A visual electrochemiluminescence biosensor based on CuInZnS quantum dots for superoxide dismutase detection

Area of Science:

• Biochemistry
• Analytical Chemistry
• Materials Science

Background:

• Superoxide dismutase (SOD) is a vital antioxidant enzyme found in biological cells, crucial for neutralizing harmful superoxide free radicals.
• SOD plays a key role in the body's antioxidant defense system, working with other enzymes like peroxidase and catalase.
• Accurate and rapid detection of SOD is important for understanding oxidative stress and related biological processes.

Purpose of the Study:

• To develop a simple, fast, and visual electrochemiluminescence (ECL) sensor for the detection of superoxide dismutase (SOD).
• To utilize CuInZnS quantum dots (QDs) as an ECL luminophore for SOD quantification.
• To demonstrate the sensor's effectiveness in detecting SOD in biological samples like human blood.

Main Methods:

• Fabrication of a glassy carbon electrode (GCE) modified with CuInZnS quantum dots (QDs).
• Utilizing the competitive reaction between SOD and CuInZnS QDs for hydrogen peroxide, leading to ECL signal quenching.
• Visual detection of ECL signal changes using a smartphone camera for rapid SOD quantification.

Main Results:

• The proposed sensor achieved a low limit of detection (LOD) of 0.03 μg/mL for SOD.
• The ECL signal of CuInZnS QDs was effectively quenched by SOD in a concentration-dependent manner.
• The sensor demonstrated successful application in quantifying SOD in human blood samples, with visual confirmation via smartphone.

Conclusions:

• The developed CuInZnS QD-based ECL sensor offers a simple, rapid, and visual method for SOD detection.
• The sensor exhibits high sensitivity and potential for point-of-care applications in biological and clinical settings.
• This approach provides a promising platform for the development of novel biosensors for enzymatic activity monitoring.