Extracellular polymeric substances (EPS) of freshwater biofilms stabilize and modify CeO2 and Ag nanoparticles
Streams are potential receiving compartments for engineered nanoparticles (NP). In streams, NP may remain dispersed or settle to the benthic compartment. Both dispersed and settling NP can accumulate in benthic biofilms called periphyton that are essential to stream ecosystems. Periphytic organisms...
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| description | Streams are potential receiving compartments for engineered nanoparticles (NP). In streams, NP may remain dispersed or settle to the benthic compartment. Both dispersed and settling NP can accumulate in benthic biofilms called periphyton that are essential to stream ecosystems. Periphytic organisms excrete extracellular polymeric substances (EPS) that interact with any material reaching the biofilms. To understand the interaction of NP with periphyton it is therefore crucial to study the interaction of NP with EPS. We investigated the influence of EPS on the physicochemical properties of selected NP (CeO2, Ag) under controlled conditions at pH 6, 7.6, 8.6 and light or dark exposure. We extracted EPS from five different periphyton communities, characterized the extracts, and exposed CeO2 and carbonate-stabilized Ag NP (0.5 and 5 mg/L, both 25 nm primary particle size) and AgNO3 to EPS (10 mg/L) over two weeks. We measured NP size distribution, shape, primary particle size, surface plasmon resonance, and dissolution. All EPS extracts were composed of biopolymers, building blocks of humic substances, low molecular weight (Mr) acids, and small amphiphilic or neutral compounds in varying concentrations. CeO2 NP were stabilized by EPS independent of pH and light/dark while dissolution increased over time in the dark at pH 6. EPS induced a size increase in Ag NP in the light with decreasing pH and the formation of metallic Ag NP from AgNO3 at the same conditions via EPS-enhanced photoreduction. NP transformation and formation were slower in the extract with the lowest biopolymer and low Mr acid concentrations. Periphytic EPS in combination with naturally varying pH and light/dark conditions influence the properties of the Ag and CeO2 NP tested and thus the exposure conditions within biofilms. Our results indicate that periphytic organisms may be exposed to a constantly changing mixture of engineered and naturally formed Ag NP and Ag+. |
| doi_str_mv | 10.1371/journal.pone.0110709 |
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In streams, NP may remain dispersed or settle to the benthic compartment. Both dispersed and settling NP can accumulate in benthic biofilms called periphyton that are essential to stream ecosystems. Periphytic organisms excrete extracellular polymeric substances (EPS) that interact with any material reaching the biofilms. To understand the interaction of NP with periphyton it is therefore crucial to study the interaction of NP with EPS. We investigated the influence of EPS on the physicochemical properties of selected NP (CeO2, Ag) under controlled conditions at pH 6, 7.6, 8.6 and light or dark exposure. We extracted EPS from five different periphyton communities, characterized the extracts, and exposed CeO2 and carbonate-stabilized Ag NP (0.5 and 5 mg/L, both 25 nm primary particle size) and AgNO3 to EPS (10 mg/L) over two weeks. We measured NP size distribution, shape, primary particle size, surface plasmon resonance, and dissolution. All EPS extracts were composed of biopolymers, building blocks of humic substances, low molecular weight (Mr) acids, and small amphiphilic or neutral compounds in varying concentrations. CeO2 NP were stabilized by EPS independent of pH and light/dark while dissolution increased over time in the dark at pH 6. EPS induced a size increase in Ag NP in the light with decreasing pH and the formation of metallic Ag NP from AgNO3 at the same conditions via EPS-enhanced photoreduction. NP transformation and formation were slower in the extract with the lowest biopolymer and low Mr acid concentrations. Periphytic EPS in combination with naturally varying pH and light/dark conditions influence the properties of the Ag and CeO2 NP tested and thus the exposure conditions within biofilms. Our results indicate that periphytic organisms may be exposed to a constantly changing mixture of engineered and naturally formed Ag NP and Ag+.</description><identifier>ISSN: 1932-6203</identifier><identifier>EISSN: 1932-6203</identifier><identifier>DOI: 10.1371/journal.pone.0110709</identifier><identifier>PMID: 25333364</identifier><language>eng</language><publisher>United States: Public Library of Science</publisher><subject>Acids ; Aquatic ecosystems ; Aquatic sciences ; Biofilms ; Biology and Life Sciences ; Biopolymers ; Biopolymers - chemistry ; Carbonates ; Cerium oxides ; Chemistry ; Controlled conditions ; Cytotoxicity ; Dissolution ; Earth Sciences ; Ecology and Environmental Sciences ; Engineering and Technology ; Environmental changes ; Environmental science ; Exposure ; Fresh Water ; Humic acids ; Hydrogen ions ; Low molecular weights ; Metal Nanoparticles - chemistry ; Molecular weight ; Nanoparticles ; Oxidation ; Particle size ; Particle size distribution ; Periphyton ; pH effects ; Photochemistry ; Photoreduction ; Physical Sciences ; Physicochemical properties ; Polymethyl methacrylate ; Silver ; Silver - chemistry ; Size distribution ; Streams ; Surface plasmon resonance ; Toxicology ; Transformation</subject><ispartof>PloS one, 2014-10, Vol.9 (10), p.e110709</ispartof><rights>2014 Kroll et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License: http://creativecommons.org/licenses/by/4.0/ (the “License”), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.</rights><rights>2014 Kroll et al 2014 Kroll et al</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c592t-b204f6632a768cb6e827c6ea9db9e1a28913fec0b5b839c526d2837ed59ee2d13</citedby><cites>FETCH-LOGICAL-c592t-b204f6632a768cb6e827c6ea9db9e1a28913fec0b5b839c526d2837ed59ee2d13</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4204993/pdf/$$EPDF$$P50$$Gpubmedcentral$$Hfree_for_read</linktopdf><linktohtml>$$Uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4204993/$$EHTML$$P50$$Gpubmedcentral$$Hfree_for_read</linktohtml><link.rule.ids>230,314,723,776,780,860,881,2096,2915,23845,27901,27902,53766,53768,79342,79343</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/25333364$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Kroll, Alexandra</creatorcontrib><creatorcontrib>Behra, Renata</creatorcontrib><creatorcontrib>Kaegi, Ralf</creatorcontrib><creatorcontrib>Sigg, Laura</creatorcontrib><title>Extracellular polymeric substances (EPS) of freshwater biofilms stabilize and modify CeO2 and Ag nanoparticles</title><title>PloS one</title><addtitle>PLoS One</addtitle><description>Streams are potential receiving compartments for engineered nanoparticles (NP). In streams, NP may remain dispersed or settle to the benthic compartment. Both dispersed and settling NP can accumulate in benthic biofilms called periphyton that are essential to stream ecosystems. Periphytic organisms excrete extracellular polymeric substances (EPS) that interact with any material reaching the biofilms. To understand the interaction of NP with periphyton it is therefore crucial to study the interaction of NP with EPS. We investigated the influence of EPS on the physicochemical properties of selected NP (CeO2, Ag) under controlled conditions at pH 6, 7.6, 8.6 and light or dark exposure. We extracted EPS from five different periphyton communities, characterized the extracts, and exposed CeO2 and carbonate-stabilized Ag NP (0.5 and 5 mg/L, both 25 nm primary particle size) and AgNO3 to EPS (10 mg/L) over two weeks. We measured NP size distribution, shape, primary particle size, surface plasmon resonance, and dissolution. All EPS extracts were composed of biopolymers, building blocks of humic substances, low molecular weight (Mr) acids, and small amphiphilic or neutral compounds in varying concentrations. CeO2 NP were stabilized by EPS independent of pH and light/dark while dissolution increased over time in the dark at pH 6. EPS induced a size increase in Ag NP in the light with decreasing pH and the formation of metallic Ag NP from AgNO3 at the same conditions via EPS-enhanced photoreduction. NP transformation and formation were slower in the extract with the lowest biopolymer and low Mr acid concentrations. Periphytic EPS in combination with naturally varying pH and light/dark conditions influence the properties of the Ag and CeO2 NP tested and thus the exposure conditions within biofilms. Our results indicate that periphytic organisms may be exposed to a constantly changing mixture of engineered and naturally formed Ag NP and Ag+.</description><subject>Acids</subject><subject>Aquatic ecosystems</subject><subject>Aquatic sciences</subject><subject>Biofilms</subject><subject>Biology and Life Sciences</subject><subject>Biopolymers</subject><subject>Biopolymers - chemistry</subject><subject>Carbonates</subject><subject>Cerium oxides</subject><subject>Chemistry</subject><subject>Controlled conditions</subject><subject>Cytotoxicity</subject><subject>Dissolution</subject><subject>Earth Sciences</subject><subject>Ecology and Environmental Sciences</subject><subject>Engineering and Technology</subject><subject>Environmental changes</subject><subject>Environmental science</subject><subject>Exposure</subject><subject>Fresh Water</subject><subject>Humic acids</subject><subject>Hydrogen ions</subject><subject>Low molecular weights</subject><subject>Metal Nanoparticles - chemistry</subject><subject>Molecular weight</subject><subject>Nanoparticles</subject><subject>Oxidation</subject><subject>Particle size</subject><subject>Particle size distribution</subject><subject>Periphyton</subject><subject>pH effects</subject><subject>Photochemistry</subject><subject>Photoreduction</subject><subject>Physical Sciences</subject><subject>Physicochemical properties</subject><subject>Polymethyl methacrylate</subject><subject>Silver</subject><subject>Silver - chemistry</subject><subject>Size distribution</subject><subject>Streams</subject><subject>Surface plasmon resonance</subject><subject>Toxicology</subject><subject>Transformation</subject><issn>1932-6203</issn><issn>1932-6203</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2014</creationdate><recordtype>article</recordtype><sourceid>EIF</sourceid><sourceid>BENPR</sourceid><sourceid>DOA</sourceid><recordid>eNp1Uk1v1DAUjBCIlsI_QGCJS3vYxR-JE18qVauFVqpUJNqz5Y_nrVdOHOwE2P560m5atQd8sZ89M2_8NEXxkeAlYTX5uo1j6lRY9rGDJSYE11i8Kg6JYHTBKWavn50Pinc5bzGuWMP52-KAVmxavDwsuvXfISkDIYxBJdTHsGsheYPyqPOgOgMZHa9__DxB0SGXIN_-UQMkpH10PrQZTSDtg78DpDqL2mi926EVXNGH-myDOtXFXqXBmwD5ffHGqZDhw7wfFTff1ter88Xl1feL1dnlwlSCDgtNcek4Z1TVvDGaQ0Nrw0EJqwUQRRtBmAODdaUbJkxFuaUNq8FWAoBawo6Kz3vdPsQs51FlSTipai54QyfExR5ho9rKPvlWpZ2MysuHi5g2cjYtWUUYUzVoh0VJiVWGacec5Q2pRGnMpHU6dxt1C9ZAN800vBB9-dL5W7mJv2U5_VMINgl8mQVS_DVCHv5judyjTIo5J3BPHQiW95l4ZMn7TMg5ExPt03N3T6THELB_6GW22A</recordid><startdate>20141021</startdate><enddate>20141021</enddate><creator>Kroll, Alexandra</creator><creator>Behra, Renata</creator><creator>Kaegi, Ralf</creator><creator>Sigg, Laura</creator><general>Public Library of Science</general><general>Public Library of Science (PLoS)</general><scope>CGR</scope><scope>CUY</scope><scope>CVF</scope><scope>ECM</scope><scope>EIF</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>3V.</scope><scope>7QG</scope><scope>7QL</scope><scope>7QO</scope><scope>7RV</scope><scope>7SN</scope><scope>7SS</scope><scope>7T5</scope><scope>7TG</scope><scope>7TM</scope><scope>7U9</scope><scope>7X2</scope><scope>7X7</scope><scope>7XB</scope><scope>88E</scope><scope>8AO</scope><scope>8C1</scope><scope>8FD</scope><scope>8FE</scope><scope>8FG</scope><scope>8FH</scope><scope>8FI</scope><scope>8FJ</scope><scope>8FK</scope><scope>ABJCF</scope><scope>ABUWG</scope><scope>AEUYN</scope><scope>AFKRA</scope><scope>ARAPS</scope><scope>ATCPS</scope><scope>AZQEC</scope><scope>BBNVY</scope><scope>BENPR</scope><scope>BGLVJ</scope><scope>BHPHI</scope><scope>C1K</scope><scope>CCPQU</scope><scope>D1I</scope><scope>DWQXO</scope><scope>FR3</scope><scope>FYUFA</scope><scope>GHDGH</scope><scope>GNUQQ</scope><scope>H94</scope><scope>HCIFZ</scope><scope>K9.</scope><scope>KB.</scope><scope>KB0</scope><scope>KL.</scope><scope>L6V</scope><scope>LK8</scope><scope>M0K</scope><scope>M0S</scope><scope>M1P</scope><scope>M7N</scope><scope>M7P</scope><scope>M7S</scope><scope>NAPCQ</scope><scope>P5Z</scope><scope>P62</scope><scope>P64</scope><scope>PATMY</scope><scope>PDBOC</scope><scope>PIMPY</scope><scope>PQEST</scope><scope>PQQKQ</scope><scope>PQUKI</scope><scope>PTHSS</scope><scope>PYCSY</scope><scope>RC3</scope><scope>5PM</scope><scope>DOA</scope></search><sort><creationdate>20141021</creationdate><title>Extracellular polymeric substances (EPS) of freshwater biofilms stabilize and modify CeO2 and Ag nanoparticles</title><author>Kroll, Alexandra ; Behra, Renata ; Kaegi, Ralf ; Sigg, Laura</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c592t-b204f6632a768cb6e827c6ea9db9e1a28913fec0b5b839c526d2837ed59ee2d13</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2014</creationdate><topic>Acids</topic><topic>Aquatic ecosystems</topic><topic>Aquatic sciences</topic><topic>Biofilms</topic><topic>Biology and Life Sciences</topic><topic>Biopolymers</topic><topic>Biopolymers - chemistry</topic><topic>Carbonates</topic><topic>Cerium oxides</topic><topic>Chemistry</topic><topic>Controlled conditions</topic><topic>Cytotoxicity</topic><topic>Dissolution</topic><topic>Earth Sciences</topic><topic>Ecology and Environmental Sciences</topic><topic>Engineering and Technology</topic><topic>Environmental changes</topic><topic>Environmental science</topic><topic>Exposure</topic><topic>Fresh Water</topic><topic>Humic acids</topic><topic>Hydrogen ions</topic><topic>Low molecular weights</topic><topic>Metal Nanoparticles - chemistry</topic><topic>Molecular weight</topic><topic>Nanoparticles</topic><topic>Oxidation</topic><topic>Particle size</topic><topic>Particle size distribution</topic><topic>Periphyton</topic><topic>pH effects</topic><topic>Photochemistry</topic><topic>Photoreduction</topic><topic>Physical Sciences</topic><topic>Physicochemical properties</topic><topic>Polymethyl methacrylate</topic><topic>Silver</topic><topic>Silver - chemistry</topic><topic>Size distribution</topic><topic>Streams</topic><topic>Surface plasmon resonance</topic><topic>Toxicology</topic><topic>Transformation</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Kroll, Alexandra</creatorcontrib><creatorcontrib>Behra, Renata</creatorcontrib><creatorcontrib>Kaegi, Ralf</creatorcontrib><creatorcontrib>Sigg, Laura</creatorcontrib><collection>Medline</collection><collection>MEDLINE</collection><collection>MEDLINE (Ovid)</collection><collection>MEDLINE</collection><collection>MEDLINE</collection><collection>PubMed</collection><collection>CrossRef</collection><collection>ProQuest Central (Corporate)</collection><collection>Animal Behavior Abstracts</collection><collection>Bacteriology Abstracts (Microbiology B)</collection><collection>Biotechnology Research Abstracts</collection><collection>Nursing & Allied Health Database</collection><collection>Ecology Abstracts</collection><collection>Entomology Abstracts (Full archive)</collection><collection>Immunology Abstracts</collection><collection>Meteorological & Geoastrophysical Abstracts</collection><collection>Nucleic Acids Abstracts</collection><collection>Virology and AIDS Abstracts</collection><collection>Agricultural Science Collection</collection><collection>Health & Medical Collection</collection><collection>ProQuest Central (purchase pre-March 2016)</collection><collection>Medical Database (Alumni Edition)</collection><collection>ProQuest Pharma Collection</collection><collection>Public Health Database</collection><collection>Technology Research Database</collection><collection>ProQuest SciTech Collection</collection><collection>ProQuest Technology Collection</collection><collection>ProQuest Natural Science Collection</collection><collection>Hospital Premium Collection</collection><collection>Hospital Premium Collection (Alumni Edition)</collection><collection>ProQuest Central (Alumni) (purchase pre-March 2016)</collection><collection>Materials Science & Engineering Collection</collection><collection>ProQuest Central (Alumni Edition)</collection><collection>ProQuest One Sustainability</collection><collection>ProQuest Central UK/Ireland</collection><collection>Advanced Technologies & Aerospace Collection</collection><collection>Agricultural & Environmental Science Collection</collection><collection>ProQuest Central Essentials</collection><collection>Biological Science Collection</collection><collection>ProQuest Central</collection><collection>Technology Collection</collection><collection>Natural Science Collection</collection><collection>Environmental Sciences and Pollution Management</collection><collection>ProQuest One Community College</collection><collection>ProQuest Materials Science Collection</collection><collection>ProQuest Central Korea</collection><collection>Engineering Research Database</collection><collection>Health Research Premium Collection</collection><collection>Health Research Premium Collection (Alumni)</collection><collection>ProQuest Central Student</collection><collection>AIDS and Cancer Research Abstracts</collection><collection>SciTech Premium Collection</collection><collection>ProQuest Health & Medical Complete (Alumni)</collection><collection>Materials Science Database</collection><collection>Nursing & Allied Health Database (Alumni Edition)</collection><collection>Meteorological & Geoastrophysical Abstracts - 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In streams, NP may remain dispersed or settle to the benthic compartment. Both dispersed and settling NP can accumulate in benthic biofilms called periphyton that are essential to stream ecosystems. Periphytic organisms excrete extracellular polymeric substances (EPS) that interact with any material reaching the biofilms. To understand the interaction of NP with periphyton it is therefore crucial to study the interaction of NP with EPS. We investigated the influence of EPS on the physicochemical properties of selected NP (CeO2, Ag) under controlled conditions at pH 6, 7.6, 8.6 and light or dark exposure. We extracted EPS from five different periphyton communities, characterized the extracts, and exposed CeO2 and carbonate-stabilized Ag NP (0.5 and 5 mg/L, both 25 nm primary particle size) and AgNO3 to EPS (10 mg/L) over two weeks. We measured NP size distribution, shape, primary particle size, surface plasmon resonance, and dissolution. All EPS extracts were composed of biopolymers, building blocks of humic substances, low molecular weight (Mr) acids, and small amphiphilic or neutral compounds in varying concentrations. CeO2 NP were stabilized by EPS independent of pH and light/dark while dissolution increased over time in the dark at pH 6. EPS induced a size increase in Ag NP in the light with decreasing pH and the formation of metallic Ag NP from AgNO3 at the same conditions via EPS-enhanced photoreduction. NP transformation and formation were slower in the extract with the lowest biopolymer and low Mr acid concentrations. Periphytic EPS in combination with naturally varying pH and light/dark conditions influence the properties of the Ag and CeO2 NP tested and thus the exposure conditions within biofilms. Our results indicate that periphytic organisms may be exposed to a constantly changing mixture of engineered and naturally formed Ag NP and Ag+.</abstract><cop>United States</cop><pub>Public Library of Science</pub><pmid>25333364</pmid><doi>10.1371/journal.pone.0110709</doi><oa>free_for_read</oa></addata></record> |
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| subjects | Acids Aquatic ecosystems Aquatic sciences Biofilms Biology and Life Sciences Biopolymers Biopolymers - chemistry Carbonates Cerium oxides Chemistry Controlled conditions Cytotoxicity Dissolution Earth Sciences Ecology and Environmental Sciences Engineering and Technology Environmental changes Environmental science Exposure Fresh Water Humic acids Hydrogen ions Low molecular weights Metal Nanoparticles - chemistry Molecular weight Nanoparticles Oxidation Particle size Particle size distribution Periphyton pH effects Photochemistry Photoreduction Physical Sciences Physicochemical properties Polymethyl methacrylate Silver Silver - chemistry Size distribution Streams Surface plasmon resonance Toxicology Transformation |
| title | Extracellular polymeric substances (EPS) of freshwater biofilms stabilize and modify CeO2 and Ag nanoparticles |
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