Electrochemical Sensor for Carbonyl Groups in Oxidized Proteins

Area of Science:

• Biochemistry
• Analytical Chemistry
• Electrochemistry

Background:

• Protein oxidation by reactive oxygen species generates stable carbonyl groups, serving as biomarkers for oxidative stress.
• Quantifying protein carbonyls is crucial for understanding oxidative damage in biological systems.

Purpose of the Study:

• Develop an electrochemical sensor for detecting carbonyl groups in oxidized proteins.
• Utilize the redox properties of dinitrophenylhydrazine (DNPH) for carbonyl detection.
• Investigate the sensor's performance using bovine serum albumin (BSA) as a model protein.

Main Methods:

• Electrochemical detection of carbonyl groups using differential pulse voltammetry at a glassy carbon electrode.
• Immobilization of DNPH on a mixed 4-styrenesulfonic acid-nafion matrix to preserve redox properties.
• Characterization using Fourier-transformed infrared spectroscopy, scanning electron microscopy, and surface plasmon resonance.

Main Results:

• The hydrazine moiety of DNPH is electroactive and responsible for carbonyl complexation.
• Immobilized DNPH retained its redox properties.
• The oxidation peak of DNPH decreased with increasing incubation time and concentration of oxidized protein.
• Achieved sensor sensitivity of 0.015 nmol carbonyl per mg oxidized protein and detection limits of 50 μg oxidized BSA and 0.75 pmol carbonyls.

Conclusions:

• The developed electrochemical sensor effectively detects carbonyl groups in oxidized proteins.
• This sensor provides a sensitive method for quantifying protein oxidative stress.
• The sensor's performance was validated through various analytical techniques.