A cucurbit[8]uril-based supramolecular polymer constructed via outer surface interactions: Use as a sensor, in cellular imaging and beyond

In recent years, most of the constructions on cucurbit[n]uril-based supramolecular polymers have been based on host–guest chemistry, however, this limits the choice of host and guest. Herein, we present a newly designed supramolecular polymer, namely Q[8]@PEG-HPTS formed by utilizing outer surface Q[8] interactions. In aqueous solution, the supramolecular polymer Q[8]@PEG-HPTS was obtained quickly and simply by mixing Q[8] with PEG-HPTS, where after, a variety of characterization techniques were employed to confirm the structure of the Q[8]@PEG-HPTS. The ability of this system to selectively recognize metal ions as well as pesticide molecules was also investigated; selectivity was observed for Fe3+ and paraquat. The biocompatibility and excellent fluorescence properties associated with the constituents of the supramolecular polymer allowed for the imaging of HeLa cells. This system could image and trace the nucleus through the cytoplasm, indicating that it could enter and internalize HeLa cells. Finally, by continuously adjusting the ratio between Q[8] and PEG-HPTS, a Q[8]@PEG-HPTS hydrogel was obtained. This hydrogel exhibited a stimulated temperature response, and opens up further possibilities for exploring the applications of such supramolecular polymers.