A cucurbit[6]uril-carbon dot system: a potentially new bioimaging agent

Abstract

We report novel cucurbit[6]uril (Q[6])/carbon quantum dots (CQDs) prepared by solvothermal and nitrogen doped methods. The m-Q[6]-CQDs have been characterized by FTIR, XRD and X-ray photoelectron spectroscopy. The obtained m-Q[6]-CQDs exhibit good water dispersibility, photostability and strong blue fluorescence emission. The m-Q[6]-CQDs also showed good selectivity for metal ions. When Hg²⁺ is present, the fluorescence is quenched, but upon the addition of Al³⁺, the fluorescence is enhanced. It was also shown that the fluorescence of the m-Q[6]-CQDs can resist both the interference from other metal ions as well as high ionic strength environments. The m-Q[6]-CQDs were utilized for the optical bioimaging of human prostate cancer (PC-3) cells, and were found to exhibit both low cytotoxicity and excellent biocompatibility.