Plasmon Resonance Research Articles

Potential antiviral activity of rhamnocitrin against influenza virus H3N2 by inhibiting cGAS/STING pathway in vitro.

Influenza remains a serious issue for public health and it's urgent to discover more effected drugs against influenza virus. Rhamnocitrin, as a flavonoid, its effect on influenza virus infection remains poorly explored. In this study, rhamnocitrin showed antiviral effect and anti-apoptosis on influenza virus A/Aichi/2/1968 (H3N2) in MDCK cells and A549 cells. In addition, molecular docking revealed that rhamnocitrin have good binding activity with the target proteins cGAS and STING, molecular dynamic simulation and surface plasmon resonance showed that rhamnocitrin could form a stable complex with the above proteins. Moreover, the qPCR and western blot assays further verified that rhamnocitrin could reduce type I IFN and proinflammatory cytokines production by inhibiting the cGAS/STING pathway. Taken together, the results suggest that rhamnocitrin could be a potential anti-viral agent against influenza.

Comparison of retinol binding protein 1 with cone specific G-protein as putative effector molecules in cryptochrome signalling.

Vision and magnetoreception in navigating songbirds are strongly connected as recent findings link a light dependent radical-pair mechanism in cryptochrome proteins to signalling pathways in cone photoreceptor cells. A previous yeast-two-hybrid screening approach identified six putative candidate proteins showing binding to cryptochrome type 4a. So far, only the interaction of the cone specific G-protein transducin α-subunit was investigated in more detail. In the present study, we compare the binding features of the G-protein α-subunit with those of another candidate from the yeast-two-hybrid screen, cellular retinol binding protein. Purified recombinant European robin retinol binding protein bound retinol with high affinity, displaying an EC50 of less than 5nM, thereby demonstrating its functional state. We applied surface plasmon resonance and a Förster resonance transfer analysis to test for interactions between retinol binding protein and cryptochrome 4a. In the absence of retinol, we observed no robust binding events, which contrasts the strong interaction we observed between cryptochrome 4a and the G-protein α-subunit. We conclude that retinol binding protein is unlikely to be involved in the primary magnetosensory signalling cascade.

Dual-Channel High-Sensitivity Temperature and Magnetic Field Sensor Based on Mach–Zehnder Interference and Surface Plasmon Resonance

Dual-Channel High-Sensitivity Temperature and Magnetic Field Sensor Based on Mach–Zehnder Interference and Surface Plasmon Resonance

Graphene/black phosphorus-based infrared metasurface absorbers with van der Waals Schottky junctions

Black phosphorus (BP) is a promising candidate for fabricating infrared (IR) photodetectors because its bandgap in the IR region can be controlled by varying the number of layers. BP-based metasurfaces have attracted considerable attention for applications in wavelength-selective and/or polarization-selective IR absorbers. Graphene and BP (Gr/BP) van der Waals (vdW) heterostructures are expected to enhance the performance of BP-based IR photodetectors. However, the Gr/BP vdW heterostructure forms a Schottky junction; thus, the electron transfer between Gr and BP should be investigated to determine the precise optical properties of Gr/BP vdW heterostructure-based metasurfaces. In this study, the electron transfer in the Gr/BP vdW heterostructure is investigated theoretically. The metasurface absorber structure proposed based on the results comprises periodic Gr/BP vdW heterostructure strips on top, a middle dielectric layer, and a bottom reflector. Numerical calculations indicated that the Gr/BP vdW heterostructure has strong wavelength- and polarization-selective near-unity IR absorption. The absorbance is increased and absorption wavelength is shortened compared with those of the monolayer-BP-based metasurface. The absorption wavelength can be controlled by changing the width of the Gr/BP strips owing to the hybrid localized surface plasmons of Gr/BP. This is attributed to the electron transfer through the Schottky junction between Gr and BP with enhanced localized surface plasmon resonance. The results suggest that the Gr/BP vdW heterostructure is a promising platform for realizing wavelength-selective and/or polarization-selective IR photodetectors and IR absorbers/emitters. The resulting photodetectors exhibit high responsivity and low noise because the BP bandgap corresponds to the IR wavelength region.

Stress biomarker detection with a grating-coupled surface plasmon resonance sensor

Stress biomarker detection with a grating-coupled surface plasmon resonance sensor

Inducing exceptional points, enhancing plasmon quality and creating correlated plasmon states with modulated Floquet parametric driving.

The control of low frequency collective modes in solids by light presents important challenges and opportunities for condensed matter physics. We propose a method to parametricallydrive low THz range collective modes in an interacting many body system using Floquet driving at optical frequencies with a modulated amplitude. We demonstrate that it can be used to design plasmonic time-varying media with singular dispersions. Plasmons near resonance with half the modulation frequency exhibit two lines of exceptional points connected by dispersionless states. Above a critical driving strength, resonant plasmon modes become unstable and undergo a continuous transition towards a crystal-like structure stabilized by interactions and nonlinearities. This new state breaks the discrete time translational symmetry of the drive as well as the translational and rotational spatial symmetries of the system and exhibits soft, Goldstone-like phononic excitations. Below the instability threshold, our method can be used to enhance the quality of plasmon resonances.

Angle insensitive filters based on Fabry–Pérot resonance structures

Filters based on plasmon resonance suffer from low efficiency due to inevitable metal loss. Moreover, their operational limitations, particularly their inability to function effectively at large incident angles, significantly restrict their practical applications. To address these challenges, we propose an all-dielectric filter characterized by relatively small Ohmic loss and remarkably high efficiency, even at wide incident angles. The filter is based on Fabry–Pérot cavity resonance, with narrow bandwidth and high transmittance. The transmittance in the near-infrared band is as high as 99%, and the transmittance in the shortwave band is highly suppressed. This filter offers ease of manufacture coupled with exceptional efficiency. It is expected to gain application prospects in different fields such as liquid crystal displays, optical communications, sensor detection, and imaging.

Abstract B005: A robust NSCLC biomarker: miR-7-5p: in-silico validation and potential SPR- based probe for detection

Abstract The abundance of micro RNAs as a specific biomarker for accurately detecting cancer metastasis has arisen recently. The expression levels of miRNA are analyzed to get insights into cancer tissue detection and subtypes. Similar to other cancer types, the miRNA shows high levels of target mRNA dysregulation in association with non-small cell lung carcinoma (NSCLC). Among many promising cancer biomarkers for NSCLC, miR-7-5p has shown significant downregulation in the NSCLC tissues and targets proto-oncogenes like PAK2 and NOVA2. The expression levels of different proto-oncogenes targeting the miR-7-5p in NSCLC show that the EGFR- mutated NSCLC has an experimental validation. And, the target validation of the miR-7-5p could be analyzed using SPR (Surface plasmon resonance) based sensors at a single nanoparticle level such as Au nanocube due to its high specificity and accountability. Despite being an accountable tool for cancer diagnosis, miRNA-based biomarkers sometimes cause poor diagnostic specificity and reproducibility due to their heterogenicity and immunogenicity in cancer detection. To overcome these shortcomings, the biomarkers need to be validated according to recent clinical studies. Citation Format: Chandrajeet Dhara, Anindita Dhara, Saumyatika Gantayat. A robust NSCLC biomarker: miR-7-5p: in-silico validation and potential SPR- based probe for detection [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr B005.

Immuno-PET/CT Imaging of Trop2 with [18F]AlF-RESCA-T4 Differentiates Lung Cancer from Inflammation.

Immuno-PET/CT imaging, a branch of molecular imaging, can noninvasively and specifically visualize biomarker expression across the body. Trophoblast cell surface antigen 2 (Trop2) is a pan-cancer biomarker and plays a crucial role in tumorigenesis through multiple signaling pathways. The study aims to develop and translate novel Trop2 single-domain antibody (sdAb) tracers for clinical use. Methods: Two sdAbs (i.e., His-tagged T4 and His-tag-free RT4) are recombinantly expressed in Chinese hamster ovary cells. The purities and binding kinetics are determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis, high-performance liquid chromatography, and surface plasmon resonance assays. The AlF restrained complexing agent (RESCA) method is applied to develop 18F-labeled sdAb tracers ([18F]AlF-RESCA-T4 and [18F]AlF-RESCA-RT4), followed by thorough preclinical imaging and blocking studies on tumor-bearing mice and a pilot clinical trial evaluating the clinical imaging safety and feasibility of [18F]AlF-RESCA-T4 immuno-PET/CT. Results: [18F]AlF-RESCA-T4 and [18F]AlF-RESCA-RT4 possess high radiochemical purities. Preclinical imaging in the T3M-4 tumor model revealed prominent uptake (percentage injected dose/g) of [18F]AlF-RESCA-T4 (11.13 ± 1.53, n = 4) and [18F]AlF-RESCA-RT4 (8.83 ± 1.22, n = 4), which were significantly reduced by coinjection of unlabeled T4 and RT4 in blocking studies. The His-tag removal strategy further optimized the probe's invivo pharmacokinetics and reduced renal radioactivity accumulation without significantly decreasing tumor uptake. In a pilot clinical trial, [18F]AlF-RESCA-T4 immuno-PET/CT showed promising potency in annotating Trop2 expression and differentiating tumors from inflammatory diseases such as tuberculosis. Conclusion: [18F]AlF-RESCA-T4 and [18F]AlF-RESCA-RT4 can specifically annotate Trop2 expression. Clinical [18F]AlF-RESCA-T4 immuno-PET/CT imaging can screen patients for Trop2-targeted therapies and differentiate lung inflammation from cancer.

Reducing the effective dose of doxycycline using chitosan silver nanocomposite as a carriers on gram positive and gram-negative bacteria.

Doxycycline (Doxy) is a tetracycline antibiotic with a potent antibacterial activity against a broad range of bacteria. Using nanotechnology is one feasible way to increase the antibiotics' ability to penetrate the body and increase their antibacterial effectiveness. In this work, we report the formation of a stable green synthesized silver nanoparticles (AgNPs) by chitosan with Doxy nanocomposite for the first time. The obtained nanoparticles were characterized by transmission electron microscopy (TEM), zeta-potential, UV-Visible spectroscopy and four transform infrared spectroscopy (FTIRs). The antibacterial effect of doxy, AgNPs and doxy/AgNPs were determined on Gram-positive Staphylococcus aureus, Streptococcus mutans and Gram-negative Escherichia coli, Klebsiella pneumonia. This combined therapeutic agent restored the susceptibility of doxy and showed an antibacterial activity against tested bacteria. AgNPs has absorption peak at 445nm, mixing of Doxy with AgNPs causes all doxy absorptions to red shift and a broadening in surface plasmon resonance (SPR) for AgNPs and show a slight increase in particle size of AgNPs from 12 ± 2nm to 14 ± 2nm with high stability as zeta potential was 29 mv and 48.5mv for AgNPs and Doxy/AgNPs respectively. The antibacterial effect of Doxy/AgNPs nanocomposite was found to be twice effect of free doxy, suggesting a synergistic interaction between the two components. In conclusion, synergy of doxy with AgNPs is quite promising for antibiotic resistant strains. These results highlight the ability of AgNPs to boost the efficacy of the doxycycline.

Novel Inhibitory Actions of Neuroactive Steroid [3α,5α]-3-Hydroxypregnan-20-One on Toll-like Receptor 4-Dependent Neuroimmune Signaling

The endogenous neurosteroid (3α,5α)-3-hydroxypregnan-20-one (3α,5α-THP) modulates inflammatory and neuroinflammatory signaling through toll-like receptors (TLRs) in human and mouse macrophages, human blood cells and alcohol-preferring (P) rat brains. Although it is recognized that 3α,5α-THP inhibits TLR4 activation by blocking interactions with MD2 and MyD88, the comprehensive molecular mechanisms remain to be elucidated. This study explores additional TLR4 activation sites, including TIRAP binding to MyD88, which is pivotal for MyD88 myddosome formation, as well as LPS interactions with the TLR4:MD2 complex. Both male and female P rats (n = 8/group) received intraperitoneal administration of 3α,5α-THP (15 mg/kg; 30 min) or a vehicle control, and their hippocampi were analyzed using immunoprecipitation and immunoblotting techniques. 3α,5α-THP significantly reduces the levels of inflammatory mediators IL-1β and HMGB1, confirming its anti-inflammatory actions. We found that MyD88 binds to TLR4, IRAK4, IRAK1, and TIRAP. Notably, 3α,5α-THP significantly reduces MyD88-TIRAP binding (Males: −31 ± 9%, t-test, p < 0.005; Females: −53 ± 15%, t-test, p < 0.005), without altering MyD88 interactions with IRAK4 or IRAK1, or the baseline expression of these proteins. Additionally, molecular docking and molecular dynamic analysis revealed 3α,5α-THP binding sites on the TLR4:MD2 complex, targeting a hydrophobic pocket of MD2 usually occupied by Lipid A of LPS. Surface plasmon resonance (SPR) assays validated that 3α,5α-THP disrupts MD2 binding of Lipid A (Kd = 4.36 ± 5.7 μM) with an inhibition constant (Ki) of 4.5 ± 1.65 nM. These findings indicate that 3α,5α-THP inhibition of inflammatory mediator production involves blocking critical protein-lipid and protein-protein interactions at key sites of TLR4 activation, shedding light on its mechanisms of action and underscoring its therapeutic potential against TLR4-driven inflammation.

Phage Display Against 2D Metal-Organic Nanosheets as a New Route to Highly Selective Biomolecular Recognition Surfaces.

Peptides are important biomarkers for various diseases, however distinguishing specific amino-acid sequences using artificial receptors remains a major challenge in biomedical sensing. This study introduces a new approach for creating highly selective recognition surfaces using phage display biopanning against metal-organic nanosheets (MONs). Three MONs (ZIF-7, ZIF-7-NH2, and Hf-BTB-NH2) are added to a solution containing every possible combination of seven-residue peptides attached to bacteriophage hosts. The highest affinity peptides for each MON are isolated through successive bio-panning rounds. Comparison of the surface properties of the MONs and high-affinity peptides provide useful insights into the relative importance of electrostatic, hydrophobic, and co-ordination bonding interactions in each system, aiding the design of future MONs. Coating of the Hf-BTB-NH2 MONs onto a quartz crystal microbalance (QCM) produced a five-fold higher signal for phage with the on-target peptide sequence compared to those with generic sequences. Surface plasmon resonance (SPR) studies produce a 4600-fold higher equilibrium dissociation constant (KD) for on-target sequences and are comparable to those of antibodies (KD = 4 x 10-10m). It is anticipated that insights from the biopanning approach, combined with the highly tunable nature of MONs, will lead to a new generation of highly selective recognition surfaces for use in biomedical sensors.

Perspectives of Fluctuation-Enhanced Gas Sensing by Two-Dimensional Materials

We present the results of gas sensing using the fluctuation-enhanced sensing method in selected two-dimensional materials (2DMs). We claim that gas sensing selectivity can be improved further by considering semiconducting two-dimensional materials doped by noble metal nanoparticles. The 2DMs’ structures exhibit some imperfections defined by their structure, occurring repeatedly there. These imperfections are adsorption–desorption centers responsible for gas-sensing properties and generating flicker noise of various intensities. We consider how these imperfections can be modulated and utilized for fluctuations-enhanced gas sensing. We propose the decoration of 2DMs by noble metal nanoparticles that impact flicker noise. Additionally, we consider utilizing localized surface plasmonic resonance induced by irradiation at selected wavelengths.

Green Synthesis of Silver Nanoparticles Using Doxycycline: Evaluation of Antimicrobial Potential and Organ-specific Toxicity

Silver nanoparticles (Ag-NPs) have wide applicability as antimicrobial, biomedical, and anti-cancer drug delivery systems. This study aimed to synthesize Ag-NPs using green methodology to assess their antimicrobial properties and toxicity. Ag-NPs were prepared using doxycycline, an antibiotic serving as a reducing and capping agent. The synthesized Ag-NPs were characterized by ultraviolet-visible spectrophotometry, X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectrometry. The antimicrobial efficacy of doxycycline-mediated Ag-NPs was assessed on Candida species in vitro and for toxicity in male albino mice in vivo. The Ag-NPs showed a surface plasmon resonance at 411 nm, indicating a 90 nm average size and spherical shape. Toxicity was tested on mouse organs (liver, kidney, spleen, heart and stomach) using three Ag-NP doses (50, 100, 200 mg/kg) over 14 days. The synthesized Ag-NPs produced large inhibition zones against two well-known fungal species, C. albicans and C. tropicalis, demonstrating their antimicrobial potential. The Ag-NPs showed varying degrees of toxicity in different mouse organs, depending on the administered dose, with more pronounced adverse effects observed at higher concentrations. Periodic administration of Ag-NPs at low-dose volumes holds promise as a safe approach to their use as antimicrobial agents. Low-dose Ag-NPs are minimally toxic and show strong antimicrobial efficacy.

Investigation of Symmetrical Long Range Surface Plasmon Resonance Structure Using Induced Transmission Model

Investigation of Symmetrical Long Range Surface Plasmon Resonance Structure Using Induced Transmission Model

Single-Molecule Detection of Serum MicroRNAs for Medulloblastoma with Biphasic Sandwich Hybridization-Assisted Plasmonic Resonant Scattering Imaging.

MicroRNA (miRNA) dysregulation is closely related to the occurrence and progression of medulloblastoma (MB). However, the full potential of serum circulating miRNAs in MB diagnosis is restricted by their ultralow abundance in peripheral blood due to blood-brain barrier. Here, we report the direct preamplification-free detection of aberrant expression of oncogenic miRNAs in serum from MB patients by proposing a simple yet robust single-molecule assay that combines biphasic sandwich hybridization in nucleic acids and the dark-field single-particle plasmonic imaging (B2S2PI). In this strategy, signal DNA was prehybridized with target miRNA in homogeneous solution to form sDNA-RNA complexes. Then the captured DNA strands with rationally adjusted surface densities could efficiently capture the sDNA-RNA complexes to generate a well-separated DNA-RNA sandwich structure. The combination of homogeneous and heterogeneous reactions enabled interface-mediated hybridization reactions to maintain molecular stability with fewer bases, making it suitable for the direct amplification-free assays of short miRNA targets. Labeling the DNA-RNA hybrids with plasmatic gold nanotags allowed nondestructive recognition and imaging of individual miRNA targets under mild conditions with high signal-to-noise ratio. By digitally counting and analyzing the bright plasmonic resonant scattering spots, B2S2PI enabled both the measurement of a low femtomolar concentration of circulating miRNA-21 in 5 μL sample volume within a turnaround of 2 h and the discrimination of single base mismatches. Moreover, B2S2PI was universal for detecting miRNAs with different sequences and secondary structures. Further analysis of clinical serum samples revealed that B2S2PI was capable of accurately distinguishing MB patients from noncancer controls with an area under the curve (AUC) of 0.99, which was superior to that of qRT-PCR. B2S2PI holds promise as a novel alternative means for single-molecule miRNA assay and sheds light on the circulating nucleic acid-based liquid biopsy of intracranial malignant tumors.

Defect-insensitive cylindrical surface lattice resonance array and its batch replication for enhanced immunoassay.

Surface lattice resonances (SLR) have been demonstrated to enhance the sensitivity and reduce the full width at half maximum (FWHM) of the plasmonic resonances. However, their widespread application in immunoassays has been hindered by limitations of high structural defect sensitivity and fabrication costs. Here, we design a novel three-layer cylindrical SLR array that exhibits high tolerance against structural defects, which would facilitate straightforward fabrication. By integrating metal evaporation and nanoimprint lithography, we demonstrate the replication of the SLR array with exceptional quality. Theoretical simulations indicate that the resonance dips of these arrays exhibit are not sensitive to various structural defects. The experimental results reveal that the FWHM of these arrays can be as low as 5.1 nm while maintaining robust resonance characteristics. Furthermore, we demonstrated the high spectral sensitivity of the SLR array, which enabled the detection of immunoglobulin G (IgG) at concentrations as low as 609 pg/mL. These findings emphasize the potential of the defect-insensitive SLR array as a highly scalable immunoassay platform with exceptional performance.

Abstract 4118993: β1 Adrenergic Receptor Autoantibodies Promote Heart Failure Though Activation of Prostaglandin E2 Receptor EP1/Phosphodiesterase 4B Pathway

Background: β1 adrenergic receptor (β1-AR) autoantibodies (β1-AA) can cause heart failure (HF) through activating of β1-AR; However, β-AR antagonists cannot completely reverse the cardiac injury induced by β1-AA and improve the survival rate of patients with β1-AA-positive HF. However, the β1-AR-independent mechanisms of heart failure induced by β1-AA are unclear. Methods: Proteomics of mice hearts was used to identify the specific changed proteins induced by β1-AA. The expression of phosphodiesterase 4B (PDE4B) was detected by western blot in neonatal mice mouse cardiomyocytes (NMCMs) and heart tissues. The binding proteins with β1-AA were enriched by immunoprecipitation (IP) and identified by mass spectrum. The interaction between β1-AA and prostaglandin E2 Receptor EP1 was detected by co-IP and surface plasmon resonance. The cardiac function and cardiac remodeling of PDE4B transgenic (TG) mice and EP1 knockout (KO) mice. Results: Firstly, PDE4B was changed the most proteins induced by β1-AA compared to β1 adrenergic receptor dobutamine. Moreover, the decrease of PDE4B induced by β1-AA cannot be reversed by metoprolol in vivo and in vitro. Secondly, the cAMP/PKA pathway and cardiac injury/dysfunction induced by β1-AA were inhibited after activation of PDE4B or PDE4B-TG in vivo and in vitro. Thirdly, β1-AA can bind with EP1 and activate Gq/IP3 pathway. The activation effect was abolished by EP1 antagonist. Lastly, blocked EP1 or EP1-KO will reverse the decreased PDE4B and cardiac injury/dysfunction induced by β1-AA. Conclusions: Our work reveals that β1-AA can activate of EP1/PDE4B pathway to result in heart failure.

Eco-Conscious Approach to Synthesizing Aluminum Oxides Using Nonthermal Plasma Technology

AlO is a prevalent oxide compound composed of aluminum and oxygen, with the chemical formula Al2O3. This study aims to prepare aluminum oxide nanoparticles using aluminum nitrate nonahydrate Al(NO[Formula: see text] 9H2O through direct exposure to a plasma jet system using argon gas, as plasma is the fourth state of matter and a common effective method. The major study in the preparation of Al2O3 nanoparticles, which is a physical method, examines the effect of aluminum oxide nanoparticles against bacteria and fungi. Different methods were used for diagnosis. The X-ray diffraction examination showed an average particle size of 37.8 nm. It was also found through the UV-Vis examination that a surface plasmon resonance was formed at 300 nm with an energy gap value of 4.21 eV. The electron microscope field emission scanning (FE-SEM) was used to study the surface morphology. The results of biological testing showed that aluminum oxide nanoparticles have high antibacterial and antifungal activity.

A CW-Pumped Dye Nanolaser With an Optimized Nanocavity.

Plasmonic nanolasers, which are promising coherent light sources for integrated photonics, super-resolution imaging, and ultrasensitive sensing applications, face the challenge of high thresholds due to inherent losses in plasmonic nanocavities. While considerable efforts have been made to improve the Q factor, typically quantified by the full width at half maximum (FWHM), intensity (ΔI) is another critical feature of plasmonic resonance. However, the combined influence of both the Q factor and resonance intensity of a plasmonic nanocavity on nanolasing threshold has not been sufficiently explored, as experimentally controlling one variable while keeping the other constant is challenging. Here, an ultra-low threshold plasmonic nanolaser is demonstrated by systematically optimizing the plasmonic nanocavity. By carefully controlling both the FWHMs and resonance intensities of the plasmonic resonators, a record low threshold of 2.6 µJcm-2 for a dye-based nanolaser is achieved at room temperature- an order of magnitude lower than previous records. In addition, nanolasing under continuous-wave (CW) excitation is reported at room temperature gained by the same dye molecule. The results provide new insights into the design of high-performance plasmonic nanolasers and offer a promising path toward realizing applications of nanoscale coherent light sources.