A Bone Glue with Sustained Adhesion under Wet Conditions.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Surgical Adhesives

Background:

• Bone glues commonly exhibit poor adhesion in wet environments, limiting their clinical utility.
• Photocurable poly(ethylene glycol) dimethacrylate matrices are a basis for bone adhesives.
• Improving wet adhesion is critical for effective bone tissue repair and fixation.

Purpose of the Study:

• To enhance the wet adhesiveness of a photocurable poly(ethylene glycol) dimethacrylate bone glue.
• To investigate the effect of in situ interpenetrating network formation using isocyanate functional star-shaped prepolymers.
• To evaluate the mechanical properties and bone adhesion of modified bone glues under wet conditions.

Main Methods:

• Formulation of bone glues with a poly(ethylene glycol) dimethacrylate matrix and biodegradable ceramic fillers.
• Addition of six-armed isocyanate functional star-shaped prepolymers (NCO-sP(EO-stat-PO)) to create interpenetrating networks.
• Assessment of 3-point bending strength, shear adhesion to cortical bone, and aging in phosphate-buffered saline (PBS).
• Microscopic and spectroscopic analysis (SEM, EDX) of fracture surfaces.

Main Results:

• The addition of NCO-sP(EO-stat-PO) did not significantly alter the 3-point bending strength (3.5-5.5 MPa).
• Wet storage in PBS reduced bending strength to ~1 MPa for all formulations.
• Adhesion to cortical bone increased from 0.15-0.2 MPa to 0.3-0.5 MPa with 20-40 wt% NCO-sP(EO-stat-PO).
• Modified glues retained shear strength (0.18-0.25 MPa) after 7 days in PBS, unlike unmodified glues.

Conclusions:

• In situ interpenetrating network formation with NCO-sP(EO-stat-PO) significantly improves the wet adhesion of bone glues.
• The modified bone glue demonstrates robust adhesion to cortical bone in simulated physiological conditions.
• This approach effectively addresses the challenge of poor wet adhesion in bone adhesives, enhancing their potential for surgical applications.