title: Characterization of a nanoscale S-layer protein based template for biomolecular patterning.
abstract: Well organized template for biomolecular conjugation is the foundation for biosensing. Most of the current devices are fabricated using lithographic patterning processes and self-assembly monolayer (SAM) methods. However, the research toward developing a sub-10 nm patterned, self-regenerated template on various types of substrates is limited, mainly due to the limited functional groups of the building material. Bacterial surface layer proteins (S-layer proteins) can self-assemble into ordered lattice with regular pore sizes of 2-8 nm on different material supports and interfaces. The ordered structure can regenerate after extreme variations of solvent conditions. In this work, we developed a nanoscale biomolecular template based on S-layer proteins on gold surface for fabrication of sensing layer in biosensors. S-layer proteins were isolated from Bacillus cereus, Lysinibacillus sphaericus and Geobacillus stearothermophilus. Protein concentrations were measured by Bradford assay. The protein purities were verified by SDS-PAGE, showing molecular weights ranging from 97-135 kDa. The hydrophilicity of the substrate surface was measured after surface treatments of protein recrystallization. Atomic force microscopic (AFM) measurement was performed on substrate surface, indicating a successful immobilization of a monolayer of S-layer protein with 8-9 nm height on gold surface. The template can be applied on various material supports and acts as a self-regenerated sensing layer of biosensors in the future.
authors.forename: Wing Sze
authors.initials: WS
authors.lastname: Wong
authors.forename: Pun To
authors.initials: PT
authors.lastname: Yung
mesh_terms: D001407:Bacillus / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods; D003460:Crystallization; D001411:Geobacillus stearothermophilus / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008562:Membrane Glycoproteins / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008970:Molecular Weight; D013499:Surface Properties
chemical_list: D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; C055764:S-layer proteins; D006046:Gold