Fluorescent Detection of Cu(Ⅱ) by Chitosan-based AIE Bioconjugate

【摘要】 Detection of Cu（Ⅱ） is very important in disease diagnose, biological system detection and environmental monitoring. Previously, we found that the product TPE-CS prepared by attaching the chromophores of tetraphenylethylene（TPE） to the chitosan（CS） chains showed excellent fluorescent properties. In this study, we tried to use TPE-CS for detecting Cu（Ⅱ） because of the stable complexation of CS with heavy metals and the luminosity mechanism of the Restriction of Intramolecular Rotations（RIR） for aggregation-induced emission（AIE）-active materials. The fluorescence intensity changed when TPE-CS was contacted with different metal ions, to be specific, no change for Na⁺, slightly increase for Hg²⁺, Pb²⁺, Zn²⁺, Cd²⁺, Fe²⁺, Fe³⁺ due to the RIR caused by the complexation between CS and metal ions. However, for Cu²⁺, an obvious fluorescence decrease was observed because of the Photoinduced-Electron-Transfer（PET）. Moreover, we found that the quenched FL intensity of TPE-CS was proportional to the concentration of Cu（Ⅱ） in the range of 5 μmol/L to 100 μmol/L, which provided a new way to quantitatively detect Cu（Ⅱ） . Besides, TPE-CS has excellent water-solubility as well as absorbability（the percentage of removal, R = 84%）, which is an excellent detection probe and remover for Cu（Ⅱ） .更多还原

【Abstract】 Detection of Cu（Ⅱ） is very important in disease diagnose, biological system detection and environmental monitoring. Previously, we found that the product TPE-CS prepared by attaching the chromophores of tetraphenylethylene（TPE） to the chitosan（CS） chains showed excellent fluorescent properties. In this study, we tried to use TPE-CS for detecting Cu（Ⅱ） because of the stable complexation of CS with heavy metals and the luminosity mechanism of the Restriction of Intramolecular Rotations（RIR） for aggregation-induced emission（AIE）-active materials. The fluorescence intensity changed when TPE-CS was contacted with different metal ions, to be specific, no change for Na⁺, slightly increase for Hg²⁺, Pb²⁺, Zn²⁺, Cd²⁺, Fe²⁺, Fe³⁺ due to the RIR caused by the complexation between CS and metal ions. However, for Cu²⁺, an obvious fluorescence decrease was observed because of the Photoinduced-Electron-Transfer（PET）. Moreover, we found that the quenched FL intensity of TPE-CS was proportional to the concentration of Cu（Ⅱ） in the range of 5 μmol/L to 100 μmol/L, which provided a new way to quantitatively detect Cu（Ⅱ） . Besides, TPE-CS has excellent water-solubility as well as absorbability（the percentage of removal, R = 84%）, which is an excellent detection probe and remover for Cu（Ⅱ） .更多还原