title: Control of biofilm formation in water using molecularly capped silver nanoparticles.
abstract: Control of biofouling and its negative effects on process performance of water systems is a serious operational challenge in all of the water sectors. Molecularly capped silver nanoparticles (Ag-MCNPs) were used as a pretreatment strategy for controlling biofilm development in aqueous suspensions using the model organism Pseudomonas aeruginosa. Biofilm control was tested in a two-step procedure: planktonic P. aeruginosa was exposed to the Ag-MCNPs and then the adherent biofilm formed by the surviving cells was monitored by applying a model biofilm-formation assay. Under specific conditions, Ag-MCNPs retarded biofilm formation, even when high percentage of planktonic P. aeruginosa cells survived the treatment. For example, Ag-MCNPs (10 microg mL(-1)) retarded biofilm formation (>60%), when 50 percent of the planktonic P. aeruginosa cells survived the treatment. Moreover, stable low value of relative biomass has been formed in the presence of fixed Ag-MCNPs concentrations at various biofilm incubation times. Our results showed that Ag-MCNPs pretreated cells were able to produce EPS although they succeeded to form relatively low adherent biofilm. These pretreated cells appear well preserved and undamaged under TEM HPH/freeze micrographs, yet the intra cellular material seems to be pushed towards the peripheral parts of the cell, possibly indicating a survival strategy to the presence of Ag-MCNPs. The lower value of relative biomass formed in the presence of Ag-MCNPs could be associated with molecular mechanisms related to biofilm formation or continuous release of silver ions in the sample. However, further research is required to examine these factors.
authors.affiliation: Department of Soil and Water Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Dror-Ehre
authors.forename: A
authors.initials: A
authors.lastname: Adin
authors.forename: G
authors.initials: G
authors.lastname: Markovich
authors.forename: H
authors.initials: H
authors.lastname: Mamane
mesh_terms: D018441:Biofilms; D018533:Biomass; D053758:Nanoparticles; D011550:Pseudomonas aeruginosa / Q000254:growth & development; D012834:Silver / Q000737:chemistry*; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D012834:Silver