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Block Polyelectrolyte Additives That Modulate the Viscoelasticity and Enhance the Printability of Gelatin Inks at
Tobias Göckler1,2, Fahed Albreiki1, Defu Li1
1Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States.
ACS Applied Polymer Materials
|March 14, 2024
Summary
Block polyelectrolytes (bPEs) improve the 3D printability of biopolymer inks by enhancing viscosity and enabling self-assembly. These bPE additives create stable, printable inks suitable for various applications.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Additive Manufacturing
Background:
- Extrusion-based 3D bioprinting often faces challenges with low viscosity and poor structural stability of biopolymer inks at physiological temperatures.
- Gelatin methacryloyl (GelMA) inks, while photocurable, exhibit limited printability due to insufficient viscosity at 37 °C.
Purpose of the Study:
- To investigate the utility of block polyelectrolyte (bPE) additives for enhancing the viscosity and 3D printability of extrusion-based biopolymer inks.
- To develop GelMA/bPE inks with improved rheological properties and structural integrity for 3D printing applications.
Main Methods:
- Addition of oppositely charged bPEs to photocurable GelMA solutions to induce complexation-driven self-assembly.
- Characterization of ink microstructure using small-angle X-ray scattering (SAXS).
- Rheological analysis to assess shear strength, shear thinning, yielding behavior, and recovery properties.
- Evaluation of 3D printing performance, including extrusion, shape fidelity, and post-extrusion stability.
Main Results:
- GelMA/bPE inks demonstrated significantly enhanced viscosity and printability at physiological temperatures compared to pure GelMA inks.
- Hierarchical microstructures (jammed micelles or 3D networks) formed by bPE self-assemblies were confirmed by SAXS, correlating with improved shear strength and printability.
- Tunable rheological properties, including prominent yielding and shear thinning, were achieved by varying bPE concentration.
- Photo-cross-linked GelMA/bPE hydrogels exhibited superior shear strength compared to GelMA hydrogels.
- Excellent printing performance was observed, with minimal swelling, good shape retention, and satisfactory shape fidelity.
Conclusions:
- Block polyelectrolytes are effective additives for enhancing the viscosity and 3D printability of extrusion-based biopolymer inks.
- The self-assembly of bPEs provides a mechanism for improving ink rheology and the mechanical properties of resulting hydrogels.
- This approach offers a practical strategy for developing bespoke extrusion inks with tunable properties for advanced 3D printing applications.
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