Date of Graduation

5-2019

Document Type

Thesis

Degree Name

Bachelor of Science in Biomedical Engineering

Degree Level

Undergraduate

Department

Biomedical Engineering

Advisor/Mentor

Tian, Ryan

Abstract

Temperature sensitive hydrogels have been used as injectable hydrogels because the polymer solutions can be liquid at room temperature and gel at body temperature. Injectable hydrogels have been used in biomedical applications to deliver drugs and other small molecules throughout the body. Methylene Blue was used as the drug in this study for its antioxidant and neuroprotective properties. PluronicⓇ F127 (PF127) is a copolymer consisting of repeating units of polyethylene oxide and polypropylene oxide in the form PEO-PPO-PEO. PF127 in solution is a temperature sensitive hydrogel that transitions to a gel at body temperature at specific polymer compositions. A standard set of hydrogels was made with 17, 18, 19 and 20% composition PF127 in deionized water and 15.6 microliters of MB. Phosphate buffered saline was added to the hydrogels and measured daily for their absorbance values to determine the concentration of Methylene Blue that had been released. In an attempt to control drug release, other polymers were added to PF127 solutions. Polyethylene glycol (PEG) has been known to increase the degradation rate of compounds due to its large degree of hydrophilicity. A 1% composition of PEG was added to PF127 gels of 17 through 20% and studied for drug release. It was expected that PEG would increase the degradation rate and therefore the release rate of methylene blue. The gels with PEG behaved as expected while also increasing the gelation time. Polyvinyl alcohol was added in the amount of 1% for the opposite effect. PVA is hydrophilic like PEG, but is a polymerization stabilizer possibly due to its ability to form hydrogen bonds. Although the PVA solution gelled at body temperature, a clump formed in the solution that could have inhibited drug release.

Keywords

injectable hydrogel; programmable release; Methylene Blue

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