A Label-Free Detection of Biomolecules Using Micromechanical Biosensors

A Microcantilevers resonator is used to detect a protein biomarker called prostate specific antigen(PSA),which is associated with prostate cancer.Different concentrations of PSA in a buffer solution are detected as a function of deflection of the beams.For this purpose,we use a surface micromachined,antibody-coated polycrystalline silicon micromechanical cantilever beam.Cantilevers have mass sensitivities of the order of 10-17g/Hz,which result from their small mass.This matter allows them to detect an immobilized antibody monolayer corresponding to a mass of about 70fg.With these devices,concentrations as low as 150fg/mL,or 4.5 fM,could be detected from the realistic samples.