This　study　demonstrates　a　facile　and　feasible　strategy　toward　the　development　of　advanced　electrochemical　immunosensors　based　on　chemically　functionalized　magnetic　mesoporous　organic-inorganic　hybrid　nanomaterials,　and　the　preparation,　characterization,　and　measurement　of　relevant　properties　of　the　immunosensor　for　detection　of　carcinoembryonic　antigen　(CEA,　as　a　model　analyte)　in　clinical　immunoassays.　The　as-prepared　nanomaterials　composed　of　a　magnetic　mesoporous　NiCo2O4　nanosheet,　an　interlayer　of　Nafion/thionine　organic　molecules　and　a　nanogold　layer　show　good　adsorption　properties　for　the　attachment　of　horseradish　peroxidase-labeled　secondary　anti-CEA　antibody　(HRP-anti-CEA).　With　a　sandwich-type　immunoassay　format,　the　functional　bionanomaterials　present　good　analytical　properties　to　facilitate　and　modulate　the　way　it　was　integrated　onto　the　electrochemical　immunosensors,　and　allows　the　detection　of　CEA　at　a　concentration　as　low　as　0.5　pg/mL.　Significantly,　the　immunosensor　could　be　easily　regenerated　by　only　using　an　external　magnet　without　the　need　of　any　dissociated　reagents.　Importantly,　the　as-synthesized　magnetic　mesoporous　NiCo2O4　nanomaterials　could　be　further　extended　for　detection　of　other　biomarkers　or　biocompounds.　©　2011　American　Chemical　Society.