A visualization method for quickly detecting nitrite ions in breath condensate using a portable closed bipolar...

Area of Science:

• Electrochemistry
• Biosensing
• Nanomaterials

Background:

• Inflammation biomarkers in exhaled breath condensate (EBC) are crucial for diagnosing respiratory diseases.
• Current detection methods can be invasive or lack portability.
• Nitrite is a key biomarker associated with lung inflammation.

Purpose of the Study:

• To develop a portable, non-invasive electrochemical sensor for detecting nitrite in EBC.
• To integrate the sensor with a smartphone app for convenient analysis.
• To enable early detection of respiratory diseases through breath analysis.

Main Methods:

• Fabrication of a miniaturized bipolar electrochemical sensor using amine-functionalized graphene oxide (AGO) decorated with gold nanoparticles.
• Electrocatalytic oxidation of nitrite at the anodic pole and reduction of Prussian blue at the cathodic pole, leading to a color change.
• Smartphone-based colorimetric detection and validation using amperometry and voltammetry.

Main Results:

• The sensor demonstrated rapid electron transfer and high sensitivity for nitrite detection.
• Linear detection range up to 1230 μM with an ultralow limit of detection (LOD) of 250 nM.
• Successful differentiation of patients with respiratory diseases from healthy volunteers using real EBC samples.

Conclusions:

• The developed smartphone-connected sensor offers a portable and non-invasive method for measuring nitrite in EBC.
• This technology has the potential for early identification and monitoring of lung inflammation.
• The sensor's high sensitivity, selectivity, and ease of use make it suitable for clinical applications.