Microscopy Resolution Research Articles

METHOD FOR INCREASING THE RESOLVING POWER OF AN OPTICAL MICROSCOPE

Purpose. Increasing the resolution and magnification of the optical microscope to expand the possibilities of observation and research in various fields of science and technology. Research methods. Theoretical, experimental. Results. A comparative analysis of the human eye as an optical system and the optical system of a microscope was carried out. It was found that these systems have a similar nature, namely, a separate image of two closely located objects. If we consider the human eye as a light-sensitive matrix, then to determine the resolution of the eye, it is necessary to use the ratio of the average value of the number of light-sensitive elements (rods and cones) that fall on the retina to the area of the retina itself (for the human eye, it is 0.1...0.2 mm). For an optical microscope, it is necessary to separate the concepts of “resolution” and “magnification”. We also mentioned the physical basis of the resolution of optical microscopes. It was shown that for a dry lens the resolution limit for λ = 555 nm is 0.3 μm. One of the ways to increase the resolution is the use of immersion fluids. However, in certain studies its use is inappropriate or impossible. If instead of conventional illuminators (maximum intensity at λ = 555 nm) you use ultraviolet ones (λ = 380…410 nm), then the resolution can be increased several times, and the increase is up to 2000. The disadvantage of using UV illuminators is that it is necessary to use a light filter with direct observation or a monitor with an indirect method to avoid negative effects on the observer’s vision. Scientific novelty. The increased resolution and magnification of the optical microscope when using coherent light sources instead of immersion fluids provides more detailed scientific information and facilitates its processing. Practical value. Using the results of our research allows you to get a more informative image when using coherent light sources.

Large-scale simulations of vortex Majorana zero modes in topological crystalline insulators

Topological crystalline insulators are known to support multiple Majorana zero modes (MZMs) at a single vortex, their hybridization is forbidden by a magnetic mirror symmetry MT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$M_{T}$\\end{document}. Due to the limited energy resolution of scanning tunneling microscopes and the very small energy spacing of trivial bound states, it remains challenging to directly probe and demonstrate the existence of multiple MZMs. In this work, we propose to demonstrate the existence of MZMs by studying the hybridization of multiple MZMs in a symmetry breaking field. The different responses of trivial bound states and MZMs can be inferred from their spatial distribution in a vortex. However, the theoretical simulations are very demanding since it requires an extremely large system in real space. By utilizing the kernel polynomial method, we can efficiently simulate large lattices with over 108 orbitals to compute the local density of states which bridges the gap between theoretical studies based on minimal models and experimental measurements. We show that the spatial distribution of MZMs and trivial vortex bound states differs drastically in tilted magnetic fields. The zero-bias peak elongates when the magnetic field preserves MT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$M_{T}$\\end{document}, while it splits when MT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$M_{T}$\\end{document} is broken, giving rise to an anisotropic magnetic response. Since the bulk of SnTe are metallic, we also study the robustness of MZMs against the bulk states, and clarify when can the MZMs produce a pronounced anisotropic magnetic response.

Accuracy of the LaserSAFE technique for detecting positive surgical margins during robot-assisted radical prostatectomy: blind assessment and inter-rater agreement analysis.

Fluorescence confocal microscopy (FCM) is a new imaging modality capable of generating digital microscopic resolution scans of fresh surgical specimens, and holds potential as an alternative to frozen section (FS) analysis for intra-operative assessment of surgical margins. Previously, we described the LaserSAFE technique as an application of FCM for margin assessment in robot-assisted radical prostatectomy (RARP) using the Histolog® scanner. This study describes the accuracy and inter-rater agreement of FCM imaging compared to corresponding paraffin-embedded analysis (PA) among four blinded pathologists for the presence of positive surgical margins (PSM). RARP specimens from patients enrolled in the control arm of the NeuroSAFE PROOF study (NCT03317990) were analysed from April 2022 to February 2023. Prostate specimens were imaged using the Histolog® scanner before formalin fixation and PA. Four trained assessors, blinded to PA, reviewed and analysed FCM images of the posterolateral prostatic surface. A total of 31 prostate specimens were included in the study. PA per lateral side of the prostate identified 11 instances of positive margins. Among the four histopathologists included in our study, FCM achieved a sensitivity of 73-91 and specificity of 94-100% for the presence of PSM. Fleiss' Kappa for inter-rater agreement on PSM was 0.78 (95% confidence interval = 0.64-0.92), indicating substantial agreement. This blinded analysis of FCM versus PA among histopathologists with different experience levels demonstrated high accuracy and substantial inter-rater agreement for diagnosing PSM. This supports the role of the FCM as an alternative to FS.

Multifocal microscopy for functional imaging of neural systems.

Rapid acquisition of large imaging volumes with microscopic resolution is an essential unmet need in biological research, especially for monitoring rapid dynamical processes such as fast activity in distributed neural systems. We present a multifocal strategy for fast, volumetric, diffraction-limited resolution imaging over relatively large and scalable fields of view (FOV) using single-camera exposures. Our multifocal microscopy approach leverages diffraction to image multiple focal depths simultaneously. It is based on a custom-designed diffractive optical element suited to low magnification and large FOV applications and customized prisms for chromatic correction, allowing for wide bandwidth fluorescence imaging. We integrate this system within a conventional microscope and demonstrate that our design can be used flexibly with a variety of magnification/numerical aperture (NA) objectives. We first experimentally and numerically validate this system for large FOV microscope imaging (three orders-of-magnitude larger volumes than previously shown) at resolutions compatible with cellular imaging. We then demonstrate the utility of this approach by visualizing high resolution three-dimensional (3D) distributed neural network at volume rates up to 100Hz. These demonstrations use genetically encoded indicators to measure functional neural imaging both in vitro and in vivo. Finally, we explore its potential in other important applications, including blood flow visualization and real-time, microscopic, volumetric rendering. Our study demonstrates the advantage of diffraction-based multifocal imaging techniques for 3D imaging of mm-scale objects from a single-camera exposure, with important applications in functional neural imaging and other areas benefiting from volumetric imaging.

Microbubble tracking based on partial smoothing-based adaptive generalized labelled Multi-Bernoulli filter for super-resolution imaging

Super-resolution ultrasound (SRUS) can image the vasculature at microscopic resolution according to microbubble (MB) localization, with velocity vector maps obtained based on MB tracking information. High MB concentrations can reduce the acquisition time of SRUS imaging, however adjacent and intersecting vessels are difficult to distinguish, thus decreasing resolution. Low acquisition frame rates affect the precision of flow velocity estimation. This study proposes a partial smoothing-based adaptive generalized labeled multi-Bernoulli filter (SAGLMB) to precisely track the MB motion at different flow velocities. SAGLMB employs a generalized labelled multi-Bernoulli filter (GLMB) for MB trajectory allocation to separate adjacent and intersecting vessels. Furthermore, the nonlinear motion of MB was predicted by an unscented Kalman filter, and a cardinalized probability hypothesis density filter was applied to suppress clutter interference. Finally, the trajectories were smoothed by unscented Rauch-Tung-Striebel to improve the resolution of the SRUS image. The simulation results demonstrate that SAGLMB outperforms the conventional bipartite graph-based tracking at high MB concentrations, achieving at least an 8.55 % improvement in the correctly paired precision, with 3 times increase in the structural similarity index measure. Moreover, SAGLMB can obtain more precise flow velocity estimations with a 4 times improvement than the conventional method. The SRUS results of rabbit kidney show that the proposed method significantly improves resolution of adjacent and intersecting vessels at higher MB concentrations and maintains this performance as the acquisition frame rate decreases. Furthermore, the rat brain microvascular network was reconstructed with 9.21 μm (λ/11.1) resolution. Therefore, SAGLMB can achieve robust SRUS imaging at high concentrations and low acquisition frame rates.

Atomic-level quantitative analysis of electronic functional materials by aberration-corrected STEM

Abstract The stable sub-angstrom resolution of the aberration-corrected scanning transmission electron microscope (AC-STEM) makes it an advanced and practical characterization technique for all materials. Owing to the prosperous advancement in computational technology, specialized software and programs have emerged as potent facilitators across the entirety of electron microscopy characterization process. Utilizing advanced image processing algorithms promotes the rectification of image distortions, concurrently elevating the overall image quality to superior standards. Extracting high-resolution, pixel-level discrete information and converting it into atomic-scale, followed by performing statistical calculations on the physical matters of interest through quantitative analysis, represent an effective strategy to maximize the value of electron microscope images. The efficacious utilization of quantitative analysis of electron microscope images has become a progressively prominent consideration for materials scientists and electron microscopy researchers. This article offers a concise overview of the pivotal procedures in quantitative analysis and summarizes the computational methodologies involved from three perspectives: contrast, lattice and strain, as well as atomic displacements and polarization. It further elaborates on practical applications of these methods in electronic functional materials, notably in piezoelectrics/ferroelectrics and thermoelectrics. It emphasizes the indispensable role of quantitative analysis in fundamental theoretical research, elucidating the structure–property correlations in high-performance systems, and guiding synthesis strategies.

Very high-T hydration in the lower gabbro section of Semail ophiolite, Hydrous components of the lower crust at fast-spreading ridge

Totally fresh black gabbros are observed locally at the very base of the gabbro section in southern Semail ophiolite. Devoid of medium to low-temperature diffuse alteration, the black gabbros are characterized by cloudy plagioclase marked by a high density of hydrothermal inclusions below the optical microscope resolution, evolving into diopside and pargasite crystals ∼10 μm sized. They record hydration at temperature over 900 °C as shown by their major elements composition. Focused Electron Backscattered Electron Diffraction (EBSD) study of the crystalline inclusions, suggests a phase transition from diopside to amphibole, and traces consistent crystallographic relationships of diopside inclusions with their host plagioclase. The detailed geometry of the microcrack system traces a complete fluid path from inter-grain cracking, to plagioclase intra-grain network, possibly thermally-induced. The evidence of solid-state deformation overprinting the magmatic textures suggests that twinning mechanism in plagioclase controls the intra-grain diffusion of hydrous fluids. Located at the interface of the Moho Transition Zone (MTZ) and semi-brittle lithosphere, the ‘black gabbros’ record a narrow domain where focused fluid flow induces rapid cooling below the gabbro solidus at the lowest limit of the magma chamber.

Developing and Benchmarking Sulfate and Sulfamate Force Field Parameters via Ab Initio Molecular Dynamics Simulations To Accurately Model Glycosaminoglycan Electrostatic Interactions.

Glycosaminoglycans (GAGs) are negatively charged polysaccharides found on cell surfaces, where they regulate transport pathways of foreign molecules toward the cell. The structural and functional diversity of GAGs is largely attributed to varied sulfation patterns along the polymer chains, which makes understanding their molecular recognition mechanisms crucial. Molecular dynamics (MD) simulations, thanks to their unmatched microscopic resolution, have the potential to be a reference tool for exploring the patterns responsible for biologically relevant interactions. However, the capability of molecular dynamics force fields used in biosimulations to accurately capture sulfation-specific interactions is not well established, partly due to the intrinsic properties of GAGs that pose challenges for most experimental techniques. In this work, we evaluate the performance of molecular dynamics force fields for sulfated GAGs by studying ion pairing of Ca2+ to sulfated moieties─N-methylsulfamate and methylsulfate─that resemble N- and O-sulfation found in GAGs, respectively. We tested available nonpolarizable (CHARMM36 and GLYCAM06) and explicitly polarizable (Drude and AMOEBA) force fields, and derived new implicitly polarizable models through charge scaling (prosECCo75 and GLYCAM-ECC75) that are consistent with our developed "charge-scaling" framework. The calcium-sulfamate/sulfate interaction free energy profiles obtained with the tested force fields were compared against reference ab initio molecular dynamics (AIMD) simulations, which serve as a robust alternative to experiments. AIMD simulations indicate that the preferential Ca2+ binding mode to sulfated GAG groups is solvent-shared pairing. Only our scaled-charge models agree satisfactorily with the AIMD data, while all other force fields exhibit poorer agreement, sometimes even qualitatively. Surprisingly, even explicitly polarizable force fields display a notable disagreement with the AIMD data, likely attributed to difficulties in their optimization and possible inherent limitations in depicting high-charge-density ion interactions accurately. Finally, the underperforming force fields lead to unrealistic aggregation of sulfated saccharides, which qualitatively disagrees with our understanding of the soft glycocalyx environment. Our results highlight the importance of accurately treating electronic polarization in MD simulations of sulfated GAGs and caution against over-reliance on currently available models without thorough validation and optimization.

Role of Trapped Molecules at Sliding Contacts in Lattice-Resolved Friction.

Understanding atomic friction within a liquid environment is crucial for engineering friction mechanisms and characterizing surfaces. It has been suggested that the lattice resolution of friction force microscope in liquid environments stems from a dry contact state, with all liquid molecules expelled from the area of closest approach between the tip and substrate. Here, we revisit this assertion by performing in-depth friction force microscopy experiments and molecular dynamics simulations of the influence of surrounding water molecules on the dynamic behavior of the nanotribological contact between an amorphous SiO2 probe and a monolayer MoS2 substrate. An analysis of simulation and experimental stick-slip patterns demonstrates the entrapment of water molecules at the contact interface. These trapped water molecules behave as an integral component of the probe and participate in its interaction with the substrate, affecting the dynamics of the probe and preventing long slips. Significantly, surrounding water from the capillary or layer exhibits a replenishing effect, acting as a water reservoir during sliding. This phenomenon facilitates the preservation of lattice-scale resolution across a range of applied normal loads.

Label-Free Single-Cell Cancer Classification from the Spatial Distribution of Adhesion Contact Kinetics.

There is an increasing need for simple-to-use, noninvasive, and rapid tools to identify and separate various cell types or subtypes at the single-cell level with sufficient throughput. Often, the selection of cells based on their direct biological activity would be advantageous. These steps are critical in immune therapy, regenerative medicine, cancer diagnostics, and effective treatment. Today, live cell selection procedures incorporate some kind of biomolecular labeling or other invasive measures, which may impact cellular functionality or cause damage to the cells. In this study, we first introduce a highly accurate single-cell segmentation methodology by combining the high spatial resolution of a phase-contrast microscope with the adhesion kinetic recording capability of a resonant waveguide grating (RWG) biosensor. We present a classification workflow that incorporates the semiautomatic separation and classification of single cells from the measurement data captured by an RWG-based biosensor for adhesion kinetics data and a phase-contrast microscope for highly accurate spatial resolution. The methodology was tested with one healthy and six cancer cell types recorded with two functionalized coatings. The data set contains over 5000 single-cell samples for each surface and over 12,000 samples in total. We compare and evaluate the classification using these two types of surfaces (fibronectin and noncoated) with different segmentation strategies and measurement timespans applied to our classifiers. The overall classification performance reached nearly 95% with the best models showing that our proof-of-concept methodology could be adapted for real-life automatic diagnostics use cases. The label-free measurement technique has no impact on cellular functionality, directly measures cellular activity, and can be easily tuned to a specific application by varying the sensor coating. These features make it suitable for applications requiring further processing of selected cells.

Terahertz control and timing correlations in a transmission electron microscope.

Ultrafast electron microscopy provides a movie-like access to structural dynamics of materials in space and time, but fundamental atomic motions or electron dynamics are, so far, too quick to be resolved. Here, we report the all-optical control, compression, and characterization of electron pulses in a transmission electron microscope by the single optical cycles of laser-generated terahertz light. This concept provides isolated electron pulses and merges the spatial resolution of a transmission electron microscope with the temporal resolution that is offered by a single cycle of laser light. We also report the all-optical control of multi-electron states and find a substantial two-electron and three-electron anticorrelation in the time domain. These results open up the possibility to visualize atomic and electronic motions together with their quantum correlations on fundamental dimensions in space and time.

Tracing the Chromatin: From 3C to Live-Cell Imaging.

Chromatin organization plays a key role in gene regulation throughout the cell cycle. Understanding the dynamics governing the accessibility of chromatin is crucial for insight into mechanisms of gene regulation, DNA replication, and cell division. Extensive research has been done to track chromatin dynamics to explain how cells function and how diseases develop, in the hope of this knowledge leading to future therapeutics utilizing proteins or drugs that modify the accessibility or expression of disease-related genes. Traditional methods for studying the movement of chromatin throughout the cell relied on cross-linking spatially adjacent sections or hybridizing fluorescent probes to chromosomal loci and then constructing dynamic models from the static data collected at different time points. While these traditional methods are fruitful in understanding fundamental aspects of chromatin organization, they are limited by their invasive sample preparation protocols and diffraction-limited microscope resolution. These limitations have been challenged by modern methods based on high- or super-resolution microscopy and specific labeling techniques derived from gene targeting tools. These modern methods are more sensitive and less invasive than traditional methods, therefore allowing researchers to track chromosomal organization, compactness, and even the distance or rate of chromatin domain movement in detail and real time. This review highlights a selection of recently developed methods of chromatin tracking and their applications in fixed and live cells.

Modeling the Depth Resolution of Translucent Layers in Confocal Microscopy

Confocal microscopy is an established technique with manifold applications that offers the capability to perform nondestructive through‐plane imaging. However, depth resolution typically decreases when focusing below the surface of a sample, which limits the applicability. A computational model is introduced that calculates the axial resolution, its decay, and the attenuation coefficient from confocal through‐plane scans of translucent layers. The model is benchmarked with different polymers and objectives (air, water, oil) using a confocal Raman microscope. The algorithm requires a single through‐plane scan that allows to identify the sample by signal intensity differences. It fits the point spread function of the objective at the top and bottom interface of the specimen to extract the resolution at both interfaces and the attenuation coefficient of the sample. It provides robust outputs on various and even multilayered samples if the signal‐to‐noise ratio of the input is sufficient and if the layers are planar and homogeneous. The algorithm of the model is provided open‐source for MATLAB and Python. Quantifying microscope resolution in through‐plane scans can improve image analysis in multiple fields, and this study is a comprehensive proof‐of‐concept for the presented model. It establishes an accessible tool to quantify the depth resolution of confocal microscopy.

Super-resolution Microscopy and Photo-lithography: How can one inspire the other

The principles of microscopy and lithography projection techniques are similar. To improve the resolution of the microscope or further reduce the image projection, both techniques face similar limitations, diffraction limits. The diffraction limit is a limitation of physical optics. In the development process of microscopes, to improve optical microscopy technology, researchers have proposed the idea of reducing the wavelength of light sources and increasing the numerical aperture based on the principle of diffraction limit generation. Modern scientists have proposed techniques to break through the diffraction limit and gradually increase the resolution of microscopes to further improve resolution. These breakthroughs also provide ideas for lithography technology, and researchers have invented techniques such as immersion lithography, multi-exposure, and two-photon direct writing. This article introduces the development process of super-resolution microscopy and lithography technology and analyzes the inspiration and influence of microscopy technology on lithography technology, that is, providing ideas for improving the accuracy of lithography technology.

Label-Free Three-Dimensional Morphological Characterization of Cell Death Using Holographic Tomography.

This study presents a novel label-free approach for characterizing cell death states, eliminating the need for complex molecular labeling that may yield artificial or ambiguous results due to technical limitations in microscope resolution. The proposed holographic tomography technique offers a label-free avenue for capturing precise three-dimensional (3D) refractive index morphologies of cells and directly analyzing cellular parameters like area, height, volume, and nucleus/cytoplasm ratio within the 3D cellular model. We showcase holographic tomography results illustrating various cell death types and elucidate distinctive refractive index correlations with specific cell morphologies complemented by biochemical assays to verify cell death states. These findings hold promise for advancing in situ single cell state identification and diagnosis applications.

#2518 The decrease of the filtration slit density, not proteinuria, is the early indication of the filtration barrier dysfunction

Abstract Background and Aims Intact podocyte foot processes (FP) play a crucial role in ensuring proper selective filtration in the kidney. Changes in FP morphology are thought to be the initial trigger for proteinuria, but definitive proof is still missing. As FP structures are below the optical resolution of light microscopes, changes are investigated by electron microscopy (EM) on ultrathin sections. In this study, the correlation between morphology and proteinuria was investigated using the Podocyte Exact Morphology Measurement Procedure (PEMP), a 3D-SIM-based technique. Our investigation was focused on podocyte damage caused by treatment with nephrotoxic serum (NTS) as a model for focal segmental glomerulosclerosis. Method The mice were treated with nephrotoxic serum (NTS), and kidneys were taken at 24, 48, and 72 hours after injection. Kidney sections (3 µm thick) were prepared for 3D-SIM analysis after staining with podocin and integrin and then fixed in formalin and embedded in paraffin. Filtration slit density (FSD) was quantified using the Podocyte Exact Morphology Measurement Procedure (PEMP) as described earlier (Siegerist et al. 2017). In addition, EM was performed on glutaraldehyde-fixed tissue samples using standard protocols. The albumin to creatinine ratio was also determined. Results We observed that NTS-treated mice developed moderate proteinuria after 48 hours. Using the super-resolution microscopy-based 3D-SIM technique to quantify podocyte PF morphology by calculating the filtrations slit density (FSD) revealed a significant reduction of the FSD in NTS-treated mice already after 24 hours. This structural change was confirmed by transmission electron microscopy analysis, showing that the effacement of podocytes FPs is the first sign of a change in the filtration barrier function before proteinuria is measurable. Conclusion PEMP analysis of standard histological sections from NTS-injected and control mice demonstrated that the first event in the functional loss of the size selectivity of the filtration barrier is the effacement of FP morphology, followed by detectable proteinuria. Therefore, the assessment of the FSD is a promising strategy for early and accurate detection of the loss of filtration barrier integrity, providing opportunities for faster and more precise diagnostics.

DNA choreography: correlating mobility and organization of DNA across different resolutions from loops to chromosomes

The dynamics of DNA in the cell nucleus plays a role in cellular processes and fates but the interplay of DNA mobility with the hierarchical levels of DNA organization is still underexplored. Here, we made use of DNA replication to directly label genomic DNA in an unbiased genome-wide manner. This was followed by live-cell time-lapse microscopy of the labeled DNA combining imaging at different resolutions levels simultaneously and allowing one to trace DNA motion across organization levels within the same cells. Quantification of the labeled DNA segments at different microscopic resolution levels revealed sizes comparable to the ones reported for DNA loops using 3D super-resolution microscopy, topologically associated domains (TAD) using 3D widefield microscopy, and also entire chromosomes. By employing advanced chromatin tracking and image registration, we discovered that DNA exhibited higher mobility at the individual loop level compared to the TAD level and even less at the chromosome level. Additionally, our findings indicate that chromatin movement, regardless of the resolution, slowed down during the S phase of the cell cycle compared to the G1/G2 phases. Furthermore, we found that a fraction of DNA loops and TADs exhibited directed movement with the majority depicting constrained movement. Our data also indicated spatial mobility differences with DNA loops and TADs at the nuclear periphery and the nuclear interior exhibiting lower velocity and radius of gyration than the intermediate locations. On the basis of these insights, we propose that there is a link between DNA mobility and its organizational structure including spatial distribution, which impacts cellular processes.

Scanning Electron Microscopy Imaging of Large DNA Molecules Using a Metal-Free Electro-Stain Composed of DNA-Binding Proteins and Synthetic Polymers.

This paper presents the first scanning electron microscopy (SEM)-based DNA imaging in biological samples. This novel approach incorporates a metal-free electro-stain reagent, formulated by combining DNA-binding proteins and synthetic polymers to enhance the visibility of 2-nm-thick DNA under SEM. Notably, DNA molecules stain with proteins and polymers appear as dark lines under SEM. The resulting DNA images exhibit a thickness of 15.0±4.0nm. As SEM is the primary platform, it integrates seamlessly with various chemically functionalized large surfaces with the aid of microfluidic devices. The approach allows high-resolution imaging of various DNA structures including linear, circular, single-stranded DNA and RNA, originating from nuclear and mitochondrial genomes. Furthermore, quantum dots are successfully visualized as bright labels that are sequence-specifically incorporated into DNA molecules, which highlights the potential for SEM-based optical DNA mapping. In conclusion, DNA imaging using SEM with the novel electro-stain offers electron microscopic resolution with the ease of optical microscopy.

Erbium-based hydrothermal YOF with stark sublevels for in vivo NIR II luminescence nanothermometer

Rare earth luminescent materials have attracted extensive attention in the biomedical field as noncontact temperature monitoring devices with microscopic resolution due to their properties in the visible and near-infrared regions. At the application level, it is required to have a certain temperature monitoring capability in the near-infrared region II window to enhance the tissue penetration depth. Here, two kinds of YOFs: Er[Formula: see text], Yb[Formula: see text] were prepared by co-precipitation and hydrothermal method, and the luminescence was enhanced by ion doping. An Er[Formula: see text]-based ratiometric nanothermometer of 4F[Formula: see text]I[Formula: see text] (672[Formula: see text]nm, upconversion luminescence) to 4I[Formula: see text]I[Formula: see text] (1580[Formula: see text]nm/1566[Formula: see text]nm, NIR II downshifting luminescence) were designed with the Stark energy level. When doped with 2% Zn[Formula: see text], the relative temperature sensitivity of YOF prepared by co-precipitation method was improved from 0.30% [Formula: see text] (30∘C) to 0.59% [Formula: see text] (30∘C), expanding its use as a temperature monitoring device possibility. The temperature sensitivity of YOF prepared by hydrothermal method was 1.01% [Formula: see text] (30∘C). Finally, the NIR II luminescence of the prepared nanothermometer was used as a control for temperature monitoring of heating sites in mice. The results showed that it can distinguish heating site from control site and no significant cytotoxicity or damage to the tissues was revealed, indicating its broad prospects in the biomedical field and other temperature monitoring scenarios in the future.

Monolithic deformable mirror based on lithium niobate single crystal for high-resolution X-ray adaptive microscopy

X-ray microscopy is very promising not only for nondestructive and high-spatial-resolution observation of the internal structure of a sample but also for elemental distribution and chemical state analysis. However, the spatial resolution of microscopes remains unsatisfactory owing to the fabrication error in the objective lens. To realize an ultra-high-resolution, we propose and develop a monolithic deformable mirror based on a lithium niobite single crystal and a novel adaptive imaging system based on it. An X-ray interferometer confirmed that shape modification is possible with an accuracy of 0.67 nm in peak to valley under high stability (0.17 nm over 7 h) and hysteresis-free deformation control. Introducing this adaptive mirror into an X-ray microscope based on advanced Kirkpatrick-Baez mirror optics and correcting the wavefront aberration demonstrated that the X-ray image quality could be significantly improved.