In this work, acid and matrix-tolerant multifunctionalized gold nanoparticles (AuNPs) with an integrated chiral selector towards tyrosine (Tyr) and polyethylenglycol (PEG) chains were developed for visual chiral discrimination of Tyr in biological samples under acid conditions. In brief, AuNPs multifunctionalized with N-acetyl-L-cysteine (NALC) and PEG (PEG/NALC-AuNPs) were prepared via a simple strategy. In the presence of L-Tyr, the color of PEG/NALC-AuNP solution changed from red to gray, while no obvious color change was observed with the introduction of D-Tyr, which indicated that the introduction of PEG onto the surface of AuNPs has no effect on the chiral recognition between L-Tyr and NALC. A computer-aided molecular model was used to clarify the chiral recognition mechanism between NALC and Tyr enantiomers and to further guide the optimization of sensitivity. The resultant PEG/NALC-AuNP sensor presented a significantly improved stability under acid and alkali conditions compared with conventional NALC-AuNPs, resulting in a wider dynamic range (500 nM–100 μM) and a 50 times reduced detection limit by simply adjusting the pH of the sensor system under acid conditions (pH 2–2.5). More importantly, the PEG/NALC-AuNPs can realize the visual chiral discrimination of Tyr enantiomers in biological samples due to their significantly improved long-term stability and reduced interaction towards non-target species.

中文翻译：

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PEG化的NALC官能化的金纳米颗粒，用于手性酪氨酸的比色鉴别。

在这项工作中，开发了具有耐酪氨酸（Tyr）和聚乙二醇（PEG）链的集成手性选择剂的耐酸和耐基质的多功能金纳米颗粒（AuNPs），用于在酸性条件下视觉鉴定生物样品中的Tyr。简而言之，通过简单的策略制备了被N-乙酰基-L-半胱氨酸（NALC）和PEG多功能化的AuNP（PEG / NALC-AuNPs）。在存在L -Tyr的情况下，PEG / NALC-AuNP溶液的颜色从红色变为灰色，而引入D -Tyr则未观察到明显的颜色变化，这表明将PEG引入AuNPs表面对L之间的手性识别没有影响-Tyr和NALC。使用计算机辅助分子模型阐明了NALC和Tyr对映异构体之间的手性识别机理，并进一步指导了灵敏度的优化。与常规的NALC-AuNPs相比，所得的PEG / NALC-AuNP传感器在酸性和碱性条件下具有显着改善的稳定性，从而可通过简单调节pH来实现更大的动态范围（500 nM–100μM）和50倍的检测限在酸性条件下（pH 2-2.5）的传感器系统。更重要的是，PEG / NALC-AuNPs可以实现生物样品中Tyr对映异构体的视觉手性识别，因为它们的长期稳定性显着提高，并且减少了与非目标物种的相互作用。