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With microspheres growing in popularity as viable systems for targeted drug therapeutics, there exist a host of diseases and pathology induced side effects which could be treated with poly(lactic-co-glycolic acid) [PLGA] microparticle systems [6,10,12]. While PLGA systems are already applied in a wide variety the clinical setting [11], microparticles still

With microspheres growing in popularity as viable systems for targeted drug therapeutics, there exist a host of diseases and pathology induced side effects which could be treated with poly(lactic-co-glycolic acid) [PLGA] microparticle systems [6,10,12]. While PLGA systems are already applied in a wide variety the clinical setting [11], microparticles still have some way to go before they are viable systems for drug delivery. One of the main reasons for this is a lack of fabrication processes and systems which produce monodisperse particles while also being feasible for industrialization [10]. This honors thesis investigates various microparticle fabrication techniques \u2014 two using mechanical agitation and one using fluid dynamics \u2014 with the long term goal of incorporating norepinephrine and adenosine into the particles for metabolic stimulatory purposes. It was found that mechanical agitation processes lead to large values for dispersity and the polydispersity index while fluid dynamics methods have the potential to create more uniform and predictable outcomes. The research concludes by needing further investigation into methods and prototype systems involving fluid dynamics methods; however, these systems yield promising results for fabricating monodisperse particles which have the potential to encapsulate a wide variety of therapeutic drugs.
ContributorsRiley, Levi Louis (Author) / Vernon, Brent (Thesis director) / VanAuker, Michael (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
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Locomotion of microorganisms is commonly observed in nature. Although microorganism locomotion is commonly attributed to mechanical deformation of solid appendages, in 1956 Nobel Laureate Peter Mitchell proposed that an asymmetric ion flux on a bacterium's surface could generate electric fields that drive locomotion via self-electrophoresis. Recent advances in nanofabrication have

Locomotion of microorganisms is commonly observed in nature. Although microorganism locomotion is commonly attributed to mechanical deformation of solid appendages, in 1956 Nobel Laureate Peter Mitchell proposed that an asymmetric ion flux on a bacterium's surface could generate electric fields that drive locomotion via self-electrophoresis. Recent advances in nanofabrication have enabled the engineering of synthetic analogues, bimetallic colloidal particles, that swim due to asymmetric ion flux originally proposed by Mitchell. Bimetallic colloidal particles swim through aqueous solutions by converting chemical fuel to fluid motion through asymmetric electrochemical reactions. This dissertation presents novel bimetallic motor fabrication strategies, motor functionality, and a study of the motor collective behavior in chemical concentration gradients. Brownian dynamics simulations and experiments show that the motors exhibit chemokinesis, a motile response to chemical gradients that results in net migration and concentration of particles. Chemokinesis is typically observed in living organisms and distinct from chemotaxis in that there is no particle directional sensing. The synthetic motor chemokinesis observed in this work is due to variation in the motor's velocity and effective diffusivity as a function of the fuel and salt concentration. Static concentration fields are generated in microfluidic devices fabricated with porous walls. The development of nanoscale particles that swim autonomously and collectively in chemical concentration gradients can be leveraged for a wide range of applications such as directed drug delivery, self-healing materials, and environmental remediation.
ContributorsWheat, Philip Matthew (Author) / Posner, Jonathan D (Thesis advisor) / Phelan, Patrick (Committee member) / Chen, Kangping (Committee member) / Buttry, Daniel (Committee member) / Calhoun, Ronald (Committee member) / Arizona State University (Publisher)
Created2011
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Description

Polymer drug delivery system offers a key to a glaring issue in modern administration routes of drugs and biologics. Poly(lactic-co-glycolic acid) (PLGA) can be used to encapsulate drugs and biologics and deliver them into the patient, which allows high local concentration (compared to current treatment methods), protection of the cargo

Polymer drug delivery system offers a key to a glaring issue in modern administration routes of drugs and biologics. Poly(lactic-co-glycolic acid) (PLGA) can be used to encapsulate drugs and biologics and deliver them into the patient, which allows high local concentration (compared to current treatment methods), protection of the cargo from the bodily environment, and reduction in systemic side effects. This experiment used a single emulsion technique to encapsulate L-tyrosine in PLGA microparticles and UV spectrophotometry to analyze the drug release over a period of one week. The release assay found that for the tested samples, the released amount is distinct initially, but is about the same after 4 days, and they generally follow the same normalized percent released pattern. The experiment could continue with testing more samples, test the same samples for a longer duration, and look into higher w/w concentrations such as 20% or 50%.

ContributorsSeo, Jinpyo (Author) / Vernon, Brent (Thesis director) / Pal, Amrita (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description

Traumatic brain injury (TBI), a neurological condition that negatively affects neural capabilities, occurs when a blunt trauma impacts the head. Following the initial injury that immediately impacts neural cell function and survival, a series of secondary injury events lead to substantial sustained inflammation for weeks to years post-injury. To develo

Traumatic brain injury (TBI), a neurological condition that negatively affects neural capabilities, occurs when a blunt trauma impacts the head. Following the initial injury that immediately impacts neural cell function and survival, a series of secondary injury events lead to substantial sustained inflammation for weeks to years post-injury. To develop TBI treatments that may stimulate regenerative processes, a novel drug delivery system that efficiently delivers the appropriate drug/payload to injured tissue is crucial. Hyaluronic acid (HA) hydrogels are attractive when developing a biomaterial for tissue reparation and regeneration. HA is a natural polymer with physicochemical properties that can be tuned to match the properties of the extracellular matrix (ECM) of the many tissues including the central nervous system (CNS). Here, the project objective was to develop a HA hydrogel system for local delivery of a biological payload; this objective was completed by employing a composite system with two parts. The first part is an injectable, shear-thinning bulk hydrogel, and the second is microgels for loading biological payloads. The bulk hydrogel was composed of cyclodextrin modified HA (Cd-HA) and adamantane modified HA (Ad-HA) that give rise to guest-host interactions that facilitate physical crosslinking. The microgel, composed of norbornene-HA (Nor-HA) and sulfated-HA, crosslink via chemical crosslinks upon activation of a UV photoinitiator. The sulfated-HA microgels facilitate loading of biological payloads by mimicking heparin binding sites via the conjugated sulfated group. Neuregulin I, an epidermal growth factor with neuroprotective properties, is one such protein with a heparin binding domain that may be retained in the sulfated-HA microgels. Specifically, the project focused on mechanical testing of this composite microgel/hydrogel system and also developing protein affinity assays.

ContributorsKylat, Anna (Author) / Stabenfeldt, Sarah (Thesis director) / Holloway, Julianne (Committee member) / Jensen, Gregory (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Harrington Bioengineering Program (Contributor)
Created2023-05
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Description
The aim of the present study was to review the symptoms and current treatment options of the most common skin infections seen in outpatient settings and develop a preliminary alternative treatment solution. The specific skin infections evaluated were those caused by Staphylococcus and Streptococcus bacterial species, and are frequently treated

The aim of the present study was to review the symptoms and current treatment options of the most common skin infections seen in outpatient settings and develop a preliminary alternative treatment solution. The specific skin infections evaluated were those caused by Staphylococcus and Streptococcus bacterial species, and are frequently treated with a wide variety of systemic antibiotics or topical ointments. Systemic antibiotics have shown increased occurrence of adverse side effects as well as the development of antibiotic-resistant bacteria. Additionally, these medications are usually overprescribed, which may further exacerbate negative side effects. Another issue that is addressed is the development of infections following treatment of a new laceration or other trauma to the skin. A patient may be treated for their wound with stitches or another alternative, but there is still the possibility of developing an infection later.
This study synthesizes information found from extensive research and provides a review of the most optimal techniques for developing an alternative to systemic antibiotics. The final deliverable is a report detailing the significant findings and discussing the ways that this solution may be developed further and implemented in a clinical setting. The solution is a hydrogel bandage designed to deliver antibiotics directly to the wound site, while also offering protection and enhanced wound healing. The target population is patients suffering from skin conditions in an outpatient setting. The antibiotics of interest for this solution are clindamycin, doxycycline, and trimethoprim-sulfamethoxazole (co-trimoxazole), as they offer excellent treatment against gram-positive bacteria and methicillin-resistant Staphylococcus aureus. However, other broad-spectrum antibiotics could potentially be incorporated to protect against gram-negative bacteria. The design features a polyvinyl alcohol (PVA) hydrogel that has shown many properties that are beneficial to biomedical applications, including biocompatibility, flexibility, high drug-loading capacity, high absorption of wound exudate, increased promotion of wound healing, and more. Preliminary mathematical models of the hydrogel’s drug delivery behaviors are also included. Due to the scope and timeframe of this project, the majority of findings herein are based on research of prior literature instead of development of the novel device. Future directions would include further research and development of the mechanisms behind the device, creation of a physical prototype, experimental testing, and statistical analyses to verify device specifications and capabilities.
ContributorsTanner, Emily Christine (Author) / Pizziconi, Vincent (Thesis director) / Nguyen, Eric (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05