Electrolyte-Free Nano-Electronic Sensor for the Rapid Quantification of DNA

Electric detection using a nanocomponent could lead to platforms for rapid and simple biosensing. Sensors composed of nanostructures have been described for applications requiring high sensitivity on account of their confined geometries. However, both fabrication and use of nanostructured sensors remain challenging. Here, we present a nano-electronic sensor, used as an amperometric biosensor, for the highly sensitive quantification of DNA. The proposed nano-electronic sensor is fabricated by a two-step process; 1) fabricate microscale-cantilever structure using ultraviolet (UV) lithography and anisotropic etching for reliable electrical measurement, and 2) immobilize single-walled carbon nanotubes (SWNCTs) onto the structure for generation of a high electric field. The electrical characteristics of nano-electronic sensor upon binding DNA are studied by I-V measurement in deionized (DI) water. When the DNA is dielectrophoretically captured onto the sensor, the electric current through DI water decreases. The sensitivity test shows that the signal is discernable from the noise level down to 100 attomolar (aM). Measurement results are consistent with fluorescence microscopy. Unlike other optical-based quantification methods, a nano-electronic sensor is capable of rapidly concentrating and detecting small amounts of DNA.