Published papers

We newly developed high-performance blood coagulation nanofibres using Polycaprolactone (PCL) including Calcium carbonate (CaCO3) and beta-chitosan. The most important feature for a wound dressing is that it is harmless to the human body. Here, we fabricated the nanofibre using all human-safe materials. We used a PCL nanofibre mat as a substrate and then synthesized artificial CaCO3 from sodium carbonate and calcium chloride. The CaCO3 was then added to the fibre solution to create PCL/CaCO3 nanofibres. We coated PCL and PCL/CaCO3 nanofibres with b-chitosan as a hemostatic material via a spray method. For the more uniform coating, we used ultrasonic spray coating method and then compared the blood coagulation abilities of the PCL and PCL/CaCO3 nanofibres. We found that the PCL/CaCO3 nanofibres sprayed with beta-chitosan had a greater effect on blood coagulation than the PCL nanofibres. In the result of animal experiment, beta-chitosan have a key role in changing of surface wettability from hydrophobic to hydrophilic. Moreover, this is contributed to enhance blood coagulability. PCL/CaCO3 nanofibres sprayed with beta-chitosan therefore offer promise in medical applications. (C) 2017 Elsevier Ltd. All rights reserved.

© 2020 Elsevier B.V. Motile bacteria are able to penetrate in the distal areas of blood vessel, which makes bacteria attractive to researchers as a drug delivery vehicle carrying anti-cancer drugs to tumors. Not only therapeutic bacteria show wide anti-tumor effect but also the combination of therapeutic bacteria and conventional chemotherapy leads to dramatically large synergetic effect. We provide a mechanistic understanding of enhanced drug delivery in tumors by co-administration of chemotherapeutic agents and therapeutic bacteria. In this work, simultaneous delivery of C. novyi-NT and chemotherapeutic agents in tumors is mathematically modeled. Simulated doxorubicin concentration in tumors after Doxil administration with or without bacteria agreed reasonably well with experimental literature. Simulated doxorubicin concentration in tumors by the combination of Doxil and C. novyi-NT is over twice higher than that of Doxil alone. This enhanced doxorubicin concentration in tumors is due to the degradation of extracellular matrix of collagen by bacterial proteolytic activity, which increases hydraulic conductivity of interstitium, reduces interstitial fluid pressure, and thus increases convection through vessel walls. Additionally, it alleviates solid stress, which decompresses blood vessels, and thus increases vessel density. On the other hand, simulated doxorubicin concentration in tumors for non-liposomal free-doxorubicin is not enhanced by C. novyi-NT because vascular permeability of free-doxorubicin is larger than Doxil, and thus increased but relatively small convection across vessel walls is offset by the efflux due to increased interstitial flow. A strategy to further enhance this combination therapy is discussed along with sensitivity analysis.

©2018 by The American Association of Immunologists,Inc. The treatment of skin with a low-power continuous-wave (CW) near-infrared (NIR) laser prior to vaccination is an emerging strategy to augment the immune response to intradermal vaccine, potentially substituting for chemical adjuvant, which has been linked to adverse effects of vaccines. This approach proved to be low cost, simple, small, and readily translatable compared with the previously explored pulsed-wave medical lasers. However, little is known on the mode of laser-tissue interaction eliciting the adjuvant effect. In this study, we sought to identify the pathways leading to the immunological events by examining the alteration of responses resulting from genetic ablation of innate subsets including mast cells and specific dendritic cell populations in an established model of intradermal vaccination and analyzing functional changes of skin microcirculation upon the CW NIR laser treatment in mice. We found that a CW NIR laser transiently stimulates mast cells via generation of reactive oxygen species, establishes an immunostimulatory milieu in the exposed tissue, and provides migration cues for dermal CD103+ dendritic cells without inducing prolonged inflammation, ultimately augmenting the adaptive immune response. These results indicate that use of an NIR laser with distinct wavelength and power is a safe and effective tool to reproducibly modulate innate programs in skin. These mechanistic findings would accelerate the clinical translation of this technology and warrant further explorations into the broader application of NIR lasers to the treatment of immune-related skin diseases. The Journ Al of Immunology, 2018, 201: 3587-3603.

To preserve the fertility of young female cancer patients, ovarian tissue cryopreservation and transplantation have been investigated as next-generation reproductive medical technologies. Noninvasive visualization of follicles in ovarian tissue and cryopreservation of higher density tissue is essential for effective transplantation. We proposed the use of optical coherence tomography (OCT) that can noninvasively visualize the internal structure of the ovarian tissue. However, a method for quantifying cell density has not yet been established because of the lack of available techniques to visualize follicles noninvasively. We proposed the use of a convolutional neural network (CNN) to extract small features from medical images as an image analysis method to automatically detect follicles from the obtained OCT images. First, we collected a total of 13 ovarian tissues from four-day-old mice and acquired OCT images using a full-field-type OCT. Then, the acquired images were analyzed using three detection methods: filter processing, filter processing combined with the CNN, and only CNN. Finally, to verify the detection accuracy of each method, the detection rate and precision were calculated by taking the doctor's detection as the correct result. The results showed that the detection method only using CNN achieved a detection rate of 0.81 and precision of 0.67; this indicated that follicles could be effectively detected using our proposed method. Furthermore, it is quantitatively evident that the density of follicles from the surface layer to the deep region differs depending on the tissue. In the future, these results could be used to detect follicles in tissues of different maturation stages and quantify follicles three-dimensionally, further accelerating next-generation reproductive medicine.

Objective: Subarachnoid hemorrhage (SAH) causes cerebral ischemia and drastically worsens the clinical status at onset. However, the arterial flow is surprisingly well maintained on the cerebral surface. We investigated cortical microcirculatory changes in the super acute phase of SAH using two-photon laser scanning microscopy (TPLSM). Methods: SAH was induced at the skull base in 10 mice using a prone endovascular perforation model. Before SAH, and I, 2, 5,10, 20,30 and 60 min after SAH, the cortical microcirculation was observed with TPLSM through a cranial window. Diameters of penetrating and precapillary arterioles were measured and red blood cell (RBC) velocities in precapillary arterioles were analyzed using a line-scan method after administration of Q-dot 655 nanocrystals. Results: One minute after SAH, RBC velocity and flow in precapillary arterioles drastically decreased to <20% of the pre-SAH values, while penetrating and precapillary arterioles dilated significantly. Subsequently, the arterioles either dilated or constricted inconsistently for 60 min with continual decreases in RBC velocity and flow in the arterioles, suggesting neurovascular dysfunction. Conclusion: SAH caused sudden worsening of the cortical arteriolar velocity and flow at onset. The neurovascular unit cannot function sufficiently to maintain cortical microcirculatory flow in the super acute phase of SAH. (C) 2016 Elsevier B.V. All rights reserved.

To measure erythrocyte deformability in vitro, we made transparent microchannels on a crystal substrate as a capillary model. We observed axisymmetrically deformed erythrocytes and defined a deformation index directly from individual flowing erythrocytes. By appropriate choice of channel width and erythrocyte velocity, we could observe erythrocytes deforming to a parachute-like shape similar to that occurring in capillaries. The flowing erythrocytes magnified 200-fold through microscopy were recorded with an image-intensified high-speed video camera system. The sensitivity of deformability measurement was confirmed by comparing the deformation index in healthy controls with erythrocytes whose membranes were hardened by glutaraldehyde. We confirmed that the crystal microchannel system is a valuable tool for erythrocyte deformability measurement. Microangiopathy is a characteristic complication of diabetes mellitus, A decrease in erythrocyte deformability may be part of the cause of this complication. In order to identify the difference in erythrocyte deformability between control and diabetic erythrocytes, we measured erythrocyte deformability using transparent crystal microchannels and a high-speed video camera system. The deformability of diabetic erythrocytes was indeed measurably lower than that of erythrocytes in healthy controls. This result suggests that impaired deformability in diabetic erythrocytes can cause altered viscosity and increase the shear stress on the microvessel wall. (C) 2001 Academic Press.

In a hepatic lobule, different sets of metabolic enzymes are expressed in the periportal (PP) and pericentral (PC) regions, forming a functional zonation, and the oxygen gradient is considered a determinant of zone formation. It is desirable to reproduce lobular microenvironment in vitro, but incubation of primary hepatocytes in conventional culture dishes has been limited at fixed oxygen concentrations due to technical difficulties. We designed a cell culture microdevice with an oxygen gradient to reproduce the hepatic microenvironment in vitro. The oxygen gradient during cell culture was monitored using a laser-assisted phosphorescence quenching method, and the cellular oxygen consumption rate could be estimated from changes in the gradient. Culture medium was continuously exchanged through microchannels installed in the device to maintain the oxygen gradient for a long term without transient hyper-oxygenation. The oxygen consumption rates of hepatocytes at 70.0 mmHg and 31.4 mmHg of partial oxygen pressure, which correspond to PP and PC regions in the microdevice, were 3.67 x 10(-10) and 3.15 x 10(-10) - mol/s/10(6) cells, respectively. Antimycin A changed the oxygen gradient profile, indicating that cellular respiration can be estimated during cell culture. RT-PCR analysis of hepatocytes cultured under the oxygen gradient showed that mRNA expression of PEPCK and GK significantly increased in culture areas corresponding to PP and PC regions, respectively. These results indicate that the developed microdevice can reproduce the hepatic lobular microenvironment. The oxygen gradient in the microdevice can be closely controlled by changing the sizes of gas channels and the ambient oxygen concentration around the device; therefore, it could be expected to mimic the oxygen gradient of various organs, and it may be applicable to other pathological models. (C) 2014 Elsevier Inc. All rights reserved.

Except for histological study, there are currently no suitable techniques available for the detection and identification of primordial follicles in ovary of primary ovarian insufficiency patients who have undetectable AMH levels. Also, the ability to locate and quantify follicles on ovarian cortex strips, without fixation, is valuable for patients who could undergo subsequent successful ovarian tissue transplantation. Although optical coherence tomography (OCT) is a well-established high resolution imaging technique without fixation commonly applied in biomedicine, few reports are available on ovarian tissue imaging. In present study, we established standard OCT follicle images at each developmental stage, including the primordial follicle, and demonstrated the efficacy of OCT to estimate IVF outcome in transplanted mice ovary like ovarian reserve tests. Unfortunately, the current commercial OCT could not be used to accurate follicle count the number of follicles for whole ovary, because the maximum depth of examination was 100 mu m. And we demonstrated the safety of OCT examination, it did not affect IVF outcome and birth defect rate, and reproductive ability. Although there is room for improvement, these findings will be first step to bring OCT examination a step closer to clinical application for measuring true ovarian reserve and localizing follicles.

ラマン分光法は生体分子や細胞を非侵襲的に検出する手法として期待されている．しかし，その散乱光強度は微弱であるため，表面増強ラマン散乱 (Surface Enhanced Raman Scattering: SERS) などによる増強機構を利用することで高感度化される．本研究では，SERS増強場の自在な制御と目的分子の高感度検出を目的として，磁性ナノ粒子に金をコートしたSERS発現用のナノ粒子を作製した． Fe3O4@Au (Micromod) にHAuCl4 とNH2OH・HClを攪拌しながら加える操作を繰り返すことで磁性ナノ粒子に金を複数回コートした．金のコート回数に伴う金と鉄の平均質量比の増加をEDX (Energy Dispersive X-ray spectrometry) 分析から定量した．ラマンマーカーとして4-ATP (4-Aminothiophenol) を金コート磁性ナノ粒子に修飾し，Renishaw製のin Via Raman microscopeを用いて4-ATPのラマンスペクトルを測定した．4-ATPに特徴的な1080cm-1 における信号強度がコート回数によって増減することを明らかにし，また最大強度を得るコート回数を決定した．金コート磁性ナノ粒子は外部磁場により液体中での移動を制御することが可能であり，将来的にはSERS増強場の自在な形成や生体分子の高感度化への応用が期待される．

Noninvasive continuous oxygen measurement in living bodies is important in clinics and basic experiments. Focusing on the phosphorescent-lifetime method which can measure the absolute value of the oxygen concentration, we developed a film type oxygen sensor. A thin oxygen sensing film was prepared by mixing Pd-meso-tetra(4-carboxyphenyl)porphyrin (Pd-TCPP) with Polydimethylsiloxane (PDMS). We report calibration experiments on oxygen partial pressure change by using electrochemiluminescenece (ECL) and LED (Light emitting diode) as light source and electrode characteristics for flexible substrate material. AC voltage was applied to the light source, and the oxygen partial pressure was calculated from phase shift of the light source and phosphorescence. As a result of calibration experiment, we could measure oxygen-partial-pressure with high accuracy by LED. However, ECL excitation showed a phase shift, but measurement accuracy was lower than LED. We will improve the measurement accuracy by improving emission intensity and applied voltage pattern of ECL.

© 2018, The Author(s). Purpose: The purpose of this study was to evaluate the possible clinical application of optical coherence tomography for assessing ovarian reserve in individual specimens of human ovarian tissue for fertility preservation. Methods: Ovarian tissue examination by optical coherence tomography was performed before ovarian tissue cryopreservation. Three of the four subjects had hematological disease or cancer, and they faced a threat to their fertility due to impending chemotherapy. One patient underwent ovarian tissue extraction for in vitro activation of dormant follicles as fertility treatment. Results: The current full-field optical coherence tomography technique can detect primordial follicles in non-fixed and non-embedded human ovarian tissue. These images are well correlated with histological evaluation and the ovarian reserve test, including follicle counts. Conclusion: It was demonstrated that optical coherence tomography could assess localization of primordial follicles and ovarian reserve in specimens of non-fixed human ovarian cortex, although optimization for examination of human ovarian tissue is needed for clinical application. Additionally, this technique holds the possibility of assessing the ovarian reserve of patients with unevaluable ovarian reserve. Trial registration number: UMIN000023141.

© 2020 by ASME. Significance: Photobiomodulation is a well-established therapeutic modality. However, the mechanism of action is poorly understood, due to lack of research in the causal relationship between the near-infrared (NIR) light irradiation and its specific biological effects, hindering broader applications of this technology. Aim: Since biological chromophores typically show several absorption peaks, we determined whether specific effects of photobiomodulation are induced with a combination of two wavelengths at a certain range of irradiance only, rather than a single wavelength of NIR light. Approach: In order to analyze a wide array of combinations of multispectral NIR light at various irradiances efficiently, we developed a new optical platform equipped with two distinct wavelengths of NIR lasers by high-throughput multiple dosing for single-cell live imaging. Two wavelengths of 1064 and 1270 nm were selected based on their photobiomodulatory effects reported in the literature. Results: A specific combination of wavelengths at low irradiances (250 to 400 mW/cm2 for 1064 nm and 55 to 65 mW/cm2 for 1270 nm) modulates mitochondrial retrograde signaling, including intracellular calcium and reactive oxygen species in T cells. The time-dependent density functional theory computation of binding of nitric oxide (NO) to cytochrome c oxidase indicates that the illumination with NIR light could result in the NO release, which might be involved in these changes. Conclusions: This optical platform is a powerful tool to study causal relationship between a specific parameter of NIR light and its biological effects. Such a platform is useful for a further mechanistic study on not only photobiomodulation but also other modalities in photomedicine.

© 2019 Author(s). Early detection of various diseases is expected using surface-enhanced Raman scattering (SERS). For example, a method of labeling an antibody of a disease-related molecule on metal nanoparticles and detecting the SERS signals of the particles bound to the antigen is a promising approach. However, the problems of a slow antigen-antibody reaction and low sensitivity remain unsolved. In this study, we fabricated nanoparticles that can be freely moved using an external magnetic field for rapid antigen-antibody reaction and also nanoengineered the substrate to increase the density of hotspots required for SERS. Gold-coated magnetic nanoparticles (Au-MNPs) with a core-shell structure were prepared by applying multiple coatings of gold onto magnetic iron(II,III) oxide nanoparticles, which were used as the core. A neodymium magnet easily moved and converged the Au-MNPs in the solution within a few seconds. In addition, a silver nanoparticle substrate (Ag-NS) with a hexagonal close-packed structure fixed on a polydimethylsiloxane thin film was prepared, and the stable generation of SERS was confirmed over the entire substrate. Upon aggregation of the Au-MNPs onto Ag-NS using a neodymium magnet, the total SERS strength per unit area drastically increased, suggesting that the combination of Au-MNPs and Ag-NS increased the density of the generated hotspots. In future work, with the labeling of antibodies onto Au-MNPs, we expect the proposed method to be applied in the sensitive measurement of biomarkers associated with diseases.

© 2019 The Japan Society of Applied Physics. Oxygen molecules are essential for producing energy in living organisms, meaning that oxygen measurement is required not only in the medical field, but also in research experiments. Porphyrin dyes in polystyrene microparticles were loaded and embedded in dimethylpolysiloxane to create oxygen sensing film. The lifetime of phosphorescence emitted from the film by laser excitation varied depending on the oxygen concentration, and the oxygen partial pressure was quantified from the lifetime. We revealed that the smaller the microparticle size and film thickness, the shorter the response time to the change in oxygen concentration. Next, the film was placed in cell culture microfluidic devices that can form oxygen gradients in the culture layer, and changes of the gradients due to oxygen metabolism of cells and implanted tumor tissues on the sensing film. From this, we demonstrated the effectiveness of the developed oxygen sensing film for medical and biological applications.

© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Efficient and timely delivery of vaccine antigens to the secondary lymphoid tissue is crucial to induce protective immune responses by vaccination. However, determining the longitudinal biodistribution of injected vaccines in the body has been a challenge. Here, the near-infrared (NIR) fluorescence imaging is reported that can efficiently enable the trafficking and biodistribution of vaccines in real time. Zwitterionic NIR fluorophores are conjugated on the surface of model vaccines and tracked the fate of bioconjugated vaccines after intradermal administration. Using an NIR fluorescence imaging system, it is possible to obtain time-course imaging of vaccine trafficking through the lymphatics, observing notable uptake in lymph nodes with minimal nonspecific tissue interactions. Flow cytometry analysis confirmed that the uptake in lymph nodes by antigen presenting cells was highly dependent on the hydrodynamic diameter of vaccines. These results demonstrate that the combination of a real-time NIR fluorescence imaging system and zwitterionic fluorophores is a powerful tool to determine the fate of vaccine antigens. Since such non-specific vaccine uptake causes serious adverse reactions, this method is not only useful for optimization of vaccine design, but also for safety evaluation of clinical vaccine candidates.

© 2020, Biomedical Engineering Society. Purpose: A treatment device without a stent is needed for peripheral stenotic artery treatment. We have proposed short-term heating balloon angioplasty, photo-thermo dynamic balloon angioplasty (PTDBA). Though smooth muscle cells (SMCs) after PTDBA are fixed in a stretched formation in a porcine model, influences of this stimulus on SMCs have not been investigated. SMC migration after vascular dilatation would be related to chronic restenosis. The aim of this study was to examine respiratory activity and recovery ability of SMCs after short-term heating/stretch-fixing in vitro for chronic phase treatment effect discussion. Methods: SMCs on a stretch chamber were heated for 15 s with stretching and fixed in a stretched formation. SMC migration is correlated with the cell respiratory activity. The amount of ATP production was measured using a WST-8 assay for respiratory activity evaluation. The intracellular expression of heat shock protein 70 was measured by an ELISA for recovery ability evaluation. Results: In the case of 60 °C heating, SMC respiratory activity after short-term heating/stretch-fixing decreased drastically in all stretching rates. In the case of 50 °C heating, SMC respiratory activity decreased and then increased. Alternatively, the recovery ability at 60 °C was greater than that at 50 °C. Conclusions: SMCs heated at 60 °C with stretching would have high recovery ability and low respiratory activity related to SMC migration. These results may be important evidence in determining the treatment condition in PTDBA.