β-淀粉样蛋白（β-amyloid，Aβ）聚集的检测有助于阿尔茨海默症早期诊断，防止不可逆转的神经损伤发生。目前用于检测Aβ聚集的探针多为荧光探针，而较弱的荧光穿透能力限制了其在生物和组织的成像。19F磁共振成像（MRI）具有更好的穿透力和深度成像能力，能够更精确的检测Aβ聚集。因此我们拟设计、合成一种具有β-淀粉样蛋白靶点的“开-关”型19F MRI探针来检测Aβ聚集。通过RAFT聚合法合成含有磺酸基单糖、氟化物、响应性疏水单体的三嵌段共聚物，然后自组装形成“核壳”结构，使得19F信号微弱和自旋弛豫时间（T2）较短（19F MRI关闭）；Aβ聚集会导致微环境的改变，“核壳”结构发生解体，能够靶向定位于Aβ上，同时使得T2延长，产生强烈的氟信号（19F MRI开启）。该研究开发一种通过微环境改变来检测Aβ聚集的机制，同时为19F MRI技术用于检测Aβ聚集奠定坚实的基础。

ClickDetection of β-amyloid (Aβ) deposition helps early diagnosis of Alzheimer's disease and prevents the occurrence of irreversible nerve damage. The probes detecting Aβ deposition are mostly fluorescent probes which are not perfect for use in biological and tissue imaging due to their limited fluorescence penetration. 19F magnetic resonance imaging (MRI) has better penetration and depth imaging to accurately detect Aβ deposition. Therefore, we plan to design and synthesize an “on-off” 19F MRI probe targeting Aβ to detect Aβ deposition. Triblock copolymers containing sulfonated monosaccharides, fluorides and responsive hydrophobic monomer are synthesized by RAFT polymerization and self-assembly to form a "core-shell" structure leading to weaken 19F signal and shorten the spin relaxation time (T2) (19F MRI OFF). Due to Aβ deposition leading to the changes of the microenvironment, "core-shell" structure is disassembled to target Aβ deposition. It makes T2 prolonged and produces a strong fluoride signal (19F MRI ON). This research can develop a mechanism to detect Aβ deposition through the changes of microenvironment, and make a firm foundation for the technology of 19F MRI to detect Aβ deposition.