Rational Design, Synthesis of Fluorescence Probes for Quantitative Detection of Amyloid-ß in Alzheimer's Disease Based on Rhodamine-Metal Complex.

The efficient detection and monitoring of amyloid-ß plaques (Aß42) can greatly promote the diagnosis and therapy of Alzheimer's disease (AD). Fluorescence imaging is a promising method for this, but the accurate determination of Aß42 still remains a challenge. The development of a reliable fluorescent probe to detect Aß42 is essential. Herein, we report a rational design strategy for Aß42 fluorescence probes based on rhodamine-copper complexes, Rho1-Cu-Rho4-Cu, among them Rho4-Cu exhibits the best performance including high sensitivity (detection limit = 24 nM), high affinity (Kd = 23.4 nM), and high selectivity; hence, Rho4-Cu is selected for imaging Aß42 in AD mice, and the results showed that this probe can differentiate normal mice and AD mice effectively.