Bimodal systems for nuclear and optical imaging are currently being intensively investigated due to their comparable detection sensitivity and the complementary information they provide. In this perspective, we have implemented both modalities on biocompatible ultrasmall silicon nanoparticles (Si NPs). Such nanoparticles are particularly interesting since they are highly biocompatible, have covalent surface functionalization and demonstrate very fast body clearance. We prepared monodisperse citrate-stabilized Si NPs (2.4 ± 0.5 nm) with more than 40 accessible terminal amino groups per particle and, for the first time, simultaneously, a near-infrared dye (IR800-CW) and a radiolabel (⁶⁴Cu-NOTA = 1,4,7-triazacyclononane-1,4,7-triacetic acid) have been covalently linked to the surface of such Si NPs. The obtained nanomaterials have been fully characterized using HR-TEM, XPS, UV-Vis and FT-IR spectroscopy. These dual-labelled particles do not exhibit any cytotoxicity in vitro. In vivo studies employing both positron emission tomography (PET) and optical imaging (OI) techniques revealed rapid renal clearance of dual-labelled Si NPs from mice.

中文翻译：

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超小硅纳米颗粒作为多模态成像的有前途的平台。

由于具有可比的检测灵敏度和它们提供的补充信息，目前正在对用于核成像和光学成像的双峰系统进行深入研究。从这个角度来看，我们已经在生物相容性超小硅纳米颗粒（Si NPs）上实现了两种模式。这样的纳米颗粒特别令人感兴趣，因为它们具有高度的生物相容性，具有共价表面功能化并显示出非常快的清除率。我们制备了单分散的柠檬酸盐稳定的Si NPs（2.4±0.5 nm），每个颗粒具有40多个可接近的末端氨基，并且首次同时制备了近红外染料（IR800-CW）和放射性标记（⁶⁴Cu-NOTA ＝ 1,4,7-三氮杂环壬烷-1,4,7-三乙酸）已共价连接至此类Si NP的表面。所获得的纳米材料已使用HR-TEM，XPS，UV-Vis和FT-IR光谱进行了全面表征。这些双重标记的颗粒在体外不表现出任何细胞毒性。使用正电子发射断层扫描（PET）和光学成像（OI）技术的体内研究表明，双标记的Si NPs从小鼠中可快速清除肾脏。