Injectable silk fibroin/polyurethane composite hydrogel for nucleus pulposus replacement

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Surgery

Background:

• Degenerative disc disease (DDD) is a common condition leading to intervertebral disc degeneration.
• Current treatments for DDD often involve invasive procedures with risks of complications like implant migration.
• There is a need for minimally invasive, effective treatments for DDD, such as nucleus pulposus replacement.

Purpose of the Study:

• To develop and characterize an injectable silk fibroin/polyurethane (SF/PU) composite hydrogel for nucleus pulposus replacement.
• To evaluate the mechanical, rheological, and biological properties of the SF/PU hydrogel for clinical applicability.
• To assess the imaging properties of the SF/PU hydrogel for surgical monitoring.

Main Methods:

• Preparation of SF/PU composite hydrogel via chemical cross-linking under physiological conditions.
• Mechanical testing (strength, height impact) and rheological property assessment.
• In vitro cell proliferation assay using bone marrow stromal cells.
• X-ray fluoroscopy, CT, and T2-weighted MRI for imaging evaluation.

Main Results:

• The SF/PU hydrogel demonstrated suitable mechanical strength and rheological properties for clinical use.
• The hydrogel was successfully injected through a small incision and supported bone marrow stromal cell viability and proliferation.
• The hydrogel exhibited excellent visibility in X-ray fluoroscopy, CT, and T2-weighted MRI, enabling real-time surgical monitoring.

Conclusions:

• The injectable SF/PU composite hydrogel is a promising candidate for nucleus pulposus replacement in DDD.
• Its favorable biomechanical properties, biocompatibility, and imaging characteristics support its potential clinical translation.
• This novel hydrogel offers advantages in terms of minimally invasive delivery and surgical guidance.