In this work, stable and catalytically active copper ferrite nanodots (CuFe₂O₄) entrapped by porous RGO nanosheets were prepared via a facile condensation process using a green reducing agent. The composite was characterized by HR-TEM, EDX, XRD, Raman, TGA, and electrochemical methods. Oxidative stress caused by the imbalance between oxidants and antioxidant defenses is implicated in many pathological conditions including age-related disorders, cancer, and cardiovascular, inflammatory, neurodegenerative and neuropsychiatric diseases. 3-Nitrotyrosine is an electrochemically active biomarker of oxidative stress; hence its electrochemical determination is useful to set up a sensitive analytical tool for oxidative stress measurement. The electrocatalytic activities of a CuFe₂O₄@RGO composite modified electrode toward 3-nitrotyrosine were studied in detail. A rapid, sensitive, selective and reproducible electrochemical sensing platform was developed for the detection and quantification of 3-nitrotyrosine under neutral pH conditions. Remarkably, the limit of detection was found to be 25.14 pM, which surpassed the detection limits of many existing analytical methods. The practical applicability of the method was demonstrated in human urine and blood serum samples.

中文翻译：

---

分层结构的CuFe ₂ O ₄ ND @ RGO复合材料用于检测生物流体中的氧化应激生物标志物

在这项工作中，通过多孔RGO纳米片包埋了稳定的具有催化活性的铜铁氧体纳米点（CuFe ₂ O ₄）。使用绿色还原剂的简便冷凝过程。通过HR-TEM，EDX，XRD，拉曼，TGA和电化学方法对复合材料进行了表征。由氧化剂和抗氧化剂防御之间的不平衡引起的氧化应激与许多病理状况有关，包括与年龄有关的疾病，癌症以及心血管，炎性，神经退行性疾病和神经精神疾病。3-硝基酪氨酸是氧化应激的电化学活性生物标志物；因此，其电化学测定对于建立用于氧化应力测量的灵敏分析工具很有用。CuFe ₂ O ₄的电催化活性研究了RGO复合修饰电极对3-硝基酪氨酸的作用。开发了一种快速，灵敏，选择性和可重现的电化学传感平台，用于在中性pH条件下检测和定量3-硝基酪氨酸。值得注意的是，检测限为25.14 pM，超过了许多现有分析方法的检测限。该方法在人尿液和血清样品中得到了实际应用。