Increased oxidative burden contributes to the pathogenesis of most inflammatory diseases and is associated with aging and chronic inflammation. Macrophages contribute to the generation of reactive oxygen species (ROS) within inflamed tissues. Currently, ROS generation is measured using fluorescent probes and colorimetric/fluorimetric biochemical assays. Hydrogen peroxide (H₂O₂) diffuses through the cell membrane and can be monitored in the extracellular space. Herein, we present a sensor for H₂O₂ detection released by cells in culture supernatants. H₂O₂ sensing performance was evaluated using chronoamperometric detection. A sensitivity of 0.0641 μA μM⁻¹ cm⁻² with a limit of detection of 6.55 μM and excellent selectivity against many interferents was found. H₂O₂ release was also measured in conditioned medium from human THP-1 macrophages exposed to pro-oxidant and anti-oxidant treatments. The results were compared with those obtained by flow cytometry using the same cells stained with carboxy-H₂DCFDA and MitoSOX Red, which detect intracellular ROS and mitochondrial superoxide, respectively. The addition of pro-oxidants lipopolysaccharide (LPS) and nigericin resulted in a significant increase in the cathodic current due to the H₂O₂ reduction, indicating an increased release of H₂O₂. The addition of 17-oxo-DHA, which inhibits LPS- and nigericin-dependent responses, decreased the LPS- and nigericin-induced release of H₂O₂. All the results obtained with the sensor were consistent with those obtained using flow cytometry. The operation of the sensor directly in the cell culture growth medium had no impact on cell viability. The sensor is highly sensitive, fast, and cost effective, and it can potentially be used for real time monitoring of oxidative stress.

氧化负荷增加导致大多数炎性疾病的发病机理，并与衰老和慢性炎症相关。巨噬细胞有助于在发炎的组织内产生活性氧（ROS）。当前，使用荧光探针和比色/荧光生化分析来测量ROS的产生。过氧化氢（H ₂ O ₂）扩散通过细胞膜，可以在细胞外空间进行监测。在这里，我们提出了一种传感器，用于检测培养上清液中的细胞释放的H ₂ O ₂。使用计时电流检测法评估H ₂ O _2的传感性能。灵敏度为0.0641μAμM ^-1  cm^-2的检出限为6.55μM，对多种干扰物具有极好的选择性。还从暴露于促氧化剂和抗氧化剂治疗的人类THP-1巨噬细胞的条件培养基中测量了H ₂ O _2的释放。将结果与使用羧基H ₂ DCFDA和MitoSOX Red染色的相同细胞通过流式细胞术获得的结果进行比较，后者分别检测细胞内ROS和线粒体超氧化物。由于H ₂ O _2的减少，添加了抗氧化剂脂多糖（LPS）和尼日利亚菌素导致阴极电流显着增加，表明H ₂ O _2的释放增加。17-氧代-DHA的添加，抑制LPS和尼日利亚的依赖反应，减少了LPS和尼日利亚的诱导H ₂ O _2的释放。使用传感器获得的所有结果与使用流式细胞仪获得的结果一致。传感器直接在细胞培养基中的操作对细胞活力没有影响。该传感器高度灵敏，快速且具有成本效益，可以潜在地用于实时监测氧化应激。