Hydrophilic Copolymer Bearing Dicyanomethylene-4H-pyran Moiety As Fluorescent Film Sensor for Cu2+ and Pyrophosphate Anion

The design of fluorescent sensors for pyrophosphate anion (P2O74−, PPi) has become a focus of considerable research in biological markers with realizing distinct advantages such as high sensitivity, easy detection, and wide dynamic ranges. A new strategy of incorporating the ion-sensitive fluorescent unit to form hydrophilic copolymer poly(HEMA-co-DCPDP) has been developed as a film sensor for Cu2+ and PPi. In general, the responsive characteristics of polymer-based fluorescent film for bioprocess are dependent on several factors, such as the permeability of ions into polymer matrix, the aggregation of polymer chains, and the strength of binding interaction between ions and polymeric sensors. To overcome these limitations, 2-hydroxyethyl methacrylate (HEMA) as a neutral hydrophilic chain segment is chosen as the monomer for its high hydrophilicity to improve ion permeability into the polymer matrix. Using the ensemble method, the related metal complex, poly(HEMA-co-DCPDP)-Cu2+, shows turn-on fluorescence and high sensitivity for PPi in both solution and thin film over other anions such as adenosine triphosphate (ATP) and phosphate (Pi). The low-cost hydyophilic copolymer film of poly(HEMA-co-DCPDP)-Cu2+ exhibits high sensitivity and rapid response to PPi with turn-on orange-red fluorescence, showing an ideal hydrophilic film strategy for low-cost anion chemosensors or chips to the online monitor and high-throughput bioprocessing in continuous system.