title: Exploitation of S-layer anisotropy: pH-dependent nanolayer orientation for cellular micropatterning.
abstract: We have developed a tunable, facile, and reliable cell patterning method using a self-assembled crystalline protein monolayer that, depending on its orientation, can exhibit either cell adhesive (cytophilic) or cell repulsive (cytophobic) surface properties. Our technique exploits, for the first time, the inherent biological anisotropy of the bacterial cell wall protein SbpA capable of interacting with its cytophilic inner side with components of the cell wall, while its outer cytophobic side interacts with the environment. By simply altering the recrystallization protocol from a basic to an acidic condition, the SbpA-protein layer orientation and function can be switched from preventing unspecific protein adsorption and cell adhesion to effectively promote cell attachment, spreading, and proliferation. As a result, the same protein solution can be used to form cell adhesive and repulsive regions over large areas on a single substrate using a simple pH-dependent self-assembly procedure. The reliable establishment of cytophobic and cytophilic SbpA layers allows the generation of well-defined surface patterns that exhibit uniform height (9-10 nm), p4 lattice symmetry with center-to-center spacing of the morphological units of 12 nm, as well as similar surface potential and charge distributions under cell culture conditions. The pH-dependent "orientation switch" of the SbpA protein nanolayer was integrated with micromolding in capillaries (MIMIC) technology to demonstrate its application for cell patterning using a variety of cell lines including epithelial, fibroblast and endothelial cells.
authors.affiliation: Institute for Biophysics, Department of Nanobiotechnology, ‡Institute for Synthetic Bioarchitectures, Department of Nanobiotechnology, †BioSensor Technologies, Austrian Institute of Technology (AIT), University of Natural Resources and Life Science , Muthgasse 11, Vienna 1190, Austria.
authors.forename: Mario
authors.initials: M
authors.lastname: Rothbauer
authors.forename: Seta
authors.initials: S
authors.lastname: Küpcü
authors.forename: Drago
authors.initials: D
authors.lastname: Sticker
authors.forename: Uwe B
authors.initials: UB
authors.lastname: Sleytr
authors.forename: Peter
authors.initials: P
authors.lastname: Ertl
mesh_terms: D000327:Adsorption; D016880:Anisotropy; D001426:Bacterial Proteins / Q000737:chemistry* / Q000493:pharmacokinetics*; D018938:Caco-2 Cells; D002448:Cell Adhesion / Q000502:physiology*; D018929:Cell Culture Techniques / Q000379:methods*; D002469:Cell Separation / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis / Q000493:pharmacokinetics; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008968:Molecular Conformation; D054802:Molecular Imprinting / Q000379:methods*; D009004:Monosaccharide Transport Proteins / Q000737:chemistry* / Q000493:pharmacokinetics*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D011485:Protein Binding; D055672:Static Electricity; D013499:Surface Properties
chemical_list: D001426:Bacterial Proteins; D020099:Coated Materials, Biocompatible; D009004:Monosaccharide Transport Proteins; C120455:SbpA protein, bacteria