Chemistry Department, Shiraz University, Shiraz, 71454, Iran.
Department of Chemistry, Razi University Kermanshah, Iran.
Lab Chip. 2023 Aug 22;23(17):3837-3849. doi: 10.1039/d3lc00424d.
Simultaneous detection of multiple amino acids (AAs) instead of individual AAs is inherently worthwhile for improving diagnostic accuracy in clinical applications. Here, a facile and reliable colorimetric microfluidic paper-based analytical device (μPAD) using carbon dots doped with transition metals (Cr, Mn, Fe, Co, Ni, Cu, and Zn) has been provided to detect and discriminate 20 natural amino acids. To make the colourless metal-doped carbon dots suitable for colorimetric assays, they were mixed with ninhydrin to form a charge transfer complex. This optical tongue system, which was constructed by dropping mixtures of ninhydrin with a series of metal-doped carbon dots on a paper substrate in an array format, represented obvious but different colorimetric signatures for every examined amino acid. Since bovine serum albumin was used as a chiral selector reagent for synthesizing the CDs, the sensor device represented excellent selectivity to identify enantiomeric species of AAs. This is the first optical array device that can simultaneously discriminate AAs and several of their enantiomers. We employed various statistical and chemometric methods to analyze the digital data library collected by Image J software, including principal component analysis (PCA), linear discriminant analysis (LDA), and hierarchical cluster analysis (HCA). Twenty AAs could be well distinguished at various concentrations (10.00, 5.00, 2.50, and 1.25 mM). The colorimetric patterns were highly repeatable and were characteristic of individual AAs. Besides qualitative analysis, the designed μPAD-based optical tongue represented quantitative analysis ability, , for lysine in the concentration ranges of 0.005-20.0 mM with a detection limit of 1.0 × 10 M and for arginine in the concentration range of 0.12-20.00 mM with a detection limit of 80.0 × 10 M. In addition, the binary, ternary, and quaternary mixtures of AAs could also be well recognized with this sensor.
同时检测多种氨基酸（AA）而不是单个 AA，对于提高临床应用中的诊断准确性具有重要意义。在这里，我们提供了一种简单可靠的比色微流控纸基分析装置（μPAD），该装置使用掺杂过渡金属（Cr、Mn、Fe、Co、Ni、Cu 和 Zn）的碳点来检测和区分 20 种天然氨基酸。为了使无色的金属掺杂碳点适用于比色分析，将它们与邻苯二醛混合形成电荷转移复合物。该光学舌系统通过将邻苯二醛与一系列金属掺杂碳点的混合物以阵列格式滴在纸基底上构建，为每种被检测的氨基酸提供了明显但不同的比色特征。由于牛血清白蛋白被用作合成 CD 的手性选择试剂，因此该传感器装置对 AA 的对映异构体表现出优异的选择性。这是第一个可以同时区分 AA 和它们的几种对映异构体的光学阵列装置。我们使用各种统计和化学计量学方法来分析由 Image J 软件收集的数字数据库，包括主成分分析（PCA）、线性判别分析（LDA）和层次聚类分析（HCA）。在各种浓度（10.00、5.00、2.50 和 1.25 mM）下，20 种 AA 可以得到很好的区分。比色模式具有高度重复性，且具有单个 AA 的特征。除了定性分析，基于设计的 μPAD 的光学舌还具有定量分析能力，用于检测 0.005-20.0 mM 浓度范围内的赖氨酸，检测限为 1.0×10 M，用于检测 0.12-20.00 mM 浓度范围内的精氨酸，检测限为 80.0×10 M。此外，该传感器还可以很好地识别二元、三元和四元混合物的 AA。
