title: Experimental and modeling studies of sorption of ceria nanoparticle on microbial biofilms.
abstract: This study focuses on the interaction of ceria nanoparticles (CeO2-NPs) with Pseudomonas fluorescens and Mycobacterium smegmatis biofilms. Confocal laser microscopy and transmission electron microscopy determined the distribution of NPs in the complex structures of biofilm at molecular levels. Visual data showed that most of the adsorption takes place on the bacterial cell walls and spores. The interaction of nanoparticles (NPs) with biofilms reached equilibrium after the initial high adsorption rate regardless of biofilm heterogeneity and different nanoparticle concentrations in the bulk liquid. Physical processes may dominate this sorption phenomenon. Pseudo first order sorption kinetics was used to estimate adsorption and desorption rate of CeO2-NPs onto biofilms. When biofilms got exposed to CeO2-NPs, a self-protecting mechanism was observed. Cells moved away from the bulk solution in the biofilm matrix, and portions of biofilm outer layer were detached, hence releasing some CeO2-NPs back to the bulk phase.
authors.affiliation: Environmental Engineering Program, Department of Biomedical, Chemical, and Environmental Engineering, University of Cincinnati, Cincinnati, OH, USA.
authors.forename: Hengye
authors.initials: H
authors.lastname: Jing
authors.affiliation: Environmental Engineering Program, Department of Biomedical, Chemical, and Environmental Engineering, University of Cincinnati, Cincinnati, OH, USA.
authors.forename: Bineyam
authors.initials: B
authors.lastname: Mezgebe
authors.affiliation: Office of Research and Development, NRMRL, US Environmental Protection Agency, Cincinnati, OH, USA.
authors.forename: Ashraf
authors.initials: A
authors.lastname: Aly Hassan
authors.affiliation: Office of Research and Development, NRMRL, US Environmental Protection Agency, Cincinnati, OH, USA. Electronic address: sahle-demessie.endalkachew@epa.gov.
authors.forename: Endalkachew
authors.initials: E
authors.lastname: Sahle-Demessie
authors.affiliation: Environmental Engineering Program, Department of Biomedical, Chemical, and Environmental Engineering, University of Cincinnati, Cincinnati, OH, USA.
authors.forename: George A
authors.initials: GA
authors.lastname: Sorial
authors.affiliation: Office of Research and Development, NRMRL, US Environmental Protection Agency, Cincinnati, OH, USA.
authors.forename: Christina
authors.initials: C
authors.lastname: Bennett-Stamper
mesh_terms: D000327:Adsorption; D018441:Biofilms; D002563:Cerium / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D020102:Mycobacterium smegmatis / Q000502:physiology*; D053758:Nanoparticles / Q000737:chemistry*; D011551:Pseudomonas fluorescens / Q000502:physiology*
chemical_list: D002563:Cerium; C030583:ceric oxide
keywords: Confocal laser microscopy; Microbial biofilm; Nano-CeO(2); Nanoparticles; Sorption kinetics