Blood supplying is one of the key factors for realizing the large-scale tissue and organ regeneration. One strategy is the use of acellular tissues which have capillary network by nature. In this study, we studied the condition of decellularization and capillary structure maintenance for applying the decellularized liver as the capillary network matrix for nutrient and oxygen supply. Rat liver was decellularized by using several kinds of detergents and high-hydrostatic pressure treatments. The decellularization of the liver was confirmed by hematoxylin-eosin staining. The perfusion of dye and the X-ray μCT scanning were used to confirm the capillary network structure of the decellularized liver. The performance of the decellularized livers as the perfusion base material to supply oxygen was evaluated. The best result was given by HHP treated liver. Oxygen supply through the tunica serosa hepatis of decellularized liver to outside was also capable. These results suggest that the decellularized liver could be applied as capillary network matrix.

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Micropatterning methods using three-dimensional (3D) substrates or scaffolds that reproduce aspects of the in vivo microenvironment could facilitate the engineering of functional tissues for transplantation or more robust experimental models. Cell embedding techniques into 3D scaffolds can be expected for applications such as (1) three-dimensional culture technique mimicking the structure of living tissue closely, (2) efficient differentiation of stem cells, and (3) implantation of biocompatible materials-contained cell. In this study, we focused nerve cells and developed a neuronal network embedding method into 3D scaffolds using an excimer laser that precisely etches the 3D biomaterials. It was then possible to guide neural network formation in laser etched area. Using excimer laser, we succeeded in etching collagen fibers at minimum processing 5 μm in width and culturing Rat hippocampal neuronal networks in laser processing area. In addition, we demonstrated that neuron elongates neurites into the hole that has been processed to the Z-axis. This excimer laser etching in 3D scaffold is useful as cell arrangement technology to the biocompatible material depths.

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A wireless energy transmitting system is required for patient-implanted ventricular assist devices. We developed a wireless power feeding system that uses a large transmitting coil embedded in the floor to send power to a receiving coil implanted between the skin and fat of the human body. To obtain higher transmission efficiency, we examined three types of transmitting coil models (Models 1-3) in this study. The number of turns N and winding interval t of Models 1, 2, and 3 were N = 20, t = 12 mm; N = 10, t = 25.6 mm; and N = 6, t = 46 mm, respectively. We investigated the tradeoff between the self-resonance frequency of the transmitting coil and mutual inductance of the transformer. The results showed that a maximum transmission efficiency of 39.7% (standing position) and 75.8% (seating position) was obtained at 1 MHz with Model 2. Furthermore, the specific absorption rate (SAR), which is an index of the biological effect of the electromagnetic field, electric field E from the transformer of Model 2 and transmitting efficiency when the human body was included were estimated by an electromagnetic simulator. SAR and E were found to be less than the limit value prescribed by International Commission on Non-Ionizing Radiation Protection (ICNIRP) standards when the transmitting power was 15W. Difference of the transmitting efficiency between with and without a human body was less than 10.4%. This confirmed that our transformer can transmit energy to the receiving coil without adverse biological effects.

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An evaluation system for the management of cell culture process is required to noninvasively evaluate the cellular growth potential in the cell culture process. In cell culture process, cell behavior is influenced by the state of the cell potential. Therefore, it is necessary to evaluate accordance with the change of cell behavior. In this study, evaluation method was developed with measuring the cell behavior of observed individual cells at elapse time. The passage culture of HPASMC cells was shown that the ratio of individual cells with fast migration (over 72 μm/hour) decreased with increased of culture passage. Cells in an early culture passage indicated the average projected area increased over time. Moreover, the cell migration flux was newly calculated as evaluation index for quantification of cell growth potential. The migration flux of individual cells decreased with decreased residual number of cell divisions. In conclusions, it was suggested that migration flux can be evaluated cellular potential to measure migration rate and projected area at elapse time in cell culture process. Additionally, it was suggested that cell migration flux was useful for management of cell culture process and quality evaluation.

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