Browsing by Author "Dunshee, Lucas C."
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Item Development and characterization of extracellular matrix inspired peptides for nanoparticle self-assembly(University of Delaware, 2017) Dunshee, Lucas C.The extracellular matrix (ECM) is a dense mesh-like network of proteins, proteoglycans, and glycoproteins that imparts physical stability to tissues and plays key roles in cell signaling and behavior such as cell adhesion, proliferation, differentiation, and survival. Physiochemical irregularities or disruptions to certain components of the ECM, such as collagen, can lead to diseases like osteogenesis imperfecta, and osteoarthritis. Current systemic delivery approaches to treat such diseases suffer from off-target effects, suggesting a significant need for ECM targeted therapeutics. ☐ In the last decade ECM inspired polypeptide materials, including elastin like peptides (ELPs) and collagen-like peptides (CLPs), have garnered significant interest in the field of drug delivery. This is owed to the general biocompatibility and thermoresponsivity of both peptides, but also the ability of CLP to target and hybridize to denatured collagen protein in the body. Recently, our group has reported on the assembly of thermoresponsive elastin-b-collagen like peptide nanovesicles that are capable of dissociating at high temperature (70°C). In an effort to modify this temperature of dissociation, and in turn the temperature of CLP-collagen hybridization, a small library of CLP sequences was synthesized. The propensity of four different CLP sequences to form triple helices was measured using circular dichroism wavelength scans and the melting temperatures for each were determined. Characterization of the inverse transition temperature of two different ELP sequences was also completed through light scattering experiments to ensure its role in nanoparticle formation. ☐ Lastly the conjugation of a particular ELP to a small selection of CLPs was performed and characterized for their ability to form nanoparticles. The melting temperature and repeat length of the CLP domain was found to be of critical importance to nanoparticle formation, with one CLP forming particles, while the same CLP with a single repeat unit shorter was not. The ability of these two conjugate systems to form nanoparticles was correlated with their overall triple helical stability and melting temperature. Additionally, the conjugate that was shown to form particles was found to possess characteristics that were more idealized for drug delivery than the previous system. Future work will be focused on determining if the effect of the nanoparticle formation and lower critical solution temperature properties of the particle is a result of CLP triple helical melting temperature or simply an artefact of assembly of a particle with a smaller hydrophilic volume fraction.Item Heuristics of self-assembly, thermoresponsivity and drug release with extracellular matrix inspired peptide nanovesicles(University of Delaware, 2021) Dunshee, Lucas C.The field of nanomedicine is currently blossoming as is evidenced by the creation of the COVID-19 nanovaccines which have now inoculated millions of people in the United States (and world-wide) for protection from the SARS-CoV-2 virus. Additionally, the number of nanomedicines being studied in clinical trials continues to rise as pharmaceutical companies invest more into their research and development. Yet many nanomedicines that carry drug or gene therapeutic molecules (nanocarriers) still employ technologies and strategies that have been utilized for several decades. While this enables a more facile translation of nanocarriers to the clinic, it restricts nanocarriers to a relatively small functional landscape despite there being enormous potential for more advanced nanocarrier systems to better aid the treatment of diseases. ☐ One type of advanced next generation nanomedicines that are of particular interest are stimuli-responsive nanocarriers that can respond either to endogenous cues that are found within the body (e.g., pH and redox stimuli) or exogenous cues (e.g., temperature, light, or magnetism) that can be applied to a living system externally. Such stimuli-responsive systems are advantageous as they can either directly respond to a diseased tissue microenvironment or can be used as a means to spatially and temporally control therapeutic delivery by applying the external stimulus wherever and whenever it is needed by the clinician. Although stimuli-responsive systems have been reported in the literature before, their application and benefits remain unclear. ☐ To address this apparent lacuna, herein is described a novel extracellular matrix inspired peptide nanovesicle system that possesses dual temperature stimuli-responsivity that is thought to be potentially applicable to many different diseases. Specifically, this dissertation describes the design of elastin-like-block-collagen-like peptide (ELP-CLP) amphiphilic conjugates that are capable of thermoresponsive self-assembly and disassembly. A heuristic, but rationale approach is utilized to determine how sequence specific effects of both the collagen-like peptide domain and the elastin-like peptide domain modulate the thermal stability of ELP-CLP nanovesicles. These effects are also studied in the presence of a model therapeutic drug compound and how the thermal properties of these nanovesicles can modify the rate of drug release to an external environment. We additionally explore the potential functionality of these ELP-CLP nanovesicles as future nanocarriers through in vivo retention and characterization work. The total sum of this work shows some of the first preliminary evidence that these ELP-CLP nanovesicles can serve as functional and applicable next generation nanomedicines for the benefit of improved therapeutic outcomes.