A Fluorescent Furan‐based Probe with Protected Functional Groups for Highly Selective and Non‐Toxic Imaging of HT‐29 Cancer Cells and 4T1 Tumors

Abstract

Most of the previously reported fluorescent organic probes for tumor imaging have significant limitations including chemical toxicity, low Stokes shift value, and the inability for selective accumulations in tumors. To overcome these challenges, we synthesized two fluorescent probes with protected polar functional groups to enhance the non‐toxicity nature and increase the selectivity toward tumors. In addition, the structural rigidity of the fluorescent probes was increased by embedding aromatic rings in the probe structure. This issue enables us to obtain ultrabright cell images due to enhanced fluorescence quantum yield (ФFL) values. After spectral characterizations, the applicability of two furan‐based and imidazole‐based fluorescent probes (abbreviated as DCPEF and DBPPI, respectively) was investigated for in vitro and in vivo imaging of cancer cells. The MTT cytotoxicity assay showed that probe DCPEF has minimal effects against HT‐29 (cancer) and Vero (normal) cells. The probe DCPEF produced ultrabright fluorescence images from HT‐29 cells. In addition, in vivo imaging of cancer cells showed that probe DCPEF selectively accumulates in the 4T1 tumor in mice. The chemical stability and high degree of selectivity for tumor cells make DCPEF an appropriate candidate to be used as a standard probe for cancer cell imaging.