Matching Items (8)
Filtering by
- All Subjects: Hydrogels
- Creators: Harrington Bioengineering Program
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
- Member of: Theses and Dissertations
- Resource Type: Text
Description
With an increased demand for more enzyme-sensitive, bioresorbable and more biodegradable polymers, various studies of copolymers have been developed. Polymers are widely used in various applications of biomedical engineering such as in tissue engineering, drug delivery and wound healing. Depending on the conditions in which polymers are used, they are modified to accommodate a specific need. For instance, polymers used in drug delivery are more efficient if they are biodegradable. This ensures that the delivery system does not remain in the body after releasing the drug. It is therefore crucial that the polymer used in the drug system possess biodegradable properties. Such modification can be done in different ways including the use of peptides to make copolymers that will degrade in the presence of enzymes. In this work, we studied the effect of a polypeptide GAPGLL on the polymer NIPAAm and compare with the previously studied Poly(NIPAAm-co-GAPGLF). Both copolymers Poly(NIPAAm-co-GAPGLL) were first synthesized from Poly(NIPAAm-co-NASI) through nucleophilic substitution by the two peptides. The synthesis of these copolymers was confirmed by 1H NMR spectra and through cloud point measurement, the corresponding LCST was determined. Both copolymers were degraded by collagenase enzyme at 25 ° C and their 1H NMR spectra confirmed this process. Both copolymers were cleaved by collagenase, leading to an increase in solubility which yielded a higher LCST compared to before enzyme degradation. Future studies will focus on evaluating other peptides and also using other techniques such as Differential Scanning Microcalorimetry (DSC) to better observe the LCST behavior. Moreover, enzyme kinetics studies is also crucial to evaluate how fast the enzyme degrades each of the copolymers.
ContributorsUwiringiyimana, Mahoro Marie Chantal (Author) / Vernon, Brent (Thesis director) / Nikkhah, Mehdi (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This report provides information concerning qualities of methylcellulose and how those properties affect further experimentation within the biomedical world. Utilizing the compound’s biocompatibility many issues, ranging from surgical to cosmetic, can be solved. As of recent, studies indicate, methylcellulose has been used as a physically cross-linked gel, which cannot sustain a solid form within the body. Therefore, this report will ultimately explore the means of creating a non-degradable, injectable, chemically cross-linking methylcellulose- based hydrogel. Methylcellulose will be evaluated and altered in experiments conducted within this report and a chemical cross-linker, developed from Jeffamine ED 2003 (O,O′-Bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol), will be created. Experimentation with these elements is outlined here, and will ultimately prompt future revisions and analysis.
ContributorsBundalo, Zoran Luka (Author) / Vernon, Brent (Thesis director) / LaBelle, Jeffrey (Committee member) / Overstreet, Derek (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2013-05
Description
Previous studies have found that the detection of near-threshold stimuli is decreased immediately before movement and throughout movement production. This has been suggested to occur through the use of the internal forward model processing an efferent copy of the motor command and creating a prediction that is used to cancel out the resulting sensory feedback. Currently, there are no published accounts of the perception of tactile signals for motor tasks and contexts related to the lips during both speech planning and production. In this study, we measured the responsiveness of the somatosensory system during speech planning using light electrical stimulation below the lower lip by comparing perception during mixed speaking and silent reading conditions. Participants were asked to judge whether a constant near-threshold electrical stimulation (subject-specific intensity, 85% detected at rest) was present during different time points relative to an initial visual cue. In the speaking condition, participants overtly produced target words shown on a computer monitor. In the reading condition, participants read the same target words silently to themselves without any movement or sound. We found that detection of the stimulus was attenuated during speaking conditions while remaining at a constant level close to the perceptual threshold throughout the silent reading condition. Perceptual modulation was most intense during speech production and showed some attenuation just prior to speech production during the planning period of speech. This demonstrates that there is a significant decrease in the responsiveness of the somatosensory system during speech production as well as milliseconds before speech is even produced which has implications for speech disorders such as stuttering and schizophrenia with pronounced deficits in the somatosensory system.
ContributorsMcguffin, Brianna Jean (Author) / Daliri, Ayoub (Thesis director) / Liss, Julie (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Previous research has shown that a loud acoustic stimulus can trigger an individual's prepared movement plan. This movement response is referred to as a startle-evoked movement (SEM). SEM has been observed in the stroke survivor population where results have shown that SEM enhances single joint movements that are usually performed with difficulty. While the presence of SEM in the stroke survivor population advances scientific understanding of movement capabilities following a stroke, published studies using the SEM phenomenon only examined one joint. The ability of SEM to generate multi-jointed movements is understudied and consequently limits SEM as a potential therapy tool. In order to apply SEM as a therapy tool however, the biomechanics of the arm in multi-jointed movement planning and execution must be better understood. Thus, the objective of our study was to evaluate if SEM could elicit multi-joint reaching movements that were accurate in an unrestrained, two-dimensional workspace. Data was collected from ten subjects with no previous neck, arm, or brain injury. Each subject performed a reaching task to five Targets that were equally spaced in a semi-circle to create a two-dimensional workspace. The subject reached to each Target following a sequence of two non-startling acoustic stimuli cues: "Get Ready" and "Go". A loud acoustic stimuli was randomly substituted for the "Go" cue. We hypothesized that SEM is accessible and accurate for unrestricted multi-jointed reaching tasks in a functional workspace and is therefore independent of movement direction. Our results found that SEM is possible in all five Target directions. The probability of evoking SEM and the movement kinematics (i.e. total movement time, linear deviation, average velocity) to each Target are not statistically different. Thus, we conclude that SEM is possible in a functional workspace and is not dependent on where arm stability is maximized. Moreover, coordinated preparation and storage of a multi-jointed movement is indeed possible.
ContributorsOssanna, Meilin Ryan (Author) / Honeycutt, Claire (Thesis director) / Schaefer, Sydney (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
The main goal of this project was to study and understand the release of gentamicin from in – situ, self – reactive drug delivery gelling matrix. The motivation behind this was to create a drug delivery mechanism for gentamicin and eliminate the need for re–injecting the drug multiple times into the patient. Gentamicin is used to treat various different bacterial infections of the central nervous system, blood, kidneys, gall bladder, bile duct, heart cavity linings, and heart valves. Pentaerythritol–tetrakis
(3 – mercaptoproprionate; QT) was crosslinked with poly(ethylene glycol) diacrylate (PEGDA) having an average molecular weight of 575 with the help of Phosphate Buffer Saline (PBS), with a buffer ionic strength of 0.143M and a pH of 8.9 and 11, for the drug concentrations of 5 mg/mL and 50 mg/mL, respectively. The Michael – type reaction formed the crosslinked self – administering gelling matrix. With the gelling matrix starting to coagulate into a hydrophobic solid in about 5 minutes, the material was injected into Tygon tubing. After complete solidification, the drug – loaded gels were extracted from the tubing and divided into 1 cm cylinders. The cylinders with 5mg/mL and 50mg/mL drug concentration exhibited a sustained and controlled release curve for about 288 hours. This project as well as this drug delivery system can in the future be expanded for use in the delivery of more hydrophobic long – term drugs to the patient.
ContributorsJolly, Nehal (Author) / Vernon, Brent (Thesis director) / Herman, Richard (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Traumatic brain injury (TBI) is a leading cause of death in individuals under the age of 45, resulting in over 50,000 deaths each year. Over 80,000 TBI patients report long-term deficits consisting of motor or cognitive dysfunctions due to TBI pathophysiology. The biochemical secondary injury triggers a harmful inflammatory cascade, gliosis, and astrocyte activation surrounding the injury lesion, and no current treatments exist to alleviate these underlying pathologies. In order to mitigate the negative inflammatory effects of the secondary injury, we created a hydrogel comprised of hyaluronic acid (HA) and laminin, and we hypothesized that the anti-inflammatory properties of HA will decrease astrocyte activation and inflammation after TBI. C57/BL6 mice were subjected to mild-to-moderate CCI. Three days following injury, mice were treated with injection of vehicle or HA-Laminin hydrogel. Mice were sacrificed at three and seven days post injection and analyzed for astrocyte and inflammatory responses. In mice treated with vehicle injections, astrocyte activation was significantly increased at three days post-transplantation in the injured cortex and injury lesion. However, mice treated with the HA-Laminin hydrogel experienced significantly reduced acute astrocyte activation at the injury site three days post transplantation. Interestingly, there were no significant differences in astrocyte activation at seven days post treatment in either group. Although the microglial and macrophage response remains to be investigated, our data suggest that the HA-Laminin hydrogel demonstrates potential for TBI therapeutics targeting inflammation, including acute modulation of the astrocyte, microglia, and macrophage response to TBI.
ContributorsGoddery, Emma Nicole (Author) / Stabenfeldt, Sarah (Thesis director) / Addington, Caroline (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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 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
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 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.
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