Robotic Extrusion of Algae-Laden Hydrogels for Large-Scale Applications

Area of Science:

• Biomaterials Engineering
• Additive Manufacturing
• Microalgae Biotechnology

Background:

• Microalgae immobilization is crucial for various applications.
• Existing methods lack scalability and customization for architectural integration.
• Hydrogel-based bioprinting offers potential for large-scale, precise cell encapsulation.

Purpose of the Study:

• To develop a large-scale, custom bioprinting technique for microalgae immobilization.
• To characterize suitable hydrogel formulations for extrusion-based printing.
• To demonstrate the feasibility of integrating bioprinted microalgae into architectural elements.

Main Methods:

• Characterization of alginate-based hydrogels with rheology modifiers and varying water content (80-92.5%).
• Development of a custom multimaterial pneumatic extrusion system integrated with an industrial robot arm.
• Optimization of printing parameters (air pressure, viscosity, feed rate, speed, etc.) for layer-by-layer deposition.
• Post-curing of printed constructs using CaCl2 crosslinking and biocompatibility testing.

Main Results:

• Hydrogels with methylcellulose and carrageenan (80-92.5% water) exhibited suitable viscoelastic solid-like properties (G' > G″) for printing.
• A precision numerically controlled system achieved layer-by-layer deposition of viscous hydrogels.
• Microalgae cells demonstrated survival for 21 days within the printed hydrogel constructs.
• A 1000 × 500 mm fibrous hydrogel panel was successfully additively manufactured.

Conclusions:

• The developed bioprinting technique is effective for large-scale, custom microalgae immobilization.
• The characterized hydrogels and printing system support the integration of living microalgae into the built environment.
• This approach holds significant potential for novel architectural and bio-integrated design applications.