Bio-Medical Materials and Engineering - Volume 13, issue 4

Authors: Aoki, Hideyuki | Tomita, Naohide | Morita, Yusuke | Hattori, Koji | Harada, Yasuji | Sonobe, Masato | Wakitani, Shigeyuki | Tamada, Yasushi

Article Type: Research Article

Abstract: Fibroin‐hydrogel sponge and collagen gel were used as scaffold for in vitro cartilage regeneration. Fibroin‐hydrogel sponge was formed by phase separation from freezed fibroin solution. Chondrocytes were harvested from proximal humerus, distal femur and proximal tibia of 4‐week‐old Japanese white rabbits and inoculated in the fibroin–hydrogel sponge and collagen gel. Those constructs were cultured in DMEM supplemented with 10% FCS and 50 ml L‐ascorbate at 37°C. Histological observation, measurement of sulfated glycosaminoglycan and cell density were carried out at 3, 7, and 14 days after the cultivation. Well‐defined cartilage tissue can be seen both in the fibroin–hydrogel sponge and …in the collagen gel. The matrix was intensely stained by safranin‐O and showed a metachromatic reaction in both group. However, the quantity of sulfated glycosaminoglycan and cell density of the fibroin–hydrogel sponge group were increased more rapidly than these of the collagen gel group. Thus, the chondrocytes proliferated in the fibroin sponge without losing their differentiated phenotype. It is possible that culture environment in the fibroin sponge was suitable for chondrocytes regeneration. Show more

Keywords: Cartilage regeneration, fibroin–hydrogel sponge, tissue engineering, chondrocytes

Citation: Bio-Medical Materials and Engineering, vol. 13, no. 4, pp. 309-316, 2003

Authors: Honl, Matthias | Rentzsch, Reemt | Schwieger, Karsten | Carrero, Volker | Dierk, Oliver | Dries, Sebastian | Louis, Hartmut | Pude, Frank | Bishop, Nick | Hille, Ekkehard | Morlock, Michael

Article Type: Research Article

Abstract: In revision surgeries of endoprostheses, the interface between implant and bone cement or bone must be loosened. Conventional tools have many disadvantages because of their size and limited range. Taking advantage of the selective and athermic cutting process, a plain water jet is already used in order to cut soft tissues. This study investigates the possibilities of both a plain and an abrasive water jet as cutting tools for revision surgery. Samples of the mid‐diaphysis of human femora and bone cement (CMW3) were cut with a plain water jet (PWJ) and an abrasive water jet (AWJ) at two different …jet‐to‐surface angles (30°,90°) and at five different pressure levels (30, 40, 50, 60, 70 MPa). For a PWJ a selective pressure range was identified, where only bone cement was cut. Injecting a bio‐compatible abrasive (lactose) to the jet stream resulted in significantly higher cut depths in both materials. Material removal in bone was significantly less at the smaller jet‐to‐surface angle for both techniques. No clear selectivity between bone and bone cement was observed for application of the AWJ. However, the material removal rate was significantly higher for bone cement than for bone at all pressure levels. The results indicate that an AWJ might be an alternative tool for cement removal. The possibility for localised cutting at interfaces could be an advantage for revision of a non‐cemented prosthesis. Show more

Keywords: Jet cutting, prosthesis, revision, bone cement, bone

Citation: Bio-Medical Materials and Engineering, vol. 13, no. 4, pp. 317-325, 2003

Authors: Bloss, Peter | Rothe, Wolfgang | Wünsche, Peter | Werner, Christian | Rothe, Alexander | Kneissl, Georg Dieter | Burger, Wolfram | Rehberg, Elisabeth

Article Type: Research Article

Abstract: The placement of angiographic catheters into the vascular system is a routine procedure in modern clinical business. The definition of objective but not yet available evaluation protocols based on measurable physical quantities correlated to the empirical clinical findings is of utmost importance for catheter manufacturers for in‐house product screening and optimization. In this context, we present an assessment of multiple mechanical and surface catheter properties such as static and kinetic friction, bending stiffness, microscopic surface topology, surface roughness, surface free energy and their interrelation. Theoretical framework, description of experimental methods and extensive data measured on several different catheters are provided …and in conclusion a testing procedure is defined. Although this procedure is based on the measurement of several physical quantities it can be easily implemented by commercial laboratories testing catheters as it is based on relatively low‐cost standard methods. Show more

Citation: Bio-Medical Materials and Engineering, vol. 13, no. 4, pp. 327-343, 2003

Authors: Morita, Yusuke | Tomita, Naohide | Aoki, Hideyuki | Wakitani, Shigeyuki | Tamada, Yasushi | Suguro, Toru | Ikeuchi, Ken

Article Type: Research Article

Abstract: The dynamic visco‐elastic properties of regenerated cartilage tissue were measured to evaluate its mechanical function during cultivation. Harvested chondrocytes from 4‐week‐old Japanese white rabbits were inoculated into fibroin sponge at a cell concentration of about 5×107 cells/ml. Dynamic visco‐elasticity measurements were performed under compressive loading to evaluate the load bearing function of the articular cartilage. The dynamic modulus and the dynamic loss of the regenerated cartilage increased and the peak value of tanδ, as well as the frequency at the peak, decreased with increasing cultivation time. The pores of the fibroin sponge became filled with newly formed tissue as …cultivation time increased. These changes in the visco‐elastic properties of the regenerated cartilage were compared with those of a model system, ethylene propylene diene monomer sponge with interstitial fluid, and appear to be a result of increased fluid flow resistance and internal loss. We conclude that the changes in the dynamic visco‐elastic properties of the regenerated cartilage were caused because of narrowing of the fluid path by synthesized extracellular matrix. Show more

Keywords: Regenerated cartilage, fibroin sponge, dynamic modulus, dynamic loss, loss tangent

Citation: Bio-Medical Materials and Engineering, vol. 13, no. 4, pp. 345-353, 2003

Authors: Ozeki, K. | Yuhta, T. | Aoki, H. | Asaoka, T. | Daisaku, T. | Fukui, Y.

Article Type: Research Article

Abstract: To evaluate the deterioration in the superelasticity of Ti‐coated NiTi orthodontic wires, titanium was coated onto wires to form a 1‐μm thick film using radio frequency magnetron sputtering. In superelasticity cycle tests, the σ5.0 value (the stress at 5.0% strain) of a Ti‐coated wire was lower than that of a non‐coated wire by 6.2% after one cycle, and by 10.4% after 20 cycles. In a three point bend tests, the L2.0 value (the load at 2.0 mm deflection) of a Ti‐coated wire was 2.55 N, and this was reduced by 39.0% of the L2.0 value of a …non‐coated wire (4.18 N). After the non‐coated and the Ti‐coated wires had been immersed in physiological saline for periods of four and eight weeks, the concentration of Ni ions released into each solution was detected using MIP‐Mass, and Ni peak intensity of the wires was measured using XPS. After eight weeks, the concentration of Ni ions released from the non‐coated and the Ti‐coated wires was 657 and 135 ppb, respectively. In a clinical test, no inflammation was observed during the entire attached period of four weeks in both the non‐coated and the Ti‐coated wire. In the Ti‐coated wire, little exfoliation of the Ti‐coating was observed using SEM and EDS. It was concluded that Ti‐coated NiTi orthodontic wire has much potential for its application, with a low probability of causing any Ni allergy. Show more

Keywords: NiTi orthodontic wire, superelasticity, sputtering, titanium, Ni allergy

Citation: Bio-Medical Materials and Engineering, vol. 13, no. 4, pp. 355-362, 2003

Authors: Li, Shuyu | Hu, Kuanghu | Su, Wanfang | Cai, Nian | Hu, Ming | Hu, Yingxiong

Article Type: Research Article

Abstract: Introducing the theory of fuzzy set, mathematical morphology and computerized mask fast scanning, we developed the TOOTH.SCA software and method to analyze the effect of fluoride (NaF) on ore content of human tooth enamel automatically and quantitatively. And we obtained some characteristic parameters, such as the depth, the type and the demineralized content of every scathing layer of dental caries. The smallest scale of mask scanning is 0.1 μm × 0.1 μm and the time required to analyze a sample is only 12 s. The applied software and method we built play an important role to the research on the …mechanism of pathological changes of teeth and preventing dental caries. Show more

Keywords: Human tooth enamel, mineral matter, fluoride, image information processing, mask scanning

Citation: Bio-Medical Materials and Engineering, vol. 13, no. 4, pp. 363-371, 2003

Authors: Wu, John Z. | Dong, Ren G. | Smutz, W. Paul | Schopper, Aaron W.

Article Type: Research Article

Abstract: In physiological loading conditions, the soft tissues in the hands and fingers are predominantly in compression. The goal of the present study was to characterize the nonlinear and time‐dependent behavior of skin in compression. The pigskin samples used in the study were collected from five different animals. The compression tests were performed in confined and unconfined loading configurations and at four different loading speeds (0.5, 1.0, 40, and 400 μm/s). A multi‐axial material model was proposed to simulate the nonlinear and viscoelastic behavior of the skin in compression. The good agreement between the model predictions and experimental data suggests that …the mechanical behavior of the skin in compression can be well characterized using the Ogden strain energy potential combined with a time‐integration using a Prony series. Our results show that the stress/strain curve of the skin is much stiffer in confined compression compared to that in unconfined compression, indicating that the compressibility of the skin is small. Show more

Citation: Bio-Medical Materials and Engineering, vol. 13, no. 4, pp. 373-385, 2003

Authors: Giri, Jyotsnendu | Ray, Amlan | Dasgupta, S. | Datta, D. | Bahadur, D.

Article Type: Research Article

Abstract: Superparamagnetic as well as fine ferrimagnetic particles such as Fe3 O4 , have been extensively used in magnetic field induced localized hyperthermia for the treatment of cancer. The magnetic materials with Curie temperature (Tc ) between 42 and 50°C, with sufficient biocompatibility are the best candidates for effective treatment such that during therapy it acts as in vivo temperature control switch and thus over heating could be avoided. Ultrafine particles of substituted ferrite Co1−a Zna Fe2 O4 and substituted yttrium–iron garnet Y3 Fe5−x Alx O12 have been prepared through microwave refluxing and citrate‐gel route respectively. Single‐phase compounds were …obtained with particle size below 100 nm. In order to make these magnetic nano particles biocompatible, we have attempted to coat these above said composition by alumina. The coating of alumina was done by hydrolysis method. The coating of hydrous aluminium oxide has been done over the magnetic particles by aging the preformed solid particles in the solution of aluminium sulfate and formamide at elevated temperatures. In vitro study is carried out to verify the innocuousness of coated materials towards cells. In vitro biocompatibility study has been carried out by cell culture method for a period of three days using human WBC cell lines. Study of cell counts and SEM images indicates the cells viability/growth. The in vitro experiments show that the coated materials are biocompatible. Show more

Keywords: Magnetic hyperthermia, nanomagnetic materials, YIG, Co–Zn ferrites

Citation: Bio-Medical Materials and Engineering, vol. 13, no. 4, pp. 387-399, 2003

Authors: Ignjatović, Nenad | Jovanović, Jelena | Suljovrujić, Edin | Uskoković, Dragan

Article Type: Research Article

Abstract: An injectable polydimethylsiloxane/hydroxyapatite (PDMS/HAp) composite cement was synthesised using linear PDMS and HAp (particles of about 100 nm in size) of different mass fractions. The effect of HAp mass fraction (5–60 mass%) on the hardness of PDMS/HAp composite cement was investigated. The hardness achieved is 25–49°ShA. Differential scanning calorimetry (DSC) was used to study the cross‐linking process and the influence of HAp on the temperature and duration of PDMS/HAp cross‐linking. The microstructure of composite cement surfaces after 10 days in vivo tests was observed by scanning electron microscopy (SEM). The presence of well‐adhered macrophages, fibroblasts and monocytes was found on …the implant surface upon its extraction from the organism. Show more

Keywords: Composite cement, polydimethylsiloxane/hydroxyapatite, hardness, cross‐linking, in vivo test

Citation: Bio-Medical Materials and Engineering, vol. 13, no. 4, pp. 401-410, 2003

Authors: Aoki, Hideyuki | Tomita, Nohide | Harada, Yasuji | Hattori, Koji | Sonobe, Masato | Suguro, Toru

Article Type: Research Article

Abstract: A new therapeutic system called the “total joint regeneration system” is proposed as a treatment for osteoarthritis and rheumatoid arthritis. We have developed devices which allow the regeneration of damaged cartilage under noninvasive mechanical stimulation. This paper introduces the basic concepts of total joint regeneration and reports the results of the first animal experiment using an internal‐fixator device using rabbits and a dog.

Keywords: Total joint regeneration, internal‐fixator device, cartilage

Citation: Bio-Medical Materials and Engineering, vol. 13, no. 4, pp. 411-417, 2003