Engineered biofilm-based living hydrogel for bioprinting

Area of Science:

• Materials Science
• Biotechnology
• Synthetic Biology

Background:

• Functional living hydrogels integrate microbial biomass with polymeric matrices.
• This approach enables bottom-up and top-down design strategies for advanced materials.

Purpose of the Study:

• To design and characterize a two-part living hydrogel system.
• To incorporate genetically engineered Escherichia coli (E. coli) biofilms into a hydrogel matrix.
• To evaluate the material's suitability for bioprinting and its responsive properties.

Main Methods:

• Fabrication of a composite hydrogel matrix using polyvinylpyrrolidone (PVP), gelatin, and agar.
• Incorporation of genetically engineered E. coli biofilms expressing curli fibers.
• Assessment of physical, mechanical, and printing properties.
• Evaluation of cell viability, protein expression, and hydrogel responsiveness (water absorption, disintegration, fluorescence, pH).

Main Results:

• The living hydrogel exhibited viscoelastic, shear-thinning properties with a storage modulus suitable for extrusion bioprinting.
• The hydrogel demonstrated significant water absorption (5x dry weight) and rapid disintegration (50% in 8 hours).
• Incorporated E. coli maintained viability, expressed recombinant curli fusion proteins, and retained fluorescence and pH responsiveness after printing.

Conclusions:

• This study presents a versatile living hydrogel platform combining engineered biofilms with a polymer matrix.
• The material is suitable for bioprinting and retains biological functionality, offering potential for environmental sensing.
• This work provides a foundation for developing responsive, biologically active functional living materials.