Faraday cage-type self-powered immunosensor based on hybrid enzymatic biofuel cell

Area of Science:

• Biosensors and Biofuel Cells
• Nanomaterials in Diagnostics
• Biomedical Engineering

Background:

• Enzymatic biofuel cell-based self-powered immunosensors (SPIs) suffer from low sensitivity and stability.
• High impedance and enzyme vulnerability limit current SPI performance.
• Need for enhanced sensing platforms for early disease detection.

Purpose of the Study:

• To develop a highly sensitive and stable self-powered immunosensor (SPI).
• To apply a Faraday cage-type sensing mode to a hybrid biofuel cell (HBFC)-based SPI.
• To demonstrate the potential of this novel platform for biomarker detection.

Main Methods:

• Utilized a hybrid biofuel cell (HBFC) with a Faraday cage-type sensing mode.
• Employed Au nanoparticle-reduced graphene oxide (Au-rGO) composite for bioanode construction and electron transfer.
• Immobilized detection antibody and glucose dehydrogenase (GDH) on the Au-rGO matrix.
• Used Cytokeratin 19 fragment (CYFRA 21-1) as the model analyte.
• Incorporated Fe-N-C as an inorganic cathode material for oxygen reduction reaction (ORR).

Main Results:

• The Faraday cage structure significantly reduced bioanode impedance by over 90% (from 4000 to 300 Ω).
• Achieved high sensitivity with an open circuit voltage (OCV) change of 68 mV [log (ng mL^-1)]^-1 for CYFRA 21-1.
• Demonstrated long-term stability of 4 weeks using the inorganic cathode.

Conclusions:

• The novel HBFC-based SPI with a Faraday cage design offers superior sensitivity and stability.
• This approach overcomes limitations of traditional EBFC-based immunosensors.
• Presents a promising sensing platform for self-powered, high-performance diagnostics.