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Immune checkpoint inhibitors (ICIs) emerged as promising immunotherapies for cancer treatment, harnessing the patient's immune system to fight and eliminate tumor cells. However, despite their potential and proven efficacies, checkpoint inhibitors still face important challenges such as the tumor heterogeneity and resistance mechanisms, and the complex in vitro testing, which limits their widespread applicability and implementation to treat cancer. To address these challenges, we propose a novel analytical technique utilizing biomimetic label-free nanoplasmonic biosensors for rapid and reliable screening and evaluation of checkpoint inhibitors. We have designed and fabricated a low-density nanostructured plasmonic sensor based on gold nanodisks that enables the direct formation of a functional supported lipid bilayer, which acts as an artificial cell membrane for tumor ligand immobilization. With this biomimetic scaffold, our biosensing approach provides real-time, highly sensitive analysis of immune checkpoint pathways and direct assessment of the blocking effects of monoclonal antibodies in less than 20 min/test. We demonstrate the accuracy of our biomimetic sensor for the study of the programmed cell death protein 1 (PD1) checkpoint pathway, achieving a limit of detection of 6.7 ng/mL for direct PD1/PD-L1 interaction monitoring. Besides, we have performed dose–response inhibition curves for an anti-PD1 monoclonal antibody, obtaining a half maximal inhibitory concentration (IC50) of 0.43 nM, within the same range than those obtained with conventional techniques. Our biomimetic sensor platform combines the potential of plasmonic technologies for rapid label-free analysis with the reliability of cell-based assay in terms of ligand mobility. The biosensor is integrated in a compact user-friendly device for the straightforward implementation in biomedical and pharmaceutical laboratories. [ABSTRACT FROM AUTHOR]

Localized surface plasmon resonance (LSPR) is an intriguing phenomenon that can break diffraction limitations and exhibit excellent light-confinement abilities, making it an attractive strategy for enhancing the light absorption capabilities of photodetectors. However, the complex mechanism behind this enhancement is still plaguing researchers, especially for hot-electron injection process, which inhibits further optimization and development. A clear guideline for basic physical model, enhancement mechanism, material selection and architectural design for LSPR photodetector are still required. This review firstly describes the mainstream understanding of fundamental physical modes of LSPR and related enhancement mechanism for LSPR photodetectors. Then, the universal strategies for tuning the LSPR frequency are introduced. Besides, the state-of-the-art progress in the development of LSPR photodetectors is briefly summarized. Finally, we highlight the remaining challenges and issues needed to be resolved in the future research. [ABSTRACT FROM AUTHOR]

Polarization photodetectors (PPDs) based on 2D materials hold great promise for ultracompact polarimeters due to their ability to directly detect polarization states. However, the existing PPDs based on 2D materials tend to focus on a single metric, making it challenging to obtain both a large polarization ratio (PR) and high responsivity (R). Here, black phosphorus (BP) PPDs are proposed under a nanowire configuration that enables large PR and high R simultaneously. Benefitting from the anisotropic coupling between the BP crystal and the nanowire geometry, specific light‐field distributions are formed under orthogonally polarized light incidences, through selectively exciting the localized surface plasmon and leaky‐mode resonances. A large carrier concentration gradient inherent to this structure is formed to induce a high response contrast and a large Dember current, enabling an ultrahigh PR ≈ 118.4, R ≈ 802.42 A W−1, and ultrashort response time ≈ 636 ps. Finally, a key‐free optical encryption communication system is constructed, demonstrating one of its promising applications. [ABSTRACT FROM AUTHOR]

ABSTRACT Integration of localized surface plasmon resonance (LSPR) metallic nanocrystals into photocatalysis is an intriguing approach for light‐driven organic transformations. However, uncertain direction of hot carriers is a grand challenge, which fails to take full advantage of the LSPR excitation. In this work, core–shell gold@ceria nanosphere–supported segregated palladium species (Au@CeO2–Pd) have developed to steer the light absorption capability and charge carrier migration. Under simulated solar light irradiation, the core–shell–satellite Au@CeO2–Pd exhibited efficient light harvesting and colossal activity in the Suzuki coupling reaction. The plasmon‐induced hot electrons overpassed the Schottky barrier at the Au@CeO2 interfaces and migrated from Au core to CeO2 shell accordingly. Subsequently, the photogenerated electrons and hot electrons migrated from Au@CeO2 core–shells to Pd, which acted as an electron acceptor. Detailed photocatalytic mechanism studies revealed that both photoexcited electrons and holes were the main active species involved in the photocatalytic Suzuki coupling reaction process. In particular, the diphenyl yield over Au@CeO2–Pd catalyst was ~1.7 times higher than that of core–shell–satellite Au@SiO2–Pd, where a 19‐nm‐thick SiO2 shell was introduced to prevent the migration of hot electrons. This distinctly certified that the hot electrons transfer in the core–shell–satellite Au@CeO2–Pd under illumination played an important role to drive Suzuki reaction. Overall, this design of core–shell–satellite Au@CeO2–Pd plasmonic photocatalyst has the potential in the field of photo‐driven organic transformations. [ABSTRACT FROM AUTHOR]

The conventional method for synthesizing gold nanobipyramids (AuNBPs) is well established. However, the cytotoxicity resulting from the conjugates between hexadecyltrimethylammonium bromide (CTAB) and gold limits their biomedical applications. This study introduces a dual surfactant approach with CTAB and sodium oleate (NaOL) in the seed‐mediated synthesis of the AuNBPs, which can significantly reduce the CTAB concentration to 10 mM. Additionally, optimal growth conditions are achieved by varying the volumes of seed solution, AgNO3, and HCl. Under low CTAB concentrations, AuNBPs with tunable sizes and localized surface plasmon resonances between 600 and 1200 nm are successfully synthesized, as characterized by UV–vis‐NIR spectroscopy, transmission electron microscopy (TEM), and finite‐difference time‐domain (FDTD) simulations. This work demonstrates a method for synthesizing AuNBPs at low CTAB concentrations using binary surfactants and provides a framework applicable to the synthesis of other metallic nanomaterials. [ABSTRACT FROM AUTHOR]

A multimode fiber-based sensor is proposed and demonstrated for the detection of lead traces in contaminated water. The sensing mechanism involves using a light sheet to excite a specific group of skew rays that optimizes light absorption. The sensing region features an inline microbubble structure that funnels the skew rays into a tight ring, thereby intensifying the evanescent field. The sensitivity is further refined by incorporating gold nanoparticles, which amplify the evanescent field strength through localized surface plasmon resonance. The gold nanoparticles are functionalized with oxalic acid to improve specificity for lead ion detection. Experiment results demonstrated the significantly enhanced absorption sensitivity of the proposed sensing method for large center offsets, achieving a detection limit of 0.1305 ng/mL (the World Health Organization safety limit is 10 ng/mL) for concentrations ranging from 0.1 to 10 ng/mL. [ABSTRACT FROM AUTHOR]

In order to enhance the responsivity, response speed and response spectral range of 2-D MoS2 photodetectors, high-quality multilayer MoS2 nanosheets were prepared by inserting tetrahexyl ammonium chloride (THA+) into bulks MoS2 through an electrochemical workstation and ultrasound-assisted exfoliation process. Thereafter, the MoS2 photodetectors were prepared by the spin-coating the prepared MoS2 nanosheets on the substate. Subsequently, the detector was modified by the Au nanorods (Au NRs) with double plasmon modes to further enhance the interaction between the photo sensing layer and the incident light. Experimental results show that the responsivity of the MoS2/Au NRs photodetector is improved from 2.4 x 10-3 A/W to 0.484 A/W, and the response time is boosted from 50 ms to 20 ms. In summary, this work not only provides a facile and effective method to expand the detectable spectral range of the photo detector, but also improve the performance of the photo detector. [ABSTRACT FROM AUTHOR]

Carbon nanotubes feature one‐dimensional nature of collective excitations, wherein strong confinement of surface plasmons severely hinders the liberation of hot electrons (HEs), posing grand challenges for their utilization in photochemistry. In this study, we prototypically achieved directed HEs flow and extraction in hybrid plasmonic CNN based on cup‐stacked carbon nanotubes (CSCNTs), taking advantage of their privileged edge‐plane sites. The localized pz electronic states and accessible intersubband plasmon excitations in the near‐infrared (NIR) regime stands in striking contrast to the conventional concentric carbon nanotubes, as evidenced by combined photo‐induced force microscopy (PiFM) and transient photocurrent response. The hybrid comprising intimately integrated CSCNTs‐C3N4 effectively sustains interfacial electronic states and underlies the energy extraction out of plasmonic components. The CNN demonstrates almost near‐unity NIR light‐driven CO2 reduction to CO with a rate of 1.35 μmol g−1 h−1. This work sheds light on the exploitation of metal‐free carbon‐based plasmonic nanostructures for photocatalytic applications. [ABSTRACT FROM AUTHOR]

The visualization of the spatial distributions of gases from various sources is essential to understanding the composition, localization, and behavior of these gases. In this study, an inkjet-printed localized surface plasmon resonance (LSPR) subpixel gas sensor array was developed to visualize the spatial distributions of gases and to differentiate between acetic acid, geraniol, pentadecane, and cis-jasmone. The sensor array, which integrates gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), and fluorescent pigments, was positioned 3 cm above the gas source. Hyperspectral imaging was used to capture the LSPR spectra across the sensor array, and these spectra were then used to construct gas information matrices. Principal component analysis (PCA) enabled effective classification of the gases and localization of their sources based on observed spectral differences. Heat maps that visualized the gas concentrations were generated using the mean squared error (MSE) between the sensor responses and reference spectra. The array identified and visualized the four gas sources successfully, thus demonstrating its potential for gas localization and detection applications. The study highlights a straightforward, cost-effective approach to gas sensing and visualization, and in future work, we intend to refine the sensor fabrication process and enhance the detection of complex gas mixtures. [ABSTRACT FROM AUTHOR]

Cu-based nanocrystals are desirable for high efficiency catalysis, although they are easily oxidized under ambient conditions. Alloying Au and Cu provides the strategy for Cu-contained nanocrystals toward both high stability and high catalytic activity. However, a synthetic method of homogeneous alloy nanocrystals with tunable composition in aqueous solutions is lacking. Specific composition for achieving both enhanced stability and high catalytic activity remains elusive. Herein, coreduction of Au3+ and Cu2+ was performed through controlling the kinetics of the coreduction to form AuCu alloyed shells on the Au nanorod (NR) cores and obtain Au@AuCu NRs under the protection of nitrogen. The Cu atomic fraction (atom %) of the shell was finely tuned from 0 to 100% by controlling the fraction of Cu2+ cations in the growth solution. For Au@Au0.85Cu0.15 NRs, epitaxial growth of AuCu alloy on the Au NR was evidenced with about 4.0% lattice mismatch due to Cu alloying in the Au lattice by high-resolution transmission electron microscopy. Au@AuCu NRs with different aspect ratios were also obtained for tuning longitudinal plasmonic resonance. Stability characterization indicates that the Au@AuCu NRs with Cu atom % in the shell lower than 15% are of enhanced stability, while an increase in Cu atom % in the shell from 0 to 15.3 and 100% leads to dramatic reduction of the activation energy, Ea, of p-nitroaniline from 111 to 45 and 33 kJ/mol, respectively. Therefore, Au@Au0.85Cu0.15 NRs are preferable for high catalytic activity and enhanced stability. [ABSTRACT FROM AUTHOR]

Shape control has been a major theme of nanocrystal research in terms of synthesis, property tailoring, and optimization of performance in a variety of applications. Among the possible shapes, bipyramids are unique owing to their symmetry, planar defects, and exposed facets. In this article, we focus on the colloidal synthesis of noble‐metal nanocrystals featuring a triangular bipyramidal shape, together with highlights of their properties and applications. We start with a brief discussion of the general classification and requirements for the nucleation and growth of bipyramidal nanocrystals, followed by specific aspects regarding the synthetic methods with a focus on the roles of reduction, etching, and capping, as well as controls of facet, size, aspect ratio, and corner truncation. In the end, we illustrate how these aspects affect the properties of bipyramidal nanocrystals for plasmonic and catalytic applications, together with future perspectives. [ABSTRACT FROM AUTHOR]

This study investigates the optical properties of diffraction gratings using localized surface plasmon resonance (LSPR) with metal nano-hemispheres. We fabricated metal nano-hemisphere gratings (MNHGS) with Ga, Ag, and Au and examined their wavelength-selective diffraction properties. Our findings show that these gratings exhibit peak diffraction efficiencies at 300 nm, 500 nm, and 570 nm, respectively, corresponding to the LSPR wavelengths of each metal. The MNHGs were created through thermal nanoimprint and metal deposition, followed by annealing. The experimental and simulation results confirmed that the MNHGs selectively diffract light at their resonance wavelengths. Applying these findings to third-order nonlinear laser spectroscopy (MPT-TG method) enhances measurement sensitivity by reducing background noise through the selective diffraction of pump light while transmitting probe light. This innovation promises a highly sensitive method for observing subtle optical phenomena, enhancing the capabilities of nonlinear laser spectroscopy. [ABSTRACT FROM AUTHOR]

Metal nanocages exhibit localized surface plasmon resonance that strongly absorbs and scatters light at specific wavelengths, making them potentially valuable for photothermal therapy and biological imaging applications. However, investigations on metal nanocages are still confined to high-cost and small-scale synthesis. The comprehensive analysis of optical properties and optimal size parameters of metal nanocages is rarely reported. This paper simulates the effects of materials (Ag, Au, and Cu), size parameters, refractive index of the surrounding medium, and orientation on the light absorption and scattering characteristics of the nanocages using the finite-element method and the size-dependent refractive-index model for metal nanoparticles. The results show that the Ag nanocages have excellent light absorption and scattering characteristics and respond significantly to the size parameters, while the refractive index and orientation of the surrounding medium have less effect on them. The Au nanocages also possess superior light absorption properties at specific incident wavelengths. This study also identified the optimized sizes of three metal nanocages at incident light wavelengths commonly used in biomedicine; it was also found that, under deep therapy conditions, Ag nanocages in particular exhibit the highest volume absorption and scattering coefficients of 0.708 nm−1 and 0.583 nm−1, respectively. These findings offer theoretical insights into preparing target nanocage particles for applications in photothermal therapy and biological imaging. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the surface plasmon characteristics of periodic silver nanodisk structures fabricated on a dielectric thin-film spacer layer on a Ag mirror substrate (NanoDisk on Mirror: NDoM) through finite difference time domain (FDTD) simulations and experiments involving actual sample fabrication. Through FDTD simulations, it was confirmed that the NDoM structure exhibits two sharp peaks in the visible range, and by adjusting the thickness of the spacer layer and the size of the nanodisk structure, sharp peaks can be obtained across the entire visible range. Additionally, we fabricated the NDoM structure using electron beam lithography (EBL) and experimentally confirmed that the obtained peaks matched the simulation results. Furthermore, we discovered that applying annealing at an appropriate temperature to the fabricated structure enables the adjustment of the resonance peak wavelength and enhances the scattering intensity by approximately five times. This enhancement is believed to result from changes in the shape and size of the nanodisk structure, as well as a reduction in grain boundaries in the metal crystal due to annealing. These results have the potential to contribute to technological advancements in various application fields, such as optical sensing and emission enhancement. [ABSTRACT FROM AUTHOR]

When illuminated by a resonant laser, noble metal nanoparticles immersed in liquids can efficiently produce a huge amount of heat and rapidly vaporize surrounding liquid, leading to the nucleation of plasmonic bubbles. Plasmonic bubbles are gaining increasing attention and emerged in numerous applications due to their unique properties and excellent controllability, such as microfabrication, micromanipulation, robot propulsion, molecule enrichment, and clinical therapies. In this review paper, the research progress of plasmonic bubbles in the past decade is summarized, including the plasmonic effect‐induced heat generation, experimental methods of plasmonic bubble observation, growth dynamics of plasmonic bubbles, approaches of optomechanical energy conversion via plasmonic bubbles, as well as their applications. This work provides a comprehensive understanding of the state of the art in the field and inspires researchers to explore more promising applications of plasmonic bubbles in different fields, like biology, microfluidics, and micromanufacturing. [ABSTRACT FROM AUTHOR]

Plasmonic materials have been extensively explored for surface-enhanced Raman scattering (SERS) due to their high tunability and excellent localized electric field enhancement. Most research for now has focused on noble metals, with limited investigation into corrosion-resistant materials for SERS effects. In this study, a photolithography process is firstly used to create a patterned dot array on a silicon substrate. Next, magnetron sputtering is employed to deposit molybdenum films, finally resulting in the molybdenum truncated cone array substrates for SERS applications. The fabricated truncated cone array experimentally facilitates the coupling of localized surface plasmon polaritons, consistent with simulation results obtained via the finite-difference time-domain method. The formation of hot spots between the cone unit cell arrays leads to the improved Raman signals and can act as traps for target molecules. This study demonstrates that molybdenum-based micro-nano structures can serve as reliable SERS substrates for sensitive molecular sensing applications in highly corrosive environments. [ABSTRACT FROM AUTHOR]

Driven by their exceptional optical characteristics, robust chemical stability, and facile bioconjugation, gold nanoparticles (AuNPs) have emerged as a preferred material for detection and biosensing applications in scientific research. This study involves the development of a simple, rapid, and cost-effective colorimetric immuno-sensing probe to detect aflatoxin B1 and zearalenone using AuNP antibody (AuNP-mAb) conjugates. Anti-toxin antibodies were attached to the AuNPs by using the physical adsorption method. The colorimetric immunosensor developed operates on the principle that the optical properties of the AuNP are very sensitive to aggregation, which can be induced by a critical high salt concentration. Although the presence of antibodies on the AuNP surface inhibits the aggregation, these antibodies bind to the toxin with higher affinity, which leads to exposure of the surface of AuNPs and aggregation in a salt environment. The aggregation triggers a noticeable but variable alteration in color from red to purple and blueish gray, as a result of a red shift in the surface plasmon resonance band of the AuNPs. The extent of the shift is dependent on the toxin exposure dose and can be quantified using a calibration curve through UV–Visible–NIR spectroscopy. The limit of detection using this assay was determined to be as low as 0.15 ng/mL for both zearalenone and aflatoxin B1. The specificity of the prepared immunoprobe was analyzed for a particular mycotoxin in the presence of other mycotoxins. The developed immunoprobe was evaluated for real-world applicability using artificially spiked samples. This colorimetric immunoprobe based on localized surface plasmon resonance (LSPR) has a reduced detection limit compared to other immunoassays, a rapid readout, low cost, and facile fabrication. [ABSTRACT FROM AUTHOR]

Abstract Herein, we investigated the distinctive scattering properties exhibited by single gold nanorods coated with palladium (AuNRs@Pd), with variations in the Pd shell thicknesses and morphologies. AuNRs@Pd were synthesized through bottom-up epitaxial Pd growth using two different concentrations of Pd precursor. These single AuNRs@Pd displayed the characteristic of subradiant and superradiant localized surface plasmon resonance peaks, characterized by a noticeable gap marked by a Fano dip. We revealed the effect of local refractive index (RI) on the subradiant and superradiant peak energies, as well as the Fano dip in the scattering spectra of AuNRs@Pd with different Pd shell thicknesses. We demonstrated the applicability of the inflection points (IFs) method on detecting peaks and dip changes across different RIs. Thin AuNRs@Pd1mM displayed more pronounced sensitivity to peak shifts in response to variations in local RIs compared to thick AuNRs@Pd2mM. In contrast, thick AuNRs@Pd2mM exhibited greater sensitivity to changes in curvature near the subradiant and superradiant peak energies rather than peak shift sensitivity across different local RIs. Moreover, the Fano dip shift was more noticeable in thick AuNRs@Pd2mM compared to thin AuNRs@Pd1mM across different local RIs. Therefore, we provided new insight into the RI sensitivity on subradiant, superradiant, and Fano resonance modes in single AuNRs@Pd.

The universal strategies for the anisotropic synthesis of Ag2Se nanomaterials (NMs) have been rarely investigated, despite their unique thermoelectric and luminescent properties. Here, we present the metal-to-semiconductor (M–SC) transformation of anisotropic Ag NMs with sphere, plate, cube, rod, and wire structures to synthesize anisotropic Ag2Se NMs. We demonstrate that the controlled formation of Se0(aq) and its redox reaction with Ag0 on the surface of the Ag2Se NMs are the keys to preserving the initial shapes. The reaction mechanism involving the gradual migration of Se from the surface to the core of the Ag NMs was simulated and supported by density functional theory. The structure-dependent catalytic properties of the Ag2Se NMs were extensively investigated, and the cubic Ag2Se NMs exhibited the highest specific catalytic activities. The M–SC transformation-based synthesis of anisotropic Ag2Se NMs would be highly valuable for expanding the structural diversity of semiconductor NMs and their structure-dependent applications. [ABSTRACT FROM AUTHOR]

Dynamic manipulation of an object's infrared radiation characteristics is a burgeoning technology with significant implications for energy and information fields. However, exploring efficient stimulus–spectral response mechanism and realizing simple device structures remains a formidable challenge. Here, a novel dynamic infrared emissivity regulation mechanism is proposed by controlling the localized surface plasmon resonance absorption of aluminum‐doped zinc oxide (AZO) nanocrystals through ultraviolet photocharging/oxidative discharging. A straightforward device architecture that integrates an AZO nanocrystal film with an infrared reflective layer and a substrate, functioning as a photo‐induced dynamic infrared emissivity modulator, which can be triggered by weak ultraviolet light in sunlight, is engineered. The modulator exhibits emissivity regulation amount of 0.72 and 0.61 in the 3–5 and 8–13 µm ranges, respectively. Furthermore, the modulator demonstrates efficient light triggering characteristic, broad spectral range, angular‐independent emissivity, and long cyclic lifespan. The modulator allows for self‐adaptive daytime radiative cooling and nighttime heating depending on the ultraviolet light in sunlight and O2 in air, thereby achieving smart thermal management for buildings with zero‐energy expenditure. Moreover, the potential applications of this modulator can extend to rewritable infrared displays and deceptive infrared camouflage. [ABSTRACT FROM AUTHOR]

Abiotic stress tends to induce oxidative damage to enzymes and organelles that in turns hampers the phosphorylation process and decreases the adenosine triphosphate (ATP) productivity. Artificial assemblies can alleviate abiotic stress and simultaneously provide nutrients to diminish the oxidative damage. Here, we have integrated natural acid phosphatase (ACP) and ATP synthase with plasmonic Au clusters in a biomimetic microreactor. ACP immobilized on the Au clusters is harnessed to generate proton influx to drive ATP synthase and concurrently supply phosphate to improve phosphorus availability to combat phosphorus‐deficiency stress. In tandem with the reactive oxygen species (ROS) scavenging and the photothermal functionality of Au clusters, such an assembled microreactor exhibits an improved abiotic stress tolerance and achieves plasmon‐accelerated ATP synthesis. This innovative approach offers an effective route to enhance the stress resistance of ATP synthase‐based energy‐generating systems, opening an exciting potential of these systems for biomimicking applications. [ABSTRACT FROM AUTHOR]

Hyperbolic metamaterials (HMMs) are known for their robust light–matter interaction and ability to generate volume plasmon polaritons (VPPs). Au nanoparticles (Au NPs) enable to enhance this interaction through localized surface plasmon resonance (LSPR), creating intense local electric fields. However, combining LSPR and VPPs in one device remains unexplored. This study proposes and demonstrates Au NP‐coupled‐HMMs (NPCHMMs), integrating Au NPs with HMMs to enhance random laser action and lower the lasing threshold. NPCHMMs boost emission intensity by ≈6 times compared to pure HMMs, with a ≈47% reduction in lasing threshold. Based on Fermi's golden rule, the calculated transition rate in NPCHMMs surpasses the algebraic sum of the individual transition rates derived from HMMs and Au NPs. It reveals the effect of the coherent coupling between the transition matrix elements of VPP and LSPR. This research indicates that NPCHMMs are a promising platform to create high‐performance optical and optoelectronic devices, such as lasers and phototransistors, for a wide range of application in many fields. [ABSTRACT FROM AUTHOR]

The standard laboratory methods used to detect Salmonella are time-consuming, leading to unavoidable delays, which can be costly (e.g., food checks at customs) or even dangerous when quick alarms are needed (e.g., for potential outbreaks). To address this problem, we propose a rapid two-step colorimetric immunoassay. In the first step, gold nanoparticles interact with the sample, while in the second step, an optimized amount of saline solution is added to induce cluster formation among the unbound nanoparticles, providing a color change that inversely correlates with the bacteria concentration. The nanoparticles were functionalized using a technique based on UV activation of the antibodies, resulting in oriented antibodies with antigen-binding regions in the proximity of the surface. While a color change can be observed with the naked eye at relatively higher bacterial concentrations, a more quantitative approach based on UV–visible spectrum measurements allowed us to achieve a limit of detection of 1 cfu/mL in chicken samples. The test can be completed in 15 min and performed on-site, paving the way for widespread applications of our biosensor in the field of food safety. [ABSTRACT FROM AUTHOR]

The extensive use of pesticides and fertilizers in agriculture has led to significant environmental pollution, particularly in aqueous systems. This review provides an inclusive overview of the advancements in the application of gold nanoparticles (GNPs), specifically for the sensing of pesticides and fertilizers on surface water. The novelty of this work lies in its focused analysis of the unique localized surface plasmon resonance properties of GNPs that enable highly sensitive and selective detection of contaminants on surface water. Various synthesis methods and detection mechanisms are discussed, emphasizing the integration of GNP‐based sensors with modern analytical techniques to enhance detection limits and response time. The review also highlights the significance of monitoring agricultural chemicals in water systems from an environmental perspective. In addition, this review also reveals the potential of GNPs contribution toward sustainable agricultural practices by providing reliable, rapid, and cost‐effective sensing solutions. Future perspectives on the development of GNP‐based sensors, including the fundamental challenges in designing GNP sensors, such as incorporation with other materials, miniaturized and portable sensing devices, and field‐testing validation are also presented. [ABSTRACT FROM AUTHOR]

Despite extensive research on utilizing plasmonic hot carriers to advance photovoltaics and photocatalysts, achieving high hot‐carrier flux remains challenging due to their rapid relaxation. Recent studies have shown that combining plasmonic metals with perovskites improves hot‐electron flow, due to the slow hot‐electron relaxation in perovskites. Additionally, perovskites offer the advantage of facile bandgap tuning through composition changes. Herein, the influence of tuning the perovskite bandgap on the lifetime and flow of hot electrons in a perovskite/plasmonic Au/TiO2 nanodiode is explored. The findings reveal that perovskites with wider bandgaps exhibit improved hot‐electron lifetime and flow, attributed to the modified hot‐electron energy favoring a slower energy loss rate, as verified by ultrafast transient absorption spectroscopic analysis. It is believed that the results successfully demonstrate the integration of engineered hot‐carrier physics into device functions, providing valuable guidance for the design of optimized hot‐carrier‐based devices in the future. [ABSTRACT FROM AUTHOR]

Aqueous synthesis of covellite CuS nanoparticles holds significant importance in the field of nanomaterials and environmental sustainability. Using water as a solvent and reactant in the synthesis process aligns with green chemistry principles. It enhances nanoparticle production's scalability and safety. CuS nanoparticles have gained attention for their diverse applications in catalysis, energy storage, and environmental remediation. Aqueous synthesis reduces the environmental footprint associated with hazardous organic solvents, making it an eco‐friendly approach. We report on synthesis routes toward covellite CuS nanocrystals (NCs), emphasizing easy and fast synthesis techniques. Additionally, we develop a flow synthesis of small near infrared active CuS NCs in a custom‐made flow reactor. Combining the advantages of aqueous synthesis and flow chemistry yields a robust and sustainable method for producing covellite CuS NCs readily dispersible in water medium, paving the way for their widespread application in diverse fields. [ABSTRACT FROM AUTHOR]

Plasmonic intragap nanostructures (PINs) have garnered intensive attention in Raman-related analysis due to their exceptional ability to enhance light–matter interactions. Although diverse synthetic strategies have been employed to create these nanostructures, the emphasis has largely been on PINs with simple configurations, which often fall short in achieving effective near-field focusing. Three-dimensional (3D) complex PINs, distinguished by their intricate networks of internal gaps and voids, are emerging as superior structures for effective light trapping. These structures facilitate the generation of hot spots and hot zones that are essential for enhanced near-field focusing. Nevertheless, the synthesis techniques for these complex structures and their specific impacts on near-field focusing are not well-documented. This review discusses the recent advancements in the synthesis of 3D complex PINs and their applications in surface-enhanced Raman scattering (SERS). We begin by describing the foundational methods for fabricating simple PINs, followed by a discussion on the rational design strategies aimed at developing 3D complex PINs with superior near-field focusing capabilities. We also evaluate the SERS performance of various 3D complex PINs, emphasizing their advanced sensing capabilities. Lastly, we explore the future perspective of 3D complex PINs in SERS applications. [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]

Herein, a localized surface plasmon resonance‐based sensor for volatile organic compounds (VOCs) detection is developed. The sensors are fabricated as a hybrid nanostructure of gold nanoparticles coated with a tantalum oxide (TaO) thin film on a glass slide substrate through magnetron sputtering and thermal solid‐state dewetting techniques. The thickness of the TaO film varies between 10 and 70 nm. The optical properties of samples are characterized by UV‐Vis‐NIR spectrophotometry, while their morphologies are confirmed via transmission electron microscopy. The results show the shift of the minimum optical transmittance related to the TaO thickness. Electrical field simulations are performed to predict the sensitivity of the prepared samples for VOCs detection. In addition, the sensors are tested with different VOCs, including formaldehyde, isopropanol, acetone, and methanol, which show good potential for practical applications. [ABSTRACT FROM AUTHOR]

Plasmonic rulers (PRs) linking nanoscale distance dependence spectral shifts are important for studying cellular microenvironments and biomarker detection. The traditional PR design employs tethering metal nanoparticle pairs using synthetic and biopolymers that severely suffer from reproducibility issues, as well as lack reversibility. Here, the fabrication of novel PRs is reported through the formation of self‐assembled monolayers (SAMs) of photoswitchable molecular machines chemically tethered onto sharp‐tip gold nanostructures (Au NSs). This unique and highly sensitive PR utilizes localized surface plasmon resonance (LSPR) properties of Au NSs to spectroscopically evaluate dipole–dipole coupling between NSs and photoisomerizable spiropyran (SP)‐merocyanine (MC) conjugates in the solid‐state. It is observed that the SAM‐modified NSs are extremely sensitive to the photoisomerization of SP‐to‐MC, resulting in LSPR shifts as large as 5.6 nm for every 1.0 Å change in distance. The highly dipolar MC changes the NS‐SAM interfacial polarizability and alters the dipole–dipole coupling leading to the ultrasensitive PR is hypothesized. The hypothesis is supported theoretically by calculating dipole polarizability of an inorganic‐organic heterodimer model and experimentally by determining work function and interfacial dipole values. Taken together, this work represents the fabrication of next‐generation PRs, which hold great promise for advanced, plasmonic‐based sensors and optoelectronic device fabrication. [ABSTRACT FROM AUTHOR]

Signal transducers are crucial in bioassay platforms for converting target detection into recordable signals. Commonly used color development for immunoassays involves enzymes and colorimetric substrates. However, due to cost and environmental issues, practical point‐of‐care testing requires alternative signal transducers. Growth‐induced extinction (absorption and scattering) of gold nanoclusters (AuNCs) is proposed as a novel approach for quantitative immunoassays. AuNCs devoid of localized surface plasmon resonance (LSPR) are used as seeds for growth reactions. Through reactions with a growth solution comprised of gold precursor and mild reductant, AuNCs of varying concentrations underwent controlled growth, resulting in nanoparticles of different sizes exhibiting distinct LSPR‐mediated extinction bands. Notably, the seed concentration exhibited a robust correlation with the resulting extinction of the grown particles on a small scale of 110 µL for a 96‐well microplate platform. To demonstrate this signal transduction mechanism, immunosorbent assays are performed using the conjugates of AuNC and detection antibody. The sandwich‐type assay successfully quantified a model antigen, human immunoglobulin G (hIgG), by monitoring LSPR wavelength and absorbance. This assay demonstrated a working range of 0.001–1 µg mL−1 and limit of detection of 1.19 ng mL−1. Signal transducers using the growth of AuNCs offer new alternative candidates for immunoassay platforms. [ABSTRACT FROM AUTHOR]

Developing novel catalysts with high activity and high stability for the methanol oxidation reaction (MOR) is of great importance for the ever-broader applications of methanol fuel cells. Herein, we present a facile technique for synthesizing Au10Pt1@MnO2 catalysts using a wet chemical method and investigate their catalytic performance for the MOR. Notably, the Au10Pt1@MnO2-M composite demonstrated a significantly high peak mass activity of 15.52 A mg(Pt)−1, which is 35.3, 57.5, and 21.9 times greater than those of the Pt/C (0.44 A mg(Pt)−1), Pd/C (0.27 A mg(Pt)−1), and Au10Pt1 (0.71 A mg(Pt)−1) catalysts, respectively. Comparative analysis with commercial Pt/C and Pd/C catalysts, as well as Au10Pt1 HSNRs, revealed that the Au10Pt1@MnO2-M composite exhibited the lowest initial potential, the highest peak current density, and superior CO anti-poisoning capability. The results demonstrate that the introduction of MnO2 nanosheets, with excellent oxidation capability, not only significantly increases the reactive sites, but also promotes the reaction kinetics of the catalyst. Furthermore, the high surface area of the MnO2 nanosheets facilitates charge transfer and induces modifications in the electronic structure of the composite. This research provides a straightforward and effective strategy for the design of efficient electrocatalytic nanostructures for MOR applications. [ABSTRACT FROM AUTHOR]

Ordered metal nanoparticle arrays have attracted considerable attention as promising substrates for surface-enhanced Raman spectroscopy owing to their dense and homogeneous distribution of "hot spots". However, achieving uniformity and stability in these structures remains challenging. In this study, we fabricated an Ag nanoparticle array (NPA)/monolayer MoS2 hybrid using an anodized aluminum template and a wet transfer method. The Ag NPA/MoS2 hybrid, after annealing at 290 °C, displayed exceptional sensitivity in detecting rhodamine 6G at concentrations as low as 10–12 M. This enhancement can be attributed to the enhanced coupling effect between the Ag nanoparticle arrays and MoS2, alongside the optimization of the Ag nanoparticle morphology. Moreover, the hybrid substrate annealed at 290 °C demonstrated outstanding reproducibility in both point-to-point and substrate-to-substrate measurements, with relative standard deviations of 5.39 and 7.24%, respectively. These findings highlight the potential of the Ag NPA/MoS2 hybrid for trace detection applications in food and environmental safety. [ABSTRACT FROM AUTHOR]

Oxidative dehydrogenation of propane (ODHP) is a reaction with significant practical significance. As for the industrial application of ODHP, it is challenging to achieve high activity and high propylene selectivity simultaneously. In this study, to overcome this obstacle, we designed a series of Cu/BN catalysts with unique morphologies for establishing a photothermal ODHP system with high efficiency and selectivity. Characterization and evaluation results revealed that Cu/BN-NS and Cu/BN-NF with enlarged specific surface areas exhibited higher catalytic activities. The localized surface plasmon resonance (LSPR) effect of Cu nanoparticles further enhanced the photothermal catalytic performances of Cu/BN catalysts under visible light irradiation. To the best of our knowledge, it is the first time to establish a BNbased photothermal ODHP catalytic system. This study is expected to pave pathways to realize high activity and propylene selectivity for the practical application of ODHP. [ABSTRACT FROM AUTHOR]

This work reveals the rules of using figures of merit on selecting efficient plasmonic nanoheaters. Here, a size dependence of plasmonic nanoparticle optical heating was disclosed. The continuous laser heating of gold nanospheres is evaluated exploring a theoretical approach and thermal lens spectroscopy, which allowed identifying micro-degree temperature changes of laser heated colloidal gold nanospheres of varying sizes. Our findings indicate that the temperature of photoheating colloidal particles rises according to the Joule number values. The optimal gold nanospheres diameter for efficient colloidal laser heating was identified to be 50 nm. Moreover, we demonstrated that long-time domain measurements of colloidal sample enable the identification of single-particle intermediate steady-state temperature. Considering a single particle, nanospheres with diameter larger than 80 nm exhibit superior heating performance than smaller particles, revealing that the optimal particle size for single-particle optical heating applications is different from the optimal particle size for collective heating of nanoparticles. Our results pave the way for the rational use of plasmonic nanoheaters in photothermal applications. [ABSTRACT FROM AUTHOR]

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

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid plaques in the brain. The toxicity of amyloid to neuronal cell surfaces arises from interactions between small intermediate aggregates, namely amyloid oligomers, and the cell membrane. The nature of these interactions changes with age and disease progression. In our previous work, we demonstrated that both membrane composition and nanoscale structure play crucial roles in amyloid toxicity, and that membrane models mimicking healthy neuron were less affected by amyloid than model membranes mimicking AD neuronal membranes. This understanding introduces the possibility of modifying membrane properties with membrane-active molecules, such as melatonin, to protect them from amyloid-induced damage. In this study, we employed atomic force microscopy and localized surface plasmon resonance to investigate the protective effects of melatonin. We utilized synthetic lipid membranes that mimic the neuronal cellular membrane at various stages of AD and explored their interactions with amyloid- β (1–42) in the presence of melatonin. Our findings reveal that the early diseased membrane model is particularly vulnerable to amyloid binding and subsequent damage. However, melatonin exerts its most potent protective effect on this early-stage membrane. These results suggest that melatonin could act at the membrane level to alleviate amyloid toxicity, offering the most protection during the initial stages of AD. [ABSTRACT FROM AUTHOR]

The double S-scheme electron transfer pathway of the Cu 2−x Se/T-Cd 0.5 Zn 0.5 S system leverages the synergistic effect of interface and bulk phase S-scheme homo-heterojunctions, along with the utilization of "hot electrons" generated by the LSPR effect, to facilitate efficient charge separation and transfer, thereby achieving enhanced performance in H 2 evolution. [Display omitted] • The twinned-Cd 0.5 Zn 0.5 S, composed of zinc blende and wurtzite Cd 0.5 Zn 0.5 S have excellent H 2 evolution activity. • Cu 2−x Se can further promote charge separation and enhance the H 2 evolution kinetics. • The Cu 2−x Se/T-Cd 0.5 Zn 0.5 S homo-heterojunctions with interface and bulk synergistic double S-scheme. • The injection of "hot electrons" generated by the LSPR effect of Cu 2−x Se into the T-Cd 0.5 Zn 0.5 S. The enhancement of charge separation and utilization efficiency in both the bulk phase and interface of semiconductor photocatalysts, as well as the expansion of light absorption range, are crucial research topics in the field of photocatalysis. To address this issue, twinned Cd 0.5 Zn 0. 5S (T -CZS) homojunctions consisting of wurtzite Cd 0.5 Zn 0.5 S (WZ-CZS) and zinc blende Cd 0.5 Zn 0.5 S (ZB-CZS) were synthesized via a hydrothermal method to facilitate the bulk-phase charge separation. Meanwhile, Cu 2−x Se with localized surface plasmon resonance effect (LSPR) generated by Cu vacancies was also obtained through a hydrothermal process. Due to their opposite electronegativity, a solvent evaporation strategy was employed to combine Cu 2−x Se and T -CZS by intermolecular electrostatic. After optimization, the photocatalytic hydrogen (H 2) evolution rate of 5 wt% Cu 2−x Se/ T -CZS reached an impressive value of 60 mmol∙h−1∙g−1, which was 4.6 and 66.6 times higher than that of pure Cu 2−x Se and T -CZS, respectively. Furthermore, this composites demonstrated a remarkable rate of 0.46 mmol∙h−1∙g−1 under near-infrared (NIR) wavelength (>800 nm). The enhanced performance observed in Cu 2−x Se/ T -CZS can be attributed to its unique and efficient double S-scheme charge transfer mechanism which effectively suppresses rapid recombination of electron-hole pairs both within the bulk phase and at the surface interfaces; this conclusion is supported by Density Functional Theory (DFT) calculations as well as electron paramagnetic resonance spectroscopy analysis. Moreover, incorporation of Cu 2−x Se enables effective utilization ultraviolet visible-near infrared (UV–Vis-NIR) light by the composites while facilitating injection "hot electrons" into T -CZS for promoting photocatalytic reactions. This study provides a potential strategy for achieving efficient solar energy conversion through synergistic integration of non-stoichiometric plasmonic materials with photocatalysts with twinned-twinned structures. [ABSTRACT FROM AUTHOR]

Objective: The concentration of the placental circulating factor in early pregnancy is often extremely low, and the traditional prediction method cannot meet the clinical demand for early detection preeclampsia in high-risk gravida. It is of prime importance to seek an ultra-sensitive early prediction method. Methods: In this study, finite-different time-domain (FDTD) and Discrete Dipole Approximation (DDA) simulation, and electron beam lithography (EBL) methods were used to develop a bowtie nanoantenna (BNA) with the best field enhancement and maximum coupling efficiency. Bio-modification of the placental circulating factor (sFlt-1, PLGF) to the noble nanoparticles based on the amino coupling method were explored. A BNA LSPR biosensor which can specifically identify the placental circulating factor in preeclampsia was constructed. Results: The BNA LSPR biosensor can detect serum placental circulating factors without toxic labeling. Serum sFlt-1 extinction signal (Δλmax) in the preeclampsia group was higher than that in the normal pregnancy group (14.37 ± 2.56 nm vs. 4.21 ± 1.36 nm), p = 0.008, while the serum PLGF extinction signal in the preeclampsia group was lower than that in the normal pregnancy group (5.36 ± 3.15 nm vs. 11.47 ± 4.92 nm), p = 0.013. The LSPR biosensor detection results were linearly consistent with the ELISA kit. Conclusions: LSPR biosensor based on BNA can identify the serum placental circulating factor of preeclampsia with high sensitivity, without toxic labeling and with simple operation, and it is expected to be an early detection method for preeclampsia. [ABSTRACT FROM AUTHOR]

The dual photothermal effects resulting from the non-radiative photon conversion of the D-A structure and the Au NPs LSPR effect, along with the enhanced charge carrier dynamics, catalyzed the efficient photoreduction of CO 2. [Display omitted] Conversion of CO 2 into high value-added fuels through the photothermal effect is an effective approach for utilizing solar energy. In this study, we prepared the CN-based photocatalyst Py-CTN-Au with both donor-acceptor (D-A) system and dual photothermal effects using a simple two-step method involving calcination and photo-deposition. Real-time monitoring with a thermal imaging camera revealed that Py-CTN-Au0.5 achieved a maximum stable temperature of 180 °C, which was approximately 1.2 times higher than that of Py-CTN (155 °C) and 1.9 times higher than that of g-CN (95 °C) under the same reaction conditions. Under the optimized reaction conditions, Py-CTN-Au0.5 exhibited a CO release rate of 30.59 umol g−1 after 4 h of reaction, which was 7.3 times higher than that of pure g-CN (4.18 umol g−1). The D-A system not only facilitated the separation and transformation of charge carriers but also induced a photothermal effect to accelerate the photoreduction of CO 2. Additionally, the cocatalyst Au nanoparticles (Au NPs) further enhanced the charge carrier dynamics and photothermal effect by increasing the built-in electric field intensity and localized surface plasmon resonance (LSPR) effect, respectively. The dual photothermal effects resulting from the non-radiative photon conversion of the D-A structure and the Au NPs LSPR effect, along with the enhanced charge carrier dynamics, catalyzed the efficient photoreduction of CO 2. DFT simulations were used to confirm the effect of D-A system and Au NPs. In-situ FTIR results demonstrated that the synergistic photothermal effect promoted the formation of the key intermediate species COOH*, which is beneficial for the photocatalytic reduction of CO 2. This study provides valuable insights into the multiple photothermal synergistic effects in photocatalytic reactions. [ABSTRACT FROM AUTHOR]

Introduction: Organic interfaces have recently emerged as a breakthrough trend in biomedical applications, demonstrating exceptional performance in stimulating retinal neuronal cells owing to their high flexibility and compatibility with tissues. However, the primary challenge associated with organic photovoltaics is their low efficiency compared to that of their inorganic counterparts. Among different approaches, embedding plasmonic metal nanoparticles (NPs) in active or buffer layers can efficiently improve photovoltaic cell performance. Methods: A cathode decorated with silver nanoparticles is introduced to increase the absorption Phenomenon and improve the interface performance as a computational study. In addition to embedding spherical silver nanoparticles in the active layer (A-AgNPs), a monolayer array of spherical AgNPs in the cathode electrode (K-AgNPs) is incorporated. In this configuration, the large K-AgNPs play dual roles: acting as cathode electrode and serving as plasmonic centers to increase light trapping and absorption. The bulk heterojunction PCPDTBT:PCBM is chosen as the active layer due to its favorable electronic properties. Results: Our computational analysis demonstrates a notable 10% enhancement in the photovoltaic cell current density for the developed structure with K-AgNPs in contrast to without them. Additionally, the simulation results reveal that the modeled device achieves a two-fold efficiency of the bare photovoltaic cell (without A-AgNPs and K-AgNPs), which is particularly evident at a low intensity of 0.26 mW/mm2. Discussion: This study aims to propose an efficient epiretinal prosthesis structure using a different strategy for plasmonic effects rather than conventional methods, such as incorporating NPs into the active or buffer layer. This structure can prevent the harmful side effects of using large metal NPs (r > 10 nm) in the active layer during exciton quenching, charge trapping, and recombination, which deteriorate the power conversion efficiency (PCE). [ABSTRACT FROM AUTHOR]

Modern integrated circuits have active components on the order of nanometers. However, optical devices are often limited by diffraction effects with dimensions measured in wavelengths. Nanoscale photodetectors capable of converting light into electrical signals are necessary for the miniaturization of optoelectronic applications. Strong coupling of light and free electrons in plasmonic nanostructures overcomes these limitations by confining light into sub-wavelength volumes with intense local electric fields. Localized electric fields are intensified at nanorod ends and in nanogap regions between nanostructures. Hot carriers generated within these high-field regions from nonradiative decay of surface plasmons can be injected into the conduction band of adjacent semiconductors, enabling sub-bandgap photodetection. The optical properties of these plasmonic photodetectors can be tuned by modifying antenna materials and geometric parameters like size, thickness, and shape. Electrical interconnects provide connectivity to convert light into electrical signals. In this work, interconnected nanogap antennas fabricated with 35 nm gaps are encapsulated with ALD-deposited TiO 2 , enabling photodetection via Schottky barrier junctions. Photodetectors with high responsivity (12 μ A/mW) are presented for wavelengths below the bandgap of TiO 2 (3.2 eV). These plasmonic nanogap antennas are sub-wavelength, tunable photodetectors with sub-bandgap responsivity for a broad spectral range. [ABSTRACT FROM AUTHOR]

Plasmonic metal nanostructures can simultaneously scatter and absorb light, with resonance wavelength and strength depending on their morphology and composition. This work demonstrates that unique dichroic effects and high‐contrast colour‐switching can be achieved by leveraging the resonant scattering and absorption of light by plasmonic nanostructures and the specular reflection of the resulting transmitted light. Using core/shell nanostructures comprising a metal core and a dielectric shell, we show that their spray coating on reflective substrates produces dichroic films that can display colour switching at different viewing angles. The high‐contrast colour switching, high flexibility in designing multicolour patterns, and convenience for large‐scale production promise their wide range of applications, including anticounterfeiting, mechanochromic sensing, colour display, and printing. [ABSTRACT FROM AUTHOR]

The influence of the geometrical parameters of truncated gold nanocones on the sensitivity of plasmon resonance systems based on them has been studied. The dependence of the bulk refractive index sensitivity on the height, side face inclination angle, and base diameter of the nanocone was studied by the finite-difference time domain method. The parameters corresponding to the highest sensitivity of biosensors based on these particles were identified, and ways to increase it were proposed. [ABSTRACT FROM AUTHOR]

Localized surface plasmon resonance (LSPR) biosensors, which enable nanoscale confinement and manipulation of light, offer the enhanced sensitivity and electromagnetic energy localization. The integration of LSPR with the fiber-optic technology has led to the development of compact and versatile sensors for miniaturization and remote sensing. This comprehensive review explores various sensor configurations, fiber types, and geometric shapes, highlighting their benefits in terms of sensitivity, integration, and performance improvement. Fabrication techniques such as focused non-chemical bonding strategies and self-assembly of nanoparticles are discussed, providing control over nanostructure morphology and enhancing sensor performance. Bio-applications of fiber-optic LSPR (FOLSPR) sensors are detailed, specifically in biomolecular interactions and analysis of proteins, pathogens and cells, nucleic acids (DNA and RNA), and other small molecules (organic compounds and heavy metal ions). Surface modification and detection schemes are emphasized for their potential for label-free and real-time biosensing. The challenges and prospects of FOLSPR sensors are addressed, including the developments in sensitivity, fabrication techniques, and measurement reliability. Integration with emerging technologies such as nanomaterials is highlighted as a promising direction for future research. Overall, this review provides insights into the advancements and potential applications of FOLSPR sensors, paving the way for sensitive and versatile optical biosensing platforms in various fields. [ABSTRACT FROM AUTHOR]

The sensitivity and optical properties of silver nanoprisms (triangular plates with round‐truncated corners) are investigated in this paper. Results of boundary element method simulations are compared with experimental results and literature data. Based on electron microscopy images of the synthesized nanoprisms, a single‐particle model is set up for simulations with three running parameters: edge length, thickness, and roundness (defined as the radius of the circumscribed circle divided by the edge length). These geometric parameters can be optimized during chemical synthesis to create sensors with improved sensitivity. The effect of biomolecular layers is also investigated. As a novel approach to improve the agreement between the simulated and experimentally measured extinction spectra, the single‐particle model is extended to consider the variation of the prisms' parameters in the form of distributions. The resulting extinction cross‐section spectra correspond well with the experimental data. The calculated bulk refractive index sensitivity is 670 nm/RIU (RIU stands for refractive index unit) for the single particle model (length = 150 nm, thickness = 10 nm, and roundness = 0.1), while (690 ± 5) nm/RIU for the extended model. The presented model and obtained relations between sensitivity and geometry can be effectively used to design and optimize the fabrication technologies for silver nanoprism‐based sensing applications. [ABSTRACT FROM AUTHOR]

Considering that more than 10 million people develop tuberculosis disease (TB) each year and that nearly 3 million of them are never diagnosed, label-free screening methods constitute one of the top public health priorities worldwide. Herein we report the fabrication of a plasmonic system for the detection of TB-associated antibodies. Gold nanoparticles (AuNPs) were synthesized at controlled sizes and modified to display antigen lipid glycans from mycobacteria, the group of organisms comprising the TB causal agent. Facile self-assembly procedures were employed to form mycobacterial phosphatidylinositol mannoside (PIM)-containing unilamellar liposomes (mycosomes) and to attach them onto gold surfaces using thiol chemistry. Using enzyme-linked immunoassays with rabbit hyperimmune sera, the constructs were found to specifically capture antilipid antibodies, presenting a dose-dependent response. Also, the functional hybrid nanoparticles showed localized surface plasmon resonance (LSPR) shifts of up to 2 nm upon their interaction with specific antibodies, indicating their suitability for the optical transduction of antigen–antibody reactions. Finally, the applicability of the system for real-world detection of TB-associated antibodies was demonstrated through analysis of 12 samples of human individuals, including 7 cases with pulmonary TB. To the best of our knowledge, this is the first biomimetic nanogold–lipid system for the implementation of lipids as immunosensing reagents for the plasmonic detection and diagnosis of TB. [ABSTRACT FROM AUTHOR]