Bio-Medical Materials and Engineering - Volume 19, issue 2-3
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The aim of
Bio-Medical Materials and Engineering is to promote the welfare of humans and to help them keep healthy. This international journal is an interdisciplinary journal that publishes original research papers, review articles and brief notes on materials and engineering for biological and medical systems.
Articles in this peer-reviewed journal cover a wide range of topics, including, but not limited to: Engineering as applied to improving diagnosis, therapy, and prevention of disease and injury, and better substitutes for damaged or disabled human organs; Studies of biomaterial interactions with the human body, bio-compatibility, interfacial and interaction problems; Biomechanical behavior under biological and/or medical conditions; Mechanical and biological properties of membrane biomaterials; Cellular and tissue engineering, physiological, biophysical, biochemical bioengineering aspects; Implant failure fields and degradation of implants. Biomimetics engineering and materials including system analysis as supporter for aged people and as rehabilitation; Bioengineering and materials technology as applied to the decontamination against environmental problems; Biosensors, bioreactors, bioprocess instrumentation and control system; Application to food engineering; Standardization problems on biomaterials and related products; Assessment of reliability and safety of biomedical materials and man-machine systems; and Product liability of biomaterials and related products.
Abstract: Samples of Paramecium caudatum are observed by means of a scanning electron microscope (SEM) and a projection X-ray microscope (XRM) with computer tomography (CT) function. The samples are fixed with two kinds of fixatives, glutaraldehyde and osmium-tetra oxide acid. After the fixation and replacement procedure with t-buthyl alcohol, the samples followed by a freeze drying, well retain their structures. Surface structures, cilia and microfibrillar systems including infraciliary lattice structures, are clearly depicted by SEM observation. On the other hand, XRM images give quite different information, namely, in the case of osmium oxide fixation, the structures of internal organelles like the…macronucleus placed in the central part of cell body and trichocysts located under the cell membrane of a whole body are visible. In the case of glutaraldehyde fixation, the surface structures and internal structures are both visible but their image contrast is fairly weak. In order to examine toxicological effect, Paramecium caudatum samples treated in the environmental condition containing nano-particles of Ag (17 nm across) and Co-ferrite (300 nm across) are observed with results of certain morphological differences, namely, inner vacuoles increase in number and in volume in Co-ferrite treated cells as compared with Ag treated ones. But then, cilia-less areas increase on the surface of the body of Ag treated cells. In the case of Co-ferrite treated cells, cilia-less areas are not clearly detected. Whether these morphological differences observed in Ag and Co-ferrite treated cells are caused by the differences of materials or particle sizes remain to be examined in future.
Abstract: In the present study, we focused on the optimal conditions for observation of morphology and atomic structure of carbon nanotube (CNT) in vivo by transmission electron microscopy (TEM). Either low-voltage or high-voltage TEMs was chosen for the high-contrast or high-resolution imaging of subcutaneous tissue and the multi-wall CNT (MWCNT). The morphology and structure of each cell organelle were well recognized using the low-voltage TEM at 75 kV. Individual MWCNTs forming the cluster were also visible by the low-voltage TEM. On the contrary, the high-voltage TEM image at 1250 kV shows poor contrast on both the cell organelles and MWCNTs. However,…graphene layers of MWCNT were clearly visible in the HRTEM image using the high-voltage TEM. The influence of the surrounding biological tissue can be disregarded by the high-energy electrons due to their weak scattering/absorption effect in the tissue. It was indicated that the usage of the high-voltage TEM is quite effective to the atomic structure analysis of nano-crystalline materials in vivo.
Keywords: Low-voltage and high-voltage transmission electron microscopy, high-resolution electron microscopy, multi-wall carbon nanotube, in vivo
Abstract: Magnetic metal particles are known to induce heat energy under an alternating magnetic field (AMF). We developed a local tumor-heating device incorporating an MgFe2 O4 needle for the purpose of mild ablation for cancer treatment. A needle made from sintered MgFe2 O4 particles was embedded in the hepatic or breast tumors. Tumors were then heated by the energy dissipated from the needle exposed to an AMF. We sequentially evaluated histological changes, cellular activity of tumors, and the extent of thermal effect using nicotinamide adenine dinucleotide (NADH) diaphorase and terminal deoxynucleotidyl tranferase-mediated digoxigenin-DUTP nick-end labeling (TUNEL) staining. The mean…temperature of the tumor tissue during heating was about 60°C. Nuclei of the tumor cells became hyper-chromatin immediately after heating. The injured area spread progressively until 3 days after heating; when the area was surrounded by fibroblasts (meaning is not clear). Tumors disappeared after treatment without complications. This is the first time that the complete death of tumor cells has been realized by raising the tumor temperature above 60°C using the heat generated by magnetic metal particles exposed to AMF. This device may be useful in the future for local hyperthemic treatment of human cancers.
Keywords: Inductive heating, magnesium ferrite, cancer treatment, ablation
Abstract: Certain molecules, which are able to directly translocate across phospholipid bilayer membranes (cell or endosormal membrane), can be useful as carriers (vectors) for drags (especially polymeric drags). We have studied the translocationability of the hydroxyapatite nanoparticle–poly-L-arginine complex through the negatively charged phospholipid bilayer membranes by using several instruments. It was confirmed by means of a confocal laser scanning microscopy (CLSM) not only the fact that the complex can translocate through the membranes but also the fact that the complexes were still retained in the inner water layer of the liposome even after the translocation.
Abstract: Synthetic bone cement that has zinc oxide core particles covered with hydroxyapatite (HAP) was developed; that is, the conversion of hopeite, the traditional zinc phosphate cement, into HAP was attempted. Here, hopeite is the final product of the reaction between powders and trituration liquid of the traditional zinc phosphate cement. This cement may have many advantages not only in terms of biological functions but also the setting process of the traditional cement and the mechanical properties of the developed compact if the hopeite can be converted into calcium phosphate (CP). In this study, calcium nitrate solutions of various concentrations were…used for the conversion of hopeite crystals into CP. The products after the solution treatment were analyzed by X-ray diffractometry (XRD), Fourier transform infrared spectrometry (FTIR), and scanning electron microscope (SEM) observation. These results indicated that the converted scholzite crystals could be partially detected. Several types of set zinc phosphate cement with different P/L ratios were arranged. The surface products of the set cement after the solution treatment were analyzed by XRD. However, the crystal phase such as hopeite was not detected except for zinc oxide. The set cement, which was treated with the calcium nitrate solution, was immersed in simulated body fluid (SBF). HAP-like crystals on the set cement could be detected for the specimens immersed for 4 weeks. These findings suggested that the binding phase in the set cement could be converted into HAP by immersion in SBF.
Abstract: We fabricated novel chitosan/hydroxyapatite (HAp) nanocomposites with porous structure by the co-precipitation and porogen leaching method. SEM observation confirmed that the porous chitosan/HAp nanocomposites with 60.6% and 87.1% porosity showed the interconnective pores with pore diameters in the range of 100–200 μm. The composites were found to be mechanically flexible and could be easily formed into any desired shape. The mechanical strength was enhanced by the heat treatment with saturated steam, which was ascribed to the formation of hydrogen bonds between chitosan molecules. The composites subcutaneously implanted in the backs of SD rats for 3 weeks caused little inflammation, and…new blood vessel growth and giant cells were found around the composite accompanied with roughening of the surface due to degradation, showing good biocompatibility and biodegradation.
Abstract: The purpose of this study is to compare in vivo retention of BMP-2 and bone induction in HAp (porosity: 60–80%, pore size: 100–600 μm, sintering temperature: 800°C, surface area: 1 m2 /g) and β-TCP (porosity: 75%, pore size: 100–400 μm, sintering temperature: 1050°C, surface area: 4 m2 /g). We estimated the in vivo release profile of 125 I-labeled BMP-2 and bone induction of hard tissues histologically. The amount of BMP-2 remaining in the β-TCP at 1 day after implantation was 49.6%, while the amount was 34.0% in the HAp. Furthermore, the HAp and β-TCP containing 0.0, 0.05, 0.1, 0.3, 0.5,…1.0, 5.0 μg of BMP-2 were implanted into the back subcutis of 4-week old Wistar rats. At 3 weeks after implantation, the ceramics were explanted and evaluated histologically. The HAp/BMP-2 (5.0 μg) system showed 3.0% in the total volume of bone at 3 weeks, while only in the β-TCP/BMP-2 (5.0 μg) system showed 32.5%. These results indicate that the absorbable β-TCP block may be an effective bioceramic for bone induction to deliver BMP-2 to the site of action.
Abstract: Carbon nanotubes (CNTs) exhibit excellent cell proliferation properties, which can serve as a scaffold for cell culturing. However, there are only a few reports on adhesion of osteoblast-like cells to a CNT sheet. In this study, we investigated adhesion of osteoblast-like cells to single-walled carbon nanotube (SWNT) and multi-walled carbon nanotube (MWNT) sheets and compared these adhesions with that on a cell culture polystyrene dish by using a cell adhesion test and a scanning electron microscope. The MWNT sheets exhibited faster adhesion of cells at an initial stage than SWNT sheets and cell culture polystyrene dish. The number of attached…cells on the MWNT sheets seemed to be greater than on SWNT sheets and cell culture polystyrene. Moreover, the MWNT sheets exhibited both high speed and good capacity for cell adhesion. However, the surface of the MWNT sheets was such that it facilitated cell adherence but hindered the spreading of the attached cells. Interestingly, cell adhesion to CNT sheets was significantly influenced by pre-coating with serum. These results indicate that CNT sheets would play an important role in adsorption of serum proteins, which would consequently facilitate cell adhesion, and that the MWNT sheets have a high cell adhesiveness.
Abstract: Silicone rubbers are widely used as tissue implants because of their flexibility and chemical stability. However, they have limited cellular adhesiveness and may cause problems in the long term. In this study, a coating of carbon nanotubes (CNTs) was applied to silicone rubber to improve its cellular adhesiveness. Scanning electron micrograph of this coating revealed that CNTs had formed a densely packed meshwork; the Ra values and protein adsorption capacity were enhanced. Although the contact angle did not change after coating, it decreased after immersion into a culture medium. After cultivation for 6 d, while Saos-2 cells were hardly…observed on untreated silicone, the cells proliferated on CNT-coated silicone. Thus, CNT coating might be a simple and effective solution to problems associated with silicone implants.
Keywords: Silicone rubber, carbon nanotubes, osteoblast, cell proliferation, protein adsorption