Disposable DNA biosensor based on thin-film gold electrodes for selective Salmonella detection

The development of a disposable electrochemical biosensor for selective Salmonella detection in presence of other pathogens is described. The device is based on thin-film gold electrodes and is fabricated employing standard microsystems technology. The method involves the immobilization of a thiolated capture probe able to hybridize with its complementary sequence (target). The hybridization event is detected using the ruthenium complex, [Ru(NH3)5L]2+, where L is [3-(2-phenanthren-9-yl-vinyl)-pyridine] as electrochemical indicator. The combination of MEMS technology to fabricate electrodes with a predetermined configuration and the use of a hybridization redox indicator which interacts preferentially with dsDNA gear to the development of an approach that not only quantifies complementary target sequence, but also is selective to Salmonella in presence of other pathogens, which can act as potential interferents. In base of these results, a multianalyte detection platform including Salmonella, Lysteria and Escherichia coli has been developed.