Development of Poly(ethylene glycol)-Based Hydrogels for the Enterosorptive Removal of Carcinogens and Their Precursors

Carcinogens and their precursors, with their inherently negative reputation, are far more prevalent than many people may think. Nitrates, for one, are naturally occurring chemicals to which many people are exposed on a regular dietary basis. Typically found in leafy vegetables and as meat preservatives, multiple studies have linked them to different types of cancers (e.g. colorectal, esophageal, thyroid), despite their potential cardiovascular health benefits. When consumed, nitrates can undergo a series of reactions that result in the production of nitrosamines, a subsection of N-nitroso compounds (NOCs), many of which have been declared carcinogenic. While much of the dietary nitrate intake is often excreted, bioaccumulation may still occur; and since avoiding exposure is impractical for most people, an alternative is to develop an enterosorbent to remove the nitrates from the body before they become carcinogenic. Poly(ethylene glycol) diacrylate (PEGDA) is a monomer that when combined with cationic comonomer (3-acrylamidopropyl)trimethylammonium chloride (DMAPA-Q), formed a hydrogel composite to which powdered activated carbon (PAC) could be added as an additional adsorbent. The hydrogels were then characterized using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), mass conversion, and swelling studies in DI water. Ultimately, sorption studies were conducted to determine nitrate removal efficiencies across various systems. Results demonstrated that increasing the relative amount of DMAPA-Q provided a higher swelling capacity and removal efficiency that plateaued around 75% at a 0.5 mg/mL sorbent dose due to the dominant assumed charge-based affinity. Thus, these systems have the potential for nitrate enterosorption and may be applied to other carcinogenic targets.