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

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 a10−3 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 × 10−5 M to 8.0 × 10−4 M with a limit of detection of 1.47 × 10−5 M and accuracy of 7.9% for 9.0 × 10−5 M and 14.1% for 2.0 × 10−4 M, (n = 5). Satisfactory results were obtained for cholesterol determination in serum samples compared to a reference procedure.