A comparison increasing the photodegradation power of a Ag/g-C3N4 /CoNi-LDH nanocomposite: Photocatalytic activity toward water treatment.

For environmental applications, it is crucial to rationally design and synthesize photocatalysts with positive exciton splitting and interfacial charge transfer. Here, a novel Ag-bridged dual Z-scheme Ag/g-C3N4/CoNi-LDH plasmonic heterojunction was successfully synthesized using a simple method, with the goal of overcoming the common drawbacks of traditional photocatalysts such as weak photoresponsivity, rapid combination of photo-generated carriers, and unstable structure. These materials were characterized by XRD, FT-IR, SEM, TEM UV-Vis/DRS, and XPS to verify the structure and stability of the heterostructure. The pristine LDH, g-C3N4, and Ag/g-C3N4/CoNi-LDH composite were investigated as photocatalysts for water remediation, an environmentally motivated process. Specifically, the photocatalytic degradation of tetracycline was studied as a model reaction. The performance of the supports and composite catalyst were determined by evaluating both the degradation and adsorption phenomenon. The influence of several experimental parameters such as catalyst loading, pH, and tetracycline concentration were evaluated. The current study provides important data for water treatment and similar environmental protection applications.

Single-particle rotational sensing for analyzing the neutralization activity of antiviral antibodies.

Due to the pathogen-specific targeting, neutralization capabilities, and enduring efficacy, neutralizing antibodies (NAs) have received widespread attentions as a critical immunotherapeutic strategy against infectious viruses. However, because of the high variability and complexity of pathogens, rapid determination of neutralization activity of antiviral antibodies remains a challenge. Here, we report a new method, named as out-of-plane polarization imaging based single-particle rotational sensing, for rapid analysis of neutralization activity of antiviral antibody against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Using the spike protein functionalized gold nanorods (AuNRs) and angiotensin-converting enzyme 2 (ACE2) coated gold nanoparticles (AuNPs) as the rotational sensors and chaperone probes, we demonstrated the single-particle rotational sensing strategy for the measurement of rotational diffusion coefficient of the chaperone-bound rotational sensors caused by the specific spike protein-ACE2 interactions. This enables us to measure the neutralizing activity of neutralizing antibody from the analysis of dose-dependent changes in rotational diffusion coefficient (Dr) of the rotational sensors upon the treatment of SARS-CoV-2 antibody. With this technique, we achieved the quantitative determination of neutralization activity of a commercially available SARS-CoV-2 antibody (IC50, 294.1 ng/mL) with satisfying accuracy and anti-interference ability. This simple and robust method holds the potential for rapid and accurate evaluation of neutralization activity against different pathogenic viruses.

Photothermal induction of pyroptosis in malignant glioma spheroids using (16-mercaptohexadecyl)trimethylammonium bromide-modified cationic gold nanorods.

Plasmonic photothermal therapy (PPTT) employing plasmonic gold nanorods (GNRs) presents a potent strategy for eradication of tumors including aggressive brain gliomas. Despite its promise, there is a pressing need for a more comprehensive evaluation of PPTT using sophisticated in vitro models that closely resemble tumor tissues, thereby facilitating the elucidation of therapeutic mechanisms. In this study, we exposed 3D glioma spheroids (tumoroids) to (16-mercaptohexadecyl)trimethylammonium bromide-functionalized gold nanorods (MTAB-GNRs) and a near-infrared (NIR) laser. We demonstrate that the photothermal effect can be fine-tuned by adjusting the nanoparticle concentration and laser power. Depending on the selected parameters, the laser can trigger either regulated or non-regulated cell death (necrosis) in both mouse GL261 and human U-87 MG glioma cell lines, accompanied by translocation of phosphatidylserine in the membrane. Our investigation into the mechanism of regulated cell death induced by PPTT revealed an absence of markers associated with classical apoptosis pathways, such as cleaved caspase 3. Instead, we observed the presence of cleaved caspase 1, gasdermin D, and elevated levels of NLRP3 in NIR-irradiated tumoroids, indicating the activation of pyroptosis. This finding correlates with previous observations of lysosomal accumulation of MTAB-GNRs and the known lysosomal pathway of pyroptosis activation. We further confirmed the absence of toxic breakdown products of GNRs using electron microscopy, which showed no melting or fragmentation of gold nanoparticles under the conditions causing regulated cell death. In conclusion, PPTT using coated gold nanorods offers significant potential for glioma cell elimination occurring through the activation of pyroptosis rather than classical apoptosis pathways.

Designer Metasurfaces via Nanocube Assembly at the Air-Water Interface.

The advent of metasurfaces has revolutionized the design of optical instruments, and recent advancements in fabrication techniques are further accelerating their practical applications. However, conventional top-down fabrication of intricate nanostructures proves to be expensive and time-consuming, posing challenges for large-scale production. Here, we propose a cost-effective bottom-up approach to create nanostructure arrays with arbitrarily complex meta-atoms displaying single nanoparticle lateral resolution over submillimeter areas, minimizing the need for advanced and high-cost nanofabrication equipment. By utilizing air/water interface assembly, we transfer nanoparticles onto templated polydimethylsiloxane (PDMS) irrespective of nanopattern density, shape, or size. We demonstrate the robust assembly of nanocubes into meta-atoms with diverse configurations generally unachievable by conventional methods, including U, L, cross, S, T, gammadion, split-ring resonators, and Pancharatnam-Berry metasurfaces with designer optical functionalities. We also show nanocube epitaxy at near ambient temperature to transform the meta-atoms into complex continuous nanostructures that can be swiftly transferred from PDMS to various substrates via contact printing. Our approach potentially offers a large-scale manufacturing alternative to top-down fabrication for metal nanostructuring, unlocking possibilities in the realm of nanophotonics.

A structural peculiarity of Antarctic fish IgM drives the generation of an engineered mAb by CRISPR/Cas9.

IgM is the major circulating Ig isotype in teleost fish, showing in Antarctic fish unique features such as an extraordinary long hinge region, which plays a crucial role in antibody structure and function. In this work, we describe the replacement of the hinge region of a murine monoclonal antibody (mAb) with the peculiar hinge from Antarctic fish IgM. We use the CRISPR/Cas9 system as a powerful tool for generating the engineered mAb. Then, we assessed its functionality by using an innovative plasmonic substrate based on bimetallic nanoislands (AgAuNIs). The affinity constant of the modified mAb was 2.5-fold higher than that obtained from wild-type mAb against the specific antigen. Here, we show the suitability of the CRISPR/Cas9 method for modifying a precise region in immunoglobulin gene loci. The overall results could open a frontier in further structural modifications of mAbs for biomedical and diagnostic purposes.

Novel Ag@NH2-UiO-66(Zr) photocatalyst with controllable charge transfer pathways for efficient Cr(VI) remediation.

Rational fabrication of core-shell photocatalysts to hamper the charge recombination is extraordinarily essential to enhance photocatalytic activity. In this work, core-shell Ag@NH2-UiO-66 (Ag@NU) Schottky heterojunctions with low Ag content (1 wt%) were constructed by a two-step solvothermal method and adopted for Cr(VI) reduction under LED light. Typically, the one with the Ag: NH2-UiO-66 mass ratio (1 : 100) led to 100% Cr(VI) removal within 1 h, superior to bare NH2-UiO-66 and Ag/NH2-UiO-66 (Ag was directly decorated on NH2-UiO-66 surface). The enhanced photocatalytic activity was related to the migration of the electrons on the CB of NH2-UiO-66 to Ag NPs through a Schottky barrier, and thus the undesired charge carriers recombination was avoided. This result was also evidenced by Density functional theory (DFT) calculations. The computational simulations indicate that the introduction of Ag effectively narrowed the band gap of NH2-UiO-66, facilitating the transfer of photo-generated electrons, expanding the light absorption area, and significantly enhancing photocatalytic efficiency. Most importantly, such a core-shell structure can inhibit the formation of •O2-, letting the direct Cr(VI) reduction by photo-excited e-. In addition, this structure can also protect Ag from being oxidized by O2. Ten cyclic tests evidenced the Ag@NU had excellent chemical and structural stability. This research offers a novel strategy for regulating the Cr(VI) reduction by establishing core-shell photocatalytic materials.

Au@AuPd Core-Alloyed Shell Nanoparticles for Enhanced Electrocatalytic Activity and Selectivity under Visible Light Excitation.

Plasmonic catalysis has been employed to enhance molecular transformations under visible light excitation, leveraging the localized surface plasmon resonance (LSPR) in plasmonic nanoparticles. While plasmonic catalysis has been employed for accelerating reaction rates, achieving control over the reaction selectivity has remained a challenge. In addition, the incorporation of catalytic components into traditional plasmonic-catalytic antenna-reactor nanoparticles often leads to a decrease in optical absorption. To address these issues, this study focuses on the synthesis of bimetallic core@shell Au@AuPd nanoparticles (NPs) with ultralow loadings of palladium (Pd) into gold (Au) NPs. The goal is to achieve NPs with an Au core and a dilute alloyed shell containing both Au and Pd, with a low Pd content of around 10 atom %. By employing the (photo)electrocatalytic nitrite reduction reaction (NO2RR) as a model transformation, experimental and theoretical analyses show that this design enables enhanced catalytic activity and selectivity under visible light illumination. We found that the optimized Pd distribution in the alloyed shell allowed for stronger interaction with key adsorbed species, leading to improved catalytic activity and selectivity, both under no illumination and under visible light excitation conditions. The findings provide valuable insights for the rational design of antenna-reactor plasmonic-catalytic NPs with controlled activities and selectivity under visible light irradiation, addressing critical challenges to enable sustainable molecular transformations.

Novel biomimetic hybrid plasmonic nanocavity-based ECL strategy for the detection of extracellular vesicles.

Tumor-derived extracellular vesicles detection has emerged as an important clinical liquid biopsy approach for cancer diagnosis. In this work, we developed a novel hybrid plasmonic nanocavity consisting of hexagonal Au nanoplates nanoarray, SnS2/Au nanosheet layer and biomimetic lipid bilayer. Firstly, the hybrid plasmonic nanocavity combined the optical confinement for the ECL regulation and the biological recognition for the detection of extracellular vesicles. Secondly, MXene-derived Ti2N QDs have been prepared as ECL nanoprobe to label extracellular vesicles. Moreover, biomimetic lipid bilayer with specific aptamer was used to identify extracellular vesicles and integrate Ti2N QDs into the nanocavity with membrane fusion strategy. Due to the significant electromagnetic field enhancement at the cavity region, the hybrid plasmonic nanocavity provided strong field confinement to concentrate and redistribute the ECL emission of QDs with a 9.3-fold enhancement. The hybrid plasmonic nanocavity-based ECL sensing system improved the spatial controllability of EVs analysis and the accurate resolution of specific protein. It achieved the sensitive detection of extracellular vesicles in ascites and successfully distinguished the peritoneal metastasis of gastric cancer.

Machine learning-assisted label-free colorectal cancer diagnosis using plasmonic needle-endoscopy system.

Early and accurate detection of colorectal cancer (CRC) is critical for improving patient outcomes. Existing diagnostic techniques are often invasive and carry risks of complications. Herein, we introduce a plasmonic gold nanopolyhedron (AuNH)-coated needle-based surface-enhanced Raman scattering (SERS) sensor, integrated with endoscopy, for direct mucus sampling and label-free detection of CRC. The thin and flexible stainless-steel needle is coated with polymerized dopamine, which serves as an adhesive layer and simultaneously initiates the nucleation of gold nanoparticle (AuNP) seeds on the needle surface. The AuNP seeds are further grown through a surface-directed reduction using Au ions-hydroxylamine hydrochloride solution, resulting in the formation of dense AuNHs. The formation mechanism of AuNHs and the layered structure of the plasmonic needle-based SERS (PNS) sensor are thoroughly analyzed. Furthermore, a strong field enhancement of the PNS sensor is observed, amplified around the edges of the polyhedral shapes and at nanogap sites between AuNHs. The feasibility of the PNS sensor combined with endoscopy system is further investigated using mouse models for direct colonic mucus sampling and verifying noninvasive label-free classification of CRC from normal controls. A logistic regression-based machine learning method is employed and successfully differentiates CRC and normal mice, achieving 100% sensitivity, 93.33% specificity, and 96.67% accuracy. Moreover, Raman profiling of metabolites and their correlations with Raman signals of mucus samples are analyzed using the Pearson correlation coefficient, offering insights for identifying potential cancer biomarkers. The developed PNS-assisted endoscopy technology is expected to advance the early screening and diagnosis approach of CRC in the future.

Self-Assembled TiN-Metal Nanocomposites Integrated on Flexible Mica Substrates towards Flexible Devices.

The integration of nanocomposite thin films with combined multifunctionalities on flexible substrates is desired for flexible device design and applications. For example, combined plasmonic and magnetic properties could lead to unique optical switchable magnetic devices and sensors. In this work, a multiphase TiN-Au-Ni nanocomposite system with core-shell-like Au-Ni nanopillars embedded in a TiN matrix has been demonstrated on flexible mica substrates. The three-phase nanocomposite film has been compared with its single metal nanocomposite counterparts, i.e., TiN-Au and TiN-Ni. Magnetic measurement results suggest that both TiN-Au-Ni/mica and TiN-Ni/mica present room-temperature ferromagnetic property. Tunable plasmonic property has been achieved by varying the metallic component of the nanocomposite films. The cyclic bending test was performed to verify the property reliability of the flexible nanocomposite thin films upon bending. This work opens a new path for integrating complex nitride-based nanocomposite designs on mica towards multifunctional flexible nanodevice applications.

Dealing with plasmonic crystal biosensors: Sensitivity assessment of nanodisks/nanoholes arrayed plasmonic system for label-free DNA detection.

Label-free optical deoxyribonucleic acid (DNA) sensing with arrayed plasmonic nanostructures (plasmonic crystals) is a promising technology for biomedical diagnosis and bioanalytical science. Plasmonic biosensors can detect target biomolecules by utilizing the shift in plasmonic resonance caused by changes in the surrounding refractive index (RI) attributed to the capture of target biomolecules using a recognizer. Conventional explanations for the sensitivity of plasmonic crystals are based on bulk (BRIS) and surface RI sensitivities (SRIS) for basic plasmonic nanoparticles despite their unique properties such as surface lattice resonances (SLRs), wherein localized surface plasmons (LSPs) cooperatively oscillate with their pitch. Therefore, investigating the sensitivity of SLRs is imperative for improving sensing performance. In this study, the sensitivity of adenomatous polyposis coli (APC) gene-related DNA hybridization detection of complementary plasmonic crystals composed of nanodisks (PNDs) on or under plasmonic nanoholes (PNHs) was investigated considering the SLR properties. The BRIS was measured using the conventional definition of the peak wavelength shift per unit RI increment (nm/RIU) followed by the SRIS measurement using the layer-by-layer method. The BRIS and SRIS measurements reflect the practical sensitivity for DNA detection. PNHs had higher sensitivity than PNDs, with a limit of detection of 0.30 nM. Further, only the SLR-based mode responded to localized RI changes because of DNA hybridization, whereas both the LSPs- and SLR-based modes responded to uniform RI changes caused by layer-by-layer coating. Our investigation will open up possibilities and opportunities for plasmonic crystal biosensors.

Symmetry-Guided Engineering of Polarization by 2D Moiré Metasurfaces.

Cylindrical vector (CV) beams exhibit spatially varying polarization important in optical communication, super-resolution microscopy, and high-throughput information processing. Compared to radially or azimuthally polarized CV beams that are cylindrically symmetric, hybrid-electric (HE) beams offer increased optical tunability because of their polygonally symmetric polarizations. However, efforts to generate and isolate HE beams have relied on bulky optical assemblies or devices with complex and stringent fabrication requirements. Here, we report a moiré-based metasurface approach to engineer HE polarization states with high degrees of rotational symmetry. Importantly, polarization symmetries can be tailored based only on the reciprocal lattice of the metasurface and not the real-space patterns. Our modular method outlines important design principles for shaping light at the nanoscale.

Integration of Plasmonic Ag(I) Clusters and Fe(II) Porphyrinates into Metal-Organic Frameworks for Efficient Photocatalytic CO2 Reduction Coupling with Photosynthesis of Pure H2O2.

Efficient photocatalytic CO2 reduction coupled with the photosynthesis of pure H2O2 is a challenging and significant task. Herein, using classical CO2 photoreduction site iron porphyrinate as the linker, Ag(I) clusters were spatially separated and evenly distributed within a new metal-organic framework (MOF), namely Ag27TPyP-Fe. With water as electron donors, Ag27TPyP-Fe exhibited remarkable performances in artificial photosynthetic overall reaction with CO yield of 36.5 µmol g-1 h-1 and ca. 100% selectivity, as well as H2O2 evolution rate of 35.9 µmol g-1 h-1. Since H2O2 in the liquid phase can be more readily separated from the gaseous products of CO2 photoreduction, high-purity H2O2 with a concentration up to 0.1 mM was obtained. Confirmed by theoretical calculations and the established energy level diagram, the reductive iron(II) porphyrinates and oxidative Ag(I) clusters within an integrated framework functioned synergistically to achieve artificial photosynthesis. Furthermore, photoluminescence spectroscopy and photoelectrochemical measurements revealed that the robust connection of Ag(I) clusters and iron porphyrinate ligands facilitated efficient charge separation and rapid electron transfer, thereby enhancing the photocatalytic activity.

Novel approach for green synthesis of stable gold nanoparticles with dried turmeric root extract: investigations on sensor and catalytic applications.

In this study, we present the synthesis of gold nanoparticles (AuNPs) using a completely green synthesis method without the use of any additional functionalizing agent, except dried turmeric root extract. The significant synthesis parameters were optimized, and the applicability of AuNPs was investigated in areas such as plasmonic and fluorescent sensing of aluminum (Al3⁺) and chromium (Cr3⁺) ions, reduction of 4-nitrophenol (4-NP), and degradation of methylene blue (MB) and methyl orange (MO) dyes. Characterization studies were performed using UV-Vis spectroscopy, TEM, FTIR, and XRD, revealing that the AuNPs predominantly had a spherical morphology and a very small particle size of 8.5 nm, with stability maintained up to 120 days. The developed AuNP-based plasmonic sensors relied on aggregation-induced decreases in absorption, along with a red shift in the spectra. Fluorescence sensing demonstrated a linear increase in intensity with increasing concentrations of Al3⁺ and Cr3⁺, with detection limits of 0.83 and 1.19 nM, respectively. The catalytic activities of AuNPs were tested in reducing 4-NP and degradations of MB and MO dyes (binary system) in tap water and wastewater, with the reactions following pseudo-first-order kinetics. This study highlights the potential of AuNPs synthesized from turmeric roots for various environmental and sensing applications.

Selective oxidation of glycerol mediated by surface plasmon of gold nanoparticles deposited on titanium dioxide nanowires.

This paper describes an alternative method for the in situ synthesis of gold nanoparticles (AuNPs) with a particle size of less than 3 nm, using nanoreactors formed by reverse micelles of 1,4-bis-(2-ethylhexyl) sulfosuccinate sodium (AOT) and nanoparticle stabilization with l-cysteine, which favor the preparation of nanoparticles with size and shape control, which are homogeneously dispersed (1% by weight) on the support of titanium dioxide nanowires (TNWs). To study the activity and selectivity of the prepared catalyst (AuNPs@TNWs), an aqueous solution of 40 mM glycerol was irradiated with a green laser (λ = 530 nm, power = 100 mW) in the presence of the catalyst and O2 as an oxidant at 22 °C for 6 h, obtaining a glycerol conversion of 86% with a selectivity towards hydroxypyruvic acid (HA) of more than 90%. From the control and reactions, we concluded that the Ti-OH groups promote the glycerol adsorption on the nanowires surface and the surface plasmon of the gold nanoparticles favors the selectivity of the reaction towards the hydroxypyruvic acid.

DNA Origami-Engineered Plasmonic Nanoprobes for Targeted Cancer Imaging.

Plasmonic nanomaterials bearing targeting ligands are of great interest for surface-enhanced Raman scattering (SERS)-based bioimaging applications. However, the practical utility of SERS-based imaging strategies has been hindered by the lack of a straightforward method to synthesize highly sensitive SERS-active nanostructures with high yield and efficiency. In this work, leveraging DNA origami principles, we report the first-in-class design of a SERS-based plasmonically coupled nanoprobe for targeted cancer imaging (SPECTRA). The nanoprobe harnesses a cancer cell targeting DNA aptamer sequence and vibrational tag with stretching frequency in the cell-silent Raman window. Through the integration of aptamer sequence specific for DU145 cells, we show the unique capabilities of SPECTRA for targeted imaging of DU145 cells. Our results demonstrate that the scalability, cost-effectiveness, and reproducibility of this method of fabrication of SERS nanoprobes can serve as a versatile platform for creating nanoprobes with broad applications in the fields of cancer biology and biomedical imaging.

Plasmonic Hydrogel Actuators for Octopus-Inspired Photo/Thermoresponsive Smart Adhesive Patch.

Octopuses are notable creatures that can dynamically adhere to a variety of substrates owing to the efficient pressure control within their suction cups. An octopus' suckers are sealed at the rim and function by reducing the pressure inside the cavity, thereby creating a pressure difference between the ambient environment and the inner cavity. Inspired by this mechanism, we developed a plasmonic smart adhesive patch (Plasmonic AdPatch) with switchable adhesion in response to both temperature changes and near-infrared (NIR) light. The AdPatch incorporates an elastic, nanohole-patterned elastomer that mimics the structure of octopus suckers. Additionally, a monolayer of gold nanostars (GNSs) is coated on the patch, facilitating a NIR light-responsive photothermal effect. A musclelike, thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel functions as a volumetric actuator to regulate cavity pressure. When exposed to heat or light, the PNIPAM hydrogel shrinks, enabling the AdPatch to achieve strong suction adhesion (134 kPa at 45 °C, 71 kPa at 85 mW cm-2). Owing to its capability to achieve light-triggered remote adhesion without the need for external pressure, the Plasmonic AdPatch can be employed to transfer ultrathin films and biosensors to fragile organs without causing damage.

Label-free and liquid state SERS detection of multi-scaled bioanalytes via light-induced pinpoint colloidal assembly.

Surface-enhanced Raman scattering (SERS) has been extensively applied to detect complex analytes due to its ability to enhance the fingerprint signals of molecules around nanostructured metallic surfaces. Thus, it is essential to design SERS-active nanostructures with abundant electromagnetic hotspots in a probed volume according to the dimensions of the analytes, as the analytes must be located in their hotspots for maximum signal enhancement. Herein, we demonstrate a simple method for detecting robust SERS signals from multi-scaled bioanalytes, regardless of their dimensions in the liquid state, through a photothermally driven co-assembly with colloidal plasmonic nanoparticles as signal enhancers. Under resonant light illumination, plasmonic nanoparticles and analytes in the solution quickly assemble at the focused surface area by convective movements induced by the photothermal heating of the plasmonic nanoparticles without any surface modification. Such collective assemblies of plasmonic nanoparticles and analytes were optimized by varying the optical density and surface charge of the nanoparticles, the viscosity of the solvent, and the light illumination time to maximize the SERS signals. Using these light-induced co-assemblies, the intrinsic SERS signals of small biomolecules can be detected down to nanomolar concentrations based on their fingerprint spectra. Furthermore, large-sized biomarkers, such as viruses and exosomes, were successfully detected without labels, and the complexity of the collected spectra was statistically analyzed using t-distributed stochastic neighbor embedding combined with support vector machine (t-SNE + SVM). The proposed method is expected to provide a robust and convenient method to sensitively detect biologically and environmentally relevant analytes at multiple scales in liquid samples.

Proximal High-Index Metamaterials based on a Superlattice of Gold Nanohexagons Targeting the Near-Infrared Band.

Plasmonic nanoparticles can be assembled into a superlattice, to form optical metamaterials, particularly targeting precise control of optical properties such as refractive index (RI). The superlattices exhibit enhanced near-field, given the sufficiently narrow gap between nanoparticles supporting multiple plasmonic resonance modes only realized in proximal environments. Herein, the planar superlattice of plasmonic Au nanohexagons (AuNHs) with precisely controlled geometries such as size, shape, and edge-gaps is reported. The proximal AuNHs superlattice realized over a large area with selective edge-to-edge assembly exhibited the highest-ever-recorded RI values in the near-infrared (NIR) band, surpassing the upper limit of the RI of the natural intrinsic materials (up to 10.04 at λ = 1.5 µm). The exceptionally enhanced RI is derived from intensified in-plane surface plasmon coupling across the superlattices. Precise control of the edge-gap of neighboring AuNHs systematically tuned the RI as confirmed by numerical analysis based on the plasmonic percolation model. Furthermore, a 1D photonic crystal, composed of alternating layers of AuNHs superlattices and low-index polymers, is constructed to enhance the selectivity of the reflectivity operating in the NIR band. It is expected that the proximal AuNHs superlattices can be used as new optical metamaterials that can be extended to the NIR range.

Intrinsic Superchirality in Planar Plasmonic Metasurfaces.

Plasmonic metasurfaces with spatial symmetry breaking are crucial materials with significant applications in fields such as polarization-controlled photonic devices and nanophotonic platforms for chiral sensing. In this paper, we introduce planar plasmonic metasurfaces, less than one-tenth of a wavelength thick, featuring nanocavities formed by three equilateral triangles. This configuration creates uniform, thin metasurfaces. Through a combination of experimental measurements and numerical modeling, we demonstrate the inherent superchirality of these plasmonic metasurfaces. We address the challenge of achieving a strong enhancement of optical chirality in the visible spectrum, reaching levels comparable to those of 3D chiral metasurfaces.