UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

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Author: search.filters.author.Handler, ChenchenSubject: search.filters.subject.Bioengineering

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    MECHANICAL MAPPING OF NEURAL TUBE CLOSURE IN LIVE EMBRYOS USING BRILLOUIN MICROSCOPY
    (2022) Handler, Chenchen; Scarcelli, Giuliano; Bioengineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Neurulation is a process that serves as the precursor to the spinal cord in vertebrates. Neural tube closure (NTC), part of primary neurulation, involves the extensive coordination of cellular, molecular, and mechanical events to transform the flat neural epithelium to a luminated epithelial tube. Neural tube defects (NTD) are the result of mechanical failures that arise during neurulation. Recent research has focused on understanding the molecular mechanisms underlying neurulation but has difficulty correlating them to physical mechanisms. To better understand how physical mechanisms are integrated and responsible for neurulation, several techniques have been applied to study NTC in a range of in vitro environments. However, many of these techniques have been limited due requiring the specimen to be fixed and/ or being invasive and requiring physical contact with the specimen to extract the modulus. As such, there is limited resolution and only the superficial layer of the sample is measured making assessing 2D/3D tissue mechanics inside a growing organism is highly challenging. In this dissertation, we aim to quantify the mechanical state of the neural tube without disruption to development. To do this, we adapted Brillouin microscopy, a non-invasive, label- and contact-free imaging technique, to allows us to probe thelongitudinal modulus of the neural plate at every step of NTC with cellular resolution. This quantification is performed as the embryo develops in real time using time-lapse Brillouin and an improved ex-ovo culture method. We observed an increase in the Brillouin modulus of the neural plate as the embryo develops from Hamburger-Hamilton stage (HH)-6 to HH-12. This increase in modulus is consistent with previous data from other vertebrates such as Xenopus and Mouse embryos and demonstrates the process of neurulation is driven by mechanical forces. Time-lapse Brillouin imaging depicted stiffening and thickening of the neural plate during NTC, suggesting these are coordinated events for NTC. Here, we show that tissue stiffness plays an integral role in NTC and directly quantifying tissue mechanics during neurulation should allow us to better determine the biomechanical nature of NTD.