京都大学 / 新制・課程博士 / 博士(工学) / 甲第23231号 / 工博第4875号 / 新制||工||1761(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 浜地 格, 教授 松田 建児, 教授 生越 友樹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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Stimuli-responsive drug delivery materials release their payloads in response to physiological or external cues and are widely reported for stimuli such as pH, temperature, ionic strength, electrical potential, or applied magnetic field. While a handful of reports exist on materials responsive to mechanical stimuli, this area receives considerably less attention. This dissertation therefore explores three-dimensional networks and polymer-metal composites as mechanoresponsive biomaterials by using mechanical force to either trigger the release of entrapped agents or change the conformation of implants. At the nanoscale, shear is demonstrated as a mechanical stimulus for the release of a monoclonal antibody from nanofibrous, low molecular weight hydrogels formed from bio-inspired small molecule gelators. Using their self-healing, shear-thinning properties, mechanoresponsive neutralization of tumor necrosis factor alpha (TNFα) in a cell culture bioassay is achieved, suggesting utility for treating rheumatoid arthritis. Reaching the microscale, mechanical considerations are incorporated within the design of cisplatin-loaded meshes for sustained local drug delivery, which are fabricated through electrospinning a blend of polycaprolactone and poly(caprolactone-co-glycerol monostearate). These meshes are compliant, amenable to stapling/suturing, and they exhibit bulk superhydrophobicity (i.e., extraordinary resistance to wetting), which sustains release of cisplatin >90 days in vitro and significantly delays tumor recurrence in an in vivo murine lung cancer resection model. This polymer chemistry/processing strategy is then generalized by applying it to the poly(lactide-co-glycolide) family of biomedical polymers. As a macroscopic approach, a tunable, tension-responsive multilayered drug delivery device is developed, which consists of a water-absorbent core flanked by two superhydrophobic microparticle coatings. Applied strain initiates coating fracture to cause core hydration and subsequent drug release, with rates dependent on strain magnitude. Finally, macroscopic, shape-changing polymer-composite materials are developed to improve the current functionality of breast biopsy markers. This shape change provides a means to prevent marker migration from its intended site—a current clinical problem. In summary, mechanoresponsive systems are described, ranging from the nano- to macroscopic scale, for applications in drug delivery and biomedical devices. These studies add to the nascent field of mechanoresponsive biomedical materials and the arsenal of drug delivery techniques required to combat cancer and other medical ailments. / 2017-10-27T00:00:00Z

Because of the latest developments in nanotechnology and the need to have new functions, a high demand for innovative materials is created. The technological requirements for new applications cannot be fulfilled by most of the well-developed materials like metals, plastics, or ceramics. Therefore, composite materials that can exhibit better properties in contrast to their single counterpart represents a valuable and interesting alternative for the development of new and more performing functional materials. In the past few years, one of the most rapidly developing fields in materials chemistry is research and development of innovative hybrid materials and nanocomposites having exceptional properties. A significant reason for this is that this group of materials closes the gaps between different scientific fields and brings together the ideal properties of the different disciplines into a single system. Conventional materials like polymers or minerals can be mixed with substances of a different kind, like biological molecules and different chemical functional groups to create unique functional materials with the help of a building block method. Inorganic and organic chemistry, physical and biological sciences are integrated in the search for new recipes in a purely interdisciplinary way to generate unique materials. Compounds that are created frequently have interesting new properties for forthcoming functional materials and technological applications. Natural materials frequently function as a model for these systems and various examples of biomimetic methods can be obtained while generating these hybrid materials. The research and development of these materials is driven by the needs of future technologies. The research carried out in this thesis is entirely based on hybrid organic-inorganic materials; hence, it consists of soft organic/bioorganic section that makes it possible to generate multifunctional materials, whereas the hard inorganic section functions as a rigid and stable platform for developing nanocarriers and imaging agents. A key domain in materials chemistry is the creation of smart materials that have the ability to respond to environmental changes or be triggered on demand. These materials have led to the creation of new technologies, like electroactive materials, electrochromic materials, biohybrid materials, sensors and membranes, etc. The required functionality can be provided by the organic or inorganic components, or from both. In this dissertation, the synthesis, methodology, and creation of three unique organic-inorganic hybrid stimuli responsive systems having targeted features for specific applications are examined. The first example is represented by supramolecular microtoroids created by spontaneous self-assembly of amphiphilic molecules and a hydrophilic polymer (chitosan), in the presence of iron (III) chloride. Light irradiation is the stimulus responsible for assembly/disassembly of this new supramolecular entities. The basis of the photo-response of the microtoroids is the photoreaction of the anthracene derivatives. In order to make these materials bio applicable, the microtoroid size was controlled and narrowed down to nanometers, which has led to our second system called metal organic complexes (MOCs). In this system, chitosan was replaced by PNIPAM polymer at optimized concentrations. The reversible thermo-response of MOCs comes from the phase transition ability of PNIPAM. The third hybrid material is the core-shell system consisting of mesoporous organosilica coated with iron oxide nanoparticles, used for cargo delivery and cell imaging. The magnetic-response of the core-shell system results from the strong magnetic properties of iron oxide nanoparticles, while the presence of PMOs increased its biocompatibility. Our research on such organic-inorganic hybrid materials represents a promising development in the field of materials chemistry. Due to the possibility of mixing various properties in a single material, a variety of combinations regarding possible materials and applications have emerged.

Nanofabrication techniques produce materials with enhanced physicochemical properties through a combination of nanoscale roughness and the use of chemically diverse polymers which enable advanced applications in separation science (air/water purification), tissue engineering, and biosensing. Since the late 1990’s, electrospinning has been extensively studied and utilized to produce nano- to microfiber meshes with 3D porosity on the gram scale. By combining a high surface area to volume ratio and tunable surface chemistry, electrospinning is a facile platform for generating non-woven polymeric fibers for many biomedical and industrial applications. This thesis describes three applications of electrospun nano- and microfiber meshes spun from both commercially available and novel polymer systems for: 1) oil and water separation after an accidental oil spill; 2) ultraviolet light controlled protein and cell patterning throughout 3-dimensional nanofiber meshes; and 3) novel diagnostic platform by combining electrospun nanofiber meshes with solid state nanopores for enhanced single molecule nucleic acid and protein detection. Each application embodies the philosophy that electrospun materials have the potential to solve a wide variety of problems by simply tuning the physicochemical properties and mesh morphologies towards the design requirements for a specific problem. For example, to solve the problem of recovering crude oil after an oil spill while generating a minimal waste burden, a hydrophobic and biodegradable microfiber mesh was designed to repeatedly separate oil and water and naturally biodegrade after use. In order to solve the problem of spatiotemporal placement of cells within a 3-dimensional tissue engineering construct, an ultraviolet light activated mesh was designed to transition from hydrophobic (water impermeable) to hydrophilic (water permeable) upon exposure to ultraviolet light facilitating protein and cell patterning. Finally to address two problems with single molecule solid state nanopore biosensors, namely rapid nucleic acid translocation rates and limited protein identification capabilities, a new biosensor platform was developed based on two novel polymeric systems which were synthesized and electrospun into high surface area nanofiber mesh coatings. / 2018-02-17T00:00:00Z

As achievement gaps for indigenous, low SES, and ethnically diverse students widen, teacher education programs in Hawaii continue to be charged with preparing teachers to meet the needs of an increasingly diverse student population. Despite efforts to expand accreditation diversity requirements for teacher education programs, it is unknown whether these programs provide the preparation needed for teachers to develop culturally responsive teaching self-efficacy. Guided by self-efficacy theory, this mixed methods study examined teacher candidates' culturally responsive teaching self-efficacy (CRTSE) beliefs, their relationships with demographic and other variables, and candidates' perceptions of factors that might affect these beliefs. Teacher candidates (N = 175) in a 4- year urban university teacher education program in Hawaii completed a demographic questionnaire and the CRTSE scale. Follow-up interviews were held with 9 participants who agreed to be interviewed to further expand on the quantitative findings. Correlational analysis suggested that as participants advanced to higher terms in college, their CRTSE increased. Regression analysis found that 2 variables predicted CRTSE scores: participant experiences with diverse students and their diversity course ratings. Interview data were transcribed, open-coded, and thematically analyzed. Qualitative findings appeared to support the quantitative results, including participants' perceptions that having more experiences with diverse students and having more diversity courses better prepares them to teach diverse students. This study is socially impactful because it shows that culturally responsive skills training and related experiences may increase teachers' CRTSE and thereby may contribute to mitigating achievement gaps for diverse students, particularly in Hawaii.

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In this work is the realm of lichens. Lichens are everywhere around us but generally unseen by many people. Lichens adjust and react to the circumstances of its surrounding: humid or dry. The responsive property of the lichens to humidity led to the investigation of this species in combination with the flexible properties of knitted textiles. The knit enhances the lichens’ properties in its stretchable, textural, and color possibilities. While activating the textiles through moisture, there is a change in haptic- and visual expression. Working towards a material library, the transformable properties of the textiles are being explored. Lichen in combination with knit is investigated in four categories: transformation, shape, texture, and dye. The lichen and the knit adapt their role according to the category and demonstrate the potential of their various collaborations in each category. In several countries, lichens are protected due to the increase in air pollution. Through visualizing and emphasizing these precious and unseen species, the changeable textiles aim to activate the viewer in rethinking human’s relationship to nature.

Crossfit is a unique method of physical exercise founded on a specific set of underlying scientific principles. The ultimate goal of Crossfit is to maximize work potential across broad time and modal domains. This project attempts to apply the concepts and principles of Crossfit to architecture to maximize living potential of built environments across broad time and modal domain by means of an architecture that is kinetic, interactive, responsive, and continually reconfigurable. The focus of the project is the design of an approximately 35,000 sf building titled The Motus Center for Kinetic Art Science. The building serves both as an actively used gymnasium and movement studio as well as an interactive museum and gallery of kinetic arts and sciences. The building site is located on Cross Street in Boston, Massachusetts between Hanover Street and Salem Street, in an area known as the Artery Strip.

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