ハイスループット細胞解析のための新しい電気化学プラットホームのデザイン,作製および評価

Tohoku University末永智一課

Modelling of Magnetic Aggregation of Stem Cells in Microfluidics

Individual cells assemble to form multi-cellular aggregates in a hierarchical manner over different length scales to coordinate the tissue functions. Current approaches to control the assembly and patterning of stem cells in 3D, require intrinsic adhesive properties, chemical modifications of cell and material interfaces or engineering intracellular interactions. A particular concern in surface modification of stem cell for adhesion properties, is the possibility of attenuation and inhibition of signalling pathways critical for differentiation of cells. Microfabrication technologies enable extremely fine-tuned culture management by means of control and reproducibility of extracellular stimulus (cues) to the levels unachievable by traditional standard tissue culture. Recent advances in microfabrication technologies and studies in microfluidics demonstrate the usage of magnetic forces that can be broadly applied across multiple length scales to direct individual cells for aggregation at microscales, and have long been used for large scale applications such as sorting and separating population of cells. Recent experiments suggest that magnetic microparticles (magMPs) can be efficiently incorporated in dose-dependent manner in extra-cellular environment of stem cells without any chemical and surface modifications of stem cells and assembly

Microfluidic devices for cell cultivation and proliferation

Microfluidic technology provides precise, controlled-environment, cost-effective, compact, integrated, and high-throughput microsystems that are promising substitutes for conventional biological laboratory methods. In recent years, microfluidic cell culture devices have been used for applications such as tissue engineering, diagnostics, drug screening, immunology, cancer studies, stem cell proliferation and differentiation, and neurite guidance. Microfluidic technology allows dynamic cell culture in microperfusion systems to deliver continuous nutrient supplies for long term cell culture. It offers many opportunities to mimic the cell-cell and cell-extracellular matrix interactions of tissues by creating gradient concentrations of biochemical signals such as growth factors, chemokines, and hormones. Other applications of cell cultivation in microfluidic systems include high resolution cell patterning on a modified substrate with adhesive patterns and the reconstruction of complicated tissue architectures. In this review, recent advances in microfluidic platforms for cell culturing and proliferation, for both simple monolayer (2D) cell seeding processes and 3D configurations as accurate models of in vivo conditions, are examined

UTILIZING DIELECTROPHORESIS TO DETERMINE THE PHYSIOLOGICAL DIFFERENCES OF EUKARYOTIC CELLS

Type 1 diabetes affects over 108,000 children, and this number is steadily increasing. Current insulin therapies help manage the disease but are not a cure. Over a child’s lifetime they can develop kidney disease, blindness, cardiovascular disease and many other issues due to the complications of type 1 diabetes. This autoimmune disease destroys beta cells located in the pancreas, which are used to regulate glucose levels in the body. Because there is no cure and many children are affected by the disease there is a need for alternative therapeutic options that can lead to a cure. Human mesenchymal stem cells (hMSCs) are an important cell source for stem cell therapeutics due to their differentiation capacity, self-renewal, and trophic activity. hMSCs are readily available in the bone marrow, and act as an internal repair system within the body, and they have been shown to differentiate into insulin producing cells. However, after isolation hMSCs are a heterogeneous cell population, which requires secondary processing. To resolve the heterogeneity issue hMSCs are separated using fluorescent- and magnetic-activate cell sorting with antigen labeling. These techniques are efficient but reduce cell viability after separation due to the cell labeling. Therefore, to make hMSCs more readily available for type 1 diabetes therapeutics, they should be separated without diminishing there functional capabilities. Dielectrophoresis is an alternative separation technique that has the capability to separated hMSCs. This dissertation uses dielectrophoresis to characterize the dielectric properties of hMSCs. The goal is to use hMSCs dielectric signature as a separation criteria rather than the antigen labeling implemented with FACS and MACS. DEP has been used to characterize other cell systems, and is a viable separation technique for hMSCs

The Students’ Knowledge, Attitudes, and Behavior in Learning History at Pesantren Buya Hamka

This study aims to determine the implementation stage of history learning process for students at the Pesantren Buya Hamka; the stages of knowledge, attitudes, and behavior of students regarding nationalism and patriotism; and the correlation of leadership variables, school climate, teacher performance, and pesantren culture to history learning and also to students’ knowledge, attitudes, and behavior regarding nationalism and patriotism. This study also aims to find out the significant influence of historical learning variables on knowledge, knowledge variables on attitudes and attitudes on students’ behavior. This study combines survey research quantitative approach with descriptive, correlation, and regression methods. The results show there is a significant correlation between independent variables with historical learning variables and student knowledge variables about nationalism and patriotism. Meanwhile, there is no significant correlation between independent variables and student behavior variables. The results also show only the history of learning variables among the five independent variables that significantly influence the knowledge of nationalism and student patriotism. Student knowledge variables about nationalism and patriotism partially also affect changes in student attitudes, while changes in student attitudes do not affect linearly on changes in student behavior

Cell-cell and cell-medium interactions in the growth of mouse ESCs

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 100-108).Embryonic stem cells serve as powerful models for the study of development and disease and hold enormous potential for future therapeutics. Due to the potential for embryonic stem cells (ESCs) to provide a variety of tissues for use in regenerative medicine, there has been great interest in the identification of factors that govern the differentiation of ESCs into specific lineages. Much of this research builds on previous studies of the role of intercellular signaling in the specification of various cell types in the developing embryo. However, relatively little work has been done on understanding the role of cell-cell communication in the self-renewal of ESCs. In the first part of this thesis I describe the development and testing of new devices for studying intercellular signaling - the nDEP microwell array and the Bio Flip Chip (BFC). We used the BFC to show that cell-cell interaction improves the colony-forming efficiency and the self-renewal of mouse ESCs. Further, we demonstrate that the interaction is at least partly diffusible. In the next part of the thesis I describe our use of more traditional assays to validate the results obtained using the BFC and to further explore the role of diffusible signaling in the survival of mouse ESCs. We demonstrate the existence of an optimal density for 2-day culture of mouse ESCs. Further, we demonstrate that the increase in growth with plating density (103-104 cells/cm2) is at least partly due to the existence of one or more survival-enhancing autocrine factor(s) in mouse ESC cultures, and that one of these factors is Cyclophilin A. Finally, we demonstrate that changes in the low molecular weight composition of the medium are likely responsible for the decrease in growth at high plating densities (>104 cells/cm2). We use a numerical model to show that competition between the positive effect (on growth) of autocrine survival factors and the negative effect of nutrient depletion can account for the observed optimal growth density. Our study provides new insight into the processes underlying, and optimization of, growth in cell types that lack contact inhibition such as cancer cells and stem cells.by Nikhil V. Mittal.Ph.D