Technical Chemistry I, University of Duisburg-Essen and Center for Nanointegration Duisburg-Essen (CENIDE), Universitätsstr. 7, 45141 Essen, Germany.
Bioconjug Chem. 2021 Nov 17;32(11):2439-2446. doi: 10.1021/acs.bioconjchem.1c00468. Epub 2021 Nov 3.
Nano-bio-conjugates, featuring noble metal gold-silver alloy nanoparticles, represent a versatile tool in diagnostics and therapeutics due to their plasmonic and antimicrobial properties tunable by the particle's gold molar fraction. However, little is known about how the binding of thiolated biomolecules to noble metal nanoparticles is influenced by the fraction of gold and silver atoms on the nanoparticle's surface and to which extend this would affect the functionality of the conjugated biomolecules. In this work, we generated gold-silver alloy nanoparticles with average diameters of 7-8 nm using the modern, surfactant-free laser ablation in liquids (LAL) synthesis approach. We conjugated them with thiolated miniStrep aptamer ligands at well-controlled aptamer-to-nanoparticle surface area ratios with maxima between 12 and 27 pmol aptamer/cm particle surface area. The results revealed a clear correlation between surface coverage and the nanoparticles' nominal gold/silver ratio, with maximum coverage reached for gold-rich alloys and a pronounced maximum for silver-rich alloys. However, the conjugates' functionality, evaluated by binding of streptavidin, was surprisingly robust and hardly affected by the nominal composition. However, 1.5 times higher surface coverage was needed to obtain maximum functionality in the silver-rich conjugates. Based on these results, it may be concluded that the nominal composition of gold-silver alloy nano-bioconjugates is freely tunable without a pronounced impact on the attached ligands' functionality, a finding highly relevant for the flexible design of nano-bio-conjugates for future biomedical applications. This study's results may facilitate the design of alloy nano-bio-conjugates for future applications in therapeutics and diagnostics.
纳米-生物缀合物，以金银合金纳米粒子为特色，由于其等离子体和抗菌特性可通过粒子的金摩尔分数进行调节，因此成为诊断和治疗的多功能工具。然而，对于硫醇化生物分子与贵金属纳米粒子的结合如何受到纳米粒子表面的金和银原子分数的影响，以及这将在何种程度上影响共轭生物分子的功能，人们知之甚少。在这项工作中，我们使用现代的无表面活性剂激光烧蚀在液体（LAL）合成方法生成了平均直径为 7-8nm 的金银合金纳米粒子。我们以控制良好的适体-纳米粒子表面积比（最大值为 12-27pmol 适体/cm 粒子表面积）将它们与硫醇化 miniStrep 适体配体缀合。结果表明，表面覆盖率与纳米粒子的名义金/银比之间存在明显的相关性，富金合金达到最大覆盖率，富银合金达到明显的最大值。然而，通过结合链霉亲和素评估的缀合物的功能令人惊讶地稳健，几乎不受名义组成的影响。然而，在富银缀合物中获得最大功能需要 1.5 倍的高表面覆盖率。基于这些结果，可以得出结论，金-银合金纳米-生物缀合物的名义组成可以自由调节，而不会对附着配体的功能产生明显影响，这一发现对于未来生物医学应用中灵活设计纳米-生物缀合物具有重要意义。本研究的结果可能有助于设计用于治疗和诊断的合金纳米-生物缀合物。
