Shan Fengyuan, Panariello Luca, Wu Gaowei, Gavriilidis Asterios, Fielding Helen H, Parkin Ivan P
Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
Department of Chemical Engineering, University College London Torrington Place London WC1E 7JE UK.
RSC Adv. 2021 May 14;11(29):17694-17703. doi: 10.1039/d1ra03459f. eCollection 2021 May 13.
The interaction of methylene blue and crystal violet dyes with a range of gold nanoparticles (AuNPs), gold nanoclusters and gold/silver nanoclusters is reported. It is found that 20 nm citrate-capped AuNPs have strong interactions with these two dyes that result in red-shifted absorption peaks in their electronic absorption spectra. Transmission electron microscopy and dynamic light scattering measurements show that this can be attributed to these AuNPs combining into large agglomerates. Eventually, precipitation is observed. The agglomeration process is triggered when the dye reaches or exceeds a threshold concentration and then does not stop until all the AuNPs have agglomerated into large particles and precipitated. Calculations suggest that the threshold concentration corresponds to having sufficient dye molecules to form a monolayer on the surface of AuNPs. We also observe similar red-shifting in the absorption peaks of the electronic absorption spectra of 11-50 nm citrate-capped AuNPs formed by both single step and seeded growth methods. No such interactions were observed in the UV-vis spectra of the dyes with Tris-capped AuNPs, gold nanoclusters or gold/silver nanoclusters.
报道了亚甲蓝和结晶紫染料与一系列金纳米颗粒（AuNP）、金纳米簇和金/银纳米簇的相互作用。发现20nm柠檬酸盐包覆的AuNP与这两种染料有强烈的相互作用，导致它们的电子吸收光谱中的吸收峰发生红移。透射电子显微镜和动态光散射测量表明，这可归因于这些AuNP结合形成大的团聚体。最终，观察到沉淀。当染料达到或超过阈值浓度时，团聚过程被触发，然后一直持续到所有AuNP都团聚成大颗粒并沉淀。计算表明，阈值浓度对应于有足够的染料分子在AuNP表面形成单分子层。我们还观察到通过单步和种子生长方法形成的11 - 50nm柠檬酸盐包覆的AuNP的电子吸收光谱的吸收峰有类似的红移。在染料与三（羟甲基）氨基甲烷包覆的AuNP、金纳米簇或金/银纳米簇的紫外 - 可见光谱中未观察到此类相互作用。
