Enzymatic Polymer Brush Interfaces for Electrochemical Sensing in Biofluids

Area of Science:

• Biomedical Engineering
• Electrochemistry
• Materials Science

Background:

• Electrochemical sensors require enzymes to detect non-electroactive small molecule biomarkers.
• Immobilizing enzymes with high activity and preventing sensor fouling in biofluids remain significant challenges.

Purpose of the Study:

• To develop a generic polymer brush strategy for robust enzymatic electrochemical sensor interfaces.
• To overcome limitations in enzyme immobilization, activity preservation, and biofluid compatibility.

Main Methods:

• Utilizing polymer brushes with generic conjugation chemistry for covalent enzyme immobilization (>1 μg/cm²).
• Characterizing the polymer brush interface for hydration, accessibility, and electrochemical properties.
• Testing sensor performance for glucose, glutamate, and acetylcholine detection in various conditions.

Main Results:

• Achieved high enzyme loading (>1 μg/cm²) with preserved activity on polymer brushes.
• Demonstrated minimal electrochemical impedance (<10 Ω) and free small molecule access.
• Successfully detected biomarkers glucose, glutamate, and acetylcholine, including cascade reactions.
• Maintained sensor functionality in diluted, unfiltered cerebrospinal fluid.

Conclusions:

• Polymer brushes offer a versatile platform for high-performance enzymatic electrochemical sensing.
• The developed interface overcomes key challenges in enzyme immobilization and biofluid compatibility.
• This strategy significantly expands the possibilities for enzymatic catalysis in electrochemical biosensors.