The　authors　describe　a　photoelectrochemical　(PEC)　immunoassay　for　determination　of　aflatoxin　B-1　(AFB(1))　in　foodstuff.　The　competitive　immunoreaction　is　carried　out　on　a　microplate　coated　with　a　capture　antibody　against　AFB(1)　using　AFB(1)-bovine　serum　albumin　(BSA)-liposome-coated　mesoporous　silica　nanoparticles　(MSN)　loaded　with　L-cysteine　as　a　support.　The　photocurrent　is　produced　by　a　photoactive　material　consisting　of　cerium-doped　Bi2MoO6.　Initially,　L-cysteine　acting　as　the　electron　donor　is　gated　in　the　pores　by　interaction　between　mesoporous　silica　and　liposome.　Thereafter,　AFB(1)-BSA　conjugates　are　covalently　bound　to　the　liposomes.　Upon　introduction　of　the　analyte　(AFB(1)),　the　labeled　AFB(1)-BSA　complex　competes　with　the　analyte　for　the　antibody　deposited　on　the　microplate.　Accompanying　with　the　immunocomplex,　the　liposomes　on　the　MSNs　are　lysed　upon　addition　of　Triton　X-100.　This　results　in　the　opening　of　the　pores　and　in　a　release　of　L-cysteine.　Free　cysteine　then　induces　the　electron-hole　scavenger　of　the　photoactive　nanosheets　to　increase　the　photocurrent.　The　photocurrent　(relative　to　background　signal)　increases　with　increasing　AFB(1)　concentration.　Under　optimum　conditions,　the　photoactive　nanosheets　display　good　photoelectrochemical　responses,　and　allow　the　detection　of　AFB(1)　at　a　concentration　as　low　as　0.1　pg.mL(-1)　within　a　linear　response　in　the　0.3　pg.mL(-1)　to　10　ng.mL(-1)　concentration　range.　Accuracy　was　evaluated　by　analyzing　naturally　contaminated　and　spiked　peanut　samples　by　using　a　commercial　AFB(1)　ELISA　kit　as　the　reference,　and　well-matching　results　were　obtained.