scholarly journals In vivo imaging of coral tissue and skeleton with optical coherence tomography

2017 ◽  
Vol 14 (128) ◽  
pp. 20161003 ◽  
Author(s):  
Daniel Wangpraseurt ◽  
Camilla Wentzel ◽  
Steven L. Jacques ◽  
Michael Wagner ◽  
Michael Kühl
Keyword(s):  
Optical Coherence Tomography ◽  
Near Infrared ◽  
Fluorescent Protein ◽  
Coral Tissue ◽  
Coral Host ◽  
Live Coral ◽  
Optical Coherence ◽  
Linear Contraction ◽  
Green Fluorescent

Application of optical coherence tomography (OCT) for in vivo imaging of tissue and skeleton structure of intact living corals enabled the non-invasive visualization of coral tissue layers (endoderm versus ectoderm), skeletal cavities and special structures such as mesenterial filaments and mucus release from intact living corals. Coral host chromatophores containing green fluorescent protein-like pigment granules appeared hyper-reflective to near-infrared radiation allowing for excellent optical contrast in OCT and a rapid characterization of chromatophore size, distribution and abundance. In vivo tissue plasticity could be quantified by the linear contraction velocity of coral tissues upon illumination resulting in dynamic changes in the live coral tissue surface area, which varied by a factor of 2 between the contracted and expanded state of a coral. Our study provides a novel view on the in vivo organization of coral tissue and skeleton and highlights the importance of microstructural dynamics for coral ecophysiology.

scholarly journals In vivoimaging of coral tissue and skeleton with optical coherence tomography

2016 ◽  
Author(s):  
Daniel Wangpraseurt ◽  
Camilla Wentzel ◽  
Steven L. Jacques ◽  
Michael Wagner ◽  
Michael Kuhl
Keyword(s):  
Optical Coherence Tomography ◽  
Surface Area ◽  
Fluorescent Protein ◽  
Coral Tissue ◽  
Optical Coherence ◽  
Pocillopora Damicornis ◽  
Dynamic Changes ◽  
Linear Contraction ◽  
Non Invasive

AbstractOptical coherence tomography (OCT) is a non-invasive three-dimensional imaging technique with micrometer resolution allowing microstructural characterization of tissuesin vivoand in real time. We present the first application of OCT forin vivoimaging of tissue and skeleton structure of intact living corals spanning a variety of morphologies and tissue thickness. OCT visualized different coral tissue layers (e.g. endoderm vs ectoderm), special structures such as mesenterial filaments and skeletal cavities, as well as mucus release from living corals. We also developed a new approach for non-invasive imaging and quantification of chromatophores containing green fluorescent protein (GFP)-like host pigment granules in coral tissue. The chromatophore system is hyper-reflective and can thus be imaged with good optical contrast in OCT, enabling quantification of chromatophore size, distribution and abundance. Because of its rapid imaging speed, OCT can also be used to quantify coral tissue movement showing that maximal linear contraction velocity was ~120 μm per second upon high light stimulation. Based on OCT imaging of tissue expansion and contraction, we made first estimates of dynamic changes in the coral tissue surface area, which varied by a factor of 2 between the contracted and expanded state of the coralPocillopora damicornis. We conclude that OCT is an excellent novel tool forin vivotomographic imaging of corals that can reveal tissue and skeleton organization as well as quantify dynamic changes in tissue structure and coral surface area non-invasively and at high spatio-temporal resolution.

scholarly journals Biomolecular Contrast Agents for Optical Coherence Tomography

2019 ◽  
Author(s):  
George J. Lu ◽  
Li-dek Chou ◽  
Dina Malounda ◽  
Amit K. Patel ◽  
Derek S. Welsbie ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Contrast Agents ◽  
Fluorescent Protein ◽  
Mouse Retina ◽  
Optical Coherence ◽  
Gas Vesicles ◽  
Cellular Functions ◽  
Green Fluorescent

ABSTRACTOptical coherence tomography (OCT) has gained wide adoption in biological and medical imaging due to its exceptional tissue penetration, 3D imaging speed and rich contrast. However, OCT plays a relatively small role in molecular and cellular imaging due to the lack of suitable biomolecular contrast agents. In particular, while the green fluorescent protein has provided revolutionary capabilities to fluorescence microscopy by connecting it to cellular functions such as gene expression, no equivalent reporter gene is currently available for OCT. Here we introduce gas vesicles, a unique class of naturally evolved gas-filled protein nanostructures, as the first genetically encodable OCT contrast agents. The differential refractive index of their gas compartments relative to surrounding aqueous tissue and their nanoscale motion enables gas vesicles to be detected by static and dynamic OCT at picomolar concentrations. Furthermore, the OCT contrast of gas vesicles can be selectively erasedin situwith ultrasound, allowing unambiguous assignment of their location. In addition, gas vesicle clustering modulates their temporal signal, enabling the design of dynamic biosensors. We demonstrate the use of gas vesicles as reporter genes in bacterial colonies and as purified contrast agentsin vivoin the mouse retina. Our results expand the utility of OCT as a unique photonic modality to image a wider variety of cellular and molecular processes.

Gold Nanobipyramids as Second Near Infrared Optical Coherence Tomography Contrast Agents for in Vivo Multiplexing Studies

Nano Letters ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Peng Si ◽  
Saba Shevidi ◽  
Edwin Yuan ◽  
Ke Yuan ◽  
Ziv Lautman ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Contrast Agents ◽  
Near Infrared ◽  
Optical Coherence ◽  
Gold Nanobipyramids

scholarly journals Measuring light scattering and absorption in corals with Inverse Spectroscopic Optical Coherence Tomography (ISOCT): a new tool for non-invasive monitoring

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
G. L. C. Spicer ◽  
A. Eid ◽  
D. Wangpraseurt ◽  
T. D. Swain ◽  
J. A. Winkelmann ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Properties ◽  
Light Scattering ◽  
Light Propagation ◽  
Coral Tissue ◽  
Coral Host ◽  
Invasive Monitoring ◽  
Optical Coherence ◽  
Invasive Approach ◽  
Non Invasive

Abstract The success of reef-building corals for >200 million years has been dependent on the mutualistic interaction between the coral host and its photosynthetic endosymbiont dinoflagellates (family Symbiodiniaceae) that supply the coral host with nutrients and energy for growth and calcification. While multiple light scattering in coral tissue and skeleton significantly enhance the light microenvironment for Symbiodiniaceae, the mechanisms of light propagation in tissue and skeleton remain largely unknown due to a lack of technologies to measure the intrinsic optical properties of both compartments in live corals. Here we introduce ISOCT (inverse spectroscopic optical coherence tomography), a non-invasive approach to measure optical properties and three-dimensional morphology of living corals at micron- and nano-length scales, respectively, which are involved in the control of light propagation. ISOCT enables measurements of optical properties in the visible range and thus allows for characterization of the density of light harvesting pigments in coral. We used ISOCT to characterize the optical scattering coefficient (μs) of the coral skeleton and chlorophyll a concentration of live coral tissue. ISOCT further characterized the overall micro- and nano-morphology of live tissue by measuring differences in the sub-micron spatial mass density distribution (D) that vary throughout the tissue and skeleton and give rise to light scattering, and this enabled estimates of the spatial directionality of light scattering, i.e., the anisotropy coefficient, g. Thus, ISOCT enables imaging of coral nanoscale structures and allows for quantifying light scattering and pigment absorption in live corals. ISOCT could thus be developed into an important tool for rapid, non-invasive monitoring of coral health, growth and photophysiology with unprecedented spatial resolution.

scholarly journals Optical Coherence Tomography for Three-Dimensional Imaging in the Biomedical Field: A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Shu Zheng ◽  
Yanru Bai ◽  
Zihao Xu ◽  
Pengfei Liu ◽  
Guangjian Ni
Keyword(s):  
Optical Coherence Tomography ◽  
High Speed ◽  
Near Infrared ◽  
Polarization State ◽  
Three Dimensional ◽  
Biological Research ◽  
Light Sources ◽  
Optical Coherence ◽  
Biomedical Field

Optical coherence tomography (OCT) has become a novel approach to noninvasive imaging in the past three decades, bringing a significant potential to biological research and medical biopsy in situ, particularly in three-dimensional (3D) in vivo conditions. Specifically, OCT systems using broad bandwidth sources, mainly centered at near-infrared-II, allow significantly higher imaging depth, as well as maintain a high-resolution and better signal-to-noise ratio than the traditional microscope, which avoids the scattering blur and thus obtains more details from delicate biological structures not just limited to the surface. Furthermore, OCT systems combined the spectrometer with novel light sources, such as multiplexed superluminescent diodes or ultra-broadband supercontinuum laser sources, to obtain sub-micron resolution imaging with high-speed achieve widespread clinical applications. Besides improving OCT performance, the functional extensions of OCT with other designs and instrumentations, taking polarization state or birefringence into account, have further improved OCT properties and functions. We summarized the conventional principle of OCT systems, including time-domain OCT, Fourier-domain OCT, and several typical OCT extensions, compared their different components and properties, and analyzed factors that affect OCT performance. We also reviewed current applications of OCT in the biomedical field, especially in hearing science, discussed existing limitations and challenges, and looked forward to future development, which may provide a guideline for those with 3D in vivo imaging desires.

scholarly journals Decorrelation Time Analysis Using Dynamic Light Scattering with Optical Coherence Tomography in an in vivo Mouse Tumour Model

2021 ◽  
Author(s):  
Timothy Wan Hei Luk
Keyword(s):  
Optical Coherence Tomography ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Near Infrared ◽  
Imaging Modality ◽  
Preclinical Study ◽  
Infrared Light ◽  
Target Tissue ◽  
Optical Coherence

Optical coherence tomography (OCT) is an imaging modality that uses near infrared light interferometry for non-invasive, near-histological resolution imaging at the micron level. Concepts from dynamic light scattering (DLS) can be adapted to OCT to detect and measure the motions in the target tissue. Tissue dynamics can be observed by measuring the speckle decorrelation time (DT) of the tissue. DT analysis was performed in a preclinical study to demonstrate the repeatability and feasibility of using DLS-OCT to observe mouse tumours undergoing cisplatin treatment over a 48-hour period. Differences in the average DT data were observed for control and cisplatin-injected mice. Image segmentation based on DT values was also performed to subtract the DT contributions of pixels at blood vessel locations, resulting in the improvement of average DT calculations of the tumour tissue. The results presented are a preliminary step to analyzing and monitoring tumour growth and treatment response in vivo.

scholarly journals Green fluorescent protein-like pigments optimize the internal light environment in symbiotic reef building corals

2021 ◽  
Author(s):  
Elena Bollati ◽  
Niclas H. Lyndby ◽  
Cecilia D’Angelo ◽  
Michael Kühl ◽  
Jörg Wiedenmann ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Shallow Water ◽  
Fluorescent Protein ◽  
Red Light ◽  
Fluorescence Emission ◽  
Fine Tuning ◽  
Light Environment ◽  
Coral Tissue ◽  
Green Fluorescent

AbstractPigments homologous to the Green Fluorescent Protein (GFP) have been proposed to fine-tune the internal light microclimate of corals, facilitating photoacclimation of photosynthetic coral symbionts (Symbiodiniaceae) to life in different reef habitats and environmental conditions. However, direct measurements of the in vivo light conditions inside the coral tissue supporting this conclusion are lacking. Here, we quantified the intra-tissue spectral light environment of corals expressing GFP-like proteins from widely different light regimes. We focus on (1) photoconvertible red fluorescent proteins (pcRFPs), thought to enhance photosynthesis in mesophotic habitats via wavelength conversion, and (2) chromoproteins (CPs), which provide photoprotection to the symbionts in shallow water via light absorption. Optical microsensor measurements indicated that both pigment groups strongly alter the coral tissue light environment. Estimates derived from light spectra measured in pcRFP-containing corals showed that fluorescence emission can contribute to >50% of orange-red light available to the photosynthetic symbionts at mesophotic depths. We further show that upregulation of pink CPs in shallow-water corals during bleaching leads to a reduction of orange light by 10-20% compared to low-CP tissue. Thus, screening by CPs has an important role in mitigating the light-enhancing effect of coral tissue scattering during bleaching. Our results provide the first experimental quantification of the importance of GFP-like proteins in fine-tuning the light microclimate of corals during photoacclimation.

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