Non-Destructive Viscoelasticity Microscopy: A Spectroscopic Approach using Dual Brillouin/Raman Scattering Processes
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The tremendous progress in life sciences and medicine has been greatly facilitated by the development of new imaging modalities. The elastic properties of molecules, subcellular and cellular structures play a crucial role in many areas of biology and medicine. Tissue elasticity has recently been recognized as a critical regulator of cell behavior, with clear roles in embryogenesis, tissue morphogenesis and stem cell differentiation, as well as contributing to pathologies such as tumor progression, coronary artery disease and tissue scarring. This dissertation is focused on developing a novel instrumentation to image viscoelastic properties of cells and tissues using Brillouin microspectroscopy. Following design, construction and optimizations that maximize the signal quality, we obtained the highest resolution Brillouin imaging system in a confocal backscattering arrangement suitable for bio-imaging applications. Furthermore, a powerful combination of Brillouin and Raman spectroscopies has yielded a confocal microscope capable of performing simultaneous mechanical and chemical imaging in a non-invasive and noncontact manner. The novel instrument was optimized and validated for several biomedical applications. For example, we demonstrated that Brillouin spectroscopy is capable of performing in-vivo measurements of the mechanical properties of artificial biocompatible materials such as photocrosslinkable gelatin methacrylate (GelMA). With the assistance of animal models of human congenital muscular dystrophies, we show that Brillouin spectroscopy can serve as a unique diagnosis tool, which can detect differences in muscle elasticity even between very similar muscular dystrophy genotypes. We have also demonstrated that Brillouin spectroscopy is an invaluable approach in developmental biology since it is capable of making non-destructive imaging of an embryo's elasticity during its development process, which is crucial to understand the formation of many essential organs such as bone and brain. In summary, we have developed a novel instrument for biomedical imaging sensing, which is compatible with other microscopic imaging modalities and is specific to local elasticity. Numerous applications of this new technology have been explored, and the instrument’s performance was validated for several systems.
Meng, Zhaokai (2016). Non-Destructive Viscoelasticity Microscopy: A Spectroscopic Approach using Dual Brillouin/Raman Scattering Processes. Doctoral dissertation, Texas A & M University. Available electronically from