A dual-probe surface-co-immobilization-based electrochemical sensor for highly sensitive and tunable specific detection of a designated DNA

摘要: Abstract A “signal on” electrochemical sensing method was established for the detection of a designated 24-base DNA. This sensor system shows simple structure with only composing three probes. One capturing probe ( CP ) and one assistant AP are co-immobilized onto Au electrode surface in short / duplex state, methylene blue (MB) modified signaling SP is free solution. Before adding target, low background signal helpful improving sensitivity obtained efficient electron transfer because MB labels far from surface; after longer more stable /target formed between target undoes former to release , which induces formation another duplex. can drive close much higher transfer, thereby producing large signal. The proposed features high limit (DL) ∼10 fM target. When used discriminating mismatched also exhibits good ability its adjustability.