Owing to their electromagnetic properties, tunability and biocompatibility, gold nanorods are being investigated as multifunctional probes for a range of biomedical applications. However, detection beyond the reach of traditional fluorescence and two-photon approaches and quantitation of their concentration in biological tissue remain challenging tasks in microscopy. Here, we show how the size and aspect ratio that impart gold nanorods with their plasmonic properties also make them a source of entropy. We report on how depolarization can be exploited as a strategy to visualize gold nanorod diffusion and distribution in biologically relevant scenarios ex vivo, in vitro and in vivo. We identify a deterministic relation between depolarization and nanoparticle concentration. As a result, some of the most stringent experimental conditions can be relaxed, and susceptibility to artefacts is reduced, enabling microscopic and macroscopic applications.

中文翻译：

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去极化签名可绘制生物组织内的金纳米棒

由于其电磁性能，可调性和生物相容性，金纳米棒已被研究为多功能探针，可用于一系列生物医学应用。然而，在显微镜下，传统荧光和双光子方法无法检测以及它们在生物组织中的浓度定量仍然是一项艰巨的任务。在这里，我们展示了赋予金纳米棒具有等离激元特性的尺寸和长宽比如何使它们成为熵的来源。我们报告了如何利用去极化作为一种​​策略来可视化金纳米棒在离体，离体和体内生物学相关场景中的扩散和分布。我们确定去极化和纳米粒子浓度之间的确定性关系。结果，可以放宽一些最严格的实验条件，并减少对伪影的敏感性，从而可以进行微观和宏观应用。