4D bioprintable self-healing hydrogel with shape memory and cryopreserving properties

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Biofabrication

Background:

• Four-dimensional (4D) bioprinting integrates time with 3D bioprinting for advanced tissue implants.
• Self-healing and shape memory properties are crucial for novel applications like minimally invasive surgery devices.

Purpose of the Study:

• To develop a self-healing hydrogel with shape memory capabilities for 4D bioprinting.
• To evaluate the printability, mechanical properties, and cell compatibility of the developed hydrogel.

Main Methods:

• Fabrication of a self-healing hydrogel using biodegradable polyurethane (PU) nanoparticles and gelatin.
• Characterization of hydrogel properties including printability, UV-crosslinking, mechanical modulus, shape fixity, and recovery.
• Assessment of cell proliferation and differentiation of neural stem cells (NSCs) and mesenchymal stem cells within the bioprinted constructs.
• Evaluation of cryopreservation effects on cell viability and proliferation.

Main Results:

• The hydrogel exhibited excellent 3D printability, structural stability, and tunable modulus (1-60 kPa).
• The 4D printed constructs demonstrated high shape fixity (~95%) and recovery (~98%) with self-healing capabilities.
• The hydrogel supported continuous NSC proliferation and promoted cell differentiation through inter-cellular interactions.
• Cryopreserved hydrogels maintained cell proliferation similar to non-cryopreserved controls.

Conclusions:

• A novel 4D bioprintable, self-healable hydrogel with shape memory and cryopreservation properties was successfully developed.
• This material holds significant potential for customized biofabrication of tissue-engineered implants.
• The findings pave the way for advanced applications in regenerative medicine and minimally invasive surgical devices.