Bioactivation Treatment with Mixed Acid and Heat on Titanium Implants Fabricated by Selective Laser Melting Enhances Preosteoblast Cell Differentiation.

Phuc Thi Minh Le,Hiroyuki Nakano,Hiroaki Takadama,Seine A Shintani,Hisashi Kitagaki,Takaaki Ueno,Morihiro Ito,Shuntaro Terauchi,Yoichiro Nakajima,Tomiharu Matsushita,Kazuya Inoue,Seiji Yamaguchi,Tatsuya Kakutani

doi:10.3390/nano11040987

Abstract

Selective laser melting (SLM) is a promising technology capable of producing individual characteristics with a high degree of surface roughness for implants. These surfaces can be modified so as to increase their osseointegration, bone generation and biocompatibility, features which are critical to their clinical success. In this study, we evaluated the effects on preosteoblast proliferation and differentiation of titanium metal (Ti) with a high degree of roughness (Ra = 5.4266 ± 1.282 µm) prepared by SLM (SLM-Ti) that was also subjected to surface bioactive treatment by mixed acid and heat (MAH). The results showed that the MAH treatment further increased the surface roughness, wettability and apatite formation capacity of SLM-Ti, features which are useful for cell attachment and bone bonding. Quantitative measurement of osteogenic-related gene expression by RT-PCR indicated that the MC3T3-E1 cells on the SLM-Ti MAH surface presented a stronger tendency towards osteogenic differentiation at the genetic level through significantly increased expression of Alp, Ocn, Runx2 and Opn. We conclude that bio-activated SLM-Ti enhanced preosteoblast differentiation. These findings suggest that the mixed acid and heat treatment on SLM-Ti is promising method for preparing the next generation of orthopedic and dental implants because of its apatite formation and cell differentiation capability.

Highlights

Titanium metal (Ti) and its alloys are widely used in the orthopedic and dental surgery fields because they possess a high corrosion resistance, good biocompatibility, and low elastic moduli closer to that of natural bone than other metals such as stainless steel and cobalt chromium alloy [1,2,3], but they do not bond directly to living bone and are difficult to shape [4,5]
We evaluated the effects of a high degree of surface roughness of the SLMTi materials with or without the mixed acid treatment of H2 SO4 and HCl and subsequent heat treatment on cellular behaviors such as cell morphology, cell viability, and osteogenic differentiation
1. surThe face of the cp-titanium metal (Ti) is seen to be flat in the magnified image while the surface of the Selective laser melting (SLM)-Ti disc surface of the cp-Ti is seen to be flat in the magnified image while the surface of the SLMexhibited a particular morphology due to the material-derived particles that were that partially

Summary

Introduction

Titanium metal (Ti) and its alloys are widely used in the orthopedic and dental surgery fields because they possess a high corrosion resistance, good biocompatibility, and low elastic moduli closer to that of natural bone than other metals such as stainless steel and cobalt chromium alloy [1,2,3], but they do not bond directly to living bone and are difficult to shape [4,5]. In the SLM technique, small Ti particles are melted and fused layer by layer using a high-intensity laser, and computer-aided design was applied to make three-dimensional structures of the materials [6,7]. SLM used to make materials with a high surface. Nanomaterials 2021, 11, 987 roughness and personalized to the needs of the bone defect(s) of each patient. SLM-Ti materials are commonly used in various research efforts in the medical and dental fields, to assess cellular behaviors in vitro [8,9] or osseointegration in vivo [10,11]. Implants fabricated by SLM are in clinical trials for patients with facial bone defects [12,13]

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Conclusion