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The Moscone Center
San Francisco, California, United States
28 January - 2 February 2017
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Brain Presentations

Spectroscopy, Microscopy, Imaging, Nanobiophotonics, and LASE
(ordered by conference and paper number)

Imaging deep in the brain using dendritic upconverting nanoparticles
Paper 10497-37

Author(s):  Nelda Antonovaité, Vrije Univ. Amsterdam (Netherlands), et al.
Conference 10497: Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues XVI
Session 6: Spectral Imaging I

To investigate the structure-stiffness relation of brain tissue we have conducted dynamic indentation-controlled mapping on isolated horizontal mouse brain sections. We report highly heterogeneous viscoelasticity maps of hippocampus where regions with specific mechanical properties correlate with structurally distinct layers. By estimating the mean stiffness and the density of nuclei of eleven anatomical regions, we found that more densely packed cell layers have lower stiffness. Our study presents a novel indentation method able to map viscoelastic properties at a high spatial resolution, which leads to a better understanding of the relation between brain tissue composition and stiffness in physiological and pathological conditions.

Polymer dots enable deep in vivo multiphoton fluorescence imaging of cerebrovascular architecture
Paper 10498-103

Author(s):  Mirna El Khatib, Perelman School of Medicine, Univ. of Pennsylvania (United States), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session PSun: Posters-Sunday

Lanthanide-based upconverting nanoparticles (UCNP's) are able to efficiently convert near infrared excitation energy into visible or higher energy near infrared light, thereby presenting an attractive platform for construction of biological imaging agents. However, lack of solubility and difficulty in their surface modifications hampered development of UCNP's as general imaging agents. Previously, we have demonstrated that shape-persistent polyglutamic dendrimers, exhibiting multiple carboxylate groups as their termini, are of tight bind to UCNP surfaces, thus stabilizing them in aqueous solutions and converting them into bio-compatible imaging probes.1 However, solubility imparted by polycarboxylates was found to be negatively impacted by the presence of divalent metal cations and various macromolecules (proteins, lipids etc), which are abundant in biological systems. In this work, we report extension of our approach using Janus-type dendrimers, in which one half of the dendrimer surface features carboxylates for binding to UCNP surfaces and another is highly hydrophilic, but neutral as a result of extensive PEG-ylation. The new dendritic UCNP's proved to have superior stability and biocompatibility and allowed high-resolution imaging of brain vasculature in mice up to 1 mm deep into the cortex by means of multiphoton microscopy with continuous-wave infrared excitation sources. The synthesis of PEGylated Janus-dendrimers as well as the method of dendrimerization of UCNP's has been optimized and scaled up, thus presenting a new generally applicable methodology. References 1 Esipova, T. V.; Ye, X.; Collins, J. E.; Sakadžić, S.; Mandeville, E. T.; Murray, C. B.; Vinogradov, S. A. Proc. Natl. Acad. Sci. U.S.A. 2012, 109, 20826. Support of the NIH grant EB018464 is gratefully acknowledged.

Scanless three-dimensional excitation and detection by selective access multifoci multiphoton microscopy
Paper 10498-40

Author(s):  Aram Zeytunyan, Newport Corp. (United States), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session 8: Technology and In Vivo Imaging II

We developed a module for dual-output wavelength lasers that facilitates multiphoton imaging and spectroscopy experiments and enables hyperspectral imaging with spectral resolution of up to 5 cm-1. High spectral resolution is achieved by employing spectral focusing, using grating pairs to control the chirps in each laser beam, which allows matching the spectral resolution and the linewidths of the Raman lines of interest. We report the results of spectral focusing CARS and SRS microscopy experiments in various test samples. We also discuss the feasibility of using the developed module for variety of multimodal imaging and spectroscopy applications.

In vivo three-photon imaging of deep mouse cerebellum
Paper 10498-41

Author(s):  Yi Xue, Massachusetts Institute of Technology (United States), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session 8: Technology and In Vivo Imaging II

A single neuron has approximately ten thousand excitatory synapses; monitoring signal initiation and propagation requires near simultaneous imaging of all these synaptic sites and other strategic locations along the dendrite. We demonstrate selective access multifocal multiphoton microscopy, which improves imaging speed and signal-to-noise ratio. A spatial light modulator is used to generate multifocal excitation in 3D. Importantly, a Gaussian-Laguerre phase plate is used to detect fluorescence from these spots simultaneously throughout the volume. We illustrate the performance of this system by recording calcium dynamics of cultured neurons simultaneous at 10Hz from 149 planar locations distributed across the field of view. Simultaneous excitation and detection at multiple locations in 3D is also demonstrated. This “3D imaging in a single shot” strategy allows strictly-synchronized dynamic recording, which is used for accurate determination of signal propagation speed across different dendrites.

Frequency-multiplexed multi-beam two photon imaging for recording of Ca2+ signals in neural ensembles
Paper 10498-43

Author(s):  Mengran Wang, Cornell Univ. (United States), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session 8: Technology and In Vivo Imaging II

We demonstrate three-photon microscopy (3PM) in imaging mouse cerebellum as deep as 1mm with both green and red fluorescence labeled mice. Based on quantitative comparison, we show two-photon microscopy (2PM) is limited in imaging depth due to the faster signal decay from absorption and scattering, and low signal-to-background ratio (SBR) when imaging deep in non-sparsely labeled brains. By comparing the third harmonic generation (THG) signal with decay curve, we show the difference in effective attenuation lengths at different depths is due to the non-uniform distribution of myelinated fibers in cerebellum, which adds complexity for imaging in this brain region.

Improving sensitivity of stimulated Raman scattering microscopy with cavity dumped optical parametric oscillator and its application in brain imaging
Paper 10498-47

Author(s):  Dmitri A. Tsyboulski, Allen Institute (United States), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session 9: Coherent Raman I

We present an improved frequency-multiplexed two photon imaging scheme that utilizes amplitude modulation of femtosecond laser pulses in the MHz range to generate and tag multiple excitation beam and the corresponding fluorescence signals with specific frequencies. Frequency tags are generated with an interferometric setup including acousto-optic deflectors (AODs) to achieve precise spatial overlap of fs pulses with acoustically-shifted frequencies. The imaging performance of the instrument for analyzing of cell morphology and recording of Ca+ signals in neural ensembles will be discussed.

Multi-photon photoacoustic imaging
Paper 10498-64

Author(s):  Wenlong Yang, Harvard Univ. (United States), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session 12: Technology and In Vivo Imaging III

Stimulated Raman scattering (SRS) microscopy is a label-free nonlinear-optical imaging method based on the vibrational spectroscopy of molecules. SRS has been extensively used in label-free histology, lipid, myelin imaging, and other biomedical researches, however, its application is limited by its signal to noise ratio. We developed a new laser source to increase the nonlinear signal. Specifically, the new laser source includes two synchronize-pumped cavity-dumped optical parametric oscillators that reduce laser reputation rate to around 3 MHz while generating an average power of around 200 mW. Here, the efforts towards imaging neurotransmitter in mouse brain with the new SRS imaging system will be presented.

In vivo, two-color multiphoton microscopy using a femtosecond diamond Raman laser
Paper 10498-65

Author(s):  Depeng Wang, Univ. at Buffalo (United States), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session 12: Technology and In Vivo Imaging III

Multi-photon photoacoustic imaging (MP-PAI) is a new technique that allows detection of visible-light-absorbing contrast agents in deep tissue. MP-PAI is based on the principle of multiphoton transformation: upon irradiation by near infrared light, upconversion materials will convert long wavelength photons into shorter wavelength photons, creating in situ visible light sources for photoacoustic signal excitation. We validated the technique in both pulsed- and continuous-wave-based photoacoustic setups. The pulsed setup utilized a two-photon absorbing dye, while the continuous-wave setup used up-converting inorganic nanoparticles. In both systems, we successfully detected multi-photon photoacoustic signals underneath chicken breast tissue.

Adaptive optics plug-and-play setup for high-resolution microscopes with multi-actuator adaptive lens
Paper 10498-67

Author(s):  Jeremy W. Jarrett, The Univ. of Texas at Austin (United States), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session 12: Technology and In Vivo Imaging III

Multiphoton microscopy is an essential tool for detailed study of neurovascular structure and function. We have developed a relatively simple and low cost diamond Raman laser pumped with a ytterbium fiber amplifier. The dual output system generates excitation light at 1055 nm (pump wavelength) and 1240 nm (first Stokes emission of diamond laser) which, when temporally and spatially overlapped, yield an effective two-color excitation wavelength of 1140 nm. We demonstrate multicolor, multiphoton imaging of a myriad of dyes and fluorescent proteins—including genetically encoded calcium indicators—in engineered multicellular spheroids and in vivo in mouse cortex.

Femtosecond semiconductor disk lasers: a promising tool for the future of multiphoton imaging
Paper 10498-76

Author(s):  Martino Quintavalla, Univ. degli Studi di Padova (Italy), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session PSun: Posters-Sunday

Adaptive Optics (AO) has revealed as a very promising technique for high resolution microscopy, where the presence of optical aberrations can easily compromise the image quality. Typical AO systems however, are almost impossible to implement on commercial microscopes. We propose a simple approach by using a Multi-actuator Adaptive Lens (MAL) that can be inserted right after the objective and works in conjunction with an image optimization software allowing for a wavefront sensorless correction. We presented the results obtained on several commercial microscopes among which a confocal microscope, a fluorescence microscope, a light sheet microscope and a multiphoton microscope

Non-planar microscopy via multi-pupil wavefront shaping
Paper 10498-79

Author(s):  Florian M. Emaury, ETH Zurich (Switzerland), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session PSun: Posters-Sunday

We demonstrate the suitability of femtosecond semiconductor disk lasers for multiphoton microscopy with several common in-vivo imaging experiments in both Drosophila larvae and mice using a variety of fluorophores (including mKate2, tdTomato, Texas Red, OGB-1, and R-CaMP1.07) and for endogenous second-harmonic generation. With a laser generating 170-fs pulses at a center wavelength of 1027 nm and a repetition rate of 1.63 GHz, we also performed a quantitative comparison with a standard Ti:Sapphire showing that equivalent image quality can be obtained without additional bleaching. Such compact and potentially low-cost femtosecond optically pumped semiconductor disk lasers are promising sources for bio-imaging applications.

Improvement of two-photon microscopic imaging in deep regions of living mouse brains by utilizing a light source based on an electrically controllable gain-switched laser diode
Paper 10498-89

Author(s):  Lingjie Kong, Tsinghua Univ. (China), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session PSun: Posters-Sunday

High-speed volumetric imaging techniques are desired for recording biological dynamics in 3D, which, however, usually scan the whole volume including the regions of non-interest and lead to inefficient data acquisition. Here we develop a non-planar microscopy via multi-pupil wavefront shaping. We construct an array of pupil images on a spatial light modulator, with each pupil corresponding to a sample region. This enables us not only to compensate wavefront aberration over a large field-of-view, but also to target an arbitrary depth-of-interest for each region. We show its applications in functional imaging of neural networks and dynamical imaging of blood vascular dilation.

Large scale serial two-photon microscopy to investigate local vascular changes in whole rodent brain models of Alzheimer's disease
Paper 10498-92

Author(s):  Kazuaki Sawada, Hokkaido Univ. (Japan), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session PSun: Posters-Sunday

To improve the penetration depth of in vivo two-photon microscopy for H-line living mouse brains, we previously introduced a 1064 nm gain-switched laser diode based high-power light source (repetition rate: 10 MHz). However, high-power laser light irradiations induced severe damages in living mouse brains frequently. To increase fluorescent signals with avoiding invasions, we here evaluated effects of the excitation laser parameters such as the repetition rate or the peak power. As the result, EYFP fluorescent signals from neurons were increased by about twice when the repetition rate was decreased from 10 MHz to 5 MHz at the same moderate average powers.

High contrast light field microscopy with single-objective selective volume illumination
Paper 10499-18

Author(s):  Patrick Delafontaine-Martel, Ecole Polytechnique de Montréal (Canada), et al.
Conference 10499: Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XXV
Session 6: Polarization and Light Field Microscopy

Whole mouse brains were imaged by an automated serial histology apparatus combined with a two-photon microscope. Complete image reconstruction from serial tiles were performed with Laplacian diffusion. Comparison between Alzheimer model and wild type mouse brains were studied to evaluate changes in vascular densities at 2, 4.5 and 8 months old. After a FITC-gelatin perfusion process, hippocampus and prefrontal cortex were segmented digitally from a complete template brain. Otsu local threshold, Sato filters and skeletonization were used and an in-plane cylindrical model of vasculature was applied to compute the density of the concerned regions of the brain.

Comparison of excitation wavelengths for in vivo deep imaging of mouse brain
Paper 10498-110

Author(s):  Ahmed Hassan, The Univ. of Texas at Austin (United States), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session PSun: Posters-Sunday

Polymer dots (pdots) represent a class of highly fluorescent probes with exceptional photophysical characteristics. We characterize the properties of three pdot variants and demonstrate deep neuroimaging of pdot-labeled mice. We measure their power dependence and action cross-sections over a wide spectrum and discover they exceed the brightness of traditional probes such as quantum dots. Furthermore, we show their brightness enables two-photon imaging of cerebrovasculature at a cortical depth of 850 µm. Their broad absorption permits stimulation at longer wavelengths that approach an ideal biological imaging wavelength near 1,300 nm, resulting in substantial improvements in signal-to-background ratio and extended imaging depths.

Module for multiphoton high-resolution hyperspectral imaging and spectroscopy
Paper 10498-19

Author(s):  Mengran Wang, Cornell Univ. (United States), et al.
Conference 10498: Multiphoton Microscopy in the Biomedical Sciences XVIII
Session 4: Technology and In Vivo Imaging I

The attenuation of the excitation laser power is a major obstacle in deep imaging of biological tissue. Simple analysis shows that the effective attenuation length of the excitation power in biological tissue depends on tissue scattering and absorption. Here we perform a systematic comparison of the effective attenuation lengths at excitation wavelengths of 1450 nm, 1500 nm, 1550 nm and 1680 nm through three-photon imaging of mouse brain vasculature in vivo, providing strong evidence in confirming that the wavelength windows of 1300 nm and 1700 nm are optimum for deep imaging of the mouse brain.

Imaging a seizure model in zebrafish with structured illumination light sheet microscopy
Paper 10499-38

Author(s):  Sara Madaan, Univ. of California, Los Angeles (United States), et al.
Conference 10499: Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XXV
Session 11: Multidimensional Imaging of Biological Systems

Low cost light-sheet microscopy for whole brain imaging
Paper 10499-44

Author(s):  Yang Liu, The Univ. of Georgia (United States), et al.
Conference 10499: Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XXV
Session 12: New Methods in Microscopy

Zebrafish are a promising vertebrate model for elucidating how neural circuits generate behavior under normal and pathological conditions. Because of their small size and transparency, zebrafish embryos are ideal for imaging seizure activity using calcium indicators. We describe work on our lab to use light-sheet microscopy for high-speed long-time imaging of neural activity in wildtype and mutant zebrafish. We show that, with light-sheet microscopy, neural activity can be recorded at 23 frames per second in two-colors for over 10 minutes allowing us to capture rare seizure events in mutants. We have further implemented structured illumination to increase resolution in both the y and z directions during high-speed imaging at an effective frame rate of over 15 frames per second.

Development of chair-side evaluation system of swallowing discomfort of denture wearers
Paper 10501-19

Author(s):  Manish Kumar, Northwestern Univ. (United States), et al.
Conference 10501: Optical Diagnostics and Sensing XVIII: Toward Point-of-Care Diagnostics
Session 5: Near Infrared Sensing and Monitoring In Vivo

Light-sheet microscopy is a useful technique for high-resolution and fast imaging of biological samples. Conventional light-sheet microscopy systems utilize orthogonally placed microscope objectives, where one objective creates the light-sheet for optical sectioning and another forms high-resolution image of this section on a camera. Then volumetric imaging is made possible by translating the sample in the direction perpendicular to the light-sheet. Here, we make a very low cost light-sheet microscopy system capable of imaging entire optically cleared mouse brains at single cell resolution. We reduce the cost by replacing laser with a laser-diode, utilizing low-cost dry objectives and custom-built 1D translation stage.

Adaptive micro endoscopy using liquid crystal lenses with segmented electrodes
Paper 10502-1

Author(s):  Keisuke Matsumoto, Meiji Univ. (Japan), et al.
Conference 10502: Adaptive Optics and Wavefront Control for Biological Systems IV
Session 1: Wavefront Shaping Devices: Deformable Mirrors, Spatial Light Modulators

We used portable near-infrared spectroscopy and investigated cerebral hemodynamic parameters to best differentiate the discomfort intensity related to swallowing behavior in healthy subjects wearing different types of simulated dentures. The simulated dentures had a palatal bar along with the anterior, middle or posterior areas of the upper jaw. The cumulative values of mean oxyhemoglobin and deoxyhemoglobin concentration (area-under-the-curve: AUC) were tested as indices of the intensity of swallowing discomfort. AUC of deoxyhemoglobin concentration calculated for 10 s post-swallowing event from the left frontopolar prefrontal cortex showed the best correlation with the subjective rating of discomfort in swallowing with dentures.

An add-on adaptive optical module for laser scanning microscopy
Paper 10502-14

Author(s):  Tigran Galstian, Ctr. d'Optique, Photonique et Laser (Canada), et al.
Conference 10502: Adaptive Optics and Wavefront Control for Biological Systems IV
Session 4: AO for Microscopy and Optical Coherence Tomography III

Liquid crystalline (LC) materials are well-known materials for electro optics applications such as flat panel displays. Another interesting development, involving LCs, was the electrically variable lens that already had several commercial applications. Their quality can be very high and our team has recently demonstrated that they can be used in endoscopes for the study of deep regions of the brain. We describe electrically variable LC lenses with segmented electrodes that enable adaptive optical capability, including the creation of a dynamic lens, prism, astigmatism and coma. This could be used to compensate various wavefront deformations in biophotonic systems.

Large-field-of-view imaging by multi-pupil adaptive optics
Paper 10502-9

Author(s):  Stephen A. Burns, Indiana Univ. (United States), et al.
Conference 10502: Adaptive Optics and Wavefront Control for Biological Systems IV
Session 3: AO for Microscopy and Optical Coherence Tomography II

Adaptive optics retinal imaging is of increasing importance in understanding the impact of retinal and systemic diseases. We present strategies for cellular imaging in the presence of the small pupils, developing cataracts, and post cataract issues that are common in patients with retinal disease. These include improvements in both adaptive optics control and in the sampling of light scattered from the retina. Adaptive optics control is improved by using local image quality metrics on the pupil of the eye to maintain mirror positions. Retinal image quality is controlled using spatial light modulators to sample the retinal point spread function.

Reflection gradient light interference microscopy (epi-GLIM) for label-free imaging of bulk specimens
Paper 10503-14

Author(s):  Lingjie Kong, Tsinghua Univ. (China), et al.
Conference 10503: Quantitative Phase Imaging IV
Session 4: QPI Methodologies III

Optical microscopy is susceptible to optical aberrations and scattering in biological tissues, which degrade both the spatial resolution and penetration depth. To correct the inhomogeneity-induced wavefront distortion, adaptive optics is successfully employed for deep-tissue imaging. However, due to the spatially varied wavefront distortion, the field-of-view (FoV) of effective compensation in conventional methods is constrained. Here we developed multi-pupil adaptive optics (MPAO) to enlarge the FoV, in which an array of pupil images is constructed on a spatial light modulator with each pupil corresponding to a sample region. We applied MPAO to in vivo structural and functional imaging in the mouse brain.

Wavefront engineering in living tissue using time-reversed ultrasonically encoded (TRUE) focusing for deep-tissue optogenetic modulation
Paper 10502-35

Author(s):  Ichun Anderson Chen, Howard Hughes Medical Institute (United States), et al.
Conference 10502: Adaptive Optics and Wavefront Control for Biological Systems IV
Session 8: Applications of Time-Reversal in Biological Imaging, Optical Phase Conjugation

SCAPE microscopy for high-speed 3D imaging of living tissues
Paper 10502-38

Author(s):  Joshua Brake, California Institute of Technology (United States), et al.
Conference 10502: Adaptive Optics and Wavefront Control for Biological Systems IV
Session 9: Shaped Beams for Light Sheet and Structured Illumination Microscopy

Recent work in the field of wavefront engineering has demonstrated that by properly shaping the input light field, light can be noninvasively focused to desired locations deep inside strongly scattering media such as fog and biological tissue. Unfortunately, extending these methods to living tissue has a number of challenges, related to the requirements for noninvasive guidestar operation, speed, and focusing fidelity. In this presentation, I will discuss the results of our recent work to apply time-reversed ultrasonically encoded (TRUE) focusing for optogenetic modulation, which enables enhanced optogenetic stimulation deep in tissue with a 4-fold spatial resolution improvement in 800-micron thick acute brain slices compared to conventional focusing, and summarize future directions for wavefront engineering in biomedicine.

Two-photon holographic imaging and optogenetics of neural circuits
Paper 10502-40

Author(s):  Elizabeth M. Hillman, Columbia Univ. (United States), et al.
Conference 10502: Adaptive Optics and Wavefront Control for Biological Systems IV
Session 9: Shaped Beams for Light Sheet and Structured Illumination Microscopy

Swept confocally aligned planar excitation (SCAPE) microscopy is a single-objective light sheet method capable of very high speed 3D imaging. Images are formed by sweeping an oblique sheet of light through the intact, unmounted sample in an epi-fluorescence geometry, while descanning ensures that a camera stays focused onto the light sheet without requiring any physical translation of the objective or sample. Latest developments in SCAPE microscopy will be described including imaging of large 3D fields of view at over 100 volumes per second, and improved performance for a diverse array of in-vivo samples including Drosophila, zebrafish and awake, behaving mice.

Spatio-temporal volumetric light shaping for two-photon optogenetics
Paper 10502-43

Author(s):  Weijian Yang, Columbia Univ. (United States), et al.
Conference 10502: Adaptive Optics and Wavefront Control for Biological Systems IV
Session 10: Channel Demixing for Endoscopy/Fibers I

We discuss our recent progress on holographic imaging and optogenetics, by the usage of spatial light modulators (SLMs) in two-photon microscopes. The SLM generates a 3D holographic excitation pattern, which is projected on the sample for multi-target imaging or photostimulation. We demonstrated recording neural activity in groups of neurons in zebrafish larva across 3D volume or neural activity across multiple planes in mice cortex and Hydra. Besides 3D imaging, we successfully performed 3D optogenetics where groups of target neurons on mice cortex were simultaneously photostimulated. SLM-based two-photon microscopy establishes an all-optical platform to study the neural circuits in 3D.

Robust adaptive optics systems for retinal imaging
Paper 10502-8

Author(s):  Dimitrii Tanese, Univ. Paris Descartes (France), et al.
Conference 10502: Adaptive Optics and Wavefront Control for Biological Systems IV
Session 2: AO for Microscopy and Optical Coherence Tomography I

The advent of novel molecular tools, such as light-sensitive channels and reporters, opened new ways to manipulate and control neuronal activity. Their full exploitation requires illumination approaches capable of selectively targeting multiple cells. Here we report a novel optical scheme to generate 3D illumination patterns based on the spatio-temporal modulation of a two-photon excitation beam. By multiplexing a temporally focused bi-dimensional pattern over multiple positions, we generate several tens of axially confined spots in an extended volume. We validate this approach by performing multicell volumetric excitation of photoactivatable GCaMP (PA-GCaMP) in fruit flies and Kaede photoconversion in zebrafish larvae.

Multimodal quantitative phase digital holographic microscopy to identify disease-specific cell phenotypes
Paper 10503-45

Author(s):  Mikhail E. Kandel, Univ. of Illinois (United States), et al.
Conference 10503: Quantitative Phase Imaging IV
Session 11: QPI Clinical Applications I

Gradient Light Interference Microscopy (GLIM) is a phase-shifting technique that upgrades a conventional differential interference contrast (DIC) microscope to produce quantitative phase images. Benefiting from equally matched beams, fully open microscope condenser, as well as coherence gating due to the removal of non-interferometric terms upon phase-retrieval, GLIM has the potential to enable studies of mesoscopic structure hundreds of microns thick. Nevertheless, many such biological samples are much too big to completely transmit light, requiring the use of reflection microscopy. Here we present our early work on constructing a new reflection mode GLIM microscope designed to image thick biological structures, as well as a detailed comparison between transmitted vs reflected light modalities for a number of calibration samples.

HoloConvNet: A deep learning framework for holographic screening of anthrax spores
Paper 10503-70

Author(s):  Pierre P. Marquet, Institut Univ. en Santé Mentale de Québec (Canada), et al.
Conference 10503: Quantitative Phase Imaging IV
Session PMon: Posters-Monday

Quantitative phase imaging has recently emerged as a powerful technique in the field of cell imaging allowing to non-invasively explore cell structure and dynamics. However, the intrinsic noninvasive phase signal has difficulties identifying specific cellular processes. To overcome this drawback, we have developed multimodal imaging techniques by combining QPM approaches, including multi-wavelength, tomography based on digital holographic microscopy (DHM), with fluorescence microscopy, electrophysiology in particular. These multimodal quantitative phase DHM techniques have been systematically used to explore various types of human cells collected from patients suffering from major psychiatric disorders including schizophrenia aiming at identifying and isolating disease-specific cell phenotypes

Real-time halo correction in common-path QPI
Paper 10503-97

Author(s):  YoungJu Jo, KAIST (Korea, Republic of), et al.
Conference 10503: Quantitative Phase Imaging IV
Session PMon: Posters-Monday

Most of the conventional methods for screening of Bacillus anthracis spores have suffered from limited sensitivity and/or specificity to cope with realistic settings. Here, we present an optical method for rapid screening of anthrax spores with single-spore sensitivity and sub-genus specificity. We designed a deep convolutional neural network, named HoloConvNet, which enables end-to-end training of species classifiers that outperforms all previous methods. The proposed framework is readily applicable to various single-cell identification problems; we demonstrated diagnosis of the pathogen Listeria monocytogenes with no modification. Our demonstration would facilitate novel approaches at the interface between quantitative phase imaging and deep learning.

Multiphoton microscopy for deep brain imaging
Paper 10504-11

Author(s):  Mikhail E. Kandel, Univ. of Illinois (United States), et al.
Conference 10504: Biophysics, Biology and Biophotonics III: the Crossroads
Session 3: New Technologies in Medical Diagnostics

Phase contrast is by far the most popular method used in the routine maintenance and inspection of mammalian cell cultures. Nevertheless, phase contrast, as well as most common-path modalities suffer from a “halo” like glow making quantitative analysis difficult. This effect is particularly pronounced around sharp discontinuities in the scattering potential, such as typically found surrounding the nuclei of adherent cells. Recent advances in modeling image formation have shown that this artifact is due to the distribution of plane waves in the illumination, i.e., the limited spatial coherence of the illumination. Yet, the same incoherent illumination is responsible for superior sensitivity of the phase contrast modality. Thus, microscope manufacturers face a difficult choice between incoherent (high-detail) and coherent (low-detail) optimized systems. Here, we propose a numerical processing technique to resolve this challenge, by carefully demodulating corrupt low-frequency data with high-fidelity high-frequency data in a way that maintains the quantitative nature of the high-frequency content. With our technique, we are able to remove halo artifacts at video rates, requiring no manual interaction or complicated point spread function measurements. To validate our approach, we study standard samples, tissue biopsies, and time-lapse growth rates of a neuron culture.

High throughput 3D microscopy for in vivo fluorescence imaging
Paper 10505-30

Author(s):  Chris Xu, Cornell Univ. (United States), et al.
Conference 10505: High-Speed Biomedical Imaging and Spectroscopy III: Toward Big Data Instrumentation and Management
Session 8: High-throughput In Vivo Imaging

In this talk, the fundamental challenges of deep tissue, high-resolution optical imaging are discussed. New technologies for in vivo structural and functional imaging of mouse brain using long wavelength excitation and 3-photon microscopy will be presented. We will discuss the requirements for imaging the dynamic neuronal activity at the cellular level over a large area and depth in awake and behaving animals, and illustrate several applications for deep tissue imaging. We will speculate on the possible future directions to further improve the imaging depth and speed in biological tissues.

Multifunctional gold nanoparticles for diagnosis of Alzheimer's disease
Paper 10506-41

Author(s):  Meng Cui, Purdue Univ. (United States), et al.
Conference 10506: Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XV
Session PTue: Posters-Tuesday

In bioimaging applications, the features of interest are generally distributed in 3D. How to effectively and efficiently perform measurement in 3D has become an important topic that can benefit a wide range of applications, such as cell biology, immunology, neuroscience, and development biology. In this presentation, we will discuss the latest techniques developed in our lab that can work well deep in live tissues.

Labeling and tracking exosomes within the brain using gold nanoparticles
Paper 10506-44

Author(s):  Renana Opochinsky, Bar-Ilan Univ. (Israel), et al.
Conference 10506: Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XV
Session PTue: Posters-Tuesday

One of the main pathologies of Alzheimer's disease (AD) is accumulation of amyloid-β (Aβ) in the brain. Despite the advancement in imaging technologies, early diagnosis of AD remains a major challenge. Therefore, new approaches for amyloid imaging are highly desirable. This work presents a new theranostic strategy for molecular CT imaging and therapy of AD, based on multifunctional gold-nanoparticles that can penetrate the blood-brain-barrier and selectively target early Aβ oligomers. Our method showed significant therapeutic effect in-vitro and efficient Aβ detection in-vitro and in-vivo. We expect that this innovative nanoparticle-based approach will provide an effective solution for AD diagnosis and therapy.

Time-gated background-free imaging of temperature
Paper 10508-8

Author(s):  Oshra Betzer, Institute of Nanotechnology and Advanced Materials, Bar-Ilan Univ. (Israel), et al.
Conference 10508: Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications X
Session 2: Molecular and Physiological Imaging Strategies and Probes

Exosomes are evolving as effective therapeutic tools for various pathologies. However, to promote exosomes' therapy development, especially for brain pathologies, a better understanding of their trafficking, pharmacokinetics and bio-distribution is needed. Herein, we developed a method for non-invasive in-vivo neuroimaging of mesenchymal stem cell (MSC)-derived exosomes, based on computed tomography (CT) imaging with glucose-coated gold nanoparticle (GNP) labeling. We established the optimal parameters for exosome labeling and neuroimaging, wherein 5nm GNPs enhanced labeling, and intranasal administration resulted superior brain accumulation. In a focal ischemia mouse model tracking intranasaly-administered GNP-labeled exosomes revealed specific accumulation and prolonged presence at the lesion area. We propose that this in-vivo neuroimaging technique can serve as a general platform for brain-theranostics.

Surface plasmon resonance based ring resonator for biosensing applications
Paper 10509-15

Author(s):  Sergei A. Vinogradov, Univ. of Pennsylvania (United States), et al.
Conference 10509: Plasmonics in Biology and Medicine XV
Session 4: Plasmonics, Sensing and Bioanalytical Applications

We report new optical probes for imaging temperature that emit luminescence on the microsecond time scale from two excited electronic states existing in thermal equilibrium with one another. While the decay rate(s) are subject to various quenching processes (e.g. by molecular oxygen), the ratio of the decay integrated intensities responds only to temperature. The new probes have high multiphoton absorption cross-sections, while both luminescence decays (from the two states) can be measured in parallel, as they occur different wavelengths. Thus, the new probes allow for simultaneous depth-resolved two-photon imaging of temperature and oxygen in living tissues.

200-W single frequency laser based on short active double clad tapered fiber
Paper 10512-81

Author(s):  Lokendra Singh, DIT Univ. (India), et al.
Conference 10512: Fiber Lasers XV: Technology and Systems
Session Tue: Posters-Tuesday

This work is based on surface plasmon confinement in nano-slots of double slot ring resonator structure, which can employ for diverse liquid sensors. The structure is depicted using hybrid plasmonic waveguides due to its absolute attribute of longer propagation length. The structure of resonator is delineated in such a way that optical energy is extreme mainly in narrow slots of two metallic layers. This type of resonator can be easily fabricated using silicon on insulator platform whose technique has been also discussed. The sensitivity of device can be achieved up to 900 nm/RIU for biomolecules.

Laser microstructured diamond electrode arrays for bionic eye applications
Paper 10520-10

Author(s):  Christophe Pierre, ALPhANOV (France), et al.
Conference 10520: Laser-based Micro- and Nanoprocessing XII
Session 3: Laser Micro/Nano Structuring on Flexible Substrates

In this paper, the generation of stable 200W with diffraction limited output, and narrow linewidth (Δν<30kHz) are reported. A powerful preamplifier permits to amplify a 15mW single frequency laser diode up to 3.5W and acts as seeder for the tapered fiber. A counter propagating 400W multimode laser diode at 976nm is used for population inversion. With this short active tapered, 200W of laser is extracted with an efficiency of 60%. No sign of ASE is visible (ratio signal on ASE more than 50 dB). A M² measurement gives a value of

Drilling progress of deep holes in tool steel using high energy picosecond laser pulses
Paper 10520-31

Author(s):  Steven Prawer, The Univ. of Melbourne (Australia), et al.
Conference 10520: Laser-based Micro- and Nanoprocessing XII
Session 7: Laser Micro/Nano Structuring on Metals

Retinal implants that restore some degree of vision to people suffering from retinal degenerative diseases are now a reality. But their performance is far from ideal and recipients cannot yet use these devices to read large print or recognize the faces of loved ones. The use of carbon based materials such as diamond and graphene is opening up new opportunities for novel devices with enhanced performance. These materials are often hard to process by traditional chemical etching techniques. Laser processing provides the key technique to be able to sculpt a new generation of retinal implants made entirely of diamond.

Important Dates

Abstracts Due
17 July 2017

Author Notification
25 September 2017

Manuscripts Due
See Individual Conferences

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Journal of Biomedical Optics

Journal of Biomedical OpticsPublishes peer-reviewed papers that utilize modern optical technology for improved health care and biomedical research.