Electrochemical Gold(III) Sensor with High Sensitivity\nand Tunable Dynamic Range

Abstract

We\nreport the design and fabrication of a sensitive, specific,\nand selective electrochemical ion (E-ION) sensor for detection of\nAu­(III). The signaling mechanism is based on the interactions between\nAu­(III) and adenine; formation of these complexes rigidifies the methylene\nblue (MB)-modified oligoadenine probes, resulting in a concentration-dependent\nreduction in the MB signal. The dynamic range of the sensor can be\ntuned by simply changing the length of the DNA probe (six (A6) or\n12 (A12) adenines). Independent of the probe length, both sensors\nhave demonstrated to be sensitive, with a limits of detection of 50\nand 20 nM for the A6 and A12 sensors, respectively. With further optimization,\nthis sensing strategy may offer a promising approach for analyzing\nAu­(III).