Sleep is an inherent property of human beings, and it is mainly associated with the sleep hormone melatonin (MEL). Abnormal levels of MEL can lead to disorders like hypertension, stress, dementia, Alzheimer’s disease, etc. Therefore, continuous monitoring of this hormone is of great concern. In this study, we have developed a sensing platform by combining Nb₂CT_x MXene nanosheets with a zinc-based metal–organic framework (Zn-MOF). The MOF was synthesized using a zinc ion as the metal part and l-glutamic acid as the organic linker. Because the linker itself is a biological molecule, the synthesized MOF can be denoted as bio-MOF as a whole. This novel composite (Zn-MOF-Nb₂CT_x MXene) offers enhanced electrocatalytic properties, improved electrical conductivity, and increased active sites, making it well-suitable for the electrochemical detection of MEL. Notably, the inlay of MOF nanoflakes onto the MXene nanosheets created a synergistic effect that greatly enhanced the electrochemical performance for MEL detection. The sensor made of a Zn-MOF-Nb₂CT_x MXene nanocomposite coated on carbon yarn (CY) exhibited a wide linear detection range for MEL, spanning from 1 to 100 μM, with a detection limit of 215 nM. Importantly, it displayed high selectivity against interfering compounds commonly encountered in body fluids. Also, to check the practical applicability of the sensor, we tried the detection of MEL in biological fluids like sweat, blood serum, and cerebrospinal fluid (CSF) to prove its practicability in real-time medical scenarios. Notably, the use of CY as the electrode material opens the door for its potential integration into a band-aid to make a wearable and point-of-care device for current health sector applications.

中文翻译：

---

生物金属有机框架嵌入式 MXene 纳米复合材料作为可穿戴传感器贴片，用于实时监测睡眠激素

睡眠是人类与生俱来的属性，它主要与睡眠激素褪黑激素（MEL）有关。 MEL水平异常可导致高血压、压力、痴呆、阿尔茨海默病等疾病。因此，对该激素的持续监测值得关注。在这项研究中，我们通过将 Nb ₂ CT _x MXene 纳米片与锌基金属有机框架 (Zn-MOF)相结合开发了一个传感平台。使用锌离子作为金属部分和L-谷氨酸作为有机连接体合成MOF 。由于连接体本身是生物分子，因此合成的MOF可以整体表示为bio-MOF。这种新型复合材料（Zn-MOF-Nb ₂ CT _x MXene）具有增强的电催化性能、改进的导电性和增加的活性位点，使其非常适合 MEL 的电化学检测。值得注意的是，将 MOF 纳米片镶嵌到 MXene 纳米片上产生了协同效应，大大增强了 MEL 检测的电化学性能。该传感器由涂覆在碳纱（CY）上的 Zn-MOF-Nb ₂ CT _x MXene 纳米复合材料制成，对 MEL 表现出较宽的线性检测范围，从 1 到 100 μM，检测限为 215 nM。重要的是，它对体液中常见的干扰化合物表现出高选择性。此外，为了检验传感器的实际适用性，我们尝试检测汗液、血清和脑脊液（CSF）等生物体液中的MEL，以证明其在实时医疗场景中的实用性。值得注意的是，使用 CY 作为电极材料为其集成到创可贴中打开了大门，为当前的卫生部门应用制造可穿戴和护理点设备。