DNA Wrapped Metallic Single-walled Carbon Nanotube Sensor for Pb (II) Detection

Based on the interaction of Pb (II) ions with nucleic acid via phosphate groups and nucleic bases of the deoxyribonucleic acid structure, an electrochemical sensor with DNA wrapped metallic single-walled carbon nanotube (SWNT) has been fabricated for sensitive and selective detection of lead ion (Pb2+). The sensor shows a rapid differential pulse voltammetry signal response to the content of Pb2+, and a quantitative detection of Pb2+ has been established with an expanded linear responsive range from 1x10(-9) to 1.0x10(-8) mol L-1 (R = 0.9979) and a detection limit of 4.1x10(-10) mol L-1 in buffer solution (pH 5.0). Furthermore, the sensor displayed a negligible differential pulse voltammetry signal response for other metal ions, indicating its high selectivity for Pb2(+). The investigation of electrochemical impedance spectroscopy and cyclic voltammetry in buffer solution demonstrated that metallic SWNTs played an important role in enlarging current response and increasing sensitivity of the sensor.