Development of functionalised polyelectrolyte capsules using filamentous Escherichia coli cells

Area of Science:

• Biomaterials Science
• Nanotechnology
• Microbiology

Background:

• Filamentous Escherichia coli (E. coli) cells, modified to express S-layer proteins, form natural bio-templates.
• These structures can be utilized for creating bio-inorganic composites and bio-inspired materials.
• Diverse biogenic materials offer potential for constructing advanced hybrid materials mirroring template form.

Purpose of the Study:

• To design and fabricate polyelectrolyte tubes using genetically modified filamentous E. coli as templates.
• To functionalize these tubes for potential applications as carriers for molecules or particles.
• To explore the creation of novel bio-inspired hybrid materials.

Main Methods:

• Genetically modified filamentous E. coli cells were fixed and coated with alternating layers of poly(sodium-4styrenesulfonate) (PSS) and poly(allylamine-hydrochloride) (PAH).
• E. coli cells were dissolved using sodium hypochlorite to yield hollow polyelectrolyte tubes.
• Tubes were functionalized with S-layer protein polymers and metallized with palladium (Pd(0)) particles.

Main Results:

• Hollow polyelectrolyte tubes with diameters of 0.7 μm and lengths of 5–50 μm were successfully fabricated.
• Analysis confirmed the structure and composition using light microscopy, SEM, EDX, and TEM.
• Functionalized tubes demonstrated potential for advanced material applications.

Conclusions:

• The developed polyelectrolyte tubes serve as novel bio-inspired materials.
• These materials offer possibilities for applications such as catalysts or metal nanowires for electrical devices.
• The novelty lies in using filamentous E. coli templates and S-layer proteins in this material construct.