A　sensitive　electrochemical　immunosensor　for　the　fast　screening　of　brevetoxin　B　(BTX-2)　in　food　samples　was　developed　by　means　of　immobilizing　BTX-2-bovine　serum　albumin　conjugate　(BTX-2-BSA)　on　the　gold　nanoparticles-decorated　amine-terminated　poly(amidoamine)　dendrimers　(AuNP-PAADs).　The　presence　of　gold　nanoparticles　greatly　improved　the　conductivity　of　the　PAADs,　and　three-dimensional　PAADs　increased　the　surface　coverage　of　the　biomolecules　on　the　electrode.　Under　optimal　conditions,　three　types　of　immunosensor,　i.e.　with　AuNPs,　PAADs,　or　AuNP-PAADs,　were　used　for　the　determination　of　BTX-2　in　a　competitive-type　immunoassay　format　using　horseradish　peroxidase-labeled　anti-BTX　antibodies　(HRP-anri-BTX-2)　as　trace　in　the　H(2)O(2)-o-phenylenediamine　(o-PD)　system.　A　low　detection　limit　(LOD)　of　0.01　ng/mL　and　a　wide　dynamic　working　linear　range　of　0.03-8　ng/mL　BTX-2　using　AuNP-PAADs　as　matrices　were　obtained　in　comparison　with　those　of　only　using　AuNP　or　PAADs.　Intra-batch　assay　precision　was　substantially　improved　by　resorting　to　the　AuNP-PAADs　manifold.　The　proposed　method　features　unbiased　identification　of　negative　(blank)　and　positive　samples.　No　significant　differences　were　encountered　in　the　analysis　of　the　spiking　real　samples　between　the　electrochemical　immunosensor　and　liquid　chromatography　for　the　determination　of　BTX-2.　Importantly,　this　method　provided　a　biocompatible　immobilization　and　a　promising　immunosensing　platform　for　analytes　with　small　molecules　in　the　analysis　and　detection　of　food　safety.　(C)　2010　Elsevier　B.V.　All　rights　reserved.