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Focused ion beam (FIB) is widely used for thinning frozen cells to produce lamellae for cryo-electron microscopy imaging and for protein structures study in vivo. However, FIB damages the lamellae and a quantitative experimental analysis of the damage is lacking. We used a 30-keV gallium FIB to prepare lamellae of a highly concentrated icosahedral virus sample. The viruses were grouped according to their distance from the surface of lamellae and reconstructed. Damage to the approximately 20-nm-thick outermost lamella surface was similar to that from exposure to 16 e/Å in a 300-kV cryo-electron microscope at high-resolution range. The damage was negligible at a depth beyond 50 nm, which was reduced to 30 nm if 8-keV Ga was used during polishing. We designed extra steps in the reconstruction refinement to maximize undamaged signals and increase the resolution. The results demonstrated that low-energy beam polishing was essential for high-quality thinner lamellae.
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http://dx.doi.org/10.1016/j.str.2023.07.002 | DOI Listing |
ACS Appl Mater Interfaces
September 2025
College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, P. R. China.
Exhaled breath analysis offers noninvasive, early lung cancer detection via volatile organic compound (VOC) biomarkers, surpassing blood-based methods. Surface-enhanced Raman spectroscopy (SERS) is ideal for this purpose, combining molecular fingerprint specificity with single-molecule sensitivity. However, conventional SERS substrates face a fundamental limitation: while porous materials such as metal-organic frameworks effectively adsorb VOCs through their subnanometer pores (0.
View Article and Find Full Text PDFAnal Chem
September 2025
Department of Chemistry, Southern University of Science and Technology, 518055 Shenzhen, China.
Electrochemiluminescence (ECL) imaging through closed bipolar nanoelectrode arrays (BPnEAs) has emerged as a promising method for in situ label-free wide-field electrochemical imaging. In this study, a cathodic ECL system based on [Ru(bpz)]/SO is combined with the BPnEAs fabricated on silicon nitride membrane windows through focused ion beam nanofabrication, enabling effective bipolar imaging of heterogeneous anodic electrocatalytic reactions. The shape, distribution, size, and material composition of individual electrodes within the array can be precisely controlled.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2025
Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel.
We applied micro-computed tomography, high-resolution cryo-scanning electron microscopy (SEM) combined with cathodoluminescence, and cryo-focused ion beam Milling-SEM to perform three-dimensional imaging of human atherosclerotic tissues with tens of nanometers resolution, under hydrated, near-native conditions with minimal sample processing. The same technology was applied to cultured macrophages exposed to cholesterol crystals, and the observations made on the macrophages were compared to those made on the pathological tissue. We observed that cholesterol crystal digestion and, eventually, cholesterol crystal clearance occurs in the advanced human plaques through cellular processing.
View Article and Find Full Text PDFRev Sci Instrum
September 2025
Instituut voor Kern-en Stalingsfysica, KU Leuven, Leuven, Belgium.
We present two newly constructed experimental setups-REBEL (Resonant Excitation of Beams with Electromagnetic fields and Lasers) and STRIPE (Stopping and Trapping of Radioactive Isotopes for Precision Experiments)-integrated into a single offline beamline at KU Leuven. REBEL is designed for collinear laser spectroscopy of ion bunches, including isobaric separation with a multi-reflection time-of-flight mass spectrometer, enabling high-sensitivity measurements of mass-selected fast-ion beams. In contrast, STRIPE focuses on the deceleration, trapping, and laser cooling of ions in a segmented linear Paul trap, optimized for long interrogation times and precision spectroscopy.
View Article and Find Full Text PDFParallelization has revolutionized computing and DNA sequencing but remains largely unexploited in mass spectrometry (MS), which typically analyzes ions sequentially. We introduce a nature-inspired ion trap (MultiQ-IT) that enables massively parallel MS. The device comprises a cubic array of small quadrupoles forming multiple ion entry and exit ports, allowing >10⁹ ions to be confined and manipulated simultaneously.
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