ng/ml-Level Alpha-Fetoprotein Immuno-Detection with Torsion-Mode Cantilever Sensors for Early-Stage Heptocellular Carcinoma Diagnosis

We present a silicon micromechanical sensor with the resonance exciting and signal pickup elements monolithic integrated for screening tumor markers. By measuring frequency-shift versus specific-adsorbed mass, anti-alpha-fetoprotein (AFP) is detected by the resonant immuno-sensor sensitized with AFP antibody based on specific antigen-antibody interaction. The torsion-mode resonant cantilever sensor has the sensitive scale of 2 ng/ml to 200 ng/ml and a ng/mL level detection limit. This indicates that the microcantilever sensor is suitable for tumor marker detection, e.g. for screening heptocellular carcinoma (HCC). Considering that the ultra-sensitive biosensor is fit for application in on- the-spot portable or even disposable biomedical detection, the micromechanical sensing cantilever with a label-free technology is promising for disease early-stage prognosis and diagnosis.