Here, we report on progress made in coupling advances in surface-enhanced Raman scattering (SERS) techniques with a deep-ocean deployable Raman spectrometer. Our SERS capability is provided by development of a Cu foam-loaded silver-nanobean (Ag/Cu foam) which we have successfully coupled to the tip of a Raman probe head capable of insertion into deep-sea sediments and associated fluids. Our purpose is to expand the range of molecular species which can be detected in deep-sea biogeochemical environments, and our initial targets are a series of amino acids reportedly found in pore waters of seep locations. Our work has progressed to the point of a full dock-based end-to-end test of the essential ship tether-ROV-deep-sea Raman system. We show here the initial results from this test as the essential requirement before at sea full ocean depth deployment. We describe in detail the procedures for preparing the Ag/Cu foam bean and demonstrate in our end-to-end test that this, when coupled to the spectrometer probe tip, yields a SERS signal enhancement of 1.2 × 10⁶ for test molecules and detection of amino acids at 10^–6 M levels consistent with reported levels of natural occurrence. Each nanobean unit is for single-use sensing since invasion of the sample fluid into the Ag/Cu foam matrix is not reversible. We describe techniques for bean rotation/replacement at depth to allow for multiple analyses at several locations during each ROV dive.

中文翻译：

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基于银纳米豆/铜泡沫的新型SERS探针用于深海极端环境生物分子检测


在这里，我们报告了表面增强拉曼散射（SERS）技术与深海可部署拉曼光谱仪相结合所取得的进展。我们的 SERS 能力是通过开发加载铜泡沫的银纳米豆（Ag/Cu 泡沫）来提供的，我们已将其成功耦合到能够插入深海沉积物和相关流体的拉曼探头的尖端。我们的目的是扩大可在深海生物地球化学环境中检测到的分子种类的范围，我们的初步目标是据报道在渗漏位置的孔隙水中发现的一系列氨基酸。我们的工作已经进展到对重要的船舶系绳-ROV-深海拉曼系统进行完整的基于码头的端到端测试。我们在此展示该测试的初步结果，作为海上全海洋深度部署之前的基本要求。我们详细描述了制备银/铜泡沫豆的程序，并在我们的端到端测试中证明，当与光谱仪探头尖端耦合时，会产生 1.2 × 10 ⁶ 用于测试分子并检测 10 ^–6 M 水平的氨基酸，与报告的自然发生水平一致。每个纳米豆单元都是一次性传感，因为样品流体侵入银/铜泡沫基质是不可逆的。我们描述了在深度进行 bean 旋转/更换的技术，以便在每次 ROV 潜水期间在多个位置进行多次分析。