Amperometric DNA biosensor for the determination of auto-antibodies using DNA interaction with Pt(II) complex

A method of denatured DNA immobilisation on cellulose nitrate film has been developed. A modified film of uniform and stable surface has been used as a bio-sensitive part of amperometric DNA biosensor based on the stationary mercury-film covered silver electrode. The biosensor has been used to devise a new variant of solid-phase immumoassay of auto-antibodies (Ab) in blood serum without separation of components. The content of auto-Ab was monitored by measuring the currents of catalytic hydrogen evolution (with potentials of -1.2 and -1.4 V) resulting from the complexing of Pt(II) with DNA or auto-Ab respectively. The determination has been performed within a wide concentration area of 5.0 x 10(-10) to 7.0 x 10(-8) M. The limit of detection is 3.0 x 10(-10) M. The affinity constants for the immunoreaction of DNA-antibodies have been found to be 1.25 x 10(9) and 2.50 x 10(8) M-1, which confirms the specificity of the interaction. The protocol of the immunoassay has been proposed and the procedure of diagnosing Aleutian mink disease (AMD) has been described here. (C) 2003 Elsevier B.V. All rights reserved.