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The synthesis and characterization of Au nanoparticles produced from Punica granatum L. leaves (PGL) grown in Trabzon province of Turkey were investigated in this study. After the pomegranate leaves were collected, they were dried under suitable conditions and divided into small pieces, and Supercritical Fluid Extraction (SFE) was applied to obtain the extract. The SFE was performed at a pressure of 200 bar, 50 °C for a period of 2.5 h using ethanol modifier at 0.5 mL/min flow rate in this procedure. Twenty milliliters of 0.5 mM HAuCl4.3H2O solution was mixed in the microwave device with different volumes of the prepared aqueous solution (0.1 mL and 0.2 mL). After the mixture was exposed to microwaves for 1 to 30 min at a power of 90 W, Au nanoparticles were synthesized. Au nanoparticles produced utilizing green chemistry principles were characterized by UV–Vis, TEM, FTIR, XRD, and Zeta-sizer. The surface plasmon resonance absorption (SPR) spectra were measured using the UV–visible technique to determine the ideal conditions. The TEM images showed that the PGL-AuNPs had a mean size of 23.510 ± 7.009 nm, with sizes ranging from 14.188 to 42.508 nm, and a shape that was triangular, spherical, or elliptical. The reflection peaks appear at 38.21, 44.40, 64.61, and 77.59 corresponding to lattice planes (111), (200), (220), and (311), respectively. The average size of the synthesized gold nanoparticles is 23.24 nm. The Au nanoparticles have an average particle size of 50.76 ± 1101 nm in aqueous medium, a zeta potential of −14.8 ± 0.4 mV, and the polydispersity index for gold nanoparticles is 0.45 ± 0.011, indicating a moderately level of polydispersity. AuNP production was best achieved at 0.5 mM concentration in 0.1 mL pomegranate (P. granatum L.) leaves extract volume. The process utilized for producing the gold nanoparticles allowed for their stability for 2–2.5 months. [ABSTRACT FROM AUTHOR]

In this work, a high performance surface plasmon resonance (SPR) fiber sensor based on metallic elliptical nanohole and circular nanodisk binary array has been theoretically designed and investigated. The binary array structure is integrated on the end facet of optical fiber to excite SPR and generate three optical resonance dips in reflection spectra in the near-infrared region. The first resonance dip not only fits the characteristics of narrow linewidth, but also has the advantages of high peak-to-dip signal ratio and sensitivity. When the external environment changes in the refractive index (RI) range of 1.33 ~ 1.40, a high RI sensitivity of 669 nm/RIU, a narrow FWHM of 5.8 nm, and a high FOM value of 115.3 are yielded simultaneously for the first dip. Compared to unitary nanostructure arrays, the composite plasmonic structure of nanodisk and elliptical nanohole array demonstrated here can generate SPR modes with sharper spectral feature which is crucial to high sensitivity and precision detection technology. These features make our proposed plasmonic fiber tip sensor highly promising in terms of high-performance biosensing applications. [ABSTRACT FROM AUTHOR]

In this study, silver nanoparticles (Ag NPs) dispersed in deionized water (DW) are prepared using the Nd:YAG laser ablation method. Transmission electron microscopy (TEM) results were used to investigate the shape and particle size of Ag NPs. The spherical shape and size of about 30 nm are characterized. X-ray diffraction (XRD) analysis shows a good crystallinity of Ag NPs and distinguished peaks at 38° without any impurities. The optical properties of Ag NPs were studied by a UV–visible spectrophotometer, and the surface plasmon resonance was observed at an excitation wavelength of about 402 nm and a direct band gap of about 2.25 eV. The results of the inhibitory activity against Lactobacillus and Streptococcus mutans bacteria indicated areas of high inhibition. The highest inhibition zone was 19 mm at the stock concentration. The anticancer properties of Ag NPs were studied with multi-concentration; the small particle size of Ag NPs led to the killing of about 70% of the MCF-7 line; and the inhibitory concentration (IC50) of Ag NPs was about 93.55 µg/mL−1. [ABSTRACT FROM AUTHOR]

Throughout history, societies have harnessed renewable energy sources driven by technological advancements and external factors, resulting in the emergence of hydropower, wind turbines, and solar PV, often bolstered by supportive policies and agreements. In the current research, the cylinder-inspired resonator solar absorber (CIRSA) structure has been introduced in optical science. This innovative design, functioning at the nanoscale, achieves exceptional wideband absorption from 200 to 700 nm, a challenge given Earth's limited wavelength spectrum. Impressively, it attains a 98.71% solar energy absorptance within this range, with notable peaks at 490 nm (98.99%) and 500 nm (98.71%) in the solar thermal wavelength band, maintaining high absorption across angles from 0 to 80° for both TE and TM polarizations. Moreover, this cylinder-inspired solar thermal energy absorber effectively minimizes solar energy losses and ensures a high Air Mass Index (AM 1.5), although a significant reduction in AM 1.5 is observed beyond 700 nm. As a part of this world-breaking research project, a cylinder-inspired gold resonator is also introduced. It includes a Gallium-Arsenide (GaAs) substrate and chromium (Cr) ground. It led to the development of efficient solar heaters for air and water systems, opening up significant opportunities for solar energy harvesting. [ABSTRACT FROM AUTHOR]

A novel design of an optical biosensor based on surface plasmon resonance using tin selenide (SnSe) and graphene is presented. Including biological solutions, the performance of the obtained biosensor over a wide range of refractive index variations is promising. It is designed such that its key parameters are optimized to detect different cancerous cells with high selectivity and sensing ability. The design and analysis of the sensor have been carried out by implementing a finite element method–based simulation platform. The results revealed that the designed sensor can provide a sensitivity of 121.0 deg.RIU−1, 134.2 deg.RIU−1, 142.9 deg.RIU−1, 143.6 deg.RIU−1, and 72.2 deg.RIU−1 for sensing skin, cervical, blood, adrenal gland, and breast cancerous cells respectively with maximum quality factor of 408 RIU−1 and a detection accuracy of 5.71. The results obtained using the proposed model of the SPR biosensor are promising. It could be a potential candidate for several sensing applications such as detecting different types of cancer disease in the early stages. Such detection is anticipated to save the lives of cancer patients. Comparing our results to work published recently, we were able to achieve an enhanced angular sensitivity (S) ranging from 72 to 143.6 deg.RIU−1, a detection accuracy (DA) ranging from 2.66 to 5.71, and a quality factor (QF) ranging from 190 to 408 RIU−1. [ABSTRACT FROM AUTHOR]

This study introduces a novel biosensor utilizing silver (Ag)–dielectric–black phosphorus (BP) as the foundation to analyze the surface plasmon resonance (SPR) system for alcohol detection for the first time. Silver (Ag) is employed as a metallic layer in the Kretschmann configuration of the proposed sensor to induce the generation of surface plasmons. The present study employs dielectric materials, namely lithium titanate (LiTiO3), potassium tantalite (KTaO3), bismuth silicon oxide (BSO), and zinc selenide (ZnSe), to safeguard the Ag material from oxidation. Additionally, 2D material of BP is used to augment the detecting capacity of the sensor. This study focuses on the detection of ethyl alcohol (ethanol) and propanol alcohol. To analyze the sensor's performance, the transfer matrix method is used with the help of angular interrogation technique. The proposed sensor performance is significantly enhanced by achieving a maximum sensitivity of 277.63°⁄RIU, a detection accuracy of 4.37, and a quality factor of 97.06 RIU - 1 for the optimized sensor design. Hence, the sensor has significant utility in the field of biological applications. [ABSTRACT FROM AUTHOR]

In this article, we have introduced an innovative sensor configuration employing a metasurface encompassing three rectangles configured into a star-shaped structure and multiple square-graphene elements—for accurate blood analysis. The suggested sensor architecture, characterized by its hierarchical structural configuration, offers several advantages crucial for accurate and reliable detection of target biomolecules. The star-shaped pattern, meticulously constructed with specific dimensions, significantly increases the surface area exposed to target compounds, thereby enhancing sensor sensitivity. Forensic science is at the core of investigations into crimes. It is undoubtedly crucial to modern legal structures. It is a constantly growing field that is always looking for new ways to increase the level of accuracy, sensitivity, and effectiveness of evidence examination. Terahertz (THz) spectra have recently developed as a sophisticated method with incredible potential in every aspect of forensics. A critical component of this endeavor is the development of THz sensors capable of detecting hemoglobin, a crucial protein in the evaluation of blood. The proposed sensor displays a remarkable level of sensitivity, with a maximum value of 300 GHzRIU−1 and a detection limit of 1.013 RIU−1. Moreover, the sensor demonstrates its capacity to detect subtle variations through its resolutions and Figure of Merit (FOM), quantified respectively as 0.268 and 1.796 RIU−1. [ABSTRACT FROM AUTHOR]

To satisfy the marking demand for microwave absorbing devices, we design an ultra-broadband nearly perfect absorber. The proposed absorber demonstrates absorption band from long to very long-wavelength ranges (15.7–37.9 µm). An average absorption efficiency of 95.16% and a satisfactory absorption bandwidth of 19.2 µm are achieved. The absorption with high absorptivity and large bandwidth is achieved through combined propagating surface plasmon (PSP) resonances in two directions and localized surface plasmon (LSP) resonances. By simulating and calculating the absorptivity, we demonstrate that the absorber possesses the properties of polarization independence and incident angle insensitivity. When the incident angle reaches 60°, the device still maintains a high absorptivity. Finally, the manufacturing process is illustrated, using radio frequency sputtering with dual guns or an E-beam. Compared with other related microwave absorbers, the proposed absorber balances the contradiction between absorption bandwidth and average absorption. We have strong confidence that the absorber has tremendous applications in many areas, such as infrared thermal emitters, imaging, and photodetectors. [ABSTRACT FROM AUTHOR]

A long-range surface plasmon biosensor (LRSPR) using the 2S2G/Teflon/Au MXene/Sensing medium (SM) is proposed for improve the imaging sensitivity. Here, the MXene layer is used to improve imaging sensitivity and protect against unwanted oxidation of Au layer. MXene having formula is Ti3C2Tx layered materials with hydrophilic nature, better stability, good conductivity and large surface area. The proposed LRSPR uses the high adsorption efficiency and high resolution. Numerically investigate the imaging sensitivity compared to the conventional surface plasmon sensor (cSPR) as well as systematic layer of proposed LRSPR sensor. The maximum imaging sensitivity of 10,465/RIU at 1.35 based RI of plasma sensing medium is achieved. The maximum electric field normalized at the interface between the Teflon-Au layer in the proposed sensor and the Au/MXene layer in the cSPR sensor. For the proposed LRSPR sensor, the penetration depth (PD) of the field into the sensing medium of 611.7 nm and 806.13 nm is obtained at Au-SM and MXene-SM interface for the sensing medium of 1.337 and 1.350. In addition, the figure of merit (FoM) as 193/RIU and 275.6/RIU is exhibited for the same sensing medium. [ABSTRACT FROM AUTHOR]

An innovative photonic crystal fiber (PCF) biosensor using surface plasmon resonance (SPR) to diagnose six distinct kinds of cancers (skin cancer, cervical cancer, adrenal gland cancer, blood cancer, and breast cancer types 1 and 2) in cells is demonstrated here and incorporates with two microchannels and a bimetallic configuration. The numerical analysis utilizes the finite element method (FEM) combined with perfectly matched layers (PML). The plasmonic material employed in the biosensor is gold (Au), and a supportive material, titanium dioxide (TiO2), is combined with Au. By combining these two materials, the sensor's performance is improved. The numerical calculations indicate that breast cancer type 2 has the highest wavelength sensitivity (24,285.71 nm/RIU) and amplitude sensitivity (3959 RIU−1). The rest of the cancer cells' wavelength sensitivities are 11,000.00 nm/RIU (skin cancer), 13,333.33 nm/RIU (cervical cancer), 15,000.00 nm/RIU (blood cancer), 17,142.85 nm/RIU (adrenal gland cancer), and 21,428.57 nm/RIU (breast cancer type 1). This advanced biosensor has several uses in biological sensing and medical technology, and it has the potential to revolutionize cancer identification and medical diagnosis. [ABSTRACT FROM AUTHOR]

The traditional and modified structures are simulated by the finite element method (FEM). In the modified structure, ten well-known add layers with complex refractive indexes (MgF2, SiO2, ITO, Si, ZnO, PLZT, GaAs, LNO, PZT, and TiN) are proposed over a thin film of gold metal. Due to the addition of the add layer, the stability of the proposed structure increases and also manipulates the performance parameters of the considered structure. Therefore, we investigated theoretically that the reflectance spectrum is a function of the incidence angle, and surface plasmon waves at the resonance angle were obtained. From the reflectance spectra, we obtained the maximum shift, i.e., 2.369° in Si, and the minimum shift, i.e., 1.484° for MgF2, from the considered add layer. Moreover, the full beam width is minimum, i.e., 5.1140°; the figure of merit is high, i.e., 27.109 a.u./RIU; detection accuracy is maximum, i.e., 0.292; and the quality factor is also high, i.e., 27.563 RIU−1 for the traditional SPR sensor among all considered structure. In addition, if we keep the complex refractive index (n + ik) of considered add layer remain constant and varying the thickness of considered add layer then the resonance angle shifts towards right angle, minimum reflectance value shift upwards, width of reflectance curve becomes broader, and penetration depth decreases. After that, the same observation is found if we keep thickness and imaginary part of complex refractive index remain constant but only real part of complex refractive index increases of considered add layer. But, when we keep the thickness of add layer and real part of complex refractive index remain constant and varying the imaginary part complex refractive index of the considered add layer then the resonance angle shifts towards right angle, minimum reflectance value decreases, and penetration depth (PD) value increases. After that, we calculated the performance parameters, i.e., field intensity at different interfaces (metal-sensing medium (M-S), metal-dielectric (M-D), and dielectric-sensing medium (D-S)), shift in resonance angle (∆θr), full beam width (FBW), sensitivity (S), detection accuracy (DA), quality factor (Q), figure of merit (FoM), and penetration depth (PD) for all the considered structures. From the obtained result, we have observed that the PD is maximum for MgF2, i.e., 2.96 nm, and minimum for GaAs, i.e., 0.26 nm, among all the structures considered. This comparative study will help to choose an add layer with a complex refractive index over a metal thin film in a SPR sensor for the detection of analytes or molecules present in the sensing medium. [ABSTRACT FROM AUTHOR]

This manuscript presents a Kretschmann configured long-range surface plasmon resonance (LRSPR) imaging sensor (structure: 2S2G prism-MgF2-Ag-PtSe2-BlueP/MoS2-SM) demonstrating ultrahigh imaging sensitivity, SImg. (23,250 RIU−1); detection accuracy, DA (50 Deg.−1); angular figure of merit, FoMAng. (1930.87 RIU−1); imaging figure of merit, FoMImg. (1,162,500 Deg.−1 RIU−1); and better penetration depth, PD (1129.4 nm), for sensing of biomolecules. The MATLAB and COMSOL simulation software are used for numerical analysis of the results. The effect of different dielectric buffer layers, DBLs (MgF2, LiF, Cytop & Teflon), and Ag/Au thin metal films on sensor performance has been substantiated to find the best suited DBL and metal film. The use of PtSe2 leads to further enhance sensor performance due to its high carrier mobility, tunable bandgap, chemical stability, and immunity to toxicity. Heterostructure of BlueP/MoS2 plays an important role in attachment of biomolecules due to larger surface area and higher optical adsorption efficiency (5%), quantum confinement effect of MoS2. Furthermore, heterostructure of BlueP/MoS2 leads to improve the sensor performance parameters due to high charge carrier transfer efficiency. Overall, larger PD of proposed LRSPR sensor is suitable to detect larger size biomolecules. Hence, the proposed sensor performance paves a way for its efficient use in field of biological molecule sensing. [ABSTRACT FROM AUTHOR]

Our research focuses on the development of a surface-plasmon sensor that uses a stationary surface plasmon, referred to as a "nonpropagating mode." This mode is observed when light is incident perpendicularly on a surface-plasmon sensor based on a metal diffraction grating. We performed a comprehensive analysis of the behavior of the surface-plasmon resonances within this nonpropagating mode, employing the rigorous coupled-wave analysis method. Using electron-beam lithography, sputtering, and a lift-off process, we fabricated such a surface-plasmon sensor and evaluated its optical properties rigorously. By combining simulations and experiments, we successfully utilized the nonpropagating mode to detect a liquid medium with a refractive index of 1.70. Simulations show that the nonpropagating mode arises due to a Fano resonance; i.e., to a resonant interaction between a localized surface plasmon generated at the edge of a metal grating strip during normal incidence and a propagating surface plasmon that occurs at the boundary between the metal diffraction grating and the measurement medium. The present results provide useful information for the advancement of surface-plasmon sensing technologies. [ABSTRACT FROM AUTHOR]

In this article, a surface plasmon resonance (SPR)-based refractive index sensor is proposed for the detection of colorectal cancer (CRC). The prism-based configuration has been employed to excite the surface plasmons (SPs). The structure of the proposed sensor consists of an Al–Cu bimetallic layer on the BK7 prism. To ensure contact between the metallic layer and the prism, an adhesive layer of TiO2 is used. Graphene layer is used above the bimetallic layer to improve its stability. In order to detect CRC, the healthy and infected tissues are utilized as the analyte media. The numerical simulations of the sensor have been performed using the transfer matrix method. The sensitivity, quality factor, and figure of merit (FOM) are the parameters that determine the performance of the proposed sensor, where FOM includes full width at half maxima (FWHM) and dip strength of the SPR curve. The number of graphene layers and thicknesses of the Al, Cu, and TiO2 layers have been optimized to achieve better performance of the sensor. The effect of incident angle on the performance of the sensor has also been studied. It has been found that a smaller incident angle gives better performance. The maximum value of the sensitivity, quality factor, and FOM obtained are 13,842.1 nm/RIU, 410.95 RIU−1, and 0.92, respectively. The proposed sensor would be a promising candidate for biosensing and medical diagnostics. [ABSTRACT FROM AUTHOR]

Tropical diseases present significant challenges to global health, particularly in resource-limited regions. Early and accurate detection of these diseases is vital for effective management and control. In recent years, metallic-based LSPR sensors have emerged as promising diagnostic tools for sensitive and rapid detection of tropical diseases. This comprehensive review aims to provide an in-depth analysis of the current state of research on metallic-based LSPR sensors for the detection of various tropical diseases. In this study, we focused on the connection between neglected tropical diseases (NTDs) and its risk using metallic-based LSPR sensors to identify potential inflammatory biomarkers. We conducted a literature search using PubMed, Web of Science, and Google Scholar. Only published materials written in English were considered, resulting in the identification of ∼ 220 articles. After a comprehensive evaluation, we selected 35 relevant ones. Our analysis revealed 35 links to neglected tropical diseases, providing valuable insights into their relationship using metallic-based LSPR sensors. Moreover, we explore the potential of metallic-based LSPR sensors in point-of-care testing and their integration with emerging technologies such as microfluidics and smartphone-based diagnostics. This review underscores the need for continued research efforts to develop affordable, sensitive, and user-friendly metallic-based LSPR sensors for early detection and surveillance of tropical diseases. [ABSTRACT FROM AUTHOR]

In this work, an efficient optical sensor is proposed for the sensitive detection of various pollutants in water. The suggested optical sensor is based on an indium fluoride (InF3) glass fabricated as a D-shaped optical fiber. The polished surface of the D-shaped fiber is coated with a gold grating to induce the surface plasmon resonance (SPR). The SPR depends on the optical properties of the polluted water analyte in physical contact with the grating. The proposed optical SPR fiber sensor operates within the mid-infrared (MIR) range (3000–4500 nm) to detect any slight change in the water refractive index (RI) due to any pollutants. The full vectorial finite element method (FVFEM) is utilized to calculate the modal properties of the reported sensor. High sensor sensitivity of 17,834 nm/RIU (refractive index units) is achieved for the detection of dissolution of nitric acid (HNO3) in water at a concentration of 14% v/v (volume/volume). Additionally, the reported sensor detects the dissolution of hydrogen peroxide (H2O2) in water investigated at concentrations of 15% v/v and 30% v/v, with sensitivities of 12,308 nm/RIU and 17,143 nm/RIU, respectively. Further, suspending polystyrene beads of diameter 0.1 μm in the water at a concentration of 10% v/v gives a maximum sensitivity of 5333 nm/RIU. Therefore, the proposed sensor provides a promising approach for the detection of water pollutants in the MIR wavelength regime, rather than the weaker response in the near infrared. [ABSTRACT FROM AUTHOR]

The present work focuses on the detection of dengue virus using a proposed copper (Cu) and black phosphorus (BP)–based SPR sensor. This proposed sensor is capable of detecting normal and infected blood samples containing plasma, platelets and hemoglobin. We studied the performance parameter at optimized Cu layer thickness of the proposed sensor by calculating that the maximum sensitivity is 150.55°/RIU, 226.73°/RIU and 295.58°/RIU at Rmin values with 57 nm, 57 nm and 51 nm thickness of Cu layer for the detection of plasma, platelet and hemoglobin in the blood sample of dengue malaria. The properties of BP combined with the unique plasmonic properties of SPR sensors can result in enhanced interactions between surface plasmons and incident light. These results are intended for improved sensitivity and remarkable figure of merit (FoM). We also calculated the electric field and penetration depth (PD) for the same sample. In this study, the normal and infected blood samples are successfully examined for the performance parameters for the plasma, platelets and hemoglobin. [ABSTRACT FROM AUTHOR]

This review presents the theory, configurations, and various applications of plasmonics in a variety of surface plasmon–based devices. It describes how light waves travel along the surface where metals and dielectrics meet, revealing the detailed reasons behind the phenomenon. Here, we have used the well-known Drude optical model, a widely accepted theoretical approach, to figure out how different materials behave by considering atoms as tiny vibrating dipoles. In this review, we have thoroughly looked at many aspects, all wrapped up in the concept of complex dielectric functions. We used Maxwell's equations customized for simple, non-magnetic materials to derive the above mentioned model, with the goal of helping to better grasp how surface plasmon polaritons are generated. In this research, we have organized the conditions needed for momentum matching by applying particular boundary conditions. Along with, we presented different techniques required for the generation of surface plasmon polaritons. We studied how metal and dielectric materials work together, by making comparisons to different optical devices along the way. Our main focus on the subject highlights the significant possibilities that this theory and research offers to various plasmonic applications. [ABSTRACT FROM AUTHOR]

Imidazole is a five-membered heterocyclic ring containing three carbon atoms, two nitrogen atoms, and two double bonds. Among two nitrogen atoms, one of which carries with a hydrogen atom is a pyrrole-type nitrogen atom, another is a pyridine type nitrogen atom. Hence, the imidazole ring belongs to the π electron-rich aromatic ring and can accept strong suction to the electronic group. Moreover, the nitrogen atom of the imidazole ring is coordinated with metal ions to form metal-organic frameworks. In recent years, because of imidazole compounds' unique optical properties, their applications have attracted more and more attention in optical analysis. Thus, this review has summarized the synthesis, characterization, and application with emphasis on the research progress of imidazole compounds in optical analysis, including fluorescence probe, colorimetric probe, electrochemiluminescence sensor, fiber optical sensor, surface plasmon resonance, etc. This paper will suggest the direction for the development of imidazole-containing sensors with high sensitivity and selectivity. [ABSTRACT FROM AUTHOR]

The present study conveyed an in-situ synthesis of silver nanoparticles (Ss-AgNPs) using Solanum sisymbriifolium aqueous leaf extract (SsLE) and their biological activities for the first time. The qualitative and quantitative analysis of SsLE imparted significant amounts of reducing entities/ secondary metabolites. A surface plasmon resonance peak at ∼430 nm of UV–visible spectrum evidenced the formation of Ss-AgNPs. The average particle size of the Ss-AgNPs was found to be 29.87 nm through particle size analyzer. Further, FE-SEM, HR-TEM and XRD analysis verified the spherical shape and high degree of crystallinity with face-centred cubic structure of Ss-AgNPs. The EDX, elemental mapping and FTIR spectral studies, confirmed that various phytochemicals/ metabolites of S. sisymbriifolium leaf extract participated in bio-reduction process and capping of Ss-AgNPs, which might be accountable for the antioxidant activities. Moreover, SsLE and Ss-AgNPs were found to be a rich source of antioxidants and exhibited effective DPPH, H 2 O 2 , ṄO scavenging activities along with Ferric ion reducing antioxidant power. The synthesized Ss-AgNPs showed significant antibacterial activity against gram-positive and gram-negative bacteria. In addition to this, Ss-AgNPs supported the degradation of methylene blue (a cationic dye), by performing as a strong photocatalyst under UV and solar irradiations. [Display omitted] • First time report on green-synthesis of AgNPs using S. sisymbriifolium leaf extract. • AgNPs possessed profuse antioxidant property as monitored by four antioxidant assays. • AgNPs showed enhanced antibacterial activity against Gram-negative bacteria. • AgNPs acted as a strong photocatalyst under UV and solar irradiation by degrading MB dye. [ABSTRACT FROM AUTHOR]

A surface plasmon resonance-based hollow core photonic crystal fiber (HC-SPR-PCF) is developed to detect gasoline adulteration with kerosene. The SPR-PCF sensor is fabricated via stack and draw, and atomic layer deposition (ALD). The performance of SPR-PCF sensors, such as sensitivity, loss, figure of merit (FoM), responsivity, and response time, are analysed experimentally in the wide refractive index (RI) range of 1.428–1.45. This experimental result shows that the proposed sensor with thin gold and aluminium oxide (Au + Al 2 O 3 ) plasmon active material exhibits a high amplitude sensitivity (321.59/RIU), low loss (0.0529 dB/cm), high responsivity (0.355875), and good FoM (1247.5/RIU). The presented experimental study has excellent potential in biochemical sensing applications due to its high sensitivity, low loss, linearity and fast response time. [ABSTRACT FROM AUTHOR]

Plasmonic-driven photocatalyst have outstanding solar driven surface plasmon resonance (SPR) characteristics, and it is a prospective approach to improve photocatalytic performance. Herein, plasmonic Co metal decorated SrTiO3: La/Cr hollow cubes was developed and constructed by template-free hydrothermal method. The photocatalyst possesses the merits of the hollow structure with large specific surface area and strong light absorption. The intimate contact between Co and SrTiO3: La/Cr promotes the interfacial charge transfer. Co-SrTiO3: La/Cr manifests the superior photocatalytic performance toward water splitting for hydrogen evolution compared with that of other cocatalyst. And the H2 evolution exceeds 210 μmol·g−1·h−1 under the optimum of the amount of 1.25wt% Co NPs. The mechanism of the enhanced performance comes from the improvement of light absorption in the visible-light region induced by SPR, as well as the efficient interfacial separation and transport of charge carriers on the photocatalyst facilitated by the local electromagnetic fields of plasmonic Co metal. [ABSTRACT FROM AUTHOR]

Background: Inflammatory macrophage infiltration plays a critical role in acute kidney disease induced by ischemia-reperfusion (IRI-AKI). Calycosin is a natural flavone with multiple bioactivities. This study aimed to investigate the therapeutic role of calycosin in IRI-AKI and its underlying mechanism. Methods: The renoprotective and anti-inflammatory effects of calycosin were analyzed in C57BL/6 mice with IRI-AKI and lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. RNA-seq was used for mechanism investigation. The molecular target of calycosin was screened by in silico methods and validated by surface plasmon resonance (SPR). Macrophage chemotaxis was analyzed using Transwell and agarose gel spot assays. Results: Calycosin treatment significantly reduced serum creatinine and urea nitrogen and attenuated tubular destruction in IRI-AKI mice. Additionally, calycosin markedly suppressed NF-κB signaling activation and the expression of inflammatory mediators IL-1β and TNF-α in IRI-AKI kidneys and LPS-stimulated RAW 264.7 cells. Interestingly, RNA-seq revealed calycosin remarkably downregulated chemotaxis-related pathways in RAW 264.7 cells. Among the differentially expressed genes, Ccl2/MCP-1, a critical chemokine mediating macrophage inflammatory chemotaxis, was downregulated in both LPS-stimulated RAW 264.7 cells and IRI-AKI kidneys. Consistently, calycosin treatment attenuated macrophage infiltration in the IRI-AKI kidneys. Importantly, in silico target prediction, molecular docking, and SPR assay demonstrated that calycosin directly binds to macrophage migration inhibitory factor (MIF). Functionally, calycosin abrogated MIF-stimulated NF-κB signaling activation and Ccl2 expression and MIF-mediated chemotaxis in RAW 264.7 cells. Conclusions: In summary, calycosin attenuates IRI-AKI by inhibiting MIF-mediated macrophage inflammatory chemotaxis, suggesting it could be a promising therapeutic agent for the treatment of IRI-AKI. [ABSTRACT FROM AUTHOR]

Nanomaterials based on metal oxides, especially Cu2O, have received much attention in recent years due to the many unique properties of the surface plasmon resonance they provide. The report presented the co‐precipitation method, a simple preparation method to produce Cu2O oxide particles. In addition, to improve the unique antibacterial properties of Cu2O, a proposed method is to attach Ag nanoparticles to the surface of Cu2O particles. The Cu2O and Cu2O−Ag particles were synthesized based on redox reactions using ascorbic acid (LAA) as a reducing agent. Moreover, in this experiment, two surfactants, polyethylene glycol 6000 (PEG 6000) and sodium dodecyl sulfate (SDS), were added during the manufacturing process to create particle samples and particle combinations with better properties than the original sample. Changes in the characteristics and properties of particle samples are determined by many different physical and chemical methods such as ultraviolet‐visible spectroscopy (UV‐Vis), infrared spectroscopy (IR), noise X‐ray radiation (XRD), scanning electron microscope (SEM), dynamic light scattering (DLS), energy dispersive X‐ray spectroscopy (EDS), and transmission electron microscopy (TEM). Finally, the activity against bacteria, including E. coli and S. aureus, was also tested using the agar well diffusion method to determine the zone of inhibition. The results improved the particle size value, which decreased by half to 200 nm when two additional surfactants, PEG and SDS, were added. In addition, the antibacterial ability has also been shown to increase significantly when the diameter of the bacterial inhibition zone increased significantly, reaching values of 20 mm (Cu2O/Ag/SDS) and 32 mm (Cu2O/Ag/PEG) for the E. coli bacterial strain. The initial test sample was only about 14 mm in size. The S. aureus bacterial strain also had a similar improvement trend after adding Ag to the Cu2O surface with the appearance of two surfactants, SDS and PEG. The inhibition zone diameter values reached the optimal value at 36 mm in the Cu2O/Ag/PEG particle combination sample compared to only the initial 26 mm in the Cu2O particle sample. Finally, the particle samples are added to the acrylic emulsion paint film to evaluate the changes. Positive results were obtained, such as improvement in adhesion (1.22 MPa), relative hardness (240/425), and sand drop resistance (100 L/mil) in the Cu2O/Ag/PEG particle combination sample, which showed the correctness and accuracy of the research. [ABSTRACT FROM AUTHOR]

Monoclonal gammopathies frequently associate with hemostatic alterations. Thrombotic events occur with high incidence particularly upon treatment, while in rarer cases hemorrhagic diathesis can be observed. The pathology of these tendencies could be caused by thrombocytopenia or hyperviscosity burden of circulating monoclonal antibodies. Studies also suggest interference of monoclonal antibodies with primary hemostasis. We isolated monoclonal whole IgG paraproteins from two myeloma patients to observe their effect on thrombin formation and fibrin polymerization. Monoclonal whole IgG was prepared from sera of two newly diagnosed untreated multiple myeloma patients and control normal plasma samples. Fibrin formation was measured using thrombin time and dilute prothrombin time tests and thrombin formation was detected with a fluorimetric thrombin generation assay. In addition, molecular interactions were investigated by surface plasmon resonance (SPR). Thrombin time was prolonged upon addition of monoclonal IgG even at 30 g/L by 12 %, increasing up to 36 % at 60 g/L concentration. Dilute prothrombin time was prolonged by 20 % even at 30 g/L. Thrombin generation assay indicated an impairment in thrombin formation at the presence of monoclonal IgG compared to polyclonal at equivalent concentration. By an SPR assay we determined that both clonality IgG preparations interacted with fibrinogen, however interaction with human thrombin was only detected with monoclonal immunoglobulins (KD=1.03 × 10-7 M). Here we provide evidence that isolated monoclonal whole IgG from myeloma patients can impair both fibrin and thrombin formation and we demonstrate by SPR assay that it interacts with components of the final phase of the coagulation system. [ABSTRACT FROM AUTHOR]

This study investigates the detection of organic compounds using a surface plasmon resonance (SPR) sensor comprising Zinc oxide (ZnO), Silver (Ag), and graphene oxide (GO) layers. Graphene oxide is chosen as topmost layer due to its impressive attributes, including a large surface area, robust light absorption, thermal stability, and biocompatibility. By optimizing the thickness of the ZnO and Ag, the performance of the sensor is enhanced. The proposed sensor configuration significantly improved the sensitivity and obtained the maximal value of 215°/RIU at minimum reflectance (Rmin). At a ZnO thickness of 20 nm and Ag thickness of 35 nm, the sensor achieves maximal sensitivity of 222.79/RIU for detecting the n-octane organic compound. This improved sensor design shows efficacy in detecting analytes with refractive index (RI) variations ranging from 1.33 to 1.39. Additionally, the proposed sensor demonstrated a limit of detection (LoD) of 5.65 RIU and figure of merit (FoM) of around 50.75/RIU, highlighting its high sensitivity, and detection accuracy. Furthermore, substantial penetration depths (PDs) of 219.71 nm for water and 211.11 nm for n-octane are obtained. This analysis highlights the exceptional performance of the proposed sensor, rendering it highly suitable for sensing applications in both industrial and biomedical domains. [ABSTRACT FROM AUTHOR]

In this paper, we propose a tilted fiber Bragg grating (TFBG) pH sensor based on polyaniline (PANI) reactive deposition film. The micron-scale thickness polyaniline film provides the sensor with good sensitivity, and it achieves measurement of pH values ranging from 2 to 12 by utilizing the pH-responsive mechanism of PANI and the refractive index characteristics of TFBG. Experimental results show that within the 2–12 pH range, the sensitivity of the TFBG surface plasmon resonance pH sensor based on PANI coating is − 0.03815, and results demonstrate, a linear correlation coefficient between wavelength and pH value reaching 0.98719. This indicates significant potential for future engineering applications in real-world pH measurement using this sensor. [ABSTRACT FROM AUTHOR]

This study proposed photonic crystal fiber sensors with two distinct plasmonic layers were proposed and compared in order to identify skin cancer cells in comparison to normal blood cells. In order to attain high sensitivity for the detection of this surface plasmon resonance (SPR)-based sensor, a comparison is made between several layers of Silver-Titanium dioxide and Gold-Titanium dioxide. In addition, the presence of a TiO2 layer helps to lessen the chemical instability of silver and improves the SPR effect. For the purpose of this work, a numerical analysis of the sensor was performed using the finite element technique. It is possible to quantify the confinement loss of two sensors, as well as their sensitivity to changes in amplitude and wavelength, by modifying some influential factors such as the diameter of the airhole and the thickness of the plasmonic layer (Ag, Au). This allows for the evaluation of the effectiveness of the sensors in detecting a target analyte. For the purpose of identifying skin cancer cells, the highest amplitude sensitivity of silver as a plasmonic layer is 610 RIU-1, and the maximum spectral sensitivity is 7500 nm/RIU. The greatest spectral sensitivity of gold as a plasmonic layer for the detection of skin cancer cells is 7000 nm/RIU, while the maximum amplitude sensitivity of gold is 800 RIU-1. In-depth discussion has been held regarding the manufacturing procedure for the sensor that has been proposed. When it comes to the detection of organic and biological compounds, this biosensor that is now under investigation demonstrates promising characteristics due to its stability and good sensitivity. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 causes COVID-19, a global health crisis with diverse symptoms, posing diagnostic challenges. The scarcity of testing equipment leads to long wait times for COVID-19 tests. To address this challenge, we propose a surface plasmon resonance biosensor configured as: Prism (BK7)/Copper (Cu)/Nickle (Ni)/graphene. This configuration proves advantageous for the detection of the SARS-CoV-2 virus. Addition of graphene as a 2D material enhances the sensitivity for detecting biomolecules. Graphene serves as a bio recognizing material, facilitating the binding of ample biomolecules on the sensing surface. Through optimization, we achieve a maximum sensitivity of 399.80°/RIU, coupled with remarkable detection accuracy and figure of merit. Hence, the proposed biosensor holds promise for biosensing applications, offering higher sensitivity and utilizing advanced fabrication techniques. [ABSTRACT FROM AUTHOR]

Over the past years, Surface Plasmon Resonance (SPR) has been used in various domains including medical diagnostics, chemical and biological sensing, and environmental monitoring. SPR-based biosensors have more advantages than other optical biosensors due to their rapid, label-free, and targeted detection capabilities. There have been challenges to designing SPR biosensors with enhanced performance and improved environmental adaptability, including considerations such as prism-metal bonding, biomolecule adhesion, and oxidation protection. This paper presents sensitivity and performance enhancement in an SPR biosensor based on Kretschmann configuration while using a low refractive index CaF2 glass prism, a zinc oxide (ZnO) layer, a gold-silver alloy (Au10Ag90), and a single layer of 2D graphene. Theoretical analysis shows that the use of a CaF2 prism and the alloy gives a good sensitivity of 280 ∘ / RIU . The sole addition of a ZnO layer improves this sensitivity to 320 ∘ / RIU . Further addition of a graphene layer to make the final proposed structure CaF2/ZnO/Au10Ag90/graphene/SM, improves sensitivity to 340 ∘ / RIU , giving a figure of merit value of 60.28 / RIU and a quality factor value of 102.48 / RIU . Despite supporting the SPR mode and enhancing sensitivity, ZnO improves prism-alloy bonding while graphene promises better biomolecule adhesion and improved oxidation protection. Overall, our proposed structure has better sensing performance compared to other designs in the literature. The high sensitivity makes our proposed biosensor suitable for the detection of tiny cancer bio-markers in body fluids, enabling early medical interventions. [ABSTRACT FROM AUTHOR]

In this article, we propose a novel surface plasmon resonance (SPR) sensor design with the combination of two-dimensional (2D) nanomaterials including copper, nickel, and graphene, along with a bonding layer of black phosphorous, to achieve significant enhancements in plasmonic performance. Theoretical analysis of the parameters has been performed using the Fresnel equations and Transfer Matrix method, based on the Kretschmann setup. For the CaF2 Prism/Cu/Ni/Graphene/BP/Sensing-Medium configuration, the optimized performance parameters include an angular sensitivity of 410°/RIU, a detection accuracy of 0.33789°, a figure of merit (FOM) of 138.538 RIU/deg, and a limit of detection of 2.439 for the medium being sensed at 633 nm. The utilization of both graphene and BP proves advantageous in increasing the SPR sensor's sensitivity since BP and graphene possess stronger adsorption energy, making it a more suitable candidate for actively binding biomolecules. The proposed device showcases considerable potential for the detection of large-sized molecules such as secretary vesicles and lysosomes. The numerical simulation has been performed in the COMSOL Multiphysics and MATLAB environment. [ABSTRACT FROM AUTHOR]

Bismuth-doped metal oxides exhibit favourable photocatalytic features when exposed to both sunlight and UV light. In this approach, Bi0/TiO2 and Bi+3/TiO2 photocatalysts were prepared and their structural and optical properties are analysed using various characterization techniques. These developed photocatalysts were further tested for the photocatalytic elimination of Nitrobenzene in UV light and sunlight and compared with the performance of bare TiO2. The catalyst Bi+3/TiO2 performed better in UV light with 72.31% degradation, and 4.74 × 10−6 mol.litre−1.min−1 initial rate of reaction. However, when exposed to sunlight, Bi0/TiO2 outperformed with 73.85% degradation, and 4.63 × 10−6 mol.min−1 initial rate of reaction. This significant increase in photocatalytic activity of Bi0/TiO2 under sunlight could be accredited to increased light harvesting and enhanced efficiency in charge carrier separation, both of which were made possible by bismuth-induced surface plasmon resonance. [ABSTRACT FROM AUTHOR]

Exploring photothermal nanomaterials is essential for new energy and biomedical applications; however, preparing materials with intense absorption, highly efficient light‐to‐heat conversion, and enhanced photostability still faces the enduring challenge. Herein, the study synthesizes atomic‐thin (≈1.6 nm) 2D copper sulfide (AT‐CuS) plasmonic nanocrystals and find its extraordinary photothermal conversion efficiency (PCE) reaching up to 94.3% at the second near‐infrared (NIR‐II) window. Photophysical mechanism studies reveal that the strong localized surface plasmon resonance (LSPR) and out‐of‐plane size effect of AT‐CuS induce strong optical absorption and non‐equilibrium carrier scattering, resulting in a significant carrier‐phonon coupling (7.18 × 1017 J K−1 s−1 m−3), ultimately enhancing the heat generation. Such a photothermal nanomaterial demonstrates at leastmes stronger NIR‐II photoacoustic (PA) signal intensity than that of most commonly used miniature gold nanorods, together with greater biocompatibility and photo‐/thermal‐stability, enabling noninvasive PA imaging of brain microvascular in living animals. This work provides an insight into the rational exploration of superb NIR‐II photothermal and photoacoustic agents for future practical utilizations. [ABSTRACT FROM AUTHOR]

Introduction: KNP-301 is a bi-specific fragment crystallizable region (Fc) fusion protein, which inhibits both C3b and vascular endothelial growth factor (VEGF) simultaneously for patients with late-stage age-related macular degeneration (AMD). The present study evaluated in vitro potency, in vivo efficacy, intravitreal pharmacokinetics (IVT PK), and injectability of KNP-301. Methods: C3b and VEGF binding of KNP-301 were assessed by surface plasmon resonance (SPR) and enzyme-linked immunosorbent assay (ELISA), and cellular bioassays. A laser-induced choroidal neovascularization (CNV) model and a sodium iodate-induced nonexudative AMD model were used to test the in vivo efficacy of mouse surrogate of KNP-301. Utilizing fluorescein angiography (FA) and spectral-domain optical coherence tomography (SD-OCT) scans, the reduction in disease lesions were analyzed in a CNV mouse model. In the nonexudative AMD mouse model, outer nuclear layer (ONL) was assessed by immunofluorescence staining. Lastly, intravitreal pharmacokinetic study was conducted with New Zealand white rabbits via IVT administration of KNP-301 and injectability of KNP-301 was examined by a viscosity test at high concentrations. Results: KNP-301 bound C3b selectively, which resulted in a blockade of the alternative pathway, not the classical pathway. KNP-301 also acted as a VEGF trap, impeding VEGF-mediate signaling. Our dual-blockade strategy was effective in both neovascular and nonexudative AMD models. Moreover, KNP-301 had an advantage of potentially less frequent dosing due to the long half-life in the intravitreal chamber. Our viscosity assessment confirmed that KNP-301 meets the criteria of the IVT injection. Conclusions: Unlike current therapies, KNP-301 is expected to cover patients with late-stage AMD of both neovascular and nonexudative AMD, and its long-term PK profile at the intravitreal chamber would allow convenience in the dosing interval of patients. [ABSTRACT FROM AUTHOR]

[Display omitted] β-Elemene (β-ELE), derived from Curcuma wenyujin , has anticancer effect on non-small cell lung cancer (NSCLC). However, the potential target and detail mechanism were still not clear. TFEB is the master regulator of lysosome biogenesis. Ferroptosis, a promising strategy for cancer therapy could be triggered via suppression on glutathione peroxidase 4 (GPX4). Weather TFEB-mediated lysosome degradation contributes to GPX4 decline and how β-ELE modulates on this process are not clear. To observe the action of β-ELE on TFEB, and the role of TFEB-mediated GPX4 degradation in β-ELE induced ferroptosis. Surface plasmon resonance (SPR) and molecular docking were applied to observe the binding affinity of β-ELE on TFEB. Activation of TFEB and lysosome were observed by immunofluorescence, western blot, flow cytometry and qPCR. Ferroptosis induced by β-ELE was observed via lipid ROS, a labile iron pool (LIP) assay and western blot. A549TFEB KO cells were established via CRISPR/Cas9. The regulation of TFEB on GPX4 and ferroptosis was observed in β-ELE treated A549WT and A549TFEB KO cells, which was further studied in orthotopic NOD/SCID mouse model. β-ELE can bind to TFEB, notably activate TFEB, lysosome and transcriptional increase on downstream gene GLA, MCOLN1, SLC26A11 involved in lysosome activity in EGFR wild-type NSCLC cells. β-ELE increased GPX4 ubiquitination and lysosomal localization, with the increase on lysosome degradation of GPX4. Furthermore, β-ELE induced ferroptosis, which could be promoted by TFEB overexpression or compromised by TFEB knockout. Genetic knockout or inactivation of TFEB compromised β-ELE induced lysosome degradation of GPX4, which was further demonstrated in orthotopic NSCLC NOD/SCID mice model. This study firstly demonstrated that TFEB promoted GPX4 lysosome degradation contributes to β-ELE induced ferroptosis in EGFR wild-type NSCLC, which gives a clue that TFEB mediated GPX4 degradation would be a novel strategy for ferroptosis induction and NSCLC therapy. [ABSTRACT FROM AUTHOR]

In this paper, synthetically scaled-up degenerately n-type doped indium tin oxide (Sn:In2O3) nanocrystals are described as highly transparent conductive materials possessing both optoelectronic and crystalline properties. With tin dopants serving as n-type semiconductor materials, they can generate free-electron carriers. These free electrons, vibrating in resonance with infrared radiation, induce strong localized surface plasmon resonance (LSPR), resulting in efficient infrared absorption. To commercialize products featuring Sn:In2O3 with localized surface plasmon resonance, a scaled-up synthetic process is essential. To reduce the cost of raw materials during synthesis, we aim to proceed with synthesis in a large reactor using industrial raw materials. Sn:In2O3 can be formulated into ink dispersed in solvents. Infrared-absorbing ink formulations can capitalize on their infrared absorption properties to render opaque in the infrared spectrum while remaining transparent in the visible light spectrum. The ink can serve as a security ink material visible only through infrared cameras and as a paint absorbing infrared light. We verified the transparency and infrared absorption properties of the ink produced in this study, demonstrating consistent characteristics in scaled-up synthesis. Due to potential applications requiring infrared absorption properties, it holds significant promise as a robust platform material in various fields. [ABSTRACT FROM AUTHOR]

To improve the efficiency of cyclodextrins as carotenoid carriers, the kinetics and thermodynamics of the inclusion complex formation between modified β-cyclodextrin (βCD-NH2) and β-carotene (βCT) were studied using surface plasmon resonance (SPR) at pH 7.4 and theoretical calculations. The observed dissociation rate of the [βCD-NH2/βCT]° inclusion complex is small (2.59 × 1 0 - 1 s - 1 ), indicating that βCD-NH2 only interacted with the βCT ionone group to form inclusion complex. The βCD-NH2/βCT binding constant is 2.80 × 1 0 4 Lmol - 1 (at 298.15 K), and its temperature dependence indicates that the [βCD-NH2/βCT]° formation is driven by hydrophobic interactions ( Δ H ∘ = 28.83 kJ l - 1 and T Δ S ∘ = 54.21 kJ l - 1 ) caused mainly by the βCT end group desolvation. In contrast, the formation of the [βCD-NH2/βCT]‡ activated complex via association between free molecules and dissociation of [βCD-NH2/βCT]° occurred with the overcoming of an energy barrier ( E a ‡ = 40.77 kJ mol - 1 and E d ‡ = 11.94 kJ l - 1 ) and decrease in entropy ( T Δ S a ‡ = - 11.70 kJ l - 1 and T Δ S d ‡ = - 65.92 kJ l - 1 ). [ABSTRACT FROM AUTHOR]

Lytic polysaccharide monooxygenase (LPMO) of Auxiliary Activity 9 family has great potential for lignocellulose biomass degradation, and obtaining AA9 LPMOs with high catalytic activity and thermalstability is necessary for its industrial application. In this study, rational design and molecular modification was conducted on AnLPMO15g from Aspergillus niger to boost its performance on lignocellulose hydrolysis. The catalytic performance of mutant AnLPMO15g-293 (C293F) and AnLPMO15g-351 (S351F) with increased α-helix content in the secondary structure were improved. The catalytic efficiency (Kcat/Km) of C293F and S351F on 2,6-dimethoxyphenol was 1.27 and 1.17 times higher than that of AnLPMO15g respectively, and their activities on Avicel® increased by 81.17% and 40.78%, respectively. The half-life of C293F and S351F at 55 ℃ was 1.5 and 2.5 times longer than that of AnLPMO15g. Surface plasmon resonance analysis showed that the association velocity constant (Ka) of S351F increased tenfold compared with that of AnLPMO15g, indicating the substrate affinity of S351F was significantly improved. When C293F and S351F acted together with cellulase on straw powder, the reducing sugar yields increased by 1.81 and 1.53 times and the synergistic degree increased 30.7% and 11.8%, respectively. This study provides a good alternative for preparing efficient enzyme cocktails to hydrolyze lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

This manuscript presents a Kretschmann configured long-range surface plasmon resonance (LRSPR) imaging sensor (structure: 2S2G prism-MgF2-Ag-PtSe2-BlueP/MoS2-SM) demonstrating ultrahigh imaging sensitivity, SImg. (23,250 RIU−1); detection accuracy, DA (50 Deg.−1); angular figure of merit, FoMAng. (1930.87 RIU−1); imaging figure of merit, FoMImg. (1,162,500 Deg.−1 RIU−1); and better penetration depth, PD (1129.4 nm), for sensing of biomolecules. The MATLAB and COMSOL simulation software are used for numerical analysis of the results. The effect of different dielectric buffer layers, DBLs (MgF2, LiF, Cytop & Teflon), and Ag/Au thin metal films on sensor performance has been substantiated to find the best suited DBL and metal film. The use of PtSe2 leads to further enhance sensor performance due to its high carrier mobility, tunable bandgap, chemical stability, and immunity to toxicity. Heterostructure of BlueP/MoS2 plays an important role in attachment of biomolecules due to larger surface area and higher optical adsorption efficiency (5%), quantum confinement effect of MoS2. Furthermore, heterostructure of BlueP/MoS2 leads to improve the sensor performance parameters due to high charge carrier transfer efficiency. Overall, larger PD of proposed LRSPR sensor is suitable to detect larger size biomolecules. Hence, the proposed sensor performance paves a way for its efficient use in field of biological molecule sensing. [ABSTRACT FROM AUTHOR]

In this study, a chemical sensor based on silver nanoparticles (AgNPs) synthesized with Cucumis melo juice extract was presented for the determination of sulfide ions. The biosynthesized AgNPs, whose solution color was yellow, exhibited a sharp surface plasmon resonance peak at 405 nm. The addition of sulfide ions changed the surface properties of the AgNPs, resulting in a decrease in the absorbance intensity of the AgNPs, and the color of the solution changed from yellow to colorless. The response of the sensor to sulfide ions was linear in the concentration range of 0.5–11.5 µM, and the detection limit for this determination was 0.1 µM. The developed sensor was applied to detect sulfide ions in real water samples and showed excellent recoveries in the range of 98.7–103.5%. Furthermore, the AgNPs showed excellent selectivity toward sulfide ions. This assay is capable of qualitative and quantitative assessment of sulfide ions in environmental samples. [ABSTRACT FROM AUTHOR]

There is a growing need for precise and rapid detection methods in fields such as biomedical diagnostics, environmental monitoring, and chemical analysis. Surface plasmon resonance (SPR) sensors have been used for the detection and quantification of a wide range of analytes, including biomolecules, chemicals, and gases, in real-time. Despite the promising capabilities of SPR sensors, there remains a gap in creating a balance between having a large enough area to capture a significant number of analytes for detection and being small enough to ensure high sensitivity. This research aims to explore the design of a D-shaped SPR-based optical fiber sensor, focusing on the use of copper, gold, and silver thin films at optimized width and thickness of 10 µm and 45 nm, respectively, to improve the sensor's performance. Employing a computational approach, this study examines the influence of the optimized width and refractive indices of metallic films on the sensor's characteristics. The 10 µm width of the metallic thin film has been found to produce an optimal balance between the sensitivity and the dynamic range of the sensor. Leveraging on the ratio of the real and imaginary parts of the dielectric constant of the thin film metal provides insight into the optical properties and sensitivity at certain wavelengths. Within an analyte refractive index range of 1.37–1.42 and a wavelength range of 650–1200 nm, results indicate that silver outperforms gold and copper at the optimized width with a wavelength sensitivity, and detection accuracy of 12,300 nmRIU−1, and 3.075, respectively. By optimizing the width of the metal thin film at 10 µm, a highly sensitive D-SPR is designed, allowing for enhanced sensor detection capabilities for a wide range of bioanalytes. [ABSTRACT FROM AUTHOR]

In this study, an ultra-wideband absorber spanning from UV-B to middle-IR was designed and analyzed using a novel structure. The multilayer metamaterial, arranged from bottom to top, consisted of an Al metal layer, a lower SiO2 layer, a graphite layer, another SiO2 layer, a thin Ti layer, and a top SiO2 layer. The top layer of SiO2 had a 200 nm square cavity etched out, and then a square Ti nanopillar and a square Ti hollow outside a Ti nanopillar were embedded. This specific arrangement was chosen to maximize the absorption properties across a broad spectrum. The absorption spectrum of the designed absorber was thoroughly analyzed using the commercial finite element analysis software COMSOL Multiphysics® (version 6.0). This analysis confirmed that the combination of these various components achieved perfect absorption and an ultra-wideband response. The synergistic interaction between the layers and the nanopillars structure contributed significantly to the absorber's efficiency, making it a promising candidate for applications requiring broad-spectrum absorption. The comprehensive analyses of the parameters for different structures demonstrated that the effects of guided-mode resonance, coupling resonance, optical impedance matching, and propagating surface plasmon resonance existed in the investigated structure. The optimal model, determined through analyses using COMSOL Multiphysics®, showed that the broadband absorption in the range of 270 to 3600 nm, spanning from UV-B to middle-IR, exceeded 90.0%. The average absorption rate within this range was 0.967, with the highest reaching a near-perfect absorptivity of 99.9%. We also compared three absorption spectra in this study: the t1–t6 flat structure, the t1–t5 flat structure with t6 featuring a square cavity, and the structure proposed in this study. This demonstrates that a square nanopillar and a square hollow embedded in a square cavity can enhance the absorptive properties of the absorber. [ABSTRACT FROM AUTHOR]

Plasmonic applications have traditionally relied on noble metals such as gold (Au) and silver (Ag) for their excellent plasmonic performance in the visible and near-infrared spectrum. However, these metals are costly, scarce, and have limitations such as low stability (Ag) and interband transition losses, which restrict their spectral range. To address these issues, alternative plasmonic materials have been explored. One such material is aluminum (Al), which is inexpensive, abundant, and exhibits remarkable plasmonic properties in the UV region as well as wide tunability. Al is also compatible with complementary metal–oxide semiconductor (CMOS) fabrication processes and is very stable due to its ultrathin native oxide layer. Alloying different metals can combine their advantageous properties, resulting in enhanced tunable optical characteristics. This study investigates the LSPR properties of AgAl alloy nanoparticles grown after the annealing of precursor AgAl bilayer films. Interestingly, LSPRs were also observed in some cases for the as-deposited bilayers. The experimental results were complemented with simulations conducted via the rigorous coupled-wave analysis (RCWA) method. The investigated materials could be potentially useful for applications in energy harvesting or color printing. [ABSTRACT FROM AUTHOR]

Background: Paclitaxel is a widely used cancer treatment drug that has a significant inhibitory effect on cervical cancer cells (HeLa cells). This study aims to investigate the effects of paclitaxel on HeLa cells and evaluate the application of terahertz (THz) spectroscopy and surface plasmon resonance (SPR) biosensors in this process. Methods: We utilized an SPR biosensor in conjunction with THz spectroscopy to measure the terahertz absorbance spectra of HeLa cells exposed to various concentrations of paclitaxel. The minimum number of cells used for detection was 15.25 × 105. At the same time, cell proliferation levels were assessed through proliferation assays and compared with the terahertz spectroscopy data. Results: The experimental results indicated that with the increasing concentration of paclitaxel, the terahertz absorbance spectra of HeLa cells exhibited a blue shift, and cell proliferation was significantly inhibited. The results of the proliferation assays were consistent with the terahertz spectroscopy data, validating the effectiveness of this method. Conclusion: This study demonstrates that the combination of THz spectroscopy and SPR biosensors is a promising technology that can provide a simple, rapid, and low-cost method for studying chemistry–biology relationships, especially in the field of drug evaluation. [ABSTRACT FROM AUTHOR]

During the process of terahertz (THz) wave generation via femtosecond laser filamentation in air, as well as through the mixing of THz waves with externally injected plasma filaments, THz waves engage in interactions with the plasma. A characteristic feature of this interaction is the modulation of the THz radiation spectrum by the plasma, which includes the generation of THz spectral dips. This information is essential for understanding the underlying mechanisms of THz–plasma interactions or for inferring plasma parameters. However, a current debate exists on the number of THz spectral dips observed after the interaction, with different opinions of single versus multiple dips, thus leaving the interaction mechanisms still ambiguous. In this work, we retrospectively analyzed the experimental appearance of multiple dips in the THz spectrum and found that the current observations of such dips are predominantly a result of the water vapor absorption with a low spectral resolution. Additionally, we observed that altering the acquisition width of the temporal THz signal also influenced the dips' number. Hence, in future research, simultaneous attention should be paid to the following two aspects of THz–plasma interactions: (1) It is necessary to ensure a sufficiently wide time-domain window to accurately represent the spectral dip characteristics. (2) The spectral dips should be carefully distinguished from the water absorption lines before being further studied. On the other hand, for the case of a single dip in the THz spectrum, we also put forward a new viewpoint of the resonance between surface plasmon waves and THz waves, which should also be taken into consideration in future studies. [ABSTRACT FROM AUTHOR]

In this study, we systematically investigate theoretically and experimentally the plasmonic effect and roles of big and small gold nanoparticles (Au NPs) within a mixed solution. The polydisperse solution was initially prepared by mixing small (10, 30 nm) Au NPs with larger ones (50, 80 nm), followed by measuring the extinction using ultraviolet–visible (UV-vis) spectroscopy. The experimental results clearly showed that the extinction of the mixed solution is predominantly influenced by the presence of the larger NPs, even though their quantity is small. Subsequently, we conducted simulations to explore the plasmonic properties of Au NPs of different sizes as well as their mixings and to validate the experimental results. To explain the deviation of the extinction spectra between experimental observations and simulations, we elaborated a simulation model involving the mixture of spherical Au NPs with ellipsoidal NPs, thus showing agreement between the simulation and the experiment. By performing simulations of plasmonic near-field of NPs, our investigation revealed that the maximal electric field intensity does not occur precisely at the plasmonic resonant wavelength but rather at a nearby redder wavelength. The optimal size of the Au NP dispersed in water for achieving the highest field enhancement was found to be 60 nm, with an excitation wavelength of 553.7 nm. These interesting findings not only enrich our understanding of plasmonic NPs' optical behavior but also guide researchers for potential applications in various domains. [ABSTRACT FROM AUTHOR]

Bacteria are capable of remarkable adaptations to their environment, including undesirable bacterial resistance to antibacterial agents. One of the most serious cases is an infection caused by multidrug-resistant Staphylococcus aureus, which has unfortunately also spread outside hospitals. Therefore, the development of new effective antibacterial agents is extremely important to solve the increasing problem of bacterial resistance. The bacteriolytic enzyme autolysin E (AtlE) is a promising new drug target as it plays a key role in the degradation of peptidoglycan in the bacterial cell wall. Consequently, disruption of function can have an immense impact on bacterial growth and survival. An in silico and in vitro evaluation of iminosugar derivatives as potent inhibitors of S. aureus (AtlE) was performed. Three promising hit compounds (1, 3 and 8) were identified as AtlE binders in the micromolar range as measured by surface plasmon resonance. The most potent compound among the SPR response curve hits was 1, with a KD of 19 μM. The KD value for compound 8 was 88 μM, while compound 3 had a KD value of 410 μM. [ABSTRACT FROM AUTHOR]

Knowledge of the time of deposition is pivotal in forensic investigations. Recent studies show that changes in intrinsic fluorescence over time can be used to estimate the age of body fluids. These changes have been attributed to oxidative modifications caused by protein–lipid interactions. This pilot study aims to explore the impact of these modifications on body fluid fluorescence, enhancing the protein–lipid model system for age estimation. Lipid and protein oxidation markers, including protein carbonyls, dityrosine, advanced glycation end-products (AGEs), malondialdehyde (MDA), and 4-hydroxynonenal (HNE), were studied in aging semen, urine, and saliva over 21 days. Surface plasmon resonance imaging (SPRi), enzyme-linked immunosorbent assay (ELISA), and fluorescence spectroscopy were applied. Successful detection of AGE, dityrosine, MDA, and HNE occurred in semen and saliva via SPRi, while only dityrosine was detected in urine. Protein carbonyls were measured in all body fluids, but only in saliva was a significant increase observed over time. Additionally, protein fluorescence loss and fluorescent oxidation product formation were assessed, showing significant decreases in semen and saliva, but not in urine. Although optimization is needed for accurate quantification, this study reveals detectable markers for protein and lipid oxidation in aging body fluids, warranting further investigation. [ABSTRACT FROM AUTHOR]

By introducing a novel photothermal radiator that effectively harnesses diffused light through plasmonic Fe3O4@Cu2−xS nanoparticles, it is sought to offer a sustainable solution for maintaining comfortable indoor temperatures without heavy reliance on traditional solar sources. The approach involves the use of ultraviolet (UV) and infrared (IR) lights to photothermally activate transparent Fe3O4@Cu2−xS thin films, showcasing a proactive strategy to optimize energy capture even in low‐light scenarios such as cloudy days or nighttime hours. This innovative technology carries immense potential for energy‐neutral buildings, paving the way to reduce dependence on external energy grids and promoting a more sustainable future for indoor heating and comfort control. The developed photothermal radiator incorporates multiple transparent thin films infused with plasmonic Fe3O4@Cu2−xS nanoparticles, known for their robust UV and IR absorptions driven by localized surface plasmon resonance. Through the application of UV and IR lights, these thin films efficiently convert incident photons into thermal energy. The experiments within a specially constructed diffused light photothermal box, designed to simulate indoor environments, demonstrate the system's capability to raise temperatures above 50 °C effectively. This pioneering photothermal radiator offers a promising pathway for sustainable heat generation in indoor spaces, harnessing ubiquitous diffused light sources to enhance energy efficiency. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 infection can induce multisystem inflammatory syndrome in children, which resembles superantigen-induced toxic shock syndrome. Recent work has suggested that the SARS-CoV-2 spike (S) protein could act as a superantigen by binding T cell receptors (TCRs) and inducing broad antigen-independent T cell responses. Structure-based computational modeling identified potential TCR-binding sites near the S receptor-binding domain, in addition to a site with homology to known neurotoxins. We experimentally examined the mechanism underpinning this theory--the direct interaction between the TCR and S protein. Surface plasmon resonance of recombinantly expressed S protein and TCR revealed no detectable binding. Orthogonally, we pseudotyped lentiviruses with SARS-CoV-2 S in both wild-type and prefusion-stabilized forms, demonstrated their functionality in a cell line assay, and observed no transduction, activation, or stimulation of proliferation of CD8+ T cells. We conclude that it is unlikely that the SARS-CoV-2 spike protein engages nonspecifically with TCRs or has superantigenic character. [ABSTRACT FROM AUTHOR]