Highly efficient Far Red/Near-Infrared fluorophores with aggregation-induced emission for bioimaging

•A series of highly efficient Far Red/Near-Infrared fluorescent compounds with aggregation-induced emission properties.•These compounds exhibit facile fabrication into uniform compound-loaded Pluronic F127 NPs.•These compounds are effective fluorescent probes for cancer cells with excellent properties.

Organic fluorescent probes play an important role in modern biomedical research, such as biological sensing and imaging. However, the development of organic fluorophores with efficient aggregate state emissions expanded to the red to near-infrared region is still challenging. Here, we present a series of highly efficient Far Red/Near-Infrared (FR/NIR) fluorescent compounds with aggregation-induced emission (AIE) properties by attaching electron donor and accepter to tetraphenylethene (TPE) moieties through a simple synthesis method. These compounds exhibited the pronounced fluorescence enhancement in aggregate state, the red to near infrared emission, and can be facilely fabricated into uniform compounds-loaded Pluronic F127 NPs. The emission maximum of the NPs fabricated by the self-assembly method is in the range of 550-850 nm and the highest fluorescent quantum yield can get to 15.2%. The biological imaging of NPs of compound 1 and 2 for A549 lung cancer cell indicates that these compounds are effective fluorescent probes for cancer cells with high specificity, high photostability and good fluorescence contrast.

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