Comprehensive Characterisation of Photocurable PEGDA/Gelatine Hydrogels for Extrusion-Based 3D Printing.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Bioprinting

Background:

• Developing photocurable hydrogel inks is crucial for advanced biofabrication.
• Key requirements include optimal rheology, low cytotoxicity, and tunable mechanical properties.

Purpose of the Study:

• To formulate and characterize PEGDA-gelatine-collagen hydrogel inks using LAP photoinitiator.
• To evaluate the printability, mechanical properties, and biocompatibility of these inks.

Main Methods:

• Rheological characterization and flow modeling (Herschel-Bulkley).
• Mechanical stiffness modulation via light intensity.
• 3D printing using direct extrusion and FRESH methods.
• Quantification of residual photoinitiator (LAP) using NMR.
• In vitro cell viability and proliferation assays.

Main Results:

• The Herschel-Bulkley model accurately described ink flow behavior.
• Increasing light intensity enhanced hydrogel stiffness, allowing mechanical property control.
• Washing significantly reduced residual LAP, improving cell viability.
• The PeGeCol_10_2 formulation offered the best balance of properties.
• High-fidelity, large anatomical models were successfully printed.

Conclusions:

• The developed hydrogel inks, particularly PeGeCol_10_2, show significant potential for biofabrication.
• Washing is essential to remove cytotoxic photoinitiator residues.
• These inks are suitable for creating complex structures for soft-tissue prosthetics and tissue engineering.