Nucleic acid-based fluorescent sensor systems: a review

Nucleic acids have been actively applied to various sensing tools and future biodevices because of their high biocompatibility, as well as their programmable properties and functions. 

  • Aya Shibata
  • Sayuri L. Higashi
  • Masato Ikeda
Review

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  • Development of reverse osmosis membranes by incorporating polyhedral oligomeric silsesquioxanes (POSSs)

    Reverse osmosis (RO) membranes composed of polyamides and cellulose acetates are used as separation layers in pure-water production. However, improving the separation performance and antifouling properties of RO membranes is necessary. This focus review described the composite reverse osmosis membranes with optimal amounts of polyhedral oligomeric silsesquioxanes (POSS), which are cage-shaped, subnanosized molecules exhibiting organic–inorganic hybrid structures, showed improved water flux, NaCl rejection, antichlorine and antifouling properties, and mechanical strength.

    • Kazuki Yamamoto
    Focus Review
  • Functionalization of keratin nanoparticles by their internal modifications

    Nanosized keratin particles (Ker-DODAC) were prepared via the assembly of keratin chains with the aid of a cationic surfactant. The obtained nanoparticles (Ker-DODACss) possessed a hydrophobic core composed of surfactants. To modify its internal environment, cholesterol was loaded to nanoparticles. The obtained nanoparticles (Ker-DODACss-Chol) showed retention and release of payloads in response to multiple stimuli. Also, lipophilic antioxidants, α-tocopherol, was loaded to Ker-DODACss-Chol to prevent α-tocopherol from an oxidative degradation and to preserve the antioxidant activity.

    • Yuuka Fukui
    • Kaori Ito
    • Keiji Fujimoto
    Original Article
  • Supramolecular nylon-based actuators with a high work efficiency based on host–guest complexation and the mechanoisomerization of azobenzene

    Supramolecular nylon-based materials exhibited changes in their Young’s moduli and underwent bending upon irradiation with UV light as a result of isomerization in 1:2 complexes of γ-cyclodextrin and azobenzene. The photoisomerization of azobenzenes led to photoresponsive actuation of the supramolecular materials. The movable cross-links contributed to the mechanical toughness and photoresponsive actuation of these materials. Shape restoration of the nylon-based materials resulted in an extraordinarily high work efficiency.

    • Junsu Park
    • Hiroki Tamura
    • Yoshinori Takashima
    Original Article
  • A comprehensive study of the structure and piezoelectric response of biodegradable polyhydroxybutyrate-based films for tissue engineering applications

    The results of comprehensive research on the thermal behavior, molecular and crystalline structures of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB-HV) films of different thicknesses, their molecular weights (Mw) and 3-hydroxyvalerate (3-HV) contents are reported. The film thickness affects the PHB film crystalline structure and crystallinity. A decrease in Mw leads to a smaller number of piezoactive domains in PHB films. The addition of HV significantly reduces the crystallinity and piezoresponse of PHB films. A decrease in Mw results in the increased crystallinity of PHB-HV films.

    • Roman V. Chernozem
    • Igor O. Pariy
    • Maria A. Surmeneva
    Original Article
  • Bioinspired macromolecular templates for crystallographic orientation control of ZnO thin films through zinc hydroxide carbonate

    An approach inspired by biomineralization has allowed us to develop various organic/inorganic hybrid materials with environmental benignity. In the present study, we have achieved the orientation control of zinc hydroxide carbonate (ZHC) thin-film crystals through the chemical structures and morphologies of the templates. After the thermal treatment of the ZHC thin films, the crystal orientations of the resultant zinc oxide (ZnO) thin films are maintained. The effects of the thickness and annealing time for the polymer templates on the formation of ZnO thin films have been examined.

    • Takahiro Mikami
    • Shunichi Matsumura
    • Takashi Kato
    Original Article Open Access
  • CHCl3/triethanolamine: a new mixed solvent for preparing high-molecular-weight main-chain benzoxazines through Mannich-type polycondensation

    Mannich-type polycondensation of diamines, bisphenols and PF was conducted in CHCl3, CHCl3/triethylamine, and CHCl3/triethanolamine, respectively. The products were greatly affected by the solvents used. Owing to the combination of alkalinity and solvation effect of triethanolamine, CHCl3/triethanolamine was preferable for Mannich-type polycondensation which gave main-chain benzoxazines possessing Mn up to 10,000, oxazine content >80.0% and yield >96.0%.

    • Ping Wang
    • Xuya Liu
    • Po Yang
    Original Article
  • Synthesis of polycarbonates and polycarbonate/polyester copolymers through an ester-carbonate exchange reaction

    We describe the synthesis of polycarbonate (PC) by means of the polycondensation of diol formate and dialkyl carbonate through an ester-carbonate exchange reaction. Furthermore, the polycondensation of diol formate and diethyl carbonate in the presence of polyester (PEs) under reduced pressure affords a statistical copolymer of PC and PEs. The composition of PC and PEs in the copolymer can be arbitrarily altered by changing the feed ratio of the monomers to PEs.

    • Takayoshi Katoh
    • Maai Saso
    • Tsutomu Yokozawa
    Original Article
  • Role of the nucleating agent masterbatch carrier resin in the nonisothermal crystallization kinetics of polypropylene

    The effect of the nucleating agent masterbatch carrier resin on the nonisothermal crystallization of a pipe-grade polypropylene block copolymer was investigated at three different cooling rates using differential scanning calorimetry (DSC). Crystallization kinetic parameters obtained from DSC cooling curves showed that incorporation of a nucleating agent by means of a masterbatch increased the crystallization rate by approximately two times compared to that of the sample with the same concentration of nucleating agent without the use of a masterbatch.

    • Maryam Shokrollahi
    • Bahereh T. Marouf
    • Reza Bagheri
    Rapid Communication
  • Polyion complex (PIC) micelles formed from oppositely charged styrene-based polyelectrolytes via electrostatic, hydrophobic, and π–π interactions

    A pair of the oppositely charged diblock copolymer was used to prepare the polyion complex (PIC) micelle by mixing them in an aqueous medium using electrostatic, hydrophobic, and π–π interactions. The PIC micelles attained the maximum size and aggregation number when the charges of the cationic and anionic blocks were neutralized. The PIC micelle was stable against NaCl because the core was formed by electrostatic, hydrophobic, and π–π interactions. The micelle can encapsulate charge and hydrophobic guest molecules.

    • Thu Thao Pham
    • Tien Duc Pham
    • Shin-ichi Yusa
    Original Article