Sub-micrometer chemical imaging of dental adhesive/dentin interfaces via mid-infrared photothermal microscopy Author links open overlay panel


地方国立大学の定員増における新教育組織の設置に伴う入口戦略としての入試制度設計と実施――徳島大学 MPEプログラムを例として――

The Journal of University Admissions Research


Fabrication of Mie-resonant silicon nanoparticles using laser annealing for surface-enhanced fluorescence spectroscopy

Silicon nanostructures with unique Mie resonances have garnered considerable attention in the field of nanophotonics. Here, we present a simple and efficient method for the fabrication of silicon (Si) nanoparticle substrates using continuous-wave (CW) laser annealing. The resulting silicon nanoparticles exhibit Mie resonances in the visible region, and their resonant wavelengths can be precisely controlled. Notably, laser-annealed silicon nanoparticle substrates show a 60-fold enhancement in fluorescence. This tunable and fluorescence-enhancing silicon nanoparticle platform has tremendous potential for highly sensitive fluorescence sensing and biomedical imaging applications.


Mid-Infrared Photothermal Imaging of Photochemically Patterned Polymer Gate Dielectrics for Organic Thin-Film Transistors


Label-free visualization of photosynthetic microbial biofilms using mid-infrared photothermal and autofluorescence imaging

The formation of photosynthetic microbial biofilms comprising multispecies biomolecules, such as extracellular polymeric substances (EPSs), and microbial cells play pivotal roles in maintaining or stimulating their biological functions. Although there are numerous studies on photosynthetic microbial biofilms, the spatial distribution of EPS components that are vital for microbial biofilm formation, such as exopolysaccharides and proteins, is not well understood. Visualization of photosynthetic microbial biofilms requires label-free methods, because labelling EPSs results in structural changes or aggregation. Raman spectroscopy is useful for label-free visualization of biofilm constituents based on chemical contrast. However, interference resulting from the bright autofluorescence of photosynthetic molecules and the low detection efficiency of Raman scattering make visualization a challenge. Herein, we visualized photosynthetic microbial biofilms in a label-free manner using a super-resolution optical infrared absorption imaging technique, called mid-infrared photothermal (MIP) microscopy. By leveraging the advantages of MIP microscopy, such as its sub-micrometer spatial resolution, autofluorescence-free features, and high detection sensitivity, the distribution of cyanobacteria and their extracellular polysaccharides in the biofilm matrix were successfully visualized. This showed that cyanobacterial cells were aligned along acidic/sulfated polysaccharides in the extracellular environment. Furthermore, spectroscopic analyses elucidated that during formation of biofilms, sulfated polysaccharides initially form linear structures followed by entrapment of cyanobacterial cells. The present study provides the foundation for further studies on the formation, structure, and biological functions of microbial biofilms.


Real-time hybrid angular-interrogation surface plasmon resonance sensor in the near-infrared region for wide dynamic range refractive index sensing


センシング応用へ向けたメタマテリアル内電場分布の振動分光計測

センシング応用へ向けたメタマテリアル内電場分布の振動分光計測


Tungsten suboxide (WO3x) petal-like nanosheets created by laser ablation method


Single-cell infrared vibrational analysis by optical trapping mid-infrared photothermal microscopy

Single-cell analysis by means of vibrational spectroscopy combined with optical trapping is a reliable platform for unveiling cell-to-cell heterogeneities in vast populations. Although infrared (IR) vibrational spectroscopy provides rich molecular fingerprint information on biological samples in a label-free manner, its application with optical trapping has never been achieved due to weak gradient forces generated by the diffraction-limited focused IR beam and strong background of water absorption. Herein, we present single-cell IR vibrational analysis that incorporates mid-infrared photothermal (MIP) microscopy with optical trapping. Optically trapped single polymer particles and red blood cells (RBCs) in blood could be chemically identified owing to their IR vibrational fingerprints. This single-cell IR vibrational analysis further allowed us to probe the chemical heterogeneities of RBCs originating from the variation in the intracellular characteristics. Our demonstration paves the way for the IR vibrational analysis of single cells and chemical characterization in various fields.


Highly sensitive detection of nucleocapsid protein from SARS-CoV-2 using a near-infrared surface plasmon resonance sensing system


High-sensitivity hyperspectral vibrational imaging of heart tissues by mid-infrared photothermal microscopy

Visualizing the spatial distribution of chemical compositions in biological tissues is of great importance to study fundamental biological processes and origin of diseases. Raman microscopy, one of the label-free vibrational imaging techniques, has been employed for chemical characterization of tissues. However, the low sensitivity of Raman spectroscopy often requires a long acquisition time of Raman measurement or a high laser power, or both, which prevents one from investigating large-area tissues in a nondestructive manner. In this work, we demonstrated chemical imaging of heart tissues using mid-infrared photothermal (MIP) microscopy that simultaneously achieves the high sensitivity benefited from IR absorption of molecules and the high spatial resolution down to a few micrometers. We successfully visualized the distributions of different biomolecules, including proteins, phosphate-including proteins, and lipids/carbohydrates/amino acids. Further, we experimentally compared MIP microscopy with Raman microscopy to evaluate the sensitivity and photodamage to tissues. We proved that MIP microscopy is a highly sensitive technique for obtaining vibrational information of molecules in a broad fingerprint region, thereby it could be employed for biological and diagnostic applications, such as live-tissue imaging.


Ultrastable tip-enhanced hyperspectral optical nano-imaging for defect analysis of large-sized WS2 layers


Beam-angle-scanning surface plasmon resonance sensor for rapid, high-precision sensing of refractive index and bio-molecules


Ultrasensitive detection of SARS-CoV-2 nucleocapsid protein using large gold nanoparticle-enhanced surface plasmon resonance.

The COVID-19 pandemic has created urgent demand for rapid detection of the SARS-CoV-2 coronavirus. Herein, we report highly sensitive detection of SARS-CoV-2 nucleocapsid protein (N protein) using nanoparticle-enhanced surface plasmon resonance (SPR) techniques. A crucial plasmonic role in significantly enhancing the limit of detection (LOD) is revealed for exceptionally large gold nanoparticles (AuNPs) with diameters of hundreds of nm. SPR enhanced by these large nanoparticles lowered the LOD of SARS-CoV-2 N protein to 85 fM, resulting in the highest SPR detection sensitivity ever obtained for SARS-CoV-2 N protein.


Highly Stable Polymer Coating on Silver Nanoparticles for Efficient Plasmonic Enhancement of Fluorescence


Multi-modal vibrational analysis of blend polymers using mid-infrared photothermal and Raman microscopies


Electrochemically induced metal- vs. ligand-based redox changes in mackinawite: identification of a Fe3+- and polysulfide-containing intermediate


JRAB/MICAL-L2 undergoes liquid-liquid phase separation to form tubular recycling endosomes.

Elongated tubular endosomes play essential roles in diverse cellular functions. Multiple molecules have been implicated in tubulation of recycling endosomes, but the mechanism of endosomal tubule biogenesis has remained unclear. In this study, we found that JRAB/MICAL-L2 induces endosomal tubulation via activated Rab8A. In association with Rab8A, JRAB/MICAL-L2 adopts its closed form, which functions in the tubulation of recycling endosomes. Moreover, JRAB/MICAL-L2 induces liquid-liquid phase separation, initiating the formation of tubular recycling endosomes upon overexpression. Between its N-terminal and C-terminal globular domains, JRAB/MICAL-L2 contains an intrinsically disordered region, which contributes to the formation of JRAB/MICAL-L2 condensates. Based on our findings, we propose that JRAB/MICAL-L2 plays two sequential roles in the biogenesis of tubular recycling endosomes: first, JRAB/MICAL-L2 organizes phase separation, and then the closed form of JRAB/MICAL-L2 formed by interaction with Rab8A promotes endosomal tubulation.


Comparison of hot carrier generation between self-assembled gold and silver nanoparticle arrays tailored to the same hybrid plasmon resonance


Unbinding events of amino acids and peptides from waterpyrite interfaces: A case study of lifes origin on mineral surfaces


高屈折率誘電体ナノ粒子のナノフォトニクス

高屈折率誘電体ナノ粒子のナノフォトニクス


Selection and Visualization of Degenerate Magnetic and Electric Multipoles up to Radial Higher Orders by Cathodoluminescence


Experimental and theoretical elucidation of catalytic pathways in TiO2-initiated prebiotic polymerization

The tendency of glycine to form polymer chains on a rutile(110) surface under wet/dry conditions (dry-wet cycles at high temperature) is studied through a conjunction of surface sensitive experimental techniques and sequential periodic multilevel calculations that mimics the experimental procedures with models of decreasing complexity and increasing accuracy. X-ray photoemission spectroscopy (XPS) and thermal desorption spectroscopy (TDS) experimentally confirmed that the dry-wet cycles lead to Gly polymerization on the oxide support. This was supported by all the theoretical characterizations. First, classical reactive molecular dynamics (MD) simulations based on the ReaxFF approach were used to reproduce the adsorption of the experimental glycine solution droplets sprayed onto an oxide support and to identify the most probable arrangement of the molecules that triggered the polymerization mechanisms. Then, quantum chemistry density functional tight binding (DF-TB) MDs and static density functional theory (DFT) calculations were carried out to further explore favorable configurations and to evaluate the energy barriers of the most promising reaction pathways for the peptide bond-formation reactions. The results confirmed the fundamental role played by the substrate to thermodynamically and kinetically favor the process and disclosed its main function as an immobilizing agent: the molecules accommodated in the surface channels close to each other were the ones starting the key events of the dimerization process and the most favorable mechanism was the one where a water molecule acted as a proton exchange mediator in the condensation process.


Tip-enhanced Raman scattering microscopy: A step toward nanoscale control of intrinsic molecular properties

Journal of the Physical Society of Japan


Size-dependent affinity of glycine and its short oligomers to pyrite surface: a model for prebiotic accumulation of amino acid oligomers on a mineral surface

The interaction strength of progressively longer oligomers of glycine, (Gly), di-Gly, tri-Gly, and penta-Gly, with a natural pyrite surface was directly measured using the force mode of an atomic force microscope (AFM). In recent years, selective activation of abiotically formed amino acids on mineral surfaces, especially that of pyrite, has been proposed as an important step in many origins of life scenarios. To investigate such notions, we used AFM-based force measurements to probe possible non-covalent interactions between pyrite and amino acids, starting from the simplest amino acid, Gly. Although Gly itself interacted with the pyrite surface only weakly, progressively larger unbinding forces and binding frequencies were obtained using oligomers from di-Gly to penta-Gly. In addition to an expected increase of the configurational entropy and size-dependent van der Waals force, the increasing number of polar peptide bonds, among others, may be responsible for this observation. The effect of chain length was also investigated by performing similar experiments using l-lysine vs. poly-l-lysine (PLL), and l-glutamic acid vs. poly-l-glutamic acid. The results suggest that longer oligomers/polymers of amino acids can be preferentially adsorbed on pyrite surfaces.

International Journal of Molecular Sciences


Composite Sulfur Electrode for All-Solid-State Lithium-Sulfur Battery with Li2S-GeS2-P2S5-Based Thio-LISICON Solid Electrolyte


Cysteine and cystine adsorption on FeS2(100)


Surface force analysis of glycine adsorption on different crystal surfaces of titanium dioxide (TiO2)


Composite Sulfur Electrode Prepared by High-Temperature Mechanical Milling for use in an All-Solid-State Lithium-Sulfur Battery with a Li3.25Ge0.25P0.75S4 Electrolyte


Damage-Free Tip-Enhanced Raman Spectroscopy for Heat-Sensitive Materials


Raman imaging analysis of local crystal structures in LiCoO2 thin films calcined at different temperature


Nanoscale optical imaging of lithium-ion distribution on a LiCoO2 cathode surface


Effect of Excess Li2S on Electrochemical Properties of Amorphous Li3PS4 Films Synthesized by Pulsed Laser Deposition


Highly sensitive SERS analysis of the cyclic Arg-Gly-Asp peptide ligands of cells using nanogap antennas

The cyclic RGD (cRGD) peptide ligands of cells have become widely used for treating several cancers. We report a highly sensitive analysis of c(RGDfC) using surface enhanced Raman spectroscopy (SERS) using single dimer nanogap antennas in aqueous environment. Good agreement between characteristic peaks of the SERS and the Raman spectra of bulk c(RGDfC) with its peptide's constituents were observed. The exhibited blinking of the SERS spectra and synchronization of intensity fluctuations, suggest that the SERS spectra acquired from single dimer nanogap antennas was dominated by the spectrum of single to a few molecules. SERS spectra of c(RGDfC) could be used to detect at the nanoscale, the cells' transmembrane proteins binding to its ligand. SERS of cyclic RGD on nanogap antenna.


Enhanced optical magnetism for reversed optical binding forces between silicon nanoparticles in the visible region

We perform a comprehensive numerical analysis on the optical binding forces of a multiple-resonant silicon nanodimer induced by the normal illumination of a plane wave in the visible region. The silicon nanodimer provides either repulsive or attractive forces in water while providing only attractive forces in air. The enhancement of the magnetic dipole mode is attributed to the generation of repulsive forces. The sign (attractive/repulsive) and the amplitude of the optical forces are controlled by incident polarization and separation distance between the silicon nanoparticles. These optomechanical effects demonstrate a key step toward the optical sorting and assembly of silicon nanoparticles.


Dynamics of Strong Coupling between CdSe Quantum Dots and Surface Plasmon Polaritons in Subwavelength Hole Array

The Journal of Physical Chemistry Letters


Oxygen substitution effects in Li10GeP2S12 solid electrolyte


Laser Scanning Assisted Tip-Enhanced Optical Microscopy for Robust Optical Nanospectroscopy


Surface force analysis of pyrite (FeS2): its reactivity to amino acid adsorption

Advances in Materials Physics and Chemistry


Fano resonant all-dielectric core/shell nanoparticles with ultrahigh scattering directionality in the visible region


Laser-induced electrochemical thinning of MoS2

Journal of Materials Chemistry. C, Materials for Optical and Electronic Devices


Tip-enhanced THz Raman spectroscopy for local temperature determination at the nanoscale


Probing edge-activated resonant Raman scattering from mechanically exfoliated 2D MoO3 nanolayers


Controlling the Visible Electromagnetic Resonances of Si/SiO2 Dielectric Core-Shell Nanoparticles by Thermal Oxidation


Spectral tunability of realistic plasmonic nanoantennas


Effect of the distribution of adsorbed proteins on cellular adhesion behaviors using surfaces of nanoscale phase-reversed amphiphilic block copolymers


Light-transmittable Ultrasmooth Gold Film for Gap-mode Tip-enhanced Raman Scattering Spectroscopy


Tip-enhanced nano-Raman analytical imaging of locally induced strain distribution in carbon nanotubes


Metal nanoparticles for nano-imaging and nano-analysis


Highly reproducible tip-enhanced Raman scattering using an oxidized and metallized silicon tip as a tool for everyone


Subnanometric stabilization of plasmon-enhanced optical microscopy


Fabrication of near-field plasmonic tip by photoreduction for strong enhancement in tip-enhanced Raman spectroscopy


Tip-heating-assisted Raman spectroscopy at elevated temperatures


Nano-imaging through tip-enhanced Raman spectroscopy: Stepping beyond the classical limits


Experimental Identification of Chemical Effects in Surface Enhanced Raman Scattering of 4-Aminothiophenol


Pressure-assisted tip-enhanced Raman imaging at a resolution of a few nanometers


Subnanometric Near-Field Raman Investigation in the Vicinity of a Metallic Nanostructure


Confinement of enhanced field investigated by tip-sample gap regulation in tapping-mode tip-enhanced Raman microscopy


Nanoscale uniaxial pressure effect of a carbon nanotube bundle on tip-enhanced near field Raman spectra

In situ measurement of tip-enhanced near-field Raman spectra of an isolated single-wall carbon nanotube (SWNT) bundle has been demonstrated by applying a uniaxial pressure up to approximately 2 GPa to the bundle via a metal-coated atomic force microscope tip. We investigated the pressure dependences of Raman frequencies and the intensity of the radial breathing mode bands, the D-band and the G-band, which were related to deformation of SWNTs caused by the tip pressure.


Diameter-selective near-field Raman analysis and imaging of isolated carbon nanotube bundles


カーボンナノチューブの近接場ナノラマン分光分析

カーボンナノチューブの近接場ナノラマン分光分析


Detection of an individual single-wall carbon nanotube by tip-enhanced near-field Raman spectroscopy