Surface modification of an acoustic biosensor allowing the detection of low concentrations of cancer markers.

Analyte detection with biosensors is strongly influenced by the preparation of the biosensor surface including choice of sensing layers and coupling methods for corresponding capture molecules. We investigated the influence of different coupling procedures, especially considering coupling chemistry and incubation times for reagents, by means of surface acoustic wave (SAW) biosensors. The effect on the signal response was tested in two subsequent protein assays. Our optimized coupling procedure allowed the detection of the breast cancer markers HER-2 (human epidermal growth factor receptor-2) and TIMP-1 (tissue inhibitor of metalloproteinase-1) below the respective clinical cutoff values of only a few nanograms per milliliter.