Is surface chemical composition important for orthopaedic implant materials?

Area of Science:

• Biomaterials Science
• Cell Biology
• Surface Chemistry

Background:

• Ti-6Al-7Nb (NS) exhibits detrimental effects on fibroblast growth and colonization.
• Previous studies implicated NS topography, but the role of its surface chemistry was unclear.

Purpose of the Study:

• To investigate the specific contribution of Ti-6Al-7Nb (NS) surface chemistry to fibroblast behavior.
• To differentiate the effects of surface chemistry versus topography on cell response.

Main Methods:

• Model surfaces were created by evaporating gold or titanium onto standard NS, stainless steel (SS), and commercially pure titanium (TS).
• This approach standardized surface chemistry while maintaining characteristic topographies for comparison.
• Fibroblast growth, spreading, focal adhesion, and cytoskeletal organization were analyzed on coated and uncoated materials.

Main Results:

• Coated SS and TS supported cell proliferation, spreading, and mature focal adhesions, similar to their uncoated counterparts.
• Coated NS showed compromised proliferation, rounded cells, disrupted focal adhesions, and cytoskeletal networks, particularly near beta-phase particles.
• Cell behavior on coated NS mirrored that of uncoated NS, indicating topography as the primary factor.

Conclusions:

• The topography of Ti-6Al-7Nb (NS) is the primary determinant of stunted fibroblast growth, not its surface chemistry.
• Standardizing surface chemistry is a valuable method for comparing different biomaterials and surface finishes based solely on topography.