Label-Free Attomolar Detection of Proteins Using Integrated Nanoelectronic and Electrokinetic Devices

High‐sensitivity screening of biomarkers is critical to areas ranging from early disease detection and diagnosis to bioterrorism surveillance. Here the development of integrated nanoelectronic and electrokinetic devices for label‐free attomolar detection of proteins is reported. Electrically addressable silicon nanowire field‐effect transistors and electrodes for electrokinetic transport are integrated onto a common sensor chip platform, and the nanowire devices are subsequently functionalized with receptors for selective biomarker detection. Nanowire devices modified with monoclonal antibody for prostate specific antigen exhibit close to a 104 increase in sensitivity due to streaming dielectrophoresis and corresponding electrostatic contribution to the binding affinity after application of an AC electric field. The devices are also modified with receptors for cholera toxin subunit B and achieve a similar enhancement. These results show general applicability of this method, and could open up opportunities in early stage disease detection and the analysis of proteins from single cells. Streaming dielectrophoresis and the corresponding electrostatic contribution to binding affinity after application of an AC electric field pushes the detection limit of an integrated nanoelectronic and electrokinetic device down to the attomolar level. The mechanism works for devices modified with an antibody for antigen detection and with cellular receptors for toxin screening.