Recent advances in plasmonic nanoparticle synthesis have enabled extremely high per-particle surface-enhanced Raman scattering (SERS) efficiencies. This has led to the development of SERS tags for in vivo applications (e.g. tumor targeting and detection), providing high sensitivity and fingerprint-like molecular specificity. While the SERS enhancement factor is a major contributor to SERS tag performance, in practice the throughput and excitation–collection geometry of the optical system can significantly impact detectability. Test methods to objectively quantify SERS particle performance under realistic conditions are necessary to facilitate clinical translation. Towards this goal, we have developed 3D-printed phantoms with tunable, biologically-relevant optical properties. Phantoms were designed to include 1 mm-diameter channels at different depths, which can be filled with SERS tag solutions. The effects of channel depth and particle concentration on the detectability of three different SERS tags were evaluated using 785 nm laser excitation at the maximum permissible exposure for skin. Two of these tags were commercially available, featuring gold nanorods as the SERS particle, while the third tag was prepared in-house using silver-coated gold nanostars. Our findings revealed that the measured SERS intensity of tags in solution is not always a reliable predictor of detectability when applied in a turbid medium such as tissue. The phantoms developed in this work can be used to assess the suitability of specific SERS tags and instruments for their intended clinical applications and provide a means of optimizing new SERS device-tag combination products.

中文翻译：

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3D打印体模用于表征SERS纳米颗粒在混浊介质中的可检测性。

等离子体纳米粒子合成的最新进展已使极高的每粒子表面增强拉曼散射（SERS）效率成为可能。这导致了用于体内应用的SERS标签的开发（例如肿瘤靶向和检测），提供高灵敏度和类似指纹的分子特异性。尽管SERS增强因子是SERS标签性能的主要贡献者，但实际上，光学系统的吞吐量和激发-收集几何形状会显着影响可检测性。在现实条件下客观量化SERS颗粒性能的测试方法对于促进临床翻译十分必要。为了实现这一目标，我们开发了具有可调谐的，与生物相关的光学特性的3D打印体模。幻影被设计为在不同深度包括直径为1毫米的通道，可以用SERS标签解决方案填充。在最大允许皮肤暴露量下，使用785 nm激光激发，评估了通道深度和颗粒浓度对三种不同SERS标签可检测性的影响。这些标签中的两个是可商购的，其特征为金纳米棒作为SERS颗粒，而第三个标签是使用涂银的金纳米星在内部制备的。我们的发现表明，将溶液中标签的SERS强度测量值在应用于混浊介质（例如组织）中时，并不总是可检测性的可靠预测指标。这项工作中开发的模型可以用于评估特定SERS标签和仪器对其预期临床应用的适用性，并提供一种优化新SERS设备标签组合产品的方式。以金纳米棒作为SERS粒子为特征，而第三个标签是使用涂银的金纳米星在内部制备的。我们的发现表明，将溶液中标签的SERS强度测量值在应用于混浊介质（例如组织）中时，并不总是可检测性的可靠预测指标。这项工作中开发的模型可以用于评估特定SERS标签和仪器对其预期临床应用的适用性，并提供一种优化新SERS设备标签组合产品的方式。以金纳米棒作为SERS粒子为特征，而第三个标签是使用涂银的金纳米星在内部制备的。我们的发现表明，将溶液中标签的SERS强度测量值在应用于混浊介质（例如组织）中时，并不总是可检测性的可靠预测指标。这项工作中开发的模型可以用于评估特定SERS标签和仪器对其预期临床应用的适用性，并提供一种优化新SERS设备标签组合产品的方式。