S-layer-coated liposomes as a versatile system for entrapping and binding target molecules

Area of Science:

• Biotechnology
• Materials Science
• Nanotechnology

Background:

• Bacterial S-layer proteins offer a robust scaffold for functionalizing nanomaterials.
• Liposomes are versatile drug delivery vehicles, but controlled surface functionalization remains a challenge.

Purpose of the Study:

• To develop S-layer protein-coated liposomes for defined molecular binding using the streptavidin-biotin system.
• To identify membrane-impermeable reagents for S-layer crosslinking and functionalization without compromising liposome integrity.

Main Methods:

• Liposomes composed of dipalmitoyl phosphatidylcholine, cholesterol, and hexadecylamine were coated with Bacillus stearothermophilus S-layer protein.
• Hydrophilic dialdehyde and activated dicarboxylic acid were used for S-layer crosslinking.
• p-Diazobenzoyl biocytin was employed for biotinylation of the S-layer.
• Streptavidin and biotinylated anti-human IgG were immobilized to demonstrate functionalization.

Main Results:

• S-layer-coated liposomes (180 nm average size) were successfully prepared.
• Impermeable crosslinking reagents preserved S-layer structure and liposome integrity.
• Efficient biotinylation introduced accessible biotin residues per S-layer subunit.
• Ordered streptavidin layers and biologically active anti-human IgG confirmed successful surface functionalization.

Conclusions:

• S-layer protein-coated liposomes provide a stable and controllable platform for molecular immobilization.
• This method allows for the precise attachment of functional molecules via the streptavidin-biotin linkage.
• The developed system holds potential for applications in diagnostics, drug delivery, and biosensing.