Bio-Medical Materials and Engineering - Volume 4, issue 5

Authors: Yahia, L'Hocine | Lombardi, Sylvie | Selmani, Amine | Drouin, Gilbert | Hlaouti, Mohamed

Article Type: Research Article

Abstract: The objective of this study was to determine the optimal experimental conditions for plasma treatment of polyester ligaments. Two different surface modification techniques were used: tetrafluoroethylene and methane. Gas flow rate, pressure, power, and treatment period giving a thin film with low friction coefficient and low surface energy was determined. Control and plasma treated surfaces were characterized by X-ray photoelectron spectroscopy to investigate the functionalization of the treated surfaces in detail. The surface tension of control and plasma treated surfaces were determined from contact angle measurements to understand the adhesion and reactivity of films with aqueous medium. The results …showed a decrease in friction coefficient from 0.45 to 0.28 and from 0.45 to 0.26 for thin films deposited respectively by tetrafiuoroethylene (TFE) and methane (CH4 ) plasma. Contact angles increased from 63° to 120° for TFE plasma and from 63° to 93°for CH4 plasma. Large contact angles mean a weak affinity between molecules in water/material phase, so that the power to attract cells to the surface of the material is too weak. The results showed that optimal film, i.e., low static friction coefficient and large contact angle, can be obtained by a CH4 plasma treatment at high power RF. For TFE plasma treatments, a low power RF is needed to obtain a thin film with a stable chemical structure. Show more

Keywords: polyester, synthetic ligaments, plasma treatment, friction

DOI: 10.3233/BME-1994-4501

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 5, pp. 347-356, 1994

Authors: Otsuka, Makoto | Matsuda, Yoshihisa | Hsu, Jer | Fox, Jeffery L. | Higuchi, William I.

Article Type: Research Article

Abstract: The effect of environmental conditions on the crystalline transformation of metastable calcium phosphates during grinding was investigated using X-ray diffractometry and fourier transformed infrared spectroscopy. A mixture of CaO and dicalcium phosphate anhydrate (DCPA, CaHPO4 ) did not transform after grinding in air. On the other hand, CaO and dicalcium phosphate dihydrate (DCPD, CaHPO4 2H2 O) were converted into a noncrystalline solid. Mixtures of DCPD and Ca(OH), transformed into low-crystallinity hydroxyapatite after grinding in air. When ground under N2 , a mixture of Ca(OH)2 and DCPD did not transform into hydroxyapatite, whereas that of DCPD: Ca(OH)2 :CaCO3 …= 1:0.8:0.2 did. The results of X-ray diffraction of FT-IR spectra suggested that the presence of carbon dioxide in the grinding system was necessary for transformation from metastable calcium phosphates to hydroxyapatite. Show more

Keywords: mechanochemical treatment, bioactive material, synthesis, environment during grinding, hydroxyapatite, phase transformation

DOI: 10.3233/BME-1994-4502

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 5, pp. 357-362, 1994

Authors: Lewis, Gladius

Article Type: Research Article

Abstract: The thrust of the present work is the demonstration of the feasibility of using an enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of a monoclonal antibody human serum. The antibodies used, 7E3 and D3GP3, have been proposed as platelet receptor blockers, being directed specifically against the platelet membrane receptors (glycoprotein IIb/IIIa) and thus of significance in the management of patients at a very high risk of thrombotic occlusion. It is shown that 7E3 is more easily adsorbed than D3GP3 and hence has a higher potential for the stated application.

Keywords: glycoprotein (GP) IIb/IIIa, monoclonal antibodies, enzyme-linked irnrnunosorbent assay (ELISA)

DOI: 10.3233/BME-1994-4503

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 5, pp. 363-367, 1994

Authors: Kim, Jeong K. | Park, Joon B.

Article Type: Research Article

Abstract: The longevity of the cemented total hip joint replacement depends on the integrity of the cement fixation with respect to the interfaces of the metal stem and bone, and stress/strain transmission and its distribution. A simple coil made of stainless steel wires was placed around a tapered stem in a simulated cement mantle to counteract the radial- and hoop-stress and static push-out mechanical tests were performed. The results show statistically significant increases in ultimate strain (+17.62%), ultimate load (+110.34%), stiffness (+117.63%), and fracture toughness (+153.63%) exhibited by the wire reinforcement over the control. Precoating with a thin layer of polymethylmethacrylate …may also enhance the mechanical properties of the reinforced cement mantle. This simple device may contribute to the longevity of the cement mantle by virtue of the enhanced mechanical properties, which in turn will be able to absorb more energy transmitted through the metal stem. Show more

Keywords: bone cement, fixation, wire coil reinforcement, mechanical properties, density

DOI: 10.3233/BME-1994-4504

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 5, pp. 369-380, 1994

Authors: Valenta, Jaroslav | Růžička, Milan | Čihák, Radomír

Article Type: Research Article

Abstract: The tissues are during their physiological function, e.g., in the course of growth, adolescence, and aging, subjected to a cyclic mechanical loading and to large displacements and rotations as well. A tissue free of all external tractions is in a state that minimizes its internal power. In the course of aging of the tissues, for instance in the wall of the aorta, the vein, and also in the myocardium or heart valves, the decrease of the water content and increase of the collagen content occurs; while in compact and trabecular bone the contents of both mineral substances and collagen, undergo …reduction. In accordance with it, the strain energy function and the constitutive equations of living tissue based on the hyperelasticity theory using rotationless strain were studied. On the base of the proposed eigenvalue decomposition of the rotationless strain tensor and hyperelasticity the strain energy function was formulated as depending on biological time of tissue. The quantity of strain energy function per unit of the biological time, which essentially characterizes the velocity of change of mechanical response of tissue in the course of its aging, was also defined. The coefficient of tissue aging is the further diagnostic parameter, which is independent of the rotationless strain tensor and expresses the relative change of mechanical response of tissue during the biological time. The corresponding constitutive equation of tissue depending on the biological time is also determined. On the base of the regression analysis the theoretical stress-strain curves for myocardium and blood vessels were determined. The numerical results reveal that the coefficient of aging progressively increases in hardening tissues (coronary artery, vena cava inferior) whereas at the softening tissues it has a relatively slow increase at the dependence on tissue aging. Show more

Keywords: hyperelasticity, rotationless strain, strain energy function, biological time, coefficient of aging

DOI: 10.3233/BME-1994-4505

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 5, pp. 381-395, 1994

Authors: Oshida, Y. | Hashem, A. | Nishihara, T. | Yapchulay, M. V.

Article Type: Research Article

Abstract: In addition to biological and mechanical compatibilities for promising implant materials, a morphological compatibility is proposed by the authors. It has been reported by many investigators that implant surface with appropriate roughness and pore size exhibit better bone ingrowth activities. However, these parameters cannot characterize the complexity of surface textures. In the present study, dentulous and edentulous mandibular alveolar bones were utilized. Four segments from each mandible were subjected to the Fractal Dimension (DF) analysis. It was found that the dentulous mandible showed the DF of 1.81 ± 0.03 while the edentulous mandible exhibitedDF of 1.55 ± 0.07, indicating that …the former has more complex surface texture. It was also found that there could be a linear relationship between the surface roughness and the fractal dimension. Show more

Keywords: morphological compatibility, surface texturing, implants, fractal dimension, mandibular bones

DOI: 10.3233/BME-1994-4506

Citation: Bio-Medical Materials and Engineering, vol. 4, no. 5, pp. 397-407, 1994