This　work　designs　a　new　photoelectrochemical　(PEC)　sensing　system　for　the　detection　of　carcinoembryonic　antigens　(CEAs)　using　bismuth　ferrite　(BiFeO3)　nanostructures　as　photoactive　materials,　accompanied　by　the　target-controlled　release　of　glucose　from　multifunctional　mesoporous　silica　nanoparticles　(MSNs)　for　signal　amplification.　Glucose　molecules　were　gated　in　the　pores　via　the　hybridization　of　a　CEA　aptamer　with　anchor　DNA　(aDNA,　modified　on　the　mesoporous　silica　nanoparticles).　Upon　the　addition　of　the　target　CEA,　the　analyte　competitively　reacted　with　the　aptamer　to　open　the　gate,　thus　resulting　in　the　release　of　glucose　molecules　from　the　MSNs.　Based　on　the　oxidization　of　glucose　in　the　presence　of　glucose　oxidase,　the　as-generated　enzymatic　product　(H2O2)　served　as　an　electron　acceptor　to　enhance　the　photocurrent　generated　by　the　BiFeO3　nanostructures　under　visible　light　irradiation.　In　this　way,　an　in　situ　amplified　photocurrent　could　be　achieved　in　that　the　low-concentration　target　CEA　could　cause　the　release　of　numerous　glucose　molecules.　Experimental　results　suggested　that　the　photocurrent　obtained　from　the　BiFeO3-based　photoactive　materials　increased　with　increasing　CEA　concentration　and　showed　a　good　linear　dependence　on　the　logarithm　of　the　CEA　level　from　5.0　pg　mL-1　to　50　ng　mL-1　under　optimal　conditions.　Additionally,　the　BiFeO3-based　PEC　sensing　platform　also　showed　good　stability　and　favorable　selectivity,　and　satisfactory　accuracy　for　CEA　detection　in　human　serum　specimens　in　comparison　with　a　reference　CEA　ELISA　kit.　The　good　analytical　performance　of　the　BiFeO3-based　PEC　sensing　method　makes　it　a　promising　tool　for　the　efficient,　low-cost　and　convenient　detection　of　CEAs　in　disease　diagnosis.　©　2017　The　Royal　Society　of　Chemistry.