Additively Manufactured and Surface Biofunctionalized Porous Nitinol

Area of Science:

• Biomaterials Engineering
• Orthopedic Surgery
• Materials Science

Background:

• Optimizing orthopedic biomaterials for bone regeneration and osseointegration is crucial.
• Additive manufacturing offers precise control over material architecture and properties.

Purpose of the Study:

• To create multifunctional porous nitinol with superelasticity, tailored microarchitecture, and biofunctionalized surfaces for enhanced bone tissue regeneration.
• To investigate the controlled release of biomolecules and their effect on cellular behavior.

Main Methods:

• Utilized selective laser melting (additive manufacturing) to fabricate porous nitinol structures based on triply periodic minimal surfaces.
• Biofunctionalized the nitinol surface with polydopamine-immobilized rhBMP2 to control release kinetics.
• Characterized material properties using microcomputed tomography, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy.
• Evaluated in vitro cellular response including attachment, proliferation, morphology, ALP activity, and calcium content.

Main Results:

• Achieved porous nitinol with microarchitectural properties closely matching design specifications.
• Confirmed the presence of polydopamine and rhBMP2 on the surface.
• Demonstrated adjustable, sustained release of rhBMP2 over 28 days.
• Observed significantly improved cell attachment, proliferation, morphology, ALP activity, and calcium content on biofunctionalized surfaces compared to as-manufactured samples.

Conclusions:

• The developed multifunctional porous nitinol exhibits superelasticity and a bone-mimicking architecture.
• The biofunctionalized surface enables controlled release of rhBMP2, promoting enhanced cellular response and bone regeneration.
• This material holds promise for advanced orthopedic implants designed for superior bone tissue regeneration and osseointegration.