Synergy of CO2 Response and Aggregation-Induced Emission in a Block Copolymer: A Facile Way To See Cancer Cells

Carbon dioxide (CO2), an important gas molecule metabolite produced by the tricarboxylic acid cycle, is a direct signal for identifying cancers in cells and tissues. Herein, design and synthesis of a novel breathable block polymer supramolecular assembly probe consisting of a hydrophilic block, an amidine-containing CO2-responsive block, and an aggregation-induced emission (AIE) luminescence block to detect CO2 metabolized by cancer cells is reported. The triblock copolymer poly-(4-undecoxy tetraphenyl ethylene methacrylate)-b-poly-((N-amidino)-(2,3-dihydro-1H-1, 4-methyl-1, 2,3-triazole)-(ethenylbenzene))-b-poly(ethylene oxide) (PTPE-b-PAD-b-PEO) was successfully synthesized and characterized. This triblock copolymer could be self-assembled into breathable aqueous solution vesicles. In the presence of CO2, the amidine-containing CO2-responsive block (PAD block) of the vesicle inhales an amount of CO2, which causes the volume of the vesicle to expand. The expansion of the vesicle induces the aggregation of the AIE luminescence block (PTPE block), which resulted in the fluorescence intensity enhancement. The supramolecular vesicles exhale CO2, and the volume and AIE phenomenon of the vesicles decrease when N-2 is passed into the solution. On the basis of this reversible change of fluorescence intensity, HeLa cervical cancer cells, CNE1 nasopharynx cancer cells, 5-8F nasopharynx cancer cells, 16HBE human bronchial epithelial cells, and GES-1 human gastric mucosa epithelial cells have all been successfully detected and identified.