Nonlinear Endomicroscopy for Two-photon Autofluorescence Imaging of Biological Tissues

2009 ◽  
Author(s):  
Yicong Wu ◽  
Ming-Jun Li ◽  
Xingde Li
Keyword(s):  
Biological Tissues ◽  
Autofluorescence Imaging ◽  
Two Photon

Age-related structural abnormalities in the human retina-choroid complex revealed by two-photon excited autofluorescence imaging

2007 ◽  
Vol 12 (2) ◽  
pp. 024012 ◽  
Author(s):  
Meng Han ◽  
Guenter Giese ◽  
Steffen Schmitz-Valckenberg ◽  
Almut Bindewald-Wittich ◽  
Frank G. Holz ◽  
...  
Keyword(s):  
Human Retina ◽  
Autofluorescence Imaging ◽  
Two Photon ◽  
Age Related ◽  
Structural Abnormalities

scholarly journals Two-Photon Autofluorescence Imaging Reveals Cellular Structures Throughout the Retina of the Living Primate Eye

2016 ◽  
Vol 57 (2) ◽  
pp. 632 ◽  
Author(s):  
Robin Sharma ◽  
David R. Williams ◽  
Grazyna Palczewska ◽  
Krzysztof Palczewski ◽  
Jennifer J. Hunter
Keyword(s):  
Cellular Structures ◽  
Autofluorescence Imaging ◽  
Two Photon

scholarly journals Design and Demonstration of a Microbiaxial Optomechanical Device for Multiscale Characterization of Soft Biological Tissues with Two-Photon Microscopy

2011 ◽  
Vol 17 (2) ◽  
pp. 167-175 ◽  
Author(s):  
Joseph T. Keyes ◽  
Stacy M. Borowicz ◽  
Jacob H. Rader ◽  
Urs Utzinger ◽  
Mohamad Azhar ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Tissue Sample ◽  
Imaging Techniques ◽  
High Stress ◽  
Viscoelastic Behavior ◽  
Biological Tissues ◽  
The Body ◽  
Two Photon ◽  
Biomechanical Response ◽  
Tissue Specimens

AbstractThe biomechanical response of tissues serves as a valuable marker in the prediction of disease and in understanding the related behavior of the body under various disease and age states. Alterations in the macroscopic biomechanical response of diseased tissues are well documented; however, a thorough understanding of the microstructural events that lead to these changes is poorly understood. In this article we introduce a novel microbiaxial optomechanical device that allows two-photon imaging techniques to be coupled with macromechanical stimulation in hydrated planar tissue specimens. This allows that the mechanical response of the microstructure can be quantified and related to the macroscopic response of the same tissue sample. This occurs without the need to fix tissue in strain states that could introduce a change in the microstructural configuration. We demonstrate the passive realignment of fibrous proteins under various types of loading, which demonstrates the ability of tissue microstructure to reinforce itself in periods of high stress. In addition, the collagen and elastin response of tissue during viscoelastic behavior is reported showing interstitial fluid movement and fiber realignment potentially responsible for the temporal behavior. We also demonstrate that nonhomogeneities in fiber strain exist over biaxial regions of assumed homogeneity.

scholarly journals Bright AIE Nanoparticles for Two-Photon Imaging and Localized Compound Therapy of Cancers.pdf

2020 ◽  
Author(s):  
Ying Li ◽  
Rongbing Tang ◽  
Xiaoyan Liu ◽  
Junyi Gong ◽  
Zujin Zhao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Organic Dyes ◽  
Cationic Lipid ◽  
Biological Tissues ◽  
Photon Absorption ◽  
Infrared Light ◽  
Two Photon ◽  
Theranostic Agent ◽  
New Strategy ◽  
Melanoma Model

Photodynamic therapy (PDT) is a non-invasive therapeutic strategy for cancer treatment but it always suffers from low reactive oxygen species (ROS) efficiency generated from traditional organic dyes owing to weak absorption in the optical transparent window of biological tissues and fluorescence quenching at a concentrated solution or in nanoparticles. Herein, we present cationic lipid-encapsulated aggregation-induced emission (AIE) nanoparticles (NPs) that have a high quantum yield (23%) and a maximum two-photon absorption (TPA) cross-section<b><i> </i></b>of 560 GM irradiated by near infrared light (800 nm). The AIE NPs can serve as imaging agents for spatiotemporal imaging of tumor tissues with a penetration depth up to 505 µm on mice melanoma model. Noteworthy, the AIE NPs can efficiently generate singlet oxygen (<sup>1</sup>O<sub>2</sub>) and highly toxic hydroxyl radicals (<b>·</b>OH) upon 800 nm-light irradiation for photodynamic tumor ablation. In addition, the AIE NPs can be effectively cleared from the mouse body after the imaging and therapy. This study provides a new strategy to develop theranostic agent for cancer image-guided PDT with high brightness, superior photostability and high biosafety

scholarly journals Distinct patterns of activity in individual cortical neurons and local networks in primary somatosensory cortex of mice evoked by mechanical limb stimulation

2020 ◽  
Author(s):  
Mischa V. Bandet ◽  
Bin Dong ◽  
Ian R. Winship
Keyword(s):  
Somatosensory Cortex ◽  
Cortical Neurons ◽  
Optical Recording ◽  
Primary Somatosensory Cortex ◽  
Autofluorescence Imaging ◽  
Neuronal Activation ◽  
Local Networks ◽  
Two Photon ◽  
Evoked Activity ◽  
Sensory Evoked

AbstractTo distinguish between somatic stimuli, the primary somatosensory cortex should process dissimilar stimuli with distinct patterns of neuronal activation. Two-photon calcium imaging permits simultaneous optical recording of sensory evoked activity in hundreds of cortical neurons during varied sensory stimulation. Hence, it allows a visualization of patterns of activity in individual neurons and local cortical networks in response to distinct stimulation. Here, flavoprotein autofluorescence imaging was used to map the somatosensory cortex of anaesthetized C57BL/6 mice, and in vivo two-photon Ca2+ imaging was used to define patterns of neuronal activation during mechanical stimulation of the contralateral forelimb or hindlimb at various frequencies (3, 10, 100, 200, and 300 Hz). The data revealed that neurons within the limb associated somatosensory cortex exhibit stimulus-specific patterns of activity. Subsets of neurons were found to have sensory-evoked activity that is either primarily responsive to single stimulus frequencies or broadly responsive to multiple frequencies of limb movement. High frequency stimuli were shown to elicit more activation across the population, with a greater percentage of the population responding and greater percentage of cells with high amplitude responses. Stimulus-evoked cell-cell correlations within these neuronal networks varied as a function of frequency of stimulation, such that each stimulus elicited a distinct pattern that was more consistent across multiple trials of the same stimulus compared to trials at different frequencies of stimulation. The variation in cortical response to these artificial stimuli can thus be represented by the population pattern of supra-threshold Ca2+ transients, the magnitude and temporal properties of the evoked activity, and the structure of the stimulus-evoked correlation between responsive neurons.

scholarly journals Nonlinear optical spectroscopy and two-photon excited fluorescence spectroscopy reveal the excited states of fluorophores embedded in a beetle’s elytra

2018 ◽  
Vol 9 (1) ◽  
pp. 20180052 ◽  
Author(s):  
Sébastien R. Mouchet ◽  
Charlotte Verstraete ◽  
Dimitrije Mara ◽  
Stijn Van Cleuvenbergen ◽  
Ewan D. Finlayson ◽  
...  
Keyword(s):  
Excited States ◽  
Nonlinear Optical ◽  
Polarization State ◽  
Polarized Light ◽  
Fluorescence Emission ◽  
Biological Tissues ◽  
Optical Measurements ◽  
Fluorescence Signal ◽  
Photonic Structure ◽  
Two Photon

Upon illumination by ultraviolet light, many animal species emit light through fluorescence processes arising from fluorophores embedded within their biological tissues. Fluorescence studies in living organisms are however relatively scarce and so far limited to the linear regime. Multiphoton excitation fluorescence analyses as well as nonlinear optical techniques offer unique possibilities to investigate the effects of the local environment on the excited states of fluorophores. Herein, these techniques are applied for the first time to study of the naturally controlled fluorescence in insects. The case of the male Hoplia coerulea beetle is investigated because the scales covering the beetle’s elytra are known to possess an internal photonic structure with embedded fluorophores, which controls both the beetle’s coloration and the fluorescence emission. An intense two-photon excitation fluorescence signal is observed, the intensity of which changes upon contact with water. A third-harmonic generation signal is also detected, the intensity of which depends on the light polarization state. The analysis of these nonlinear optical and fluorescent responses unveils the multi-excited states character of the fluorophore molecules embedded in the beetle’s elytra. The role of form anisotropy in the photonic structure, which causes additional tailoring of the beetle’s optical responses, is demonstrated by circularly polarized light and nonlinear optical measurements.

scholarly journals Estimation of temperature rise at the focus of objective lens at the 1700 nm window

2017 ◽  
Vol 10 (02) ◽  
pp. 1650048 ◽  
Author(s):  
Ping Qiu ◽  
Runfu Liang ◽  
Jiexing He ◽  
Ke Wang
Keyword(s):  
Water Absorption ◽  
Temperature Rise ◽  
Biological Tissues ◽  
Objective Lens ◽  
Experimental Conditions ◽  
Two Photon Microscopy ◽  
Small Water ◽  
Two Photon ◽  
Tissue Scattering ◽  
Order Of Magnitude

Optical microscopy of biological tissues at the 1700[Formula: see text]nm window has enabled deeper penetration, due to the combined advantage of relatively small water absorption and tissue scattering at this wavelength. Compared with excitation at other wavelengths, such as the commonly used 800[Formula: see text]nm window for two-photon microscopy, water absorption at the 1700[Formula: see text]nm window is more than one order of magnitude higher. As a result, more temperature rise can be expected and can be potentially detrimental to biological tissues. Here, we present theoretical estimation of temperature rise at the focus of objective lens at the 1700[Formula: see text]nm window, purely due to water absorption. Our calculated result shows that under realistic experimental conditions, temperature rise due to water absorption is still below 1[Formula: see text]K and may not cause tissue damage during imaging.

scholarly journals Bright AIE Nanoparticles for Two-Photon Imaging and Localized Compound Therapy of Cancers.pdf

2020 ◽  
Author(s):  
Ying Li ◽  
Rongbing Tang ◽  
Xiaoyan Liu ◽  
Junyi Gong ◽  
Zujin Zhao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Organic Dyes ◽  
Cationic Lipid ◽  
Biological Tissues ◽  
Photon Absorption ◽  
Infrared Light ◽  
Two Photon ◽  
Theranostic Agent ◽  
New Strategy ◽  
Melanoma Model

Photodynamic therapy (PDT) is a non-invasive therapeutic strategy for cancer treatment but it always suffers from low reactive oxygen species (ROS) efficiency generated from traditional organic dyes owing to weak absorption in the optical transparent window of biological tissues and fluorescence quenching at a concentrated solution or in nanoparticles. Herein, we present cationic lipid-encapsulated aggregation-induced emission (AIE) nanoparticles (NPs) that have a high quantum yield (23%) and a maximum two-photon absorption (TPA) cross-section<b><i> </i></b>of 560 GM irradiated by near infrared light (800 nm). The AIE NPs can serve as imaging agents for spatiotemporal imaging of tumor tissues with a penetration depth up to 505 µm on mice melanoma model. Noteworthy, the AIE NPs can efficiently generate singlet oxygen (<sup>1</sup>O<sub>2</sub>) and highly toxic hydroxyl radicals (<b>·</b>OH) upon 800 nm-light irradiation for photodynamic tumor ablation. In addition, the AIE NPs can be effectively cleared from the mouse body after the imaging and therapy. This study provides a new strategy to develop theranostic agent for cancer image-guided PDT with high brightness, superior photostability and high biosafety

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