title: Detection of inducible nitric oxide synthase using a suite of electrochemical, fluorescence, and surface plasmon resonance biosensors.
abstract: A suite of biosensors for rapid detection of inducible nitric oxide synthase (iNOS) is described. First, a metal-enhanced electrochemical detection (MED) sensor, which relied on the redox properties of a silver monolayer, was developed. The linear detection range was between 8.64×10(-2) and 5.4×10(1)ng/ml with a detection limit of 1.69×10(-4)ng/ml. This method was compared with surface plasmon resonance (SPR) biosensors in which polyclonal mouse anti-iNOS was covalently immobilized onto a gold surface using an iNOS antigen. The linear detection range recorded was between 3.37×10(1) and 5.4×10(-2)ng/ml with a detection limit of 2×10(-3)ng/ml. Finally, an ultrasensitive portable capillary (UPAC) fluorescence immunosensor, in which a mouse anti-iNOS antibody was covalently immobilized onto the inner surface of a capillary and a rabbit anti-iNOS antibody was employed as the secondary antibody, was developed. The resulting signals were found to be directly proportional to iNOS concentrations between 1.52×10(-1) and 1.52×10(-2)ng/ml with a detection limit of 1.05×10(-3)ng/ml. These immunosensors exhibit low cross-reactivity toward potential interferents such as human serum albumin and ovalbumin. The SPR and UPAC biosensors were validated using simulated blood spiked with recombinant iNOS, resulting in recoveries of 85% and 88.5%, respectively. The research presented in this article could potentially provide new ways of detecting NO for diagnostic and biomarker purposes in medical research.
authors.affiliation: Center for Advanced Sensors and Environmental Systems (CASE), Department of Chemistry, State University of New York at Binghamton, Binghamton, NY 13902, USA.
authors.forename: Naumih M
authors.initials: NM
authors.lastname: Noah
authors.forename: Saamia
authors.initials: S
authors.lastname: Alam
authors.forename: Omowunmi A
authors.initials: OA
authors.lastname: Sadik
mesh_terms: D000818:Animals; D001802:Blood Substitutes / Q000737:chemistry; D002138:Calibration; D055664:Electrochemical Techniques / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods; D006801:Humans; D057230:Limit of Detection; D052247:Nitric Oxide Synthase Type II / Q000032:analysis*; D010084:Oxidation-Reduction; D012834:Silver / Q000737:chemistry; D020349:Surface Plasmon Resonance
chemical_list: D001802:Blood Substitutes; D012834:Silver; D052247:Nitric Oxide Synthase Type II