Lead　ion　(Pb2+,　a　heavy　metal　ion　existed　every　aspect　of　life)　is　one　of　the　most　important　hazards　for　environment　and　human　health.　Herein　we　design　an　in-situ　amplified　electronic　monitoring　system　for　sensitive　determination　of　Pb2+　on　Pb2+-specific　DNAzyme-modified　sensing　interface.　The　assay　consists　of　target-triggered　cleavage　of　Pb2+-specific　DNAzyme,　initiator　strand-induced　DNA　hybridization　chain　reaction,　formation　of　hemin/G-quadruplex　-based　DNAzyme　and　its　automatically　catalyzed　polymerization　of　aniline　monomer　along　the　double-stranded　DNA.　Experimental　results　indicated　that　the　catalytic　currents　of　the　as-produced　polyaniline　were　linearly　dependent　on　target　Pb2+　concentrations　from　0.05　to　50　nM　with　a　detection　limit　(LOD)　of　32　pM.　Such　a　synergistic　effect　of　hybridization　chain　reaction　with　DNAzyme-catalyzed　polymerization　provided　a　universal　platform　for　sensitive　screening　of　target　Pb2+,　thereby　holding　great　promise　for　application　in　practice.　(C)　2015　Elsevier　B.V.　All　rights　reserved.