(III) edta-accelerated growth of gold/silver core/shell nanoparticles for wide-range colorimetric detection of hydrogen peroxide

As a naturally occurring reducing and oxidizing agent, hydrogen peroxide (H2O2) has a role in several biotic and abiotic processes. Hence, the onsite, precise, and rapid determination of H2O2 is crucial. Herein, we propose a method for colorimetric detection of H2O2 on the basis of hindered formation of gold/silver core/shell nanoparticles. We used ascorbic acid (AA) as the electron donor to reduce silver ions (Ag+) to be shelled around gold nanoparticles and iron(III) edta as an accelerator reactant. Upon reduction of Ag+, owing to the formation of core/shell nanoparticles, the color of the system changes from pink to yellow/orange in the spherical nanoparticles and from pink to purple/blue/green/yellow/orange in the nanorods. The nanorods distinguished color in a rainbow manner for higher concentrations of H2O2, and spherical nanoparticles were critical in the sensitive detection of lower concentrations of H2O2. H2O2 scavenges AA electrons and therefore inhibits core/shell formation and, consequently, restrains the system’s spectral shift and color change. This characteristic was exploited to measure different concentrations of H2O2. Under well-optimized conditions, various concentrations of H2O2 ranging from 1.0 to 50 µΜ have shown an acceptable linear relationship with different colors and, with a limit of detection (LOD) of 230 nM. Furthermore, various real samples were examined to confirm the practicality of our developed probe.

Multivalent-effect immobilization of reduced-dimensional perovskites for efficient and spectrally stable deep-blue light-emitting diodes.

Despite substantial advances in green and red metal halide perovskite light-emitting diodes (PeLEDs), blue PeLEDs, particularly deep-blue ones (defined as Commission International de l'Eclairage y coordinate (CIEy) less than 0.06) that meet the latest Rec. 2020 colour gamut standard, lag dramatically behind owing to a severe phase segregation-induced electroluminescent spectral shift and low exciton utilization in broadened bandgap perovskite emitters. Here we propose a multivalent immobilization strategy to realize high-efficiency and spectrally stable deep-blue PeLEDs by introducing a polyfluorinated oxygen-containing molecule. Systematic experiments and extensive 5,000 fs ab initio molecular dynamics simulations reveal that a crucial role of the multivalent effect stemming from three kinds of interaction of hydrogen bond (F···H-N), ionic bond (F-Pb) and coordination bond (C=O:Pb) with perovskite is to synergistically stabilize the perovskite phase and enhance exciton radiative recombination. The resultant exciton concentration and exciton recombination rate of the deep-blue perovskite emitter are increased by factors of 1.66 and 1.64, respectively. In this context, our target PeLEDs demonstrate a peak external quantum efficiency of up to 15.36% at a deep-blue emission wavelength of 459 nm and a half-lifetime of 144 min at a constant current density of 0.45 mA cm-2. Moreover, the deep-blue PeLEDs maintain a constant spectrum peak with CIE chromaticity coordinates of (0.136, 0.051) under a steady driving current for 60 min.

Molecular and Electronic Structure and Properties ofthe Single Benzene-Based Fluorophores ContainingGuanidine Subunit.

The Gibbs energies of protonation (ΔGp) and the basic photophysical properties for single-benzene fluorophores (SBFs) containing guanidine and/or amino subunits and the changes that occur upon protonation were modeled by the TDDFT approach. The calculated ΔGp energies for amino SBFs in the S1 state range from 985 to 1100 kJ mol-1 which are below the values for guanidines. The protonation of the guanidine-SBFs induces a hypsochromic shift of the absorption and the emission maxima with the Stokes shift of > 100 nm in both cases. Isomerization through the ESIPT process is less probable than in amino-SBFs due to the unfavorable thermodynamics. Still, if it occurs, it leads to a strong red shift of the emission by > 150 nm. Aromaticity indices point to strong antiaromatic character of the examined guanidino-SBFs in the FC region which decreases upon geometrical relaxation and ESIPT. The excited state proton transfer occurs in guanidine-SBF/phenol complexes in the S1 state, stabilizing CT states and fluorescence quenching.

Catalytic-assisted remediation and phytotoxicity evaluations of organic pollutants in the presence of metal-doped Bi2O3-based NPs catalyst.

The chemical co-precipitation method was used to synthesize a variety of pure Bi2O3 and substituted Bi2-2xCoxCdxO3 NPs (x=0.0-0.8) and doping influences were evaluated based on the optical, photocatalytic, morphological, and structural characteristics. Powder X-ray diffraction (PXRD), scanning electron microscope (SEM), Energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), and UV-visible techniques were used to explore the characteristics of the synthesized Bi2O3-based NPs. XRD measurements confirmed the monoclinic structure and a P21/c space group, whereas the particle size was between 22 and 41nm. The SEM analysis gives the morphology of the synthesized NPs that were diverse and agglomerated platelets, whereas the EDX measurements provide the presence of Co and Cd in Bi2-2xCoxCdxO3 NPs. Additionally, FTIR investigations confirmed the existence of functional groups in Bi2-2xCoxCdxO3 NPs. The ultraviolet-visible absorbance region displaying a considerable red shift allowed for tuning of the band gap from 2.64 to 2.37eV. By analyzing the degradation of Reactive Black 5 (RB-5) dye in the presence of sunlight, pure Bi2O3 NPs showed 65.04% whereas the substituted Bi2-2xCoxCdxO3 NPs demonstrated enhanced photodegradation (86.40%) in 105min. For the degradation of RB-5 dye, the effects of catalyst dosage, dye concentration, and pH variations were studied as well. The phytotoxicity experiment was also performed by comparing the germination of Triticum aestivum seeds in treated and untreated RB-5 dye. In the untreated dye solution, seed germination was 50% inhibited, and in the treated dye solution, germination was observed to be 80%. Additionally, recycling investigations were used to confirm the stability of these fabricated nanoparticles, and the results showed that nanomaterials exhibited significant stability and reusability. Co and Cd-doped Bi2O3 NPs are promising solar-active photocatalysts for dye removal from wastewater applications because of their improved photocatalytic activity and narrow bandgap.

Spectroscopic (FT-IR and FT-Raman) and quantum chemical study on monomer and dimer of benznidazole from DFT and molecular docking approaches.

This work presents the quantum chemical calculations of the monomer and dimer of benznidazole using density functional theory (DFT) at the B3LYP/6-311++G(d,2p) level of theory. A one-dimensional potential energy surface scan was carried out across flexible bonds to find the minimum energy structure. The structure with minimum energy was taken as a monomer and dimer is constructed based on intermolecular hydrogen bonding N-H…O. The vibrational analysis was conducted by comparing the calculated FT-IR and FT-Raman spectra of the monomer and dimer with the experimental ones. The red shift in the spectra of amide and carbonyl functional groups indicates their involvement in intermolecular hydrogen bonding in crystal packing, while the other peaks showed good agreement with the experimental result. The intra- and intermolecular interactions in the monomer and dimer were analyzed using various tools. The steric effects and van der Waals forces in the dimer were found to be more effective than the monomer. The dimer in the gaseous medium was found to have a lower Frontier molecular orbital energy (ΔEL-H) value than the monomer, suggesting that it is more reactive in a gaseous medium. The ELF value for hydrogen in monomer and dimer around the ring was found to be more which confirms that the electrons in these regions are more localized. The negative value of the overlap population density of states (OPDOS) both in monomer and dimer indicate that there are anti-bonding orbitals between the acetamide and the benzyl groups of the compound. The drug potential of benznidazole was evaluated by molecular docking with carbonic anhydrase XII, which shows the highest binding affinity of (-8.3kcal/mol) with 6YH8, indicating that benznidazole is its potent inhibitor.

Raman and DFT study of non-covalent interactions in liquid benzophenone and its solutions

Analysis of intermolecular interactions in liquid benzophenone and its solutions in acetone and acetic acid by Raman spectroscopy and quantum-chemical simulation is presented. The results of the experiment show that in binary solutions of benzophenone, a red shift was observed for the C ˭ O stretching band, and a blue shift was observed for the C–H stretching and breathing bands. Such shifts were predicted to occur due to weak (non-classical) hydrogen bonds of C–H⋅⋅⋅O ˭ C type between benzophenone and solvent molecules. The nature and strength of solute-solvent interactions are discussed. The electron density distribution in benzophenone and its complexes with acetone and acetic acid molecules was visualized using the molecular electrostatic potential surface. The electronic properties of the molecular complexes were characterized using the frontier molecular orbitals and localization functions.

Near-field and far-field competitive couplings between plasmonic nanodisk array and nanoparticles for rapid and facile heparin assay.

Plasmonic biosensors hold an enticing prospect for drug testing and disease diagnostics as they have demonstrated impressive superiority in ultrasensitive and label-free detection. In this paper, we demonstrate a plasmonic sensing strategy for the heparin assay by leveraging near-field and far-field competitive couplings between gold (Au) nanoparticles (NPs) and nanodisk (ND) array. Specifically, the near-field coupling of the ND array and Au NPs binding to its surface results in a spectral redshift. Meanwhile, the far-field coupling of dispersed Au NPs in mixed solution and ND array induces a spectral blueshift. As a result, heparin concentration-dependent near-field and far-field competitive couplings determine the direction and amount of the spectral shift. Compared with existing detection technologies, this sensing strategy also presents a balance point, enabling rapid assessment of heparin dosage safety. Additionally, an exceptionally wide dynamic range of 10-4μg/mL to 103μg/mL, a low detection limit of 29pg/mL, and excellent selectivity are demonstrated. The analysis of heparin in serum further underscores this assay approach's potential for advancing disease diagnosis and therapeutic monitoring at the point of care.

Green synthesis of gold nano-particles using Madhuca indica flower extract and their anticancer activity on head and neck cancer: Characterization and mechanistic study.

Complete eradication of aggressive head and neck squamous cell carcinoma (HNSCC) still remains a major challenging problem due to numerous resistance properties of cancer stem cells (CSC) which is crucially responsible for tumor recurrence and metastasis. This challenge causes a high demand for the emergence of novel targeted treatment modalities for improved therapeutic efficacies. Phytochemicals derived from plants proves to be a wide reservoir of important drug candidates which have the potential to impede multiple aspects of malignant growth and progression. In the present study, we aimed to synthesize gold nanoparticles in a rapid and cost-effective manner by utilizing Madhuca indica flower extract and to evaluate its anticancer efficacy on head and neck cancer model via targeting cancer stemness and EMT. The phytochemicals present in the Madhuca indica flower extract acted as an effective reducing agent helping in the green synthesis of gold nanoparticles. The generated AuNPs were characterized by UV-Vis spectroscopy, XRD, FTIR, TEM, FE-SEM, DLS, EDX. Anti cancer potential of synthesized AuNPs were evaluated by in vitro and ex vivo HNSCC model. In vivo toxicity was assessed in Swiss albino mice model. The gold nanoparticles were characterized using UV-Vis spectroscopy which revealed unique wavelength maxima at 550nm and its crystalline nature was confirmed by XRD. AuNPs were observed to be spherical in shape with the mean diameter of 20.34±4.36nm and zeta potential of nearly -50mV. The FTIR spectral shift indicated the incorporation of various functional groups. MI-AuNP depicted strong anticancer attributes against HNSCC cell lines SCC154 and FaDu through significant inhibition of cancer stemness and EMT as evident from decreased tumor sphere forming efficiency and CD44+/CD24- subpopulation along with dose dependent downregulated expression of relevant CSC markers and EMT markers both in vitro and ex vivo HNSCC model. Additionally, no evidence of in vivo toxicity has been observed with MI-AuNP administration. In conclusion, this study reported for the first time that the MI-AuNP synthesized by novel green chemistry can efficiently prevent the self-renewal capability of HNSCC by targeting Cancer stemness. The scientific significance of this study lies in the fact that MI-AuNP might be a novel and potential therapeutic candidate against aggressive and metastatic HNSCC. The findings in this study unravels the way for developing a novel therapeutic candidate against aggressive and metastatic HNSCC with a much higher prognostic potential and significantly reduced off target toxicity.

Computational Investigation of Pristine, Al-, and Ga-Doped Zn12O12 nanoclusters as Detection Platforms for Methadone in gas and solvent phases

Computational Investigation of Pristine, Al-, and Ga-Doped Zn12O12 nanoclusters as Detection Platforms for Methadone in gas and solvent phases

Biogenic Silver Nanoparticles for the Estimation of Lead in Chocolates

Background: This study aimed to demonstrate the practical and sensitive lead detection using biogenic silver nanoparticles in dark chocolate samples and silver nitrate was reduced using Syzygium cumini aqueous seed extract as a reducing agent to produce nanoparticles. The obtained NPs were characterized via spectrometry and scanning electron microscopy. Method: Silver nitrate was reduced using Syzygium cumini aqueous seed extract as a reducing agent to produce nanoparticles. The obtained NPs were characterized via spectrometry and scanning electron microscopy. The formation of NPs was confirmed by a shift in lambda max to 430 nm and the observation of 2 nm-sized particles in SEM. Data on change in lambda max as a function of time must be shown in a figure. Silver nanoparticles mixed with lead induce a red shift from the original 430 nm to 434 nm absorption maximum, confirming the efficiency of silver nanoparticles in finding a lead. Result: We evaluated that the limit of detection (LOD) was to be 0.8715 μg/mL, and the limit of quantification (LOQ) was found to be 150 μg/ mL. Conclusion: The prepared biogenic silver nanoparticles have been used to detect lead in spiked diluted chocolates.

RGO‐Modified ZnO‐TiO2 Nanohybrids as Promising Antibacterial Agents for Biomedical Applications

AbstractThis study explores the synergistic antibacterial activity of ZnO nanorods (NRs) decorated with TiO₂ nanoparticles (NPs) and reduced graphene oxide nanosheets (rGO NSs). ZnO NRs and binary ZnO‐TiO₂ nanocomposites (ZT NCs) with varying TiO₂ content were synthesized using an in situ sol–gel method and subsequently modified with different amounts of rGO NSs. The nanocomposites were characterized using advanced techniques to assess their structure and antibacterial performance. X‐ray diffraction (XRD) confirmed the dominance of the hexagonal wurtzite ZnO structure, while Fourier transform infrared spectroscopy (FT‐IR) confirmed interconnectivity. A slight red shift in UV–vis diffuse reflectance spectra indicated changes in optical properties, and BET analysis showed an increase in surface area and pore volume due to rGO incorporation. The ternary ZT‐rGO (ZTR) NCs, particularly ZTR 4 (with 4 wt% rGO), exhibited significant antibacterial, antifungal, and antioxidant properties. ZTR 4 showed enhanced efficacy against both Gram‐positive (Staphylococcus aureus, Bacillus cereus) and Gram‐negative bacteria (Escherichia coli, Pseudomonas aeruginosa), as well as Candida albicans. The results highlight the synergistic effects of ZTR NCs, making them promising candidates for applications in biomedical and environmental fields as effective antibacterial agents.