A SOI-nanowire biosensor for the multiple detection of D-NFATc1 protein in the serum

Abstract

The detection of cancer protein marker D-NFATc1 in the serum with a reusable nanowire (NW) chip based on silicon-on-insulator (SOI) structures was demonstrated. The NW surface was modified with aptamers against D-NFATc1 to attain the biospecific detection of the target protein. Two fabricated NW chip types – with narrow NWs (w = 90 nm) and wide NWs (w = 3 μm) – were compared with respect to their reuse, i.e. the realizability of the repeated detection–regeneration cycles upon D-NFATc1 detection in the serum. The analysis of the serum has shown that the signal obtained with wide NWs was much more stable than that obtained with narrow NWs. This makes the SOI-NW biosensor with wide NWs much more suitable for protein analysis in biological fluids. The signal stability exhibited by the wide NWs allowed for performing repeated detection–regeneration cycles of this chip for multiple detection of D-NFATc1 protein in the serum with 10⁻¹⁴ M sensitivity. Although the narrow NW chip allows for attaining higher sensitivity (with the concentration detection limit DL = 10⁻¹⁵ M), it exhibits much less signal stability upon analysis of multicomponent biological fluids (serum).