Characterization of poly(pro-curcumin) polymer thin films and assessment of neuroprotective capabilities in vitro
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Authors
Hamilton, Adelle, Elena
Issue Date
2024-05
Type
Electronic thesis
Thesis
Thesis
Language
en_US
Keywords
Biomedical engineering
Alternative Title
Abstract
Intracortical microelectrodes are utilized in brain-machine interfaces to help restore motor and sensory function in patients who have suffered spinal cord injury. They allow for the potential to observe and record neuronal activity, as well as unite brain-computer interfaces for neuroprosthetics, such as prosthetic limbs. While promising for use in neuroprosthetic technologies, electrode functionality is compromised by biological mechanisms, such as inflammatory cascades, that result from electrode insertion into neural tissue. Curcumin, a naturally occurring compound found in turmeric, is antioxidative and anti-inflammatory and can dampen phenomena related to secondary injury. Curcumin is highly hydrophobic and has low bioavailability, limiting it in clinical applications; thus, it is often conjugated into a polymeric drug delivery system to overcome these limitations. This work aims to characterize different formulations of a poly(curcumin-co-polyethylene glycol) (PEG) polymer, referred to as poly(pro-curcumin), at several concentrations to assess their neuroprotective abilities following stimulated electrode implantation neural injury. The two formulations, P50 (50 mol% curcumin:50 mol% PEG) and P75 (75 mol% curcumin:25 mol% PEG), were cast into polymer films at varying weight percentages. Degradation studies, analyzed via mass loss and scanning electron microscopy, revealed that P50 films at lower concentrations (6% and 8%) degraded almost entirely, while the highest concentration film, 10%, degraded to about half of its mass. Additionally, these studies revealed that the P75 films across all concentrations exhibited very little to no degradation. Overall, these findings demonstrate that polymer hydrophilicity plays a greater role in degradation kinetics than polymer concentrations within the selected range. Finally, the polymer formulations were investigated for their neuroprotective and antioxidant abilities following a stimulated injury to neuronal cultures in vitro. Assessment of the cultures revealed that the P50 and P75 films across all concentrations exhibited neuroprotective effects by reducing cell death, with the P75 films outperforming the P50 films. These results provide evidence that solubilized polymer is not necessary to provide neuroprotective effects; the films are able to quench free radicals at their surface. Collectively, this work is the first to characterize P50 and P75 over several concentrations and to assess their neuroprotective abilities. The findings detailed in this work reveal the degradation kinetics and neuroprotective mechanisms of P50 and P75, and provide insight into the selection of specific poly(pro-) material compositions for future applications.
Description
May2024
School of Engineering
School of Engineering
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY