Polymer Journal

Nishikawa, Tsuyoshi

doi: 10.1038/s41428-024-00935-4pmid: N/A

Vinyl polymers are typically synthesized through the addition polymerization of corresponding vinyl compounds. However, the polymerization ability significantly depends on the substituent on the vinyl moiety, resulting in various synthetic limitations in the molecular structure of vinyl polymers. Given the increasing societal demand for enhanced properties and functions of polymer materials, innovative synthetic technologies are required for developing next-generation polymers through flexible molecular design. The author has made considerable efforts to overcome these limitations in polymer synthesis by employing alkenyl boronates as monomers for radical polymerization. The resulting polymers bear boron on the main chain, allowing the replacement of boron side chains with other elements through the cleavage of carbon–boron bonds in postpolymerization transformations. This strategy, based on “side-chain replacement,” has enabled the synthesis of various polymers that were previously inaccessible.

Yamagishi, Hiroshi

doi: 10.1038/s41428-024-00925-6pmid: N/A

An optical microresonator is a micrometer-scale object that can confine light inside its body via total internal reflection at the boundary. In addition to well-established applications, including laser oscillators, optical sensors, and quantum memory, optical resonators have attracted renewed attention in chemistry and biology as minute and highly sensitive sensors that work in the environment and inside biological tissues and cells without any connected wires. Optical resonators should be functional for facilitating molecular interactions and biological compatibility, which is, however, challenging with conventional materials and processing techniques. In contrast, the authors have been tackling this issue by using supramolecular chemistry, which enables the assembly of optical resonators from chemically and biologically functional organic materials in solution. This article reviews our recent progress on the methodologies for making organic optical resonators and their emergent optical properties.

Nishiguchi, Akihiro

doi: 10.1038/s41428-024-00934-5pmid: N/A

Injectable hydrogels that can be administered via syringes have enormous potential as cell delivery carriers for cell transplantation therapy. Owing to their beneficial properties, including biocompatibility, biodegradability, tissue adhesion, and scaffold functions, injectable hydrogels can be used to improve the delivery efficacy and survival of transplanted cells posttransplantation. Moreover, delivery via injection does not require culture or invasive surgical procedures, leading to reduced costs, processing time, and patient burden. To develop injectable hydrogels for clinical translation, hydrogels have been functionalized using various biological and physicochemical engineering approaches to induce angiogenesis, suppress immune rejection, provide viscoelasticity, and allow pore formation for cell infiltration. This focus review discusses the design of optimal injectable hydrogels for cell delivery. Moreover, this focus review summarizes the different approaches available to improve the biological and physicochemical features of hydrogels, lists their impacts on cellular functions, and highlights their therapeutic efficacy.

Shibasaki, Kazuki; Hsu, Yu-I; Uyama, Hiroshi

doi: 10.1038/s41428-024-00918-5pmid: N/A

General-purpose petroleum-derived plastic remains in the environment for long periods and has significant impacts on oceans and land. Biodegradable and biomass plastics are being developed around the world as countermeasures. A poly(lactic acid) (PLA)/thermoplastic starch (TPS) blend is a promising ecofriendly alternative to biodegradable plastic made from plants. However, owing to the hydrophilicity of starch and the hydrophobicity of PLA, phase separation occurs between PLA and starch. Furthermore, PLA/TPS blends have poor water resistance because of the presence of starch, limiting their applications. In this study, to improve the affinity of PLA for starch, oligo(lactic acid)-grafted starch (OLAgSt) was synthesized as a compatibilizer for PLA/TPS blends, and the effect of its addition to PLA/TPS blends was evaluated. OLAgSt with different OLA molecular weights and degrees of substitution (DS) were synthesized, and their effects on PLA/TPS were compared. The results indicated that OLAgSt functioned as a good compatibilizer, improving the dispersibility of TPS in PLA with 4 wt% OLAgSt added to PLA/TPS and improving the water resistance. Moreover, the OLA molecular weight of OLAgSt was greater than that of DS. These results are expected to facilitate the development of PLA/TPS applications in the food packaging and biomedical fields.

Law, Simon Sau Yin; Kuzumoto, Mako; Fujita, Seiya; Fujigaya, Tsuyohiko; Numata, Keiji

doi: 10.1038/s41428-024-00927-4pmid: N/A

Functionalized carbon nanotubes have shown tremendous promise in the field of plant biotechnology for genetic engineering and cargo delivery; recent findings have shown that they can be delivered within specific organelles, such as mitochondria and chloroplasts, in intact plants. 2-Aminoisobutyric acid is an unnatural amino acid that promotes helical conformation and has been demonstrated to increase membrane permeability. Rational substitution of this amino acid into a mitochondrial targeting peptide induced a helical conformation that, when functionalized onto polymer-coated carbon nanotubes, conferred increased membrane permeability compared with that of the native peptide. The secondary structure was maintained on the surface and, when used to deliver pDNA, led to an increase in gene expression, suggesting that this method may be used to enhance the delivery efficiency of existing functional peptides.

Miyake, Junpei

doi: 10.1038/s41428-024-00933-6pmid: N/A

In this paper, the use of 2-picoline borane (pic-BH3) as a reducing agent for the reductive amination of chitosan is reported for the first time. By optimizing the feed molar ratio of chitosan, benzaldehyde and pic-BH3, a high yield of isolated N-benzyl chitosan with a nearly perfect degree of substitution is successfully obtained. This material has rarely been obtained with previous methods. The newly developed synthetic method herein has many advantages, including being more facile, more efficient, and less harmful than conventional methods; thus, this method is applicable to other aldehydes or ketones, leading to wide varieties of N-modified chitosan in the future.

Nagumo, Ryo; Shibata, Ayami; Taniguchi, Ikuo; Iwata, Shuichi

doi: 10.1038/s41428-024-00936-3pmid: N/A

The dynamic and structural properties of the water molecules in 3-(1-piperazinyl)-1,2-propanediol-containing polyvinyl alcohol membranes were analyzed by molecular dynamics simulations. The resulting curve of the coordination number with diffusivity yielded important insights into the changes in the state of the water molecules with the water content, clarifying a key factor in determining the membrane performance for CO2 separation.[graphic not available: see fulltext]

Kugo, Yuki; Isono, Takuya; Fujiwara, Masashi; Sato, Toshifumi; Tani, Hirofumi; Erata, Tomoki; Tajima, Kenji

doi: 10.1038/s41428-024-00928-3pmid: N/A

Cellulose II exhibits exceptional attributes, including flexibility, high stainability, and gloss. However, its strength is lower than that of cellulose I due to reduced crystallinity during the crystal transition. In this study, we devised a novel method to regulate the proportion and distribution of cellulose I and II crystals. This was achieved by employing a low-concentration alkaline solution and liquid nitrogen, resulting in a high-strength composite material that retained the excellent properties of cellulose II. When cellulose powder was immersed in an 8 wt% NaOH solution and quenched with liquid nitrogen, the crystal transition from cellulose I to II occurred outward from the sample periphery to its center. The percentage of cellulose II increased proportionally with treatment time. This technique was extended to cellulose I-rich cotton fibers, facilitating the creation of a composite fiber with cellulose I at the core and cellulose II on the surface. The tensile strength and Young’s modulus of the composite fiber were greater than those of the mercerized cellulose II fiber. Additionally, the elongation at break and toughness of these fibers surpassed those of conventional cotton fibers. This innovative method allows for the preparation of cellulose I and II composite materials with diverse properties.