Development of sensitive, selective, and facile electrochemical analytical approaches to monitor tryptophan in different samples is of high significance. For such approaches, efficient electrodes play the key role. Herein, a NiMn-layered double hydroxide (LDH)@poly-l-lysine (PLL) composite has been prepared through in-situ electro-polymerization and further utilized to monitor tryptophan in medicament and biological systems. The as-synthesized NiMn-LDH@PLL composite is highly stable and features a flower-like morphology. It is found that the electron transfer rate of NiMn-LDH@PLL is greatly improved due to the introduction of PLL. The existing Lewis acid—base interaction between LDH and PLL contributes to the increase of unsaturated metal sites and endows this heterojunction composite with high electrocatalytic activity. Especially, the NiMn-LDH (2:1)@PLL composite displays much improved electrochemical response toward tryptophan sensing. This is due to reasonable balance between the outstanding electrocatalytic ability of nickel and the conductivity improvement caused by manganese species. On the other hand, the coordination promotion between NiMn-LDH and PLL is also conducive to improve the sensitivity of electrochemical response. The fabricated sensor exhibits wide linear response in the concentration ranges of 0.1–40 μM and 40–130 μM for tryptophan detection, along with a low detection limit of 52.7 nM. It further displays a high anti-interference ability for tryptophan monitoring even in the presence of other coexistent amino acids and small-sized biological molecules. This study provides a new way to employ LDHs as brilliant sensing platform to ensemble electrochemical sensors for the monitoring of biomolecules.

开发灵敏、选择性和简便的电化学分析方法来监测不同样品中的色氨酸具有重要意义。对于此类方法，高效电极起着关键作用。在此，NiMn 层状双氢氧化物 (LDH)@poly- l-赖氨酸 (PLL) 复合材料已通过原位电聚合制备，并进一步用于监测药物和生物系统中的色氨酸。合成后的 NiMn-LDH@PLL 复合材料非常稳定，具有花状形态。发现由于PLL的引入，NiMn-LDH@PLL的电子传输速率得到了很大的提高。LDH 和 PLL 之间现有的路易斯酸碱相互作用有助于增加不饱和金属位点，并赋予这种异质结复合材料高电催化活性。特别是，NiMn-LDH (2:1)@PLL 复合材料对色氨酸传感的电化学响应有很大改善。这是由于镍出色的电催化能力与锰物种引起的电导率改善之间的合理平衡。另一方面，NiMn-LDH与PLL之间的协调促进也有利于提高电化学响应的灵敏度。制造的传感器在 0.1–40 μM 和 40–130 μM 的浓度范围内表现出广泛的线性响应，用于色氨酸检测，以及 52.7 nM 的低检测限。即使在存在其他共存氨基酸和小尺寸生物分子的情况下，它也显示出对色氨酸监测的高抗干扰能力。这项研究提供了一种将 LDH 作为出色的传感平台来集成电化学传感器以监测生物分子的新方法。1-40 μM 和 40-130 μM 用于色氨酸检测，以及 52.7 nM 的低检测限。即使在存在其他共存氨基酸和小尺寸生物分子的情况下，它也显示出对色氨酸监测的高抗干扰能力。这项研究提供了一种将 LDH 作为出色的传感平台来集成电化学传感器以监测生物分子的新方法。1-40 μM 和 40-130 μM 用于色氨酸检测，以及 52.7 nM 的低检测限。即使在存在其他共存氨基酸和小尺寸生物分子的情况下，它也显示出对色氨酸监测的高抗干扰能力。这项研究提供了一种将 LDH 作为出色的传感平台来集成电化学传感器以监测生物分子的新方法。