In this work, a novel non-enzymatic superoxide anion (O₂•⁻) sensor was constructed based on Ag nanoparticles (NPs) / poly (amidoamine) (PAMAM) dendrimers and used to investigate the dynamic process of O₂•⁻ release from living cells. The AgNPs/PAMAM nanohybrids were characterized by transmission electron microscopy (TEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The fabricated electrode exhibited excellent catalytic activity toward the reaction of O₂•⁻ with a super low detection limit (LOD) of 2.530 × 10^–13 M (S/N = 3) and wide linear range of 8 orders of magnitude. It could fulfill the requirement of real-time measurement O₂•⁻ released from living cells. Furthermore, zymosan was chosen as the stimulant to induce O₂•⁻ generation from cancer cells (rat adrenal medulla pheochromocytoma cell (PC12)). The electrochemical experiment results indicated that the levels of intracellular O₂•⁻ depended on the amount of Zymosan. A large amount of O₂•⁻ generated in the living cells by added heavy stimulant could damage cells seriously. More importantly, a vitro simulation experiment confirmed the role of superoxide dismutase (SOD) for the first time because it could maintain the O₂•⁻ concentration at a normal physiological range. These findings are of great significance for evaluating the metabolic processes of O₂•⁻ in the biological system, and this work has the tremendous potential application in clinical diagnostics to assess oxidative stress.

在这项工作中，一种新颖的非酶超氧阴离子（O ₂ • ^- ）传感器是基于银纳米颗粒（NP）/聚（酰氨基胺）（PAMAM）树枝状聚合物和用于研究的O-动态过程构造₂ • ^-释放从活细胞。AgNPs / PAMAM纳米杂化物通过透射电子显微镜（TEM），循环伏安法（CV）和电化学阻抗谱（EIS）进行了表征。制成的电极对O ₂ • ^-的反应具有优异的催化活性，超低检测限（LOD）为2.530×10 – ¹³  M（S / N = 3），线性范围宽达8个数量级。可以满足实时测量的要求₂ • ^-从活细胞释放。此外，选择酵母聚糖作为刺激物来诱导癌细胞（大鼠肾上腺髓质嗜铬细胞瘤细胞（PC12））产生O ₂ • ^-。电化学实验结果表明，细胞内O ₂ • ^-的水平取决于酵母聚糖的含量。加入重度刺激剂会在活细胞中产生大量O ₂ • ^-，从而严重破坏细胞。更重要的是，一项体外模拟实验首次证实了超氧化物歧化酶（SOD）的作用，因为它可以维持O ₂ • ^-在正常生理范围内的浓度。这些发现对评估生物系统中O ₂ • ^-的代谢过程具有重要意义，这项工作在评估氧化应激的临床诊断中具有巨大的潜在应用价值。