Impedance biosensor for peanut protein Ara h 1.
A reagentless electrochemical impedance biosensor for detection of peanut protein Ara h 1, one of the allergenic proteins found in peanuts, has been demonstrated using an Au substrate onto which an antibody film has been immobilized. Following initial stabilization of the self-assembled monolayer (SAM) through which the antibody is immobilized, the biosensor substrate exhibits stable impedance spectra at different stages of substrate preparation. By fitting the impedance spectra to a Randles equivalent circuit, one can demonstrate that the charge-transfer resistance (R(ct)) increases and the differential capacitance (Cd) decreases with increasing concentration of Ara h 1, although R(ct) exhibits greater sensitivity. The detection limit of this reagentless biosensor is estimated to be less than 0.3 nM. Assuming a Langmuir adsorption isotherm, the dissociation constant of the peanut protein Ara h 1 and its antibody can be calculated as 0.52 nM from the variation in differential capacitance with Ara h 1 concentration.
Huang
Yin
Y
Department of Chemical and Biomolecular Engineering and Center for Advanced Materials Processing (CAMP), 8 Clarkson Avenue, Clarkson University, Potsdam, New York 13699-5705, USA.
Bell
Melissa C
MC
Suni
Ian I
II
D000485:Allergens / Q000032:analysis* / Q000276:immunology; D055910:Antibodies, Immobilized / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D052179:Antigens, Plant; D010367:Arachis / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D006023:Glycoproteins / Q000032:analysis* / Q000276:immunology; D008565:Membrane Proteins; D010940:Plant Proteins / Q000032:analysis* / Q000276:immunology; D012680:Sensitivity and Specificity
D000485:Allergens; D055910:Antibodies, Immobilized; D000911:Antibodies, Monoclonal; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins