Albumin-Mediated Biomineralization of Paramagnetic NIR Ag2S QDs for Tiny Tumor Bimodal Targeted Imaging in Vivo

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• 作者：Jing Zhang ; Guangyu Hao ; Chenfei Yao ; Jiani Yu ; Jun Wang ; Weitao Yang ; Chunhong Hu ; Bingbo Zhang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：July 6, 2016
• 年：2016
• 卷：8
• 期：26
• 页码：16612-16621
• 全文大小：670K
• 年卷期：0
• ISSN：1944-8252

文摘

Bimodal imaging has captured increasing interests due to its complementary characteristics of two kinds of imaging modalities. Among the various dual-modal imaging techniques, MR/fluorescence imaging has been widely studied owing to its high 3D resolution and sensitivity. There is, however, still a strong demand to construct biocompatible MR/fluorescence contrast agents with near-infrared (NIR) fluorescent emissions and high relaxivities. In this study, BSA-DTPA^Gd derived from bovine serum albumin (BSA) as a novel kind of biotemplate is employed for biomineralization of paramagnetic NIR Ag₂S quantum dots (denoted as Ag₂S@BSA-DTPA^Gd pQDs). This synthetic strategy is found to be bioinspired, environmentally benign, and straightforward. The obtained Ag₂S@BSA-DTPA^Gd pQDs have fine sizes (ca. 6 nm) and good colloidal stability. They exhibit unabated NIR fluorescent emission (ca. 790 nm) as well as high longitudinal relaxivity (r₁ = 12.6 mM^–1 s^–1) compared to that of commercial Magnevist (r₁ = 3.13 mM^–1 s^–1). In vivo tumor-bearing MR and fluorescence imaging both demonstrate that Ag₂S@BSA-DTPA^Gd pQDs have pronounced tiny tumor targeting capability. In vitro and in vivo toxicity study show Ag₂S@BSA-DTPA^Gd pQDs are biocompatible. Also, biodistribution analysis indicates they can be cleared from body mainly via liver metabolism. This protein-mediated biomineralized Ag₂S@BSA-DTPA^Gd pQDs presents great potential as a novel bimodal imaging contrast agent for tiny tumor diagnosis.