Shaping hydrogel bioinks into 3D, multiscale, perfusable models using multimodal printing

Area of Science:

• Biomaterials Engineering
• Biofabrication
• Tissue Engineering

Background:

• Fabricating complex 3D soft hydrogel structures is challenging due to trade-offs in print size, resolution, and bioink properties.
• Existing 3D printing methods have limitations in achieving multiscale and multi-material complexities simultaneously.

Purpose of the Study:

• To develop a hybrid 3D printing platform integrating additive and subtractive fabrication modes.
• To overcome challenges in multimodal fabrication for creating complex, perfusable hydrogel constructs.

Main Methods:

• Combined digital light projection (DLP) for macroscale additive fabrication with two-photon ablation (TPA) for microscale subtractive fabrication.
• Identified compatible hydrogel bioink formulations for both DLP and TPA processes.
• Resolved technical challenges including alignment, soft-hard material printing, and hydrogel swelling.

Main Results:

• Successfully fabricated centimeter-scale hydrogel constructs with embedded microscale perfusable topologies.
• Demonstrated fabrication of complex structures like perfusable microfluidic chips and dual-fluidic circuits mimicking the alveoli-capillary interface.
• Achieved multiscale complexities not possible with isolated DLP or TPA methods.

Conclusions:

• The hybrid DLP-TPA platform offers a novel solution for fabricating complex, multiscale, multi-material soft hydrogel structures.
• This technology can create advanced biofabrication constructs, including organ-on-chip models with in vivo-like complexity.
• The platform facilitates seamless media perfusion and improved handling of mechanically weak constructs.