A new method for the selective determination of laminin-5 concentration using a biosensor and surface plasmon resonance imaging (SPRI) technique is presented. A biosensor based on the specific interaction of laminin-5 with rabbit polyclonal antibody was constructed. The analytically useful dynamic response range of the biosensor is between 0.014 and 0.1 ng mL(-1). The detection limit is 4 pg mL(-1). The potential influence of interferences on the SPRI signal was investigated, and the high selectivity of the biosensor was confirmed. In order to demonstrate the potential application of the biosensor, laminin-5 concentration in blood plasma was determined. The results were compared with the laminin-5 concentration obtained by the commercial enzyme-linked immunosorbent assay (ELISA) kit. A comparison of results from healthy donors obtained by SPRI measurement and ELISA indicates that they are close and shows good agreement with the data reported in the literature. The plasma samples of bladder cancer patients gave higher concentration measured with specific biosensor than by ELISA assay. The study shows the clear difference in concentration of laminin-5 in healthy humans and patients with bladder cancer. Extensive clinical studies using the newly developed method can result in an increase in the use of laminin-5 as a potential cancer marker.
Keywords: Biosensors; Cancer marker; Laminin-5; Surface plasmon resonance imaging.