CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China , 96 Jinzhai Road, Hefei, Anhui 230026, China.
ACS Nano. 2015 Jan 27;9(1):761-8. doi: 10.1021/nn5062657. Epub 2014 Dec 30.
Compared to (1)H MRI, (19)F MRI provides higher selectivity but lower sensitivity. Therefore, the need to inject high doses of the (19)F probe to improve its sensitivity for in vivo diagnosis remains a challenge. A "smart" strategy is needed that could locally concentrate a low-dose (19)F probe while avoiding the fast transverse relaxation of the probes. Locally self-assembling and disassembling (19)F nanoparticles may be an optimal measure to achieve this goal. Herein, we report a dual-functional probe 1 for glutathione (GSH)-controlled self-assembly and subsequent caspase 3/7 (Casp3/7)-controlled disassembly of formed nanoparticles (i.e., 1-NPs). Consecutive assembly and disassembly of 1-NPs translate to "off" and "on" (19)F magnetic resonance (MR) signal states, respectively. Employing this smart strategy, we successfully used 1 for the consecutive detection of GSH and Casp3/7 activity in vitro and in cells and imaging Casp3/7 activity in cells and in zebrafish at low doses with a 14.1 T magnetic field.
与 1H MRI 相比，19F MRI 提供了更高的选择性，但灵敏度较低。因此，需要注射高剂量的 19F 探针来提高其体内诊断的灵敏度，这仍然是一个挑战。需要一种“智能”策略，可以局部浓缩低剂量的 19F 探针，同时避免探针的快速横向弛豫。局部自组装和自拆卸 19F 纳米颗粒可能是实现这一目标的最佳措施。在此，我们报告了一种双功能探针 1，用于谷胱甘肽 (GSH) 控制的自组装，以及随后形成的纳米颗粒（即 1-NPs）的 caspase 3/7 (Casp3/7) 控制的拆卸。1-NPs 的连续组装和拆卸分别转化为“关闭”和“开启”（19）F 磁共振（MR）信号状态。采用这种智能策略，我们成功地使用 1 号探针在体外和细胞中连续检测 GSH 和 Casp3/7 活性，并在 14.1 T 磁场下以低剂量在细胞和斑马鱼中成像 Casp3/7 活性。
