Elucidating Interplay of Chemical and Metal Interface Damping in Single Gold Nanorods Coated with an Ultrathin Palladium Shell.

Understanding plasmon damping pathways in gold nanoparticles is crucial for its efficient utilization in photochemical processes and biosensing experiments. However, elucidating the competition and interplay between chemical and metal interface damping pathways remains a significant challenge. Herein, we investigate the plasmon decay pathways of thiolated ultrathin palladium (Pd)-coated gold nanorods (AuNRs@Pd) by using dark-field (DF) spectroscopy and surface-enhanced Raman spectroscopy (SERS).

Single-Particle Spectroelectrochemistry: Revealing the Electrochemical Tuning Mechanism of Chemical Interface Damping in 1,2-Benzenedithiol-Adsorbed Single Gold Nanorods.

Chemical interface damping (CID) is a newly proposed plasmon damping pathway based on interfacial hot-electron transfer from metal to adsorbate molecules. However, achieving tunability of CID in single gold nanorods (AuNRs) remains a considerable challenge. Here, we present the CID effect induced by benzene 1,2-dithiol (BDT) molecule adsorption on single AuNRs and the effective electrochemical tunability of CID in BDT-adsorbed AuNRs immobilized on an indium tin oxide (ITO) surface.

Elucidating refractive index sensitivity on subradiant, superradiant, and fano resonance modes in single palladium-coated gold nanorods.

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.

In Situ Photoreversible Tuning of Chemical Interface Damping in Single Gold Nanorods Through Cucurbit[8]uril-Based Host-Guest Interactions.

Chemical interface damping (CID) is a recently proposed plasmon-damping pathway based on the interfacial hot-electron transfer from metal to adsorbate molecules. However, the in situ reversible tuning of CID in single gold nanorods (AuNRs) has remained a considerable challenge. In this study, we used total internal reflection scattering microscopy and spectroscopy to investigate the CID induced by -aminoazobenzene (-AAB), which has fast photoisomerization characteristics, attached to single AuNRs.

Tuning of chemical interface damping in single gold nanorods through pH-dependent host-guest interactions using cucurbit[6]uril.

Chemical interface damping (CID) in gold nanorods (AuNRs) arises from direct hot electron transfer from Au to adsorbed molecules. Despite recent studies on CID, its tunability in single AuNRs remains challenging. Herein, we present a method for control of CID in single AuNRs using pH-dependent host-guest supramolecular interactions.

Single-Particle Spectroelectrochemistry: Promoting the Electrocatalytic Activity of Gold Nanorods via Oxygen Plasma Treatment without Structural Deformation.

Understanding of the electrocatalytic activity enhancement in gold nanoparticles is still limited. Herein, we present the effect of the oxygen plasma treatment on the electrochemical activity of gold nanorods (AuNRs). Oxygen plasma treatment resulted in the blueshift and line width narrowing of the localized surface plasmon resonance (LSPR) spectra obtained from individual AuNRs immobilized on an indium tin oxide (ITO) surface.

Direct Observation of Plasmonic Cargos Breaking Angular Degeneracy in Differential Interference Contrast Microscopy.

Breaking the angular degeneracy arising from the 2-fold optical symmetry of plasmonic anisotropic nanoprobes is critical in biological studies. In this study, we propose differential interference contrast (DIC) microscopy-based focused orientation and position imaging (dFOPI) to break the angular degeneracy of single gold nanorods (AuNRs). Single AuNRs (39 nm × 123 nm) within a spherical mesoporous silica shell were characterized with high throughput and produced distinct doughnut-shaped DIC image patterns featuring two lobes in the peripheral region, attributed to the scattering contribution of the AuNRs with large scattering cross sections.

Tuning Chemical Interface Damping: Competition between Surface Damping Pathways in Amalgamated Gold Nanorods Coated with Mesoporous Silica Shells.

The mechanism of mercury (Hg) amalgamation in gold nanorods coated with a mesoporous silica shell (AuNRs@SiO) and the effect of chemical treatments on the localized surface plasmon resonance (LSPR) spectral changes in single amalgamated AuNRs@SiO remains unclear. In this study, we investigated Hg amalgamation and inward Hg diffusion in single AuNRs@SiO without structural deformation via dark-field scattering spectroscopy and X-ray photoelectron spectroscopy. Then, we investigated the chemisorption of thiol molecules on single amalgamated AuNRs@Hg-SiO.

Burst of hopping trafficking correlated reversible dynamic interactions between lipid droplets and mitochondria under starvation.

Dynamic membrane contacts between lipid droplets (LDs) and mitochondria play key roles in lipid metabolism and energy homeostasis. Understanding the dynamics of LDs under energy stimulation is thereby crucial to disclosing the metabolic mechanism. Here, the reversible interactions between LDs and mitochondria are tracked in real-time using a robust LDs-specific fluorescent probe (LDs-Tags).

Elucidating Surface Plasmon Damping and Fano Resonance Induced by Epitaxial Growth of Palladium on Single Gold Nanorods.

Plasmon damping and Fano resonance induced in the growth of palladium (Pd) on gold nanorods (AuNRs) have been poorly understood. Herein, we investigated the optical properties and morphologies of single AuNRs@Pd (core@shell) synthesized using epitaxial Pd growth at different Pd concentrations. The localized surface plasmon resonance (LSPR) spectra of single AuNRs@Pd showed characteristic subradiant and superradiant peaks as well as Fano resonance as a spectral dip, which was highly influenced by the Pd shell thickness.

reversible tuning of chemical interface damping in mesoporous silica-coated gold nanorods direct adsorption and removal of thiol.

Chemical interface damping (CID) is a recently proposed plasmon decay channel in gold nanoparticles. However, thus far, a very limited number of studies have focused on controlling CID in single gold nanoparticles. Herein, we describe a new simple method for reversible tuning of CID in single gold nanorods coated with a mesoporous silica shell (AuNRs@mSiO).

Single-Particle Spectroelectrochemistry: Electrochemical Approaches for Tuning Chemical Interfaces and Plasmon Damping in Single Gold Nanorods.

The strong adsorption of thiol molecules on gold nanorods (AuNRs) results in localized surface plasmon resonance (LSPR) energy loss chemical interface damping (CID). This study investigated the CID effect induced by thiophenol (TP) adsorption on single AuNRs and the tuning of LSPR properties and chemical interfaces through electrochemical potential manipulation. The potential-dependent LSPR spectrum of bare AuNRs exhibited redshifts and line width broadening owing to the characteristics of capacitive charging, Au oxidation, and oxidation dissolution.

Bioactive Phytochemicals from Twigs: Anti-Adipogenic Effect of 2'--Acetylsalicortin in 3T3-L1 Cells.

(Salicaceae) is a willow tree and has been used as a medicinal herb in Korea to treat pain and fever. As a part of an ongoing study to identify bioactive natural products, potential anti-adipogenic compounds were investigated using the ethanol (EtOH) extract of twigs. Phytochemical investigation of the EtOH extracts using liquid chromatography-mass spectrometry (LC/MS) led to the separation of two compounds, oregonin () and 2'--acetylsalicortin ().

Antitumor Potential of Withanolide Glycosides from Ashwagandha () on Apoptosis of Human Hepatocellular Carcinoma Cells and Tube Formation in Human Umbilical Vein Endothelial Cells.

Hepatocellular carcinoma (HCC) is the fastest-growing tumor capable of spreading to other organs via blood vessels formed by endothelial cells. Apoptosis and angiogenesis-targeting therapies are attractive for cancer treatment. In this study, we aimed to study the in vitro cytotoxicity of against human HCC (HepG2) cells, identify potential antitumoral withanolide glycosides from the active fraction, and elucidate cytotoxic molecular mechanisms of identified bioactive compounds.

Tuning plasmonic properties by promoting the inward Hg diffusion oxygen plasma treatment in gold nanorods coated with a mesoporous silica shell.

This paper describes a new strategy using oxygen plasma treatment to tune the localized surface plasmon resonance (LSPR) of gold nanorods coated with a mesoporous silica shell (AuNRs@SiO) exposed to mercury (Hg) solution. Dark-field (DF) microscopy and spectroscopy were used to reveal the effects of oxygen plasma treatment on the structural and LSPR spectral changes of single amalgamated AuNRs@SiO. Due to the structural stability provided by the mesoporous silica shell, the amalgamated AuNRs@SiO exposed to oxygen plasma treatment showed no morphological transformation.

Influence of oxygen plasma treatment on structural and spectral changes in gold nanorods immobilized on indium tin oxide surfaces.

Oxygen plasma treatment is commonly used to sterilize gold nanoparticles by removing chemical contaminants from their surface while simultaneously inducing surface activation and functionalization of nanoparticles for biological, electrocatalytic, or electrochemical studies. In this study, we investigate the influence of oxygen plasma treatment on structural and localized surface plasmon resonance (LSPR) spectral changes of anisotropic gold nanorods (AuNRs) immobilized on an indium tin oxide (ITO) glass substrate. Unlike AuNRs deposited on a glass slide, no noticeable structural change or deformation of AuNRs on ITO was observed while increasing the oxygen plasma treatment time.

Retraction: Single gold nanostars with multiple branches as multispectral orientation probes in single-particle rotational tracking.

Retraction of 'Single gold nanostars with multiple branches as multispectral orientation probes in single-particle rotational tracking' by Geun Wan Kim , , 2021, , 3263-3266, https://doi.org/10.1039/D1CC00731A.

Effects of Amine Linkers with Different Carbon Chain Lengths at Guanine-Rich Polynucleotides on Chemical Interface Damping in Single Gold Nanorods.

DNA-functionalized gold nanoparticles (AuNPs) are used for various bioapplications, such as biosensor development and drug delivery. Nevertheless, no study has reported the effect of polynucleotide chains on chemical interface damping (CID), the most recently proposed plasmon damping pathway in single AuNPs. In this study, we conducted total internal reflection scattering measurements of gold nanorods (AuNRs) to reveal the CID effect induced by amine (NH)-linked polynucleotides (or DNA) with guanine-rich sequences through the interaction between nitrogen and Au surfaces.

Single-particle spectroelectrochemistry: electrochemical tuning of plasmonic properties mercury amalgamation in mesoporous silica coated gold nanorods without structural deformation.

This paper elucidates the mercury (Hg) amalgamation induced by electrochemical reduction on gold nanorods coated with mesoporous silica shell (AuNRs@mSiO) using single-particle spectroelectrochemistry. First, the silica shell significantly enhanced the structural stability of AuNR cores after Hg amalgamation with the application of linear sweep voltages (LSVs). Thus, we were able to focus on the spectral changes of AuNRs@mSiO induced by the deposition of Hg without the disturbance of structural deformation, which also strongly affects localized surface plasmon resonance (LSPR) properties.

Mesoporous silica shell-coated single gold nanorods as multifunctional orientation probes in dynamic biological environments.

Mesoporous silica shell-coated gold nanorods (AuNRs@mSiO) can be employed as promising multifunctional orientation probes in biological studies owing to their anisotropic optical properties, enhanced stability, excellent biocompatibility, In this study, the optical properties of single AuNRs@mSiO are characterized under dark-field and differential interference contrast (DIC) microscopy. Furthermore, we presented polarization-dependent, periodic DIC images and intensities of single AuNRs@mSiO at their localized surface plasmon resonance wavelength and investigated their use as multifunctional orientation probes in dynamic biological environments. Moreover, the real-time rotational motions of the AuNRs@mSiO on the HeLa cell membranes were tracked with millisecond temporal resolution.

Enhanced refractive index sensitivity of localized surface plasmon resonance inflection points in single hollow gold nanospheres with inner cavity.

Hollow gold nanoparticles have great potential for localized surface plasmon resonance (LSPR) sensing. In this study, we investigated the refractive index (RI) sensitivities of single hollow gold nanosphere (HAuNS) with thin Au shell and inner cavity and single solid gold nanosphere (AuNS) in media with different RIs. The HAuNS exhibited a remarkable improvement in the RI sensitivity than the AuNS of similar size.

Structural Characterization of Withanolide Glycosides from the Roots of and Their Potential Biological Activities.

(Solanaceae), commonly known as "ashwagandha", is an ayurvedic medicinal plant that has been used for promoting good health and longevity. As part of our ongoing natural product research for the discovery of bioactive phytochemicals with novel structures, we conducted a phytochemical analysis of root, commonly used as an herbal medicine part. The phytochemical investigation aided by liquid chromatography-mass spectrometry (LC/MS)-based analysis led to the isolation of four withanolide glycosides (-), including one new compound, withanoside XII (), from the methanol (MeOH) extract of root.

Single-Particle Study on Hg Amalgamation Mechanism and Slow Inward Diffusion in Mesoporous Silica-Coated Gold Nanorods without Structural Deformation.

This paper presents the structural and spectral variations of individual mesoporous silica-coated gold nanorods (AuNRs@mSiO) compared to bare AuNRs upon Hg-Au amalgamation. First, the aspect ratio of AuNRs@mSiO exposed to Hg solutions was unchanged because the deformation related to the cores of AuNR was suppressed by the silica shell. Second, dark-field microscopy and spectroscopy revealed a blue shift of the localized surface plasmon resonance (LSPR) wavelength peak and strong plasmon damping in the individual AuNRs@mSiO scattering spectra, exposed to Hg solutions.