Kousuke Tsuchiya

Kousuke Tsuchiya
Kyoto University | Kyodai · Department of Material Chemistry

PhD

About

112
Publications
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1,158
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Publications

Publications (112)
Article
Targeted delivery of genes to specific plant organelles is a key challenge for fundamental plant science, plant bioengineering, and agronomic applications. Nanoscale carriers have attracted interest as a promising tool for organelle‐targeted DNA delivery in plants. However, nanocarrier‐mediated DNA delivery in plants is severely hampered by the bar...
Article
Targeted delivery of genes to specific plant organelles is a key challenge for fundamental plant science, plant bioengineering, and agronomic applications. Nanoscale carriers have attracted interest as a promising tool for organelle‐targeted DNA delivery in plants. However, nanocarrier‐mediated DNA delivery in plants is severely hampered by the bar...
Article
Full-text available
The delivery of genetic material into plants has been historically challenging due to the cell wall barrier, which blocks the passage of many biomolecules. Carbon nanotube-based delivery has emerged as a promising solution to this problem and has been shown to effectively deliver DNA and RNA into intact plants. Mitochondria are important targets du...
Article
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Genetic engineering of economically important traits in plants is an effective way to improve global welfare. However, introducing foreign DNA molecules into plant genomes to create genetically engineered plants not only requires a lengthy testing period and high developmental costs but also is not well-accepted by the public due to safety concerns...
Article
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Poly(l-serine) (polySer) has tremendous potential as a polypeptide-based functional material due to the utility of the hydroxyl group on its side chain; however, tedious protection/deprotection of the hydroxyl groups is required for its synthesis. In this study, polySer was synthesized by the chemoenzymatic polymerization (CEP) of l-serine ethyl es...
Article
A telechelic-type polyalanine was doped in silkworm silk fibroins to prepare reinforced composite fibers, which exhibited 42% and 51% higher mechanical properties than silk-only fibers in terms of tensile strength and toughness, respectively.
Article
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The polyion complex vesicle (PICsome) is a promising platform for bioactive molecule delivery as well as nanoreactor systems. In addition to anionic and cationic charged blocks, a hydrophilic poly(ethylene glycol) (PEG) block is mostly employed for PICsome formation; however, the long-term safety of the PEG component in vivo is yet to be clarified....
Article
Full-text available
DNA-free genome editing using Cas9 ribonucleoprotein is advantageous because it introduces fewer potential undesirable genetic modifications than comparable methods. Here, we show a direct protein delivery system for plants using a cell-penetrating peptide-displayed polyion complex vesicle, CPP-PICsome, as a biological nanocarrier. With this system...
Article
In the genetic modification of plant cells, the mitochondrion is an important target in addition to the nucleus and plastid. However, gene delivery into the mitochondria of plant cells has yet to be established by conventional methods, such as particle bombardment, because of the small size and high mobility of mitochondria. To develop an efficient...
Article
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The growth of lamellar crystals has been studied in particular for spherulites in polymeric materials. Even though such spherulitic structures and their growth are of crucial importance for the mechanical and optical properties of the resulting polymeric materials, several issues regarding the residual stress remain unresolved in the wider context...
Article
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Direct delivery of enzymes into intact plants using cell-penetrating peptides (CPPs) is an attractive approach for modifying plant functions without genetic modification. However, by conventional methods, it is difficult to maintain the enzyme activity for a long time because of proteolysis of the enzymes under physiological conditions. Here, we de...
Article
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Diphenyl acetylene derivatives containing various polymeric components have been designed as new Raman imaging probes. These are taken up by plant cells via different pathways, and the internalization of exogenous molecules can be visualized.
Article
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Oligoproline-containing peptides, GPPG and GPPPG, were designed and developed for nanoparticle-based delivery platforms, and their degradation is triggered by reactive oxygen species (ROS). Peptides containing more than two consecutive proline residues were found to be cleavable in 1 mM of ROS generated by hydrogen peroxide in the presence of CuSO4...
Article
Owing to their diverse functions and tunable physicochemical properties, peptides are promising alternatives to the conventional gene delivery tools that are available for plant systems. However, peptide-mediated gene delivery is limited by low transfection efficiency in plants because of the insufficient cytosolic translocation of DNA cargo. Here,...
Article
Full-text available
Almost all natural proteins are composed exclusively of L-amino acids, and this chirality influences their properties, functions, and selectivity. Proteases can recognize proteins composed of L-amino acids but display lower selectivity for their stereoisomers, D-amino acids. Taking this as an advantage, D-amino acids can be used to develop polypept...
Article
Cell-penetrating peptides (CPPs) have been widely utilized as efficient molecular tools for the delivery of bioactive cargoes such as peptides, proteins, and genetic material. However, to improve their versatility as tools in biological environments, the resistance of CPPs to enzymatic degradation and their structural stability must be improved to...
Article
Full-text available
A polypeptide with a GlyHisGly repeating sequence containing zwitterionic structures that effectively interact with cellulose was synthesized by chemoenzymatic polymerization followed by postfunctionalization of the side chains of the His residues to afford imidazolium butyrate. The resulting zwitterionic polypeptide effectively dissociated bundles...
Article
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Polypeptides are used as building blocks that assemble into polymeric hierarchical architectures with various functionalities based on their amino acid sequences. Chemoenzymatic polymerization using a protease as a catalyst allows us to synthesize peptides with various primary structures in an environmentally benign way. In this work, we performed...
Article
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Polypeptides containing periodic aromatic residues, 4-aminobenzoic acid (Abz), in their main chains were synthesized via papain-catalyzed chemoenzymatic polymerization of tripeptide ester monomers under moderate conditions in aqueous buffers. The secondary structures of the Abz-containing polypeptides were investigated by IR and wide-angle X-ray di...
Article
Natural silkworm silks have been applied to reinforce epoxy resin to achieve sub-ambient and impact toughness in the composite. However, the molecular interactions at the silk fibre-matrix interface of the composite are poorly understood. In this work, silk fibroin extracted from Bombyx mori silk is blended with an epoxy resin polymer system to stu...
Article
Chemoenzymatic peptide synthesis is an efficient and clean method to generate polypeptides for new applications in the fields of biomedical and functional materials. However, this enzyme-mediated synthesis is dependent on the reaction rate of the protease biocatalyst, which is essentially determined by the natural substrate specificity of the enzym...
Preprint
Full-text available
Efficient intracellular delivery of biomolecules is important for many different biological and biotechnological applications in living organisms, and is a prerequisite for certain types of fundamental and applied research. One major challenge is the delivery of unmodified, functional cargoes in a simple, time-efficient, and high-throughput manner....
Chapter
Proteases (EC 3.4), enzymes originally used to cleave the amide bonds of proteins by hydrolysis, have been utilized for the enzymatic synthesis of peptide compounds. This enzymatic synthesis of polypeptides is a biomass-based, environmentally benign, atom-economical, and stereo-/regioselective method that can replace petroleum-derived chemical poly...
Article
Full-text available
In this study, we prepared silkworm silk films with fluorinated polypeptide coatings on their surface to achieve water-repellent silk materials. The silk films were smoothly and uniformly coated with the fluorinated polypeptides to give a transparent film. The contact angles of water droplets on the polypeptide-coated silk films were measured to in...
Article
Introducing exogenous genes into plant cells is essential for a wide range of applications in agriculture and plant biotechnology fields. Cationic peptide carriers with cell-penetrating and DNA-binding domains successfully deliver exogenous genes into plants. However, their cell-penetrating activity may be attenuated by undesired electrostatic inte...
Article
Full-text available
Proline and valine exist in repetitive motifs in various structural proteins and play an important role in their physiological functions. Herein, we synthesized polypeptides that consist of di- and tri-peptide motifs containing proline and valine via chemoenzymatic polymerization. Di- and tri-peptide ethyl esters (ValGly-OEt, GlyProGly-OEt, and Val...
Article
Full-text available
Spider dragline silks have attracted intensive attention as eco-friendly tough materials because of their excellent mechanical property and biomass-based origin. Composite films based on a recombinant spider dragline silk protein (ADF3) from Araneus diadematus were prepared by doping with linear or telechelic poly(L-alanine) (L- or T-polyA, respect...
Chapter
Chemoenzymatic polymerization utilizing the aminolysis reaction catalyzed by proteases in aqueous solution is a useful method to synthesize various types of polypeptides in an environmentally benign manner. Various ester derivatives of amino acids can be polymerized using proteases. However, the polymerization of unnatural amino acid esters general...
Article
Front Cover: A series of polypeptides are synthesized via chemoenzymatic polymerization, which utilizes aminolysis reaction catalyzed by proteases, in a facile, readily scalable, eco-friendly, and atom-economical manner. The polypeptide materials inspired by natural proteins are reviewed in terms of their structures and functionality. The cover is...
Article
Full-text available
Polypeptides inspired by the natural functional and structural proteins present in living systems are promising materials for various fields in terms of their versatile functionality and physical properties. Designing and synthesizing mimetic sequences of specific peptide motifs in proteins are important for exploring the functionality of natural p...
Article
Full-text available
Polypeptides containing 2-aminoisobutyric acid (Aib) units as an unnatural amino acid residue were synthesized by papain-catalyzed chemoenzymatic polymerization of a tripeptide ethyl ester l-Ala-Aib-l-Ala-OEt in an aqueous medium. The Aib-containing polypeptide adopted an α-helix conformation in both the solid and solution phases, which was induced...
Article
Synthesis of a series of diblock copolymers consisting of POSS-containing random methacrylate copolymers and polystyrene (P(MAPOSS-r-methyl methacrylate)-b-polystyrene etc.) has been established by reversible addition–fragmentation chain-transfer (RAFT) polymerisation. The polymerisation of styrene as the second block was well controlled when POSS-...
Article
An appropriate modification technique for silk materials is needed to effectively improve their physical properties for specific applications. A telechelic-type polyalanine (T-polyA) was synthesized by papain-catalyzed polymerization as a novel reinforcing agent for silk materials. A silk fibroin obtained from Bombyx mori was homogeneously doped wi...
Article
Novel multiblock polypeptides with a structure similar to the unique sequence observed in spider silk proteins (spidroins) were synthesized via a two-step chemical synthesis method, that is, chemoenzymatic polymerization, using papain followed by postpolycondensation. Two types of polypeptide fragments were prepared by chemoenzymatic polymerization...
Article
Front Cover: Unique telechelic-type polypeptides were synthesized by the facile and environmentally benign enzymatic polymerization using a telechelic initiator. The telechelic polyalanine was found to assemble into long nanofibers by the antiparallel β-sheet structure whereas the conventional linear polyalanine showed a granule-like morphology. Fu...
Article
A diblock copolymer poly(3-hexylthiophene)-block-poly(dimethylsiloxane) (P3HT-b-PDMS) was synthesized as a donor material for organic photovoltaic devices. The regioregular poly(3-hexylthiophene) (P3HT) with a bromo-terminal was prepared via Grignard metathesis polymerization, and poly(dimethylsiloxane) (PDMS) with a silane terminal was obtained by...
Article
Full-text available
The synthesis of biobased poly(ether benzoxazole) (PEBO) derived from natural product vanillin was investigated. Poly(ether o-hydroxy amide) (PEHA) was used as a precursor of PEBO. PEBO was obtained by thermal treatment of PEHA based on the cyclodehydration. Synthesized PEBO was analyzed by Fourier transform infrared spectrometry (FTIR), differenti...
Article
Chemical modification of silk materials is a powerful method of tailoring the desired physical properties for possible application in various fields. In this work, we modified silk fibroin with poly(2,6-dimethyl-1,5-phenylene ether) (PPE) in order to imbue the silks with hydrophobicity so as to resist the absorption of humidity. This modification w...
Article
In order to construct unique polypeptide architectures, a novel telechelic-type initiator with two leucine ethyl ester units is designed for chemoenzymatic polymerization. Glycine or alanine ethyl ester is chemoenzymatically polymerized using papain in the presence of the initiator, and the propagation occurs at each leucine ethyl ester unit to pro...
Article
Bio‐based ferulic acid (FA), (E)‐3‐(4‐hydroxy‐3‐methoxyphenyl)prop‐2‐enoic acid was converted to 1,2‐disubstituted ethylenic monomer (FA1) via methyl esterification followed by silylation with tert‐butyldimethylsilyl chloride. Radical copolymerization of FA1 with styrene (St), methyl methacrylate (MMA), and 4‐acetoxy‐3‐methoxystyrene (FA2) prepared...
Article
Renewable resources-based homo- and copolyesters were prepared from novel vanillin-based Schiff base and bio-based cinnamic acid derivatives by transesterification. Chemical structures of the Schiff base and resulting polesters were confirmed by FT-IR, 1H- and 13C-NMR. Glass transition temperatures of polymers were determined by DSC and showed over...
Article
Full-text available
The chemoenzymatic polymerization of amino acid monomers by proteases involves a two-step reaction: the formation of a covalent acyl-intermediate complex between the protease and the carboxyl ester group of the monomer and the subsequent deacylation of the complex by aminolysis to form a peptide bond. Although the initiation with the ester group of...
Article
Polycyanurates from 2,4-dichloro-6-methoxy-1,3,5-triazine with bisphenol A or 9,9-bis(4-hydroxyphenyl)fluorene were subjected to thermal treatment under argon to induce the thermal rearrangement of the polycyanurates into the corresponding polyisocyanurates. Thermally rearranged polymers with a wide range of conversions were prepared by simply chan...
Article
Full-text available
Polymer Journal, official journal of the Society of Polymer Science, Japan publishes high quality papers in all areas of polymer and macromolecular research.
Article
Here we report the facile network formation of a methacrylate polymer containing polyhedral oligomeric silsesquioxane (POSS) in the side chain by a dynamic cage-scrambling reaction mediated by fluoride ion. With 1,4-bis(triethoxysilyl)benzene (BTSB) as a cross-linker in the presence of tetrabutylammonium fluoride (TBAF), a self-standing cross-linke...
Article
Polyisocyanurates have been successfully prepared by the thermal rearrangement of polycyanurates, which were obtained from 2,4-dichloro-6-methoxy-1,3,5-triazine and bisphenol monomers. The thermal rearrangement was carried out in the presence of a small amount of tetrabutylammonium bromide (TBAB) as a catalyst at 200 °C for 30 or 60 min in an argon...
Article
A novel reactive polymer containing cyanate groups in the side chain was prepared by free radical polymerization of a cyanate-containing monomer, 2-(4-cyanatophenyl)ethyl methacrylate (1). The monomer 1 and its polymer, poly[2-(4-cyanatophenyl)ethyl methacrylate] (PCPMA), were stable under the air for a long period. The copolymerization of 1 and me...
Article
Diacetylene derivative, 1,6-bis(3-nonyl-9-carbazolyl)-2,4-hexadiyne was designed and synthesized. Compared with nonsubstituted 1,6-di(N-carbazolyl)-2,4-hexadiyne, the solubility was drastically unproved, which allowed us the fabrication of a smooth crystalline thin film via a simple spin-coating process. The resulting film was easily polymerized by...
Article
The electronic structures, conformation, and orientation of cyclooctatetracontane were studied by ultraviolet photoelectron and metastable atom electron spectroscopy for ultrathin films prepared on cooled graphite (0001) surfaces. It was found that molecules in a long and thin rectangular form are laid flat with the long sides placed with edge-on o...
Article
Thin films of a tetraphenylporphyrin‐end‐functionalized polycyclohexane zinc complex (ZnTPP‐PCHE)/fullerene‐C60 (C60) end‐functionalized poly(4‐diphenylaminostyrene) (C60‐PDAS) were prepared to investigate their potential as a light‐harvesting system for polymer solar cells (PSCs). The microphase separation in the ZnTPP‐PCHE/C60‐PDAS blends had a s...
Article
Thin films composed of zinc tetraphenylporphyrin-end-functionalized polycyclohexane (ZnTPP-PCHE) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blends were prepared to investigate their potential as light-harvesting systems within polymer solar cells (PSCs). Both the microphase separation characteristics and the extent of π–π interactions in...
Article
The synthesis of tetraphenylporphyrin (H2TPP)-end-functionalized poly(p-phenylene) (H2TPP-PPP) as a leaf-green-colored soluble semiconducting polymer with a well-controlled and defined polymer chain structure was achieved for the first time. Chloromethyl-end-functionalized poly(1,3-cyclohexadiene) (CM-PCHD) was prepared by the living anionic polyme...
Article
Novel graft copolymers, PTPA-g-PEAs containing poly(triphenylamine) (PTPA) backbone and poly(ethyl acrylate) (PEA) branches were synthesized by the oxidative coupling polymerization of triarylamine monomers followed by grafting of ethyl acrylate via an atom transfer radical polymerization (ATRP). Photorefractive (PR) composites based on the graft c...
Article
A new bifunctional photorefractive active succinate (TPD-2DCVA) consisting of a tetraphenyldiaminobiphenyl (TPD) unit and 4-dicyanovinylaniline (DCVA) moieties was prepared, which forms stable molecular glass. The glass-transition temperatures (T-g's) of TPD-2DCVA-based composites were efficiently controlled by the doping of small amount of plastic...
Article
The compound fac-Ir(ppy)3 (fac, facial; ppy, 2-phenylpyridyl) end-functionalized poly(4-diphenylaminostyrene) (PDAS) was synthesized by adding fac-Ir(ppy)2(vppy) (vppy,2-(4-vinylphenyl)pyridyl) to poly(4-diphenylaminostyryl)lithium (PDASLi). In this reaction, fac-Ir(ppy)2(vppy) acts as a fac-Ir(ppy)3 single-monomer addition reagent for PDASLi. The...
Article
The oxidative polymerization of thiophene derivatives was carried out using palladium (II) acetate as a catalyst in combination with copper (II) acetate and trifluoroacetic acid under an oxygen atmosphere. The poly(3-hexylthiophene) (P3HT) obtained through palladium-catalyzed polymerization exhibited a richer head-to-head content than authentic P3H...
Article
Single-molecule study of phenylenevinylene oligomers revealed distinct spectral forms due to different conjugation lengths which are determined by torsional defects. Large spectral jumps between different spectral forms were ascribed to torsional flips of a single phenylene ring. These spectral changes reflect the dynamic nature of electron delocal...
Article
For the preparation of block copolymers containing polyfluorene (PF) and hole transporting segment, PF homopolymers with diphenylamine terminals were synthesized by Suzuki coupling polymerization. The terminals of PF were converted to polytriphenylamine (PTPA) block by C–N coupling polymerization to give PTPA-block-PF-block-PTPA (PF-PTPA) triblock...
Article
Blue-light-emitting block copolymers based on polyfluorene (PF) and poly(triphenylamine) (PTPA) were synthesized for polymeric electroluminescent (EL) materials. PF with diphenylamine terminals were prepared by the Suzuki coupling polymerization, and converted to PTPA-block-PF-block-PTPA triblock copolymers by C-N coupling polymerization. The block...
Article
Cyclic oligomers composed of triphenylamine backbone were conveniently prepared via palladium-catalyzed one-pot synthesis. The condition for the preparation was optimized to give the cyclic oligomers with large ring sizes in good yield up to 73.7%. The type of base for the reaction dramatically influenced the yield of cyclic oligomers, and potassiu...
Article
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Simple and efficient stereo-selective synthesis of exo-5-norbornene-2-carboxylic acid (NBCA) is reported. Preliminary studies on base promoted isomerization of methyl 5-norbornene-2-carboxylate (MNBC) revealed that rapid isomeriza-tion was accomplished with sodium tert-butoxide (tBuONa), and the exo-content at the equilibrium was ca. 60%. The hydro...