Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX 75080, USA.
Department of Mechanical Engineering, The University of Texas at Dallas, Richardson, TX 75080, USA.
Molecules. 2024 May 21;29(11):2416. doi: 10.3390/molecules29112416.
Fluorescent gold nanoclusters (AuNCs) have shown promise as metal ion sensors. Further research into surface ligands is crucial for developing sensors that are both selective and sensitive. Here, we designed simple tripeptides to form fluorescent AuNCs, capitalizing on tyrosine's reduction capability under alkaline conditions. We investigated tyrosine's role in both forming AuNCs and sensing metal ions. Two tripeptides, tyrosine-cysteine-tyrosine (YCY) and serine-cysteine-tyrosine (SCY), were used to form AuNCs. YCY peptides produced AuNCs with blue and red fluorescence, while SCY peptides produced blue-emitting AuNCs. The blue fluorescence of YCY- and SCY-AuNCs was selectively quenched by Fe and Cu, whereas red-emitting YCY-AuNC fluorescence remained stable with 13 different metal ions. The number of tyrosine residues influenced the sensor response. DLS measurements revealed different aggregation propensities in the presence of various metal ions, indicating that chelation between the peptide and target ions led to aggregation and fluorescence quenching. Highlighting the innovation of our approach, our study demonstrates the feasibility of the rational design of peptides for the formation of fluorescent AuNCs that serve as highly selective and sensitive surface ligands for metal ion sensing. This method marks an advancement over existing methods due to its dual capability in both synthesizing gold nanoclusters and detecting analytes, specifically Fe and Cu.
荧光金纳米团簇 (AuNCs) 已显示出作为金属离子传感器的潜力。进一步研究表面配体对于开发既具有选择性又具有灵敏度的传感器至关重要。在这里，我们设计了简单的三肽来形成荧光 AuNCs，利用酪氨酸在碱性条件下的还原能力。我们研究了酪氨酸在形成 AuNCs 和感测金属离子中的作用。两种三肽，酪氨酸-半胱氨酸-酪氨酸 (YCY) 和丝氨酸-半胱氨酸-酪氨酸 (SCY)，用于形成 AuNCs。YCY 肽产生具有蓝色和红色荧光的 AuNCs，而 SCY 肽产生蓝色发射的 AuNCs。YCY 和 SCY-AuNC 的蓝色荧光被 Fe 和 Cu 选择性猝灭，而红色发射的 YCY-AuNC 荧光在 13 种不同金属离子存在下保持稳定。酪氨酸残基的数量影响传感器的响应。DLS 测量表明在存在各种金属离子时存在不同的聚集倾向，表明肽与靶离子之间的螯合导致聚集和荧光猝灭。突出了我们方法的创新性，我们的研究表明，合理设计用于形成荧光 AuNCs 的肽作为金属离子传感的高度选择性和灵敏的表面配体是可行的。与现有方法相比，该方法具有双重优势，既能合成金纳米簇，又能检测分析物，特别是 Fe 和 Cu。
