Electrical & Computer Engineering
Permanent URI for this communityhttp://hdl.handle.net/1903/2234
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Item MONTE CARLO SIMULATIONS OF BRILLOUIN SCATTERING IN TURBID MEDIA(2023) Lashley, Stephanie; Chembo, Yanne K; Electrical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Brillouin microscopy is a non-invasive, label-free optical elastography method for measuring mechanical properties of cells. It provides information on the longitudinal modulus and viscosity of a medium, which can be indicators of traumatic brain injury, cancerous tumors, or fibrosis. All optical techniques face difficulties imaging turbid media, and Monte Carlo simulations are considered the gold-standard to model these scenarios. Brillouin microscopy adds a unique challenge to this problem due to the angular dependence of the scattering event. This thesis extends a traditional Monte Carlo simulation software by adding the capability to simulate Brillouin scattering in turbid media, which provides a method to test strategies to mitigate the effects of multiple elastic scattering without the time and cost associated with physical experiments. Experimental results have shown potential methods to alleviate the problems caused by multiple elastic scattering, and this thesis will verify the simulation results against the experimental findings.Item THREE-DIMENSIONAL BIOPATTERNING TECHNOLOGY AND APPLICATION FOR ENZYME-BASED BIOELECTRONICS(2018) Chu, Sangwook; Ghodssi, Reza; Electrical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Integration of biomaterials with 3-D micro/nano devices and systems offers exciting opportunities for developing miniature bioelectronics with enhanced performances and advanced modes of operation. However, the limited wetting property of such small scale 3-D structures (Cassie-Baxter wetting) presents a potential challenge in these developments considering most biological materials require storage in buffered aqueous solutions due to their inherently narrow stability window. In this thesis research, an electrowetting-assisted 3-D biomanufacturing technology has been developed enabling highly selective and programmable biomolecular assembly on 3-D device components. The successful integration of microscale 3-D device structures created via conventional microfabrication techniques with a nanoscale molecular assembly of Tobacco mosaic virus (TMV), enabled hierarchical and modular material assembly approaches for creating highly functional and scalable enzyme-integrated microsystems components. The potential limitation in 3-D bio-device integration associated with the surface wettability has been investigated by adapting Si-based micropillar arrays (μPAs) as model 3-D device structures, and a cysteine-modified TMV (TMV1cys), as the biomolecular assembler which can functionalize onto electrode surfaces via a self-assembly. The comparative studies using μPAs of varying pillar densities have provided clear experimental evidence that the surface coverage of TMV1cys self-assembly on the μPA is strongly correlated with structural density, indicating the structural hydrophobicity as a key limiting factor for 3-D bio-device integration. The 3-D electro-bioprinting (3D-EBP) technology developed in this work leverages the hydrophobic surface wettability by adapting a capacitive wettability-control technique, known as electrowetting. The biological sample liquid was selectively introduced into the microcavities using a custom-integrated bioprinting system, allowing for patterning of the TMV1cys self-assembly on the μPA substrates without the limitations of the structural density. The functional integrity of the TMV1cys post 3D-EBP allowed conjugations of additional biological molecules within the 3-D substrates. Particularly in this work, immobilization of glucose oxidase (GOx) has been achieved via a hierarchical on-chip immobilization method incorporating 3D-EBP. Combined with the enhanced and scalable enzymatic reaction density on-chip and the electrochemical conversion strategies, the innovative 3D biomanufacturing technology opens up new possibilities for next-generation enzyme-based bioelectronics.Item Optics And Computer Vision For Biomedical Applications(2018) Wang, Bohan; Chen, Yu; Electrical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Bioengineering is at the cross sections of biology, clinical technology, electrical engineering, computer science and many other domains. The smooth translation of domain technologies to clinics is not just about accuracy and practicality of the technology. It also has to take into account the accessibility (cost and portability), the patients’ comfort and the ease to adapt into the workflow of medical professionals. The dissertation will explore three projects, (1) portable and low-cost near infrared florescence imaging system on mobile phone platform, (2) computer aided diagnosis software for diagnosing chronical kidney disease based on optical coherence tomography (OCT) images and (3) the tracking and localization of hand-held medical imaging probe. These projects aim to translate and adapt modern computation hardware, data analysis models and computer vision technologies to solve and refine clinical diagnosis applications. The dissertation will discuss how the translation, tradeoffs and refinement of those technologies can bring a positive impact on the accuracy, ease of conduct, accessibility and patients’ comfort to the clinical applications.