Three-Dimensional Bioprinted MR-Trackable Regenerative Scaffold for Postimplantation Monitoring on T1-Weighted MRI

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Medical Imaging

Background:

• Three-dimensional (3D) bioprinted tissue scaffolds offer precise control for tissue regeneration.
• In vivo confirmation of scaffold placement and retention is critical postimplantation.
• Detecting unwanted implant migration is essential for therapeutic success.

Purpose of the Study:

• To integrate a safe, effective Magnetic Resonance (MR) contrast agent into a bioprinting workflow.
• To enable bright-contrast scaffold monitoring in vivo after implantation.
• To assess the feasibility of MR-guided scaffold tracking.

Main Methods:

• Bioprinted gelatin/alginate scaffolds were labeled with MnPNH2.
• In vitro and in vivo MRI (7.0 T) assessed scaffold T1 relaxation times.
• Cell viability and proliferation were evaluated over two weeks.
• Scaffold implantation in Sprague Dawley rats followed by longitudinal imaging.

Main Results:

• Cell viability remained high (>90%) after labeling and bioprinting.
• Labeled scaffolds showed significantly reduced T1 values in vitro and in vivo.
• In vivo imaging at 24 hours postimplantation and gross pathology confirmed scaffold migration beyond the imaging field.
• No significant differences in T1 values were observed between in vivo and in vitro labeled scaffolds.

Conclusions:

• An MR-detectable, cell-compatible bioprinted scaffold was successfully created.
• The T1-weighting contrast agent enabled high-resolution postimplantation scaffold tracking.
• Scaffold migration was observed, indicating a need for improved retention strategies.