title: Label-free biosensing with functionalized nanopipette probes.
abstract: Nanopipette technology can uniquely identify biomolecules such as proteins based on differences in size, shape, and electrical charge. These differences are determined by the detection of changes in ionic current as the proteins interact with the nanopipette tip coated with probe molecules. Here we show that electrostatic, biotin-streptavidin, and antibody-antigen interactions on the nanopipette tip surface affect ionic current flowing through a 50-nm pore. Highly charged polymers interacting with the glass surface modulated the rectification property of the nanopipette electrode. Affinity-based binding between the probes tethered to the surface and their target proteins caused a change in the ionic current due to a partial blockade or an altered surface charge. These findings suggest that nanopipettes functionalized with appropriate molecular recognition elements can be used as nanosensors in biomedical and biological research.
authors.affiliation: Department of Biomolecular Engineering, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA.
authors.forename: Senkei
authors.initials: S
authors.lastname: Umehara
authors.forename: Miloslav
authors.initials: M
authors.lastname: Karhanek
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Davis
authors.forename: Nader
authors.initials: N
authors.lastname: Pourmand
mesh_terms: D000818:Animals; D000906:Antibodies; D014408:Biomarkers, Tumor / Q000378:metabolism; D015374:Biosensing Techniques / Q000295:instrumentation*; D001710:Biotin / Q000378:metabolism; D019921:Biotinylation; D002417:Cattle; D004573:Electrolytes; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D005898:Glass; D006801:Humans; D015335:Molecular Probes / Q000378:metabolism*; D049329:Nanostructures; D009363:Neoplasm Proteins / Q000378:metabolism; D015203:Reproducibility of Results; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013194:Staining and Labeling; D055672:Static Electricity; D019809:Streptavidin / Q000378:metabolism; D013499:Surface Properties
chemical_list: D000906:Antibodies; D014408:Biomarkers, Tumor; D004573:Electrolytes; D015335:Molecular Probes; D009363:Neoplasm Proteins; D012710:Serum Albumin, Bovine; D001710:Biotin; D019809:Streptavidin; D016650:Fluorescein-5-isothiocyanate