Silk fibroin-based inks for in situ 3D printing using a double crosslinking process

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• 3D Bioprinting

Background:

• The critical shortage of transplantable tissues and organs necessitates innovative solutions.
• In situ 3D bioprinting, printing directly within the patient, offers a promising approach.
• Current bio-inks require specific properties like rapid gelation, shape integrity, stability, and tissue adhesion.

Purpose of the Study:

• To develop and characterize silk fibroin-based bio-inks for in situ 3D bioprinting applications.
• To improve silk fibroin's suitability for in situ bioprinting by enhancing its gelation, stability, and adhesion properties.

Main Methods:

• Utilized a covalent crosslinking strategy involving pre-photo-crosslinking and in situ enzymatic crosslinking.
• Investigated two different silk fibroin molecular weights.
• Characterized the resulting hydrogels for mechanical properties, stability, degradation resistance, and in vitro tissue adhesion.

Main Results:

• The developed silk fibroin hydrogels exhibited rapid stabilization due to synergistic effects of covalent bonds and shear forces, promoting a shift towards beta-sheet structures.
• Hydrogels demonstrated good mechanical properties, long-term stability (over 14 days), and resistance to enzymatic degradation.
• Successful in vitro adhesion to surrounding tissues was confirmed.

Conclusions:

• Silk fibroin-based bio-inks with enhanced properties were successfully developed for in situ 3D bioprinting.
• The crosslinking strategy significantly improved hydrogel stability and mechanical integrity.
• These findings highlight the potential of modified silk fibroin for regenerative medicine and in situ tissue engineering applications.