Synthesis, Radiolabeling, and In Vivo Imaging of PEGylated High-Generation Polyester Dendrimers
作者:Stuart A. McNelles、Spencer D. Knight、Nancy Janzen、John F. Valliant、Alex Adronov
DOI:10.1021/acs.biomac.5b00911
日期:2015.9.14
A fifth generation aliphatic polyester dendrimer was functionalized with vinyl groups at the periphery and a dipicolylamine Tc(I) chelate at the core. This structure was PEGylated with three different molecular weight mPEGs (mPEG160, mPEG350, and mPEG750) using thiol–ene click chemistry. The size of the resulting macromolecules was evaluated using dynamic light scattering, and it was found that the dendrimer functionalized with mPEG750 was molecularly dispersed in water, exhibiting a hydrodynamic diameter of 9.2 ± 2.1 nm. This PEGylated dendrimer was subsequently radiolabeled using [99mTc(CO)3(H2O)3]+ and purified to high (>99%) radiochemical purity. Imaging studies were initially performed on healthy rats to allow comparison to previous Tc-labeled dendrimers and then on xenograft murine tumor models, which collectively showed that the dendrimers circulated in the blood for an extended period of time (up to 24 h). Furthermore, the radiolabeled dendrimer accumulated in H520 xenograft tumors, which could be visualized by single-photon emission computed tomography (SPECT). The reported PEGylated aliphatic polyester dendrimers represent a new platform for developing tumor-targeted molecular imaging probes and therapeutics.
第五代脂肪族聚酯树枝状聚合物的外围是乙烯基官能化,核心是二二甲胺锝(I)螯合物。利用硫醇-烯点击化学法,用三种不同分子量的 mPEG(mPEG160、mPEG350 和 mPEG750)对这种结构进行了 PEG 化。使用动态光散射法评估了所得大分子的尺寸,发现用 mPEG750 进行官能化的树枝状聚合物在水中呈分子分散状态,其水动力直径为 9.2 ± 2.1 nm。这种 PEG 化树枝状聚合物随后用 [99mTc(CO)3(H2O)3]+ 进行了放射标记,并纯化到了很高的放射化学纯度(>99%)。首先在健康大鼠身上进行了成像研究,以便与以前的锝标记树状分子进行比较,然后在异种移植小鼠肿瘤模型上进行了成像研究,结果表明树状分子在血液中循环的时间较长(长达 24 小时)。此外,放射性标记的树枝状聚合物在H520异种移植肿瘤中积累,可通过单光子发射计算机断层扫描(SPECT)观察到。所报道的 PEG 化脂肪族聚酯树枝状聚合物是开发肿瘤靶向分子成像探针和疗法的新平台。