Li Kei Kwan, He Jianlong, Huang Qijia, Kinoshita Seth, Ding Yong, Xia Younan
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Precis Chem. 2025 Mar 29;3(5):272-278. doi: 10.1021/prechem.4c00105. eCollection 2025 May 26.
Gold nanospheres with uniform sizes greater than 30 nm are essential to quantitative lateral flow immunoassays for the rapid detection of pathogens such as viruses, bacteria, and fungi. However, scaling up their synthesis for commercial applications remains challenging due to the necessity to introduce the precursor dropwise. Herein, we report the synthesis of Au cubes with an edge length of 30 nm using one-shot injection of the precursor, followed by aging to transform the cubes into uniform spheres of 35 nm in diameter. Our mechanistic study based on qualitative and quantitative analyses using surface-enhanced Raman scattering and inductively coupled plasma mass spectrometry, respectively, suggests that Br desorption from the surface of Au nanocubes at an elevated temperature was responsible for the shape transformation by inducing oxidative etching and atomic migration in the outermost layer. By eliminating the need for dropwise addition, this protocol is well-suited for the mass production of Au nanospheres in a continuous flow reactor for future incorporation into quantitative point-of-care sensors.
尺寸大于30 nm且大小均匀的金纳米球对于用于快速检测病毒、细菌和真菌等病原体的定量侧向流动免疫分析至关重要。然而，由于需要逐滴引入前驱体，扩大其合成规模以用于商业应用仍然具有挑战性。在此，我们报告了通过一次性注射前驱体合成边长为30 nm的金立方体，随后进行老化处理，将立方体转变为直径35 nm的均匀球体。我们分别基于表面增强拉曼散射和电感耦合等离子体质谱的定性和定量分析进行的机理研究表明，在升高的温度下，溴从金纳米立方体表面解吸，通过诱导最外层的氧化蚀刻和原子迁移导致了形状转变。通过消除逐滴添加的需要，该方案非常适合在连续流动反应器中大规模生产金纳米球，以便将来纳入定量即时护理传感器中。
