In　this　paper,　we　have　reported　on　novel　phosphatidylserine-functionalized　AuNPs　(gold　nanoparticles)　for　the　visual　detection　of　Cu2+　by　employing　phosphatidylserine　for　Cu2+　recognition　and　AuNPs　for　signal　generation.　The　phosphatidylserine　(1,2-dioleoyl-sn-glycero-3-phospho-l-serine,　DOPS)　was　covalently　assembled　on　the　AuNP　surface　to　obtain　DOPS-functionalized　AuNPs.　It　was　demonstrated　that　DOPS-functionalized　AuNPs　could　specifically　bind　Cu2+　and　lead　to　the　aggregation　of　AuNPs,　which　gave　rise　to　a　colour　change　from　wine-red　to　blue　and　a　new　absorption　band　around　650　nm.　This　provides　a　sensing　platform　for　the　simple,　rapid　and　field　portable　colorimetric　detection　of　Cu2+.　By　using　the　sensing　platform,　a　selective　and　sensitive　visual　biosensor　for　the　detection　of　Cu2+　was　developed.　The　proposed　biosensor　has　outstanding　analytical　advantages　such　as　good　stability,　relatively　high　sensitivity,　low　cost　and　short　analysis　time.　It　can　be　used　to　detect　concentrations　of　Cu2+　as　low　as　30　μM　in　river　water　by　observation　with　the　naked　eye　and　of　1.55　μM　Cu2+　in　river　water　by　UV-visible　spectrophotometry,　within　10　min　and　with　a　recovery　of　98-103%　and　a　relative　standard　deviation　(RSD)　<　4%　(n　=　6).　The　proposed　biosensor　is　promising　for　on-site　detection　of　trace　Cu2+　in　clinical　diagnosis　or　environmental　monitoring.　©　2014　the　Partner　Organisations.