Near-infrared fluorescence probes based on disassembly-induced emission pyrene derivatives

Organic near-infrared dyes are commonly used for bioimaging due to their low photodamage and high penetration depth into biological tissue. Pyrene is an aromatic compound with a large pi-conjugation and has the potential for near-infrared emission. However, the wide band gap of pyrene limits its use in biological applications. In this study, we designed and synthesized a new near-infrared fluorophore, a pyrene derivative (PYN), by incorporating N,N-dimethyl and pyridine groups into the pyrene core. PYN exhibited fluorescence emission at approximately 730 nm, but with weak emission in aqueous solutions. The fluorescence emission was significantly (50 times) enhanced by co-assembly with cucurbit [8]uril (denoted as CB[8]). In addition, the co-assemblies possessed exceptional biocompatibility and photostability, which made them suitable for labeling HeLa cells for fluorescence imaging. The fluorescence emission included near infrared and was significantly enhanced (50 times) by co-assembly with cucurbit[8]uril.