A Label-free Detection of Carcinoembryonic Antigen (CEA) using Micromechanical Biosensors

We have used arrays of micromechanical biosensors to detect carcinoembryonic antigen (CEA), a protein biomarker associated with various cancers such as colorectal, lung, breast, pancreatic, and bladder cancer. The sensing principle is based on the surface stress changes induced by antigen–antibody interaction on the micromechanical membrane (MM) surfaces. MM consists of a membrane suspended by four piezoresistive sensing components. The isotropic surface stress on the membrane results in a uniaxial stress in each sensing component, which efficiently improves the sensitivity. According to the experiments, it was revealed that MMs have surface stress sensitivities in the order of 2 (mJ/m). This matter allows them to detect CEA concentrations as low as 500 pg mL-1 or 3 pM. This indicates the fact that the self-sensing MM approach is beneficial for pathological tests.