A　new　electrochemical　immunosensor　for　sensitive　determination　of　thyroid-stimulating　hormone　(TSH)　was　designed　by　using　redox-active　nanogold-functionalized　magnetic　beads　(GoldMag)　as　signal　tags　on　the　nanogold-graphene　interface.　To　construct　such　GoldMag　nanostructures,　polyethyleneimine-functionalized　magnetic　beads　(PEI-MBs)　were　initially　prepared　by　using　a　wet　chemical　method,　and　the　electroactive　thionine　molecules　and　gold　nanoparticles　were　then　alternately　immobilized　on　the　surface　of　PEI-MBs　by　using　an　opposite-charged　adsorption　technique　and　an　in　situ　synthesis　method,　respectively.　The　synthesized　GoldMag　nanostructures　were　utilized　as　signal　tags　for　the　label　of　horseradish　peroxidase-anti-TSH　conjugates　(HRP-anti-TSH).　With　a　sandwich-type　immunoassay　format,　the　conjugated　signal　tags　on　the　transducer　were　increased　with　the　increasing　TSH　concentration　in　the　sample,　thus　enhancing　the　signal　of　the　electrochemical　immunosensor　due　to　the　labeled　HRP　toward　the　catalytic　reduction　of　H2O2.　Under　optimal　conditions,　the　current　was　proportional　to　the　logarithm　of　TSH　concentration　ranging　from　0.01　to　20　mu　IU　mL(-1)　in　pH　6.0　HAc-NaAc　containing　6　mM　H2O2.　The　detection　limit　(LOD)　was　0.005　mu　IU　mL(-1)　TSH　at　3s(B).　The　immunosensor　displayed　an　acceptable　reproducibility,　stability　and　selectivity.　In　addition,　the　methodology　was　evaluated　with　human　serum　specimens,　receiving　good　correlation　with　results　from　commercially　available　electrochemiluminescent　analyzer.　(C)　2011　Elsevier　B.V.　All　rights　reserved.