Bioengineering toughened, stretchable bacterial cellulose-based films inspired by spider silk

Area of Science:

• Biomaterials Science
• Materials Engineering
• Biotechnology

Background:

• Bacterial cellulose (BC) is a sustainable biomaterial with broad applications.
• BC's stiffness and low toughness limit its use in flexible materials like textiles.
• Spider silk is known for its exceptional toughness, combining strength and extensibility.

Purpose of the Study:

• To enhance the toughness and flexibility of bacterial cellulose.
• To develop a bioinspired strategy for toughening BC using a synthetic spider silk protein.
• To create advanced bio-based materials with improved mechanical properties.

Main Methods:

• Utilized E. coli JM109 (DE3) as a host for producing recombinant mini-spidroin (A3I)3-A14.
• Employed a glucose-gradient-driven method for in situ incorporation of the protein within the BC hydrogel network.
• Applied sodium dodecyl sulfate (SDS)-alkali treatment for controlled cell lysis and protein integration.

Main Results:

• Achieved deeper in situ incorporation of spider silk mini-spidroin within the BC matrix.
• BC-silk composites demonstrated over a 240% increase in toughness.
• The enhanced toughness was primarily due to a significant improvement in the strain at break, leading to lower stiffness and higher extensibility.

Conclusions:

• The developed bioinspired strategy effectively toughens bacterial cellulose using spider silk mini-spidroin.
• The resulting BC-silk composites exhibit a desirable balance of softness, strain tolerance, and energy absorption.
• These advanced bio-based materials show promise for applications requiring crease-resistant films, such as in textiles and wearable devices.