Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/aor.14380

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1142/S0219519422500075

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1016/j.ejvsvf.2022.01.004

Language：English   Publishing type：Research paper (scientific journal)  

In this study, we developed a trans-valve left ventricular assist device (LVAD) that unites a rear-impeller axial-flow blood pump (AFBP) and a polymer membrane valve placed at the aortic valve position. The diameter and length of the rear impeller AFBP was 12 and 63 mm, respectively. The polymer membrane valve was similar to the jelly-fish valve consisting of a valve leaflet made of silicone rubber (thickness 0.5 mm), valve ring (diameter: 25 mm), and valve spokes. The trans-valve LVAD was examined in a mock circulation. An implantable pulsatile flow (PF) VAD was connected to an atrial reservoir to simulate the left ventricle (LV), and the Hall valve was worn in the inflow port, and the trans-valve LVAD was placed in the outflow port as an outflow valve. When the motor rotational speed increased to 26 400 rpm, the mean aortic flow increased from 4.2 to 5.3 L/min, mean aortic pressure increased from 83.4 to 100 mm Hg, and mean motor current of the implantable PF VAD decreased from 1.18 to 0.94 A (unloading effect on LV −21%). The energy equivalent pressure increased from 85.2 to 102 mm Hg, and surplus hemodynamic energy (SHE) decreased by −15.4% from the baseline. In conclusion, the trans-valve LVAD has an advantage of preserving pulsatility without any complicated mechanism and is a novel and promising LV support device.

DOI： doi.org/10.1111/aor.13687

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/EMBC46164.2021.9629561

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.11239/jsmbe.Annual59.330

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.11239/jsmbe.Annual59.579

Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (other academic)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1299/jsmedmc.2021.542

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (scientific journal)  

In traditional Chinese pulse diagnosis, the pulses of bilateral radial arteries are palpated by three fingers. In this study, a device that can objectively perform pulse diagnosis using multiple pressure sensors with a cuff was developed. The device has three pressure sensors in series and a cuff to apply external pressure load. Pulse waves were measured using the non-invasive pulse diagnostic device. The relationship of the data obtained from the proposed system with the diagnosis by the traditional method was examined. The study was conducted with the approval of the Ethics Committee in Tohoku University. Twelve adult male subjects were studied. Data of pulse waveforms recorded from the pulse diagnosis device, electrocardiogram, and continuous blood pressure measured at the fingertip were stored and analyzed. The pulse waves of the subjects were categorized as middle pulse, floating pulse, or sunken pulse according to pulse diagnosis in traditional Chinese medicine. Pulse–waveform data were obtained to measure the pulse–pressure changes, which showed different patterns of the rise time at the three measurement sites. Envelope analysis of the pulse waveform from the middle sensor revealed that the peak value of the pulse pressure increased during calculation stress compared to the resting state. It was possible to measure the pulse waves even when a higher external pressure was applied. Objective pulse-wave measurement using a method similar to that in traditional pulse diagnosis was realized, and pulse waveforms were measured using the proposed pulse diagnosis system.

DOI： 10.14326/abe.10.113

Language：English   Publishing type：Research paper (scientific journal)  

Chronic blood trauma caused by the shear stresses generated by mechanical circulatory support (MCS) systems is one of the major concerns to be considered during the development of ventricular assist devices. Large multimers with high-molecular-weight von Willebrand factor (VWF) are extended by the fluid forces in a shear flow and are cleaved by ADAMTS13. Since the mechanical revolving motions in artificial MCSs induce cleavage in large VWF multimers, nonsurgical bleeding associated with the MCS is likely to occur after mechanical hemodynamic support. In this study, the shear stress (~ 600 Pa) and exposure time related to hemolysis and VWF degradation were investigated using a newly designed mechanical shuttle shear flow tester. The device consisted of a pair of cylinders facing the test section of a small-sized pipe; both the cylinders were connected to composite mechanical heads with a sliding-sleeve structure for axial separation during the withdrawing motion. The influence of exposure time, in terms of the number of stress cycles, on hemolysis and VWF degradation was confirmed using fresh goat blood, and the differences in the rates of dissipation of the multimers were established. The plasma-free hemoglobin levels showed a logarithmic increase corresponding to the number of cycles, and the dissipation of large VWF multimers occurred within a few seconds under high shear stress flow conditions.

DOI： 10.1007/s10047-020-01219-3

Language：English   Publishing type：Research paper (scientific journal)  

Extracorporeal membrane oxygenation (ECMO) plays an important role in the coronavirus disease 2019 (COVID-19) pandemic. Management of thrombi in ECMO is generally an important issue; especially in ECMO for COVID-19 patients who are prone to thrombus formation, the thrombus formation in oxygenators is an unresolved issue, and it is very difficult to deal with. To prevent thromboembolic complications, it is necessary to develop a method for early thrombus detection. We developed a novel method for detailed real-time observation of thrombi formed in oxygenators using indocyanine green (ICG) fluorescence imaging. The purpose of this study was to verify the efficacy of this novel method through animal experiments. The experiments were performed three times using three pigs equipped with veno-arterial ECMO comprising a centrifugal pump (CAPIOX SL) and an oxygenator (QUADROX). To create thrombogenic conditions, the pump flow rate was set at 1 L/min without anticoagulation. The diluted ICG (0.025 mg/mL) was intravenously administered at a dose of 10 mL once an hour. A single dose of ICG was 0.25mg. The oxygenator was observed with both an optical detector (PDE-neo) and the naked eye every hour after measurement initiation for a total of 8 hours. With this dose of ICG, we could observe it by fluorescence imaging for about 15 minutes. Under ICG imaging, the inside of the oxygenator was observed as a white area. A black dot suspected to be the thrombus appeared 6-8 hours after measurement initiation. The thrombus and the black dot on ICG imaging were finely matched in terms of morphology. Thus, we succeeded in real-time thrombus detection in an oxygenator using ICG imaging. The combined use of ICG imaging and conventional routine screening tests could compensate for each other's weaknesses and significantly improve the safety of ECMO.

DOI： 10.1111/aor.13999

Language：English   Publishing type：Research paper (scientific journal)  

In roller pumps used for cardiopulmonary bypass (CPB), the degree of blockage within the tube resulting from compression of the tube by the rollers, or the degree of occlusion, is closely related to hemolysis, with both tight occlusive and non-occlusive degrees promoting hemolysis. There are as yet no international standards regarding methods of adjusting occlusiveness, and the amount of mechanical stress exerted upon blood remains unknown. To prevent hemolysis during CPB using roller pumps, there is a need to clarify and quantitatively assess the mechanical stress of the occlusiveness of the roller pump. In this study, we have developed a degree of occlusion quantification system which constructs the flow channel shape within an occluded tube from red optical density images, and we have verified the validity of this system. Utilizing a linear actuator, an acrylic roller and raceway, a solution colored with simulated blood powder, and a 3/8-inch vinyl chloride tube, this system uses a camera to capture red optical density images within an occluded tube and constructs the tube flow channel shape using a formula manipulation system. To verify the accuracy of this system, we compared the thickness of a cross-section of the flow channel constructed with the degree of occlusion quantification system with the thickness of a cross-section of silicone cured under the same occlusion conditions. Our experiments indicated that for areas with a small tube gap, this system can construct highly accurate three-dimensional shapes and obtain quantitative indicators assessing the degree of occlusion.

DOI： 10.1007/s10047-020-01211-x

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

In roller pumps used for cardiopulmonary bypass (CPB), the degree of blockage within the tube resulting from compression of the tube by the rollers, or the degree of occlusion, is closely related to hemolysis, with both tight occlusive and non-occlusive degrees promoting hemolysis. There are as yet no international standards regarding methods of adjusting occlusiveness, and the amount of mechanical stress exerted upon blood remains unknown. To prevent hemolysis during CPB using roller pumps, there is a need to clarify and quantitatively assess the mechanical stress of the occlusiveness of the roller pump. In this study, we have developed a degree of occlusion quantification system which constructs the flow channel shape within an occluded tube from red optical density images, and we have verified the validity of this system. Utilizing a linear actuator, an acrylic roller and raceway, a solution colored with simulated blood powder, and a 3/8-inch vinyl chloride tube, this system uses a camera to capture red optical density images within an occluded tube and constructs the tube flow channel shape using a formula manipulation system. To verify the accuracy of this system, we compared the thickness of a cross-section of the flow channel constructed with the degree of occlusion quantification system with the thickness of a cross-section of silicone cured under the same occlusion conditions. Our experiments indicated that for areas with a small tube gap, this system can construct highly accurate three-dimensional shapes and obtain quantitative indicators assessing the degree of occlusion.

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

We previously reported the development of a new hybrid medical material comprising bio-based materials with high biocompatibility and artificial materials with characteristics of excellent strength and processability. This material shows sufficient biocompatibility and excellent stability in vivo. Moreover, when applied to the surface of an implantable sensor, the biological reaction on the sensor function surface can be well controlled. For commercialization and widespread use of hybrid materials with such superior properties, sterilization and storage are critical considerations, given that hybrid materials must be processed outside the body prior to application as medical materials in vivo, thus posing a risk of contamination despite best efforts. Therefore, the aim of the present study was to establish an optimal sterilization method that will not impair the biocompatibility of the hybrid material. Toward this end, we tested six sterilization methods for the hybrid material: autoclave (121℃, 20 min), dry heat (160℃, 120 min), ethylene oxide gas (37℃, 120 min), hydrogen peroxide plasma (45℃, 45 min), and gamma ray (25 kGy) with and without lyophilization. After sterilization, the material was cultured with vascular endothelial cells to evaluate the engraftment rate, and was observed with light and scanning electron microscopy to determine shape and structure changes. The results demonstrated that gamma sterilization without lyophilization was the best sterilization method for this material, which preserved the collagen network and showed no change in number of adhered vascular endothelial cells compared to the pre-sterilized material. These findings are useful to promote the commercialization of this hybrid material with combined advantages of synthetic and bio-based materials for widespread clinical application in the engineering of artificial organs.

DOI： doi.org/10.14326/abe.9.83

Language：English   Publishing type：Research paper (scientific journal)  

In this study, rear-impeller axial flow blood pumps (RIAFBP) were developed to realize a trans-valve axial ventricular assist device (VAD) which consists of the latter blood pump and a polymer monomembrane aortic valve, such as the jellyfish valve. The motor of the RIAFBP is installed in the left ventricle, and its impeller is placed at the aortic valve position. In the prototype RIAFBP, the rotation of the motor is sustained by polyethylene bushings. The RIAFBP has a length of 50 mm and diameter of 19.6 mm. The miniature RIAFBP has the same construction as that of the prototype; however, it employs a ceramic bearing and fin bearing to improve endurance and to reduce blood stagnation. The miniature RIAFBP has a length of 63 mm and diameter of 12 mm. Both RIAFBPs were examined by an in vitro experiment using a 33% glycerin solution. The prototype RIAFBP achieved a maximum pump outflow of 8.5 L/min against a pump head of 100 mm Hg at a rotational speed of 12 000 rpm. The miniature RIAFBP achieved 7 L/min against a pump head of 70 mm Hg at a rotational speed of 21 600 rpm. In conclusion, the miniature RIAFBP has enough pump performance to realize the trans-valve axial VAD.

DOI： 10.1111/aor.13476

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1126/sciadv.aau2426

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/s41598-018-19480-1

Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (other academic)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/s41598-017-10115-5

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (other academic)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (other academic)  

Event date： 2023.8 - 2023.9

Language：English   Presentation type：Oral presentation (general)  

Event date： 2023.2

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2022.11

Language：Japanese   Presentation type：Poster presentation  

Event date： 2022.11

Language：English   Presentation type：Oral presentation (general)  

Event date： 2022.2

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2022.2

Language：English   Presentation type：Oral presentation (general)  

Event date： 2022.1

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2021.11

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2021.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：千葉県  

Event date： 2021.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：千葉県  

Event date： 2021.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：千葉県  

Event date： 2021.10 - 2021.11

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2021.7

Language：English   Presentation type：Oral presentation (general)  

Event date： 2021.6

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2021.2

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Event date： 2021.2

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2021.1

Language：English   Presentation type：Oral presentation (general)  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2020.11

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Event date： 2020.11

Language：English   Presentation type：Oral presentation (general)  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2020.9

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2020.7

Language：English   Presentation type：Oral presentation (general)  

Event date： 2020.7

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2020.5

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2020.5

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Event date： 2020.5

Language：Japanese   Presentation type：Poster presentation  

Applicant：国立大学法人旭川医科大学、バイオチューブ株式会社

Application no：特願2022-040595  Date applied：2022.3

Country of applicant：Domestic  

Applicant：国立大学法人東京工業大学,国立大学法人東京医科歯科大学,国立大学法人旭川医科大学

Application no：特願2021-167592   Date applied：2021.10

Country of applicant：Domestic  

Application no：2021-111590  Date applied：2021.7

Country of applicant：Domestic  

Application no：2020-145958  Date applied：2020.6

Country of applicant：Domestic  

2022年2月19日に旭川医科大学先進医工学研究センター主催医療の最先端講座を開催し、小中学生を対象とした公開講座をオンラインで開催し、運営した。

Frontiers in Nanotechnology, 2020年のIF=5.750

日本生体医工学会の英文学会誌査読委員

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JSAO（日本人工臓器学会）査読委員

学会運営・方針決定（3,900名）

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IFAO（国際人工臓器学会）論文誌査読

年次大会の方針決定・調整

学会運営（2,700名）