Yes / In this paper, two types of nano carbon materials including 0D nano carbon black and 2D graphene are assembled through electrostatic adsorption to develop smart cement-based composites. Owing to their excellent mechanical, electrical properties and synergistic effect, self-assembled 0D/2D nano carbon materials can form toughening and conductive networks in cement-based materials at low content level and without changing the preparation process of conventional cement-based materials, thus endowing cement-based materials with smart and multifunctional properties including high toughness, self-sensing property to stress/strain and damage, shielding/absorbing property to electromagnetic wave. The developed smart cement-based composites with self-assembled 0D/2D nano carbon materials have promising application in the fields of oil well cementing, structural health monitoring, and electromagnetic protection and anti-electromagnetic pollution. It can therefore conclude that electrostatic self-assembled 0D/2D nano carbon materials provide a simple preparation method and excellent composite effect for developing nano cement-based materials, which can be applied in large-scale infrastructures. / The National Science Foundation of China (51908103) and the China Postdoctoral Science Foundation (2019M651116).

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京都大学 / 新制・課程博士 / 博士(理学) / 甲第24074号 / 理博第4841号 / 新制||理||1692(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 寺西 利治, 教授 島川 祐一, 教授 倉田 博基 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Polymeric nanoparticles have a wide range of applications, particularly as drug delivery and diagnostic agents, and tannins have been regarded as a promising building block for redox and pH responsive systems. Tannins are a class of naturally occurring polyphenols commonly produced by plants and are found in many of our consumables like teas, spices, fresh fruits, and vegetables. Many of the health benefits associated with these foods are a result of their high tannin contents and the many different types of tannins found in various plants have demonstrated therapeutic potentials for conditions ranging from cardiovascular disease and diabetes to ulcers and cancer. Diets rich in tannins have been associated with lower blood pressure in patients with hypertension. The plurality of phenols in tannins also makes them powerful antioxidants and as a result, there is a lot of interest in taking advantage of their self-assembling abilities to make redox and pH responsive drug delivery systems. However, the benefit of natural tannins is limited by their instability in physiological conditions. Furthermore, there is limited control over molecular weight and reactivity of the phenolic content of plant extracts. Herein we report the novel synthesis of pseudotannins with control over molecular weight and reactivity of phenolic moieties. These pseudotannins have can form nanoscale interpolymer complexes under physiological conditions and have demonstrated antioxidative potential. Furthermore, pseudotannin IPCs have been shown to be responsive to physiologically relevant oxidation as well as the ability to easily incorporate cell targeting peptides, fluorescent tags, and MRI contrast agents. The work presented here describes how pseudotannins would be ideally suited to minimally invasive techniques for diagnosing atherosclerotic plaques and targeting triple negative breast cancer. We demonstrate that pseudotannin can very easily and quickly form nanoscale particles that are small enough to be uptaken into mammalian cells. Furthermore, by self-assembling with gadolinium, pseudotannins can effectively attenuate the signal of gadolinium based MRI contrast agents. This in conjunction with oxidation responsive decomplexation could be a viable option for diagnosing the severity and risk of rupture of atherosclerotic plaques. Also, we demonstrate that pegylated compounds can easily be incorporated into pseudotannin nanoparticles to impart cell targeting functionality. The subsequent uptake of pseudotannin nanoparticles into breast cancer cells demonstrated the ability to increase their sensitivity to UV radiation. The creation of synthetic tannin-like polymers leads to directly to making a variety of self-assembling, stimuli responsive, and bioactive nanoparticles well-suited for various biomedical applications. / Bioengineering

There is a need for the development of new technologies for the early detection of disease. Diverse initiatives are underway in academia and the pharmaceutical and biotechnology industries to develop highly-sensitive, high-throughput methods to detect disease-relevant biomarkers at the single-cell level. Biomarkers can define the progress of a disease or efficacy of disease treatment, and can include nucleic acids (RNA, DNA), proteins, small molecules, or even specific cells. While discovery research in this area is accelerating, there are a number of current experimental limitations. Most existing methodologies require a relatively large sample size. Also, amplification-based detection technologies are destructive to sample, and errors in amplification can occur, leading to an incorrect diagnosis. Nanomaterial-based devices (nanodevices) offer the promise of label-free, amplification-free detection strategies. Such nanodevices could allow analysis of minute biological samples without the requirement for amplification or incorporation of reporter groups. Loss of sample, due to handling and processing would be minimized and the sample could be recovered for further analysis. Atomic force microscopy (AFM) allows topographic imaging and compressibility/elasticity measurement of biomolecules on solid supports. AFM can enable assays of ligand binding with single molecule detection capability. Certain nucleic acid types, in particular double-stranded (ds) RNA, can act as a biomarker for specific cancers (e.g. leukemia) and viral infection. dsRNA also is of interest since it is a conserved structural feature of precursors to gene-regulatory RNAs, including micro (mi) RNAs and short interfering (si) RNAs. This project demonstrates a single-step, label-free, amplification-free approach for detecting the interaction of biomolecules that bind and/or process dsRNA, using a nanomanipulated, self-assembled monolayer (SAM) of a ds[RNA-DNA] chimera as imprinting matrix, a reference nuclease as imprinting agent, and AFM for imprint-readout. The action of the dsRNA-specific enzyme, ribonuclease III (RNase III), as well as the binding of an inactive, dsRNA-binding RNase III mutant can be permanently recorded by the input-responsive action of a restriction endonuclease that cleaves an ancillary reporter site within the dsDNA segment. The resulting irreversible height change of the arrayed ds[RNA-DNA] chimera, as measured by atomic force microscopy, provides a distinct digital output for each type of input. These findings provide the basis for developing imprinting-based nano-biosensors, and reveal the versatility of AFM as a tool for characterizing the behaviour of highly-crowded biomolecules at the nanoscale. RNA-DNA heteroduplexes are biomarkers for specific inflammatory conditions of genetic origin, and also are the product of capture of an RNA (e.g., miRNA) by a complementary DNA sequence. The approach used here to detect RNA-DNA hybrids is based on the ability of alkylthiol-modified ssDNA molecules to form monolayers and nanomatrices on gold surfaces (as described above) with density-dependent thickness, which increases upon formation of RNA-DNA hybrids following addition of a complementary oligoribonucleotide. Changes in hybrid matrix thickness can be measured by AFM, using a reference monolayer. RNA-DNA hybrid formation as well as subsequent processing by RNase H can be observed as a height increase or decrease, respectively, of the monolayer. When Mg2+ is omitted to prevent RNA cleavage, but not protein binding, a significant height increase is observed. The height increase is not observed with the corresponding ssDNA or ssRNA nanomatrices, and only occurs with nanomatrices having a hybrid density above a defined threshold. The data indicate formation of a stable multimeric RNase H assembly on the hybrid nanomatrix which provides a robust signal that is nondestructive to the RNA. The implications of these findings are discussed with respect to development of novel detection methodologies for RNA, dsRNA, and RNA-DNA hybrids. / Chemistry

The reactivity of chemical warfare agents (CWAs) and CWA simulants on organic and oxide surfaces is not currently well understood, but is of substantial importance to the development of effective sensors, filters and sorbent materials. Polyurethane coatings are used by the armed forces as chemical agent resistive paints to limit the uptake of CWAs on surfaces, while the use of metal oxides has been explored for decontamination and protection purposes. To better understand the chemical nature of the interactions of organophosphonate simulants with these surfaces, an ultra-high vacuum environment was used to isolate the target interactions from environmental gaseous interferences. The use of highly-characterized surfaces, coupled with molecular beam and dosing capabilities, allows for the elucidation of adsorption, desorption, and reaction mechanisms of CWA simulants on a variety of materials. Model urethane-containing organic coatings were designed and applied toward the creation of well-ordered thin films containing carbamate linkages. In addition, novel trisilanolphenyl-polyhedral oligomeric silsesquioxane (POSS) molecules were used to create Langmuir-Blodgett films containing reactive silanol groups that have potential use as sensors and coatings. The uptake and reactivity of organophosphonates and chlorophosphates on these surfaces is the focus of this study. Surfaces were characterized before and after exposure to the phosphates using a number of surface sensitive techniques including: contact angle goniometry, reflection-absorption infrared spectroscopy (RAIRS), X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD) measurements. In conjunction with surface probes, uptake coefficients were monitored according to the King and Wells direct reflection technique. The integration of these analytical techniques provides insight and direction towards the design of more effective chemical agent resistant coatings and aids in the development of more functional strategies for chemical warfare agent decontamination and sensing. / Ph. D.