Spatially resolved electron energy loss spectroscopy (SR-EELS) using scanning transmission electron microscope (STEM) allows the identification and determination of the spatial distribution of the components/elements of immuno-functionalized core-shell superparamagnetic magnetite nanoparticles. Here, we report that SR-EELS measurements allow the direct identification and study of the biological moieties (protein G and anti-HRP antibody) in complex bionanocarriers of relevance for biomedical applications. Our findings show that the biomacromolecules are located on specific areas on the nanoparticles' surface. In addition, efficiency of this functionalization was evaluated by means of biochemical techniques.
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http://dx.doi.org/10.1021/nn306028t | DOI Listing |
Anal Chem
August 2024
Center for Research Equipment, Korea Basic Science Institute, Daejeon 34133, Republic of Korea.
Electron energy-loss spectroscopy (EELS) is widely used in analyzing the electronic structure of inorganic materials at high spatial resolution. In this study, we use a monochromator to improve the energy resolution, allowing us to analyze the electronic structure of organic light-emitting diode (OLED) materials with greater precision. This study demonstrates the use of the energy-loss near-edge structure to map the nitrogen content of organic molecules and identify the distinct bonding characteristics of aromatic carbon and pyridinic nitrogen.
View Article and Find Full Text PDFACS Nano
June 2024
the Barcelona Institute of Science and Technology, ICFO-Institut de Ciencies Fotoniques, Castelldefels, Barcelona 08860, Spain.
Narrow gaps between plasmon-supporting materials can confine infrared electromagnetic energy at the nanoscale, thus enabling applications in areas such as optical sensing. However, in nanoparticle dimers, the nature of the transition between touching (zero gap) and nearly nontouching (nonzero gap ≲15 nm) regimes is still a subject of debate. Here, we observe both singular and nonsingular transitions in infrared plasmons confined to dimers of fluorine-doped indium oxide nanocubes when moving from touching to nontouching configurations depending on the dimensionality of the contact region.
View Article and Find Full Text PDFACS Nano
April 2024
Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France.
We report on the design, realization, and experimental investigation by spatially resolved monochromated electron energy loss spectroscopy (EELS) of high-quality-factor cavities with modal volumes smaller than λ, with λ being the free-space wavelength of light. The cavities are based on a slot defect in a 2D photonic crystal slab made up of silicon. They are optimized for high coupling of electrons accelerated to 100 kV to quasi-transverse electrical modes polarized along the slot direction.
View Article and Find Full Text PDFUltramicroscopy
December 2023
Kavli Institute of Nanoscience, Delft University of Technology, Delft, 2628 CJ, The Netherlands. Electronic address:
Among the many potential applications of topological insulator materials, their broad potential for the development of novel tunable plasmonics at THz and mid-infrared frequencies for quantum computing, terahertz detectors, and spintronic devices is particularly attractive. The required understanding of the intricate relationship between nanoscale crystal structure and the properties of the resulting plasmonic resonances remains, however, elusive for these materials. Specifically, edge- and surface-induced plasmonic resonances, and other collective excitations, are often buried beneath the continuum of electronic transitions, making it difficult to isolate and interpret these signals using techniques such as electron energy-loss spectroscopy (EELS).
View Article and Find Full Text PDFMicroscopy (Oxf)
February 2024
Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
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