Surfaces based on amino acid functionalized polyelectrolyte films towards active surfaces for enzyme immobilization

Area of Science:

• Materials Science
• Biochemistry
• Surface Chemistry

Background:

• Enzyme immobilization is crucial for biocatalysis and biosensor development.
• Tailoring surface properties is key to optimizing enzyme adsorption and activity.
• Polyelectrolytes offer versatile platforms for surface modification.

Purpose of the Study:

• To prepare and characterize polyelectrolyte films functionalized with amino acids on silicon wafers.
• To evaluate the effect of amino acid functionalization on enzyme adsorption and catalytic activity.
• To explore the potential of these surfaces for enzyme immobilization in biocatalysis.

Main Methods:

• Synthesis of poly(maleic anhydride-alt-vinylpyrrolidone) [poly(MA-alt-VP)] functionalized with glutamine, tyrosine, and methionine.
• Adsorption of functionalized polyelectrolytes onto amino-terminated silicon wafers under varying pH and ionic strength.
• Characterization using ellipsometry, contact angle measurements, and atomic force microscopy (AFM).
• Enzyme adsorption and activity assays using glucose 6-phosphate dehydrogenase (LmG6PD).

Main Results:

• Adsorption of polyelectrolytes varied with amino acid type, pH, and ionic strength, with glutamine showing highest adsorption at pH 3.5 and low ionic strength.
• Methionine-functionalized films exhibited the highest hydrophobicity.
• Enzyme adsorption and specific activity were influenced by the amino acid's side chain polarity, with methionine-functionalized surfaces yielding the best enzymatic performance for LmG6PD.

Conclusions:

• Amino acid functionalization of polyelectrolyte surfaces significantly impacts enzyme adsorption and activity.
• Methionine-functionalized poly(MA-alt-VP) surfaces provide an effective platform for immobilizing glucose 6-phosphate dehydrogenase.
• These functionalized surfaces represent a promising approach for developing enzyme immobilization strategies in biocatalysis.