Bio-Medical Materials and Engineering - Volume 28, issue 1

Authors: Yamashita, Kimihiro | Okazaki, Masayuki

Article Type: Editorial

DOI: 10.3233/BME-171649

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 1, pp. 1-2, 2017

Authors: Okazaki, Masayuki

Article Type: Review Article

Abstract: The crystallographic properties of fluorapatite (FAp) and polytetrafluoroethylene (PTFE) as biomedical materials were compared. Both materials contain fluorine and casually belong to the hexagonal crystal system. It is interesting that FAp is an inorganic ionic crystal, while PTFE is an organic covalent-bond crystal. Generally, fluorine contributes to the physicochemical stability and in some cases to the biocompatibility. The crystal structure of FAp was initially analyzed in 1930 by Náray–Szabó, although the analysis of hydroxyapatite (HAp) was markedly delayed until 1964. The computer graphics display demonstrated that fluoride ions serve to stabilize the hydroxyapatite crystals and prevent dental caries. On the …other hand, PTFE crystal analysis was reported in 1954 by Bunn and Howells. The PTFE temperature-pressure phase diagram accepted for over 60 years is very complicated and insufficient. PTFE delicately changes its phase near room temperature, although at a glance it appears to have a simple form compared with DNA. Show more

Keywords: FAp, PTFE, hexagonal crystal, stability, phase diagram

DOI: 10.3233/BME-171650

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 1, pp. 3-8, 2017

Authors: Shen, Donghe | Horiuchi, Naohiro | Nozaki, Sosuke | Miyashin, Michiyo | Yamashita, Kimihiro | Nagai, Akiko

Article Type: Research Article

Abstract: Using a wet method, we have synthesized octacalcium phosphate carbonate, in which HPO4 2− in octacalcium phosphate is replaced with CO3 2− . The physical, crystal, and chemical properties of this new material were compared to octacalcium phosphate, Ca-deficient hydroxyapatite, and Ca-deficient carbonate apatite using X-ray diffraction, Fourier-transform infrared spectroscopy, inductively coupled plasma spectroscopy, and scanning electron microscopy. Surface roughness and morphology were also characterized, along with the ability to support proliferation and differentiation of MG63 cells, as measured by MTT and alkaline phosphatase assay. We found that octacalcium phosphate carbonate enhanced osteoblast proliferation more strongly than all other …materials tested. Similarly, Ca-deficient carbonate apatite, a hydrolysate of octacalcium phosphate carbonate, stimulated osteoblast differentiation to a better extent than Ca-deficient hydroxyapatite, a carbonate-free hydrolysate of octacalcium phosphate. These results indicate that octacalcium phosphate carbonate has good biocompatibility and osteoconduction, and incorporation of carbonate into octacalcium phosphate and apatite enhances bone regeneration. Show more

Keywords: Octacalcium phosphate, calcium-deficient hydroxyapatite, carbonate substitution, osteoblast, bone regeneration

DOI: 10.3233/BME-171651

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 1, pp. 9-21, 2017

Authors: Lee, Sungho | Ueda, Kyosuke | Narushima, Takayuki | Nakano, Takayoshi | Kasuga, Toshihiro

Article Type: Research Article

Abstract: Background: Niobia/magnesia-containing orthophosphate invert glasses were successfully prepared in our earlier work. Orthophosphate groups in the glasses were cross-linked by tetrahedral niobia (NbO4 ) and magnesia. Objective: The aim of this work is to prepare calcium orthophosphate invert glasses containing magnesia and niobia, incorporating silica, and to evaluate their structures and releasing behaviors. Method: The glasses were prepared by melt-quenching, and their structures and ion-releasing behaviors were evaluated. Results: 31 P solid-state nuclear magnetic resonance (NMR) and Raman spectroscopies showed the glasses consist of orthophosphate (PO4 ), orthosilicate (SiO4 ), and NbO4 tetrahedra. …NbO4 and MgO in the glasses act as network formers. By incorporating SiO2 into the glasses, the chemical durability of the glasses was slightly improved. The glasses reheated at 800°C formed the orthophosphate crystalline phases, such as β -Ca3 (PO4 )2 , Mg3 (PO4 )2 and Mg3 Ca3 (PO4 )4 in the glasses. The chemical durability of the crystallized glasses was slightly improved. Conclusions: Orthosilicate groups and NbO4 in the glasses coordinated with each other to form Si–O–Nb bonds. The chemical durability of the glasses was slightly improved by addition of SiO2 , since the field strength of Si is larger than that of Ca or Mg. Show more

Keywords: Biomaterials, phosphate invert glass, orthophosphate, magnesium, silicate, niobium

DOI: 10.3233/BME-171652

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 1, pp. 23-30, 2017

Authors: Maeda, Hirotaka | Tamura, Tomoyuki | Kasuga, Toshihiro

Article Type: Research Article

Abstract: Background: In our earlier work, tobermorite containing calcium phosphate (CP) clusters (CP-Tob) was hydrothermally prepared in the CaO–SiO2 –P2 O5 –H2 O system for biomedical applications. Objective: CP-Tob was used to investigate the influence of CP cluster incorporation on its biocompatibility. Methods: Tobermorite samples with and without CP clusters were hydrothermally prepared at 180°C for 40 h. The biocompatibility, structure, and density of states of the tobermorite samples were investigated by experimental and first principles methods. Results: The amounts of lysozyme and bovine serum albumin adsorbed on CP-Tob were higher than those on tobermorite …without CP clusters. Cluster incorporation caused a decrease in the solubility, resulting in the enhancement of the cell compatibility. The calculated results indicated that incorporating clusters, which interact with the silicate units of tobermorite, led to a change of the density of states of tobermorite. Conclusions: Incorporation of CP clusters in tobermorite led to improvement of the biocompatibility evaluated by biological and computational analyses. Show more

Keywords: Calcium silicate, calcium phosphate, biocompatibility, hydrothermal process, simulation

DOI: 10.3233/BME-171563

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 1, pp. 31-36, 2017

Authors: Yokogawa, Yoshiyuki | Yamauchi, Rie | Saito, Akira | Yamato, Yuta | Toma, Takeshi

Article Type: Research Article

Abstract: The adsorption capacity of mesoporous silicate (MPS) materials as an adsorbent for protein adsorption from the aqueous phase and the mechanism of the adsorption processes by comparative analyses of the applicability of five kinetic transfer models, pseudo-first-order model, pseudo-second-order model, Elovich kinetic model, Bangham’s equation model, and intraparticle diffusion model, were investigated. A mixture of tetraethyl orthosilicate (TEOS) and triblock copolymer as a template was stirred, hydrothermally treated to form the mesoporous SBA-15 structure, and heat-treated at 550°C to form the MPS material, SBA-15. The synthesized SBA-15 was immersed in a phosphate buffered saline (PBS) solution containing cytochrome c for …2, 48, and 120 hours at 4°C. The TEM observations of proteins on/in mesoporous SBA-15 revealed the protein behaviors. The holes of the MPS materials were observed to overlap those of the stained proteins for the first 2 hours of immersion. The stained proteins were observed between primary particles and partly inside the mesoporous channels in the MPS material when it had been immersed for 48 hours. For MPS when it had been immersed for 120 hours, stained proteins were observed in almost all meso-scale channels of MPS. The time profiles for adsorption of proteins can be described well by Bangham’s equation model and the intraparticle diffusion model. The Bangham’s equation model is based on the assumption that pore diffusion was the only rate controlling step during adsorption, whose contribution to the overall mechanism of cytochrome c adsorption on SBA-15 should not be neglected. The kinetic curves obtained from the experiment for cytochrome c adsorption on SBA-15 could show the three steps: the initial rapid increase of the adsorbed amount of cytochrome c , the second gradual increase, and the final equilibrium stage. These three adsorption steps can be interpreted well by the multi-linearity of the intraparticle diffusion model, proving the significant role of intraparticle diffusion as one of the rate controlling mechanisms. Show more

Keywords: Adsorption, cytochrome c, mesoporous silicate, kinetic modelling

DOI: 10.3233/BME-171654

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 1, pp. 37-46, 2017

Authors: Yamada, Shinya | Ota, Yoshio | Obata, Akiko | Kasuga, Toshihiro

Article Type: Research Article

Abstract: Background: Inorganic ions released from bioceramics and bioactive glasses have been reported to influence osteogenic cell functions. Cell responses depend on types of the ions provided, for example, silicate ion has been found to up-regulate their proliferation, differentiation and mineralization. Objective: Mouse osteoblast-like cells (MC3T3-E1) were cultured in media containing silicate and calcium ions with/without magnesium ion to evaluate their combined effects on the cell’s functions. Methods: The cells were cultured in the media containing the extract of silicate-containing vaterite (SiV) and magnesium- and siloxane-containing one (MgSiV) and normal medium and then their adhesion, proliferation, differentiation …and mineralization were evaluated. Results: The adhesion of the cells was enhanced when they were cultured in the medium containing MgSiV-extract. Their proliferation and differentiation were up-regulated in both media containing MgSiV-extract and SiV-extract. In particular, the MgSiV-extract significantly enhanced their differentiation than the SiV-extract. This was supported by the mineralization test’s results, which showed a large amount of mineral deposit was observed in the cells cultured in the MgSiV-extract medium. Conclusions: Providing the three kinds of ions was effective for up-regulating the cell’s mineralization compared to providing silicate and calcium ions without magnesium ion. Show more

Keywords: Osteoblast-like cells, mineralization, inorganic ions, calcium carbonate

DOI: 10.3233/BME-171655

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 1, pp. 47-56, 2017

Authors: Suzuki, Kitaru | Nagata, Kohei | Yokota, Tomohiro | Honda, Michiyo | Aizawa, Mamoru

Article Type: Research Article

Abstract: Background: There is a strong impetus for the development of alternative treatments for bone disease that avoid the complications associated with autografts and allografts. To address this, we previously developed porous apatite-fiber scaffolds (AFSs) which have three-dimensional interconnected pores, and constructed tissue-engineered bone by culturing rat bone marrow cells (RBMCs) using AFSs in a radial-flow bioreactor (RFB). Objective: To generate additional baseline data for the development of tissue-engineered bone constructed for clinical application using a RFB, we cultured RBMCs using AFSs under static conditions (hereafter, RBMC AFS culture), and monitored RBMC growth and differentiation characteristics in vitro , …and two weeks after subcutaneous inoculation into recipient rats. Methods: RBMCs were seeded to AFSs and growth, differentiation and calcification were monitored in vitro and in vivo by histological evaluation using hematoxylin eosin, alkaline phosphatase and alizarin red S stains. Results: RBMCs in/on AFSs proliferated and differentiated normally in vitro and in vivo , and calcification was evident two weeks after subcutaneous AFS culture implantation. Histological assays revealed that AFSs and RBMC AFS cultures were biocompatible, and did not induce inflammation or immunological rejection in vivo . Conclusions: These findings suggest that AFSs are a conducive microenvironment for bone regeneration and are well tolerated in vivo . The results provide valuable baseline data for the design of implant studies using tissue-engineered bone constructed by RFB. Show more

Keywords: Hydroxyapatite, apatite-fiber scaffold, rat bone marrow cells, histological evaluation, tissue-engineered bone

DOI: 10.3233/BME-171656

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 1, pp. 57-64, 2017

Authors: Kohata, Kazuhiro | Itoh, Soichiro | Horiuchi, Naohiro | Yoshioka, Taro | Yamashita, Kimihiro

Article Type: Research Article

Abstract: We characterized the electrical properties of living bone obtained from patients who had undergone total hip arthroplasty (THA) or hemiarthroplasty by means of analysis of the electrically polarized and nonpolarized bone specimens, and we discussed the role of an organic and inorganic matrix of human bone in bone piezoelectricity. We used human femoral neck bone that was harvested during THA for advanced osteoarthritis of the hip joint (OA group) and hemiarthroplasty for femoral neck fracture (FNF group). The specimens were scanned to evaluate the cancellous bone structures using micro-computed tomography, and we quantified the carbonic acid by attenuated total …reflection (ATR) spectra to estimate carbonate apatite. The stored electrical charge in the electrically polarized and nonpolarized bone specimens were calculated using thermally stimulated depolarized current (TSDC) measurements. Each TSDC curve in the groups had peaks at 100°C, 300°C and 500°C, which may be attributed to collagen, carbonate apatite and hydroxyapatite, respectively. It is suggested that organic substances are more effectively electrically polarized than apatite minerals by the polarization at room temperature and that the stored charge in living bone may be affected not only by total bone mass but also by bone quality, including 3-dimensional structure and structural component. Show more

Keywords: Electrical property, human bone, electrical polarization, osteoarthritis, osteoporosis, proximal femur

DOI: 10.3233/BME-171657

Citation: Bio-Medical Materials and Engineering, vol. 28, no. 1, pp. 65-74, 2017