Bio-Medical Materials and Engineering - Volume 17, issue 6

Authors: Li, Xiang | Huang, Jie | Ahmad, Zeeshan | Edirisinghe, Mohan

Article Type: Research Article

Abstract: Electrohydrodynamic spray deposition of a hydroxyapatite (HA) suspension consisting of nano-particles has been used to create a hydroxyapatite coating comprising of nanostructured surface topography. Preliminary coating experiments were carried out on an Al substrate and 30 s was found to be the most appropriate coating time. HA coating on titanium for this duration was found to be well-bonded to the substrate after heat-treatment. A thickness of 2 μm was achieved in 30 s and formation of a bone-like apatite on the surface was detected after incubation of the heat-treated coated Ti in simulated body fluid. Therefore, we have uncovered a …new procedure by which nano-biomaterials can be deposited on real orthopedic substrates to prepare bioactive thin coatings in a simple and easy manner. Show more

Keywords: Nano-hydroxyapatite, electrohydrodynamic, coating, titanium

Citation: Bio-Medical Materials and Engineering, vol. 17, no. 6, pp. 335-346, 2007

Authors: Meyer, Stephanie | Floerkemeier, Thilo | Windhagen, Henning

Article Type: Research Article

Abstract: The aim of this study was to evaluate histological and radiological osseointegration characteristics of implanted di-/tri-calciumphosphate in patients bone substitute material in opening-wedge osteotomies patients. Up to now the hypothesis of bioresorption and replacement with vital bone bases on numerous animal studies showing complete remodelling within 12–26 weeks. Histological patient studies hardly exist. In this study 13 patient biopsies were collected 16 months after tibial osteotomy. Unlike animal studies the results showed mainly incorporated avital cement residues (38%) as well as new bone formation (61%). Radiological scoring confirmed increasing signs of osseointegration and an incomplete resorption. In conclusion degradation and …replacement of di-/tri-calciumphosphate seems to be less accelerated in patients than prior animal studies indicated. Nevertheless, it shows excellent biocompatibility, good osteoconductive characteristics and may represents a useful alternative to autogenous graft. Show more

Keywords: Bone graft substitute, calciumphosphate, histology, remodelling, osseointegration

Citation: Bio-Medical Materials and Engineering, vol. 17, no. 6, pp. 347-356, 2007

Authors: Mueller-Rath, R. | Gavénis, K. | Gravius, S. | Andereya, S. | Mumme, T. | Schneider, U.

Article Type: Research Article

Abstract: The nude mouse model is an established method to cultivate and investigate tissue engineered cartilage analogues under in vivo conditions. One limitation of this common approach is the lack of appropriate surrounding articular tissues. Thus the bonding capacity of cartilage repair tissue cannot be evaluated. Widely applied surgical techniques in cartilage repair such as conventional and three-dimensional autologous chondrocyte implantation (ACI) based on a collagen gel matrix cannot be included into nude mouse studies, since their application require a contained defect. The aim of this study is to apply an organ culture defect model for the in vivo cultivation of …different cell-matrix-constructs. Cartilage defects were created on osteochondral specimens which had been harvested from 10 human knee joints during total knee replacement. Autologous chondrocytes were isolated from the cartilage samples and cultivated in monolayer until passage 2. On each osteochondral block defects were treated either by conventional ACI or a collagen gel seeded with autologous chondrocytes, including a defect left empty as a control. The samples were implanted into the subcutaneous pouches of nude mice and cultivated for six weeks. After retrieval, the specimens were examined histologically, immunohistochemically and by cell morphology quantification. In both, ACI and collagen gel based defect treatment, a repair tissue was formed, which filled the defect and bonded to the adjacent tissues. The repair tissue was immature with low production of collagen type II. In both groups redifferentiation of chondrocytes remained incomplete. Different appearances of interface zones between the repair tissue and the adjacent cartilage were found. The presented contained defect organ culture model offers the possibility to directly compare different types of clinically applied biologic cartilage repair techniques using human articular tissues in a nude mouse model. Show more

Keywords: Cartilage repair, organ culture model, autologous chondrocyte implantation, collagen gel, human articular chondrocyte

Citation: Bio-Medical Materials and Engineering, vol. 17, no. 6, pp. 357-366, 2007

Authors: Kuraishi, Keita | Ishida, Fujimaro | Kubo, Yoshichika | Niwa, Shigehiko | Mizuno, Masaki | Umeda, Yasuyuki | Waga, Shiro | Taki, Waro

Article Type: Research Article

Abstract: In an attempt to study bone remodeling by noninvasive methods, spinal bone radiodensity was assessed in five patients treated with anterior cervical decompression and fusion (ACDF) using cylindrical titanium cages. Plain radiographs were used to study specific areas of vertebral bone interposed in two-level cages with the two cephalad vertebrae for controls. Measurements were made immediately after surgery and 1, 3, 6, 12 and 18 months postoperatively. The data were analyzed quantitatively with a contrast-comparing method (CCM) using “Scion image”. There were two cyclical changes in vertebral remodeling. First, in all patients there were gradual increases in bone density at …the ventral part compared to the dorsal part of the vertebral body for up to 12 months; then the density decreased at 18 months. Second, a linear gradient in radiodensity from the ventral part to the dorsal part of the vertebral body observed immediately following spinal fusion gradually disappeared by 12 months; nonhomogeneous distributions of trabecular bone were appeared. Then, the linear gradient in density appeared again at 18 months. This investigation helps elucidate the radiographic evidence for the remodeling of vertebral bone in patients treated with ACDF. Show more

Keywords: Anterior cervical decompression and fusion, cylindrical titanium cages, radiography, contrast-comparing method, Scion image

Citation: Bio-Medical Materials and Engineering, vol. 17, no. 6, pp. 367-378, 2007

Authors: Guerin, S.R. | MacNiochaill, R. | O'Reilly, P. | O'Byrne, J. | Kelly, D.J.

Article Type: Research Article

Abstract: Hydrogen peroxide has been used for decades as an effervescent haemostatic agent in arthroplasty. Recently it has been shown to adversely affect the material properties of PMMA. We aim to assess whether any such deleterious effects are demonstrated in an experimental model which mimics the clinical use of hydrogen peroxide. Matched pairs of cancellous bone samples were treated with a swab soaked in either saline or a 3% solution of hydrogen peroxide, prior to manufacture of cement–bone constructs using Palacos or Simplex cement. Thirty pairs were then compared by subjecting them to a torsional shear force until failure and a …further thirty pairs were tested to failure in tension. There was no significant difference between the mean torques to failure for the Palacos-peroxide group versus the Palacos-saline group, or the Simplex-peroxide versus the Simplex-saline group (p=0.31 and 0.71 respectively). Similarly there was no significant difference between the mean tension loads to failure for the Palacos-peroxide group versus the Palacos-saline group, and the Simplex-peroxide versus the Simplex-saline group (p=0.79 and 0.23 respectively). We conclude that the use of hydrogen peroxide as an effervescent haemostatic agent has no detrimental effect on the mechanical integrity of the bone–cement interface when compared to normal saline. Show more

Keywords: Hydrogen peroxide, bone–cement interface, arthroplasty

Citation: Bio-Medical Materials and Engineering, vol. 17, no. 6, pp. 379-386, 2007

Authors: Zhou, Guo Shun | Su, Zhong Yuan | Cai, Yu Rong | Liu, Yu Kan | Dai, Li Cheng | Tang, Rui Kang | Zhang, Ming

Article Type: Research Article

Abstract: It is suggested that nanophase hydroxyapatite (nHAP) might have advantages over conventional hydroxyapatite (cHAP) as a biomaterial for bone regeneration. To be a satisfactory candidate for bone tissue engineering, it is important to support the growth and differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). The purpose of this study is to determine whether nHAP as cell growth substrata could give better support for attachment, proliferation and osteogenic differentiation of BMSCs than cHAP. Materials and Methods: nHAP and cHAP films were prepared as the substrata for the cell growth. BMSCs obtained from rabbit were seeded on the films. Attachment, proliferation …and osteogenic differentiation of BMSCs on the two kinds of films were evaluated. Results: Cell attachment ratio on nHAP films was significantly higher than that on cHAP films. Doubling time on nHAP films was significantly shorter than that on cHAP films. Amount of total proteins detected from cells cultured on nHAP films was significantly higher than that on cHAP films. However, alkaline phosphatase activity and osteocalcin content of the two groups showed no significant difference. Conclusions: nHAP films favored cell attachment and proliferation but not osteogenic differentiation of BMSCs compared with cHAP films. Show more

Keywords: Hydroxyapatite, nanophase, mesenchymal stem cells

Citation: Bio-Medical Materials and Engineering, vol. 17, no. 6, pp. 387-395, 2007

Article Type: Other

Citation: Bio-Medical Materials and Engineering, vol. 17, no. 6, pp. 397-402, 2007

Article Type: Other

Citation: Bio-Medical Materials and Engineering, vol. 17, no. 6, pp. 403-404, 2007