Low-Potential Osmium-Based PVI redox polymer mediators for Diffusion-Controlled electrochemical glucose...

Area of Science:

• Electrochemistry
• Materials Science
• Biosensing

Background:

• Osmium-based redox polymer mediators are promising for low-potential electrochemical biosensing.
• Limited systematic evaluation of polymer-ligand coordination effects on electrode performance exists.
• Need for stable and selective glucose detection platforms.

Purpose of the Study:

• To synthesize and characterize an osmium-based polymer redox mediator, PVI-Os(dma-bpy)₂Cl.
• To evaluate its quantitative electrochemical performance for glucose detection.
• To investigate polymer-ligand coordination effects on electrochemical sensing.

Main Methods:

• Synthesis and characterization of PVI-Os(dma-bpy)₂Cl using UV-Vis, FTIR, ¹H-NMR, and zeta potential.
• Electrochemical characterization via cyclic voltammetry and multi-potential step (MPS) on carbon screen-printed electrodes.
• Immobilization of FAD-dependent glucose dehydrogenase (FAD-GDH) and optimization of measurement conditions (pH, enzyme loading).

Main Results:

• The synthesized polymer exhibited good aqueous dispersibility and strong positive surface charge.
• Efficient charge transport and diffusion-controlled redox behavior were observed.
• Optimized conditions yielded high sensitivity (7.4190 µA cm^-2 mM^-1) and linearity (R² = 0.99643) for glucose detection from 1-20 mM at 0.3 V.
• High selectivity against common electroactive interferents was demonstrated.

Conclusions:

• Ligand-tuned PVI-Os systems enable stable, low-potential, and interference-resistant electrochemical glucose detection.
• The developed mediator platform is suitable for integration into electrochemical glucose sensors.
• Potential applications in enzymatic biofuel cells.