Development and application of a miniaturised quartz crystal microbalance (QCM) as immunosensor for bone morphogenetic protein-2

The shift of the resonant frequency caused by mass accumulation and/or change in the surface conditions was detected. For the detection of rhBMP-2 monoclonal anti-human BMP-2 antibodies or the BMPR-IA binding domain (BMPR-IA-Fc) were immobilised on the sensor surface via binding to protein A. Immobilisation of protein A was optimised and controlled via binding of anti-protein A antibodies. The lower detection limit for rhBMP-2 was 0.5 μg/mL (20 nM) using the specific antibody and 2 μg/mL using the receptor domain.