title: Hydrogel-coated streptavidin piezoelectric biosensors and applications to selective detection of Strep-tag displaying cells.
abstract: Two different hydrogel-coated streptavidin (SAv) piezoelectric chips were investigated. One was directly prepared by immobilizing SAv molecules covalently onto a dextran-modified crystal, and the other one was indirectly prepared by physically adsorbing SAv onto a biotin-linked dextran surface. The covalent preparation yielded 80% more SAv-binding and better subsequent adsorption of biotinylated bovine serum albumin (bBSA). Both chips displayed the best binding affinity with bBSA at pH 5.0 in a flow injection analysis and exhibited reproductive real-time response during layer-by-layer assembly of a bBSA and SAv multilayer film. In the multilayer assembly, approximately 3-7 SAv molecules were captured by each immobilized bBSA, and the estimated apparent KD values of the binding of flowing bBSA with surface SAv were 0.24 and 0.11 microM in the first two cycles of the covalently prepared chip, respectively. Two Escherichia coli cells, each flagellum-displaying Strep-tag I and Strep-tag II, respectively, were selectively detected by both kinds of SAv chips. These studies suggest the potential application of both chips in real-time screening SAv affinity ligands from a cell-display random peptide library.
authors.affiliation: Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
authors.forename: Hsiu-Mei
authors.initials: HM
authors.lastname: Chen
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Lin
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D019921:Biotinylation; D002417:Cattle; D003911:Dextrans / Q000737:chemistry; D004926:Escherichia coli / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000378:metabolism; D019809:Streptavidin / Q000737:chemistry*
chemical_list: D003911:Dextrans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D012710:Serum Albumin, Bovine; D019809:Streptavidin