title: Counting of single protein molecules at interfaces and application of this technique in early-stage diagnosis.
abstract: The fluorescence-based detection and counting of single protein molecules after specific binding to antibodies at interfaces is presented. A diode laser was used as the excitation source. The unspecific binding at the interface has been reduced to a level of only 0.1% of the maximum signal level. At present, the detection limit of this molecule-counting process is in the range of 10(-17) mol/L, and the dynamic range of the signal corresponds to 7 orders of magnitude of antigen concentration, but these values are not limiting. As a preliminary application in early-stage diagnosis, we have investigated the detection of a single cardiac actin molecule in human plasma, which is of interest in myocardial infarction diagnosis.
authors.affiliation: Institut für Analytische Chemie, Chemo- und Biosensorik, Universität Regensburg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Löscher
authors.forename: S
authors.initials: S
authors.lastname: Böhme
authors.forename: J
authors.initials: J
authors.lastname: Martin
authors.forename: S
authors.initials: S
authors.lastname: Seeger
mesh_terms: D000199:Actins / Q000097:blood / Q000276:immunology; D000818:Animals; D000906:Antibodies / Q000378:metabolism; D000941:Antigens / Q000032:analysis / Q000378:metabolism; D001798:Blood Proteins / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation / Q000379:methods; D005453:Fluorescence; D006801:Humans; D007834:Lasers; D009203:Myocardial Infarction / Q000175:diagnosis; D011817:Rabbits; D012016:Reference Values
chemical_list: D000199:Actins; D000906:Antibodies; D000941:Antigens; D001798:Blood Proteins