微波水热法制备Gd3+掺杂的碳量子点型高性能磁共振-荧光双模态分子影像探针

以同时提供钆源和碳源的钆喷酸单葡甲胺为前驱体,利用微波作为加热手段实现分子水平上的搅拌,达到低温、短时间内制得均匀的小粒度Gd³⁺掺杂碳量子点(Gd³⁺/CQDs-MH)的目的。当前驱体在250 ℃下微波水热反应45 min时,获得的Gd³⁺/CQDs-MH表现出较高的量子产率和极强的磁共振性能,避免了传统加热方式对碳量子点的发光能力和弛豫性能极难同时提高的矛盾。该条件下合成出尺寸约1.0 nm的碳量子点,其荧光量子产率为11.0%,Gd³⁺的掺杂质量分数达16.9%,纵向弛豫性能高达4 545.3 mmol^-1·L·s^-1 (Gd³⁺]=0.01 mmol·L^-1)。并且,该碳量子点对HeLa细胞无明显毒性,有望用作高弛豫性能和高发光性能的磁共振-荧光双模态探针。

Synthesis of Magnetic Resonance/Fluorescence Bimodal Molecular Imaging Probe Based on Gadolinium-doped Carbon Quantum Dots by Microwave-hydrothermal Method

Using gadopentetic acid monomeglumine (GdPM) as precursor to provide simultaneously the carbon source and gadolinium (3+) source, gadolinium-doped carbon quantum dots (Gd³⁺/CQDs-MH) with uniformly small size were obtained at a mild condition by microwave hydrothermal method which can realize a molecular level mixing. When GdPM was pyrolyzed under 250 ℃ for 45 min, Gd³⁺/CQDs-MH with high quantum yield (QY) and longitudinal relaxation rate (r₁) were obtained. The contradiction between quantum yield and the relaxation properties has been well balanced, which is very difficult to avoid using traditional heating method. The prepared Gd³⁺/CQDs-MH with an average diameter of about 1.0 nm show little cell toxicity and exhibit a high photoluminescence quantum yield of 11.0%, as well as a high r₁ value of 4 545.3 mmol^-1·L·s^-1 (Gd³⁺]=0.01 mmol·L^-1) with the doping mass fraction of gadolinium (3+) of 16.9%. Therefore, the Gd³⁺/CQDs-MH show big possibility for application in magnetic resonance/fluorescence bimodal molecular imaging.