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pH-Triggered Disaggregation-Induced Emission (DIE) Probe for Sensoring Minor-pH Changes in Near Infrared Fluorescence region

Jing, Titao, Yan, Lifeng
Talanta 2017
dyes, fluorescence, nanoparticles, pH, schiff bases
A new strategy for pH-responsive near infrared (NIR) cyanine dye, based on the concept of triggered disaggregation-induced emission (DIE), has been developed. Schiff base group was introduced to the molecular scaffold of Cy7, and promoted the aggregation of cyanine in pH7.4 buffer due to the strong π-π interaction. While in an acidic (pH 5.8) environment, the Schiff base group was hydrolyzed by acid and the nanoparticles were disaggregated. The vanishing of the intermolecular aggregation-caused quenching thus induced a fluorescence recovery of 96 folds. Moreover, abundant kinds of Schiff base provide more potential cyanine dyes for pH-responsive ultrahigh NIR fluorescence “Off/On” ratio, which could work as the intelligent bio-imaging probes in near future.