A flexible and physically transient electrochemical sensor for real-time wireless nitric oxide monitoring

Rongfeng Li,Xu Zhang,Yongsheng Jie,Milin Zhang,Jinlong He,Congxi Huang,Yuping Deng,Jinzhu Jing,Lan Yin,Hui Qi,Xing Sheng,Laura Wheatley,Yuan Ma,Shengnan Liu

doi:10.1038/s41467-020-17008-8

Abstract

Real-time sensing of nitric oxide (NO) in physiological environments is critically important in monitoring neurotransmission, inflammatory responses, cardiovascular systems, etc. Conventional approaches for NO detection relying on indirect colorimetric measurement or built with rigid and permanent materials cannot provide continuous monitoring and/or require additional surgical retrieval of the implants, which comes with increased risks and hospital cost. Herein, we report a flexible, biologically degradable and wirelessly operated electrochemical sensor for real-time NO detection with a low detection limit (3.97 nmol), a wide sensing range (0.01–100 μM), and desirable anti-interference characteristics. The device successfully captures NO evolution in cultured cells and organs, with results comparable to those obtained from the standard Griess assay. Incorporated with a wireless circuit, the sensor platform achieves continuous sensing of NO levels in living mammals for several days. The work may provide essential diagnostic and therapeutic information for health assessment, treatment optimization and postsurgical monitoring.

Highlights

Real-time sensing of nitric oxide (NO) in physiological environments is critically important in monitoring neurotransmission, inflammatory responses, cardiovascular systems, etc
A schematic illustration of the transient NO sensor appears in Fig. 1a, and the corresponding fabrication procedure is given in Supplementary Fig. 1
Many reports suggest that gold nanoparticles are nontoxic with proper size and dosage, and metabolization occurs through kidney, bladder, or hepatobiliary systems[35,36,37], e.g., no significant side effects have been observed after 24 h with intravenous injection of gold nanoparticles (~100 μg)[38]

Summary

Introduction

Real-time sensing of nitric oxide (NO) in physiological environments is critically important in monitoring neurotransmission, inflammatory responses, cardiovascular systems, etc. Several techniques have been proposed to detect NO concentrations, including indirect methods such as Griess assays that measure the concentration of nitrite ion (NO2−) in solutions and direct methods such as fluorescent probes, electron spin resonance spectroscopy, and chemiluminescence[10,11,12,13]. Most of these techniques either suffer from insufficient detection limits or involve complicated sample preparation that impedes real-time measurements of NO in physiological environments[14,15]. Most reported encapsulation methods involve coating of materials on sensing electrodes that might not apply for devices that need direct exposure to chemicals of interest[25,28]

Methods

Results

Conclusion