title: Recrystallization of bacterial S-layers on flat polyelectrolyte surfaces and hollow polyelectrolyte capsules.
abstract: Polyelectrolyte multilayer (PE) deposition and S-layer technology have been combined to make novel robust biomimetic surfaces and membranes. Isolated subunits of the bacterial cell surface layer from Bacillus sphaericus CCM2177 SbpA was self-assembled on PE multilayer supports, with the composition of the multilayer playing a crucial role in determining the structure of the resulting supported protein layers. Flat substrates were studied using atomic force microscopy and neutron reflectometry; protein on suitable PE combinations showed a crystalline structure with lattice constants equal to those found in vivo on bacterial surfaces. The mechanical stability of the S-layer is higher when recrystallized on PEs than directly on silicon supports. The recrystallization process was subsequently used to coat colloidal particles, permitting the determination of zeta potentials before and after coating. Hollow capsules could also be coated in the same way, as proven by various techniques. Our results suggest that electrostatic interactions via divalent cations are important for the assembly process. The results also demonstrate that the versatility of the PE multilayer membranes can be successfully combined with the well-defined surface chemistry and structure of 2D protein crystals.
authors.affiliation: Rovira i Virgili University, Department of Chemical Engineering, Campus Sescelades, Av. Paisos Catalans 26, 43007 Tarragona, Spain. jltoca@etseq.urv.es
authors.forename: José Luis
authors.initials: JL
authors.lastname: Toca-Herrera
authors.forename: Rumen
authors.initials: R
authors.lastname: Krastev
authors.forename: Vera
authors.initials: V
authors.lastname: Bosio
authors.forename: Seta
authors.initials: S
authors.lastname: Küpcü
authors.forename: Dietmar
authors.initials: D
authors.lastname: Pum
authors.forename: Andreas
authors.initials: A
authors.lastname: Fery
authors.forename: Margit
authors.initials: M
authors.lastname: Sára
authors.forename: Uwe B
authors.initials: UB
authors.lastname: Sleytr
mesh_terms: D001407:Bacillus / Q000378:metabolism; D002021:Buffers; D002214:Capsules / Q000737:chemistry; D003460:Crystallization; D004563:Electrochemistry / Q000379:methods; D004573:Electrolytes / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D008956:Models, Chemical; D053769:Nanocapsules / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D011506:Proteins / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry; D013499:Surface Properties
chemical_list: D002021:Buffers; D002214:Capsules; D004573:Electrolytes; D053769:Nanocapsules; D011506:Proteins; D012825:Silicon