Herein, we design and synthesize a pH-dependent turn-on fluorescent probe based on the dark resonance energy transfer (DRET) strategy. A silacyclopentadiene (silole) derivative with aggregation-induced emission (AIE) properties is selected as dark energy donor and a rhodamine B derivative with spirocyclic structure as energy acceptor. Attributed to the non-emissive character of silole in solution, fluorescence leakage from the donor is eliminated. Binding with H⁺ turns on the DRET process and energy of donor is converted to the acceptor's fluorescence output before non-radiative decay. The probe responds to pH variation from 2.75 to 5 in buffer solutions with a Stokes shift up to 220 nm. In addition, imaging experiments suggest that the probe is capable of determining pH fluctuations in live cells with good cell membrane permeability and low cytotoxicity.

在本文中，我们基于暗共振能量转移（DRET）策略设计并合成了pH依赖型开启荧光探针。选择具有聚集诱导发射（AIE）性质的硅杂环戊二烯（silole）衍生物作为暗能量供体，选择具有螺环结构的若丹明B衍生物作为能量受体。归因于溶液中硅烷的非发射特性，消除了来自供体的荧光泄漏。与H ⁺结合打开DRET过程，供体的能量在非辐射衰减之前转换为受体的荧光输出。在缓冲溶液中，探针对pH值从2.75到5的变化做出响应，斯托克斯位移最大可达220 nm。此外，成像实验表明该探针能够确定活细胞的pH波动，且细胞膜通透性好且细胞毒性低。