A water-soluble poly-indole-triphenyl-nido-carborane of zwitterionic probe strategy applied to tumor cell imaging

Boron neutron capture therapy (BNCT) is a promising tumor treatment approach that has gained significant attention in recent years. While o -carborane has demonstrated excellent tumor-targeting properties, its limited water solubility and inability to be visually monitored for entry into tumor cells hinder its effectiveness in tumor therapy. In this study, we synthesized three poly-indole-triphenyl quaternary ammonium salts and combined them with nido -carborane. The resulting water-soluble poly-indole-triphenyl- nido -carborane of zwitterionic probe was designed for the rapid, real-time, and accurate detection of boron-containing drugs. The UV and fluorescence ranges were then observed in different solvents, and it was found that the maximum absorption wavelength of the three polymers was concentrated in the range of 547–557 nm and the emission wavelength in the range of 564–571 nm. The three polymers exhibit distinct morphologies, including tadpole, spherical, and clustered, as confirmed by electron microscopic imaging. DLS measured their average particle size between 200 and 350 nm. Moreover, the three polymers were used for tumor cell imaging, and all of them could pass through the cell membrane and enter A549, HCT116, and Hela cells. In summary, the poly-indole-triphenyl- nido -carborane quaternary salts synthesized in this paper have good biocompatibility and targeting properties, which provide important reference significance for the design and research of future BNCT reagents. Graphical Abstract