title: Voltammetric immunosensor assembled on carbon-pyrenyl nanostructures for clinical diagnosis of type of diabetes.
abstract: Herein we report the first serum insulin voltammetric immunosensor for diagnosis of type 1 and type 2 diabetic disorders. The sensor is composed of multiwalled carbon nanotube-pyrenebutyric acid frameworks on edge plane pyrolytic graphite electrodes (PGE/MWNT/Py) to which an anti-insulin antibody was covalently attached. The detection of picomolar levels of serum insulin binding to the surface antibody was achieved by monitoring the decrease in voltammetric current signals of a redox probe taken in the electrolyte solution. This method offered a detection limit of 15 pM for free insulin present in serum. This detection limit was further lowered to 5 pM by designing serum insulin conjugates with poly(acrylic acid)-functionalized magnetite nanoparticles (100 nm hydrodynamic diameter) and detecting the binding of MNP-serum insulin conjugate to the surface insulin-antibody on PGE/MWNT/Py electrodes. When tested on real patient serum samples, the sensor accurately measured insulin levels. To our knowledge, this is the first report of a voltammetric immunosensor capable of both diagnosing and distinguishing the type of diabetes based on serum insulin levels in diabetic patients.
authors: Department of Chemistry, Oklahoma State University , Stillwater, Oklahoma 74078, United States.
authors: Vini
authors: V
authors: Singh
authors: Sadagopan
authors: S
authors: Krishnan
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000175:diagnosis*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis*; D004563:Electrochemistry; D004566:Electrodes; D006108:Graphite / Q000737:chemistry; D006801:Humans; D007118:Immunoassay; D007328:Insulin / Q000097:blood* / Q000276:immunology; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D018613:Microscopy, Confocal; D037742:Nanotubes, Carbon; D011721:Pyrenes / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000911:Antibodies, Monoclonal; D007328:Insulin; D058185:Magnetite Nanoparticles; D037742:Nanotubes, Carbon; D011721:Pyrenes; C002218:1-pyrenebutyrate; D002244:Carbon; D006108:Graphite