In situ controllable heterojunction conversion strategy driven by oriented paper-based fluid transfer for human...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Sensitive detection of human immunoglobulin G (IgG) is crucial for disease diagnosis.
• Existing methods for IgG detection often suffer from low sensitivity, complex procedures, or high background interference.
• Development of novel biosensing platforms with enhanced performance is highly desirable.

Purpose of the Study:

• To develop a sensitive and selective electrochemical biosensor for human immunoglobulin G (IgG) detection.
• To utilize in situ heterojunction formation mediated by mercury ions (Hg²⁺) for signal amplification.
• To create a robust sensing platform with spatially separated dual working areas to minimize background noise.

Main Methods:

• Immobilization of antibody, silicon dioxide, and thymine-rich hairpin DNA onto antigen and antibody-modified electrodes.
• Formation of a sandwich-type structure enabling T-Hg²⁺-T complexation for Hg²⁺ capture.
• Conversion of zinc sulfide (ZnS) to zinc sulfide-mercuric sulfide nanocomposite via ion exchange triggered by Hg²⁺.
• Utilizing spatially separated working electrodes to enhance signal-to-noise ratio and selectivity.

Main Results:

• The developed sensor demonstrated high sensitivity for human IgG detection.
• The in situ heterojunction formation strategy significantly amplified the detection signal.
• The spatially separated working electrodes effectively reduced background interference, leading to high selectivity.
• The method showed potential for adaptation to other analytes and applications.

Conclusions:

• A novel electrochemical biosensing strategy based on mercury ion-mediated in situ heterojunction formation was successfully developed for sensitive human IgG detection.
• The unique design with spatially separated working areas and the ion exchange mechanism provides a low-background, highly selective, and robust sensing platform.
• This versatile protocol holds promise for applications in clinical diagnosis, environmental monitoring, and public safety by adapting the ion recognition probe.