AVS 65th International Symposium & Exhibition
    Biomaterial Interfaces Division Tuesday Sessions
       Session BI-TuP

Paper BI-TuP8
Developing a pH Responsive Hydrogel for the Encapsulation of Poly(ethylene glycol) 3350

Tuesday, October 23, 2018, 6:30 pm, Room Hall B

Session: Biomaterial Interfaces Division Poster Session
Presenter: Phuong Anh Nguyen, University of New Mexico
Authors: P.A. Nguyen, University of New Mexico
B. Matheson, University of New Mexico
D. Cuylear, University of New Mexico
H.E. Canavan, University of New Mexico
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Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States. The most reliable screening method of CRC is a colonoscopy which requires a 4-Liter poly(ethylene glycol) electrolyte lavage solution (PEG-ELS) for preparation. Two in five patients are non-compliant to their colonoscopy schedules, with many patients who abstain reporting refusal due to significant discomfort associated with this preparation. Furthermore, there are distinct gender differences in the tolerance of PEG-ELS in male and female populations. We hypothesize the differences in clinic are a result of cytotoxicity effects of PEG. PEG is approved by the FDA for use in medical devices, and has been recognized for many years as a biocompatible/bioinert polymer but few studies have truly studied the short-term and long-term effects of high concentrations of PEG on multiple cell lines. We have developed a pH responsive hydrogel to control the release of PEG – reducing adverse effects associated with colonoscopy preparations. The hydrogels have been characterized using NMR, FTIR, and XPS to ensure chemical identity, rheometry to assess the stiffness/robustness of the hydrogels in varying environments, and SEM and other techniques to confirm uniformity of size. Biocompatibility testing of exposure to increasing PEG concentrations over a period of 3 hours, 6 hours, 12 hours, 24 hours, and 48 hours shows PEG is biocompatible to mammalian cell lines in low concentrations, and in fact, increases their growth and viability. At higher concentrations, however, PEG is cytotoxic to cells. Although it would be difficult to get to toxic levels of PEG in the body in a single dose, current uses of PEG should be re-evaluated due to possible adverse cumulative effects due to the cytotoxicity effects seen in vitro. Further directions of this work will evaluate the pH responsiveness of our hydrogel formulation to deliver PEG in vitro and in vivo, and assessment of the cellular response to the hydrogels using mammalian cells specific to the gastrointestinal system of humans, as well as imaging analysis to envision their penetration.