title: Conjugated gold nanoparticles as a tool for probing the bacterial cell envelope: The case of Shewanella oneidensis MR-1.
abstract: The bacterial cell envelope forms the interface between the interior of the cell and the outer world and is, thus, the means of communication with the environment. In particular, the outer cell surface mediates the adhesion of bacteria to the surface, the first step in biofilm formation. While a number of ligand-based interactions are known for the attachment process in commensal organisms and, as a result, opportunistic pathogens, the process of nonspecific attachment is thought to be mediated by colloidal, physiochemical, interactions. It is becoming clear, however, that colloidal models ignore the heterogeneity of the bacterial surface, and that the so-called nonspecific attachment may be mediated by specific regions of the cell surface, whether or not the relevant interaction is ligand-mediate. The authors introduce surface functionalized gold nanoparticles to probe the surface chemistry of Shewanella oneidensis MR-1 as it relates to surface attachment to ω-substituted alkanethiolates self-assembled monolayers (SAMs). A linear relationship between the attachment of S. oneidensis to SAM modified planar substrates and the number of similarly modified nanoparticles attached to the bacterial surfaces was demonstrated. In addition, the authors demonstrate that carboxylic acid-terminated nanoparticles attach preferentially to the subpolar region of the S. oneidensis and obliteration of that binding preference corresponds in loss of attachment to carboxylic acid terminated SAMs. Moreover, this region corresponds to suspected functional regions of the S. oneidensis surface. Because this method can be employed over large numbers of cells, this method is expected to be generally applicable for understanding cell surface organization across populations.
authors.affiliation: U.S. Army Research Laboratory, Sensors & Electron Devices Directorate, Adelphi, Maryland 20783.
authors.forename: Justin P
authors.initials: JP
authors.lastname: Jahnke
authors.affiliation: Department of Biological Engineering, Center for Microengineered Materials, Center for Biomedical Engineering, The University of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Cornejo
authors.affiliation: U.S. Army Research Laboratory, Sensors & Electron Devices Directorate, Adelphi, Maryland 20783.
authors.forename: James J
authors.initials: JJ
authors.lastname: Sumner
authors.affiliation: Department of Civil Engineering, University of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Schuler
authors.affiliation: Department of Biological Engineering, Center for Microengineered Materials, Center for Biomedical Engineering, The University of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Plamen
authors.initials: P
authors.lastname: Atanassov
authors.affiliation: Department of Biological Engineering, Center for Microengineered Materials, Center for Biomedical Engineering, The University of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Linnea K
authors.initials: LK
authors.lastname: Ista
mesh_terms: D001422:Bacterial Adhesion; D055598:Chemical Phenomena; D006046:Gold / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D020592:Shewanella / Q000737:chemistry* / Q000502:physiology*; D013499:Surface Properties
chemical_list: D006046:Gold