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Title:Rotavirus interactions with silica and natural organic matter
Author(s):Gutierrez Garces, Leonardo
Director of Research:Nguyen, Thanh H.
Doctoral Committee Chair(s):Nguyen, Thanh H.
Doctoral Committee Member(s):Mariñas, Benito J.; Werth, Charles J.; Granick, Steve
Department / Program:Civil & Environmental Eng
Discipline:Environ Engr in Civil Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Atomic Force Microscopy
Natural Organic Matter
Dynamic Light Scattering
Quartz Crystal Microbalance
Abstract:Rotavirus is a leading cause of gastrointestinal infections worldwide resulting in severe diarrhea and dehydration among children (Parashar et al., 2006). Rotavirus “ubiquitous” occurrence in water systems raises fundamental questions regarding interactions with surfaces that may affect its fate and transport. Consequently, the main objectives of this study were: 1) investigate the mechanisms that govern rotavirus interactions with environmental surfaces; and 2) examine the role of solution chemistry on these mechanisms. Interactions between rotavirus particles under different solution chemistries were studied by time-resolved dynamic light scattering. No rotavirus aggregation was observed in NaCl solutions of up to 600 mM whether in the presence or absence of Suwannee Riven natural organic matter (SRNOM). Rotavirus aggregation was detected in SRNOM and divalent cation-containing solutions, and was faster than in the solely presence of divalent cations. Calculated attachment efficiencies were always higher in CaCl2 than MgCl2 solutions of the same concentration. Deposition of rotavirus on silica or SRNOM-coated silica surface was studied using quartz crystal microbalance technique. Experimental attachment efficiencies for rotavirus adsorption to silica or SRNOM-coated surface in MgCl2 solution were lower than in CaCl2 of the same concentration. No rotavirus deposition on both surfaces was observed in NaCl solutions. Atomic force microscopy (AFM) was used as a complementary technique to study interaction forces at the nano-scale. Decay lengths at different NaCl concentrations showed non-electrostatic repulsive forces as mainly responsible for eliminating rotavirus aggregation. Stronger adhesion forces were measured for rotavirus-rotavirus and rotavirus-SRNOM interactions in CaCl2 compared to those in MgCl2 solutions of the same concentration. Rotavirus interactions with two NOM isolates of different characteristics in NaCl solutions were studied by AFM. Colorado River-NOM (CRW) and SRNOM were selected as model non-humic and humic NOM, respectively. Rotavirus showed repulsive forces to SRNOM during approaching regime and no adhesion during retraction even at high ionic strength. Attractive forces were observed between rotavirus and CRW during approaching and high adhesion during retraction. These results indicate two different mechanisms based on the dissimilar characteristics of the two NOM isolates. Additional control experiments suggest ionic hydrogen bond-based and electrosteric-based interactions as major mechanism between rotavirus-CRW and rotavirus-SRNOM, respectively. Besides electrostatics, results from this study suggest that steric repulsion, acid-base interactions, and divalent cation complexation with carboxylate groups on rotavirus surface and NOM are important mechanisms controlling rotavirus deposition and aggregation. In addition, the specific surface characteristics of NOM and solution ionic composition have a profound effect on the interactions with rotavirus that might affect its fate and transport in water systems.
Issue Date:2013-08-22
Rights Information:Copyright 2013 Leonardo Gutierrez Garces
Date Available in IDEALS:2013-08-22
Date Deposited:2013-08

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