Search

Accurate diagnostic and serology assays are required for the continued management of the COVID-19 pandemic yet spike protein mutations and intellectual property concerns with antigens and antibodies used in various test kits render comparability assessments difficult. As the use of common, well-characterized reagents can help address this lack of standardization, the National Research Council Canada has produced two protein reference materials (RMs) for use in SARS-CoV-2 serology assays: biotinylated human angiotensin-converting enzyme 2 RM, ACE2-1, and SARS-CoV-2 Omicron BA.4/5 spike protein RM, OMIC-1. Reference values were assigned through a combination of amino acid analysis via isotope dilution liquid chromatography tandem mass spectrometry following acid hydrolysis, and ultraviolet–visible (UV–Vis) spectrophotometry at 280 nm. Vial-to-vial homogeneity was established using UV–Vis measurements, and protein oligomeric status, monitored by size exclusion liquid chromatography (LC-SEC), was used to evaluate transportation, storage, and freeze–thaw stabilities. The molar protein concentration in ACE2-1 was 25.3 ± 1.7 µmol L−1 (k = 2, 95% CI) and consisted almost exclusively (98%) of monomeric ACE2, while OMIC-1 contained 5.4 ± 0.5 µmol L−1 (k = 2) spike protein in a mostly (82%) trimeric form. Glycoprotein molar mass determination by LC-SEC with multi-angle light scattering detection facilitated calculation of corresponding mass concentrations. To confirm protein functionality, the binding of OMIC-1 to immobilized ACE2-1 was investigated with surface plasmon resonance and the resulting dissociation constant, KD ~ 4.4 nM, was consistent with literature values. [ABSTRACT FROM AUTHOR]

This study investigates the influence of LED radiation intensity on the photodeposition of gold nanoparticles onto TiO2 substrates, examining their physicochemical properties and photocatalytic activities. Utilizing a range of radiation intensities and wavelengths, TiO2-Au composites were synthesized and characterized through techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS). The deposition process, markedly enhanced by shorter wavelengths and higher intensities, efficiently formed gold nanoparticles. This research distinctly highlights observable morphological changes in the nanoparticles; increased radiation intensity not only augmented the size but also altered their shape from spherical to hexagonal. These morphological transformations significantly improve the composites' light absorption and catalytic properties due to the surface plasmon resonance of the gold nanoparticles. Photocatalytic assessments, using metronidazole as a model pollutant, demonstrated that composites prepared with higher LED intensities showed significantly enhanced degradation capabilities compared to those synthesized with lower intensities. The findings underscore that manipulating photodeposition parameters can critically influence the structural and functional properties of TiO2-Au composites, potentially advancing their applications in environmental remediation and solar energy utilization. [ABSTRACT FROM AUTHOR]

Purpose: The unsatisfactory efficacy of PD-L1 antibodies in glioblastoma (GBM) is largely due to the temporal and spatial heterogeneity of PD-L1 expression. Molecular imaging can enhance understanding of the tumor immune microenvironment and guide immunotherapy. However, highly sensitive imaging agents capable of effectively visualizing PD-L1 heterogeneity are limited. This study introduces a novel PET tracer, offering improved imaging of PD-L1 heterogeneity in GBM xenografts, with a comparative analysis to [18F]AlF-NOTA-WL12. Methods: [18F]AlF-NOTA-PCP2 was synthesized with high purity and its affinity for PD-L1 was characterized using surface plasmon resonance (SPR) and cell binding assays. Its specificity for PD-L1 was evaluated both in vitro using various cell lines and in vivo with GBM xenograft models in NOD/SCID mice. PET/CT imaging was conducted to evaluate the tracer's biodistribution, pharmacokinetics, and ability to quantify tumoral spatial heterogeneity of PD-L1 expression. A focused comparative analysis between [18F]AlF-NOTA-PCP2 and [18F]AlF-NOTA-WL12 was conducted, examining binding affinity, biodistribution, pharmacokinetics, and imaging effectiveness in GBM xenografts. Additionally, human radiation dosimetry estimates compared the safety profiles of both tracers. Results: [18F]AlF-NOTA-PCP2 demonstrated high radiochemical purity (> 95%) and a strong affinity for PD-L1, comparable to [18F]AlF-NOTA-WL12. In vitro and in vivo studies confirmed its specificity for PD-L1, with increased uptake in PD-L1 expressing cells and tumors. Toxicological profiles indicated no significant abnormalities in serum biochemical indicators or major organ tissues. MicroPET/CT imaging showed [18F]AlF-NOTA-PCP2's effectiveness in visualizing PD-L1 expression levels and spatial heterogeneity in GBM xenografts. Comparative studies revealed [18F]AlF-NOTA-PCP2's improved pharmacokinetic properties, including higher tumor-to-blood ratios and lower nonspecific liver uptake, as well as reduced radiation exposure compared to [18F]AlF-NOTA-WL12. Conclusion: [18F]AlF-NOTA-PCP2 distinguishes itself as an exceptionally sensitive PET/CT tracer, adept at non-invasively and accurately quantifying PD-L1 expression and its spatial heterogeneity in tumors, especially in GBM. Its favorable pharmacokinetic properties, safety profile, and high affinity for PD-L1 highlight its potential for enhancing the precision of cancer immunotherapy and guiding individualized treatment strategies. While promising, its clinical translation, especially in brain imaging, necessitates further validation in clinical trials. [ABSTRACT FROM AUTHOR]

Herein, a newly synthesized intermediate, piperazine-based Schiff base (PBSB) gas sensor was fabricated by the Schiff base condensation of amino functionalized methylpiperazine with aromatic aldehyde containing nitro substituent. This organic sensor material was structurally identified with spectroscopic techniques such as FTIR, HRMS, 1H- and 13C-NMR. The designed sensor candidate was explored for its optical response to chlorinated volatile organic compounds, namely trichloroethylene, dichloromethane and chloroform in the light of structure–property relationship investigation by using surface plasmon resonance (SPR) technique. The results showed that Schiff bases could be candidates for chlorinated vapour sensing materials with their good response and reversibility. Concordantly, compound PBSB exhibited good response against chlorinated solvent vapours aided by the electron-withdrawing group on benzene ring that promoted better intermolecular interactions and opened up a new strategy to create a novel set of responsive materials for gas sensing applications. In addition, the adsorption kinetics of SPR data obtained from PBSB spun film on exposure to these chlorinated vapours at different concentrations was also evaluated using the Elovich Model. The values of the initial adsorption rate, a and Elovich constant, b were analysed depending on the concentration values and the highest values were obtained for dichloromethane between 372.92 and 4377.53 ppm/mm2. [ABSTRACT FROM AUTHOR]

Antibiotic success rates are decreasing as drug-resistant bacteria become more prevalent, prompting the development of new therapeutic drugs. Herein, we demonstrated the antimicrobial activity of sarsaparilla root extract fabricated silver nanoparticles (sAgNPs). The UV–Visible spectra revealed that the surface Plasmon resonance maxima of sAgNPs were at 415 nm. Transmission electron microscopy confirms that the particles are spherical with size of 12–35 nm. The minimum inhibitory concentration (MIC) of sAgNPs against Escherichia coli, uropathogenic Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus was 62.5, 62.5, 62.5, 62.5, 125 and 125 µM, respectively. At 1X MIC, sAgNPs induces excess reactive oxygen species (ROS) production and disturbs the bacteria membrane intergity, causing cytoplamic membrane depolarization. Interestingly, antibacterial activity of sAgNPs was considerably reduced in the presence of an antioxidant, N-acetyl cysteine, suggesting that ROS-induced membrane damage is a plausible cause of cell death. In contrast to many studies that only report the in vitro activity of NPs, we determined the in vivo antibacterial efficacy using the zebrafish model. It was found that sAgNPs protect fish from infection by inhibiting bacterial growth and eliminating them from the fish. In addition, the catalytic potential of sAgNPs for wastewater decontamination was demonstrated by degrading organic pollutants such as methyl orange, congo red, reactive black, and acid blue. The pollutants degraded in less than 10 min, and the reaction follows pseudo-first-order kinetics. As a proof of concept, the catalytic potential of sAgNPs in degrading mixed dyes to satisfy industrial wastewater treatment needs was established. In summary, sAgNPs have the potential to act as nanocatalysts and nano-drugs, addressing key challenges in medical and environmental research. [ABSTRACT FROM AUTHOR]

The scorpion-derived peptide margatoxin (MgTx) can make it possible to create novel and targeted medications for treatment of cancer. In this study, for the first time, we report an investigation of the human serum albumin (HSA) protein interaction with MgTx in aqueous solution. For this, biophysical methods including spectral, surface plasmon resonance (SPR), zeta potential and also in silico molecular docking technique at physiological conditions were used for examining kinetic binding and thermodynamic data. This interaction was done for a series of MgTx concentrations at three temperatures. The comparison of the KD kinetic value at 308 ° K and 298 ° K in SPR and UV spectroscopy shows that the complex between the MgTx and HSA has high strength at lower temperatures. The resulted positive data for ΔH and ΔS show that the major interaction force involved in the formation of the MgTx/HSA complex is hydrophobic forces. Also, the decreasing of zeta-potential values by adding of MgTx concentrations confims that the MgTx molecules could bind to HSA more by hydrophobic forces. In addition, according to the docking results, there are a very small number of strong interactions such as hydrogen bonds and salt bridges compared to the hydrophobic forces in the HSA and MgTx interaction. [ABSTRACT FROM AUTHOR]

Photocatalysis technology is considered as a most promising method to decompose organic pollutant since the inexhaustible solar energy and facile reaction condition. Herein, a series of flower-like Ag/AgCl/BiOCl photocatalysts are successfully synthesized via hydrothermal and photochemical deposition method. All the samples are investigated and characterized by X-Ray diffraction, Scanning electron microscopy, transmission electron microscope, ultraviolet–visible spectroscopy and Photoluminescence to insight into the microstructures and optical properties. During the photocatalytic degradation of Methyl orange experiments, the optimized Ag/AgCl/BiOCl sample prepared by photoreduction with 40 min exhibits the excellent photocatalytic performance. Under visible-light irradiation for 60 min, degradation rate of Methyl orange reaches 97%, which is 9.7, 6.1 and 4.6 times higher than that of AgCl, Ag/BiOCl and BiOCl, respectively. The UV–vis diffuse reflectance and Photoluminescence spectra of the Ag/AgCl/BiOCl photocatalyst verify that the enhanced photocatalytic activity is ascribed to its extended absorption range to visible-light region and the efficient separation efficiency of photogenerated carriers. In addition, the radical trapping experiment demonstrates that photogenerated hole and superoxide radicals play critical roles in the methyl orange degradation. The corresponding photocatalytic degradation mechanism is proposed that the excellent photocatalytic activity is attributed to the surface plasmon resonance effect of metallic Ag and heterojunction structure of Ag/AgCl/BiOCl photocatalysts. [ABSTRACT FROM AUTHOR]

Plastics and other polymer-based compounds are inevitable in our day-to-day life starting from packaging to consumer goods. Awareness about recycling plastics is all known; however, it is not sufficient to contain their negative effects on the environment and health. Disintegration products of plastic called micro- and nano-plastics (M/NPs) are increasingly found in food and environmental samples, which are considered to be an invisible threat with greater impact. Yet, there are no comprehensive regulations to monitor the M/NPs in food and water samples. Considering their harmful effects, there is a need for appropriate detection techniques to effectively identify and quantify the M/NPs in food and environment. Conventional techniques such as the Fourier transform infrared spectroscopy, Raman spectroscopy and scanning electron microscopy are expensive, require lab and labor, and are not suitable for on-field real-time monitoring. Optical detection techniques using various probes and sensors have been extensively used in the fields of bioimaging, biosensing, molecular fingerprinting etc. Recent research suggests that these probes and sensors are effective in detecting and quantifying the M/NPs. In this regard, the distinctive features of visual, colorimetric and plasmonic detection techniques have proved their high-end applicability. Most of these detectors are based on the principles of fluorescence, localized surface plasmon resonance, colorimetry, surface-enhanced Raman spectroscopy and speckle pattern analysis. This review discusses the recent advancements in the field of optical detection for M/NPs, summarizing its advantages, salient features, drawbacks, and ideas for future research. [ABSTRACT FROM AUTHOR]

Copper is relatively low cost and highly abundant compared with the well-studied noble metals such as gold and silver. However, the poor plasmonic and high susceptibility towards oxidation limit the study of its optical properties and applications as well. Herein, copper nanoparticles@polycarbonate (Cu@PC) composites were prepared by using a facile one-step solvothermal method. The Cu@PC composites have strong localized surface plasmon resonances (LSPR) due to that the PC shell can induce the particles to form many-particles system with different particle numbers, which not only lead to overlap and hybridize of the LSPR modes, but also shift the LSPR away from the interband transitions, and the PC layer also prevents the oxidation of Cu nanoparticles. The photothermal conversion efficiency of Cu@PC composites reaches 41.1% under 808 nm continuous wave (CW) laser irradiation which is higher than previously reported Cu nanomaterials that have been reported. Meanwhile, the composites also have high photothermal stability. Moreover, interfacial evaporator is prepared by assembling the Cu@PC composites on scouring sponge as light absorption layer which has > 92.8% absorption in entire solar spectrum range. Its seawater evaporation rate is 3.177 kg·m−2·h−1 with a Eevaporator/Ewater of 5.2. The high evaporation rate interfacial evaporator with low cost, simple, and scalable approach shows great application value in the field of photothermal evaporation. [ABSTRACT FROM AUTHOR]

Objective: To explore the potential mechanism of lysionotin in treating glioma. Methods: First, target prediction based on Bernoulli Naïve Bayes profiling and pathway enrichment was used to predict the biological activity of lysionotin. The binding between 5-lipoxygenase (5-LO) and lysionotin was detected by surface plasmon resonance (SPR) and molecular docking, and the inhibitory effects of lysionotin on 5-LO and proliferation of glioma were determined using enzyme inhibition assay in vitro and cell viability analysis, respectively. Furthermore, the pharmaceutical effect of lysionotin was explored by cell survival rate analysis and liquid chromatography with tandem mass spectrometry (LC-MS/MS). The protein expression, intracellular calcium ion concentration and cytoskeleton detection were revealed by Western blot, flow cytometry and fluorescence labeling, respectively. Results: Target prediction and pathway enrichment revealed that lysionotin inhibited 5-LO, a key enzyme involved in the arachidonic acid metabolism pathway, to inhibit the proliferation of glioma. Molecular docking results demonstrated that 5-LO can be binding to lysionotin through hydrogen bonds, forming bonds with His600, Gln557, Asn554, and His372. SPR analysis further confirmed the interaction between 5-LO and lysionotin. Furthermore, enzyme inhibition assay in vitro and cell survival rate analysis revealed that 50% inhibition concentration of lysionotin and the median effective concentration of lysionotin were 90 and 16.58 µmol/L, respectively, and the results of LC-MS/MS showed that lysionotin inhibited the production of 5S-hydroperoxy-eicosatetraenoic acid (P<0.05), and moreover, the LC-MS/MS results indicated that lysionotin can enter glioma cells well (P<0.01) and inhibit their proliferation. Western blot analysis demonstrated that lysionotin can inhibit the expression of 5-LO (P<0.05) and downstream leukotriene B4 receptor (P<0.01). In addition, the results showed that lysionotin affected intracellular calcium ion concentration by inhibiting 5-LO to affect the cytoskeleton, as determined by flow cytometry and fluorescence labeling. Conclusion: Lysionotin binds to 5-LO could suppress glioma by inhibiting arachiodonic acid metabolism pathway. [ABSTRACT FROM AUTHOR]

GPIHBP1 is a membrane protein of endothelial cells that transports lipoprotein lipase (LPL), the key enzyme in plasma triglyceride metabolism, from the interstitial space to its site of action on the capillary lumen. An intrinsically disordered highly negatively charged N-terminal domain of GPIHBP1 contributes to the interaction with LPL. In this work, we investigated whether the plethora of heparin-binding proteins with positively charged regions found in human plasma affect this interaction. We also wanted to know whether the role of the N-terminal domain is purely non-specific and supportive for the interaction between LPL and full-length GPIHBP1, or whether it participates in the specific recognition mechanism. Using surface plasmon resonance, affinity chromatography, and FRET, we were unable to identify any plasma component, besides LPL, that bound the N-terminus with detectable affinity or affected its interaction with LPL. By examining different synthetic peptides, we show that the high affinity of the LPL/N-terminal domain interaction is ensured by at least ten negatively charged residues, among which at least six must sequentially arranged. We conclude that the association of LPL with the N-terminal domain of GPIHBP1 is highly specific and human plasma does not contain components that significantly affect this complex. [ABSTRACT FROM AUTHOR]

Fiber optic localized surface plasmon resonance (LSPR) sensors have become an effective tool in refractive index (RI) detection for biomedical applications because of their high sensitivity. However, using conventional optical fiber has caused limitations in implanting the sensor in the body. This research presents the design and construction of a new type of polymer-based LSPR sensors to address this issue. Also, finite element method (FEM) is used to design the sensor and test it theoretically. The proposed polymer optical fiber (POF) based on citrate is biocompatible, flexible, and degradable, with a rate of 22% and 27 over 12 days. The step RI structure utilizes two polymers for light transmission: poly (octamethylene maleate citrate) (POMC) as the core and poly (octamethylene citrate) (POC) as the cladding. The POF core and cladding diameters and lengths are 700 µm, 1400 µm, and 7 cm, respectively. The coupling efficiency of light to the POF was enhanced using a microsphere fiber optic tip. The obtained results show that the light coupling efficiency increased to 77.8%. Plasma surface treatment was used to immobilize gold nanoparticles (AuNPs) on the tip of the POF, as a LSPR-POF sensor. Adsorption kinetics was measured based on the pseudo-first-order model to determine the efficiency of immobilizing AuNPs, in which the adsorption rate constant (k) was obtained be 8.6 × 10–3 min−1. The RI sensitivity of the sensor in the range from 1.3332 to 1.3604 RIU was obtained as 7778%/RIU, and the sensitivity was enhanced ~ 5 times to the previous RI POF sensors. These results are in good agreement with theory and computer simulation. It promises a highly sensitive and label-free detection biosensor for point-of-care applications such as neurosciences. [ABSTRACT FROM AUTHOR]

This work presents a comprehensive investigation into the development and characterization of novel nanocomposites composed of chitosan (Cs) and polyvinyl alcohol (PVA) with zinc oxide (ZnO) nanorods (NRs). The study begins with the successful synthesis of ZnO nanorods via the sol–gel technique with an average diameter of approximately 35 nm, as indicated by TEM image and histogram. These ZnO NRs were then seamlessly integrated into Cs/PVA polymer blend-based nanocomposite films through a casting process. The results reveal a series of noteworthy findings, where XRD patterns indicate an increase in intermolecular interactions, leading to softening of the Cs/PVA blend's polymer chain backbone and disruption of crystalline regions. Complex interactions between ZnO NRs and functional groups within the Cs/PVA matrix are also evident from FTIR analysis, where the spectra show noticeable changes in the intensity and broadness of certain peaks when ZnO NRs concentrations increase. The optical feature are investigated by ultraviolet–visible tecnique (UV–Vis), where the surface plasmon resonance peak of ZnO NRs were observed and the optical energy gap were determined. Furthermore, thermogravimetric analysis (TGA) demonstrates improved thermal stability, owing to blend-NRs interactions that safeguard the structural integrity of Cs/PVA during exposure to elevated temperatures. DC electrical conductivity significantly increases with rising temperature and NRs content. The DC conductivity value of Cs/PVA blend filled with 12 wt% ZnO NRs at 373 K reached 3.39 × 10−9 S/cm, which increased by more than two orders of magnitude due to increased nanofiller bridging the gaps between localized states, and reducing potential barrier separation and facilitating charge carrier transfer. Furthermore, these nanocomposites exhibit enhanced antibacterial activity, with increased ZnO content correlating with elevated antimicrobial efficacy. These properties make the nanocomposites highly promising for potential in optoelectronic devices where their optical and electrical characteristics can be leveraged. Simultaneously, their demonstrated antibacterial properties make them appealing for applications in food and medical packaging, safeguarding product hygiene and safety. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance (SPR) sensors are based on photon-excited surface charge density oscillations confined at metal-dielectric interfaces, which makes them highly sensitive to biological or chemical molecular bindings to functional metallic surfaces. Metal nanostructures further concentrate surface plasmons into a smaller area than the diffraction limit, thus strengthening photon-sample interactions. However, plasmonic sensors based on intensity detection provide limited resolution with long acquisition time owing to their high vulnerability to environmental and instrumental noises. Here, we demonstrate fast and precise detection of noble gas dynamics at single molecular resolution via frequency-comb-referenced plasmonic phase spectroscopy. The photon-sample interaction was enhanced by a factor of 3,852 than the physical sample thickness owing to plasmon resonance and thermophoresis-assisted optical confinement effects. By utilizing a sharp plasmonic phase slope and a high heterodyne information carrier, a small atomic-density modulation was clearly resolved at 5 Hz with a resolution of 0.06 Ar atoms per nano-hole (in 10–11 RIU) in Allan deviation at 0.2 s; a faster motion up to 200 Hz was clearly resolved. This fast and precise sensing technique can enable the in-depth analysis of fast fluid dynamics with the utmost resolution for a better understanding of biomedical, chemical, and physical events and interactions. [ABSTRACT FROM AUTHOR]

The purpose of this study was biogenic synthesis of silver nanoparticles using aqueous leaf extract of Cissus woodrowii (CW-AgNPs) and exploration of their role in inhibition cell proliferation of breast cancer cells. Inhibitory effect of biogenic CW-AgNPs on cell proliferation of MCF-7 cells was determined by MTT assay. Apoptotic cell death was demonstrated by caspase-3 assay, DNA fragmentation assay, Annexin-V-FITC/PI staining assay and cell cycle arrest assay by flow cytometry. Expression of apoptosis-related genes including caspase-3, p53 and Bcl2 was studied by western blot analysis and semi-quantitative RT-PCR. Results of UV–Vis spectrum of colloidal solution of CW-AgNPs showed surface plasmon resonance peak at 430 nm. TEM and XRD results confirmed spherical shaped, 20–30 nm sized nanoparticles. Cell proliferation results showed inhibitory effects of CW-AgNPs on MCF-7 with IC50 (24 h) 8.48 µg/mL and (48 h) 7.11 µg/mL. The CW-AgNPs altered cell morphology of MCF-7 cells and induced apoptosis significantly which was evidenced through caspase-3 activation and nuclear DNA fragmentation. The results were supported by the observation of Annexin-V-FITC/PI staining and cell cycle arrest assays. The up-regulated expression of both p53 and caspase-3 genes and down-regulation of Bcl2 at both protein and mRNA level supported their role in induction of apoptosis in MCF-7 cells in response to CW-AgNPs. The findings obtained in current study supported the role of biogenic CW-AgNPs in inhibition of cell proliferation in breast cancer cells through induction of apoptosis. [ABSTRACT FROM AUTHOR]

Metal nanomaterials have emerged as compelling candidates for ultrafast photonics applications, owing to their outstanding saturable absorption properties induced by surface plasmon resonance effects. In recent years, the exploration of saturable absorbers has encompassed noble to non-noble metals as well as diverse structures such as clusters, nanowires and nanoplates. Herein, we comprehensively elucidate the operational principles of metal nanomaterials in ultrafast lasers, including the surface plasmon resonance effect and their complex optical properties. Furthermore, recent advancements in metal nanomaterials utilized in ultrafast lasers have been systematically summarized and classified according to the dimensional structure that profoundly affects their properties. Moreover, the operating parameters of saturable absorbers based on metal nanomaterials are listed in detail. Finally, we look ahead to further directions of metal nanomaterials in ultrafast photonics, presenting explorations in metasurfaces, potential alternatives, and novel integration methods. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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]

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]

In this study, a novel dual-core photonic crystal fiber sensor based on surface plasmon resonance is proposed for cancer detection in various parts of the human body. The proposed sensor is designed with a simplified circular geometrical structure with two different sizes of air holes. A gold thin film is placed on the on the cladding of the photonic crystal fiber. The performance of the proposed sensor is demonstrated by applying full vectorial finite element method. The confinement loss and amplitude sensitivity are calculated for the different normal and cancer cells. The proposed sensor has the amplitude sensitivity 595 RIU−1 for the skin cancer and wavelength sensitivity 16,285 nm/RIU for the Adrenal Gland cancer. Furthermore, the proposed cancer sensor achieved the highest Figure of Merit of 571.4 RIU−1. The numerical results indicate that the suggested biosensor could detect cancer cells. Finally, we investigate the fabrication tolerance on the confinement loss and amplitude sensitivity. [ABSTRACT FROM AUTHOR]