メソポーラス構造を有する非貴金属ホウ化物の合成およびその応用

早大学位記番号:新9149早稲田大

Cell Biological Techniques and Cell-Biomaterial Interactions

Biomaterials play a key role in modern tissue engineering and regenerative medicine. They are expected to take over the function of a damaged tissue in the long term, trigger the self-healing potential of the body, and biodegrade at an appropriate rate. To meet these requirements, it is imperative to understand the cell-biomaterial interactions and develop new cell biotechnologies. The collection of this Special Issue brings together a number of studies portraying the underlying mechanisms of cell-biomaterial interactions

A New Model of Esophageal Cancers by Using a Detergent-Free Decellularized Matrix in a Perfusion Bioreactor

The lack of physiologically relevant human esophageal cancer models has as a result that many esophageal cancer studies are encountering major bottleneck challenges in achieving breakthrough progress. To address the issue, here we engineered a 3D esophageal tumor tissue model using a biomimetic decellularized esophageal matrix in a customized bioreactor. To obtain a biomimetic esophageal matrix, we developed a detergent-free, rapid decellularization method to decellularize porcine esophagus. We characterized the decellularized esophageal matrix (DEM) and utilized the DEM for the growth of esophageal cancer cell KYSE30 in well plates and the bioreactor. We then analyzed the expression of cancer-related markers of KYSE30 cells and compared them with formalin-fixed, paraffin-embedded (FFPE) esophageal squamous cell carcinoma (ESCC) tissue biospecimens. Our results show that the detergent-free decellularization method preserved the esophageal matrix components and effectively removed cell nucleus. KYSE30 cancer cells proliferated well on and inside the DEM. KYSE30 cells cultured on the DEM in the dynamic bioreactor show different cancer marker expressions than those in the static well plate, and also share some similarities to the FFPE-ESCC biospecimens. These findings built a foundation with potential for further study of esophageal cancer behavior in a biomimetic microenvironment using this new esophageal cancer model

Mucin corona delays intracellular trafficking and alleviates cytotoxicity of nanoplastic-benzopyrene combined contaminant

Nanoplastics have recently become a worldwide concern as newly emerging airborne pollutants, which can associate with polycyclic aromatic hydrocarbons (PAHs) and form combined contaminant nanoparticles (CCNPs). After being inhaled in the respiratory system, the CCNPs would first encounter the mucous gel layer being rich in mucin. Herein, polystyrene-benzopyrene (PS@Bap) NPs were prepared as CCNPs model and their interaction with mucin and the resultant biological responses were studied. It was observed that mucin corona stably attached to the CCNPs surface, which significantly altered the fate of the CCNPs in lung epithelial cells (A 549 cell line). The mucin corona would 1) stably adsorbed on PS@Bap at the early stages of endocytosis until degraded during the lysosomal transport and maturation process, 2) delay intracellular trafficking of PS@Bap and the progress of Bap detached from PS, 3) enhance uptake of PS@Bap but reduce the cytotoxicity elicited by PS@Bap, as indicated by cell viability, generation of reactive oxygen species, impairment on mitochondrial function, and further cell apoptosis. In addition, in vivo study also verified the enhanced effect of PS on the development of an acute lung inflammatory response induced by Bap. This study highlights the significance of incorporating the effects of mucin for precisely assessing the respiratory system toxicity of nanoplastics based CCNPs in atmospheric environments

Engineering Vascularized Bone Grafts by Integrating a Biomimetic Periosteum and β‑TCP Scaffold

Treatment of large bone defects using synthetic scaffolds remain a challenge mainly due to insufficient vascularization. This study is to engineer a vascularized bone graft by integrating a vascularized biomimetic cell-sheet-engineered periosteum (CSEP) and a biodegradable macroporous beta-tricalcium phosphate (β-TCP) scaffold. We first cultured human mesenchymal stem cells (hMSCs) to form cell sheet and human umbilical vascular endothelial cells (HUVECs) were then seeded on the undifferentiated hMSCs sheet to form vascularized cell sheet for mimicking the fibrous layer of native periosteum. A mineralized hMSCs sheet was cultured to mimic the cambium layer of native periosteum. This mineralized hMSCs sheet was first wrapped onto a cylindrical β-TCP scaffold followed by wrapping the vascularized HUVEC/hMSC sheet, thus generating a biomimetic CSEP on the β-TCP scaffold. A nonperiosteum structural cell sheets-covered β-TCP and plain β-TCP were used as controls. In vitro studies indicate that the undifferentiated hMSCs sheet facilitated HUVECs to form rich capillary-like networks. In vivo studies indicate that the biomimetic CSEP enhanced angiogenesis and functional anastomosis between the in vitro preformed human capillary networks and the mouse host vasculature. MicroCT analysis and osteocalcin staining show that the biomimetic CSEP/β-TCP graft formed more bone matrix compared to the other groups. These results suggest that the CSEP that mimics the cellular components and spatial configuration of periosteum plays a critical role in vascularization and osteogenesis. Our studies suggest that a biomimetic periosteum-covered β-TCP graft is a promising approach for bone regeneration

Effects of Mechanical Stress on the in vitro Degradation of Porous Composite Scaffold for Bone Tissue Engineering

Abstract. In bone tissue engineering, porous scaffolds served as the temporary matrix are often subjected to mechanical stress when implanted in the body. Based on this fact, the goal of this study was to examine the effects of mechanical loading on the in vitro degradation characteristics and kinetics of porous scaffolds in a custom-designed loading system. Porous Poly(L-lactic acid)/β-Tricalcium Phosphate (PLLA/β-TCP) composite scaffolds fabricated by using solution casting/compression molding/particulate leaching technique (SCP) were subjected to degradation in simulated body fluid (SBF) at 37°C for up to 6 weeks under the conditions: with and without static compressive loading, respectively. The results indicated that the increase of the porosity and decrease of the compressive strength under static compressive loading were slower than that of non-loading case, and so did the mass loss rate. It might be due to that the loading retarded the penetration, absorption and transfer of simulated body fluid. These data provide an important step towards understanding mechanical loading factors contributing to degradation

Modeling vascularized bone regeneration within a porous biodegradable CaP scaffold loadedwith growth factors,”Biomaterials

a b s t r a c t Osteogenetic microenvironment is a complex constitution in which extracellular matrix (ECM) molecules, stem cells and growth factors each interact to direct the coordinate regulation of bone tissue development. Importantly, angiogenesis improvement and revascularization are critical for osteogenesis during bone tissue regeneration processes. In this study, we developed a three-dimensional (3D) multiscale system model to study cell response to growth factors released from a 3D biodegradable porous calcium phosphate (CaP) scaffold. Our model reconstructed the 3D bone regeneration system and examined the effects of pore size and porosity on bone formation and angiogenesis. The results suggested that scaffold porosity played a more dominant role in affecting bone formation and angiogenesis compared with pore size, while the pore size could be controlled to tailor the growth factor release rate and release fraction. Furthermore, a combination of gradient VEGF with BMP2 and Wnt released from the multi-layer scaffold promoted angiogenesis and bone formation more readily than single growth factors. These results demonstrated that the developed model can be potentially applied to predict vascularized bone regeneration with specific scaffold and growth factors. Published by Elsevier Ltd

A Study of Bone-Like Apatite Formation on β-TCP/PLLA Scaffold in Static and Dynamic Simulated Body Fluid

Abstract. The ability of apatite to form on the surface of biomaterials in simulated body fluid (SBF) has been widely used to predict the bone-bonding ability of bioceramic and bioceramic/polymer composites in vivo. Porous β-tricalcium phosphate/poly(L-lactic acid) (β-TCP/PLLA) composite scaffold was synthesized by new method. The ability of inducing calcium phosphate (Ca-P) formation was compared in static simulated body fluid(sSBF) and dynamic simulated body fluid (dSBF). The Ca-P morphology and crystal structures were identified using SEM, X-ray diffraction and Fourier transform infrared (FT-IR) spectroscopy. The results showed that the typical features of bone-like apatite formation on the surface and the inner pore wall of β-TCP/PLLA. Ca-P formation on scaffold surfaces in dSBF occurred slower than in sSBF and was more difficult with increasing flow rate of dSBF. The ability of apatite to form on β-TCP/PLLA was enhanced by effect of each other that has different degradable mechanism. Porous β-TCP/PLLA composite scaffold indicates good ability of Ca-P formation in vitro