Engineering Commons^™

Shape Memory Alloy Capsule Micropump For Drug Delivery Applications, Youssef Mohamed Kotb

Theses and Dissertations

Implantable drug delivery devices have many benefits over traditional drug administration techniques and have attracted a lot of attention in recent years. By delivering the medication directly to the tissue, they enable the use of larger localized concentrations, enhancing the efficacy of the treatment. Passive-release drug delivery systems, one of the various ways to provide medication, are great inventions. However, they cannot dispense the medication on demand since they are nonprogrammable. Therefore, active actuators are more advantageous in delivery applications. Smart material actuators, however, have greatly increased in popularity for manufacturing wearable and implantable micropumps due to their high energy …

Colloid Fabrication For Biomedical Engineering Applications Through Droplet Microfluidics, Lewis I. Larsen

Biomedical Engineering ETDs

The goal of this work was to leverage soft colloid fabrication through droplet microfluidics to improve the biomedical fields of radiotracer microspheres for selective internal radiation therapy (SIRT) and 3D hydrogel tissue constructs for cell culture with future potential as a platform to study liver diseases and drug response. The importance of positron emission tomography (PET) imaging microspheres infused with positron-emitting radioisotopes such as Ga-68, Cu-64, and F-18 is that they accurately map tumor-to-liver uptake (TLR) ratio and lung shunting factor of hepatocellular carcinoma. These pretreatment radiotracers model the intravascular accumulation behavior of radioactive therapeutic Y-90 SIRT microspheres. Qualifying patients, …

Enhanced Fabrication Of Microdroplet Generator Nozzle Arrays: Optimizing Koh Etching For Microfluidic Applications, Hongyu Bai

McKelvey School of Engineering Theses & Dissertations

Ultrasonic microdroplet generators are useful devices with broad applications ranging from aerosolized drug delivery to three-dimensional (3D) printing-based additive manufacturing. One such technology comprises a microfabricated array of nozzles with droplet production driven by a piezoelectric transducer. The present study focuses on refining a critical fabrication step, anisotropic wet etching of pyramidal nozzles using a basic potassium hydroxide (KOH) solution. Given the integral role of nozzle geometry in device operation, high-precision techniques including Reactive Ion Etching (RIE), Deep Reactive Ion Etching (DRIE), and KOH wet etching were employed. A tapering geometry is preferred for acoustic wave focusing and efficient droplet …

Metal Additive Microfabrication Of Semiconductor Packages With Inbuilt Thermal Management System, Bhushan Lohani

Open Access Theses & Dissertations

Moore’s law describes the development capabilities in electronics manufacturing. Although his estimation held for decades, at present, the doubling of components every two years seems to be approaching a halt. The assessment was based on the miniaturization of transistors to create space for more. Miniaturization led to higher component density, decreased cost, lowered power consumption, and compactness. However, it also came with high current density, increased Joule heating, and reduced critical charge. One of the limiting factors is the heat generated from such devices, which is heavily discussed in International Roadmap for Devices and Systems (IRDS) and International Technology Roadmap …

Extensional Flows Of Polymer Solutions In Planar Microchannels, Mahmud Kamal Raihan

All Dissertations

Non-Newtonian fluids such as polymer solutions often flow under microscale extensional conditions in many natural and engineering flow fields such as in microfluidic chips, porous rocks, biological membranes and filters, printheads in additive manufacturing, etc. The changing cross sectional areas of the internal flow passages therein exert additional extension on the flow along with the shearing. Numerous studies have been dedicated to understanding the extensional flows of polymer solutions over the years. However, most of these studies only focused on flexible polymers exhibiting elasticity in their macroscopic rheology, whereas rigid polymers that portray shear-thinning but often elude elasticity in the …

Development And Application Of A Microfluidic Platform For Quantifying Intra-Tumoral Compressive Stress., Zachary P. Fowler

Electronic Theses and Dissertations

Cancer progression is linked to the emergence of aberrant mechanical signaling in the tumor microenvironment. Modulation of extrinsic signals, such as ECM stiffness and composition, have been thoroughly explored. However, the development of solid stresses within the tumor remains poorly understood. To address this, we have developed a microfluidic platform that generates deformable alginate microbeads that allow for the quantification of compressive stresses generated within a growing glioblastoma (GBM) tumorsphere. PDMS microfluidic devices were fabricated via SU-8 mold with channels ranging from 10µm-40µm in diameter. Fluorescently labeled sodium alginate underwent a cross-linking reaction within the device to generate monodisperse beads …

Novel Microfluidic Devices To Model The Interactions Between Lymphatics And Breast Cancer, Jade Weber

McKelvey School of Engineering Theses & Dissertations

The lymphatic system is responsible for immune circulation and fluid balance in the body. It accomplishes this by draining interstitial fluid from local tissue and transferring it to lymph nodes and back into blood circulation. However, this process is implicated in many pathologies, one of the most dangerous being breast cancer metastasis to the lymph nodes. The largest factor in breast cancer patient mortality is metastasis. Lymphangiogenesis, the growth of new lymphatic vessels, has been thought to play a dynamic role in aiding breast cancer metastasis. Breast cancer tumor cells have been shown to remodel the functionality of local lymph …

The Development Of A Primer Payload With Microparticles For Uti Pathogen Identification Using Polythymidine- Modified Lamp Primers In Droplet Lamp, Jonas Otoo

KGI Theses and Dissertations

Nucleic acid amplification tests (NAATs) are among the diagnostic tests with the highest sensitivity and specificity. However, they are more complex to develop than other diagnostic tests such as biochemical tests and lateral flow immunoassay tests. Polymerase chain reaction (PCR) is the gold standard for NAATs. PCR requires thermal cycling to achieve clonal amplification of the target pathogen DNA for diagnosis. Thermal cycling poses a challenge in the development of PCR diagnostics for point-of-care (POC) settings. Loop-mediated isothermal amplification (LAMP) offers an isothermal method for NAATs diagnostics. The advancement of the microfluidics field significantly enhances the development of LAMP diagnostics …

Low-Cost Microstereolithography 3d Printing With Microfluidic Microsampling Applications, Lauren Twombly

Chemistry & Biochemistry Undergraduate Honors Theses

The growing field of stereolithography 3D printing has welcomed a new age ofmicrofluidic device fabrication techniques. When compared to previous planar fabrication techniques such as soft-lithography, stereolithography 3D printing offers highly automated procedures, reduced fabrication times, and greater complexity of device features. To date, the greatest tradeoff for 3D printing in microfluidic device fabrication is poorer resolution when compared to soft-lithography which can produce feature sizes on the nanometer scale. The poorer resolution of 3D printing limits the feasible size of features. While highly sophisticated 3D printers are capable of achieving sub 10 μm resolution, these instruments are incredibly expensive …

Utilizing Fluorescent Nanoscale Particles To Create A Map Of The Electric Double Layer, Quintus Owen

Theses and Dissertations

The interactions between charged particles in solution and an applied electric field follow several models, most notably the Gouy-Chapman-Stern model, for the establishment of an electric double layer along the electrode, but these models make several assumptions of ionic concentrations and an infinite bulk solution. As more scientific progress is made for the finite and single molecule reactions inside microfluidic cells, the limitations of the models become more extreme. Thus, creating an accurate map of the precise response of charged nanoparticles in an electric field becomes increasingly vital. Another compounding factor is Brownian motion’s inverse relationship with size: large easily …

A 3d Bioprinted Hydrogel Microfluidic Device For Screening Applications, Anant Bhusal

Theses and Dissertations

The microfluidic enabled the integration of engineered miniaturized tissue models for drug screening. Conventional polydimethylsiloxane or plastic-based devices require multiple fabrication steps, which are challenging. We developed a 3D bioprinting approach to create prototypes of hydrogel-based multi-material microfluidic devices integrated with microtissue models. The approach utilizes poly(ethylene glycol) diacrylate and gelatin-methacryloyl to create microfluidic chips using multi-material bioprinting capacity with a high resolution of 15µm on x-y and 50µm on the z-axis and post-printing viability of >90%. We demonstrated easy regulation of stiffness from 24±5 kPa to 1,180±9 kPa and burst pressure from 16±1kPa to 256±19 kPa in the chip …

Pneumatic Latched Demultiplexer Circuit For Controlling Multi-Actuator Soft Robots, Arsh Noor Amin

Master’s Theses

This thesis presents a novel method for controlling multi-actuator soft robots using pneumatic latched demultiplexer circuits implemented with monolithic membrane valves. The pneumatic circuits are designed to address the problems of heavy dependence on hard electrical components and lack of feasible multi-actuator soft robotic systems that limit the potential applications of soft robotics. The proposed pneumatic demultiplexers reduce the number of solenoid valves and electrical components required to drive soft robotic systems, making soft robot control mechanisms more compliant, scalable, and versatile. The thesis demonstrates the design, fabrication, and testing of 4-bit and n-bit pneumatic demultiplexer circuits that can control …

Development Of A 3d-Printed Microfluidic Droplet-On-Demand System For The Deterministic Encapsulation And Processing Of Biological Materials, Chandler A. Warr

Theses and Dissertations

The growing threat of antimicrobial resistance is among the largest concerns in the world today. One method under development to combat this issue is the encapsulation of microbes in microfluidic droplets for single-cell testing. This method may be able to circumvent the need for a traditional positive cell culture which consumes the majority of the testing time using current diagnostic methods. This dissertation presents a method by which to deterministically encapsulate microbes using an artificial intelligence object detection algorithm and a Droplet-On-Demand microfluidic device. To accomplish this, the Droplet-On-Demand microfluidic device was first developed using a unique 3D-printing manufacturing method. …

Developing Ultra-High Resolution 3d Printing For Microfluidics, Kent Richard Hooper

Theses and Dissertations

Building upon previous research on Digital Light Projection (DLP) 3D printing for microfluidics, in this thesis I performed the detailed design and fabrication of a novel DLP 3D printer to increase resolution and device footprint flexibility. This new printer has a pixel resolution twice that of our group’s previous printers (3.8 μm vs 7.6 μm). I demonstrated a new state of the art for minimum channel width, reducing the minimum width to 15 μm wide (and 30 μm tall). This is an improvement over the previous smallest width of 20 μm. This printer also has the capacity to perform multiple …

A Rapid And Ultra-Sensitive Biosensing Platform Based On Tunable Dielectrophoresis For Robust Poc Applications, Yu Jiang

Doctoral Dissertations

With the ongoing pandemic, there have been increasing concerns recently regarding major public health issues such as abuse of organophosphorus compounds, pathogenic bacterial infections, and biosecurity in agricultural production. Biosensors have long been considered a kernel technology for next-generation diagnostic solutions to improve food safety and public health. Significant amounts of effort have been devoted to inventing novel sensing mechanisms, modifying their designs, improving their performance, and extending their application scopes. However, the reliability and selectivity of most biosensors still have much to be desired, which holds back the development and commercialization of biosensors, especially for on-site and point-of-care (POC) …

Optofluidic Manipulation With Nanomembrane Platforms Used For Solid-State Nanopore Integration, Zachary J. Walker

Theses and Dissertations

Nanopore technology has introduced new techniques for single particle detection and analysis. A nanopore consists of a small opening in a membrane on the nanometer scale. Nanopores are found in nature and are utilized for transporting molecules through biological membranes. Researchers have been able to mimic naturally forming biological nanopores and utilize them for a variety of sensing applications. Nanopores, fabricated either organically or inorganically, can be used for detecting biomarkers such as proteins, nucleic acids, and metabolites that translocate the membrane by way of the nanopore. Constant ionic current flow is measured through the nanopore by way of a …

A New Approach For 3d Printed Microfluidic Device Design Based On Pre-Defined Components, Cassandra Ester Slaugh

Theses and Dissertations

3D printing for microfluidic device fabrication has received considerable interest in recent years, in part driven by the potential to dramatically speed up device development by reducing device fabrication time to the minutes timescale. Moreover, in contrast to traditional cleanroom-based fabrication processes that require manual production and stacking of a limited number of layers, 3D printing allows full use of the 3D fabrication volume to lay out microfluidic elements with complex yet compact 3D geometries. The Nordin group has successfully developed multiple generations of high resolution printers and materials for microfluidic devices that achieve this vision. However, because of the …

Synthesis Of Thiol-Acrylate Hydrogels For 3d Cell Culture And Microfluidic Applications, Anowar Hossain Khan

LSU Doctoral Dissertations

Globally cell culture is an $18.98 billion industry as of 2020, with an 11.6 percent annual growth rate. Drug discovery has an estimated worth of $69.8 billion in 2020 and is predicted to grow to $110.4 billion by 2025. Three-dimensional (3D) cell culture of cancer cells is one of the rapidly growing felids since it better recapitulates in vivo conditions compared to two-dimensional (2D) models. However, it is challenging to grow 3D tumor spheroids outside the body, and some of the existing technology can generate these spheroids outside the human body but poorly mimic in vivo tumor models. Therefore, there …

Verification Of A Digital Microfluidics Platform, Karanpartap Singh

Electrical Engineering

The electrowetting effect describes the change in contact angle between a solid surface and electrolyte in response to an applied electric potential difference. Given a planar array of individually-actuated electrodes, electrowetting can be used to transport, mix, and separate picoliter to microliter-sized droplets of liquid on a dielectric layer. Applications of this phenomenon range from lab-on-a-chip and other microfluidic devices to liquid lenses capable of altering their topology and focus within milliseconds.

This project extends prior work simulating the dependence of droplet velocity on actuation voltage and demonstrates observed physics on a physical platform. The simulation portion of this project …

An Electrochemical, Fluidic, Chip-Based Biosensor For Biomarker Detection, Lauren Bell

Theses and Dissertations--Biomedical Engineering

Biosensors and their use in both the research and clinical field for the detection and monitoring of critical biomarkers are prevalent and constantly improving. However, continued research needs to be done to address shortcomings, such as low sensitivity, poor specificity, and poor readiness for integration into research use and patient care. The objective of this research was to create a combined fluidic, chip-based biosensor that could detect different biomarkers with high sensitivity and ease of use. For assessing the developed sensor, three separate biomarkers were tested: glucose, cholesterol, and oxygen. Both the glucose biosensor and cholesterol biosensor were combined with …

Green-Route Synthesis Of Halide Perovskite Materials And Their Optoelectronic Properties, Xiaobing Tang

Theses and Dissertations--Chemical and Materials Engineering

Colloidal semiconductor quantum dots (QDs), also called as nanocrystals (NCs), are a class of functional materials with extraordinary properties, which are different from their bulk counterparts and benefit from their exclusive quantum confinement (size) effect. Semiconductor exhibits the quantum confinement effect when the characteristic size of the semiconductor is comparable to or smaller than the de Broglie wavelength of the electron wave function and/or the exciton Bohr diameter of the bulk semiconductor. In recent years, metal halide perovskite NCs, as next-generation semiconductor materials for lighting and display, have aroused a wide attention due to their excellent optoelectronic properties. However, traditional …

The Study Of 3d Micro-Fluid Printing In Aqueous Two-Phase System, Mian Huang

Dissertations and Theses

Aqueous two-phase system (ATPS) is a technology that allows phase separation in an aqueous environment. This technology can be used for the separation, extraction and purification of a variety of biomolecules and thus gained great attention in industry and academia. This thesis is a combination of ATPS, 3D printing, and microfluidics technologies and realizes the printing of biocompatible aqueous structures in another aqueous matrix. The objectives of this thesis include 1) customizing a regular thermal extrusion 3D printer for printing 3D aqueous structures, 2) printing 3D aqueous structure in an aqueous matrix, and 3) studying the stability of the printed …

Quantifying Components Of Protein Translation And Metabolite Heterogeneity In Isogenic Microbial Populations, Alexander Schmitz

McKelvey School of Engineering Theses & Dissertations

Cell-to-cell variation in gene expression and metabolite levels have a significant impact on ensemble productivity of microbial bioproduction. New metabolic engineering tools and approaches are needed that consider cell cultures as an amalgam of uniquely behaving individuals to improve the slow commercialization of metabolically engineered systems. Stochastic cellular process including gene expression, metabolism, and growth lead to phenotypic variation between genetically identical cells. Understanding and the ability to control microbial phenotypic variation is key to improving microbial bioproduction metrics. During protein translation, codon usage strongly influences ensemble gene expression but the effect on the variation of gene expression was not …

Characteristics Analysis Of Electrochemical Impedance Spectroscopy (Eis) For Different Electrode Patterns, Shanzida Kabir

Theses and Dissertations

Electrochemical impedance spectroscopy (EIS) is a rapidly developing technique used in characterizing materials and interfaces. Using equivalent circuits as models can determine the electrical properties of heterogeneous systems like membranes or electrolytes. Different electrochemical processes like the electron transfer rate of a specific reaction or the capacitive behavior of the system, or even the diffusion-limited response can coincide. EIS is applicable to determine different electrochemical processes that can happen simultaneously. The purpose of this research is to find the optimal operating range for other AC electrokinetic mechanisms. Analysis of EIS can be helpful in both fundamental examinations of electrokinetic transport …

Gradient Generating Microfluidic Coculture System For Disease Modeling And Neural Development, Phaneendra Chennampally

Electronic Theses and Dissertations

Cellular microenvironment or cell niche plays an important role in developmental biology and disease pathophysiology. Physical or chemical signals in microenvironment drive the cellular activity. These signaling molecules are generated from the surrounding cells/tissues as part of intercellular communication; a fundamental property of a cell. Dynamic profile of these signaling molecules in the microenvironment plays a pivotal role in transfer of molecular information from cell to cell in disease proliferation or fate determination. Recapitulating these signaling cues in an in vitro study is difficult to achieve using standard cell culture techniques. However microfluidic systems are capable of addressing these issues, …

Active Fluids: Rheological Properties And Response To Light Of Suspensions Of Synechocystis Sp. Cpcc 534, Zahra Habibi

Electronic Thesis and Dissertation Repository

Despite our current understanding of active fluid mechanics, more knowledge is required to fully understand their rheological properties, response to light, and details of the interactions between cells in diluted suspensions.

The focus of this thesis is on investigating the rheological properties of suspensions of cyanobacterium Synechocystis sp. CPCC 534 under shear, induced by stirring. Experiments were conducted at different stirring rates and results are compared with the stationary condition. A notable increase in growth and biomass of Synechocystis sp. under various shear conditions was observed and the yield was nearly doubled. Besides, the data showed Newtonian behavior for suspensions …

An Integrated Model Of Optofluidic Biosensor Function And Performance, Joel Greig Wright, Jr.

Theses and Dissertations

Optofluidic flow-through biosensor devices have been in development for fast bio-target detection. Utilizing the fabrication processes developed by the microelectronics industry, these biosensors can be fabricated into lab-on-a-chip devices with a degree of platform portability. This biosensor technology can be used to detect a variety of targets, and is particularly useful for the detection single molecules and nucleic acid strands. Microfabrication also offers the possibility of production at scale, and this will offer a fast detection method for a range of applications with promising economic viability. The development of this technology has advanced to now warrant a descriptive model that …

Development Of A Microfluidic Viscoelastic Hemostatic Assay For Real-Timeviscosity Measurements Of Blood, Shay Kent

Electronic Theses and Dissertations

Blood coagulation disorders are malfunctions in the body’s ability to control blood clotting. It can result in either insufficient clotting causing an increased risk of bleeding or excessive clotting obstructing blood flow. The rapid and accurate diagnosis of coagulopathies is an important, unmet need in the clinical setting. Rapidly identifying the source of bleeding, either acquired or inherited, is critical to reduce the risk of major blood loss and deliver personalized hemostatic therapies. Viscoelastic hemostatic assays, or VHAs, deliver an effective solution to the diagnosis of coagulopathies by evaluating global hemostatic function using whole blood rather than plasma. VHAs are …

Highly Integrated And Miniaturized 3d Printed Serial Dilution Microfluidic Devices For Dose-Response Assays, Jose Luis Sanchez Noriega

Theses and Dissertations

The ability to generate a range of concentrations of various solutions rapidly and conveniently is an ongoing need in biotechnology. In this thesis we demonstrate how we took advantage of the full process control afforded by our recent custom high resolution 3D printer and resin advances to realize highly integrated and miniaturized microfluidic components for simultaneous on-chip serial dilution for dose-response assays. With judicious selection of mixed layer thicknesses and pixel-by-pixel dose control, we show that the diameter of 3D printed membrane valves can be reduced from 300 µm to 46 µm. We further introduce an entirely new kind of …

Development Of Multifunctional Drug Delivery Systems For Locoregional Therapy, Xinyi Li

Electronic Thesis and Dissertation Repository

Locoregional treatment is the specific delivery of therapeutics to their desired sites of action with minimized systemic adverse effects. In this approach, drug is administered through topical instillation, inhalation, intra-lesional or intra-arterial injection. Decades of experience in locoregional treatment have delivered meaningful benefits to patients with localized diseases (e.g., osteoarthritis, ocular disorders and liver cancers). However, improvements are required for this type of treatment to be more effective. For transarterial chemoembolization (TACE) therapy of hepatocellular carcinoma (HCC), the most current approaches do not allow repeat treatment as the drug delivery vehicle is not degradable. In addition, image contrast agents for …