Defect-mediated　engineering　has　been　proven　as　a　novel　and　effective　strategy　to　integrate　two　individual　materials　into　a　nanocomposite　to　boost　the　performance.　In　the　present　work,　nanocomposite　of　partially-unzipped　stacked-cup　carbon　nanofibers　(PUSCNFs)　decorated　with　platinum　nanoparticles　(Pt　NPs)　have　been　successfully　synthesized　through　the　defect-mediated　formation　method.　Owing　to　the　introduction　of　abundant　structural　defects　during　the　chemical　oxidation　process,　Pt　NPs　with　an　average　diameter　of　2-3　nm　were　uniformly　anchored　on　the　PUSCNFs　without　any　surfactant　involved.　As　comparison,　the　Pt　NPs　grown　on　the　stacked-cup　carbon　nanofibers　(SCNFs)　possessed　markedly　larger　nanoparticle　size　and　trended　to　aggregate.　The　electrochemical　properties　of　the　nanocomposite-modified　electrodes　for　biosensing　were　examined.　Our　results　showed　the　Pt-PUSCNFs　nanocomposite　possessed　optimal　electrocatalytic　activities　and　biosensing　performance　for　detection　of　biomolecules,　which　could　be　attributed　to　a　synergistic　effect　between　the　PUSCNFs　and　Pt　NPs　on　electron　transport　and　catalytic　properties.　We　anticipate　that　the　PUSCNFs　may　be　a　potential　support　material　for　construction　of　nanocomposites　with　good　performance.　(C)　2017　Elsevier　B.V.　All　rights　reserved.