Stretchable Oxygen-Tolerant Sensor Based on a Single-Atom Fe–N₄ Electrocatalyst for Observing the Role of Oxidative Stress in Hypertension

Abstract

Oxidative stress and related oxidative damage have a causal relation with the pathogenesis of hypertension. Therefore, it is crucial to determine the mechanism of oxidative stress in hypertension by applying mechanical forces on cells to simulate hypertension while monitoring the release of reactive oxygen species (ROS) from cells under an oxidative stress environment. However, cellular level research has rarely been explored because monitoring the ROS released by cells is still challenging owing to the interference of O 2 . In this study, an Fe single-atom-site catalyst anchored on N-doped carbon-based materials (Fe SASC/N−C) was synthesized, which exhibits excellent electrocatalytic activity for the reduction of hydrogen peroxide (H 2 O 2 ) at a peak potential of +0.1 V and can effectively avoid the interference of O 2 . Furthermore, we constructed a flexible and stretchable electrochemical sensor based on the Fe SASC/N−C catalyst to study the release of cellular H 2 O 2 under simulated hypoxic and hypertension conditions. Density functional theory calculations show that the highest transition state energy barrier from the oxygen reduction reaction (ORR), i.e., O 2 to H 2 O, is 0.38 eV. In comparison, the H 2 O 2 reduction reaction (HPRR) can be completed only by overcoming a lower energy barrier of 0.24 eV, endowing the HPRR to be more favorable on Fe SASC/N−C compared with the ORR. This study provided a reliable electrochemical platform for real-time investigation of H 2 O 2 -related underlying mechanisms of the hypertension process.

Temperature-Tunable Operando Nondestructive Detection of Electronic and Geometrical Structures in Battery Electrodes

“…As shown in the upper panel curves in Figure c, the spectra at different temperatures exhibit a red shift of the absorption edge (around 8340 eV) during discharging, indicating the decrease of the valence state for Ni 4+ . This is consistent with the reduction of a large fraction of Ni ions during the discharging process. , For the variations in local structural coordination, the Fourier transform of the EXAFS oscillations provides ample information like coordination number, bond distance, and so forth . As shown in the lower panel of Figure c, the amplitude of the first shell coordination drops evidently during discharging, demonstrating a decrease in the coordination number of oxygen atoms in the Ni–O octahedron.…”

“…22,23 For the variations in local structural coordination, the Fourier transform of the EXAFS oscillations provides ample information like coordination number, bond distance, and so forth. 24 As shown in the lower panel of Figure 2c, the amplitude of the first shell coordination drops evidently during discharging, demonstrating a decrease in the coordination number of oxygen atoms in the Ni−O octahedron. Meanwhile, it should also be noted that all in situ spectra for different operating temperatures have undergone a change with varying SOCs of pouch cells, but those variations are still too small to clearly show their structural changes in the electrochemical process.…”

Real-Time Quantification of Nanoplastics-Induced Oxidative Stress in Stretching Alveolar Cells

“…With fast response and excellent sensitivity, electrochemical sensing has been widely accepted for real-time monitoring of transient molecules released from cells, tissues, and living bodies. − Particularly, emerging stretchable electrochemical sensors equipped with excellent mechanical compliance offer a forceful tool for tracking biochemical response of deformed cells or tissues, − and they convincingly have distinct advantages as built-in flexible sensors for the evaluation of organ-on-a-chip systems. A preliminary work was the incorporation of flexible electrode into microfluidic vascular chip for real-time monitoring of NO signaling evoked by circumferential stretch .…”

Cu single-atom catalyst-based flexible hydrogen peroxide electrochemical sensor with oxygen resistance for monitoring ROS bursts

“…24 More recently, we found Fe single-atom-site catalyst exhibited excellent electrocatalytic activity for the reduction of hydrogen peroxide at a peak potential of 0.1 V and can effectively avoid the interference of O 2 . 25 These intensive studies have promoted the development of flexible hydrogen peroxide electrochemical sensor but further exploration is required for understanding ROS burst mechanism in a simulated physiological condition.…”