Molecular Engineering of Hemicyanine Scaffold for Peroxynitrite‐Activated Chemiluminescence Imaging

ABSTRACT Chemiluminescence eliminates interference from real‐time excitation light, thereby maximizing the signal‐to‐noise ratio of imaging. However, the reported chemiluminescent scaffolds remain limited, and the development of novel and efficient chemiluminescent scaffolds is critical and urgent. Herein, we synthesized a series of peroxynitrite (ONOO − )‐activated chemiluminescent probes based on a hemicyanine scaffold through molecular engineering, and systematically investigated optical properties as well as their response mechanisms. Upon reaction with ONOO − , the vinylene units in the hemicyanine scaffold are oxidatively degraded, thereby emitting a chemiluminescent signal in the 400–650 nm wavelength range. Furthermore, under the defined conditions, it was found that the tissue penetration of ONOO − ‐activated chemiluminescence (up to 12 mm) is deeper than that of 660 nm‐activated afterglow luminescence and the fluorescence of hemicyanine scaffolds. In cell imaging, in addition to sensitive ONOO − response via chemiluminescence, it can also respond superiorly to ONOO − through well‐separated dual fluorescence channels. In conjunction with satisfactory biocompatibility, the probe showed favorable responsiveness and high sensitivity toward ONOO − levels in lipopolysaccharide‐induced inflammation induced. These findings provide solid and reliable experience for the discovery and construction of novel and versatile chemiluminescent scaffolds.