In　this　study,　a　highly　sensitive　and　selective　fluorescent　Zn2 +　probe　which　exhibited　excellent　biocompatibility,　water　solubility,　and　cell-membrane　permeability,　was　facilely　synthesized　in　a　single　step　by　grafting　polyethyleneimine　(PEI)　with　quinoline　derivatives.　The　primary　amino　groups　in　the　branched　PEI　can　increase　water　solubility　and　cell　permeability　of　the　probe　PEIQ,　while　quinoline　derivatives　can　specifically　recognize　Zn2 +　and　reduce　the　potential　cytotoxicity　of　PEI.　Basing　on　fluorescence　off-on　mechanism,　PEIQ　demonstrated　excellent　sensing　capability　towards　Zn2 +　in　absolute　aqueous　solution,　where　a　high　sensitivity　with　a　detection　limit　as　low　as　38.1 nM,　and　a　high　selectivity　over　competing　metal　ions　and　potential　interfering　amino　acids,　were　achieved.　Inspired　by　these　results,　elementary　logic　operations　(YES,　NOT　and　INHIBIT)　have　been　constructed　by　employing　PEIQ　as　the　gate　while　Zn2 +　and　EDTA　as　chemical　inputs.　Together　with　the　low　cytotoxicity　and　good　cell-permeability,　the　practical　application　of　PEIQ　in　living　cell　imaging　was　satisfactorily　demonstrated,　emphasizing　its　wide　application　in　fundamental　biology　research.　©　2016