1. Articles from Benedikt W. Graf

    1-14 of 14
    1. High Resolution Phase-Sensitive Magnetomotive Optical Coherence Microscopy for Tracking Magnetic Microbeads and Cellular Mechanics

      High Resolution Phase-Sensitive Magnetomotive Optical Coherence Microscopy for Tracking Magnetic Microbeads and Cellular Mechanics

      We present a real-time multimodal near-infrared imaging technology that tracks externally-induced axial motion of magnetic microbeads in single cells in culture. The integrated multimodal imaging technique consists of phase-sensitive magnetomotive optical coherence microscopy (MM-OCM) and multiphoton microscopy (MPM). MPM is utilized for the visualization of multifunctional fluorescent and magnetic microbeads, while MM-OCM detects, with nanometer-scale sensitivity, periodic displacements of the microbeads induced by the modulation of an external magnetic field. Magnetomotive signals are measured from mouse macrophages, human breast primary ductal carcinoma cells, and human breast epithelial cells in culture, and validated with full-field phase-sensitive microscopy. This methodology demonstrates the ...

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    2. Long-term time-lapse multimodal intravital imaging of regeneration and bone-marrow-derived cell dynamics in skin (World Scientific)

      Long-term time-lapse multimodal intravital imaging of regeneration and bone-marrow-derived cell dynamics in skin (World Scientific)

      A major challenge for translating cell-based therapies is understanding the dynamics of cells and cell populations in complex in vivo environments. Intravital microscopy has shown great promise for directly visualizing cell behavior in vivo. However, current methods are limited to relatively short imaging times (hours), by ways to track cell and cell population dynamics over extended time-lapse periods (days to weeks to months), and by relatively few imaging contrast mechanisms that persist over extended investigations. We present technology to visualize and quantify complex, multifaceted dynamic changes in natural deformable skin over long time periods using novel multimodal imaging and a ...

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    3. Imaging and tracking of bone marrow-derived immune and stem cells

      Imaging and tracking of bone marrow-derived immune and stem cells

      Bone marrow (BM)-derived stem and immune cells play critical roles in maintaining the health, regeneration, and repair of many tissues. Given their important functions in tissue regeneration and therapy, tracking the dynamic behaviors of BM-derived cells has been a long-standing research goal of both biologists and engineers. Because of the complex cellular-level processes involved, real-time imaging technologies that have sufficient spatial and temporal resolution to visualize them are needed. In addition, in order to track cellular dynamics, special attention is needed to account for changes in the microenvironment where the cells reside, for example, tissue contraction, stretching, development, etc ...

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    4. Feature Of The Week 12/9/12: University of Illinois at Urbana Champaign Researchers Extend Astronomical Guide-Star Techniques to Computational OCT Imaging

      Feature Of The Week 12/9/12: University of Illinois at Urbana Champaign Researchers Extend Astronomical Guide-Star Techniques to Computational OCT Imaging

      Researchers at the University of Illinois at Urbana-Champaign have a long history of novel work in the field of OCT and related fields.  This includes the very promising area of computational adaptive optics and related methods that offer the promise of dramatically improved images in a wide variety of settings by performing post-acquisition processing of magnitude and phase data.  Below is a summary of some of their recent work.  Aberrations degrade resolution, contrast, and signal-to-noise ratio in optical microscopy. In optical coherence tomography (OCT), aberrations limit the resolution of diagnostic features, notably in retinal OCT. With optical coherence microscopy, which ...

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    5. Guide-star-based computational adaptive optics for broadband interferometric tomography

      Guide-star-based computational adaptive optics for broadband interferometric tomography

      We present a method for the numerical correction of optical aberrations based on indirect sensing of the scattered wavefront from point-like scatterers (“guide stars”) within a three-dimensional broadband interferometric tomogram. This method enables the correction of high-order monochromatic and chromatic aberrations utilizing guide stars that are revealed after numerical compensation of defocus and low-order aberrations of the optical system. Guide-star-based aberration correction in a silicone phantom with sparse sub-resolution-sized scatterers demonstrates improvement of resolution and signal-to-noise ratio over a large isotome. Results in highly scattering muscle tissue showed improved resolution of fine structure over an extended volume. Guide-star-based computational adaptive ...

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    6. Feature Of The Week 6/10/12: Computational Adaptive Optics: A New Digital Post-Processing Technique to Optimize Resolution in OCT and other Interferometric Optical Imaging Applications

      Feature Of The Week 6/10/12: Computational Adaptive Optics: A New Digital Post-Processing Technique to Optimize Resolution in OCT and other Interferometric Optical Imaging Applications

      OCT and other interferometric optical 2D and 3D imaging techniques have long been plagued by the fundamental optical limitations such as that which occurs between depth-of-field (Rayleigh range) and lateral resolution or limitations in image resolution due to optical aberrations (spatial and spectral) that occur within delivery or collection optics or within tissue themselves.  Over the past few years there have been a variety of new powerful post optical detection signal processing techniques that promise to shatter these traditional limitations and take OCT and other interferometric optical imaging techniques to a new level.  These techniques are all related on some ...

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    7. Computational adaptive optics for broadband optical interferometric tomography of biological tissue

      Computational adaptive optics for broadband optical interferometric tomography of biological tissue

      Aberrations in optical microscopy reduce image resolution and contrast, and can limit imaging depth when focusing into biological samples. Static correction of aberrations may be achieved through appropriate lens design, but this approach does not offer the flexibility of simultaneously correcting aberrations for all imaging depths, nor the adaptability to correct for sample-specific aberrations for high-quality tomographic optical imaging. Incorporation of adaptive optics (AO) methods have demonstrated considerable improvement in optical image contrast and resolution in noninterferometric microscopy techniques, as well as in optical coherence tomography. Here we present a method to correct aberrations in a tomogram rather than the ...

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    8. Integrated multimodal optical microscopy for structural and functional imaging of engineered and natural skin

      Integrated multimodal optical microscopy for structural and functional imaging of engineered and natural skin

      An integrated multimodal optical microscope is demonstrated for high-resolution, structural and functional imaging of engineered and natural skin. This microscope incorporates multiple imaging modalities including optical coherence (OCM), multi-photon (MPM), and fluorescence lifetime imaging microscopy (FLIM), enabling simultaneous visualization of multiple contrast sources and mechanisms from cells and tissues. Spatially co-registered OCM/MPM/FLIM images of multi-layered skin tissues are obtained, which are formed based on complementary information provided by different modalities, i.e., scattering information from OCM, molecular information from MPM, and functional cellular metabolism states from FLIM. Cellular structures in both the dermis and epidermis, especially different morphological ...

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    9. Multimodal in vivo skin imaging with integrated optical coherence and multiphoton microscopy

      Multimodal in vivo skin imaging with integrated optical coherence and multiphoton microscopy
      In this paper we demonstrate high resolution, multimodal in vivo imaging of human skin using optical coherence (OCM) and multiphoton microscopy (MPM). These two modalities are integrated into a single instrument to enable simultaneous acquisition and co-registration. The system design and the OCM image processing architecture enable sufficient performance of both modalities for in vivo imaging of human skin. Examples of multimodal in vivo imaging are presented as well as time lapse imaging of blood flow in single capillaries. By making use of multiple intrinsic contrast mechanisms this integrated technique improves the ability to non-invasively visualize living tissue. Integrated OCM ...
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    10. The impact of aberrations on object reconstruction with interferometric synthetic aperture microscopy

      The impact of aberrations on object reconstruction with interferometric synthetic aperture microscopy

      Interferometric synthetic aperture microscopy (ISAM) reconstructs the scattering potential of a sample with spatially invariant resolution, based on the incident beam profile, the beam scan pattern, the physical model of light sample interaction, and subsequent light collection by the system. In practice, aberrations may influence the beam profile, particularly at higher NA, when ISAM is expected to provide maximum benefit over optical coherence microscopy. Thus it is of interest to determine the effects of aberrations on ISAM reconstructions. In this paper we present the forward model incorporating the effects of aberrations, which forms the basis for aberration correction in ISAM ...

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    11. Correction of coherence gate curvature in high numerical aperture optical coherence imaging

      Correction of coherence gate curvature in high numerical aperture optical coherence imaging
      We present a method for correcting coherence gate curvature caused by scanning-induced path length variations in spectral-domain high-NA optical coherence imaging systems. These variations cause curvature artifacts in optical coherence tomography and effectively restrict the field of view in optical coherence microscopy (OCM). Here we show that the coherence gate curvature can be measured and corrected by recovering the phase of the analytic signal from a calibration image. This phase information can be used directly to process OCM images allowing the coherence gate curvature, as well as any order of system dispersion, to be corrected in a computationally efficient manner ...
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    12. Imaging and Analysis of Three-Dimensional Cell Culture Models

      Imaging and Analysis of Three-Dimensional Cell Culture Models
      Three-dimensional (3D) cell cultures are important tools in cell biology research and tissue engineering because they more closely resemble the architectural microenvironment of natural tissue, compared to standard two-dimensional cultures. Microscopy techniques that function well for thin, optically transparent cultures, however, are poorly suited for imaging 3D cell cultures. Three-dimensional cultures may be thick and highly scattering, preventing light from penetrating without significant distortion. Techniques that can image thicker biological specimens at high resolution include confocal microscopy, multiphoton microscopy, and optical coherence tomography. In this chapter, these three imaging modalities are described and demonstrated in the assessment of functional and ...
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    13. Imaging engineered tissues using structural and functional optical coherence tomography

      As the field of tissue engineering evolves, there will be an increasingly important need to visualize and track the complex dynamic changes that occur within three-dimensional constructs. Optical coherence tomography (OCT), as an emerging imaging technology applied to biological materials, offers a number of significant advantages to visualize these changes. Structural OCT has been used to investigate the longitudinal development of engineered tissues and cell dynamics such as migration, proliferation, detachment, and cell-material interactions. Optical techniques that image functional parameters or integrate multiple imaging modalities to provide complementary contrast mechanisms have been developed, such as the integration of optical coherence ...
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    14. Detecting intrinsic scattering changes correlated to neuron action potentials using optical coherence imaging

      Detecting intrinsic scattering changes correlated to neuron action potentials using optical coherence imaging
      We demonstrate how optical coherence imaging techniques can detect intrinsic scattering changes that occur during action potentials in single neurons. Using optical coherence tomography (OCT), an increase in scattering intensity from neurons in the abdominal ganglion of Aplysia californica is observed following electrical stimulation of the connective nerve. In addition, optical coherence microscopy (OCM), with its superior transverse spatial resolution, is used to demonstrate a direct correlation between scattering intensity changes and membrane voltage in single cultured Aplysia bag cell neurons during evoked action potentials. While intrinsic scattering changes are small, OCT and OCM have potential use as tools in ...
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    1-14 of 14
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  2. Topics in the News

    1. (14 articles) University of Illinois at Urbana-Champaign
    2. (14 articles) Stephen A. Boppart
    3. (7 articles) Steven G. Adie
    4. (5 articles) P. Scott Carney
    5. (5 articles) Adeel Ahmad
    6. (2 articles) Eric J. Chaney
    7. (2 articles) Youbo Zhao
    8. (2 articles) Nathan D. Shemonski
    9. (1 articles) Tyler S. Ralston
    10. (1 articles) Xing Liang
    11. (1 articles) Sungkyunkwan University
    12. (1 articles) Texas A&M University
    13. (1 articles) FDA
    14. (1 articles) University of Southern California
    15. (1 articles) Joon Mo Kim
    16. (1 articles) Brian E. Applegate
    17. (1 articles) Wihan Kim
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    Imaging and Analysis of Three-Dimensional Cell Culture Models Correction of coherence gate curvature in high numerical aperture optical coherence imaging The impact of aberrations on object reconstruction with interferometric synthetic aperture microscopy Multimodal in vivo skin imaging with integrated optical coherence and multiphoton microscopy Computational adaptive optics for broadband optical interferometric tomography of biological tissue Feature Of The Week 6/10/12: Computational Adaptive Optics: A New Digital Post-Processing Technique to Optimize Resolution in OCT and other Interferometric Optical Imaging Applications Guide-star-based computational adaptive optics for broadband interferometric tomography Feature Of The Week 12/9/12: University of Illinois at Urbana Champaign Researchers Extend Astronomical Guide-Star Techniques to Computational OCT Imaging Long-term time-lapse multimodal intravital imaging of regeneration and bone-marrow-derived cell dynamics in skin (World Scientific) High Resolution Phase-Sensitive Magnetomotive Optical Coherence Microscopy for Tracking Magnetic Microbeads and Cellular Mechanics Medical treatment of inflammatory punctual stenosis monitored by anterior segment optical coherence tomography Development and Validation of a Deep Learning System for Diagnosing Glaucoma Using Optical Coherence Tomography