A　novel　fluorescent　sensor　for　DNA　sequence　has　been　designed　by　taking　advantages　of　copper　nanoparticles　(CuNPs)　selectively　formed　on　double　stranded　(ds)　DNA　template　and　Cu(I)-catalyzed　azide-alkyne　cycloaddition　(CuAAC)　reaction.　Copper(II)　is　derived　from　CuNPs　which　previously　formed　on　the　dsDNA　template,　and　then　copper(II)　is　reduced　to　copper(I)　by　ascorbate,　which　in　turn　induced　CuAAC　reaction　between　the　weak-fluorescent　compound　(3-azido-7-hydroxycoumarin)　and　propargyl　alcohol　to　form　strong　fluorescence　compounds　(1,2,3-triazole　compounds).　Since　CuNPs　are　accumulated　efficiently　in　the　major　groove　of　dsDNA　and　ssDNA　has　no　groove,　it　indicates　that　the　proposed　sensor　owns　the　merits　of　low　detection　limit,　high　sensitivity　and　selectivity　for　mutational　p53　sequence　detection.　Additionally,　the　method　has　been　successfully　applied　to　recognize　the　sequence　which　contains　a　single-base　mismatch　in　the　short　human　p53　gene　fragment.　Furthermore,　it　has　also　been　applied　to　detect　DNA　sequence　in　complex　medium　(hela　cellular　homogenate)　with　satisfactory　results.　(C)　2012　Elsevier　B.V.　All　rights　reserved.