Interactions between Rotavirus and Suwannee River Organic Matter: Aggregation, Deposition, and Adhesion Force Measurement Leonardo Gutierrez Thanh H. Nguyen 10.1021/es301336u.s001 https://acs.figshare.com/articles/journal_contribution/Interactions_between_Rotavirus_and_Suwannee_River_Organic_Matter_Aggregation_Deposition_and_Adhesion_Force_Measurement/2494435 Interactions between rotavirus and Suwannee River natural organic matter (NOM) were studied by time-resolved dynamic light scattering, quartz crystal microbalance, and atomic force microscopy. In NOM-containing NaCl solutions of up to 600 mM, rotavirus suspension remained stable for over 4 h. Atomic force microscopy (AFM) measurement for interaction force decay length at different ionic strengths showed that nonelectrostatic repulsive forces were mainly responsible for eliminating aggregation in NaCl solutions. Aggregation rates of rotavirus in solutions containing 20 mg C/L increased with divalent cation concentration until reaching a critical coagulation concentration of 30 mM CaCl<sub>2</sub> or 70 mM MgCl<sub>2</sub>. Deposition kinetics of rotavirus on NOM-coated silica surface was studied using quartz crystal microbalance. Experimental attachment efficiencies for rotavirus adsorption to NOM-coated surface in MgCl<sub>2</sub> solution were lower than in CaCl<sub>2</sub> solution at a given divalent cation concentration. Stronger adhesion force was measured for virus–virus and virus–NOM interactions in CaCl<sub>2</sub> solution compared to those in MgCl<sub>2</sub> or NaCl solutions at the same ionic strength. This study suggested that divalent cation complexation with carboxylate groups in NOM and on virus surface was an important mechanism in the deposition and aggregation kinetics of rotavirus. 2012-08-21 00:00:00 CaCl 2 solution NaCl solutions divalent cation complexation Suwannee River Organic Matter rotaviru AFM 70 mM MgCl 2. Deposition kinetics NOM MgCl 2 solution divalent cation concentration interaction force decay length Experimental attachment efficiencies quartz crystal microbalance Atomic force microscopy surface Adhesion Force MeasurementInteractions 30 mM CaCl 2 virus