Liu Zihao, Li Xingxing, Masai Hiroshi, Huang Xinyi, Tsuda Susumu, Terao Jun, Yang Jinlong, Guo Xuefeng
Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China.
Hefei National Laboratory for Physics Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
Sci Adv. 2021 Mar 3;7(10). doi: 10.1126/sciadv.abe4365. Print 2021 Mar.
One of the ultimate goals of analytic chemistry is to efficiently discriminate between amino acids. Here we demonstrate this ability using a single-molecule electrical methodology based on molecular nanocircuits formed from stable graphene-molecule-graphene single-molecule junctions. These molecular junctions are fabricated by covalently bonding a molecular machine featuring a permethylated-β-cyclodextrin between a pair of graphene point contacts. Using pH to vary the type and charge of the amino acids, we find distinct multimodal current fluctuations originating from the different host-guest interactions, consistent with theoretical calculations. These conductance data produce characteristic dwell times and shuttling rates for each amino acid, and allow accurate, statistical real-time, in situ measurements. Testing four amino acids and their enantiomers shows the ability to distinguish between them within a few microseconds, thus paving a facile and precise way to amino acid identification and even single-molecule protein sequencing.
分析化学的最终目标之一是高效地区分氨基酸。在此，我们展示了利用基于由稳定的石墨烯-分子-石墨烯单分子结形成的分子纳米电路的单分子电学方法实现这一能力。这些分子结是通过在一对石墨烯点接触之间共价连接一个具有全甲基化-β-环糊精的分子机器来制备的。利用pH值改变氨基酸的类型和电荷，我们发现了源自不同主客体相互作用的独特多峰电流波动，这与理论计算结果一致。这些电导数据为每种氨基酸产生了特征性的驻留时间和穿梭速率，并允许进行准确的、统计实时的原位测量。对四种氨基酸及其对映体进行测试表明，能够在几微秒内区分它们，从而为氨基酸鉴定乃至单分子蛋白质测序开辟了一条简便而精确的途径。
