Pub Date : 2024-09-25DOI: 10.1038/s41428-024-00963-0
Hiroya Shiba, Akikazu Matsumoto, Chie Kojima
Stimuli-sensitive polymers are useful smart materials. Dendrimers are synthetic polymers with well-defined structures, and various functional dendrimers have been produced by modifying compounds at their termini. We previously reported that polyamidoamine (PAMAM) dendrimers modified with cis-1,2-cyclohexane dicarboxylic acid (CHex) and phenylalanine (Phe), named PAMAM-CHex-Phe, exhibit upper critical solution temperature (UCST)-type thermosensitivity at acidic pH. In this study, we synthesized PAMAM dendrimers with CHex and various numbers of bound Phe residues and examined their pH and temperature sensitivities. Interestingly, PAMAM-CHex-Phe, with fewer than 32 Phe residues, showed lower critical solution temperature (LCST)-type thermosensitivity at pH 5 but not UCST-type thermosensitivity. PAMAM-CHex-Phe40 and PAMAM-CHex-Phe48 exhibited both LCST- and UCST-type thermosensitivity at pH values of 5 and 6, respectively. Fully Phe-modified PAMAM-CHex-Phe (PAMAM-CHex-Phe64) showed UCST-type but not LCST-type thermosensitivity. pH titration experiments suggested that the protonation behaviors of these dendrimers were different, likely resulting in different phase transitions. Therefore, the phase transition temperature and behavior could be regulated by varying the number of bound Phe residues in the PAMAM-CHex-Phe dendrimers and the solution pH. Polyamidoamine dendrimers modified with cis-1,2-cyclohexane dicarboxylic acid and phenylalanine, named PAMAM-CHex-Phe, with various numbers of Phe residues were synthesized as dual pH- and temperature-sensitive polymers. PAMAM-CHex-Phe, with fewer than 32 Phe residues, showed lower critical solution temperature (LCST)-type thermosensitivity at pH 5. PAMAM-CHex-Phe40 and PAMAM-CHex-Phe48 exhibited both LCST- and upper critical solution temperature (UCST)-type thermosensitivity at pH values of 5 and 6, respectively. PAMAM-CHex-Phe64 showed UCST-type thermosensitivity. Our results indicate that thermosensitivity can be regulated by changing the number of Phe residues in PAMAM-CHex-Phe and the solution pH.
{"title":"LCST/UCST-type thermosensitive properties of carboxy-terminal PAMAM dendrimers modified with different numbers of phenylalanine residues","authors":"Hiroya Shiba, Akikazu Matsumoto, Chie Kojima","doi":"10.1038/s41428-024-00963-0","DOIUrl":"10.1038/s41428-024-00963-0","url":null,"abstract":"Stimuli-sensitive polymers are useful smart materials. Dendrimers are synthetic polymers with well-defined structures, and various functional dendrimers have been produced by modifying compounds at their termini. We previously reported that polyamidoamine (PAMAM) dendrimers modified with cis-1,2-cyclohexane dicarboxylic acid (CHex) and phenylalanine (Phe), named PAMAM-CHex-Phe, exhibit upper critical solution temperature (UCST)-type thermosensitivity at acidic pH. In this study, we synthesized PAMAM dendrimers with CHex and various numbers of bound Phe residues and examined their pH and temperature sensitivities. Interestingly, PAMAM-CHex-Phe, with fewer than 32 Phe residues, showed lower critical solution temperature (LCST)-type thermosensitivity at pH 5 but not UCST-type thermosensitivity. PAMAM-CHex-Phe40 and PAMAM-CHex-Phe48 exhibited both LCST- and UCST-type thermosensitivity at pH values of 5 and 6, respectively. Fully Phe-modified PAMAM-CHex-Phe (PAMAM-CHex-Phe64) showed UCST-type but not LCST-type thermosensitivity. pH titration experiments suggested that the protonation behaviors of these dendrimers were different, likely resulting in different phase transitions. Therefore, the phase transition temperature and behavior could be regulated by varying the number of bound Phe residues in the PAMAM-CHex-Phe dendrimers and the solution pH. Polyamidoamine dendrimers modified with cis-1,2-cyclohexane dicarboxylic acid and phenylalanine, named PAMAM-CHex-Phe, with various numbers of Phe residues were synthesized as dual pH- and temperature-sensitive polymers. PAMAM-CHex-Phe, with fewer than 32 Phe residues, showed lower critical solution temperature (LCST)-type thermosensitivity at pH 5. PAMAM-CHex-Phe40 and PAMAM-CHex-Phe48 exhibited both LCST- and upper critical solution temperature (UCST)-type thermosensitivity at pH values of 5 and 6, respectively. PAMAM-CHex-Phe64 showed UCST-type thermosensitivity. Our results indicate that thermosensitivity can be regulated by changing the number of Phe residues in PAMAM-CHex-Phe and the solution pH.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 1","pages":"137-142"},"PeriodicalIF":2.3,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142925792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1038/s41428-024-00956-z
Jiaxin Zhao, Hongliang Hu, Dawei Jiang, Yujie Jin, Chun Li, Feng Luo
Wollastonite (W)/carbon black (CB)/chlorinated polyethylene (CPE) conductive composites were prepared via melt compounding using CB and wollastonite as fillers and CPE as the matrix. To analyze the internal structure of the material and examine how changes in crystallinity affect the positive temperature coefficient (PTC) behavior of the composites, several characterization techniques were employed. These methods included scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry. Each method provided insights into the structural adjustments and their implications for the electrical properties of the material. Special attention was given to the influence of the wollastonite content on the electrical conductivity of the composites. The results demonstrated that the lowest room-temperature resistivity (1.66 Ω·cm) was achieved with 15 wt.% wollastonite doping after 1 h of heat treatment. At the same time, the PTC strength increased to 4.7. Wollastonite (W)/carbon black (CB)/chlorinated polyethylene (CPE) conductive composites were prepared via melt compounding using CB and wollastonite as fillers and CPE as the matrix. The results indicated that the room temperature resistivity of CPE/CB/wollastonite composites decreased to 1.66Ω·cm after 1 hour of heat treatment, and the PTC strength reached 4.7. Subsequently, the relationship between the internal structure of the materials, changes in crystallinity, and PTC properties was analyzed using X-ray diffractometry and DSC differential scanning calorimetry.
{"title":"Effect of heat treatment time on the PTC behavior of wollastonite/CB/CPE composites","authors":"Jiaxin Zhao, Hongliang Hu, Dawei Jiang, Yujie Jin, Chun Li, Feng Luo","doi":"10.1038/s41428-024-00956-z","DOIUrl":"10.1038/s41428-024-00956-z","url":null,"abstract":"Wollastonite (W)/carbon black (CB)/chlorinated polyethylene (CPE) conductive composites were prepared via melt compounding using CB and wollastonite as fillers and CPE as the matrix. To analyze the internal structure of the material and examine how changes in crystallinity affect the positive temperature coefficient (PTC) behavior of the composites, several characterization techniques were employed. These methods included scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry. Each method provided insights into the structural adjustments and their implications for the electrical properties of the material. Special attention was given to the influence of the wollastonite content on the electrical conductivity of the composites. The results demonstrated that the lowest room-temperature resistivity (1.66 Ω·cm) was achieved with 15 wt.% wollastonite doping after 1 h of heat treatment. At the same time, the PTC strength increased to 4.7. Wollastonite (W)/carbon black (CB)/chlorinated polyethylene (CPE) conductive composites were prepared via melt compounding using CB and wollastonite as fillers and CPE as the matrix. The results indicated that the room temperature resistivity of CPE/CB/wollastonite composites decreased to 1.66Ω·cm after 1 hour of heat treatment, and the PTC strength reached 4.7. Subsequently, the relationship between the internal structure of the materials, changes in crystallinity, and PTC properties was analyzed using X-ray diffractometry and DSC differential scanning calorimetry.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 1","pages":"109-117"},"PeriodicalIF":2.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Photodynamic therapy is useful due to its high antitumor efficacy, spatiotemporal selectivity, and noninvasiveness and has garnered significant attention in the field of cancer treatment. When photoexcited by light irradiation, photosensitizers produce reactive oxygen species (ROS) that damage tumor tissues. However, photosensitizers can also accumulate in normal tissues, leading to side effects such as skin photosensitivity. To mitigate these side effects, we report the development of chlorophyll‒peptide conjugates as tumor-selective photosensitizers. These conjugates bearing histidine and lysine residues self-assemble into nanoparticles that are expected to accumulate selectively in tumors and reduce ROS generation through self-quenching under the neutral conditions typical of normal tissues. In contrast, these aggregated conjugates partially disassemble under weakly acidic conditions, such as those found in tumor tissues, resulting in phototoxicity. We anticipate that these acid-activatable conjugates have the potential to serve as cancer-selective photosensitizers, thereby reducing phototoxicity in normal tissues. Photodynamic therapy using photosensitizers as therapeutic agents has various advantages such as high antitumor efficacy, spatiotemporal selectivity, and noninvasiveness. However, photosensitizers also accumulate in normal tissues as well as tumor tissues, causing side effects. Here, we report chlorophyll‒peptide conjugates as novel photosensitizers to decrease the side effect. The assembled conjugates are expected to exhibit tumor-selective accumulation and tumor-selective activation of phototoxicity.
{"title":"Acid-activatable photosensitizers for photodynamic therapy using self-aggregates of chlorophyll‒peptide conjugates","authors":"Miyu Nagatani, Masaru Yoshikawa, Shinya Tsukiji, Masahiro Higuchi, Hitoshi Tamiaki, Shogo Matsubara","doi":"10.1038/s41428-024-00961-2","DOIUrl":"10.1038/s41428-024-00961-2","url":null,"abstract":"Photodynamic therapy is useful due to its high antitumor efficacy, spatiotemporal selectivity, and noninvasiveness and has garnered significant attention in the field of cancer treatment. When photoexcited by light irradiation, photosensitizers produce reactive oxygen species (ROS) that damage tumor tissues. However, photosensitizers can also accumulate in normal tissues, leading to side effects such as skin photosensitivity. To mitigate these side effects, we report the development of chlorophyll‒peptide conjugates as tumor-selective photosensitizers. These conjugates bearing histidine and lysine residues self-assemble into nanoparticles that are expected to accumulate selectively in tumors and reduce ROS generation through self-quenching under the neutral conditions typical of normal tissues. In contrast, these aggregated conjugates partially disassemble under weakly acidic conditions, such as those found in tumor tissues, resulting in phototoxicity. We anticipate that these acid-activatable conjugates have the potential to serve as cancer-selective photosensitizers, thereby reducing phototoxicity in normal tissues. Photodynamic therapy using photosensitizers as therapeutic agents has various advantages such as high antitumor efficacy, spatiotemporal selectivity, and noninvasiveness. However, photosensitizers also accumulate in normal tissues as well as tumor tissues, causing side effects. Here, we report chlorophyll‒peptide conjugates as novel photosensitizers to decrease the side effect. The assembled conjugates are expected to exhibit tumor-selective accumulation and tumor-selective activation of phototoxicity.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 1","pages":"119-128"},"PeriodicalIF":2.3,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00961-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1038/s41428-024-00965-y
Shinji Tanaka
Solid-state NMR is one of the most powerful analytical methods for the structural characterization and dynamics of polymers. Owing to its intrinsically low signal sensitivity, however, analysis of trace chemical species supported on polymers remains challenging. Solid-state NMR with dynamic nuclear polarization (DNP-NMR) has recently attracted attention as a highly sensitive NMR measurement method for analyzing polymers. We recently investigated DNP-NMR for insoluble polymers, particularly cross-linked polymers, engineering plastics, and polymer-supported catalysts, and achieved high NMR signal sensitivity at a routinely accessible level. In this focus review, we present case studies on DNP-NMR measurements for a wide range of polymers. Solid-state NMR with dynamic nuclear polarization (DNP-NMR) has recently attracted attention as a highly sensitive NMR measurement method for analyzing polymers. We recently investigated DNP-NMR for insoluble polymers, particularly cross-linked polymers, engineering plastics, and polymer-supported catalysts, and achieved high NMR signal sensitivity at a routinely accessible level. In this focus review, we present case studies on DNP-NMR measurements for a wide range of polymers.
{"title":"Structural analysis of polymers via solid-state dynamic nuclear polarization (DNP)-NMR","authors":"Shinji Tanaka","doi":"10.1038/s41428-024-00965-y","DOIUrl":"10.1038/s41428-024-00965-y","url":null,"abstract":"Solid-state NMR is one of the most powerful analytical methods for the structural characterization and dynamics of polymers. Owing to its intrinsically low signal sensitivity, however, analysis of trace chemical species supported on polymers remains challenging. Solid-state NMR with dynamic nuclear polarization (DNP-NMR) has recently attracted attention as a highly sensitive NMR measurement method for analyzing polymers. We recently investigated DNP-NMR for insoluble polymers, particularly cross-linked polymers, engineering plastics, and polymer-supported catalysts, and achieved high NMR signal sensitivity at a routinely accessible level. In this focus review, we present case studies on DNP-NMR measurements for a wide range of polymers. Solid-state NMR with dynamic nuclear polarization (DNP-NMR) has recently attracted attention as a highly sensitive NMR measurement method for analyzing polymers. We recently investigated DNP-NMR for insoluble polymers, particularly cross-linked polymers, engineering plastics, and polymer-supported catalysts, and achieved high NMR signal sensitivity at a routinely accessible level. In this focus review, we present case studies on DNP-NMR measurements for a wide range of polymers.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"57 1","pages":"25-32"},"PeriodicalIF":2.3,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research showed that the self-healing properties of reversible crosslinked gels with host–guest inclusion complexes depended on the mobility of network chains and the recombination behaviors of reversible complexes, which were affected by changes in the water–glycerol solvent composition. The sticky reptation behaviors of the polymer chains were delayed by the recombination behaviors of reversible bonds. These behavioral characteristics were observed based on a dynamic viscoelasticity. Increasing the glycerol concentration in the mixed solvent decreased the surface tension and increased the mobility of the network chains because the recombination of the complex was slowed by the weak hydrophobic interactions between the host and guest molecules. Consequently, self-healing properties, such as re-adhesion at the cutting surface, were improved by the interdiffusion of polymer chains at the reattached interface. The strong hydrophobic interactions in pure water promoted the formation of complexes within the same cutting surface, thus decreasing the self-healing rates of the mechanical properties. In this study, the solvent was found to be an important parameter for controlling the self-healing properties of reversible crosslinked gels. The competition between the mobility of polymer chains and the recombination behaviors of reversible bonds controlled the self-healing properties of the gels with host–guest inclusion complexes. This study examined how changing the water-glycerol solvent composition affects the self-healing and viscoelastic properties of self-healing gels, which have host-guest inclusion complexes as reversible crosslinks. Increasing glycerol concentration in the mixture solvent reduced hydrophobic interactions between β-cyclodextrin and adamantane, lowering the association constant of host-guest inclusion complexes. The weakened hydrophobic interaction hinders complex recombination and enhances the mobility of the network chains. Consequently, the enhancement of mobility improved the healing ratio because the interfacial diffusion of the chains was promoted at the repair interfaces.
{"title":"Viscoelastic behaviors for optimizing self-healing of gels with host–guest inclusion complexes","authors":"Kenji Yamaoka, Ryohei Ikura, Motofumi Osaki, Hidenori Shirakawa, Kazuya Takahashi, Hiroaki Takahashi, Yasumasa Ohashi, Yoshinori Takashima","doi":"10.1038/s41428-024-00932-7","DOIUrl":"10.1038/s41428-024-00932-7","url":null,"abstract":"This research showed that the self-healing properties of reversible crosslinked gels with host–guest inclusion complexes depended on the mobility of network chains and the recombination behaviors of reversible complexes, which were affected by changes in the water–glycerol solvent composition. The sticky reptation behaviors of the polymer chains were delayed by the recombination behaviors of reversible bonds. These behavioral characteristics were observed based on a dynamic viscoelasticity. Increasing the glycerol concentration in the mixed solvent decreased the surface tension and increased the mobility of the network chains because the recombination of the complex was slowed by the weak hydrophobic interactions between the host and guest molecules. Consequently, self-healing properties, such as re-adhesion at the cutting surface, were improved by the interdiffusion of polymer chains at the reattached interface. The strong hydrophobic interactions in pure water promoted the formation of complexes within the same cutting surface, thus decreasing the self-healing rates of the mechanical properties. In this study, the solvent was found to be an important parameter for controlling the self-healing properties of reversible crosslinked gels. The competition between the mobility of polymer chains and the recombination behaviors of reversible bonds controlled the self-healing properties of the gels with host–guest inclusion complexes. This study examined how changing the water-glycerol solvent composition affects the self-healing and viscoelastic properties of self-healing gels, which have host-guest inclusion complexes as reversible crosslinks. Increasing glycerol concentration in the mixture solvent reduced hydrophobic interactions between β-cyclodextrin and adamantane, lowering the association constant of host-guest inclusion complexes. The weakened hydrophobic interaction hinders complex recombination and enhances the mobility of the network chains. Consequently, the enhancement of mobility improved the healing ratio because the interfacial diffusion of the chains was promoted at the repair interfaces.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"56 11","pages":"1031-1039"},"PeriodicalIF":2.3,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00932-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10DOI: 10.1038/s41428-024-00958-x
Tomoyuki Kurioka, Ikuyoshi Tomita, Shinsuke Inagi
Fluorene (Fl) derivatives are representative emitting motifs; thus, they are often installed into alternating π-conjugated copolymers (P(Fl-Ar)) as soluble polymeric emitters. Many researchers have focused on modifying the combined arylene units in P(Fl-Ar) derivatives to tune their optoelectronic properties; however, P(Fl-Ar) derivatives that contain fluorene units with functional groups at their sp2 carbons remain limited. Here, we synthesize P(Fl-Ar) derivatives comprising sp2-chlorinated fluorene units via anodic chlorination using aluminum chloride (AlCl3). The introduced chlorine atoms affect the optoelectronic properties of the pristine P(Fl-Ar) derivatives. Compared with the precursor P(Fl-Ar) derivatives, chlorinated P(Fl-Ar) derivatives exhibit longer maximum emission wavelengths. Alternating π-conjugated copolymers containing 9,9-dialkylfluorene (Fl) units have been widely studied, but there are few of these copolymers with sp2-carbon functionalized Fl units. In this study, we expand this limitation by performing the anodic chlorination of alternating π-conjugated copolymers, which are composed of Fl and another arylene (Ar) (P(Fl-Ar)s), using an acetonitrile solution that contains aluminum chloride as an electrolyte. The sp2-carbon at the fluorene ring was successfully chlorinated by anodic chlorination. P(Fl-Ar)s containing sp2-chlorinated fluorene units has different emission properties from the original P(Fl-Ar)s.
{"title":"Post-functionalization of alternating π-conjugated copolymers containing fluorene moieties via anodic chlorination using AlCl3","authors":"Tomoyuki Kurioka, Ikuyoshi Tomita, Shinsuke Inagi","doi":"10.1038/s41428-024-00958-x","DOIUrl":"10.1038/s41428-024-00958-x","url":null,"abstract":"Fluorene (Fl) derivatives are representative emitting motifs; thus, they are often installed into alternating π-conjugated copolymers (P(Fl-Ar)) as soluble polymeric emitters. Many researchers have focused on modifying the combined arylene units in P(Fl-Ar) derivatives to tune their optoelectronic properties; however, P(Fl-Ar) derivatives that contain fluorene units with functional groups at their sp2 carbons remain limited. Here, we synthesize P(Fl-Ar) derivatives comprising sp2-chlorinated fluorene units via anodic chlorination using aluminum chloride (AlCl3). The introduced chlorine atoms affect the optoelectronic properties of the pristine P(Fl-Ar) derivatives. Compared with the precursor P(Fl-Ar) derivatives, chlorinated P(Fl-Ar) derivatives exhibit longer maximum emission wavelengths. Alternating π-conjugated copolymers containing 9,9-dialkylfluorene (Fl) units have been widely studied, but there are few of these copolymers with sp2-carbon functionalized Fl units. In this study, we expand this limitation by performing the anodic chlorination of alternating π-conjugated copolymers, which are composed of Fl and another arylene (Ar) (P(Fl-Ar)s), using an acetonitrile solution that contains aluminum chloride as an electrolyte. The sp2-carbon at the fluorene ring was successfully chlorinated by anodic chlorination. P(Fl-Ar)s containing sp2-chlorinated fluorene units has different emission properties from the original P(Fl-Ar)s.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"56 12","pages":"1117-1127"},"PeriodicalIF":2.3,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00958-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We fabricated a volatile organic compound (VOC) sensor with a peptide–Au nanoparticle (AuNP)–TiO2 nanocomposite in which AuNPs were linked with TiO2-coated conductive peptide nanowires. The conductive peptide nanowires were formed between the AuNPs via self-assembly through the complexation of amphiphilic peptides, LESEHEKLKSKHKSKLKEHESEL, and Co(II). Furthermore, TiO2 mineralization on the surface of the peptide nanowires yielded mixed crystals of rutile and anatase, which exhibited highly effective photolytic activity. In particular, the obtained TiO2 exhibited three times greater photodecomposition activity in the unsintered state toward organic matter than did commercially available TiO2. Next, we constructed a VOC sensor by immobilizing peptide–AuNP–TiO2 nanocomposites on a comb electrode. The electrochemical properties of the nanocomposite changed drastically under light irradiation in the presence of VOCs, indicating transport of the VOC-decomposition-generated photoexcited electrons of TiO2 to AuNPs through conductive peptide nanowires, which prevented electron–hole recombination. The obtained sensor exhibited a sensing range of 2–100 ppm for dichloromethane, which was used as a representative VOC. Therefore, nanocomposites made of AuNPs linked with conductive TiO2 nanotubes may be highly effective for TiO2-driven VOC decomposition. Moreover, we believe that this nanocomposite has high sensitivity for sensing VOCs. The peptide-Au nanoparticle (AuNP)-TiO2 nanocomposite in which AuNPs were connected by TiO2-coated conductive peptide nanowire was acted as effective VOC sensor.
{"title":"Fabrication of a peptide–AuNP–TiO2 nanocomposite and its application as a VOC sensor","authors":"Toma Iwakiri, Hikari Suzuki, Shogo Mastubara, Masahiro Higuchi","doi":"10.1038/s41428-024-00960-3","DOIUrl":"10.1038/s41428-024-00960-3","url":null,"abstract":"We fabricated a volatile organic compound (VOC) sensor with a peptide–Au nanoparticle (AuNP)–TiO2 nanocomposite in which AuNPs were linked with TiO2-coated conductive peptide nanowires. The conductive peptide nanowires were formed between the AuNPs via self-assembly through the complexation of amphiphilic peptides, LESEHEKLKSKHKSKLKEHESEL, and Co(II). Furthermore, TiO2 mineralization on the surface of the peptide nanowires yielded mixed crystals of rutile and anatase, which exhibited highly effective photolytic activity. In particular, the obtained TiO2 exhibited three times greater photodecomposition activity in the unsintered state toward organic matter than did commercially available TiO2. Next, we constructed a VOC sensor by immobilizing peptide–AuNP–TiO2 nanocomposites on a comb electrode. The electrochemical properties of the nanocomposite changed drastically under light irradiation in the presence of VOCs, indicating transport of the VOC-decomposition-generated photoexcited electrons of TiO2 to AuNPs through conductive peptide nanowires, which prevented electron–hole recombination. The obtained sensor exhibited a sensing range of 2–100 ppm for dichloromethane, which was used as a representative VOC. Therefore, nanocomposites made of AuNPs linked with conductive TiO2 nanotubes may be highly effective for TiO2-driven VOC decomposition. Moreover, we believe that this nanocomposite has high sensitivity for sensing VOCs. The peptide-Au nanoparticle (AuNP)-TiO2 nanocomposite in which AuNPs were connected by TiO2-coated conductive peptide nanowire was acted as effective VOC sensor.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"56 12","pages":"1211-1221"},"PeriodicalIF":2.3,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00960-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-05DOI: 10.1038/s41428-024-00951-4
Keiichi Imato, Yousuke Ooyama
Functional dyes exhibit intriguing properties in response to external stimuli related to their optical, electronic, structural, and energetic characteristics and enable unique stimuli-responsive functions in materials by collaborating with polymers, particularly when chemically incorporated into the polymer structures. As well as the structures and properties of functional dyes, polymers, assemblies, and materials, the interactions between these components are important to the functions of materials. In this review, we introduce our recent studies conducted in the past half decade on stimuli-responsive smart polymers and polymeric materials based on functional dyes that are chemically incorporated into the polymer structures, with a special focus on light, force, electric fields, and chemicals including water in a variety of external stimuli. For example, these polymers and materials offer switchable adhesion, mechanical actuation, and chemical sensing. Functional dyes offer fascinating properties in response to external stimuli and enable unique stimuli-responsive functions in materials by chemical incorporation into polymers. In this review, we highlight our recent studies conducted in the last half decade on stimuli-responsive smart polymers and polymeric materials offering, for example, switchable adhesion, mechanical actuation, and chemical sensing based on functional dyes that are chemically incorporated into the structures, with a particular focus on the stimuli of light, force, electric fields, and chemicals including water.
{"title":"Stimuli-responsive smart polymers based on functional dyes","authors":"Keiichi Imato, Yousuke Ooyama","doi":"10.1038/s41428-024-00951-4","DOIUrl":"10.1038/s41428-024-00951-4","url":null,"abstract":"Functional dyes exhibit intriguing properties in response to external stimuli related to their optical, electronic, structural, and energetic characteristics and enable unique stimuli-responsive functions in materials by collaborating with polymers, particularly when chemically incorporated into the polymer structures. As well as the structures and properties of functional dyes, polymers, assemblies, and materials, the interactions between these components are important to the functions of materials. In this review, we introduce our recent studies conducted in the past half decade on stimuli-responsive smart polymers and polymeric materials based on functional dyes that are chemically incorporated into the polymer structures, with a special focus on light, force, electric fields, and chemicals including water in a variety of external stimuli. For example, these polymers and materials offer switchable adhesion, mechanical actuation, and chemical sensing. Functional dyes offer fascinating properties in response to external stimuli and enable unique stimuli-responsive functions in materials by chemical incorporation into polymers. In this review, we highlight our recent studies conducted in the last half decade on stimuli-responsive smart polymers and polymeric materials offering, for example, switchable adhesion, mechanical actuation, and chemical sensing based on functional dyes that are chemically incorporated into the structures, with a particular focus on the stimuli of light, force, electric fields, and chemicals including water.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"56 12","pages":"1093-1109"},"PeriodicalIF":2.3,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41428-024-00951-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of bioactive scaffolds is essential for tissue engineering because of the influence of material physicochemical properties on cellular activities. Recently, we discovered that percolation-induced 4-arm polyethylene glycol (PEG) hydrogels achieved gel–gel phase separation (GGPS), which has tissue affinity in vivo. However, whether the 4-arm structure is the optimal configuration for the use of PEG hydrogels as scaffolds remains unclear. In this study, we investigated the effect of an increased branching factor on GGPS. Compared with the 4-arm PEG hydrogel, the 8-arm PEG hydrogel presented a greater degree of GGPS and increased hydrophobicity. We introduced the RGD sequence into PEG hydrogels to directly assess the biological activity of GGPS, with a particular focus on its effects on the activity of bone-forming osteoblasts. Although the 8-arm PEG hydrogel did not enhance cell adhesion, it enhanced osteoblast differentiation compared with the 4-arm PEG hydrogel. Therefore, the 8-arm PEG hydrogel mediated by GGPS shows promise as a scaffold for osteoblast differentiation and holds potential as a foundation for future advancements in bone tissue engineering.
{"title":"Osteogenic differentiation capabilities of multiarm PEG hydrogels: involvement of gel–gel-phase separation in cell differentiation","authors":"Jinyan Si, Shohei Ishikawa, Shant Nepal, Hiroyuki Okada, Ung-il Chung, Takamasa Sakai, Hironori Hojo","doi":"10.1038/s41428-024-00955-0","DOIUrl":"https://doi.org/10.1038/s41428-024-00955-0","url":null,"abstract":"<p>The development of bioactive scaffolds is essential for tissue engineering because of the influence of material physicochemical properties on cellular activities. Recently, we discovered that percolation-induced 4-arm polyethylene glycol (PEG) hydrogels achieved gel–gel phase separation (GGPS), which has tissue affinity in vivo. However, whether the 4-arm structure is the optimal configuration for the use of PEG hydrogels as scaffolds remains unclear. In this study, we investigated the effect of an increased branching factor on GGPS. Compared with the 4-arm PEG hydrogel, the 8-arm PEG hydrogel presented a greater degree of GGPS and increased hydrophobicity. We introduced the RGD sequence into PEG hydrogels to directly assess the biological activity of GGPS, with a particular focus on its effects on the activity of bone-forming osteoblasts. Although the 8-arm PEG hydrogel did not enhance cell adhesion, it enhanced osteoblast differentiation compared with the 4-arm PEG hydrogel. Therefore, the 8-arm PEG hydrogel mediated by GGPS shows promise as a scaffold for osteoblast differentiation and holds potential as a foundation for future advancements in bone tissue engineering.</p>","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"59 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-03DOI: 10.1038/s41428-024-00957-y
Yalei Liu, Junfang Chang, Zhiyong Guo, Sui Wang, Jie Mao
Multifunctional hydrogel materials are being increasingly used in wearable sensing devices and biomedical applications, but the comprehensive performance of hydrogel materials must be further developed. To prepare hydrogels with better self-healing properties, biomacromolecules such as sodium alginate and carboxymethyl chitosan were used as raw materials by combining the dynamic imine bonding network formed by both materials with the coordination bonding network formed by acrylic acid and aluminum ions. The double network structure of the hydrogel provides the hydrogel with excellent self-healing properties (up to 127% recovery of toughness after self-healing) and good mechanical properties with a fracture strain of 3787%. Substances with antimicrobial properties in the hydrogel network inhibited the growth of E. coli and S. aureus. In addition, the hydrogel has good electrical conductivity with a conductivity of 1.41 S/m. This study examined multiple properties of the hydrogel and provides a reference for the application of this material in practical application scenarios. Sodium alginate and carboxymethyl chitosan were used as raw materials, and the dynamic imine bonding network formed by the two was combined with the coordination bonding network formed by acrylic acid and aluminum ions. The dual-network structure of the hydrogel not only gives the hydrogel excellent self-healing properties, but also gives the hydrogel excellent mechanical properties, with a strain at break as high as 3787%. In addition, the hydrogel has the antibacterial property of inhibiting the growth of E. coli and S. aureus and good electrical conductivity.
{"title":"High-strength, conductive, double-network self-healing antibacterial hydrogel based on the coordination bond and dynamic imine bond","authors":"Yalei Liu, Junfang Chang, Zhiyong Guo, Sui Wang, Jie Mao","doi":"10.1038/s41428-024-00957-y","DOIUrl":"10.1038/s41428-024-00957-y","url":null,"abstract":"Multifunctional hydrogel materials are being increasingly used in wearable sensing devices and biomedical applications, but the comprehensive performance of hydrogel materials must be further developed. To prepare hydrogels with better self-healing properties, biomacromolecules such as sodium alginate and carboxymethyl chitosan were used as raw materials by combining the dynamic imine bonding network formed by both materials with the coordination bonding network formed by acrylic acid and aluminum ions. The double network structure of the hydrogel provides the hydrogel with excellent self-healing properties (up to 127% recovery of toughness after self-healing) and good mechanical properties with a fracture strain of 3787%. Substances with antimicrobial properties in the hydrogel network inhibited the growth of E. coli and S. aureus. In addition, the hydrogel has good electrical conductivity with a conductivity of 1.41 S/m. This study examined multiple properties of the hydrogel and provides a reference for the application of this material in practical application scenarios. Sodium alginate and carboxymethyl chitosan were used as raw materials, and the dynamic imine bonding network formed by the two was combined with the coordination bonding network formed by acrylic acid and aluminum ions. The dual-network structure of the hydrogel not only gives the hydrogel excellent self-healing properties, but also gives the hydrogel excellent mechanical properties, with a strain at break as high as 3787%. In addition, the hydrogel has the antibacterial property of inhibiting the growth of E. coli and S. aureus and good electrical conductivity.","PeriodicalId":20302,"journal":{"name":"Polymer Journal","volume":"56 12","pages":"1197-1209"},"PeriodicalIF":2.3,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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