Macroscopic Property Evaluation of Titania Nanocomposite Polymer Capable of Drawing Double-Network Macrostructure Using Photolithography.

In this study, we developed a double-network hybrid polymer that controls the strength and density of cross-linking points by utilizing the bonds of titania and catechol groups with an o-nitrobenzyl group (ONBg) as the photoreactive cross-linking points. In addition, this hybrid material system, which is composed of thermally dissociable bonds between titania and carboxyl groups, can be molded before light irradiation. The Young's modulus increased by approximately 1000 times upon irradiation with UV light. Moreover, introducing microstructures using the photolithography technique improved the tensile strength and fracture energy by approximately 32 and 15 times, respectively, compared to the sample without the photoreaction. The improved toughness was achieved by the macrostructures, which enhanced the effective cleavage of sacrificial bonds between the carboxyl groups and titania.

Long-term stability of over-the-counter cuffless blood pressure monitors: a proposal.

Blood pressure is an important cardiovascular parameter. Currently, the cuff-based sphygmomanometer is a popular, reliable, measurement method, but blood pressure monitors without cuffs have become popular and are now available without a prescription. Blood pressure monitors must be approved by regulatory authorities. Current cuffless blood pressure (CL-BP) monitors are not suitable for at-home management and prevention of hypertension. This paper proposes simple criteria for over-the-counter CL-BP monitoring. First, the history of the sphygmomanometer and current standard blood pressure protocol are reviewed. The main components of CL-BP monitoring are accuracy during the resting condition, accuracy during dynamic blood pressure changes, and long-term stability. In this proposal we recommend intermittent measurement to ensure that active measurement accuracy mirrors resting condition accuracy. A new experimental protocol is proposed to maintain long-term stability. A medically approved automated sphygmomanometer was used as the standard device in this study. The long-term accuracy of the test device is based on the definition of propagation error, i.e., for an oscillometric automated sphygmomanometer (5 ± 8 mmHg) ± the error for the test device static accuracy (-0.12 ± 5.49 mmHg for systolic blood pressure and - 1.17 ± 5.06 mmHg for diastolic blood pressure). Thus, the long-term stabilities were - 3.38 ± 7.1 mmHg and - 1.38 ± 5.4 mmHg, which satisfied propagation error. Further research and discussion are necessary to create standards for use by manufacturers; such standards should be readily evaluated and ensure high-quality evidence. Supplementary information: The online version contains supplementary material available at 10.1007/s12553-023-00726-6.

Skillful Control of Dispersion and 3D Network Structures: Advances in Functional Organic-Inorganic Nano-Hybrid Materials Prepared Using the Sol-Gel Method.

Organic-inorganic hybrid materials have become indispensable high-performance and highly functional materials. This is owing to the improved dispersion control in hybrid materials and emergence of functional ionic liquids. Harmonization of both these factors has enabled the utilization of functional 3D network structures and nanodispersions in composite materials. Polymeric materials endow materials with flexibility, toughness, and shape-memory properties, whereas inorganic materials provide materials with unique optical, electrical, and magnetic properties due to their nanosize. Organic-inorganic hybrid materials have evolved into novel materials that go beyond the composite rule. In this review, the historical development of hybrid materials prepared using the sol-gel method and the birth of ionic liquids have been summarized. In addition, the historical results leading to the development of functional 3D network structures and dispersion control have also been presented, as well as a review of the research on functional ionic liquids, which are of current interest. The authors also summarize the results of their research on functional ionic liquids. The design of new organic-inorganic hybrid materials has been discussed and the future prospects of new polymer composite materials provided.

Rapid removal of detergent in glycolipids using ionic liquids.

Detergent removal in glycolipid after sample preparation, such as enzymatic reaction or isolation of detergent-resistant membrane microdomain, is indispensable for further structural characterization. We previously established the rapid and effective method of detergent removal in glycolipid samples from glass test tube using 1,2-dichloroethane (DCE) washing. However, the use of DCE has several drawbacks, such as environmental risks, harmful effects (potentially carcinogenic), and high vaporability and flammability. To solve the issue, we used ionic liquids to remove detergents from glycolipid samples, and found 1-butyl-3-methylimidazolium iodide was a suitable alternative for DCE.

Polycarbonate/Titania Hybrid Films with Localized Photo-Induced Magnetic-Phase Transition.

Materials that exhibit the photo-induced magnetic-phase transition of titania are receiving significant attention because they can be easily switched between diamagnetism and paramagnetism by UV irradiation. However, it is difficult to store photo-induced titanium (Ti3+) in air because of its easy oxidation upon oxygen exposure. In this study, titania/polycarbonate hybrid films were prepared using linear 1,6-hexanediol (PHMCD), cyclic 1,4-cyclohexanedimethanol (PCHCD), or their copolymerized carbonate oligomers using the sol-gel method. The oxygen permeability of the hybrid film decreased as the ratio of the ring structure increased by a factor of approximately 32 from PHMCD with only the chain structure to PCHCD with only the ring structure. These hybrid films can generate Ti3+ under a UV irradiation of 250 W for 2 h, and the difference in oxygen permeability significantly affected the lifetime of the Ti3+ by a factor of up to 120. In addition, the tensile tests and IR measurements demonstrated that UV irradiation had little effect on the mechanical intensity and matrix chemical structure. Moreover, the magnetic susceptibility of Ti3+ present in PCHCD was confirmed to be 6.2 (10-3 emu/g(titania)) under an external magnetic field of 5 T induced using a superconducting quantum interference device.

One-pot synthesis of monodisperse CoFe2O4@Ag core-shell nanoparticles and their characterization.

In recent years, monodispersed magnetic nanoparticles with a core/shell structure are expected for their wide applications including magnetic fluid, recoverable catalysts, and biological analysis. However, their synthesis method needs numerous processes such as solvent substitution, exchange of protective agents, and centrifugation. A simple and rapid method for the synthesis of monodispersed core-shell nanoparticles makes it possible to accelerate their further applications. This paper describes a simple and rapid one-pot synthesis of core (CoFe2O4)-shell (Ag) nanoparticles with high monodispersity. The synthesized nanoparticles showed plasmonic light absorption owing to the Ag shell. Moreover, the magnetic property of the nanoparticles had a soft magnetic behavior at room temperature and a hard magnetic behavior at 5 K. In addition, the nanoparticles showed high monodispersity with a low polydispersity index (PDI) value of 0.083 in hexane.

Preparation of Crystallites for Oriented Poly(Lactic Acid) Films Using a Casting Method under a Magnetic Field.

Poly-l-lactic acid (PLLA) has biocompatibility and unique characteristics such as piezoelectric properties. This attracts attention not only in the environmental field but also in the biomedical and electronic materials fields. In recent years, the literature about orienting PLLA crystals has been promoting new applications for PLLA such as high strength fiberization and piezoelectric properties. This paper presents a new technique to orient the PLLA crystalline through casting under magnetic irradiation. The advantage of this technique is that it is possible to radiate the magnetic field to the PLLA crystalline in an extremely low viscosity environment. Moreover, the heat treatment condition was optimized in order to improve the low crystallinity of casting, and it succeeded in producing a PLLA film with a high degree of orientation and high crystallinity. Furthermore, PLLA/1-butyl-3-methylimidazolium dibutylphosphate (bmimjdbp) composite films were prepared under the same conditions, and this also succeeded in the further improvement of crystallinity.

Conformation of poly(γ-glutamic acid) in aqueous solution.

Local conformation and overall conformation of poly(γ-DL-glutamic acid) (PγDLGA) and poly(γ-L-glutamic acid) (PγLGA) in aqueous solution was studied as a function of degree of ionization ε by (1) H-NMR, circular dichroism, and potentiometric titration. It was clarified that their local conformation is represented by random coil over an entire ε range and their overall conformation is represented by expanded random-coil in a range of ε > ε(*) , where ε(*) is about 0.3, 0.35, 0.45, and 0.5 for added-salt concentration of 0.02M, 0.05M, 0.1M, and 0.2M, respectively. In a range of ε < ε(*) , however, ε dependence of their overall conformation is significantly differentiated from each other. PγDLGA tends to aggregate intramolecularly and/or intermolecularly with decreasing ε, but PγLGA still behaves as expanded random-coil. It is speculated that spatial arrangement of adjacent carboxyl groups along the backbone chain essentially affects the overall conformation of PγGA in acidic media.

Polypeptide aptamer selection using a stabilized ribosome display.

A newly developed ribosome display protocol was applied to the in vitro selection of polypeptide aptamers to small molecular weight chemicals, 6-[hydroxy(4-nitrobenzyl)phosphonyl]hexanoic acid and vitamin B12, chosen from a peptide library of random sequences. New peptide sequences binding to the targets were found after six rounds of this protocol.

Synthetic polymer-tissue adhesion using an ultrasonic scalpel.

BACKGROUND: Interface phenomena such as encapsulation and formation of dead space around implanted biomaterials lower biomaterial performance. To advance tissue adhesive technology, understanding the interactions between tissue (collagen) and polymer is indispensable. Adhesion between tissue and polymer was studied using an ultrasonically activated scalpel (UAS). METHODS: The Harmonic Scalpel was used as an ultrasonically activated scalpel for polymer and tissue adhesion. A piece of porcine aorta and a polymeric film were layered and placed between the blades of the Harmonic Scalpel. Then the samples were gripped with 20 kgf of force for 1-10 s to adhere the porcine aorta and polymeric films. The adhesion was characterized by macro- and microscopic observation, thermographic analysis, and measurement of bonding strength, static contact angle (SCA), and surface properties. RESULTS: Cellulose, vinylon, polyethylene terephthalate, nylon, and Pellethane could be bonded to the aorta. Bonding was not observed for the polyethylene, polypropylene, polyvinyl chloride, or polytetrafluoroethylene. This suggests that the existence of functional groups such as hydroxyl, carbonyl, carboxyl, and amide groups in the polymer structure are key factors in adhesion. Harmonic Scalpel modification of the polyethylene surface during corona discharge treatment further indicated that the functional groups of the polymers are one of the essential factors for tissue adhesion. The temperatures of adhesion were 90-150 °C for the polymers, and the melting temperatures (Tm) were 193-306 °C. This suggests that adhesion was formed by the interaction between the melted polymer surface and the tissue collagen. CONCLUSION: Both polar functional groups and adequate thermal characteristics are necessary for polymers to bond with tissues. These findings should be useful for the development of novel polymers that can be bonded to living tissues with UAS treatment, which can be applied for endoscopic surgery.

Visible light-induced crosslinkable gelatin.

A novel visible light-crosslinkable porcine gelatin was prepared for gelation and micropatterning. The preparation employed a photo-oxidation-induced crosslinking mechanism. First, furfuryl groups were incorporated into the gelatin. Second, the modified gelatin was mixed in water with Rose Bengal, which is a visible light sensitizer. Irradiation by visible light solidified the aqueous solution. In addition, when the solution was cast on a plate, dried and photo-irradiated in the presence of a photomask a micropattern was formed that matched the micropattern on the photomask. The gelatin-immobilized regions enhanced cell adhesion. It was also confirmed that the gelatin incorporating furfuryl and Rose Bengal have no significant toxicity. The photo-crosslinkable gelatin was employed as a direct pulp capping material in the dental field. Considering these results, this system could be useful as a new type of visible light-induced crosslinkable biosealant.

DNA templated nucleophilic aromatic substitution reactions for fluorogenic sensing of oligonucleotides.

We have developed an S(N)Ar reaction-triggered fluorescence probe using a new fluorogenic compound derivatized from 7-aminocoumarin for oligonucleotides detection.

Studies on the conformation of a polyelectrolyte in solution: local conformation of cucumber green mottle mosaic virus RNA compared with tobacco mosaic virus RNA.

The thermal stability of the local structures of cucumber green mottle mosaic virus RNA, CGMMV-RNA, and tobacco mosaic virus RNA, TMV-RNA, was studied by circular dichroism (CD) and small-angle X-ray scattering (SAXS) and compared with each other in the temperature domain from 20 to 50 degrees C. The temperature dependence of the molar ellipticity and mean-square radius of the cross section of a chain shows that the structure of CGMMV-RNA is more vulnerable than that of TMV-RNA. Such a different thermal stability of their structures was also reflected in the temperature dependence of the length and number of the constituent rods when the structures of the two RNA chains were represented by a model which consisted of rods joined with freely hinged joints. From these results, a possibility was suggested that the structural stability of CGMMV-RNA and TMV-RNA might be correlated with the infectivity of the corresponding virus, CGMMV and TMV, respectively.

Change of the persistence lengths in the conformational transitions of pullulan- and amylose-tricarbanilates.

With raising temperature in the domain of 20 to 60 degrees C, the intrinsic viscosity [eta] for pullulan-tricarbanilate PTC and amylose-tricarbanilate ATC in solutions was found to decrease, indicating that they exhibited thermal-induced conformational transition from expanded form to compact form. The persistence length P(l) of the chains, evaluated with small-angle X-ray scattering, has also decreased as the temperature is raised and, moreover, it significantly depended on the solvents employed, where as P(l) of pullulan, having no carbanilate groups, has exhibited neither temperature- nor solvent-dependence. The temperature dependence of [eta] for PTC and ATC was well elucidated in terms of the temperature-dependent P(l) with the wormlike chain model. From these results, it is suggested that intramolecular hydrogen bonds would be formed between carbanilate groups neighboring along the backbone chain, but they are gradually and cooperatively collapsed as the temperature is raised, inducing the conformational transition.

Conformation of poly(sodium ethacrylate) in solution studied by small-angle X-ray scattering.

The pH-induced conformational transition of poly(sodium ethacrylate) PNaEA in aqueous solution, which occurs between a compact form at low charge-density and an extended coil at high charge-density, was studied by small-angle X-ray scattering and the structure at an each conformational state was analyzed and compared with the corresponding one of poly(sodium methacrylate) PNaMA. The conformational transition for PNaEA induced a remarkable change in the scattering data plotted in the form of the Kratky plot. By comparing the scattering data with theoretical scattering functions, it was clarified that the structures of the compact form and the extended coil are well mimicked by a swollen gel having a network structure and by a wormlike chain, respectively. Although such a structure of the extended coil of PNaEA is similar to the corresponding one of PNaMA, the structure of the compact form of PNaEA is different from the corresponding one of PNaMA, which is still represented by a wormlike chain in a Theta medium.