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Surface plasmon resonance (SPR) holographic microscopy exploits surface plasmon wave as illumination and acquires both SPR intensity and phase images. It detects extremely tiny variations of weakly interacting objects owing to high sensitivity and has been applied in cell biology, material science, surface chemistry, etc. However, it is very challenging to solve the problem of poor spatial resolution due to the transverse propagation of surface plasmon wave. In this paper, an azimuthal scanning excitation method is proposed in SPR holographic microscopy to improve the spatial resolution by engineering the Fourier spectra of SPR images from dual‐arc to circular shape. The study modulates the light field with spatial position, wavevector, and polarization to realize azimuthal scanning excitation of SPR. Systematic experiments of dielectric spheres, nanowires, two‐dimension materials, and complex nanostructure are conducted to show the resolution improvement with one order of magnitude, the higher detection sensitivity of SPR phase than that of SPR intensity, and the necessities of both of high‐resolution SPR intensity and phase images to retrieve sample information in certain scenarios. Benefiting from the high detection sensitivity and spatial resolution, the proposed microscopy will find wide applications in nanoparticle analysis, low‐dimensional material characterization, and imaging extremely thin or transparent samples. [ABSTRACT FROM AUTHOR]

The editorial in the journal "Bioengineering (Basel)" discusses the advancements and challenges in utilizing thermal technology in biomedical applications, particularly in cryopreservation and thermal therapy. The document highlights innovative research on cryopreservation techniques, including the use of liquid helium and natural cryoprotectants like honey. It also explores the potential of thermal technology in cancer therapy and cardiovascular interventions, emphasizing the need for further research to optimize treatments and ensure long-term biocompatibility. The integration of biology, materials science, and thermodynamics is crucial for addressing current obstacles and unlocking the full therapeutic potential of thermal engineering in clinical settings. [Extracted from the article]

More efficient excitation energy transfer is simulated for distances smaller than 5 nm, while at distances less than 1.5 nm, the opposite occurs, indicating an interplay between the excitation of the first nanoparticle and the back transfer from the second nanoparticle. In another article in this Special Issue, Herrera and Litinskaya[119] develop a macroscopic model of exciton-plasmon metamaterials composed of nanoparticle dimers with organic molecules (chromophores are considered in the paper) situated inside the gap. 155, 134117 (2021).10.1063/5.0060171 97 S. Wang, G. D. Scholes, and L.-Y. Hsu, "Quantum dynamics of a molecular emitter strongly coupled with surface plasmon polaritons: A macroscopic quantum electrodynamics approach", J. Chem. Phys. The field of plasmonics has been in the spotlight in physics,[1] materials science,[2] chemistry,[3] and biology[4] for more than a decade, with relevant applications in photovoltaics,[5] biosensing,[6] and nanoimaging.[7] Thanks to fascinating progress in nanofabrication, we now have tools to create artificial metal/dielectric interfaces with 1 nm precision,[[8]] while ultrafast optical detection techniques are now offering riveting time resolution as short as 2 fs.[10] Combined together, these tools are used to further advance our understanding of light-matter interaction at the nanoscale when the classical view collides and merges with quantum properties of matter and light.[11] The ability of plasmonic materials to sustain surface plasmon-polariton (SPP)[12] resonances results in a very small SPP mode volume. [Extracted from the article]

The quest for environmentally sustainable materials spans many fields and applications including optical materials. Here, we present the development of light filters using a gelatin-based nanocomposite. Owing to the plasmonic properties of metallic nanoparticles (NPs), strong light-matter interactions, these filters can be customized across the UV-Visible-NIR spectrum. The filters are designed for modular use, allowing for the addition or removal of desired spectral ranges. Moreover, the nanocomposites are composed of biodegradable and biocompatible materials which highlight the intersection of chemistry and ecological awareness for the exploration of new eco-friendly alternatives. These plasmonic gelatin-based filters block light due to the Localized Surface Plasmon Resonance (LSPR) of the NPs and can be tailored to meet various requirements, akin to a diner selecting options from a menu. This approach is inspired by culinary techniques, and we anticipate it will stimulate further exploration of biomaterials for applications in optics, materials science or electronics. Optical filter materials are used across scientific disciplines for imaging or spectroscopy, but inexpensive and eco-friendly alternatives remain underexplored. Here, the authors exploit the localized surface plasmon resonance of metal nanoparticles embedded in edible gelatine for modular light filters working in the ultraviolet to near-infrared range. [ABSTRACT FROM AUTHOR]

The growth of material science and technology places a high importance on the creation of better processes for the synthesis of copper nanoparticles. So that, an easy, ecological, and benign process for producing copper nanoparticles (CuNPs) has been developed using candy leaf (Stevia rebaudiana) leaves aqueous extract for the first time. UV-visible spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), Fourier transmission infrared (FTIR), and zeta potential were applied to demonstrate strong characterization for the biosynthesized stevia-CuNPs. The UV-visible absorbance at 575 nm of surface plasmon resonance (SPR) was 1.2. The particle size mean diameter was recorded as 362.3 nm with − 10.8 mV zeta potential. The HR-TEM scanning revealed 51.46–53.17 nm and spherical-shaped stevia-CuNPs surrounded by coat-shell proteins. The cytotoxicity and cytocompatibility activity assay revealed that stevia-CuNPs was safe in lower concentrations and had a significant cell viability reduction in higher concentrations. The produced stevia-CuNPs were applied as antimicrobial agents against eight pathogenic bacteria and five fungi strains. The inhibitory action of the stevia-CuNPs was more pronounced in bacteria than in fungi, and they likewise demonstrated further inhibition zones in Staphylococcus aureus (50.0 mm) than in Aspergillus flavus (55.0 mm). With inhibition zone sizes of 50.0 mm and 47.0 mm and 50 µg/ml minimum inhibitory concentration, S. aureus and A. flavus were the most inhibited pathogens. The minimum lethal effect (MLC) estimate for S. aureus was 50 µg/ml, whereas 75 µg/ml for A. flavus. The stevia-CuNPs mode of action was characterized as bactericidal/fungicidal as the ratio of MIC to MLC was estimated to be equal to or less than 2. After all, stevia-CuNPs could be used as an alternative to commercial antibiotics to solve the problem of multidrug-resistant (MDR) microorganisms. Key points: • Stevia-CuNPs in lower than 200 ug/ml concentrations are safe and tolerant for Vero normal cells. • Stevia-CuNPs has high antimicrobial activity which has a significant effect on various pathogenic bacteria. • Stevia-CuNPs has bactericidal/fungicidal mode of action for various pathogenic bacteria and fungi. [ABSTRACT FROM AUTHOR]

Due to their distinctive optical potential, controlled plasmonic features, control over size and shape, and ability to manipulate their localized surface plasmon resonance (LSPR) and their response to their surroundings, silver nanoparticle attracts special attention in the fields of the biosensor. Silver (Ag) is an appealing tool in many domains, including diagnosis, medicine delivery, environment, electronics, and as an antibacterial agent. Ag nanoparticle applications are ubiquitous today in the fields of biosensors. Numerous studies have demonstrated the effectiveness of using Ag nanoparticles to improve the specific detection of clinical indicators. The development of nanotechnology has greatly benefited the field of biosensors since nanomaterials have a high surface-to-volume ratio that enables them to operate with greater sensitivity and effectiveness. Utilizing interdisciplinary study in biology, chemistry, and material science, recent advancements in nanotechnology encouraged the manufacture of nanomaterials in a variety of shapes and sizes. In the context of disease diagnosis, this review highlighted the use of Ag nanoparticles in biosensors to detect small molecules to bigger entire cells. This paper also discusses how to make a glucose biosensor more sensitive. It describes how the detection performance of biomolecules including DNA, protein, tiny molecules, and complete cells can be improved. For future applications in the field of diagnosis, this review helps in developing an overall understanding of the clinical importance of Ag nanoparticles. These biosensors can be implemented in the field of diagnosis to speed up the response time. [ABSTRACT FROM AUTHOR]

Lichen is one of the most abundant non-vascular biomasses; however, a systematic study on the application of biomass in nanomaterial synthesis is very limited. In this study, an aqueous lichen extract was obtained from Hypotrachyna cirrhata, one of the most abundant Himalayan lichen biomasses, using a simple cold percolation method. The effects of extract-to-silver nitrate mixing ratio, pH and waiting time on the growth and stability of nanoparticles were systematically explored. The rate constant for bio-reduction was found to be 5.3 × 10−3 min−1. Transmission electron microscopy showed a narrow particle size distribution with a mean particle size of 11.1 ± 3.6 nm (n = 200). The X-ray diffraction and selected area electron diffraction techniques confirmed the formation of cubic crystals. The synthesized colloidal solution showed excellent response to Hg2+ and Cu2+ ions in spiked water samples. The limit of detection and calibration sensitivity for Hg2+ and Cu2+ ions were found to be 1 and 5 mg l−1 and 2.9 × 10−3 and 1.6 × 10−3 units ppm−1, respectively. These findings suggested that spherical silver nanoparticles with a narrow particle size distribution can be synthesized on a laboratory scale using an aqueous H. cirrhata lichen extract, and the colloidal solution can be used for the detection of selected heavy metals in water samples.

Interface phenomena refer to the phenomena caused by various physical and chemical processes occurring at phase interfaces. These phenomena can include adhesion, friction, lubrication, evaporation, condensation, adsorption, monolayer formation, and other phenomena and are applied in many fields, such as food, papermaking, rubber, material science, energy, and biomedicine. However, traditional detection equipment cannot meet the interface phenomena observation needs because the information detected by techniques such as electrochemistry, spectroscopy, chromatography, and mass spectrometry is limited, as are the sensitivity and minimum detection limit. Surface plasmon resonance (SPR) combined technology is a powerful tool for investigating interface phenomena. This paper reviews all combination technologies of SPR with various conventional detection systems, emphasizing the combination with electrochemistry, Raman spectroscopy, and mass spectrometry. These technologies can observe interface phenomena through SPR and provide redox, molecular structure, functional group change, and other information. Through this information, the reactions on the interface can be made clearer and more controllable, which plays an important role in practical detection. In the future, SPR combined technology will mainly develop toward signal enhancement, light source coupling mode, and sensor chip design, and SPR will be combined with various detection technologies to achieve real‐time in situ detection of interface phenomena. [ABSTRACT FROM AUTHOR]

10.1063/5.0020113 19 M. Ramonas, J. Liberis, A. Simukovic, E. Sermuksnis, A. Matulionis, V. Avrutin, Ü Özgür, and H. Morkoç, "Terahertz oscillations in gallium nitride quantum-well channels predicted by hot-electron noise temperature behavior at microwave frequency", J. Appl. Phys. 10.1063/5.0027108 27 S. B. Naldo, A. V. Bernotas, and B. F. Donovan, "Understanding the sensitivity of the two-temperature model for electron-phonon coupling measurements", J. Appl. Phys. Generation, lifetime, and extraction of hot electrons at the surfaces of metallic materials and plasmonic nanostructures have been extensively studied and discussed in the last 10 years. [Extracted from the article]

A novel technique using a W-band metasurface for the purpose of transmissive fine powder layer sensing is presented. The proposed technique may allow for the detection, identification, and characterization of inhomogeneous ultrafine powder layers which are effectively hundreds of times thinner than the incident wavelengths used to sense them. Such a technique may be useful during personnel screening processes (i.e., at an airport) and in industrial manufacturing environments where early detection and quantization of harmful airborne particulates can be a matter of security or safety. The proposed sensing technique was experimentally and theoretically tested. The results suggest that, using this technique, one may identify, extract the effective complex dielectric properties, and measure the layer thicknesses of ultrafine powder layers present on a metasurface. Using this technique, it may be possible to identify and characterize diverse media in various physical, chemical, and biological metasurface sensing efforts at numerous bands of the electromagnetic spectrum. [ABSTRACT FROM AUTHOR]

• An exhaustive review of prism based SPR configurations using 2D materials have been done. • The works using graphene, Black phosphorus, Maxene and their heterostructures are focused. • The data sets corresponding to dispersion relations of several materials is given. • Fundamentals of SPR, different numerical methods used for designing the effective SPR chip along with applications of 2D materials is reviewed. Increasing the demand for ultrasensitive sensors in the sensing community and significant breakthroughs in materials science have inspired and promoted the development of new-generation multi-sensing plasmonic sensors assisted by 2D materials. 2D materials have received significant attention from the research community due to their excellent properties. Their wide application in sensing is expected for environmental monitoring, medical diagnostics, and food safety. Recently, surface plasmon resonance (SPR) based sensors assisted with 2D materials such as Graphene, MoS 2 , MXenes, Black Phosphorous, Antimonene and their heterostructures, have emerged as a class of novel plasmonic sensing with their great detection sensitivity and impressive performance. In this review, we comprehensively surveyed the use of a few of the above-mentioned 2D materials for designing Prism based SPR sensors. This work deeply explains the fundamentals of SPR, different numerical methods used for designing the effective SPR chip along with applications of 2D materials for the same. We understand that there are numerous reports available in the literature comprising the same topic but such as a comprehensive review covering the all above-discussed topics is still missing. The target audience of this review article are the students/researchers working in the fields of SPR based sensor devices. [ABSTRACT FROM AUTHOR]

Liquid crystals have numerous applications in various fields ranging from drug delivery, gene therapy in biosciences to electronic display and sensors in the field of opt-electronics and material science. In recent years, the properties of liquid crystals have been tailored by truncating the terminal atom(s) or group of atoms and/or by doping different types of nanomaterials; such as nanodots, nanorods, nanotubes, nanoplatelets, etc. Controlled assembly of nanoparticles in liquid crystal media can provide an alternative method to tailor new and desired opto-electronic properties in uniquely arranged quantum dots. This self-assembly of nanoparticles produces new hybrid (composite) materials having large number of applications. Here, we review different applications of nanoparticles and liquid crystal systems and highlight different approaches for achieving the hierarchical arrangement of nanoparticles in liquid crystal media. Here, phenomena like quantum dot self-assembly, formation of hollow microstructures, memory effect, and formation of microcapsules, etc. in presence of liquid crystal media are revisited and discussed critically. Band-gap-tailoring has emerged as a major thrust area because of numerous applications in making opto-electronic devices. Band-gap of liquid crystals can be also be tailored either by doping (metal) atoms or by nucleating their nano-clusters after removing their terminal groups. This phenomenon creates a lot of attraction among scientists. Hierarchical arrangement of nano-dots in liquid crystal media has gained a lot of interest, as they can possess special functional properties; many of which are known whereas many others need to be discovered. Hierarchical arrangement of nano-clusters can be obtained either by doping atoms into liquid crystals followed by a nucleation process or by forming molecular architectures by weak coupling between quantum dots because of van der Waal forces. Functional properties such as magnetic, physiochemical, and opto-electronic properties of the hybrid systems are different from their constituent parts, and thus the hybrid systems can find a vital role in the field of nanoscience and nanotechnology. Because of the aforesaid reasons, it has gained much attention in the last few decades. [ABSTRACT FROM AUTHOR]

10.1149/2.0051704jes 14 Sultanova E.D., Nizameev I.R., Kholin K.V., Kadirov M.K., Ovsyannikov A., Burilov V.A., Ziganshina A.Y., Antipin I.S., Igor A.S. Photocatalytic properties of hybrid materials based on a multicharged polymer matrix with encored TiO2 and noble metal (Pt, Pd or Au) nanoparticles. Son et al. [[24]], fabricated a functional hybrid polyimide (PI) alignment layer that reduces the difference in refractive index and greatly increases the transmittance of the device by introducing inorganic titanium dioxide (TiO SB 2 sb ) nanoparticles (NP) to the organic PI. The TiO SB 2 sb nanoparticles of 15 and 300 nm in size were surface-treated with stearic acid, and the PI mixture with TiO SB 2 sb NPs was spin-coated on an ITO substrate and then imidized to form a hybrid alignment layer. A. B. Shcherbakov et al. [[18]] present a review summarizing the state of the art and perspectives for the use of cerium oxide nanoparticles in advanced polymer composites for biomedical applications. [Extracted from the article]

Bacterial infections are one of the most serious health problems all over the world, which cause need for the discovery of new drug. Since antibiotic resistance is a major threat to both humans and the environment, there is a need for studies on the antimicrobial properties of different forms of traditionally used plants. The seeds of Coriandrum sativum were used to isolate essential oil (EO) and to synthesize silver nanoparticles (C-AgNPs). The synthesized AgNPs were characterized by UV-Visible spectrophotometry, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), X-ray difraction (XRD) and Fourier Tranmission Infrared (FTIR). The major oil constituents were characterized by GC-MS as Linalool (79.12%), Camphor (6.16%), γ-Terpinene (2.82%) and α-Pinene (2.67%). The surface plasmon resonance (SPR) of C-AgNPs at 437 nm was recorded on the UV-Vis spectrometer. The spherical and homogenous of C-AgNPs was presented in SEM images. EDX showed elemental distribution and confirmed C-AgNPs. A characteristic intense peak was at 3.0 keV. The antibacterial activities of the essential oil and AgNPs form of Coriandrum sativum seed against Staphylococcus aureus ATCC 29213 and Escherichia coli ATCC 25922 bacteria were investigated by broth microdilution test. C-AgNPs and essential oil of coriander can be expected to provide future opportunities in nanomedicine and materials science. C-AgNPs can be displayed synergistic antimicrobial effect when used in combination with essential oil. [ABSTRACT FROM AUTHOR]

Plasmon‐molecule coupling has recently been attracted great research interest in material science and quantum optics with a multitude of potential applications. In this work, using the linear combination of atomic orbitals real‐time‐propagation rt‐time dependent density functional theory (TDDFT) technique (LCAO‐rt‐TDDFT) and transition contribution maps, we investigate the optical and plasmonic features of a hybrid nanosystem comprising an elliptical‐shaped metal nanoring (ENR) and a couple of benzene molecules (located in close proximity at both sides of the ENR short axis and/or long axis). We find that pristine ENR exhibits localized surface plasmon resonances (LSPRs) and plasmon‐molecule coupling in hybrid nanosystems is highly sensitive to the location of the molecules. More specifically, when benzene molecules are placed at both sides of the ENR short axis, the dominant peak in the photoabsorption spectrum sustains its LSPR features with a significant enhancement in intensity. On the other hand, in an alternative situation where benzene molecules are placed at both sides of the ENR long axis, the dominant peak in the photoabsorption spectrum splits into three with diminishing LSPR features. [ABSTRACT FROM AUTHOR]

The surface‐enhanced Raman scattering (SERS) effect was discovered by Richard Van Duyne et al. in 1977. He and coworkers also first utilized an innovative strategy that used SERS to record spectra on such SERS‐inactive substrate surfaces as n‐gallium arsenide (100) surfaces, which were modified by silver nano‐islands. This nanostructure‐enhanced Raman spectroscopy on flat surfaces (NERSoFS) enabled such SERS applications to be expanded to a variety of materials by virtue of SERS‐active nanostructures such as Au or Ag nanoparticles and shell‐isolated nanoparticles. However, most of such systems, although yielding Raman spectra, produce rather low enhancements, especially when used to record spectra on flat surfaces of SERS‐inactive materials. In this work, along with the direction of Van Duyne's borrowing‐SERS strategy and on the basis of the strategy of cascading optical coupling, we consider a theoretically designed optical configuration, based on an attenuated total reflection‐cascading nanostructure to produce enhanced Raman spectroscopy (ATRc‐NERS) on flat surfaces. This system can effectively harvest the incident light, thereby boosting the local optical field of the incident light and also moderately increasing the radiation field of the Raman‐scattered signals. In this way, one can gain 1–2 additional orders of magnitude in Raman enhancement over present NERSoFS systems both on metallic and nonmetallic flat surfaces, which are otherwise SERS‐inactive. This ATRc‐NERS strategy can potentially be used to develop ultrasensitive and versatile tools for surface science, material science, catalysis, electrochemistry, and micro‐electronics and micro‐LED industries. [ABSTRACT FROM AUTHOR]

With an increase in awareness about the need for green chemistry, there is a shift in focus towards identifying eco‐compatible technologies that can improve product yield and eliminate the use or generation of hazardous compounds. An immediate practical example of such an approach is the development of sustainable methods for alcohol oxidation as alternatives to the current processes that are energy intensive and rely on ecotoxic chemicals. In this regard, heterogeneous photocatalysis has been identified as a robust technique to catalyze reactions under benign conditions, which would otherwise require harsh synthesis routes. With the advent of materials sciences and nanotechnology, there has been a tremendous increase in the scope of applicability of photocatalysis in fine chemicals synthesis. Though an attractive choice, much of the fundamental information pertaining to catalyst activity, selectivity and reaction conditions for optimum conversion are still to be investigated for most of these systems. To this end, this review will encompass recent achievements in the selective photocatalytic oxidation of alcohols by harnessing solar radiation as a viable source of energy. The discussion will be arranged based on common types of photocatalysts reported in literature, namely metal oxides (eg, TiO2 and ZnO, Nb2O5), sulphides (eg, CdS, CuS, and Bi2S3), and carbonaceous photocatalysts (eg, g‐C3N4). Several such candidates for photocatalysts will be discussed critically with the aim of providing useful insight into developing selective photocatalysts that can oxidize alcohols via eco‐friendly pathways along with high yields. [ABSTRACT FROM AUTHOR]

The plasmonic properties of individual metallic nanostructures are of great importance for application in surface science, materials science, and nanophotonics. Herein, being facilitated with a home-made flow device and pulsed laser irradiation, we proposed a batch preparation protocol towards spherical Au nanoparticles (Au NPs) and cage shell entrapped spherical core nanoparticles (Au@cAu NPs) with highly uniform morphology and a tunable size distribution. The Fano resonance behavior exhibited by the effective interaction between spherical Au NPs and the silicon surface has great potential for the design of ultrasensitive optical sensing devices. In comparison with the spherical Au NP, the individual Au@cAu NP displayed not only a red-shifted and broadened localized surface plasmon resonance (LSPR) scattering peak, but also a higher electromagnetic field enhancement. Therefore, the Au@cAu NPs offer a better choice for plasmonic enhancement-based applications in the red and near-infrared region. In general, the current work provides a new and easy method for the large-scale preparation of gold-based uniform nanostructures, and offers an avenue to understand the interference of different plasmon modes in plasmonic systems, which has potential applications in surface science. [ABSTRACT FROM AUTHOR]

Fluorescent metallic nanoparticles with high quantum yield are highly desirable for optical imaging in the fields of biology and materials science. We investigate the photoluminescence (PL) properties of Ag nanoplates, particularly triangular ones, systematically at the single-particle level under different excitation conditions. We find that their emission is controlled by surface plasmon resonances (SPRs). Because of their high geometric symmetry, the shape and intensity of the PL spectrum from Ag triangular nanoplates are independent of the excitation polarization. Under excitation wavelengths of 473, 532 and 633 nm, the PL quantum yield (QY) of Ag triangular nanoplates is found to be twice that of Au nanorods at similar SPR wavelengths. It can be attributed to the stronger and broader SPR response, which can make the PL more intense not only in the spatial domain but also over a larger range in the frequency domain. Our investigations will extend the application of Ag nanoplates in imaging, labeling, and emitting, especially at the single-molecule level, due to their ultra-bright, stable, and polarization-independent PL. This method to enhance the PL signal, in both the spatial and frequency domains, can be easily expanded to other systems. [ABSTRACT FROM AUTHOR]

Here, different monoclonal antibodies (mAb1, mAb2 and mAb3) of Ebola virus were screened in a real-time and label-free manner using surface plasmon resonance (SPR) to select an appropriate antibody for biosensor applications against a biological warfare agent. For this purpose, a gold SPR chip was modified with 4-mercaptobenzoic acid (4-MBA), and modification was confirmed by FTIR-ATR and EIS. The 4-MBA-modified gold SPR chip was used for immobilization of the recombinant nucleoprotein of Ebola (EBOV-rNP), and the interactions of mAb1, mAb2 and mAb3 were then investigated to determine the best mAb based on the affinity constant (KD), expressed as equilibrium dissociation constant. KD values of 809 nM, 350 pM and 52 pM were found for the interaction of mAb1, mAb2 and mAb3 of Ebola with the immobilized EBOV-rNP, respectively, thus reflecting the high affinity of mAb3. This was confirmed by ELISA results. The thermodynamic parameters (ΔG, ΔH and ΔS) for the interaction between mAb3 and EBOV-rNP were also determined, which revealed that the interaction was spontaneous, endothermic and driven by entropy. The SPR limit of detection of EBOV-rNP with mAb3 was 0.5 pg ml−1, showing mAb3 to be the best high-affinity antibody in our study. This study has opened up new possibilities for SPR screening of different monoclonal antibodies of BWA through the convergence of materials science and optical techniques. [ABSTRACT FROM AUTHOR]

The article explores the detection of single nanoparticle activity dynamics inside a model pore catalyst material. It mentions the results of a study reveal a general framework for single particle catalysis in the gas phase and highlight the importance of single particle approaches for the understanding of complex catalyst materials.

Inspired by the rapid progress and existing limitations in surface plasmon resonance (SPR) biosensing technology, we have summarized the recent trends in the fields of both chip-SPR and fiber optic (FO)-SPR biosensors during the past five years, primarily regarding smart layers design, multiplexing, continuous monitoring and in vivo sensing. Versatile surface chemistries, biomaterials and nanomaterials have been utilized thus far to generate smart layers on SPR platforms and as such achieve oriented immobilization of bioreceptors, improved fouling resistance and sensitivity enhancement, collectively aiming to improve the biosensing performance. Furthermore, often driven by the desires for time- and cost-effective quantification of multiple targets in a single measurement, efforts have been made to implement multiplex bioassays on SPR platforms. While this aspect largely remains difficult to attain, numerous alternative strategies arose for obtaining parallel analysis of multiple analytes in one single device. Additionally, one of the upcoming challenges in this field will be to succeed in using SPR platforms for continuous measurements and in vivo sensing, and as such match up other biosensing platforms where these goals have been already conquered. Overall, this review will give insight into multiple possibilities that have become available over the years for boosting the performance of SPR biosensors. However, because combining them all into one optimal sensor is practically not feasible, the final application needs to be considered while designing an SPR biosensor, as this will determine the requirements of the bioassay and will thus help in selecting the essential elements from the recent progress made in SPR sensing. Image 1 • Continuous progress in material sciences promotes SPR biosensors development. • Smart layers improve receptor orientation, fouling resistance and sensitivity. • Challenging multiplexing is complemented by parallel analysis on SPR biosensors. • Continuous and in vivo sensing with SPR biosensors remains yet to be attained. [ABSTRACT FROM AUTHOR]

The research field of plasmonics is concerned with the interaction of light with free electrons in conducting media, thus, having a natural emphasis on metal nanostructures while now also being explored in several other novel material systems ranging from macromolecules and two-dimensional materials (such as graphene) to doped semiconductors. SPP9 opened with a plenary talk by Thomas W. Ebbesen on polaritons in material science, including perspectives on strong-coupling phenomena in plasmonics as a new state of matter. Kaltenecker et al. use scanning near-field microscopy to investigate interference patterns caused by surface plasmon polaritons on mono-crystalline gold platelets with ultra-smooth surfaces [[25]]. Exciton-plasmon polariton coupling and hot carrier generation in 2D SiB semiconductors: a first-principles study. [Extracted from the article]

The article presents the study of subnanometric metal clusters which exhibit anomalous catalytic activity, suggesting innovative applications as next-generation materials. Topics discussed include subnanosensitive vibrational technique established based on the surface-enhanced Raman spectroscopy; chemical and structural natures of subnanomaterials; and rational design of subnanomaterials on the atomic scale for practical applications.

Both increasing demand for ultrasensitive detection in the scientific community and significant new breakthroughs in materials science field have inspired and promoted the development of new-generation multifunctional plasmonic sensing platforms by adopting promising plasmonic nanomaterials. Recently, high-quality surface plasmon resonance (SPR) sensors, assisted by two dimensional (2D) nanomaterials including 2D van der Waals (vdWs) materials (such as graphene/graphene oxide, transition metal dichalcogenides (TMDs), phosphorene, antimonene, tellurene, MXenes, and metal oxides), 2D metal−organic frameworks (MOFs), 2D hyperbolic metamaterials (HMMs), and 2D optical metasurfaces, have emerged as a class of novel plasmonic sensing platforms that show unprecedented detection sensitivity and impressive performance. This review of recent progress in 2D nanomaterials-enhanced SPR platforms will highlight their compelling plasmonic enhancement features, working mechanisms, and design methodologies, as well as discuss illustrative practical applications. Hence, it is of great importance to describe the latest research progress in 2D nanomaterials-enhanced SPR sensing cases. In this review, we present some concepts of SPR enhanced by 2D nanomaterials, including the basic principles of SPR, signal modulation approaches, and working enhancement mechanisms for various 2D materials-enhanced SPR systems. In addition, we also demonstrate a detailed categorization of 2D nanomaterials-enhanced SPR sensing platforms and comment on their ability to realize ultrasensitive SPR detection. Finally, we conclude with future perspectives for exploring a new generation of 2D nanomaterials-based sensors. [ABSTRACT FROM AUTHOR]

Recently, the importance of nanomaterials in various fields such as materials science, chemistry, and biology enhanced rapidly. Selenium is an essential trace element having great significance and used in electronics, sensors, catalysis, optics, and medicines applications. Herein, we synthesized the selenium nanoparticles (SeNPs) via hydrothermal approach known for its environmental friendliness, simplicity, and inexpensiveness; by using sodium selenite as a precursor and L-ascorbic acid as reducing and stabilizing agent. Further, obtained SeNPs were characterized by different techniques such as UV-visible spectrophotometer, Fourier transforms infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and particle size distribution. The Uv-vis result confirmed the SeNPs formation with its surface Plasmon resonance peak. FTIR was tested to analyze the functional groups liable for the synthesis of SeNPs. XRD peaks also meet with the standard of SeNP's (JCPDS: 06-0362). SEM, TEM and histogram of particles size analysis of SeNPs showed the hexagonal structure with 169.11 nm mean size. The prepared SeNPs could be a promising candidate for a wide range of applications. [ABSTRACT FROM AUTHOR]

Studies on the properties of plasmonic materials and new chemical biological sensors are very important to our understanding of biological systems in single cells. Since the advent of nanofabrication techniques, plasmonic nanostructures have been widely used in various research fields including material science, biology, and medicine. The optical, electronic and catalytic properties of plasmonic nanostructures can be tuned very broadly by controlling their size, shape, and composition. Traditional optical biosensors based on the plasmonic properties of nanostructures have led to the development of high sensitivity, temporal-spatially resolved, and high-throughput plasmonic optical imaging techniques through assembly optimization of light sources, detectors, and other optical components. These techniques have been applied to single-cell research. Here, we briefly provide various applications of plasmonic nanostructures used for single-cell analysis and summarize the advanced detection and imaging techniques at the single-cell level. Plasmonic nanostructures and various plasmonic devices used for enhanced detecting and imaging in single cells. Image 1 • Application of plasmonic nanostructures to single-cell research in enhanced plasmonic biosensor development. • Bioimaging and detection techniques at the single-cell level based on the optical properties of plasmonic nanostructures. • Current achievements in fluorescence-free super-resolution imaging technology for single-cell analysis. [ABSTRACT FROM AUTHOR]

Grating-coupled surface plasmon field-enhanced fluorescence spectroscopy (GC-SPFS) with optical bound/free (B/F) separation technique was developed by employing a highly directional fluorescence with polarization of surface plasmon-coupled emission (SPCE) to realize highly sensitive immunoassay regardless of the ligand affinity. A highly sensitive immunoassay system with GC-SPFS was constructed using a plastic sensor chip reproducibly fabricated in-house by nanoimprinting and applied to the quantitative detection of an anti-lysozyme single-domain antibody (sdAb), to compare conventional washing B/F separation with optical B/F separation. Differences in the affinity of the anti-lysozyme sdAb, induced by artificial mutation of only one amino acid residue in the variable domain were attributed to higher sensitivity than that of the conventional Biacore surface plasmon resonance (SPR) system. The detection limit (LOD; means of six replicates of the zero standard plus three standard deviations) of the GC-SPFS immunoassay with optical B/F separation, was estimated to be 1.2 ng/ml with the low-affinity ligand (mutant sdAb Y52A: KD level was of the order of 10−7 ~ 10−6 M) and was clearly improved as compared to that (LOD: 9.4 ng/ml) obtained with the conventional washing B/F separation. These results indicate that GC-SPFS with the optical B/F separation technique offers opportunities to re-evaluate low-affinity biomaterials that are neither fully utilized nor widespread, and could facilitate the creation of novel and innovative methods in drug and diagnostic development. [ABSTRACT FROM AUTHOR]

Proteins from their native conformation convert into highly ordered fibrillar aggregation under particular conditions; that are described as amyloid fibrils. α-Synuclein (α-Syn) is a small natively unfolded protein that its fibrillation is the causative factor of Parkinson’s disease. One important approach in the development of therapeutic agents is the use of small molecules (such as flavonoids) that could specifically and efficiently inhibit the aggregation process. In this study the effect of few herbal extract (Berberis, Quercus robur, Zizyphus vulgaris, Salix aegyptica) containing flavonoids were investigated on fibril formation of α-syn by using conventional methods such as ThT fluorescence, circular dichroism (CD) spectroscopy and transmission electron microscopy (TEM). The interaction of extracts were also analysed by surface plasmon resonance (SPR). Among extracts, Salix aegyptica revealed the highest inhibitory effect on fibril formation. As expected, Salix aegyptica extract also exhibited the highest affinity toward α-syn. Cell viability using MTT assay revealed that fibrils alone were more toxic than those containing the extract. Overall, we demonstrated that the affinity of compounds used in this study corresponds to their ability to arrest fibrillation and reduce cellular toxicity of α-syn fibrils. [ABSTRACT FROM AUTHOR]

The surface plasmon resonance (SPR) technique is a powerful method to detect chemical molecules. Fluorescent spectroscopy is a subject of great interest in the field of material science and biology. Recently, some optical sensors, based on plasmonic properties of nanomaterial, were introduced to enhance the investigation of the interaction of molecular while detecting the low concentration of molecular. The surface plasmon-coupled emission (SPCE) technique is a merit and accurate method to evaluate the interaction of nanomaterials and molecular. SPCE is based on fluorescence properties of interest molecule, and the surface plasmon enhances the fluorescence signal. According to SPR theory, the condition of excitation of fluorophore could be used in obtaining the SPCE signal. SPCE can be used to detect toxic chemicals and investigate the human molecular. In this review, the theory, experimental setup, condition of SPCE, and role of metal nanoparticles in SPCE were reviewed. In the end, the application of SPCE was presented for detection and monitoring the chemical material, heavy metal, and biologic molecules. [ABSTRACT FROM AUTHOR]