A highly sensitive and specific electrochemical sensing method for robust detection of Escherichia coli lac Z gene sequence

Based on the interaction mode of capture probe-target-signal probe (CP-T-SP), a simple but efficient electrochemical sensing method is developed for robust detection of Escherichia coli (E. coli) lac Z gene sequence. The sensing system is simply composed of two probes with CP attached to the surface of gold electrode and methylene blue (MB)-labeled SP free in the detecting solution. Two duplexes are formed with the target DNA, an E. coli lac Z gene sequence, hybridizing with two ends of CP and SP separately. This structure can position the MB labels near to the electrode surface, thereby resulting in the change of detecting current. The proposed sensor exhibits a high sensitivity with a detection limit of similar to 30 fM for target DNA and good mismatch discrimination ability (MDA). This method can also be applied to the construction of other sensors for the analysis of similar designated pathogenic bacteria gene sequence (PBGS). 2014 Elsevier B.V. All rights reserved.