Lanthanide Functionalized Metal-Organic Coordination Polymer: Toward Novel Turn-On Fluorescent Sensing of Amyloid β-Peptide.

Metal-organic coordination polymers (MOCPs) have been emerging as very attractive nanomaterials due to their tunable nature and diverse applications. Herein, using Tb3+ as the luminescence center, 1,3,5-benzenetricarboxylate (BTC) as building block and Cu2+ as the signal modulator as well as a recognition unit, we propose a novel and effective lanthanide functionalized MOCP (LMOCP) fluorescent sensor (Cu-BTC/Tb) for amyloid β-peptide (Aβ) monomer, a biomarker for Alzheimer disease (AD). Specifically, Cu-BTC/Tb, created by postsynthesis modification strategy under room temperature, is almost nonemissive due to the quenching effect of Cu2+ in the MOCP, exhilaratingly, the presence of Aβ1-40 triggered a significant emission enhancement of Cu-BTC/Tb assay due to the high binding affinity of Aβ1-40 for Cu2+ and the subsequent suppression of the quenching effect. In the assay, this LMOCP sensor shows high sensitivity with detection limit of 0.3 nM. Due to its capability to eliminate autofluorescence, Cu-BTC/Tb was also applied to the time-gated detection of Aβ1-40 in human plasma with promising results. This work presents a novel strategy for the construction of functional luminescent LMOCP for sensitively turn-on fluorescent sensing of Aβ1-40. We believe the proposed strategy would inspire the development of various LMOCP-based fluorescent assays or medical imaging platforms for advanced biological implementations.