A　simple　turn-on　and　homogeneous　aptasensor,　which　relies　on　target　induced　formation　of　silver　nanoclusters　(Ag　NCs),　was　developed　for　the　determination　of　platelet-derived　growth　factor　B-chain　homodimer　(PDGF-BB).　The　aptasensor　contains　two　hairpin　DNA　probes　termed　as　P1　and　P2.　P1　consists　of　the　aptamer　sequence　of　PDGF-BB.　Meanwhile,　P2　contains　the　Ag　NCs　nucleation　sequence,　which　is　blocked　by　the　hairpin　stem　region.　P1　and　P2　can　co-exist　metastably　in　the　absence　of　PDGF-BB　and　maintain　hairpin　structure.　However,　in　the　presence　of　PDGF-BB,　the　binding　of　PDGF-BB　with　aptamer　will　result　in　the　hybridization　between　P1　and　P2,　and　release　the　Ag　NCs　nucleation　sequence.　In　this　case,　Ag　NCs　can　be　formed　via　the　reduction　of　Ag+　by　NaBH4.　By　monitoring　the　increase　in　fluorescence　intensity,　we　could　detect　the　target　protein　with　high　sensitivity.　The　detection　limit　of　this　aptasensor　is　0.37　nM,　which　is　comparable　with　that　of　other　reported　aptasensors.　Furthermore,　this　proposed　aptasensor　shows　high　selectivity　toward　its　target　protein.　Thus,　the　proposed　aptasensor　based　on　target　induced　formation　of　Ag　NCs　could　be　used　as　a　sensitive　and　selective　platform　for　the　detection　of　target　protein.　(C)　2012　Elsevier　B.V.　All　rights　reserved.