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Accelerated FRET-PAINT microscopy
摘要： Recent development of FRET-PAINT microscopy significantly improved the imaging speed of DNA-PAINT, the previously reported super-resolution fluorescence microscopy with no photobleaching problem. Here we try to achieve the ultimate speed limit of FRET-PAINT by optimizing the camera speed, dissociation rate of DNA probes, and bleed-through of the donor signal to the acceptor channel, and further increase the imaging speed of FRET-PAINT by 8-fold. Super-resolution imaging of COS-7 microtubules shows that high-quality 40-nm resolution images can be obtained in just tens of seconds.
关键词： FRET-PAINT,Super-resolution fluorescence microscopy,FRET,Single-molecule localization microscopy
更新于2025-09-23 15:22:29
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A miniaturized, tethered, spectrally-encoded confocal endomicroscopy capsule
摘要： The tethered spectrally-encoded confocal endomicroscopy (SECM) capsule is an imaging device that once swallowed by an unsedated patient can visualize cellular morphologic changes associated with gastrointestinal (GI) tract diseases in vivo. Recently, we demonstrated a tethered SECM capsule for counting esophageal eosinophils in patients with eosinophilic esophagitis (EoE) in vivo. Yet, the current tethered SECM capsule is far too long to be widely utilized for imaging pediatric patients, who constitute a major portion of the EoE patient population. In this paper, we present a new tethered SECM capsule that is 33% shorter, has an easier and repeatable fabrication process, and produces images with reduced speckle noise.
关键词： spectrally encoded confocal microscopy,confocal endomicroscopy,eosinophilic esophagitis,reflectance confocal microscopy,esophageal imaging,tethered capsule endomicroscopy
更新于2025-09-23 15:22:29
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Optical Band Gap, Local Work Function and Field Emission Properties of MBE Grown β-MoO3 Nanoribbons
摘要： Monoclinic molybdenum trioxide (β-MoO3) nanostructures (shaped like nanoribbons: NRs) were grown on Si(100), Si(5512) and fluorine-doped tin oxide (FTO) by molecular beam epitaxy (MBE) technique under ultra-high vacuum (UHV) conditions. The dependence of substrate conditions and the effective thickness of MoO3 films on the morphology of nanostructures and their structural aspects were reported. The electron microscopy measurements show that the length and the aspect ratio of nanostructures increased by, 260% without any significant change in the width for a change in effective thickness from 5 nm to 30 nm. NRs are grown along <011> for all the effective thickness of MoO3 films. Similarly, when we increased the film thickness from 5 nm to 30 nm, the optical band gap decreased from 3.38± 0.01eV to 3.17± 0.01eV and the local work function increased from 5.397 ± 0.025 eV to 5.757 ± 0.030 eV. Field emission turn-on field decreased from 3.58 V/μm for 10-μA/cm2 to 2.5 V/μm and field enhancement factor increased from 1.1×104 to 5.9×104 for effective thickness variation of 5 nm to 30 nm β-MoO3 structures. The β-MoO3 nanostructures found to be much better than the α-MoO3 nanostructures due to low work function, low turn on field and high field enhancement factor, and are expected to be useful applications.
关键词： β-MoO3 nanostructures,Field emission and Kelvin probe force microscopy (KPFM),Optical band gap,Molecular beam epitaxy (MBE),Electron microscopy
更新于2025-09-23 15:22:29
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Correlative infrared nanospectroscopy and transmission electron microscopy to investigate nanometric amyloid fibrils: prospects and challenges
摘要： Propagation of structural information through conformational changes in host-encoded amyloid proteins is at the root of many neurodegenerative disorders. Although important breakthroughs have been made in the field, fundamental issues like the 3D-structures of the fibrils involved in some of those disorders are still to be elucidated. To better characterise those nanometric fibrils, a broad range of techniques is currently available. Nevertheless none of them is able to perform direct chemical characterisation of single protein fibrils. In this work, we propose to investigate the structure of the C-terminal region of a bacterial protein called Hfq as a model amyloidogenic protein, using a correlative approach. The complementary techniques used are transmission electron microscopy and a newly developed infrared nanospectroscopy technique called AFM-IR. We introduce and discuss the strategy that we have implemented as well as the protocol, challenges and difficulties encountered during this study to characterise amyloid assemblies at the nearly single-molecule level.
关键词： correlative measurements,transmission electron microscopy,infrared nanospectroscopy,fibrils,Hfq,atomic force microscopy,Amyloid
更新于2025-09-23 15:22:29
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Investigation of Disorder in Mixed Phase, <i>sp</i> <sup>2</sup> – <i>sp</i> <sup>3</sup> Bonded Graphene-Like Nanocarbon
摘要： Disorder in a mixed phase, sp2–sp3 bonded graphene-like nanocarbon (GNC) lattice has been extensively studied for its electronic and field emission properties. Morphological investigations are performed using scanning electron microscopy (SEM) which depicts microstructures comprising of atomically flat terraces (c-planes) with an abundance of edges (ab planes which are orthogonal to c-planes). Scanning tunneling microscopy (STM) is used to observe the atomic structure of basal planes whereas field emission microscopy (FEM) is found to be suitable for resolving nano-topography of edges. STM images revealed the hexagonal and non-hexagonal atomic arrangements in addition to a variety of defect structures. Scanning tunneling spectroscopy is carried out to study the effect of this short-range disorder on the local density of states. Current versus voltage (I–V) characteristics have been recorded at different defect sites and are compared with respect to the extent of the defect. As sharp edges of GNC are expected to be excellent field emitters, because of low work function and high electric field, enhancement in current is observed particularly when applied electric field is along basal planes. Therefore, it is worthwhile to investigate field emission from these samples. The FEM images show a cluster of bright spots at low voltages which later transformed into an array resembling ledges of ab-planes with increasing voltage. Reproducible I–V curves yield linear Fowler-Nordheim plots supporting field emission as the dominant mechanism of electron emission. Turn on field for 10 μA current is estimated to be ～3 V/μm.
关键词： Field Emission Microscopy,Graphene-Like Nanocarbon,Scanning Tunneling Spectroscopy,Scanning Tunneling Microscopy
更新于2025-09-23 15:22:29
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Investigation of CVD graphene as-grown on Cu foil using simultaneous scanning tunneling/atomic force microscopy
摘要： Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) images of graphene reveal either a triangular or honeycomb pattern at the atomic scale depending on the imaging parameters. The triangular patterns at the atomic scale are particularly difficult to interpret, as the maxima in the images could be every other carbon atom in the six-fold hexagonal array or even a hollow site. Carbon sites exhibit an inequivalent electronic structure in HOPG or multilayer graphene due to the presence of a carbon atom or a hollow site underneath. In this work, we report small-amplitude, simultaneous STM/AFM imaging using a metallic (tungsten) tip, of the graphene surface as-grown by chemical vapor deposition (CVD) on Cu foils. Truly simultaneous operation is possible only with the use of small oscillation amplitudes. Under a typical STM imaging regime the force interaction is found to be repulsive. Force–distance spectroscopy revealed a maximum attractive force of about 7 nN between the tip and carbon/hollow sites. We obtained different contrast between force and STM topography images for atomic features. A honeycomb pattern showing all six carbon atoms is revealed in AFM images. In one contrast type, simultaneously acquired STM topography revealed hollow sites to be brighter. In another, a triangular array with maxima located in between the two carbon atoms was acquired in STM topography.
关键词： scanning tunneling microscopy,CVD graphene,simultaneous operation,atomic force microscopy,small amplitude
更新于2025-09-23 15:22:29
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In Situ Quantification of the Young’s Modulus of Nuclei In Multiple Cellular States Using A Modified Fiber Probe Sensor
摘要： In this work, a modified fiber probe sensor (MFP sensor) with a considerable length-diameter ratio tip was developed to quantitatively characterize the Young’s modulus of the cell nucleus in multiple cellular states. The MFP sensor has a needle tip with an extended length of 30 μm and a diameter of 150 nm. The length of the tip exceeds the diameter of most cells, so that it can penetrate the cell membrane with minimal damage and reach the nucleus. This allows the measurement of the Young’s modulus of intact cell nuclei under different cellular states without the phenomenon that the cantilever contacts the cell membrane. Moreover, the stiffness of the MFP sensor is reduced by a factor of 25 to better match that of the cell membrane and nucleus, which enables high-precision mechanical measurements. The MFP sensor was successfully used to quantify the Young’s modulus of the intact cell nuclei in the non-adherent, adherent and early apoptotic states. Experimental results validated the capability and versatility of the developed method.
关键词： In Situ,Modified Fiber Probe Sensor,Young’s Modulus,Cell Nucleus,Atomic Force Microscopy
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - Rome, Italy (2018.6.11-2018.6.13)] 2018 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - Extracting Features from Optical Coherence Tomography for Measuring Optical Nerve Thickness
摘要： Neurological pathologies, especially optical neuropathologies, can be studied by means of OCT (optical coherence tomography). Tomography generally allows to investigate inner structures of a tissue such as mass, and profiles of liquid flow. OCT is intended as an interferometry-based imaging technique that provides cross-sectional views of substrates. It allows to measure micro-scale cross-sectional imaging of biological tissue. While ultrasound uses sound waves, it acts like it but with a low coherence light. Optical nerve thickness has an impact on different neurological pathologies, and in particular as an indicator of epilepsy. We propose a dedicated technique for measuring optical nerve thickness and identifying its quality by means of processing front eye image in nanoscale. Experimental measurements have been performed, and a database of 10 teenagers has been used for that.
关键词： Micro and Nanotechnology,Optical nerve thickness measurement,Optical coherence Tomography,Neuro-disorders,Epilepsy,Atomic Force Microscopy,EEG
更新于2025-09-23 15:22:29
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[Methods in Molecular Biology] T-Cell Motility Volume 1930 (Methods and Protocols) || Live Imaging of Resident T-Cell Migration in Human Lymphoid Tissue Slices Using Confocal Microscopy
摘要： In order to mount a potent immune response, immune cells must move actively through tissues. As an example, T-cell need to migrate within lymph nodes in order to scan the surface of many dendritic cells and recognize rare expressed antigens. The recent development of improved imaging approaches, such as two-photon microscopy, and the use of powerful mouse models have shed light on some of the mechanisms that regulate the migration of immune cells in many organs. Whereas such systems have provided valuable insights, they do not always predict human responses. In human, our knowledge in the field mainly comes from a description of fixed tissue samples. However, these studies lack a temporal dimension since samples have been fixed. In order to overcome some of these limitations, we describe, in this methodology chapter, an experimental system of fresh human adenoid slices to monitor the dynamics of resident T-lymphocytes that have been stained with directly-coupled fluorescent antibodies. Combined with confocal fluorescent imaging, this preparation offers an effective approach to imaging immune cells in a three-dimensional (3D) human lymphoid tissue environment.
关键词： Immunostaining,Confocal microscopy,Motility,Vibratome,T-cells
更新于2025-09-23 15:22:29
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[Methods in Molecular Biology] T-Cell Motility Volume 1930 (Methods and Protocols) || Three-Dimensional Structured Illumination Microscopy (3D-SIM) to Dissect Signaling Cross-Talks in Motile T-Cells
摘要： Visualization of signal transduction events in T-cells has always been a challenge due to their miniscule size. Recent advancement in super-resolution microscopy techniques presents many new opportunities to navigate the spatial and temporal signaling cross-talks in motile T-cells. Here, we provide technical details, optimal conditions, and critical practical considerations that need to be taken into account during cell handling, sample preparation, and image acquisition of motile T-cells for performing three-dimensional structured illumination microscopy (3D-SIM).
关键词： 3D-SIM,Immunostaining,Super-resolution microscopy
更新于2025-09-23 15:22:29