Different Cell and Tissue Behavior of Micro-/Nano-Tubes and Micro-/Nano-Nets Topographies on Selective Laser Melting Titanium to Enhance Osseointegration

Abstract

Background and Purpose: Micro-/nano-tubes (TNTs) and micro-/nano-nets (TNNs) are the common and sensible choice in the first step of combined modifications of titanium surface for further functionalization in the purpose of extended indications and therapeutic effect. It is important to recognize the respective biologic reactions of these two substrates for guiding a biologically based first-step selection. Materials and Methods: TNTs were produced by anodic oxidation and TNNs were formed by alkali-heat treatment. The original selective laser melting (SLM) titanium surface was set as control. Surface characterization was evaluated by scanning electron microscopy, surface roughness, and water contact angle measurements. Osteoclastogenesis and osteogenesis were measured. MC3T3-E1 cells and RAW 264.7 cells were used for in vitro assay in terms of adhesion, proliferation, and differentiation. In vivo assessments were taken on Beagle dogs with micro-CT and histological analysis. Results: TNN and TNT groups performed decreased roughness and increased hydrophilicity compared with SLM group. For biological detections, the highest ALP activity and osteogenesis-related genes expression were observed in TNT group followed by TNN group (P <0.05). Interestingly, when it comes to the osteoclastogenesis, TNNs displayed lowest TRAP activity and osteoclastogenesis-related genes expression and TNTs were lower than SLM but higher than TNNs (P <0.05). BV/TV around implants was highest in TNT group after 4 weeks (P <0.05). HE, ALP and TRAP staining showed that osteogenic and osteoclastic activity around TNTs were both higher than TNNs (P <0.05). Conclusion:TNNs and TNTs have dual advantages in promotion of osteogenesis and inhibition of osteoclastogenesis. Furthermore, TNNs showed better capability in inhibiting osteoclast activity while TNTs facilitated stronger osteogenesis. Our results implied that TNT substrates would take advantage in early application after implantation, while diseases with inappropriate osteoclast activity would prefer TNN substrates, which will guide a biologically based first-step selection on combined modification for different clinical purposes.

Molecular Response to Nanopatterned Implants in the Human Jaw Bone

“…, size, shape, and/or density) rather than the specific shape of the underlying microscale roughness, whether it is ordered or irregular. This assumption is at least partly supported by a recent study comparing two nanopatterns superimposed on microrough implants produced by selective laser melting . In that study, the ordered 70 nm nanotubular pattern, fabricated by anodic oxidization, resulted in less osteoclastic activity, in vitro and in vivo , higher bone formation activity, in vitro and in vivo , and higher BIC in vivo , compared to an irregular 100–120 nm nanotopography produced by alkali heat treatment on similar microrough implants .…”

“…This assumption is at least partly supported by a recent study comparing two nanopatterns superimposed on microrough implants produced by selective laser melting. 58 In that study, the ordered 70 nm nanotubular pattern, fabricated by anodic oxidization, resulted in less osteoclastic activity, in vitro and in vivo, higher bone formation activity, in vitro and in vivo, and higher BIC in vivo, compared to an irregular 100−120 nm nanotopography produced by alkali heat treatment on similar microrough implants. 58 Collectively, these findings from in vivo studies, even if limited in number at present, indicate an enhanced osseointegration in response to ordered nanopattern superimposed on a microroughness.…”

“…58 In that study, the ordered 70 nm nanotubular pattern, fabricated by anodic oxidization, resulted in less osteoclastic activity, in vitro and in vivo, higher bone formation activity, in vitro and in vivo, and higher BIC in vivo, compared to an irregular 100−120 nm nanotopography produced by alkali heat treatment on similar microrough implants. 58 Collectively, these findings from in vivo studies, even if limited in number at present, indicate an enhanced osseointegration in response to ordered nanopattern superimposed on a microroughness. These in vivo findings are further supported by several in vitro studies showing that such a combination of ordered nanopatterns and microroughness promote higher adhesion of MSCs and osteoblasts, osteoblastic differentiation, osteogenic activity, and mineral deposition.…”

Nanotopographical cues for regulation of macrophages and osteoclasts: emerging opportunities for osseointegration

“…In addition to the osteoid calcium phosphorus substrate, the topography of Ti significantly acts on the osteoclast differentiation. Several studies have been published on related topics, which reaches a consensus that the nanotopographies (nanotubes, nanonets, nanopillars, nanospikes) of Ti surfaces take inhibitory effect on osteoclast differentiation [ 154 , 160 , 161 ]. With regard to nanotubes, inhibitory effect increased with the diameter (Fig.…”

Surface Enhancement in Ti-6al-4v Fabricated by Selective Laser Melting on Bone-Like Apatite Formation

“…Among those, Tie6Al4V is widely utilized in additive manufacturing (AM) as a bioinert substance that can improve osseointegration and enhance the bone-implant contact in open reduction internal fixation (ORIF). Additive manufacturing, specifically selective laser melting (SLM), is a powder bed process that enables irregular and complex-shaped fabrication with high accuracy [2,3]. Therefore, it offers the potential to produce materials that are more precisely suited to anatomical fracture sites than commercially available implants [4].…”