Characteristic Surface Plasmon Resonance Research Articles

Localized surface plasmon resonance characteristics of gold dimeric nanobipyramids

Dimer is a new type of nanostructure that has attracted much attention due to its ability to achieve more significant field strength enhancement effects through the interaction of two nanoparticles than monomers. This paper applies the dimer structure to gold nanobipyramids particles with unique tip structures. The localized surface plasmon resonance properties of the gold dimeric nanobipyramids are simulated using the finite difference time domain method. The results show that the gold dimeric nanobipyramids achieves several times higher field enhancement in the nanogap compared to the gold monomer nanobipyramids. At the same time, under the same conditions, its electric field intensity is significantly higher than that of the gold dimeric nanospheres and gold dimeric nanorods. Furthermore, by varying the gap, sharpness, and surrounding medium, the changes in the LSPR effects of the gold dimeric nanobipyramids under different conditions were calculated. The research shows that by tuning the structure, morphology, and surrounding medium of the dimeric nanobipyramids, higher extinction intensity, more intensity field enhancement, and greater sensitivity can be achieved, offering significant application prospects in various optoelectronic device fields. This work has significant reference value for studying the localized surface plasmon resonance characteristics of dimeric metal nanoparticles and their related applications.

Phytochemical Analysis, Isolation, and Characterization of Gentiopicroside from Gentiana kurroo and Cytotoxicity of Biosynthesized Silver Nanoparticles Against HeLa Cells.

Gentiana kurroo Royle, a critically endangered Himalayan herb, is valued in treating leucoderma, syphilis, bronchial asthma, hepatitis, etc. The current investigation performed quantitative and qualitative phytochemical analysis of G. kurroo root extracts prepared in chloroform, methanol, and ethyl acetate. The phenolic and flavonoid contents were the highest in methanol and chloroform extract, respectively. Several pharmacologically important compounds were identified through gas chromatography-mass spectrometry. Antioxidant analysis revealed methanolic extract to be the most efficient scavenger of 2,2-diphenyl-1-picrylhydrazyl (IC50 = 114µgmL-1), hydrogen peroxide (IC50 = 109.9µgmL-1), and superoxide (IC50 = 74.63µgmL-1) radicals. Gentiopicroside was isolated from the methanolic root extract through silica-gel column-chromatography, and the characterization of concentrated fractions was achieved employing various analytical techniques. Pertaining to silver nanoparticle (GkAgNPs) synthesis, different physicochemical parameters were optimized and it was observed that root extract treated with silver-nitrate (0.5mM) at 60°C and incubated in dark for at least 120min after initial color change, yielded GkAgNPs optimally. GkAgNPs were anisotropic and polydisperse and exhibited characteristic surface plasmon resonance (424nm), crystalline face-centered cubic geometry, size (50-300nm), and zeta-potential (- 16.3mV). FT-IR spectra indicated the involvement of phenols and flavonoids in AgNPs synthesis. GkAgNPs were evidenced as strongly cytotoxic (IC50 = 1.964µgmL-1) against HeLa cells and also showed deformed cellular morphology, a significant reduction in viable cell counts and colony-forming efficiency (4.08%). The findings suggest potential applications in drug development for treating serious human diseases. To the best of our knowledge, this study represents the first report on the isolation of gentiopicroside, the bio-fabrication of GkAgNPs using G.kurroo root extract, and their strong bioefficacy against HeLa cells.

Prominence of copper in AuCu alloy towards enhance surface plasmon resonance-driven water oxidation

To fully harness the potential of surface plasmon resonance (SPR) in augmenting photocatalytic water oxidation, a comprehensive exploration of structure-activity relationship of metal nanoparticles is essential. This work presents a wrap-bake-peel (WBP) strategy designed to stabilize AuCu/TiO2 nanostructures while preserving SPR absorption and refining the metal-semiconductor interfaces. Through strategically incorporating trace Cu into Au (Cu/Au = 0.06), we achieved a 2.6-fold enhancement of SPR-induced oxygen evolution reaction (OER) performance compared to pristine Au/TiO2. This enhancement is due to the synergistic effect of SPR and a well-defined Schottky barrier, which improves plasmonic hot carrier charge separation, as verified by detailed spectroscopic analyses. The incorporation of copper plays a critical role, acting as an electron shuttle that facilitates the transfer of hot electrons from photoexcited gold to the AuCu NP surface, thereby reducing recombination. This process, driven by SPR-induced hot electrons from Au, also extends electron-phonon (τ0e-ph), interactions by 138 %, significantly prolonging hot carrier lifetimes. Mechanistic insights reveal that d-band onset potentials (Ed-AuCu∼-0.9 V/ Ed-Au∼-1.2 V) and increased hot hole d-band occupancy in AuCu further enhance the overall SPR-induced water oxidation performance. Simulated electron distributions and quantum confinement in AuCu vs. Au critically dictate SPR characteristics, enabling precise modulation of plasmonic responses. These findings underscore the crucial role of Cu in fine-tuning the properties of plasmonic photocatalysts, demonstrating a significant advancement in the rational design of efficient solar-to-fuel conversion systems.

Anisotropic fluorescence surface quenching of quantum dot-in-rods on silver nanopatterned film

Semiconductor quantum dot-in-rods (QDIRs) have served in the broad applications such as luminescent applications, sensor technology, quantum information processing, due to their polarized emission and polarized absorption characteristics. The localized surface plasmon resonance (LSPR) characteristics of the noble metal nanostructures can regulate the fluorescence intensity by controlling the radiation and non-radiation channels of fluorescent substances. However, the reports on the fluorescence surface quenching of QDIRs by plasmonic nanoparticles (NPs) are very rare. Herein, we propose a new method to realize QDIRs orientation, as well as the fluorescence intensity can be regulated. The effect of Ag nanopatterned film on the fluorescence surface quenching of QDIRs is discussed from both theoretical and experimental perspectives. Generally, the direct combination of Ag nanopatterned film and QDIRs results in 75% fluorescence surface quenching. Through FDTD simulation, we further analyzed the modulation of fluorescence intensity of the dipole source by the Ag nanopatterned film. This work will be useful for the development of QDIRs in the future.

Characterization of Copper Nanoparticles synthesized Using the Leaf Extracts of Lawsonia inermis, Eucalyptus globulus, Psidium guajava, and Azadirachta indica

Green synthesis of nanoparticles using plant extracts is a sustainable, eco-friendly, non-toxic, and cost-efficient approach. In this study, copper nanoparticles (CuNPs) were synthesized using the mehandi Lawsonia inermis, nilgiri Eucalyptus globulus, guava Psidium guajava, or neem Azadirachta indica leaf extracts and 1mM CuSO4.5H2O salt solution in a ratio of 1:3 at 800C temperature and characterized using UV-Visible spectroscopy, Fourier Transform Infrared spectroscopy, and Field Emission Scanning Electron Microscopy analysis. All the CuNPs showed colour change with characteristic surface plasmon resonance bands. The plasmon resonance bands of L. inermis, P. guajava, and A. indica CuNPs peaked at 300nm while those of E. globulus CuNPs peaked at 400nm. The CuNPs synthesized from L. inermis, E. globulus, and P. guajava leaf extracts exhibited brown colour while those synthesized from A. indica leaf extracts showed green colour. Eleven bands were present in L. inermis and A. indica CuNPs in the range of 538.61-3649.06cm-1 and 3867.26-519.02cm-1, respectively, while ten were in the E. globulus and P. guajava CuNPs in the range of 407.25-3326.78cm-1 and 3325.93-407.07cm-1, respectively. The L. inermis, E. globulus, and A. indica CuNPs were spherical, except P. guajava CuNPs which were flaky in shape. The particle size of L. inermis CuNPs was found in the range of 8.20 to 15.94nm; E. globulus CuNPs in the range of 7.52 to 67.47nm; P. guajava CuNPs in the range of 18.90 to 73.80nm and A. indica CuNPs in the range of 9.86 to 22.05nm.

Characterization of Zinc Nanoparticles Synthesized Using the Mushroom, Pleurotus sajor-caju

Fungi including mushrooms contain various enzymes and biomolecules, making them an effective agent for synthesizing various nanoparticles. This study aimed to synthesize and characterize zinc nanoparticles using the zinc sulphate salt at the concentration of 1mM and the mushroom Pleurotus sajor-caju. The P. sajor-caju synthesized zinc nanoparticles were characterized using UV-Visible spectral analysis, Field Emission Scanning Electron Microscopy, and Fourier Transform Infrared Spectroscopy. They did not change the color and showed a characteristic surface plasmon resonance band peaking at 300nm. They were spherical and the particle size was found in the range of 7.29 nm to 13.27 nm. They showed ten bands at different stretching with wave numbers ranging between 675.17cm-1 and 3675.56cm-1. The presence of advantageous features in the zinc nanoparticles synthesized from P. sajor-caju revealed the usefulness of the synthesis of other metal nanoparticles from P. sajor-caju.

Optical fiber-coupled Kretschmann SPR sensor with re-attachable gold nano-thin film sensing chip.

We designed and demonstrated a portable and reusable surface plasmon resonance (SPR) sensor based on an optical fiber-coupled Kretschmann configuration with a variable detection limit enabled by the re-attachable gold nano-thin film. The prism angle of SPR has been optimized to 63.5 degrees to enable the SPR sensor to operate in the near-infrared band. We highlight the effects of the chromium to gold film thickness ratio and the prism angle on the SPR characteristics to improve sensitivity. Both simulations and experimental results reveal that the narrowest FWHM and deepest amplitude of the SPR curve were achieved when the chromium to gold film thickness ratio was set to 2 nm/40 nm. Furthermore, the refractive index (RI) sensitivity of the sensor was simulated within the RI detection range of 1.3235-1.3290, and with the optimized SPR sensor, we obtained a record high RI sensitivity of 34,888 nm/RIU. The capability to detect variations in saline and sucrose concentration in aqueous form has been experimentally demonstrated, revealing a sensitivity of 455 nm/M and 3,056 nm/M over concentration ranges of 0.10 to 0.55 M and 0.018 M to 0.053 M, respectively. The results show that the proposed optical fiber-coupled SPR sensor with an optimized sensing chip offers high sensitivity and is promising for a broad range of applications, including medical diagnostics, agriculture, food safety, and environmental monitoring. The sensor's advantages include miniaturization and flexibility, highlighting its potential for broad and versatile use.

Absorption of electromagnetic waves by cylindrical surface plasmon resonance

Abstract The absorption characteristics of cylindrical surface plasmon resonance (CSPR) have been studied. We demonstrated that a single plasma column with CSPRs can achieve high absorptivity at the plasmon frequency. We also studied the effects of plasma density and collision frequency on the absorptivity. As both of them increase, the corresponding absorptivity tends to increase first and then decrease, but with different reasons. Such manifestation is explained by analyzing transmission and reflection spectra in both cases, as well as magnetic field distribution patterns at the frequency of plasmon. On the one hand, the increase in plasma density leads to the enhancement of plasmons, improving transmittance; On the other hand, the increase in collision frequency leads to a weakening of plasmons and an increase in reflectivity. Finally, we investigated the absorption characteristics of plasmons in the plasma photonic crystals (PPCs) structure and overcame the absorption attenuation caused by the increase in plasma density by increasing the number of plasma columns. Meanwhile, the absorption generated by surface plasmon resonance is not affected by the lattice constant of PPCs. The research has shown that efficient absorption can be achieved using CSPR, resulting in extremely high absorptivity when using fewer plasma columns. Finally, we verified the absorption ability of CSPRs through experiments.

Electrochemical immunosensor based on gold nanoparticles for the detection of creatine kinase as a cardiac marker

This study presents the development of an electrochemical immunosensor utilizing gold nanoparticles for the detection of creatine kinase (CK), a crucial cardiac marker. Gold nanoparticles with an average diameter of 18.3 ± 2.1 nm were synthesized and characterized, exhibiting a characteristic surface plasmon resonance peak at 520 nm. The construction of the immunosensor was observed through cyclic voltammetry and electrochemical impedance spectroscopy, showing notable alterations in electron transfer rates during each step of the assembly process. Optimal performance was achieved at pH 7.4, with an antibody concentration of 100 μg/mL and an incubation time of 45 minutes. The sensor demonstrated a sensitivity of 152.6 Ω/(ng/mL) and maintained its response in the presence of common interfering substances, with maximum signal deviation of 7.2 %. Testing with spiked human serum samples yielded recovery rates between 96.5 % and 103.8 %. Comparison with ELISA using clinical samples further validated the sensor's accuracy. This AuNP-based immunosensor offers a promising platform for rapid and sensitive CK detection in cardiac health assessment.

Eco-friendly synthesis of bioactive silver nanoparticles from black roasted gram (Cicer arietinum) for biomedical applications

Green synthesis leverages biological resources such as plant extracts to produce cost-effectively and environmentally friendly NPs. In our study, silver nanoparticles (AgNPs) are biosynthesized using blank roasted grams (Cicer arietinum) as reducing agents. CA-AgNPs were characterized by a characteristic surface plasmon resonance (SPR) peak at 224 nm in the UV–Vis spectrum. FTIR analysis revealed functional groups with O–H stretching at 3410 cm−1, C–H stretching at 2922 cm−1, and C=O stretching at 1635 cm−1. XRD patterns exhibited sharp peaks at 33.2°, 38.4°, 55.7°, and 66.6°, confirming high crystallinity. Morphological analysis through FESEM indicated spherical CA-AgNPs averaging 500 nm in size, with EDS revealing Ag at 97.51% by weight. Antimicrobial assays showed zones of inhibition of 14 mm against Candida albicans, 18 mm against Escherichia coli., and 12 mm against Propionibacterium acnes. The total phenolic content of CA-AgNPs was 26.17 ± 13.54 mg GAE/g, significantly higher than the 11.85 ± 9.57 mg GAE/g in CA extract. The ABTS assay confirmed the antioxidant potential with a lower IC50 value of 1.73 ± 0.41 µg/mL, indicating enhanced radical scavenging activity. Anti-melanogenesis was validated through tyrosinase, showing inhibition rates of 97.97% at the highest concentrations. The anti-inflammatory was evaluated by western blot, which showed decreased expression of iNOS and COX-2. This study demonstrates the green synthesis of CA-AgNPs and its potential biomedical applications. The results of this study demonstrate that biosynthesized CA-AgNPs have key biological applications.

Green synthesis of silver nanoparticles using Lepidium sativum seed mucilage as a bioreductant/capping agent for efficient antibacterial and photocatalytic activities

Contamination of aquatic resources with organic dyes and pathogenic bacteria ranks among the most serious threats to human survival and the environment. The current work investigated L. sativum seed mucilage as a reducing and capping agent for Ag NPs. From UV–vis spectroscopy, the characteristic surface plasmon resonance peak and the band gap energy of as-fabricated NPs were 440 nm and 2.07 eV, respectively. SEM revealed irregular-shaped NPs with an average diameter of 73.85 nm and EDX disclosed Ag along with C, O, and Si from mucilage’s biomolecules. The antibacterial and antibiofilm results showed higher inhibitory effects against the Gram-positive (B. cereus) than the Gram-negative (E. coli, and E. aerogenes) bacteria. The biosynthesized NPs were impressive in degrading methylene blue (MB, 89.45 %) and methyl orange (MO, 84.78 %) under optimized conditions viz., dye solution (20 ppm), photocatalyst dose (5 mg), light intensity (UV index of 10 +), and irradiation time (120 min). The kinetic data strongly supported the pseudo-first order model with maximum adsorption capacities of 787.40 and 724.64 mg/g for MB and MO, respectively as determined through the Langmuir isotherm model. The photocatalyst exhibited sufficient stability even after six repeated cycles, highlighting its suitability for industrial and commercial applications.

Antibacterial, antioxidant, and anti-giardia properties of the essential oil, hydroalcoholic extract, and green synthesis of the silver nanoparticles of Salvia mirzayanii plant

In this study, an environmentally-friendly, simple, and low-cost approach was developed for the production of silver nanoparticles (Ag NPs) accelerated by Salvia mirzayanii plant. The identification process involved ultraviolet-visible (UV-Vis) spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). The UV–Vis spectrum exhibited a peak at 450 nm which is a characteristic surface plasmon resonance of Ag NPs. The XRD and EDS analyses confirmed the crystalline nature and the presence of silver element, while the SEM analysis displayed the production of almost spherical nanoparticles. The FTIR spectrum exhibited that the Ag NPs were functionalized with biomolecules found in the extract, which are involved in the production and stabilization of the NPs. The antibacterial activity of the essential oil, the hydroalcoholic extract and Ag NPs was examined against antibiotic-resistant bacteria, Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). The anti-Giardia activity was tested on Giardia lamblia cysts at different time intervals. The results exhibited that the MIC values for essential oil, hydroalcoholic extract and Ag NPs against S. aureus were 1.65 µL/mL, 75 mg/mL, and 0.125 mg/mL respectively. The MBC was attained 6.25 µL/mL, 300 mg/mL, and 0.25 mg/mL, for essential oil, hydroalcoholic extract and Ag NPs, respectively. The MIC values for essential oil, hydroalcoholic extract and NPs against E. coli were 3.12 µL/mL, 150 mg/mL, and 0.06 mg/mL, respectively. The MBC was determined to be 50 µL/mL, 300 mg/mL, and 0.25 mg/mL for essential oil, hydroalcoholic extract and Ag NPs, respectively. In addition, the antioxidant activity was determined using the ferric reducing antioxidant power (FRAP) test. The results indicated that the essential oil of this plant exhibited the highest antibacterial and anti-giardial properties, whereas its extract demonstrated the strongest antioxidant properties.

Synthesis of Palladium Nanomaterials Using Plant Leaf Extract and their Enhanced Photocatalytic Activities against Organic Dyes

Aims and Objectives: This study aimed to carry out the green synthesis of palladium nanoparticles (Pd NPs) using the aqueous leaves extract of Eclipta alba. The appearance of a characteristic surface plasmon resonance peak at 410 nm confirmed the synthesis of Pd NPs. Method: The average particle sizes of 13 nm were observed by using the leaf concentrations of 10 mL with a certain amount of PdCl2 (0.001 M) at 25 ̊ C. The Pd NPs, as synthesized under the optimized conditions (10 mL extract + 60 ̊ C + 0.001 M PdCl2), were spherical in shape, small in size, and uniformly distributed, as depicted by HR-TEM images. Results: FTIR, XRD, DLS, and zeta potential further confirmed the formation of Pd NPs. The Pd NPs synthesized at optimized conditions exhibited strong catalytic activity in dye Eosin yellow, Rose Bengal, Tartrazine, and Ponceau S degradation by discoloration of dyes in 3 hrs. The removal of all dyes by the Pd NPs was optimized by varying specific operating parameters, such as initial dye concentration, solution pH, irradiation time, and temperature. Conclusion: This high activity of Pd NPs may be due to their small size, high dispersion, and surface- capping phytochemicals. result: Bio-fabrication of metallic Pd NPs using different plant extracts compared to other reducing agents is more scalable, rapid, and cost-effective for generating bulk nanoparticles. The phytochemical principles, such as phytoconstituents, reduce the PdCl2 to Pd NPs and are implicated in the capping and stability of the nanoparticles. Hence, the leaves of Eclipta alba have different polyols and are well known. Apart from this, hydroxyl groups in phenolic compounds may participate in the bio-reduction of PdCl2. Such compounds can chelate metal ions to form their quinones form, which is an intermediate palladium complex. Then, stabilization of the intermediate form and reduction of Pd2+ to Pd0 occurred due to free electrons or nascent hydrogen produced during the bio-reduction reaction. Finally, Pd-NPs were prepared due to the collision of neighboring Pd0 atoms. These significant conjugations exist in the keto-enol system within the quinone form of the compound.

Characterization and toxicity evaluation of chitosan/ZnO nanocompoite as promising nano-biopolymer for treatment of synthetic wastewater

Nanotechnology advances wastewater treatment through the application of Nano entities that optimize contaminant removal and enhance water purification efficacy. In this study, ZnO nanoparticles (ZnO NPs) were synthesized using Klebsiella pneumoniae, subsequently, a chitosan/ZnO nanocomposite (CS/ZnO NC) was prepared for removing reactive black 5 (RB-5) dye from synthetic wastewater. The biosynthesized nanomaterials were characterized using UV–VIS, FTIR, XRD, SEM and TEM techniques. The UV–Vis absorbance peaks at 370 nm and 350 nm corresponded to the characteristic surface plasmon resonance of ZnO NPs and the CS/ZnO NC, respectively. Additionally, FTIR analysis identified the various functional groups associated with ZnO NPs and the CS/ZnO NC. XRD analysis revealed their crystallinity to be approximately 22.44 and 25.76, respectively. The SEM images of ZnO NPs and the CS/ZnO NC show hexagonal plate-like particles with sizes of 33.66 nm and 38.64 nm, respectively. Four concentrations of ZnO NPs and CS/ZnO NC (0.25, 0.5, 1, and 2 mg/mL) were evaluated for RB-5 degradation at three different levels (25, 50, and 100 mg/L). Statistical analysis showed that chitosan/ZnO NC achieved 95 % dye degradation, compared to 81 % degradation with the same amount of ZnO nanoparticles. Furthermore, a pot experiment was carried out to evaluate the phytotoxicity effects of treated wastewater on wheat (Triticum aestivum L.). Both ZnO NPs and CS/ZnO NC did not significantly affect the viability of epithelial retinal cell lines at concentrations up to 100 µg/mL, suggesting a safe cytotoxic profile within this dosage range. Overall, CS/ZnO NC proved effective for treating industrial wastewater, making it suitable for recycling in agricultural applications

Microwave-assisted green synthesis of silver nanoparticles using Mitragyna parvifolia bark extract and their biological activities: an economical and environment-friendly approach

ABSTRACT Nowadays, nanotechnology is extensively employed in the medical profession. In this study, we used the aqueous extract of the bark of Mitragyna parvifolia to synthesize silver nanoparticles (AgNPs) by microwave-assisted green synthesis. The synthesis of AgNPs was confirmed by visual color change to brown color and characteristic surface plasmon resonance peak at 432 nm. The hydrodynamic diameter of the AgNPs was 171.81 nm having a zeta potential of −24.14 mV; Fourier Transmission Infrared Spectroscopy confirmed the presence of different functional groups on the NP surface; Scanning Electron Microscope and High-Resolution Transmission Electron Microscopy indicated predominantly circular shape of nanoparticle; Selected Area Electron Diffraction and X-ray Diffraction analyses determined the crystalline structure of AgNPs. Energy-Dispersive X-ray indicated the elemental composition and formation of AgNPs. The AgNPs were screened at different concentrations for antioxidant activity, antimicrobial, and anticancer potential in breast cancer cells (MCF-7 and MDA-MB-231). The AgNPs exhibited remarkable antioxidant, antimicrobial, and anticancer activities. The sedative and antinociceptive activities were also tested on Swiss albino mice, which showed mild sedative and very potent antinociceptive activity. However, detailed mechanistic studies are warranted in the future for clinical application of the AgNPs as a biologically active agent as well as a carrier for drug delivery.

Unveiling the Influence of Line Shape of Surface Plasmon Resonances on Exciton–Plasmon Strong Coupling

AbstractStrong coupling between surface plasmon resonance (SPR) modes and excitons holds great potential for many chemical and physical applications. However, a clear understanding on how far‐field spectral characteristics of SPR (linewidths and intensity) affect the coupling strength remains unclear because these parameters are difficult to be individually tuned. These spectral characteristics are associated with the damping rate and field enhancement that depend on the morphology of the plasmonic nanostructure. In this work, the influence of the SPR line shape on exciton‐plasmon coupling is systematically investigated by delicately tuning the linewidths and resonance intensities of the plasmonic arrays. It is found that the SPR modes with narrow linewidths or large intensity are favorable for the exciton–plasmon system to achieve strong coupling. The obtained clear relationships between the SPR line shape and coupling strength provide guidance for the design and optimization of exciton‐plasmon coupling systems, favoring the highly efficient manipulation of exciton polaritons and enabling specific applications driven by strong coupling.

Plant Extract-Mediated Synthesis of Silver Nanoparticles and Their Anticancer Potentials

Five plant extracts (Ardisia argentea, Aegiceras corniculatum, Polycarpaea corymbosa, Maesa perlaria, and Schima wallichii) were utilized as reducing agents in the synthesis of silver nanoparticles (AgNPs) through a green route. As the reducing power and total content of phenolic compounds in the extract increased, the absorbance of the surface plasmon resonance of the resulting AgNPs also increased. The characteristic surface plasmon resonance was clearly observed at 400∼500 nm. The AgNPs were spherical, as shown by field emission transmission electron microscopy images, with an average size between 10.4±0.3 nm and 22.2±0.8 nm. The cytotoxicity in A549 (lung cancer) and HeLa (cervical cancer) cells increased in a dose-dependent manner. Specifically, at the highest dose, the AgNPs synthesized with the A. corniculatum extract exhibited the highest cytotoxicity and induced high levels of reactive oxygen species (ROS). Interestingly, it was observed that smaller AgNPs tended to generate higher levels of ROS. Cell death was clearly observed in the treatment with the AgNPs. A G2/M phase arrest occurred in cell cycle analysis, which induced cell death. The results obtained herein support the potential of natural product-mediated synthesis of AgNPs as a promising anticancer nanomedicine.

Development of a Synergistic Nanomaterial Scaffold Combining Silver Nanoparticles, Collagen, and Doxycycline for Enhanced Scar-Free Skin Regeneration.

Introduction The efficacy of wound-healing treatments can be significantly enhanced through innovative combination therapies. This research investigates the wound-healing properties of a combination therapy involving silver nanoparticles (AgNPs) synthesized using Delphinium denudatum (Dd), bovine tendon collagen (BTC), and the antibiotic doxycycline (DOX) in Wistar albino rats. Each component has known therapeutic benefits: AgNPs possess antimicrobial properties, BTC aids in tissue regeneration, and DOX is an effective antibiotic. The synergy between these components is hypothesized to enhance wound closure, reduce inflammation, and promote scar-free healing. Methods The synthesis of DdAgNPs was carried out using Dd. The presence of AgNPs was confirmed by ultraviolet-visible (UV-Vis) spectroscopy and high-resolution transmission electron microscopy (HRTEM). The study was conducted on Wistar albino rats following ethical guidelines for animal research. The rats were divided into different groups to receive various treatments: DdAgNPs alone, BTC alone, DOX alone, combinations of two components, and the triple combination of DdAgNPs: BTC: DOX. Wound closure rates, epithelialization, and collagen deposition were monitored and recorded over time. Tissue samples from the wound sites were collected for histological analysis. Hematoxylin and eosin (H&E) staining was used to evaluate epithelialization and overall tissue architecture. Collagen deposition was assessed using Masson's trichrome staining. Additionally, the expression of cyclooxygenase-2 (COX-2) was measured as an indicator of inflammation. Results UV-Vis spectroscopy provided the characteristic surface plasmon resonance peak indicative of AgNPs, while HRTEM revealed the morphology and size of the nanoparticles, showing spherical particles with an average size of 35±10.42 nm. The combination therapy of DdAgNPs: BTC: DOX significantly enhanced wound closure compared to individual and dual-component treatments. This was evidenced by faster epithelialization and increased collagen deposition. The histological analysis showed that the triple combination treatment resulted in more organized tissue architecture and denser collagen fibers. Furthermore, the treatment led to a marked decrease in COX-2 expression, indicating reduced inflammation and potential for lower scar formation. Conclusion The synergistic application of DdAgNPs, BTC, and DOX presents a promising strategy for advanced wound healing and tissue regeneration. The combination therapy not only accelerates wound closure but also enhances the quality of healing by promoting epithelialization and collagen deposition while reducing inflammation. These findings offer a potential pathway for developing effective, scar-free healing solutions, highlighting the benefits of integrating multiple therapeutic agents in wound care.

Biosynthesis of gold nanoparticles by fungi and its potential in SERS.

Surface enhanced Raman spectroscopy (SERS) by using gold nanoparticles (AuNPs) has gained relevance for the identification of biomolecules and some cancer cells. Searching for greener NPs synthesis alternatives, we evaluated the SERS properties of AuNPs produced by using different filamentous fungi. The AuNPs were synthesized utilizing the supernatant of Botrytis cinerea, Trichoderma atroviride, Trichoderma asperellum, Alternaria sp. and Ganoderma sessile. The AuNPs were characterized by ultraviolet-visible spectroscopy (UV-Vis) to identify its characteristic surface plasmon resonance, which was located at 545nm (B. cinerea), 550nm (T. atroviride), 540nm (T. asperellum), 530nm (Alternaria sp.), and 525nm (G. sessile). Morphology, size and crystal structure were characterized through transmission electron microscopy (TEM); colloidal stability was assessed by Z-potential measurements. We found that, under specific incubation conditions, it was possible to obtain AuNPs with spherical and quasi-spherical shapes, which mean size range depends on the fungal species supernatant with 92.9nm (B. cinerea), 24.7nm (T. atroviride), 16.4nm (T. asperellum), 9.5nm (Alternaria sp.), and 13.6nm (G. sessile). This, as it can be expected, has an effect on Raman amplification. A micro-Raman spectroscopy system operated at a wavelength of 532nm was used for the evaluation of the SERS features of the AuNPs. We chose methylene blue as our target molecule since it has been widely used for such a purpose in the literature. Our results show that AuNPs synthesized with the supernatant of T. atroviride, T. asperellum and Alternaria sp. produce the stronger SERS effect, with enhancement factor (EF) of 20.9, 28.8 and 35.46, respectively. These results are promising and could serve as the base line for the development of biosensors through a facile, simple, and low-cost green alternative.

Green and chemical synthesized zinc oxide nanoparticles: Evaluation of their anti-proliferative activity against breast cancer cell line – An in vitro and in silico approach

Zinc Oxide nanoparticles (ZnO NPs) were synthesized through both chemical and green approaches using wheat grass (WG) extract. Characterization techniques included Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM) with Energy-Dispersive X-ray Spectroscopy (EDX), Fourier-transform infrared Spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and Ultraviolet-visible (UV-Vis) spectroscopy. CS-ZnO NPs and WG-ZnO NPs exhibited characteristic surface plasmon resonance (SPR) peaks at 360 nm and 320 nm, respectively, with low polydispersity index (PDI) values indicating uniform nanoparticle dispersion. FTIR analysis revealed distinct functional groups on the ZnO NPs’ surface for stabilization. XPS confirmed atomic composition and oxidation state, while XRD confirmed their hexagonal wurtzite structure. SEM images revealed rod-shaped structures, supported by EDX analysis confirming ZnO NP formation through elemental content. The synthesized ZnO NPs demonstrated significant cytotoxicity against MDA-MB 231 breast cancer cells, causing changes in nuclear morphology, increased reactive oxygen species levels, and membrane damage. Wound healing assay highlighted their potential in inhibiting cancer metastasis. Molecular docking between WG compounds and breast cancer targets revealed that the enhanced efficacy of green-synthesized ZnO NPs could be attributed to covalent linkage of active molecules of WG onto the nanoparticle surface. Overall, ZnO NPs synthesized using the green method outperformed their chemically synthesized counterparts.