Simple 3,4-Dihydroxy-L-Phenylalanine Surface Modification Enhances Titanium Implant Osseointegration in Ovariectomized Rats

Abstract

Osteoporosis presents a challenge to the long-term success of osseointegration of endosseous implants. The bio-inspired 3,4-dihydroxy-L-phenylalanine (Dopa) coating is widely used as a basic layer to bind osteogenetic molecules that may improve osseointegration. To date, little attention has focused on application of Dopa alone or binding inhibitors of bone resorption in osteoporosis. Local use of a bisphosphonate such as zoledronic acid (ZA), an inhibitor of osteoclast-mediated bone resorption, has been proven to improve implant osseointegration. In this study, ovariectomized rats were divided into four groups and implanted with implants with different surface modifications: sandblasted and acidetched (SLA), SLA modified with Dopa (SLA-Dopa), SLA modified with ZA (SLA-ZA), and SLA modified with Dopa and ZA (SLA-Dopa + ZA). Measurement of removal torque, micro-computed tomography and histology revealed a greater extent of bone formation around the three surface-modified implants than SLA-controls. No synergistic effect was observed for combined Dopa + ZA coating. Microarray analysis showed the Dopa coating inhibited expression of genes associated with osteoclast differentiation, similarly to the mechanism of action of ZA. Simple Dopa modification resulted in a similar improvement in osseointegration compared to ZA. Thus, our data suggest simple Dopa coating is promising strategy to promote osseointegration of implants in patients with osteoporosis.

Quercitrin Nanocoated Implant Surfaces Reduce Osteoclast Activity In Vitro and In Vivo

“…For instance, hydrophilic SLA active surfaces, which are used in clinics with proven success [ 28 , 29 ], have been reported to affect osteoclastogenesis [ 30 , 31 ], decreasing osteoclast differentiation and activity in vitro. Recently, bioinspired dopamine coatings on Ti surfaces had also shown to inhibit the expression of genes related to osteoclast differentiation [ 32 ]. A main contribution to dental implant success is related to stability.…”

Implant‐bone‐interface: Reviewing the impact of titanium surface modifications on osteogenic processes in vitro and in vivo

“…Dopamine coating facilitated bone formation by inhibiting the expression of genes associated with osteoclast differentiation. 105 Similarly, titanium implant surface coating with antimicrobial agents, such as the bactericidal cationic peptide GL13K, not only inhibited microbial activity but also promoted osteointegration after 6 weeks of implantation in a rabbit femur model. 106 The addition of silicon‐substituted nano‐HAp to the surface of a selective laser structured titanium implant, inserted into the rabbit femur, promoted more organized bone formation, especially at the later stages of bone healing compared to implants without additional chemical treatment.…”

Image‐based design and 3D‐metal printing of a rat hip implant for use in a clinically representative model of joint replacement

“…In the future, it may be beneficial to create heads that can be fit modularly with implant stems, to achieve an optimal implant fit in both the acetabulum and the proximal femur in each animal. This would also allow for combinations of metal allows to be used, such as a cobalt‐chrome head that is preferred for studying an articulating joint surface at the metal‐on‐cartilage interface, 10,11 and a modifiable titanium stem that is preferred for osseointegration studies 1‐5 . Engineering an appropriately scaled and consistent taper joint between the head and neck of a rat‐sized implant would likely be difficult to achieve, but could be investigated as well.…”

“…The development of clinically representative animal models is critical for advancing translational orthopaedic research into areas related to joint replacement, such as osseointegration, [1][2][3][4][5][6][7][8] metal-on-cartilage wear, [9][10][11] and peri-prosthetic joint infection (PJI). [12][13][14][15][16] Preclinical studies that evaluate changes around a functional implant have been limited to large-animal 9,10,17 and companion-animal models, [18][19][20] which can accommodate commercially available joint-replacement components that mimic or replicate human implants.…”

“…Generation 2 rat-specific 3D-printed implants. Five sizes(1)(2)(3)(4)(5) were created to accommodate a range of skeletally mature rats (male, Sprague-Dawley, 390-605 g). Implants shown were 3D-printed in Ti6Al4V titanium with heads polished to a mirror-like finish with a dental tool and progressively finer grits of polishing stones and rubber wheels[Color figure can be viewed at wileyonlinelibrary.com] T A B L E 2 Baseline and postoperative weights for animals following hip hemiarthroplasty I G U R E 9 Intraoperative view of a Generation 1 custom rat hip monoblock implant in situ.…”