A facile, straightforward, and low-cost method is proposed to synthesize gold@silver@gold core double-shell nanoparticles. The technique is a seed-mediated growth protocol that contains four steps of (1) gold seed synthesis, (2) gold seed growth, (3) silver layer coating through silver salt reduction, and (4) gold layer deposition via gold precursor reduction. The prepared nanoparticles had a narrow size distribution and the average particle size of 28 ± 1 nm. Cysteine was introduced to the nanoparticles solution as a coupling agent to assemble nanoparticles. Aggregation-induced two-photon photoluminescence enhancement of three types assembled nanoparticles, i.e., gold@silver@gold, gold@silver, and gold nanoparticles, was studied. It was observed that the assembled core double-shell nanoparticles presented huge enhancement in two-photon photoluminescence signal in comparison with two other nanoparticles. Moreover, the gold@silver@gold nanoparticle is a stable and biocompatible plasmonic nanosystem. This paper provides a novel candidate for two-photon photoluminescence excitation sensing and imaging for biomedical applications.

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金@银@金核双壳纳米粒子：合成和聚集增强的双光子光致发光评估

提出了一种简便，直接，低成本的方法来合成金@银@金核双壳纳米粒子。该技术是种子介导的生长方案，包含四个步骤：（1）金种子合成，（2）金种子生长，（3）通过银盐还原形成银层涂层和（4）通过金前体还原形成金层。制备的纳米颗粒具有窄的尺寸分布，平均粒径为28±1nm。将半胱氨酸作为偶联剂引入纳米颗粒溶液以组装纳米颗粒。研究了三种类型的组装纳米粒子，即金@银@金，金@银和金纳米粒子的聚集诱导的双光子光致发光增强。观察到组装的核心双壳纳米粒子与其他两个纳米粒子相比，在两个光子光致发光信号中呈现出极大的增强。此外，gold @ silver @ gold纳米粒子是一种稳定且生物相容的等离子体纳米系统。本文为生物医学应用中的双光子光致发光激发传感和成像提供了一种新颖的候选方法。