Electrochemiluminescent disposable cholesterol biosensor based on avidin-biotin assembling with the electroformed luminescent conducting polymer poly(luminol-biotinylated pyrrole)

An electrochemiluminescent cholesterol disposable biosensor has been prepared by the formation of assembled layers on gold screen-printed cells. The detection layer is based on the electro-formation of new luminol copolymers with different synthesized biotinylated pyrroles prepared by click-chemistry, offering a new transduction layer with new electroluminescent properties on biosensors. The electrochemiluminescence (ECL) luminol copolymers are electroformed by cyclic voltammetry (five cycles) at pH 7.0 uses a 10(-3) M biotinylated pyrrole-luminol ratio of 1:10 in PBS buffer. With respect to the recognition layer, cholesterol oxidase was biotinylated by incubation with biotin vinyl sulfone, and immobilized on the copolymer by avidin-biotin interaction. The analytical signal of the biosensor is the ECL enzymatic initial rate working in chronoamperometric mode at 0.5 V excitation potential with 10 s between pulses at pH 9.5. The disposable device offers a cholesterol linear range from 1.5 x 10(-5) M to 8.0 x 10(-4) M with a limit of detection of 1.47 x 10(-5) M and accuracy of 7.9% for 9.0 x 10(-5) M and 14.1% for 2.0 x 10(-4) M, (n = 5). Satisfactory results were obtained for cholesterol determination in serum samples compared to a reference procedure. (C) 2012 Elsevier B.V. All rights reserved.