In　this　paper,　we　reported　a　novel　electrochemical　aptasensor　based　on　an　inverted　aptamer　beacon　(IAB).　The　IAB　architecture　with　a　hairpin　structure　consisted　of　an　aptamer　arm　and　a　ferrocene　(Fc)-labeling　signal　arm,　and　was　inverted　on　the　electrode　through　a　thiol-linker　on　the　middle　site　of　its　loop.　The　inverted　immobilization　strategy　prevented　the　end-labeling　of　ferrocene　tag　from　approaching　the　electrode,　thus　resulting　in　a　weak　electrochemical　signal.　In　the　presence　of　thrombin,　binding　of　target　with　the　aptamer　arm　displaced　the　signaling　arm,　producing　a　flexible　single-stranded　element,　i.e.　internal-displacement　which　allowed　Fc　tag　to　collide　with　the　electrode,　thereby　producing　a　relatively　strong　electrochemical　signal.　By　monitoring　the　increased　signal,　thrombin　could　be　readily　detected　in　the　signal-on　mode　with　a　detection　limit　(LOD)　of　0.21　nM.　Inspiringly,　the　IAB-based　strategy　required　no　auxiliary　strands　and　did　not　depend　on　structure-switching　of　specific　aptamer/target　couple,　thus　presenting　as　a　generalized　method　for　fabrication　of　other　electrochemical　aptasensors.　(C)　2014　Elsevier　B.V.　All　rights　reserved.