Edible sorbents to reduce the bioavailability of hazardous pollutants during disasters, outbreaks and emergencies

Specific Aim 1. Investigate and characterize environmental chemical/sorbent interactions, including surface affinities, capacities, and thermodynamics. We hypothesize that high-affinity, high-capacity sorbent materials and broad-acting mixtures of these materials will reduce the bioavailability and toxicity of chemical mixtures that are mobilized during disaster emergencies. First, we will screen and select sorbent materials with the potential to bind multiple chemicals using equilibrium isothermal analysis. The materials studied will include biopolymers, clays and modified clays, fiber, chlorophyll, probiotic bacteria, chitosan, and other materials that have been shown to have high affinities and high capacities for prioritized chemicals. We will then validate binding by determining indices of chemisorption, specificity, affinity (Kd), capacity (Qmax), and enthalpy (ΔH) of adsorption from isothermal analyses in water and simulated gastric and intestinal fluids. Finally, we will confirm in vivo the efficacy and safety of broad-acting sorbents for complex chemical mixtures using a freshwater Cnidarian model (Hydra vulgaris) that is highly sensitive to environmental contaminants.Specific Aim 2. Assess the thermodynamics and mechanisms of sorption for individual chemicals onto the surfaces of selected sorbent materials using computational physical organic chemistry. We hypothesize that computational chemistry strategies can be used to characterize and confirm favorable surface interactions between hazardous chemicals and potential binding materials. These studies will delineate the fundamental chemical mechanisms of effective sorbents and help predict optimal enterosorbent materials. We will construct molecular models based on unit cell coordinates from the literature and molecular prototypes from similar materials. The structures of prioritized sorbents and toxicants will be energy-minimized using a variety of density functional theory (DFT) and semi-empirical molecular orbital methods. These will be complemented by molecular dynamics simulations based on classical molecular mechanical force interactions, which will guide the selection of potential sorbent materials for further experimental characterization.