Detection of a BSA-Biotin-Conjugate by a Novel Immunosensor

We describe a new kind of biosensor for the electro-magnetic sensing of analytes such as antibodies. In the present study the molecules bovine serum albumin (BSA) and the corresponding antibody (Anti-BSA) as well as biotin and NeutrAvidin are used as model systems. The analyte molecules are labelled with superparamagnetic microbeads and detected by sensor transducers with biofunctionalised microelectrodes. It is shown that a carboxyl-modified dextran (CMD) layer is well suited as an immobilization matrix for ligands on the microelectrode surface. The CMD layer offers a suitable and stable surface for binding of the antibodies and also suppresses unspecific binding of protein/antibody coated microbeads to the electroactive platinum surface