A Coumarin-Based Fluorescent Probe for Ratiometric Detection of Cu(2+) and Its Application in Bioimaging

The fluorescent probe L, based on naphthalimide-modified coumarin, was designed, synthesized, and characterized, which could recognize Cu(2+) from other cations selectively and sensitively in HEPES buffer (10 mM, Ph = 7. 4)/CH(3)CN (1:4, V/V). When the probe L interacted with Cu(2+), the color and the fluorescent intensity changed obviously and it provided the naked-eye detection for Cu(2+). The recognition mode between them was achieved by Job's plot, IR, MS, SEM, and (1)HNMR. In addition, test strips made from L could still interact with Cu(2+) in tap water effectively. The limit of detection (LOD) of L was 3.5 × 10(−6) M. Additionally, the density functional theory (DFT) calculation method was used to analyze the action mechanism of L toward Cu(2+). Importantly, the fluorescent probe L could demonstrate favorable selectivity toward Cu(2+) in Caenorhabditis elegans. Thus, L was considered to have some potential for application in bioimaging.