Engineered, Robust Polyelectrolyte Multilayers by Precise Control of Surface Potential for Designer Protein, Cell,...

Area of Science:

• Materials Science
• Biomaterials Engineering
• Surface Chemistry

Background:

• Controlling surface interactions is crucial for biomedical applications.
• Layer-by-layer (LbL) assembly offers a versatile method for creating functional surfaces.
• Tuning surface charge is a primary strategy for managing biomolecule and cell adsorption.

Purpose of the Study:

• To fabricate robust, cross-linked LbL films with precisely controlled surface ζ-potential.
• To investigate the influence of surface charge on the adsorption of proteins, mammalian cells, and bacteria.
• To establish a model system for understanding electrostatic interactions in biological adhesion.

Main Methods:

• Fabrication of cross-linked LbL films using two weak polyions.
• Characterization of film properties (roughness, water affinity, surface charge at pH 7.4).
• Protein adsorption studies (BSA, LYZ) and atomic force microscopy (AFM) for adhesion force measurements.
• Mammalian cell (fibroblast) and bacteria adhesion tests.

Main Results:

• LbL films exhibited tunable surface charges (negative, zero, positive) while maintaining similar physical properties.
• Protein adsorption was dominated by electrostatic interactions, with higher binding of oppositely charged proteins.
• Non-specific adsorption of lysozyme (LYZ) was higher than bovine serum albumin (BSA) due to multilayer formation.
• Cell and bacteria adhesion strongly correlated with surface charge, showing high adhesion on positive surfaces and low adhesion on neutral/negative surfaces due to their inherent negative potential.

Conclusions:

• Cross-linked LbL assemblies provide a stable and tunable platform for controlling biomolecular and cellular interactions.
• Engineered surface charge is a critical factor in dictating the adhesion of proteins, cells, and bacteria.
• This approach has significant potential for developing advanced biomedical devices and materials.