Atomic force microscopy study of cellulose surface interaction controlled by cellulose binding domains

Area of Science:

• Surface Science
• Biomaterials Engineering
• Colloid and Interface Science

Background:

• Cellulose surface interactions are crucial in biological and industrial applications.
• Cellulose binding domains (CBDs) are peptides that specifically bind to cellulose.
• Understanding CBDs' role in modifying cellulose interfacial properties is key.

Purpose of the Study:

• To investigate the interfacial interactions of model cellulose surfaces modified with CBDs.
• To elucidate the role of CBDs in altering the forces between cellulose surfaces.
• To examine the effect of CBD binding on surface topography and charge distribution.

Main Methods:

• Colloidal probe microscopy was employed to measure forces between surfaces.
• Atomic Force Microscopy (AFM) was used for surface imaging and topography analysis.
• Experiments were conducted in aqueous electrolyte solutions to study ionic strength effects.

Main Results:

• Pure cellulose interactions are dominated by double-layer repulsive forces, dependent on electrolyte concentration.
• CBD adsorption on cellulose surfaces leads to agglomeration and altered topography.
• Despite increased surface charge, modified surfaces showed less repulsive forces due to irregular protein distribution.
• Binding of double CBD hybrid proteins induced adhesion, unlike single CBDs.

Conclusions:

• CBDs significantly modify cellulose surface interactions, reducing repulsion and potentially introducing adhesion.
• Surface topography and non-uniform charge distribution of adsorbed CBDs are critical factors influencing interfacial forces.
• The valency of CBD binding (single vs. double) affects the adhesion properties of modified cellulose surfaces.