(637f) Multifunctional Materials for the Adsorption of Metabolic Toxins with a Focus on Chronic Kidney Disease

According to the CDC, Chronic Kidney Disease (CKD) is the tenth leading cause of death among fatal diseases.¹ Many people do not realize they are suffering from CKD until they reach the end stages, at which point the only treatment options are a kidney transplant or dialysis, which removes uremic toxins from the blood stream. Due to the lack of kidney donors and the possibility that the body will reject the transplanted kidney, the most accessible treatment option available is dialysis, which leads to a significant decrease in quality of life. Recent clinical studies have shown that high-fiber plant-based diets positively influence the gut microbiome and improve disease outcomes for CKD patients. However, there is a scientific void in treatment strategies that focus on removing uremic toxins from the gastrointestinal tract. Using nature as an inspiration, nondigestible cellulose microgel beads are fabricated from food waste to mimic the functionality of dietary fiber and to allow for targeted removal of uremic toxins from the gastrointestinal tract. Cellulose was extracted from food waste using an acid/base washing technique that produced oxidized cellulose at levels comparable to chemically oxidized cotton linter pulp. Using the extracted cellulose, we were able to successfully fabricate microgel beads via a horizontal dropping technique with sizes ranging from 700-1500 μm. This size range prevents the beads from diffusing through the lining of the gastrointestinal tract. The fabricated cellulose beads were subjected to both air and freeze-drying techniques to tune the microstructure and explore changes in porosity and mechanics. In situ mechanical testing of the cellulose microgels revealed that differences in microstructure result in drastically different mechanical behavior in simulated gastric environments. Air-dried beads displayed an order of magnitude increase in Young’s Modulus after the beads were first subjected to simulated gastric fluid and then subjected to simulated intestinal fluid. In contrast, freeze-dried beads displayed no significant difference in mechanics after being exposed to simulated gastric environments. The increase in modulus for air-dried beads, is a unique phenomenon that, to the best of our knowledge, has not yet been reported in the literature. We will discuss the effects of enzyme interactions, pH, and microstructure on the resultant mechanics and survivability in the gastrointestinal tract. Additionally, we will discuss how this cellulose-based sorbent platform will provide new fundamental understanding of transport and diffusion properties throughout the gastrointestinal tract with the goal of removing uremic toxins and providing a patient friendly treatment alternative for CKD.

References:

1)Murphy SL, Xu J, Kochanek KD, Arias E. Mortality in the United States, 2017. NCHS Data Brief. 2018 Nov;(328):1-8. PMID: 30500322.