An　amperometric　biosensor　for　the　detection　of　organophosphate　and　carbamate　pesticides　was　developed　based　on　the　immobilization　of　acetylcholinesterase　(AChE)　on　regenerated　silk　fibroin　(SF)　matrix　by　non-covalent　adsorption.　SF　and　AChE　were　coated　sequentially　on　the　surface　of　the　glassy　carbon　electrode　(GCE)　which　was　modified　with　multiwall　carbon　nanotube　(MWNTs).　The　obtained　biosensor　was　denoted　as　AChE-SF/MWNTs/GCE.　The　atomic　force　microscopy　images　showed　that　the　SF　matrix　provided　a　more　homogeneous　interface　for　the　AChE　immobilization.　The　aggregation　of　immobilizing　AChE　was　therefore　avoided.　The　cyclic　voltammogram　of　thiocholine　at　this　biosensor　exhibited　a　well　defined　oxidation　peak　at　0.667　V　(vs.　SCE).　The　inhibition　rate　of　methyl　parathion　to　the　immobilized　AChE　was　proportional　to　the　logarithm　of　the　concentration　of　methyl　parathion　over　the　range　of　the　concentration　of　methyl　parathion　from　3.5　x　10(-6)　to　2.0　x　10(-3)M　with　a　detection　limit　of　5.0　x　10(-7)　M.　Similarly,　the　linearly　response　range　of　carbaryl　was　from　1.0　x　10(-7)　to　3.0　x　10(-5)M　with　a　detection　limit　of　6.0　x　10(-8)　M.　The　experimental　results　indicate　that　AChE　not　only　can　be　immobilized　steadily　on　the　SF　matrix,　but　also　the　bioactivity　of　immobilizing　AChE　can　be　preserved　effectively.　(C)　2012　Elsevier　B.V.　All　rights　reserved.