title: Characterization of antibacterial polyethersulfone membranes using the Respiration Activity Monitoring System (RAMOS).
abstract: Membranes with antibacterial properties were developed using surface modification of polyethersulfone ultrafiltration membranes. Three different modification strategies using polyelectrolyte layer-by-layer (LbL) technique are described. The first strategy relying on the intrinsic antibacterial properties of poly(diallyldimethylammonium chloride) (PDADMAC) and poly(ethylenimine) (PEI) exhibits only little antibacterial effects. The other two strategies contain silver in both ionic (Ag(+)) and metallic (Ag(0)) form. Ag(+) embedded into negatively charged poly(sodium 4-styrene sulfonate) (PSS) layers totally inhibits bacterial growth. Ag(0) nanoparticles were introduced to the membrane surface by LbL deposition of chitosan- and poly(methacrylic acid) - sodium salt (PMA)-capped silver nanoparticles and subsequent UV or heat treatment. Antibacterial properties of the modified membranes were quantified by a new method based on the Respiration Activity Monitoring System (RAMOS), whereby the oxygen transfer rates (OTR) of E. coli K12 cultures on the membranes were monitored online. As opposed to colony forming counting method RAMOS yields more quantitative and reliable data on the antibacterial effect of membrane modification. Ag-imprinted polyelectrolyte film composed of chitosan (Ag(0))/PMA(Ag(0))/chitosan(Ag(0)) was found to be the most promising among the tested membranes. Further investigation revealed that the concentration and equal distribution of silver in the membrane surface plays an important role in bacterial growth inhibition.
authors.affiliation: Aachener Verfahrenstechnik - Chemical Process Engineering, RWTH Aachen University, Turmstr. 46, 52064 Aachen, Germany. jozef.kochan@avt.rwth-aachen.de
authors.forename: Jozef
authors.initials: J
authors.lastname: Kochan
authors.forename: Marco
authors.initials: M
authors.lastname: Scheidle
authors.forename: Joost
authors.initials: J
authors.lastname: van Erkel
authors.forename: Matías
authors.initials: M
authors.lastname: Bikel
authors.forename: Jochen
authors.initials: J
authors.lastname: Büchs
authors.forename: John Erik
authors.initials: JE
authors.lastname: Wong
authors.forename: Thomas
authors.initials: T
authors.lastname: Melin
authors.forename: Matthias
authors.initials: M
authors.lastname: Wessling
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D015169:Colony Count, Microbial; D004573:Electrolytes / Q000737:chemistry; D048168:Escherichia coli K12; D006358:Hot Temperature; D008567:Membranes, Artificial; D053768:Metal Nanoparticles / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010100:Oxygen / Q000378:metabolism; D056951:Photoelectron Spectroscopy; D011094:Polyethyleneimine / Q000737:chemistry; D011095:Polyethylenes / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D013450:Sulfones / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry; D014462:Ultrafiltration / Q000379:methods*; D014466:Ultraviolet Rays; D018508:Water Purification / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D004573:Electrolytes; D008567:Membranes, Artificial; D011095:Polyethylenes; D011108:Polymers; D000644:Quaternary Ammonium Compounds; D013450:Sulfones; D013451:Sulfonic Acids; C022840:polyether sulfone; C041004:poly-N,N-dimethyl-N,N-diallylammonium chloride; D012834:Silver; D011094:Polyethyleneimine; D010100:Oxygen; C077114:styrenesulfonic acid polymer