Durable Zwitterionic Hydrogel Coating Reinforced with Chitosan Microspheres for Bone Fracture Fixation Devices.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Orthopedic Surgery

Background:

• Bone fixation implants often cause inflammation and thrombosis, risking patient health and treatment efficacy.
• Current implant materials require improved surface properties to mitigate adverse biological responses.

Purpose of the Study:

• To develop a novel zwitterionic hydrogel coating for polylactic acid (PLA) bone fixation devices.
• To enhance the mechanical strength, swelling resistance, and antifouling properties of implant surfaces.
• To evaluate the in vivo performance of the coated implants in promoting bone repair and reducing foreign body reactions.

Main Methods:

• Interfacial autocatalytic polymerization and in situ gelation were used to coat PLA devices with chitosan microsphere-enhanced poly(sulfobetaine) (CSM/PSBMA) hydrogel.
• The CSM/PSBMA hydrogel's mechanical strength, swelling resistance, and stability under various conditions (PBS immersion, shearing, ultrasonication, flushing) were assessed.
• The biocompatibility and bone healing acceleration of the coated PLA implants were evaluated in a rat femoral fracture model.

Main Results:

• The CSM/PSBMA hydrogel coating demonstrated superhydrophilicity and excellent antifouling properties.
• The coating exhibited remarkable stability, maintaining integrity after prolonged exposure to PBS, shearing, ultrasonication, and water flushing.
• CSM/PSBMA hydrogel-coated PLA implants significantly alleviated foreign body reactions and accelerated bone repair in vivo.

Conclusions:

• CSM/PSBMA zwitterionic hydrogel coatings offer a promising strategy for improving the performance of implantable medical devices.
• The developed coating enhances implant biocompatibility, stability, and bone regeneration capabilities.
• This approach presents a viable path for creating advanced coatings for orthopedic implants to improve patient outcomes.