Paper　based　microfluidics　(mu　PADs)　with　advantages　of　portability,　low　cost,　and　ease　of　use　have　attracted　extensive　attention.　Here　we　describe　a　novel　method　that　integrates　glucoamylase-trapped　aptamer-crosslinked　hydrogel　for　molecular　recognition　with　cascaded　enzymatic　reactions　for　signal　amplification　and　a　mu　PAD　for　portable　readout.　Upon　target　introduction,　the　hydrogel　decomposes　to　release　glucoamylase,　which　catalyzes　the　hydrolysis　of　amylose　to　produce　a　large　amount　of　glucose.　With　a　simple　folding　of　the　mu　PAD,　the　sample　solution　containing　glucose　product　wicks　and　diffuses　in　parallel　to　each　test-zone　to　carry　out　homogeneous　assays,　where　glucose　is　used　to　produce　12　for　brown　color　visualization　through　multiple　enzymatic　and　chemical　cascade　reactions.　Through　color　gradient　changes　based　on　different　concentrations　of　the　target,　a　semiquantitative　assay　is　achieved　by　the　naked　eye,　and　quantitation　can　be　obtained　by　handheld　devices.　Detection　of　cocaine　in　buffer　and　urine　was　performed　to　demonstrate　the　utility　of　the　hydrogel-mu　PAD　system.　More　importantly,　the　hydrogel-mu　PAD　system　can　be　extended　to　the　detection　of　various　targets　by　incorporating　the　corresponding　aptamer　into　the　hydrogel.　The　hydrogel-mu　PAD　system　reported　here　provides　a　new　platform　for　portable,　disposable　and　visual　detection　of　a　wide　range　of　targets.　(C)　2015　Elsevier　B.V.　All　rights　reserved.