title: Engineered nanopore of Phi29 DNA-packaging motor for real-time detection of single colon cancer specific antibody in serum.
abstract: The ingenious design of the bacterial virus phi29 DNA packaging nanomotor with an elegant and elaborate channel has inspired its application for single molecule detection of antigen/antibody interactions. The hub of this bacterial virus nanomotor is a truncated cone-shaped connector consisting of 12 protein subunits. These subunits form a ring with a central 3.6-nm channel acting as a path for dsDNA to enter during packaging and to exit during infection. The connector has been inserted into a lipid bilayer. Herein, we reengineered an Epithelial Cell Adhesion Molecule (EpCAM) peptide into the C-terminal of nanopore as a probe to specifically detect EpCAM antibody (Ab) in nanomolar concentration at the single molecule level. The binding of Abs sequentially to each peptide probe induced stepwise blocks in current. The distinctive current signatures enabled us to analyze the docking and undocking kinetics of Ab-probe interactions and determine the Kd. The signal of EpCAM antibody can be discriminated from the background events in the presence of nonspecific antibody or serum. Our results demonstrate the feasibility of generating a highly sensitive platform for detecting antibodies at extremely low concentrations in the presence of contaminants.
authors.affiliation: Nanobiotechnology Center, ‡Department of Pharmaceutical Sciences, College of Pharmacy, and §Markey Cancer Center, University of Kentucky , Lexington, Kentucky 40536, United States.
authors.forename: Shaoying
authors.initials: S
authors.lastname: Wang
authors.forename: Farzin
authors.initials: F
authors.lastname: Haque
authors.forename: Piotr G
authors.initials: PG
authors.lastname: Rychahou
authors.forename: B Mark
authors.initials: BM
authors.lastname: Evers
authors.forename: Peixuan
authors.initials: P
authors.lastname: Guo
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry*; D000951:Antigens, Neoplasm / Q000737:chemistry; D017103:Bacillus Phages / Q000737:chemistry*; D014408:Biomarkers, Tumor; D015815:Cell Adhesion Molecules / Q000737:chemistry; D003110:Colonic Neoplasms / Q000097:blood* / Q000276:immunology*; D042003:DNA Packaging; D004279:DNA, Viral / Q000378:metabolism; D004566:Electrodes; D000071858:Epithelial Cell Adhesion Molecule; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry; D008297:Male; D051379:Mice; D008819:Mice, Nude; D053758:Nanoparticles; D058608:Nanopores; D036103:Nanotechnology; D010455:Peptides / Q000737:chemistry; D017434:Protein Structure, Tertiary
chemical_list: D000906:Antibodies; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D015815:Cell Adhesion Molecules; D004279:DNA, Viral; D000071858:Epithelial Cell Adhesion Molecule; D008051:Lipid Bilayers; D010455:Peptides