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Xuanze Chen, Rongqin Li, Zhihe Liu, Kai Sun, Zezhou Sun, Danni Chen, Gaixia Xu, Peng Xi, Changfeng Wu, Yujie Sun
Two types of small photoblinking Pdots with high brightness, strong photostability, and favorable biocompatibility, are designed. Super-resolution optical fluctuation imaging is achieved using these Pdots. Imaging of subcellular structures demonstrates that these small photoblinking Pdots are outstanding probes for fast, long-term super-resolution fluorescence imaging.
November 24, 2016: Advanced Materials
Emiliano Cortés, Paloma Arroyo Huidobro, Hugo G Sinclair, Stina Guldbrand, William J Peveler, Timothy Davies, Simona Parrinello, Frederik Görlitz, Chris Dunsby, Mark A A Neil, Yonatan Sivan, Ivan P Parkin, Paul M W French, Stefan A Maier
Plasmonic nanoparticles influence the absorption and emission processes of nearby emitters due to local enhancements of the illuminating radiation and the photonic density of states. Here, we use the plasmon resonance of metal nanoparticles in order to enhance the stimulated depletion of excited molecules for super-resolved nanoscopy. We demonstrate stimulated emission depletion (STED) nanoscopy with gold nanorods with a long axis of only 26 nm and a width of 8 nm that provide an enhancement of up to 50% of the resolution compared to fluorescent-only probes without plasmonic components irradiated with the same depletion power...
October 30, 2016: ACS Nano
Jie Xiao, Yves F Dufrêne
Microbial cells have developed sophisticated multicomponent structures and machineries to govern basic cellular processes, such as chromosome segregation, gene expression, cell division, mechanosensing, cell adhesion and biofilm formation. Because of the small cell sizes, subcellular structures have long been difficult to visualize using diffraction-limited light microscopy. During the last three decades, optical and force nanoscopy techniques have been developed to probe intracellular and extracellular structures with unprecedented resolutions, enabling researchers to study their organization, dynamics and interactions in individual cells, at the single-molecule level, from the inside out, and all the way up to cell-cell interactions in microbial communities...
October 26, 2016: Nature Microbiology
Pablo Alonso-González, Alexey Y Nikitin, Yuanda Gao, Achim Woessner, Mark B Lundeberg, Alessandro Principi, Nicolò Forcellini, Wenjing Yan, Saül Vélez, Andreas J Huber, Kenji Watanabe, Takashi Taniguchi, Félix Casanova, Luis E Hueso, Marco Polini, James Hone, Frank H L Koppens, Rainer Hillenbrand
Terahertz (THz) fields are widely used for sensing, communication and quality control. In future applications, they could be efficiently confined, enhanced and manipulated well below the classical diffraction limit through the excitation of graphene plasmons (GPs). These possibilities emerge from the strongly reduced GP wavelength, λp, compared with the photon wavelength, λ0, which can be controlled by modulating the carrier density of graphene via electrical gating. Recently, GPs in a graphene/insulator/metal configuration have been predicted to exhibit a linear dispersion (thus called acoustic plasmons) and a further reduced wavelength, implying an improved field confinement, analogous to plasmons in two-dimensional electron gases (2DEGs) near conductive substrates...
October 24, 2016: Nature Nanotechnology
Karin Nienhaus, Gerd Ulrich Nienhaus
Photoactivatable fluorescent proteins (FPs) have become essential markers for nanoscopy on live specimens. In this issue of ACS Nano, Wang et al. present a reversibly photoswitching FP, GMars-Q, which they promote as an advanced marker for RESOLFT imaging because of its low residual intensity in the off state and low switching fatigue. Here, we explain the observed peculiar photobleaching behavior of GMars-Q by a mechanism that involves efficient shelving of proteins in dark states, resulting in low switching fatigue and low residual off intensity...
October 10, 2016: ACS Nano
Marjolein B M Meddens, Elvis Pandzic, Johan A Slotman, Dominique Guillet, Ben Joosten, Svenja Mennens, Laurent M Paardekooper, Adriaan B Houtsmuller, Koen van den Dries, Paul W Wiseman, Alessandra Cambi
Podosomes are cytoskeletal structures crucial for cell protrusion and matrix remodelling in osteoclasts, activated endothelial cells, macrophages and dendritic cells. In these cells, hundreds of podosomes are spatially organized in diversely shaped clusters. Although we and others established individual podosomes as micron-sized mechanosensing protrusive units, the exact scope and spatiotemporal organization of podosome clustering remain elusive. By integrating a newly developed extension of Spatiotemporal Image Correlation Spectroscopy with novel image analysis, we demonstrate that F-actin, vinculin and talin exhibit directional and correlated flow patterns throughout podosome clusters...
October 10, 2016: Nature Communications
Patrick Maurer, J Ignacio Cirac, Oriol Romero-Isart
We show that ultrashort pulses can be focused, in a particular instant, to a spot size given by the wavelength associated with its spectral width. For attosecond pulses this spot size is within the nanometer scale. Then we show that a two-level system can be left excited after interacting with an ultrashort pulse whose spectral width is larger than the transition frequency, and that the excitation probability depends not on the field amplitude but on the field intensity. The latter makes the excitation profile have the same spot size as the ultrashort pulse...
September 2, 2016: Physical Review Letters
Jinxing Li, Wenjuan Liu, Tianlong Li, Isaac Rozen, Jason Zhao, Babak Bahari, Boubacar Kante, Joseph Wang
Optical imaging plays a fundamental role in science and technology but is limited by the ability of lenses to resolve small features below the fundamental diffraction limit. A variety of nanophotonic devices, such as metamaterial superlenses and hyperlenses, as well as microsphere lenses, have been proposed recently for subdiffraction imaging. The implementation of these micro/nanostructured lenses as practical and efficient imaging approaches requires locomotive capabilities to probe specific sites and scan large areas...
October 12, 2016: Nano Letters
Nirod Kumar Sarangi, Ilanila I P, K G Ayappa, Sandhya S Visweswariah, Jaydeep Kumar Basu
Membrane-protein interactions play a central role in membrane mediated cellular processes ranging from signaling, budding, and fusion, to transport across the cell membrane. Of particular significance is the process of efficient protein olgomerization and transmembrane pore formation on the membrane surface; the primary virulent pathway for the action of antimicrobial peptides and pore forming toxins (PFTs). The suggested nanoscopic length scales and dynamic nature of such membrane lipid-protein interactions makes their detection extremely challenging...
September 20, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Carmine Di Rienzo, Enrico Gratton, Fabio Beltram, Francesco Cardarelli
The enormous wealth of information available today from optical microscopy measurements on living samples is often underexploited. We argue that spatiotemporal analysis of fluorescence fluctuations using multiple detection channels can enhance the performance of current nanoscopy methods and provide further insight into dynamic molecular processes of high biological relevance.
August 23, 2016: Biophysical Journal
Sheng Wang, Xuanze Chen, Lei Chang, Ruiying Xue, Haifeng Duan, Yujie Sun
The recent development of reversibly switchable fluorescent proteins (RSFPs) has promoted reversible saturable optical fluorescence transitions (RESOLFT) nanoscopy as a general scheme for live cell super-resolution imaging. However, continuous, long-term live cell RESOLFT nanoscopy is still hindered mainly because of the unsatisfactory properties of existing RSFPs. In this work, we report GMars-Q, a monomeric RSFP with low residual off-state fluorescence and strong fatigue resistance attributed to a biphasic photobleaching process...
August 19, 2016: ACS Nano
Urška Slapšak, Giulia Salzano, Ladan Amin, Romany N N Abskharon, Gregor Ilc, Blaž Zupančič, Ivana Biljan, Janez Plavec, Gabriele Giachin, Giuseppe Legname
The cellular form of the prion protein (PrP(C)) is a highly conserved glycoprotein mostly expressed in the central and peripheral nervous systems by different cell types in mammals. A misfolded, pathogenic isoform, denoted as prion, is related to a class of neurodegenerative diseases known as transmissible spongiform encephalopathy. PrP(C) function has not been unequivocally clarified, and it is rather defined as a pleiotropic protein likely acting as a dynamic cell surface scaffolding protein for the assembly of different signaling modules...
October 14, 2016: Journal of Biological Chemistry
Yohannes Abate, Daniel Seidlitz, Alireza Fali, Sampath Gamage, Viktoriia Babicheva, Vladislav S Yakovlev, Mark I Stockman, Ramon Collazo, Dorian Alden, Nikolaus Dietz
Phase separations in ternary/multinary semiconductor alloys is a major challenge that limits optical and electronic internal device efficiency. We have found ubiquitous local phase separation in In1-xGaxN alloys that persists to nanoscale spatial extent by employing high-resolution nanoimaging technique. We lithographically patterned InN/sapphire substrates with nanolayers of In1-xGaxN down to few atomic layers thick that enabled us to calibrate the near-field infrared response of the semiconductor nanolayers as a function of composition and thickness...
September 7, 2016: ACS Applied Materials & Interfaces
James N Monks, Bing Yan, Nicholas Hawkins, Fritz Vollrath, Zengbo Wang
It was recently discovered that transparent microspheres and cylinders can function as a super-resolution lens (i.e., superlens) to focus light beyond the diffraction limit. A number of high-resolution applications based on these lenses have been successfully demonstrated and span nanoscopy, imaging, and spectroscopy. Fabrication of these superlenses, however, is often complex and requires sophisticated engineering processes. Clearly an easier model candidate, such as a naturally occurring superlens, is highly desirable...
September 14, 2016: Nano Letters
Janina Hanne, Fabian Göttfert, Jiří Schimer, Maria Anders-Össwein, Jan Konvalinka, Johann Engelhardt, Barbara Müller, Stefan W Hell, Hans-Georg Kräusslich
Concomitant with human immunodeficiency virus type 1 (HIV-1) budding from a host cell, cleavage of the structural Gag polyproteins by the viral protease (PR) triggers complete remodeling of virion architecture. This maturation process is essential for virus infectivity. Electron tomography provided structures of immature and mature HIV-1 with a diameter of 120-140 nm, but information about the sequence and dynamics of structural rearrangements is lacking. Here, we employed super-resolution STED (stimulated emission depletion) fluorescence nanoscopy of HIV-1 carrying labeled Gag to visualize the virion architecture...
September 27, 2016: ACS Nano
Nils Gustafsson, Siân Culley, George Ashdown, Dylan M Owen, Pedro Matos Pereira, Ricardo Henriques
Despite significant progress, high-speed live-cell super-resolution studies remain limited to specialized optical setups, generally requiring intense phototoxic illumination. Here, we describe a new analytical approach, super-resolution radial fluctuations (SRRF), provided as a fast graphics processing unit-enabled ImageJ plugin. In the most challenging data sets for super-resolution, such as those obtained in low-illumination live-cell imaging with GFP, we show that SRRF is generally capable of achieving resolutions better than 150 nm...
August 12, 2016: Nature Communications
Mohendra Roy, Dongmin Seo, Sangwoo Oh, Ji-Woon Yang, Sungkyu Seo
Recently, lens-free imaging has evolved as an alternative imaging technology. The key advantages of this technology, including simplicity, compactness, low cost, and flexibility of integration with other components, have facilitated the realization of many innovative applications, especially, in the fields of the on-chip lens-free imaging and sensing. In this review, we discuss the development of lens-free imaging, from theory to applications. This article includes the working principle of lens-free digital inline holography (DIH) with coherent and semi coherent light, on-chip lens-free fluorescence imaging and sensing, lens-free on-chip tomography, lens-free on-chip gigapixel nanoscopy, detection of nanoparticles using on-chip microscopy, wide field microscopy, and lens-free shadow image based point-of-care systems...
August 1, 2016: Biosensors & Bioelectronics
Jacopo Antonello, Emil B Kromann, Daniel Burke, Joerg Bewersdorf, Martin J Booth
Stimulated emission depletion (STED) microscopes, like all super-resolution methods, are sensitive to aberrations. Of particular importance are aberrations that affect the quality of the depletion focus, which requires a point of near-zero intensity surrounded by strong illumination. We present analysis, modeling, and experimental measurements that show the effects of coma aberrations on depletion patterns of two-dimensional (2D) and three-dimensional (3D) STED configurations. Specifically, we find that identical coma aberrations create focal shifts in opposite directions in 2D and 3D STED...
August 1, 2016: Optics Letters
Tao Liu, Shuming Yang, Zhuangde Jiang
Planar multi-annular nanostructured metasurfaces have provided a new way to realize far-field optical super-resolution focusing and nanoscopic imaging, due to the delicate interference of propagating waves diffracted from the metasurface mask. However, so far there are no proper methods that can be used to essentially interpret the super-focusing and nano-imaging mechanisms. This research proposes an electromagnetic methodology for the super-resolution investigation of nanostructured metasurfaces. We have physically modeled the polarization-dependent transmission effect of the subwavelength nanostructure and the vectorial imaging process of a high-numerical-aperture microscopic system...
July 25, 2016: Optics Express
Yurui Fang, Ruggero Verre, Lei Shao, Peter Nordlander, Mikael Käll
Three-dimensional chiral plasmonic nanostructures have been shown to be able to dramatically boost photon-spin selective light-matter interactions, potentially leading to novel photonics, molecular spectroscopy, and light-harvesting applications based on circularly polarized light. Here, we show that chiral split-ring gold nanoresonators interfaced to a wide band gap semiconductor exhibit a contrast in hot-electron transfer rate between left-handed and right-handed visible light that essentially mimics the far-field circular dichroism of the structures...
August 10, 2016: Nano Letters
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