ON-OFF ¹O₂ photoelectrochemical immunosensing strategy based on enzymatic conversion: interleukin-6 detection as...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Biosensing Technology

Background:

• Singlet oxygen (¹O₂)-mediated photoelectrochemistry (¹O₂-PEC) offers sensitive biomolecule detection with low background signals.
• Current ¹O₂-PEC methods face limitations due to photosensitizer modification requirements, restricting broad application.
• There is a need for adaptable and broadly compatible ¹O₂-PEC biosensing strategies.

Purpose of the Study:

• To develop a novel ON-OFF ¹O₂-PEC biosensing strategy utilizing alkaline phosphatase (ALP) as an enzymatic label.
• To demonstrate the flexibility and straightforward integration of this new strategy with standard immunoassay workflows.
• To establish ALP as a general and adaptable label for photoelectrochemical (PEC) immunoassays.

Main Methods:

• Employed ALP to catalyze the dephosphorylation of fluorescein diphosphate (FDP), converting an inactive precursor (OFF state) to an active photosensitizer (ON state).
• Developed an ON-OFF ¹O₂-PEC sensing mechanism based on enzymatic activation of the photosensitizer.
• Validated the strategy by detecting interleukin-6 (IL-6) as a model biomarker in diluted human serum samples.

Main Results:

• Achieved a limit of detection (LOD) of 85.4 pg/mL for IL-6 detection.
• Established a linear detection range for IL-6 from 100 to 500 pg/mL.
• Demonstrated adequate performance in complex biological matrices like diluted human serum.

Conclusions:

• The developed ALP-based ON-OFF ¹O₂-PEC strategy provides a flexible and adaptable platform for biosensing.
• This approach simplifies assay design and integrates seamlessly with existing immunoassay protocols.
• The strategy paves the way for developing compact, sensitive, and point-of-care diagnostic devices.