Rapamycin/sodium hyaluronate binding on nano-hydroxyapatite coated titanium surface improves MC3T3-E1 osteogenesis

Abstract

Endosseous titanium (Ti) implant failure due to poor biocompatibility of implant surface remains a major problem for osseointegration. Improving the topography of Ti surface may enhance osseointegration, however, the mechanism remains unknown. To investigate the effect of modified Ti surface on osteogenesis, we loaded rapamycin (RA) onto nano-hydroxyapatite (HAp) coated Ti surface which was acid-etched, alkali-heated and HAp coated sequentially. Sodium hyaluronate (SH) was employed as an intermediate layer for the load of RA, and a steady release rate of RA was maintained. Cell vitality of MC3T3-E1 was assessed by MTT. Osteogenesis of MC3T3-E1 on this modified Ti surface was evaluated by alkaline phosphatase (ALP) activity, mineralization and related osteogenesis genes osteocalcin (OCN), osteopontin (OPN), Collagen-I and Runx2. The result revealed that RA/SH-loaded nano-HAp Ti surface was innocent for cell vitality and even more beneficial for cell osteogenesis in vitro. Furthermore, osteogenesis of MC3T3-E1 showed significant association with the mammalian target of rapamycin (mTOR) phosphorylation by RA, which required further study about the mechanism. The approach to this modified Ti surface presented in this paper has high research value for the development of Ti-based implant.

TCP/PLGA composite scaffold loaded rapamycin in situ enhances lumbar fusion by regulating osteoblast and osteoclast activity

“…It is worth noting that rapamycin can promote the expression of both osteoblasts related markers and osteoclasts related markers in vitro, which is consistent with previous studies (Barsh et al, 2015;Liu et al, 2017;Zhang et al, 2017). In combination with animal experiments, we suggest that although rapamycin can also promote the expression of TRAP in osteoclasts, mature osteoclasts mainly act on the stage of bone remodeling, resulting in the formation of denser bone (Koga et al, 2005;Kuroda et al, 2008;Wu et al, 2017).…”

mTORC2 regulates hierarchical micro/nano topography‐induced osteogenic differentiation via promoting cell adhesion and cytoskeletal polymerization

“… 27 In recent years, growing evidence has implicated that mTORC2 plays a critical role in bone homeostasis. 28 , 29 , 30 Rictor knock‐down in mature osteoblast and BMSCs resulted in impaired osteogenic differentiation in vitro and compromised bone formation in vivo. 31 , 32 In the process of osteoblast differentiation, mTORC2 was activated as the downstream of canonical Wnt signalling pathway.…”

A Review of In-Situ Grown Nanocomposite Coatings for Titanium Alloy Implants

“…Further details on the chemistry involved in the growth of HA would be discussed further in Section 3.4. The calculations from MTT assay by Liu et al is expressed in Figure 5A, whereby it could be observed that the cell growth during day 2 and 4 was not significantly different on PT, NT and HAp/NT [62]. But as from day 6, both NT and HAp/NT showed a higher number of cells.…”

“…To improve the adhesion and stability of HA coating on titanium (Ti), Liu et al [62] investigated the behaviour of osteoblast cells grown on HA-coated Ti. After having polished the titanium (PT), it was acid-etched (labelled ET) with the aim of roughening the surface.…”