1. Articles from Richard L. Blackmon

    1-7 of 7
    1. Diffusion tensor optical coherence tomography

      Diffusion tensor optical coherence tomography

      In situ measurements of diffusive particle transport provide insight into tissue architecture, drug delivery, and cellular function. Analogous to diffusion-tensor magnetic resonance imaging (DT-MRI), where the anisotropic diffusion of water molecules is mapped on the millimeter scale to elucidate the fibrous structure of tissue, here we propose diffusion-tensor optical coherence tomography (DT-OCT) for measuring directional diffusivity and flow of optically scattering particles within tissue. Because DT-OCT is sensitive to the sub-resolution motion of Brownian particles as they are constrained by tissue macromolecules, it has the potential to quantify nanoporous anisotropic tissue structure at micrometer resolution as relevant to extracellular matrices ...

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    2. Feature of the Week 05/14/2017: Real-Time Monitoring of Mucus Thinning Treatments using Diffusion-Sensitive Optical Coherence Tomography

      Feature of the Week 05/14/2017: Real-Time Monitoring of Mucus Thinning Treatments using Diffusion-Sensitive Optical Coherence Tomography

      The airway epithelium is coated with a biopolymeric mucus gel which is responsible for trapping inhaled environmental contaminants that are subsequently removed by mucociliary clearance (MCC). MCC is disrupted under high mucus wt%, causing mucus stagnation, chronic infection and inflammation. Normal mucus hydration by the epithelium is impaired in cystic fibrosis (CF) and COPD resulting in high mucus wt% that leads to halted MCC. Hypertonic saline (HS) treatment is a therapeutic approach to reduce mucus wt% for sustained MCC that has gained popularity due to its relative safety, easy administration, and low cost. However, patient to patient variability, conflicting therapeutic ...

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    3. Magnetic and Plasmonic Contrast Agents in Optical Coherence Tomography

      Magnetic and Plasmonic Contrast Agents in Optical Coherence Tomography

      Optical coherence tomography (OCT) has gained widespread application for many biomedical applications, yet the traditional array of contrast agents used in incoherent imaging modalities do not provide contrast in OCT. Owing to the high biocompatibility of iron oxides and noble metals, magnetic and plasmonic nanoparticles, respectively, have been developed as OCT contrast agents to enable a range of biological and pre-clinical studies. Here, we provide a review of these developments within the past decade, including an overview of the physical contrast mechanisms and classes of OCT system hardware add-ons needed for magnetic and plasmonic nanoparticle contrast . A comparison of the ...

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    4. Imaging Extracellular Matrix Remodeling In Vitro by Diffusion-Sensitive Optical Coherence Tomography

      Imaging Extracellular Matrix Remodeling In Vitro by Diffusion-Sensitive Optical Coherence Tomography

      The mammary gland extracellular matrix (ECM) is comprised of biopolymers, primarily collagen I, that are created and maintained by stromal fibroblasts. ECM remodeling by fibroblasts results in changes in ECM fiber spacing (pores) that have been shown to play a critical role in the aggressiveness of breast cancer. However, minimally invasive methods to measure the spatial distribution of ECM pore areas within tissues and in vitro 3D culture models are currently lacking. We introduce diffusion-sensitive optical coherence tomography (DS-OCT) to image the nanoscale porosity of ECM by sensing weakly constrained diffusion of gold nanorods (GNRs). DS-OCT combines the principles of ...

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    5. Diffusion-sensitive optical coherence tomography for real-time monitoring of mucus thinning treatments

      Diffusion-sensitive optical coherence tomography for real-time monitoring of mucus thinning treatments

      Mucus hydration (wt%) has become an increasingly useful metric in real-time assessment of respiratory health in diseases like cystic fibrosis and COPD, with higher wt% indicative of diseased states. However, available in vivo rheological techniques are lacking. Gold nanorods (GNRs) are attractive biological probes whose diffusion through tissue is sensitive to the correlation length of comprising biopolymers. Through employment of dynamic light scattering theory on OCT signals from GNRs, we find that weakly-constrained GNR diffusion predictably decreases with increasing wt% (more disease-like) mucus. Previously, we determined this method is robust against mucus transport on human bronchial epithelial (hBE) air-liquid interface ...

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    6. Probing biological nanotopology via diffusion of weakly constrained plasmonic nanorods with optical coherence tomography

      Probing biological nanotopology via diffusion of weakly constrained plasmonic nanorods with optical coherence tomography

      Biological materials exhibit complex nanotopology , i.e., a composite liquid and solid phase structure that is heterogeneous on the nanoscale. The diffusion of nanoparticles in nanotopological environments can elucidate biophysical changes associated with pathogenesis and disease progression. However, there is a lack of methods that characterize nanoprobe diffusion and translate easily to in vivo studies. Here, we demonstrate a method based on optical coherence tomography (OCT) to depth-resolve diffusion of plasmon-resonant gold nanorods (GNRs) that are weakly constrained by the biological tissue. By using GNRs that are on the size scale of the polymeric mesh, their Brownian motion is minimally ...

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    7. Enhanced thulium fiber laser lithotripsy using micro-pulse train modulation

      Enhanced thulium fiber laser lithotripsy using micro-pulse train modulation

      The thulium fiber laser (TFL) is currently being studied as an alternative to the conventional holmium:YAG (Ho:YAG) laser for lithotripsy. The diode-pumped TFL may be electronically modulated to operate with variable parameters (e.g., pulse rate, pulse duration, and duty cycle) for studying the influence of pulse train mode on stone ablation rates. The TFL under study was operated at 1908 nm, 35-mJ pulse energy, and 500-μs pulse duration, in a train of 5 micro-pulses, with macro-pulse rates of 10 Hz, compared with conventional TFL operation at 10 to 50 Hz. TFL energy was delivered through 100-μm-core fibers ...

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    1-7 of 7
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  2. Topics in the News

    1. (7 articles) University of North Carolina
    2. (7 articles) Richard L. Blackmon
    3. (6 articles) Amy L. Oldenburg
    4. (1 articles) California Institute of Technology
    5. (1 articles) Duke University
    6. (1 articles) Changhuei Yang
    7. (1 articles) Nathaniel M. Fried
    8. (1 articles) Daniel L. Marks
    9. (1 articles) Raghav K. Chhetri
    10. (1 articles) Tufts University
    11. (1 articles) Technical University of Munich
    12. (1 articles) Chinese Academy of Sciences
    13. (1 articles) Pusan National University
    14. (1 articles) Baylor College of Medicine
    15. (1 articles) Jay S. Duker
    16. (1 articles) Michael Joner
    17. (1 articles) Shang Wang
    18. (1 articles) Nadia K. Waheed
    19. (1 articles) Irina V. Larina
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    Enhanced thulium fiber laser lithotripsy using micro-pulse train modulation Probing biological nanotopology via diffusion of weakly constrained plasmonic nanorods with optical coherence tomography Diffusion-sensitive optical coherence tomography for real-time monitoring of mucus thinning treatments Imaging Extracellular Matrix Remodeling In Vitro by Diffusion-Sensitive Optical Coherence Tomography Magnetic and Plasmonic Contrast Agents in Optical Coherence Tomography Feature of the Week 05/14/2017: Real-Time Monitoring of Mucus Thinning Treatments using Diffusion-Sensitive Optical Coherence Tomography Diffusion tensor optical coherence tomography Direct inverse linearization of piezoelectric actuator’s initial loading curve and its applications in full-field optical coherence tomography (FF-OCT) Peripapillary Retinal and Choroidal Perfusion in Nonarteritic Ischemic Optic Neuropathy Using Optical Coherence Tomography Angiography Reliability of foveal avascular zone measurements in eyes with retinal vein occlusion using optical coherence tomography angiography SD-OCT parameters and visual field defect in chiasmal compression and the diagnostic value of neural network model Visualization of deep choroidal vasculatures and measurement of choroidal vascular density: a swept-source optical coherence tomography angiography approach