Construction of an ultrasensitive non-enzymatic sensor to investigate the dynamic process of superoxide anion release from living cells

Publication date: 15 February 2018
Source:Biosensors and Bioelectronics, Volume 100
Author(s): Hongwei Wei, Tianyi Shang, Tiaodi Wu, Guoan Liu, Lan Ding, Xiuhui Liu
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^–13M (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.



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