An integrated logic system for time-resolved fluorescent “turn-on” detection of cysteine and histidine base on terbium (III) coordination polymer–copper (II) ensemble

Cysteine (Cys) and histidine (His) both play indispensable roles in many important biological activities. An enhanced Cys level can result in Alzheimer's and cardiovascular diseases. Likewise, His plays a significant role in the growth and repair of tissues as well as in controlling the transmission of metal elements in biological bases. Therefore, it is meaningful to detect Cys and His simultaneously. In this work, a novel terbium (III) coordination polymer–Cu (II) ensemble (Tb³⁺/GMP-Cu²⁺) was proposed. Guanosine monophosphate (GMP) can self-assemble with Tb³⁺ to form a supramolecular Tb³⁺ coordination polymer (Tb³⁺/GMP), which can be suited as a time-resolved probe. The fluorescence of Tb³⁺/GMP would be quenched upon the addition of Cu²⁺, and then the fluorescence of the as-prepared Tb³⁺/GMP-Cu²⁺ ensemble would be restored again in the presence of Cys or His. By incorporating N-Ethylmaleimide and Ni²⁺ as masking agents, Tb³⁺/GMP-Cu²⁺ was further exploited as an integrated logic system and a specific time-resolved fluorescent “turn-on” assay for simultaneously sensing His and Cys was designed. Meanwhile it can also be used in plasma samples, showing great potential to meet the need of practical application.