Effects of nacre-coated titanium surfaces on cell proliferation and osteocalcin expression in MG-63 osteoblast-like cells

Abstract

Titanium is widely used for dental implants because of its superior mechanical properties, low modulus, excellent corrosion resistance, and good biocompatibility. However, even when they are used in combination with a protective coating, such as hydroxyapatite (HA), titanium implants have been reported to have several disadvantages. These implants are unable to bond directly with the bone, and this impairs the anchorage of dental implants within the bone itself. In this study, a novel implant was obtained by implanting titanium implants into the epithelial mantle pearl sacs of a fresh water bivalve (Hyriopsis cumingii Lea), which has been used previously in a proof-of-concept study for the natural induction nacre coating. In vitro cell responses to the nacre-coated surface were evaluated by seeding MG-63 osteoblast-like cells onto the implant surfaces, and then assessing cell morphology, cell proliferation and markers of differentiation (alkaline phosphatase [ALP] activity and osteocalcin expression levels). Among all of the specimens tested, including multiple control surfaces, the nacre coatings had a stronger stimulatory on the MG-63 cells by altering cell morphology, and promoting proliferation and differentiation. These results indicate the bone-bonding capacities of nacreous coatings. However, further in vivo animal experiments are required to provide conclusive evidence for the bioactivity of nacreous coatings.

Key words: Dental implant, nacre, osteoblast, cell proliferation, osteogenesis.