Theses and Dissertations
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- Creators: Barrett, The Honors College
This analysis explores what the time needed to harden, and time needed to degrade is of a PLGA bead, as well as whether the size of the needle injecting the bead and the addition of a drug (Vismodegib) may affect these variables. Polymer degradation and hardening are critical to understand for the polymer’s use in clinical settings, as these factors help determine the patients’ and healthcare providers’ use of the drug and estimated treatment time. Based on the literature, it is expected that the natural logarithmic polymer mass degradation forms a linear relationship to time. Polymer hardening was tested by taking video recordings of gelatin plates as they are injected with microneedles and performing RGB analysis on the polymer “beads” created. Our results for the polymer degradation experiments showed that the polymer hardened for all solutions and trials within approximately 1 minute, presenting a small amount of time in which the patient would have to remain motionless in the affected area. Both polymer bead size and drug concentration may have had a modest impact on the hardening time experiments, while bead size may affect the time required for the polymer to degrade. Based on the results, the polymer degradation is expected to last multiple weeks, which may allow for the polymer to be used as a long-term drug delivery system in treatment of basal cell carcinoma.
We describe a secondary analysis of an in vitro experiment that supports the capabilities of a relatively new imaging technique known as functional Magnetic Resonance Electrical Impedance Tomography (fMREIT) to detect conductivity changes in neural tissue caused by activity. Methods: Magnetic Resonance (MR) phase data of active Aplysia ganglia tissue in artificial seawater (ASW) were collected before and after exposure to an excitotoxin using two different imaging current strengths, and these data were then used to reconstruct conductivity changes throughout the tissue. Results: We found that increases in neural activity led to significant increases in imaged conductivity when using high imaging currents, but these differences in conductivity were not seen in regions that did not contain neural tissue nor in data where there were no differences in neural activity. Conclusion: We conclude that the analysis presented here supports fMREIT as a contrast technique capable of imaging neural activity in live tissue more directly than functional imaging methods such as BOLD fMRI.