The detection of superoxide anions (O2•-) is widely considered as a potential way for cancer diagnosis and the development of enzyme-mimic catalysts is the main challenge in the establishment of electrochemical sensors for O2•- sensing in real samples. Here we present a novel enzyme- and metal-free electrochemical catalyst for superoxide (O2•-) sensing based on the widely-used carbon nanotubes (CNT). Through a one-step hydrothermal process induced by phytic acid (PA), CNT-based porous foam (PACNTF) was successfully obtained. Characterizations demonstrated the enhanced defect and disorder degree of PACNTF after PA treatment, which leaded to the increased active sites of PACNTF for electron transfer and the adhesion of O2•- during the electrochemical process. As a result, the PACNTF presented higher conductivity and larger current response toward O2•- sensing when compared with CNT precursor and CNTF without PA treatment. The sensitivity of PACNTF/SPCE was calculated to be 1230 μA cm-2 mM-1 in the linear range of 0-193.6 μM (R2 = 0.965) and 373 μA cm-2 mM-1 in the linear range of 193.6-1153.6 μM (R2 = 0.995) with a limit of detection of 0.16 μM (S/N = 3). Further, the PACNTF/SPCE presented fast response toward cell-released O2•- stimulated by Zymosan A. The above results indicated that the fabricated sensor holds potential usage in biological samples.

中文翻译：

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通过植酸诱导的一步水热过程制备用于超氧化物电化学传感的碳纳米管多孔泡沫

超氧阴离子 (O2•-) 的检测被广泛认为是癌症诊断的一种潜在方法，而酶模拟催化剂的开发是建立用于实际样品中 O2•- 传感的电化学传感器的主要挑战。在这里，我们提出了一种基于广泛使用的碳纳米管 (CNT) 的新型无酶和无金属电化学催化剂，用于超氧化物 (O2•-) 传感。通过植酸（PA）诱导的一步水热过程，成功获得了碳纳米管基多孔泡沫（PACNTF）。表征表明，PA处理后PACCNTF的缺陷和无序程度增强，导致电化学过程中PACNTF的电子转移活性位点增加和O2•-的粘附。因此，与未经过 PA 处理的 CNT 前体和 CNTF 相比，PACNTF 对 O2•-传感表现出更高的电导率和更大的电流响应。计算得出 PACNTF/SPCE 的灵敏度在 0-193.6 μM (R2 = 0.965) 的线性范围内为 1230 μA cm-2 mM-1，在 193.6-1153.6 μM 的线性范围内为 373 μA cm-2 mM-1 (R2 = 0.995) 检测限为 0.16 μM (S/N = 3)。此外，PACNTF/SPCE 对酵母多糖 A 刺激的细胞释放 O2•- 表现出快速响应。上述结果表明，所制造的传感器在生物样品中具有潜在用途。995)，检测限为 0.16 μM (S/N = 3)。此外，PACNTF/SPCE 对酵母多糖 A 刺激的细胞释放 O2•- 表现出快速响应。上述结果表明，所制造的传感器在生物样品中具有潜在用途。995)，检测限为 0.16 μM (S/N = 3)。此外，PACNTF/SPCE 对酵母多糖 A 刺激的细胞释放的 O2•- 表现出快速响应。上述结果表明制造的传感器在生物样品中具有潜在用途。