Browsing by Author "Wang, Shang"
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Item Detection and Monitoring of Microparticles Under Skin by Optical Coherence Tomography as an Approach to Continuous Glucose Sensing Using Implanted Retroreflectors(IEEE Sensors Journal, 2015-09) Wang, Shang; Sherlock, Tim; Salazar, Betsy; Sudheendran, Narandran; Manapuram, Ravi K.; Kourentzi, Katerina D.; Ruchhoeft, Paul; Willson, Richard C.; Larin, Kirill V.We demonstrate the feasibility of using optical coherence tomography (OCT) to image and detect 2.8 ?m diameter microparticles (stationary and moving) on a highly-reflective gold surface both in clear media and under skin in vitro. The OCT intensity signal can clearly report the microparticle count, and the OCT response to the number of microparticles shows a good linearity. The detect ability of the intensity change (2.9%�5%) caused by an individual microparticle shows the high sensitivity of monitoring multiple particles using OCT. An optical sensing method based on this feasibility study is described for continuously measuring blood sugar levels in the subcutaneous tissue, and a molecular recognition unit is designed using competitive binding to modulate the number of bound microparticles as a function of glucose concentration. With further development, an ultra-small, implantable sensor might provide high specificity and sensitivity for long-term continuous monitoring of blood glucose concentration.Item Optical Coherence Tomography and Elastography for Tissue Characterization(2014-05) Wang, Shang; Larin, Kirill V.; Akay, Metin; Twa, Michael D.; Larina, Irina V.; Wood, Lowell T.This dissertation reports on the development of low-coherence optical imaging and measurement techniques, focusing on optical coherence elastographic techniques, to meet the growing demand for noninvasive high-resolution tissue characterization with improved diagnosis and treatment of various diseases. The research work is mainly based on optical coherence tomography (OCT), a three-dimensional imaging modality that enables depth-resolved tissue imaging with micro-scale axial resolution. The dissertation work can be summarized in six aspects: 1) the development of an OCT-based computational method utilizing multi-dimensional information on tissue optical properties and structural features for resection margin delineation of soft tissue sarcomas; 2) the development of a combined ultrasound/OCT system and a spectral analyzing method for noninvasive rapid detection of depth-dependent elasticity in transparent samples, as an approach to probe the mechanical property gradient in the crystalline lens of the eye; 3) the development of a combined air-puff/OCT system that can be used for quantitative measurement of tissue elastic properties with the analysis of surface waves for noncontact intraoperative detection of soft-tissue tumors; 4) the development of shear wave imaging OCT (SWI-OCT), a noncontact low-coherence optical phase-based sensing technique that enables depth-resolved ultra-fast visualization of the low-amplitude elastic wave propagation in tissue, which provides direct information on tissue biomechanics, such as the corneal viscoelasticity; 5) the development of quantitative SWI-OCT for noncontact localized measurement of tissue elasticity, which can be used to conduct mechanical assessment of mouse myocardium, providing essential assistance to the studies on cardiac tissue engineering; and 6) the demonstration of an OCT en-face imaging and detection method for the remote monitoring of microparticles on gold surface under skin tissue, based on which an implantable continuous glucose sensing method can be implemented. These techniques and methods are demonstrated with the experiments performed on tissue-mimicking phantoms and biological samples, such as ex vivo human and animal tissues. The results of measurement and detection are verified through the comparisons with gold-standard tests or literature. This dissertation represents the frontier of the emerging research area of optical coherence elastography and is expected to contribute to the field of tissue characterization with both the biological and medical applications.