Surface plasmon resonance biosensor for detection of pregnancy associated plasma protein A2 in clinical samples.

Pregnancy associated plasma protein A2 (PAPP-A2) is a metalloproteinase that plays multiple roles in fetal development and post-natal growth. Here we present a novel surface plasmon resonance (SPR) biosensor for the rapid and quantitative detection of PAPP-A2 in blood samples. This biosensor uses a single surface referencing approach and a sandwich assay with functionalized gold nanoparticles for signal enhancement. We demonstrate that this SPR biosensor enables the detection of PAPP-A2 in 30 % blood plasma at levels as low as 3.6 ng/mL. We also characterize the performance of the biosensor and evaluate its cross-reactivity to a PAPP-A analogue. Finally, we utilize this SPR biosensor for the detection of PAPP-A2 in blood serum from two groups of subjects: pregnant women and healthy non-pregnant women and men. Graphical Abstract Temporal sensor response corresponding to respective steps of the assay for detection of PAPP-A2 in buffer.