Bio-Medical Materials and Engineering - Volume 23, issue 3

Authors: Yoshida, Kaori | Sumita, Yoshinori | Marukawa, Eriko | Harashima, Masaru | Asahina, Izumi

Article Type: Research Article

Abstract: A robust method for inducing bone-formation without an autograft has not been established. Currently, both platelet-rich plasma (PRP) and bone morphogenetic protein (BMP) have been widely investigated for their clinical use in such cases. However, their synergistic effect is still controversial and previously shown diversity of this effect depends on various factors such as the bone substitutes involved. In this study, we investigated the synergistic effect of PRP and BMP2 on an alloplastic substitute as potentiators to induce in vivo bone-formation. A 10 mm diameter bony defect in rabbit calvarium was reconstructed using biphasic calcium phosphate (BCP) ceramics with or …without PRP, recombinant human (rh) BMP2, and their combination. At 6 and 12 weeks after implantation, rabbits were euthanized and the radiographic and histomorphometric features of bone reconstruction were analyzed. The results showed that defects filled by rhBMP2/BCP with or without PRP had high bone density at 6 and 12 weeks in radiological evaluation. However, in histomorphometric analysis, the defects filled by rhBMP2/BCP with PRP showed significant new bone formation compared with that by rhBMP2/BCP without PRP, especially at 6 weeks. We propose that the synergistic effect of PRP and rhBMP2 gives highly osteoinductive properties to alloplastic substitutes in vivo. Show more

Keywords: Bone regeneration, bone morphogenetic protein, platelet-rich plasma, alloplastic bone substitute

DOI: 10.3233/BME-130741

Citation: Bio-Medical Materials and Engineering, vol. 23, no. 3, pp. 163-172, 2013

Authors: Maeda, Eijiro | Noguchi, Hitoshi | Tohyama, Harukazu | Yasuda, Kazunori | Hayashi, Kozaburo

Article Type: Research Article

Abstract: The present study was performed to investigate effects of ageing on biomechanical properties of healing tissues of the patellar tendon (PT) after the removal of its central portion. An entire one-third defect was made in the PT of 0.5 year- (0.5 yr) and 2 year-old rabbits (2 yr). After 6 or 12 weeks, the tissue regenerated in the defect and the remaining, residual tissue was examined biomechanically and histologically. Age-related difference in the PT length was only observed in operated tendons at 6 weeks, and in the cross-sectional area such difference was observed only in unoperated, normal tendons. At 12 …weeks, tensile strength and tangent modulus of regenerated tissues in 0.5 yr were significantly higher than those in 2 yr. By contrast, these properties of residual tissues in 2 yr were significantly higher than those of 0.5 yr at 6 weeks. The histology of each of regenerated and residual tissues was essentially similar between the two age groups. Accordingly, ageing exhibited adverse effects on the mechanical properties of tissues regenerated in the central third defect of the PT. This may be due to high tangent modulus of normal and residual PT tissues in aged animals, which reduces the amount of mechanical stimulation applied to regenerated tissues during healing. Show more

Keywords: Patellar tendon, mechanical properties, ageing, regenerated tissue, residual tissue, regenerative medicine

DOI: 10.3233/BME-130742

Citation: Bio-Medical Materials and Engineering, vol. 23, no. 3, pp. 173-181, 2013

Authors: Fojt, Jaroslav | Joska, Ludek

Article Type: Research Article

Abstract: Porous materials allow for easier osseointegration of implants and their firmer connection with the bone. The presence of pores in a material may become a source of both mechanical and corrosion problems. The presented study explored a Ti-39Nb alloy with a porosity of 0–33%. Specimens were exposed in the physiological solution of two pH values. In view of this material's possible use in dental applications, the effect of fluoride ions on its corrosion behaviour was studied. The open circuit potential and polarization resistance were measured. Data concerning susceptibility to crevice corrosion were obtained from potentiostatic measurements based on the ASTM …F746 standard. In terms of corrosion behaviour, specimens with a lower porosity were not much different from the non-porous material. Porosity produced its effect at the level of 24 and 33%. It is obvious that porosity affects corrosion behaviour of this type of material. This conclusion was confirmed by measurements of susceptibility to crevice corrosion which grew with the specimens' increasing porosity. Corrosion resistance of the Ti-39Nb alloy was comparable with that of the compact material, but the presence of pores initiated a local attack of the material. Show more

Keywords: Titanium beta alloy, porosity, dental applications, fluoride ions, corrosion

DOI: 10.3233/BME-130743

Citation: Bio-Medical Materials and Engineering, vol. 23, no. 3, pp. 183-195, 2013

Authors: Mao, Keya | Zhou, Feihu | Cui, Fuzai | Li, Jiangtao | Hou, Xijun | Li, Peng | Du, Mingkui | Liang, Maohua | Wang, Yan

Article Type: Research Article

Abstract: Autogenous bone graft carries the risk of complications. In contrast, artificial bone graft provides initial strength and allows new bone ingrowth. In this study, we examined methods of preparation of α-calcium sulphate hemihydrate (α-CSH) and β-tricalcium phosphate (β-TCP), and a composite of the two materials. Characterization of the materials was determined with X-ray diffraction, differential thermal analysis (DTA), scanning electron microscopy (SEM), and porosity analysis. β-TCP exhibited the spatial structure and porosity of normal bone with a macropore size of 50–400 μm and some 1 μm micropores. α-CSH exhibited a regular crystal structure. A combined material was prepared in a …1:1 weight ratio, and in a rabbit model, the rate of new bone mineralization was similar to that of autogenous bone graft. The combined material of β-TCP and α-CSH in this study may provide similar efficacy as autogenous bone graft. Show more

Keywords: α-calcium sulphate hemihydrate, β-tricalcium phosphate, combined artificial bone, material synthesis, calcination

DOI: 10.3233/BME-130744

Citation: Bio-Medical Materials and Engineering, vol. 23, no. 3, pp. 197-210, 2013

Authors: Imani, Rana | Rafienia, Mohammad | Hojjati Emami, Shahriar

Article Type: Research Article

Abstract: In this study, preparation and characterization of soft crosslinked gelatin sponge for blood hemostasis application was considered. The effects of gelatin and crosslinker concentrations and altering freeze-drying temperature on sponges' density and structure, water absorption ability and biodegradation, cytotoxicity, mechanical properties and hemostatic effect were investigated. The density measurement indicated that the density of freeze-dried sponges increased when the freezing temperature was lowered. Scanning electron microscope and optical microscope images showed that gelatin sponges had uniform small pores (60 μm) after freezing at liquid nitrogen (−196°C). Biodegradation study demonstrated that the crosslinked sponges containing 1% and 2% gelatin lost respectively …nearly 40 to 70% of their weight during 24 h. Prepared sponges showed desired water absorption ability (30–40 times of own dry weight) improved by lowering glutaraldehyde concentration. Cell toxicity was not detected in any of the samples. Compression modulus of sponges decreased four times (160 to 40 kPa) as the gelatin content varied from 2 to 1% w/v. Hemostasis study confirmed that the hemolytic ability of sponges increased through raising gelatin content and porosity of sponge. We suggest using gelatin sponges containing 1% w/v gelatin, 0.5% w/v glutaraldehyde frozen in liquid nitrogen, as a potential substitution for local hemostat absorbable sponge. Show more

Keywords: Gelatin, glutaraldehyde, hemostat sponge, bioabsorbability

DOI: 10.3233/BME-130745

Citation: Bio-Medical Materials and Engineering, vol. 23, no. 3, pp. 211-224, 2013

Authors: Hohlrieder, M. | Teuschl, A.H. | Cicha, K. | van Griensven, M. | Redl, H. | Stampfl, J.

Article Type: Research Article

Abstract: Various studies have shown that physical stimuli modulate cell function and this has motivated the development of a bioreactor to engineer tissues in vitro by exposing them to mechanical loads. Here, we present a bioreactor for the physical stimulation of anterior cruciate ligament (ACL) grafts, whereby complex multi-dimensional strain can be applied to the matrices. Influences from environmental conditions to the behavior of different cells on our custom-made silk scaffold can be investigated since the design of the bioreactor allows controlling these parameters precisely. With the braided design of the presented silk scaffold we achieve maximum loads and stiffness values …matching those of the human ACL. Thus, the existent degummed and wet silk scaffolds absorb maximum loads of 2030±109 N with stiffness values of 336±40 N/mm. Show more

Keywords: Anterior cruciate ligament, bioreactor, silk, scaffold, mechanical properties

DOI: 10.3233/BME-130746

Citation: Bio-Medical Materials and Engineering, vol. 23, no. 3, pp. 225-237, 2013

Authors: Ozeki, K. | Hoshino, T. | Aoki, H. | Masuzawa, T.

Article Type: Research Article

Abstract: The adsorption behavior of albumin (BSA) and lysozyme (LSZ) on rod-shaped and plate-shaped hydroxyapatite (HA) was investigated to evaluate the influence of crystal orientation and morphology on the selective protein adsorption of HA. The rod-shaped HA was prepared by hydrothermal treatment from β-tricalcium phosphate (β-TCP) in H3 PO4 solution (pH 2.0 and 4.0 for HA-pH 2.0 and HA-pH 4.0). The plate-shaped HA was synthesized by hydrolysis of CaHPO4 –2H2 O (DCPD) in NaOH solution at 40°C and 80°C (HA-40°C and HA-80°C). The synthesized HA was characterized using scanning electron microscopy (SEM) and X-ray diffractometry (XRD). HA-pH 2.0 and HA-pH …4.0 produced rod-shaped crystals that were highly oriented to the a-face plane, whereas HA-40°C and HA-80°C showed a plate-like shape and a c-face preferred orientation. The peak intensity ratio I(300)/I(002) (a/c intensity ratio) from the XRD patterns increased in the following order: HA-80°C, HA-40°C, HA-pH 2.0 and HA-pH 4.0. It also increased as the Ca/P ratio decreased. The amount of adsorbed BSA increased in the following order: HA-pH 4.0, HA-pH 2.0, HA-40°C and HA-80°C. The amount of adsorbed LSZ on HA increased in the following order – HA-pH 2.0, HA-pH 4.0, HA-40°C and HA-80°C – with a corresponding decrease in the a/c intensity ratio. The BSA/LSA adsorption ratio increased with the a/c intensity ratio in the range of 3.3–8.9, and the BSA and LSZ were selectively adsorbed on HA, depending on the crystal shape. Show more

Keywords: Hydroxyapatite, adsorption, albumin, lysozyme, crystal orientation, morphology

DOI: 10.3233/BME-130747

Citation: Bio-Medical Materials and Engineering, vol. 23, no. 3, pp. 239-247, 2013