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Two photon microscopy

Hyemin Kim, Won Ho Kong, Keum-Yong Seong, Dong Kyung Sung, Hyeonseon Jeong, Jin Kon Kim, Seung Yun Yang, Sei Kwang Hahn
Epidermal growth factor (EGF) has been recognized as an excellent wound healing agent due to its therapeutic function stimulating skin cell growth, proliferation and differentiation. However, the transdermal delivery of EGF poses a significant challenge due to its short half-life and lack of efficient formulation. Here, to improve the transdermal delivery efficiency, EGF was conjugated to hyaluronate (HA), which was formulated into a patch-type film for skin wound healing. HA-EGF conjugate was synthesized by coupling reaction between aldehyde-modified HA and N-terminal amine group of EGF to minimize the loss of biological activities...
October 24, 2016: Biomacromolecules
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
Sava Sakadžić, Mohammad A Yaseen, Rajeshwer Jaswal, Emmanuel Roussakis, Anders M Dale, Richard B Buxton, Sergei A Vinogradov, David A Boas, Anna Devor
The cerebral metabolic rate of oxygen ([Formula: see text]) is an essential parameter for evaluating brain function and pathophysiology. However, the currently available approaches for quantifying [Formula: see text] rely on complex multimodal imaging and mathematical modeling. Here, we introduce a method that allows estimation of [Formula: see text] based on a single measurement modality-two-photon imaging of the partial pressure of oxygen ([Formula: see text]) in cortical tissue. We employed two-photon phosphorescence lifetime microscopy (2PLM) and the oxygen-sensitive nanoprobe PtP-C343 to map the tissue [Formula: see text] distribution around cortical penetrating arterioles...
October 2016: Neurophotonics
Vincenzo Amendola, Stefano Scaramuzza, Francesco Carraro, Elti Cattaruzza
Laser ablation in liquids (LAL) emerged as a powerful technique for the synthesis of multielement nanoparticles (NPs) such as metal alloys with thermodynamically forbidden composition. Consequently, there is a great interest in expanding the current knowledge about NPs formation during LAL, in order to improve the control on product structure and to extend the range of compositions accessible by this technique. Here we performed a systematic investigation on alloy NPs formation by nanosecond LAL of Au/Fe/glass multilayers with different thickness and order of deposition...
October 13, 2016: Journal of Colloid and Interface Science
Claure N Lunardi, Anderson J Gomes, Sandeep Palepu, P Thilanka Galwaduge, Elizabeth M C Hillman
Here we present the production, characterization and in-vivo assessment of cresyl violet-loaded biodegradable PLGA nano/microparticles (CV-NP and CV-MP). We demonstrate that the beneficial spectral characteristics of cresyl violet make it suitable as a tracer for particle-based drug delivery using both hyperspectral wide field and two-photon excited fluorescence microscopy. Particles were prepared using a cosolvent method, after which the physicochemical properties such as morphology, particle size, drug entrapment efficiency, drug loading and in vitro drug release behavior were measured in addition to spectroscopic properties, such as absorption, fluorescence and infrared spectra...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Daniel Jaeger, Christian Pilger, Henning Hachmeister, Elina Oberländer, Robin Wördenweber, Julian Wichmann, Jan H Mussgnug, Thomas Huser, Olaf Kruse
Oleaginous photosynthetic microalgae hold great promise as non-food feedstocks for the sustainable production of bio-commodities. The algal lipid quality can be analysed by Raman micro-spectroscopy, and the lipid content can be imaged in vivo in a label-free and non-destructive manner by coherent anti-Stokes Raman scattering (CARS) microscopy. In this study, both techniques were applied to the oleaginous microalga Monoraphidium neglectum, a biotechnologically promising microalga resistant to commonly applied lipid staining techniques...
October 21, 2016: Scientific Reports
Markus Seeger, Angelos Karlas, Dominik Soliman, Jaroslav Pelisek, Vasilis Ntziachristos
Carotid artery atherosclerosis is a main cause of stroke. Understanding atherosclerosis biology is critical in the development of targeted prevention and treatment strategies. Consequently, there is demand for advanced tools investigating atheroma pathology. We consider hybrid optoacoustic and multiphoton microscopy for the integrated and complementary interrogation of plaque tissue constituents and their mutual interactions. Herein, we visualize human carotid plaque using a hybrid multimodal imaging system that combines optical resolution optoacoustic (photoacoustic) microscopy, second and third harmonic generation microscopy, and two-photon excitation fluorescence microscopy...
September 2016: Photoacoustics
K M Naga Srinivas Nadella, Hana Roš, Chiara Baragli, Victoria A Griffiths, George Konstantinou, Theo Koimtzis, Geoffrey J Evans, Paul A Kirkby, R Angus Silver
Understanding how neural circuits process information requires rapid measurements of activity from identified neurons distributed in 3D space. Here we describe an acousto-optic lens two-photon microscope that performs high-speed focusing and line scanning within a volume spanning hundreds of micrometers. We demonstrate its random-access functionality by selectively imaging cerebellar interneurons sparsely distributed in 3D space and by simultaneously recording from the soma, proximal and distal dendrites of neocortical pyramidal cells in awake behaving mice...
October 17, 2016: Nature Methods
Raf Donders, Kathleen Sanen, Rik Paesen, Eli Slenders, Wilfried Gyselaers, Piet Stinissen, Marcel Ameloot, Niels Hellings
In situ detection of MSCs remains difficult and warrants additional methods to aid with their characterization in vivo. Two-photon confocal laser scanning microscopy (TPM) and second harmonic generation (SHG) could fill this gap. Both techniques enable the detection of cells and extracellular structures, based on intrinsic properties of the specific tissue and intracellular molecules under optical irradiation. TPM imaging and SHG imaging have been used for label-free monitoring of stem cells differentiation, assessment of their behavior in biocompatible scaffolds, and even cell tracking in vivo...
2016: Stem Cells International
Shoriya Aruni Abdul Manaf, Gurumurthy Hedge, Uttam Kumar Mandal, Wong Tin Wui, Partha Roy
BACKGROUND: Nano-scale carbon systems are emerging alternatives in drug delivery and bioimaging applications of which they gradually replace the quantum dots characterized by toxic heavy metal content in the latter application. OBJECTIVE: The work intended to use carbon nanospheres synthesized from biowaste Sago bark for cancer cell imaging applications. METHODS: This study synthesised carbon nanospheres from biowaste Sago bark using a catalyst-free pyrolysis technique...
October 17, 2016: Current Drug Delivery
Jitao Zhang, Antonio Fiore, Seok-Hyun Yun, Hanyoup Kim, Giuliano Scarcelli
Brillouin spectroscopy probes the mechanical properties of material by measuring the optical frequency shift induced by photon-phonon scattering interactions. In traditional configurations, Brillouin spectrometers measure only one point of the sample at a time. This results in long acquisition times for mechanical imaging of large areas. In this work, we demonstrate a parallel detection configuration where the Brillouin shift of hundreds of points in a line can be measured simultaneously. In mm-sized samples, this novel configuration effectively shortens the acquisition time of two-dimensional Brillouin imaging from hours to tens of seconds, thus making it a powerful technology for label-free mechanical characterization of tissue and biomaterials...
October 14, 2016: Scientific Reports
Jung Eun Park, Xian Feng Zhang, Sang-Ho Choi, Junko Okahara, Erika Sasaki, Afonso C Silva
Chronic monitoring of neuronal activity in the living brain with optical imaging techniques became feasible owing to the continued development of genetically encoded calcium indicators (GECIs). Here we report for the first time the successful generation of transgenic marmosets (Callithrix jacchus), an important nonhuman primate model in neurophysiological research, which were engineered to express the green fluorescent protein (GFP)-based family of GECIs, GCaMP, under control of either the CMV or the hSyn promoter...
October 11, 2016: Scientific Reports
Tom T A Lummen, Raymond J Lamb, Gabriele Berruto, Thomas LaGrange, Luca Dal Negro, F Javier García de Abajo, Damien McGrouther, B Barwick, F Carbone
Capturing and controlling plasmons at buried interfaces with nanometre and femtosecond resolution has yet to be achieved and is critical for next generation plasmonic devices. Here we use light to excite plasmonic interference patterns at a buried metal-dielectric interface in a nanostructured thin film. Plasmons are launched from a photoexcited array of nanocavities and their propagation is followed via photon-induced near-field electron microscopy (PINEM). The resulting movie directly captures the plasmon dynamics, allowing quantification of their group velocity at ∼0...
October 11, 2016: Nature Communications
Gary Razinskas, Deirdre Kilbane, Pascal Melchior, Peter Geisler, Enno Krauss, Stefan Mathias, Bert Hecht, Martin Aeschlimann
The design of noble-metal plasmonic devices and nanocircuitry requires a fundamental understanding and control of the interference of plasmonic modes. Here we report the first visualization of the propagation and interference of guided modes in a showcase plasmonic nanocircuit using normal-incidence nonlinear two-photon photoemission electron microscopy (PEEM). We demonstrate that in contrast to the commonly used grazing-incidence illumination scheme, normal-incidence PEEM provides a direct image of the structure's near-field intensity distribution due to the absence of beating patterns and despite the transverse character of the plasmonic modes...
October 10, 2016: Nano Letters
Georgios K Eleftheriadis, Maria Filippousi, Vassiliki Tsachouridou, Maria-Anna Darda, Lamprini Sygellou, Ioanna Kontopoulou, Nikolaos Bouropoulos, Theodore Steriotis, Georgia Charalambopoulou, Ioannis S Vizirianakis, Gustaaf Van Tendeloo, Dimitrios G Fatouros
Towards the development of novel drug carriers for oral delivery of poorly soluble drugs mesoporous aerogel carbons (CAs), namely CA10 and CA20 with different pore sizes (10 and 20nm, respectively), were evaluated. The non-steroidal anti-inflammatory lipophilic compound ibuprofen was incorporated via passive loading. The drug loaded carbon aerogels were systemically investigated by means of High-Resolution Transmission Electron Microscopy (HR-TEM), Nitrogen physisorption studies, X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), X-ray photon electron spectroscopy (XPS) and ζ-potential studies...
October 4, 2016: International Journal of Pharmaceutics
Ulysse Gimenez, Adriana-T Perles-Barbacaru, Arnaud Millet, Florence Appaix, Michele El-Atifi, Karin Pernet-Gallay, Boudewijn van der Sanden, François Berger, Hana Lahrech
Monitoring glioma cell infiltration in the brain is critical for diagnosis and therapy. Using a new glioma Glio6 mouse model derived from human stem cells we show how diffusion tensor imaging (DTI) may predict glioma cell migration/invasion. In vivo multiparametric MRI was performed at one, two and three months of Glio6 glioma growth (Glio6 (n = 6), sham (n = 3)). This longitudinal study reveals the existence of a time window to study glioma cell/migration/invasion selectively. Indeed, at two months only Glio6 cell invasion was detected, while tumor mass formation, edema, blood-brain barrier leakage and tumor angiogenesis were detected later, at three months...
September 15, 2016: NMR in Biomedicine
Afonso C Silva
The common marmoset (Callithrix jacchus) is a small New World monkey that has gained significant recent interest in neuroscience research, not only because of its compatibility with gene editing techniques, but also due to its tremendous versatility as an experimental animal model. Neuroimaging modalities, including anatomical (MRI) and functional magnetic resonance imaging (fMRI), complemented by two-photon laser scanning microscopy and electrophysiology, have been at the forefront of unraveling the anatomical and functional organization of the marmoset brain...
October 5, 2016: Developmental Neurobiology
Alexander Dvornikov, Enrico Gratton
Imaging depth in turbid media by two-photon fluorescence microscopy depends on the ability of the optical system to detect weak fluorescence signals. We have shown that use of a wide area detector in transmission geometry allows increasing imaging depth in turbid media due to efficient photon collection. Compared to the conventional epi-detection scheme used in most commercial microscopes, the transmission detector was found to be 2-3 orders of magnitude more sensitive when used for in depth imaging in scattering samples simulating brain optical properties...
September 1, 2016: Biomedical Optics Express
Ilyas Saytashev, Rachel Glenn, Gabrielle A Murashova, Sam Osseiran, Dana Spence, Conor L Evans, Marcos Dantus
Red blood cells (RBC) in two-photon excited fluorescence (TPEF) microscopy usually appear as dark disks because of their low fluorescent signal. Here we use 15fs 800nm pulses for TPEF, 45fs 1060nm pulses for three-photon excited fluorescence, and third harmonic generation (THG) imaging. We find sufficient fluorescent signal that we attribute to hemoglobin fluorescence after comparing time and wavelength resolved spectra of other expected RBC endogenous fluorophores: NADH, FAD, biliverdin, and bilirubin. We find that both TPEF and THG microscopy can be used to examine erythrocyte morphology non-invasively without breaching a blood storage bag...
September 1, 2016: Biomedical Optics Express
Shuai Guo, Chunhui Niu, Liang Liang, Ke Chai, Yaqing Jia, Fangyin Zhao, Ya Li, Bingsuo Zou, Ruibin Liu
Based on a silica sol-gel technique, highly-structurally ordered silica photonic structures were fabricated by UV lithography and hot manual nanoimprint efforts, which makes large-scale fabrication of silica photonic crystals easy and results in low-cost. These photonic structures show perfect periodicity, smooth and flat surfaces and consistent aspect ratios, which are checked by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, glass substrates with imprinted photonic nanostructures show good diffraction performance in both transmission and reflection mode...
October 4, 2016: Scientific Reports
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