Bio-Medical Materials and Engineering - Volume 20, issue 1

Authors: Soltysiak, Piotr | Höllwarth, Michael E. | Saxena, Amulya K.

Article Type: Research Article

Abstract: In order to construct tubes for tissue engineering of composite tubular organs in the gastrointestinal tract, suturing techniques were investigated with regards to (a) type of suture material, (b) state of scaffold, (c) technical variations and (d) changes in scaffold morphology. Collagen scaffolds of 13 mm diameter and 3 mm thickness, in both dry and wet states, were sutured using braided and monofilament sutures. Four suture techniques were employed (a) continuous loop, (b) interrupted loops, (c) interrupted edge sutures and (d) continuous running edge suture. Scanning electron microscopic imaging was performed on the 4 tubes sutured. Monofilament sutures were used …for tube formation as braided sutures were unsuitable. Dry scaffolds demonstrated tears during knot tying and fractures when bent around a stent. The interrupted and continuous running edge suture were the most suitable suturing techniques in wet scaffolds; further confirmed by scanning electron microscopy imaging. Our approach to tissue engineer segments of the gastrointestinal tract involves cell-seeding on scaffolds to permit attachment in vitro and later wrapping of scaffold layers of heterogeneous cells to create composite tissue. Scaffolds in wet state can be better sutured with monofilament materials using either the interrupted or running continuous edge suture technique. Show more

Keywords: Collagen, suturing techniques, tubes fabrication, tissue engineering, suture material

DOI: 10.3233/BME-2010-0610

Citation: Bio-Medical Materials and Engineering, vol. 20, no. 1, pp. 1-11, 2010

Authors: Sakurai, Miyuki | Abe, Hiroyuki | Okamura, Noboru | Inoue, Yohei | Akiyoshi, Takeshi | Matsuyama, Kenji | Uchida, Takahiro | Otsuka, Makoto

Article Type: Research Article

Abstract: Gabexate mesilate is a non-peptide protease inhibitor, developed in Japan, which is used in the treatment of acute pancreatitis and disseminated intravascular coagulation. This compound is readily hydrolyzed as it has ester bonds in its structure. It is now out of patent in Japan and there are many generic versions on the market. The crystal structure and the hydrolysate content of the branded product and nine generic versions were evaluated by X-ray diffractometry, thermal analysis and HPLC. The results showed that generic products containing mannitol as an additive had a higher content of hydrolysate as an impurity than the branded …product or generic products formulated without mannitol, suggesting that the crystal structure might be altered and stability impaired in mannitol-containing drug products. Show more

Keywords: Gabexate mesilate, mannitol, generic products

DOI: 10.3233/BME-2010-0611

Citation: Bio-Medical Materials and Engineering, vol. 20, no. 1, pp. 13-20, 2010

Authors: Ozeki, K. | Masuzawa, T. | Hirakuri, K.K.

Article Type: Research Article

Abstract: Diamond-like carbon (DLC) films were deposited on stainless steel (SUS), titanium (Ti) and nickel titanium (Ni–Ti) substrates using a radiofrequency plasma chemical vapour deposition method. Prior to DLC coating, the substrates were exposed to O2 and N2 plasma to enhance the adhesion strength of the DLC film to the substrate. After the plasma pre-treatment, the chemical composition and the wettability of the substrate surface was investigated by X-ray photoelectron spectroscopy (XPS) and water contact angle measurement, respectively. A pull-out test and a ball-on-disc test were carried out to evaluate the adhesion strength and the wear properties of the …DLC-coated substrates. The XPS results showed that the N2 and O2 plasma pre-treatment produced nitride and oxide on the substrate surfaces, such as TiO2 , TiO, Fe2 O3 , CrN and TiNO. In the pull-out test, the adhesion strengths of the DLC film to the SUS, Ti and Ni–Ti substrates were improved with the plasma pre-treatment. In the ball-on-disc test, the DLC coated SUS, Ti and Ni–Ti substrates without the plasma pre-treatment showed severe film failure following the test. The DLC coated SUS and Ni–Ti substrates with the N2 plasma pre-treatment showed good wear resistance, compared with that with the O2 plasma pre-treatment. Show more

Keywords: Diamond-like carbon, SUS, Ti, Ni–Ti, plasma CVD, plasma pre-treatment, adhesion, wear property

DOI: 10.3233/BME-2010-0612

Citation: Bio-Medical Materials and Engineering, vol. 20, no. 1, pp. 21-35, 2010

Authors: Amemiya, Takeshi | Nakamura, Takahiro | Yamamoto, Toshiro | Kinoshita, Shigeru | Kanamura, Narisato

Article Type: Research Article

Abstract: We immunohistochemically evaluated whether oral epithelial cells grown on amniotic membrane (AM) would be an effective biomaterial for reconstructing oral mucosal defects. Oral mucosal epithelial cells from albino rabbits were grown for 2–3 weeks on an AM carrier in a co-culture with 3T3 fibroblasts. The rabbits' oral mucosal defects were reconstructed by autologous transplantation of the oral epithelial sheets. The oral epithelial sheets and reconstructed tissues were then examined histologically and immunohistochemically. After 2–3 weeks of culture, the rabbit oral mucosal epithelial cells developed 5–7 layers of stratification on the AM. Immunohistochemistry revealed that they expressed keratins 4/13, integrin alpha …6, alpha 5 chain and collagen type III, but not keratins 1/10. The transplanted sheets attached to the mucosal defects, and AM fragments disappeared from the transplant area. Immunohistochemical patterns revealed properties of the mucous membrane and basement membrane components in the reconstructed epithelia. The results of this experiment showed that the AM-cultured oral epithelial sheets resulted in mucosa-like differentiation, and adhered to the mucosal defects. Therefore, AM-cultured oral epithelial sheets might be a useful biomaterial for oral mucosal reconstruction. Show more

Keywords: Oral epithelium, amniotic membrane, immunohistochemistry, tissue engineering, reconstruction

DOI: 10.3233/BME-2010-0613

Citation: Bio-Medical Materials and Engineering, vol. 20, no. 1, pp. 37-45, 2010

Authors: Asano, Takuji | Kinoshita, Yoshihiko | Kobayashi, Masaki | Nakao, Michiharu | Kanazawa, Hidetoshi | Hara, Yasuko | Furuse, Motomasa | Kuroiwa, Toshihiko

Article Type: Research Article

Abstract: The clinical treatments with blood purification therapy is most suitable in which a blood compatible adsorbent is employed. In the present study, two kinds of adsorber with different filling ratio (% rate with a bulk volume in the column volume (v)) with 83% (PAB-83) and 100% (PAB-100) were prepared, respectively. The adsorbent (PAB – Poly Arylate Beads), which was filled up in the column, was prepared with the phase-inversion method. Usually the major problems of blood purification therapy are blood clotting and the residual blood in the column during/after therapy process. The therapy should be interrupted when the internal pressure …of the column dramatically go up by such problems. We concluded that PAB does not affect the blood clotting formation in terms of endogenous clotting parameters, i.e., activated partial thromboplastin time (APTT), prothrombin time (PT) and the amount of fibrinogen (Fib). They lead to not dramatically decreasing of the essential protein. These adsorbers might be available to use as the adsorptive device for the blood purification therapy. Show more

Keywords: Blood compatibility, filling ratio, blood purification, adsorbent

DOI: 10.3233/BME-2010-0614

Citation: Bio-Medical Materials and Engineering, vol. 20, no. 1, pp. 47-54, 2010

Authors: Kachi, Naoyoshi D. | Otaka, Akihisa | Sim, Seungwoo | Kuwana, Yoshihiko | Tamada, Yasushi | Sunaga, Junko | Adachi, Taiji | Tomita, Naohide

Article Type: Research Article

Abstract: Condensation/aggregation process of rabbit-derived chondrocytes on a fibroin-coated patterned substrate was observed to estimate initial aggregation process in fibroin sponge. Chondrocytes were seeded on array of 160 μm diameter pits in three densities: 5 cells/pit (2.5×104 cells/cm2 , LOW), 15 cells/pit (7.5×104 cells/cm2 , MID) and 25 cells/pit (12.5×104 cells/cm2 , HIGH). In the MID and HIGH groups, cells tended to form aggregates after 24 h after cell seeding. In the LOW group, cell aggregate were not seen in a majority of the pits. Observation of aggregates using confocal laser scanning microscope showed that the chondrocytes at …the interface of the fibroin surface tended to extend to the surface, developing an extensive network of stress fibers throughout the cytoplasm. On the other hand, chondrocytes in the other part of the aggregates maintained spherical shape, and most of the actin was localized in the cell cortex as opposed to in stress fibers. These results suggest two functional structures in the aggregates, which may explain the good balance between the maintenance of their differentiated phenotype and proliferation rate in the fibroin sponge. Show more

Keywords: Chondrocyte, aggregate formation, fibroin sponge, cell migration

DOI: 10.3233/BME-2010-0615

Citation: Bio-Medical Materials and Engineering, vol. 20, no. 1, pp. 55-63, 2010