Silica membrane stabilized gold coated silver (Ag@Au) (i.e., internally etched silica coated Ag@Au (IE Ag@Au@SiO₂)) nanoparticles promote surface-enhanced Raman scattering (SERS) activity and detection of uranium(VI) oxide (uranyl) under harsh solution phase conditions including at pH 3–7, with ionic strengths up to 150 mM, and temperatures up to 37 °C for at least 10 hours. These materials overcome traditional solution-phase plasmonic nanomaterial limitations including signal variability and/or degradation arising from nanoparticle aggregation, dissolution, and/or surface chemistry changes. Quantitative uranyl detection occurs via coordination to 3-mercaptopropionate (MPA), a result confirmed through changes in correlated SERS intensities for uranyl and COOH/COO⁻ vibrational modes. Quantification is demonstrated down to 110 nM, a concentration below toxic levels. As pH varies from 3 to 7, the plasmonic properties of the nanoparticles are unchanged, and the uranyl signal depends on both the protonation state of MPA as well as uranyl solubility. High ionic strengths (up to 150 mM) and incubation at 37 °C for at least 10 hours do not impact the SERS activity of uranyl even though slight silica dissolution is observed during thermal treatment. All in all, microporous silica membranes effectively protect the nanoparticles against variations in solution conditions thus illustrating robust tunability for uranyl detection using SERS.

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微孔二氧化硅膜促进等离子体纳米粒子稳定性，用于铀酰的 SERS 检测

二氧化硅膜稳定的镀金银（Ag@Au）（即内部蚀刻二氧化硅涂层的Ag@Au（IE Ag@Au@SiO ₂））纳米粒子促进表面增强拉曼散射（SERS）活性和铀（VI）氧化物的检测（铀酰）在苛刻的溶液相条件下，包括 pH 3-7，离子强度高达 150 mM，温度高达 37 °C 至少 10 小时。这些材料克服了传统的溶液相等离子体纳米材料的局限性，包括由纳米颗粒聚集、溶解和/或表面化学变化引起的信号可变性和/或降解。定量铀酰检测通过与 3-巯基丙酸酯 (MPA) 协调，结果通过铀酰和 COOH/COO ^-振动模式的相关 SERS 强度的变化得到证实。量化证明低至 110 nM，浓度低于毒性水平。当 pH 从 3 到 7 变化时，纳米粒子的等离子体特性不变，铀酰信号取决于 MPA 的质子化状态以及铀酰溶解度。即使在热处理过程中观察到轻微的二氧化硅溶解，高离子强度（高达 150 mM）和在 37 °C 下孵育至少 10 小时不会影响铀酰的 SERS 活性。总而言之，微孔二氧化硅膜有效地保护纳米粒子免受溶液条件变化的影响，从而说明使用 SERS 检测铀酰的稳健可调性。