Identification of a tomato UDP-arabinosyltransferase for airborne volatile reception.

Volatiles from herbivore-infested plants function as a chemical warning of future herbivory for neighboring plants. (Z)-3-Hexenol emitted from tomato plants infested by common cutworms is taken up by uninfested plants and converted to (Z)-3-hexenyl ß-vicianoside (HexVic). Here we show that a wild tomato species (Solanum pennellii) shows limited HexVic accumulation compared to a domesticated tomato species (Solanum lycopersicum) after (Z)-3-hexenol exposure. Common cutworms grow better on an introgression line containing an S. pennellii chromosome 11 segment that impairs HexVic accumulation, suggesting that (Z)-3-hexenol diglycosylation is involved in the defense of tomato against herbivory. We finally reveal that HexVic accumulation is genetically associated with a uridine diphosphate-glycosyltransferase (UGT) gene cluster that harbors UGT91R1 on chromosome 11. Biochemical and transgenic analyses of UGT91R1 show that it preferentially catalyzes (Z)-3-hexenyl ß-D-glucopyranoside arabinosylation to produce HexVic in planta.

Preparation of double-layered nanosheets containing pH-responsive polymer networks in the interlayers and their conversion into single-layered nanosheets through the cleavage of cross-linking points.

Double-layered nanosheets containing pH-cleavable polymer networks between two niobate layers were prepared by copolymerization of N-isopropylacrylamide and an acid-degradable crosslinker via surface-initiated atom transfer radical polymerization on the surface of hydrated interlayers (interlayer I) of K4Nb6O17·3H2O and subsequent exfoliation by the introduction of tetra-n-butylammonium (TBA) ions into anhydrous interlayers (interlayer II). Moreover, the double-layered nanosheets were converted into single-layered nanosheets by the cleavage of cross-linking points in polymer networks by lowering pH. Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG) results showed that polymer networks were present, and nanosheets with a thickness of 10.8 ± 1.6 nm were observed by using an atomic force microscope (AFM) after exfoliation using TBA ions. The thickness of the nanosheets was decreased to 6.1 ± 0.9 nm by lowering the pH, and proton nuclear magnetic resonance (1H NMR) and UV-vis spectroscopy showed that the degradation of the cross-linkers proceeded, suggesting that the cleavage of the cross-linking points led to the conversion of double-layered nanosheets into single-layered nanosheets.

Design of Microchannel Suitable for Packing with Anion Exchange Resins: Uranium Separation from Seawater Containing a Large Amount of Cesium.

We present a resin-packed microchannel that can reduce the radiation exposure risk and secondary radioactive wastes during uranium (U) separation by downscaling the separation using a microchip. Two types of microchips were designed to densely pack the microchannels with resins. The microchannels had almost the same cross-sectional area, but different outer circumferences. A satisfactory separation performance could be obtained by arranging more than ca. 10 resins along the depth and width of the microchannels. A resin-packed microchannel is an effective separation technique for determining the U concentration via inductively coupled plasma mass spectrometry owing to its ability to avoid the contamination of equipment by cesium, and to reduce the matrix effect. The size of the separation site was scaled down to <1/5000 compared to commonly used counterparts. The radiation exposure risk and secondary radioactive wastes can be reduced by 10- and 800-fold, respectively, using a resin-packed microchannel.

Advanced Top-Down Fabrication for a Fused Silica Nanofluidic Device.

Nanofluidics have recently attracted significant attention with regard to the development of new functionalities and applications, and producing new functional devices utilizing nanofluidics will require the fabrication of nanochannels. Fused silica nanofluidic devices fabricated by top-down methods are a promising approach to realizing this goal. Our group previously demonstrated the analysis of a living single cell using such a device, incorporating nanochannels having different sizes (102-103 nm) and with branched and confluent structures and surface patterning. However, fabrication of geometrically-controlled nanochannels on the 101 nm size scale by top-down methods on a fused silica substrate, and the fabrication of micro-nano interfaces on a single substrate, remain challenging. In the present study, the smallest-ever square nanochannels (with a size of 50 nm) were fabricated on fused silica substrates by optimizing the electron beam exposure time, and the absence of channel breaks was confirmed by streaming current measurements. In addition, micro-nano interfaces between 103 nm nanochannels and 101 µm microchannels were fabricated on a single substrate by controlling the hydrophobicity of the nanochannel surfaces. A micro-nano interface for a single cell analysis device, in which a nanochannel was connected to a 101 µm single cell chamber, was also fabricated. These new fabrication procedures are expected to advance the basic technologies employed in the field of nanofluidics.

Evaluation of an antibody-PNA conjugate as a clearing agent for antibody-based PNA-mediated radionuclide pretargeting.

Radionuclide molecular imaging of cancer-specific targets is a promising method to identify patients for targeted antibody therapy. Radiolabeled full-length antibodies however suffer from slow clearance, resulting in high background radiation. To overcome this problem, a pretargeting system based on complementary peptide nucleic acid (PNA) probes has been investigated. The pretargeting relies on sequential injections of primary, PNA-tagged antibody and secondary, radiolabeled PNA probe, which are separated in time, to allow for clearance of non-bound primary agent. We now suggest to include a clearing agent (CA), designed for removal of primary tumor-targeting agent from the blood. The CA is based on the antibody cetuximab, which was conjugated to PNA and lactosaminated by reductive amination to improve hepatic clearance. The CA was evaluated in combination with PNA-labelled trastuzumab, T-ZHP1, for radionuclide HER2 pretargeting. Biodistribution studies in normal mice demonstrated that the CA cleared ca. 7 times more rapidly from blood than unmodified cetuximab. Injection of the CA 6 h post injection of the radiolabeled primary agent [131I]I-T-ZHP1 gave a moderate reduction of the radioactivity concentration in the blood after 1 h from 8.5 ± 1.8 to 6.0 ± 0.4%ID/g. These proof-of-principle results could guide future development of a more efficient CA.

Multinuclear NMR Studies on Lewis Acid-Lewis Base Interactions between Bis(pentafluorophenyl)borinic Acid and Uranyl ß-Diketonato Complexes in Toluene.

In order to examine the possibility of Lewis acid-Lewis base (LA-LB) interactions between the boron atom of B(C6F5)2OH and the oxo groups ("yl" oxygen atoms) of uranyl ß-diketonato complexes, we have measured the 1H, 11B, 17O, 19F NMR and IR spectra of toluene solutions containing ß-diketonato complexes [UO2(acac)2DMSO or UO2(dfh)2DMSO, where acac = 2,4-pentanedionate, dfh = 1,1,1,2,2,6,6,7,7,7-decafluoroheptane-3,5-dionate, and DMSO = dimethyl sulfoxide] and B(C6F5)2OH. 11B and 17O NMR spectra of solutions containing UO2(dfh)2DMSO and B(C6F5)2OH showed no change in their chemical shifts regardless of the [B(C6F5)2OH]/[UO2(dfh)2DMSO] ratio. This indicates that there were no apparent interactions between B(C6F5)2OH and UO2(dfh)2DMSO. On the other hand, in the corresponding NMR spectra of solutions containing UO2(acac)2DMSO and B(C6F5)2OH, new signals were observed at a higher field than signals observed in the solutions containing only B(C6F5)2OH or UO2(acac)2DMSO, and their intensity changed with the [B(C6F5)2OH]/[UO2(acac)2DMSO] ratio. These results reveal that a complex with LA-LB interaction (B···O═U) between the boron atom of B(C6F5)2OH and the "yl" oxygen atom of UO2(acac)2DMSO was formed. IR spectra also supported such complex formation; i.e., the asymmetric O═U═O stretching band of UO2(acac)2DMSO was observed to shift from 897 to 810 cm-1 with the addition of B(C6F5)2OH. Moreover, 19F NMR spectra indicated that 1:1 and 2:1 LA-LB complexes exist in equilibrium, UO{OB(C6F5)2OH}(acac)2DMSO + B(C6F5)2OH = U{OB(C6F5)2OH}2(acac)2DMSO. The thermodynamic parameters for this equilibrium were obtained as K = (2.5 ± 0.6) × 102 M-1 (at 25 °C), ΔH = -42.4 ± 5.2 kJ mol-1, and ΔS = -96.7 ± 19.4 J K-1 mol-1. In 1H NMR spectra, the signal due to -CH groups of UO2(acac)2DMSO disappeared, and three signals due to the corresponding -CH groups newly appeared with an increase in the [B(C6F5)2OH]/[UO2(acac)2DMSO] ratio. From these phenomena, it is proposed that 1:1 and 2:1 LA-LB complexes having interactions between the -CH groups of acac and the -OH group of coordinated B(C6F5)2OH are formed depending on the [B(C6F5)2OH]/[UO2(acac)2DMSO] ratio.

Highly Efficient Surface Modification of Layered Perovskite Nanosheets with a Phosphorus Coupling Reagent Making Use of Microchannels.

Surface modification of niobate nanosheets in a double-Y-type microchannel was achieved for the first time using parallel flows of an aqueous dispersion of nanosheets derived from ion-exchangeable layered perovskite via delamination with a tetrabutylammonium hydroxide aqueous solution and a cyclohexane solution of oleyl phosphate. The surface modification was essentially completed within 4.6 s, and spectroscopic characterization (IR, solid-state 13C and 31P NMR) demonstrated the successful surface modification. The surface modification using a biphasic system in a vial using the same liquids required more than 4 h, indicating the extremely high efficiency of surface modification in the microchannel.

Expansion of Ion Effects on Water Induced by a High Hydrophilic Surface of a Polymer Network.

The spatial extent and anion-cation cooperativity of the ion effect on the structure and dynamics of water have long been debated but are still controversial. Previously, we experimentally demonstrated the extensive and cooperative effect of ions on water in a polyamide network by measuring the reflection wavelength (λ) on the ion sensor of poly(N-isopropylacrylamide) (PNIPAAm) hydrogel-immobilized photonic crystals. In the present study, we investigated the influence of the polymer surface on the ion effect by adopting a highly hydrophilic poly(N-isopropylacrylamide-co-N-acryloylaza-18-crown-6) hydrogel as a sensor matrix. In alkaline earth metal salt solutions, the copolymer hydrogel membrane sensor showed the redshift of λ for the specific combination of cations and anions, that is, Ca2+/Cl- and Sr2+/NO3-, which resulted from the concerted binding of ion pairs to the copolymer receptor. In alkali metal salt solutions, the ion sensor showed the blueshift of λ originating from the osmotic dehydration suppressed by the salts. The strength of the ion effect was evaluated by the average osmotic pressure (ΠA) required for the salt-inhibited dehydration in the early stage of hydrogel contraction. From the calculation results of ΠA for the copolymer and PNIPAAm hydrogels, it was found that the high hydrophilic copolymer surface more significantly enhanced the ion effect of structure-making cations (i.e., Li+) compared with borderline (Na+) and structure-breaking (K+ and Cs+) cations. Furthermore, the ion effect exhibited the higher ion cooperativity in combination with chloride anions than with nitrate anions. The enhancement of the long-range cooperative ion effect is derived from the expansion of the interactions between ions, water molecules, and the hydrophilic polymer network.

Boron-incorporating hemagglutinating virus of Japan envelope (HVJ-E) nanomaterial in boron neutron capture therapy.

Combining immunotherapeutic and radiotherapeutic technique has recently attracted much attention for advancing cancer treatment. If boron-incorporated hemagglutinating virus of Japan-envelope (HVJ-E) having high membrane fusion ability can be used as a boron delivery agent in boron neutron capture therapy (BNCT), a radical synergistic improvement of boron accumulation efficiency into tumor cells and antitumor immunity may be induced. In this study, we aimed to develop novel boron-containing biocompatible polymers modified onto HVJ-E surfaces. The copolymer consisting of 2-methacryloyloxyethyl phosphorylcholine (MPC) and methacrylamide benzoxaborole (MAAmBO), poly[MPC-co-MAAmBO], was successfully synthesized by using a simple free radical polymerization. The molecular structures and molecular weight of the poly[MPC-co-MAAmBO] copolymer were characterized by nuclear magnetic resonance and matrix-assisted laser desorption ionization time-of-flight mass spectrometry, respectively. The poly[MPC-co-MAAmBO] was coated onto the HVJ-E surface via the chemical bonding between the MAAmBO moiety and the sugar moiety of HVJ-E. DLS, AFM, UV-Vis, and fluorescence measurements clarified that the size of the poly[MPC-co-MAAmBO]-coated HVJ-E, HVJ-E/p[MPC-MAAmBO], to be about 130 ~ 150 nm in diameter, and that the polymer having 9.82 × 106 ~ 7 boron atoms was steadily coated on a single HVJ-E particle. Moreover, cellular uptake of poly[MPC-co-MAAmBO] could be demonstrated without cytotoxicity, and the hemolysis could be successfully suppressed by 20%. These results indicate that the HVJ-E/p[MPC-MAAmBO] may be used as boron nanocarriers in a combination of immunotherapy with BNCT.

Quantitative Evaluation of Long-Range and Cooperative Ion Effect on Water in Polyamide Network.

Despite long-standing research efforts to elucidate the specific ion effect on the structure and dynamics of water, the spatial extent affected by ions and the cooperativity of ions and counterions are still controversial. Here, we demonstrate an undoubtable evidence of long-range and cooperative ion effect on water molecules in a polyamide network by using a precision ion sensor of photonic crystal hydrogel membrane. The ion effect was quantitatively evaluated by means of the osmotic work per unit cell volume change of photonic crystal, Wunit, required for the ion-inhibited dehydration, which means a suppressed migration of water molecules by the extensive effect of ions beyond their immediate hydration shells. It was found that  Wunit required for 14 vol % contraction of the membrane sensor in LiCl aqueous solutions was 7.7 times larger than that in Sr(NO3)2 solutions. The combination of structure-making Ca2+ and Sr2+ with nitrate anions lowered the ion effect than the chloride salts of borderline Na+ and Ba2+. Furthermore, the nitrate salt of Sr2+ exhibited a lower ion effect than the chloride salts of structure-breaking K+ and Cs+. These results have revealed that the ion effect acts to water extensively, which is modulated by cooperative interactions of ions and counterions.

Direct Temperature-Swing Extraction of Rare-Earth Elements from Acidic Solution Using the Hydrophobic Interactions of Poly(N-isopropylacrylamide) with Diglycolamide-typed Ligands.

The phase transition-based gelification phenomenon of poly(N-isopropylacrylamide) [poly(NIPAAm)] has great potential in developing new waste-free extraction processes. In this study, we realized the direct and complete temperature-swing extraction of all trivalent rare-earth (RE) ions from a multi-component nitric acid solution onto a poly(NIPAAm) gel as chelate complexes with hydrophobic diglycolamide-typed ligands. Moreover, we elucidated that the extractabilities are affected by not only the coordination ability of the ligands with RE ions but also by the hydrophobic interaction between the poly(NIPAAm) and the ligands.

Synthesis and Evaluation of Thermoresponsive Boron-Containing Poly(N-isopropylacrylamide) Diblock Copolymers for Self-Assembling Nanomicellar Boron Carriers.

Development of new boron nanocarriers has been a crucial issue to be solved for advancing boron neutron capture therapy (BNCT) as an effective radiation treatment for cancers. The present study aimed to create a novel double-thermoresponsive boron-containing diblock copolymer based on poly(N-isopropylacrylamide) [poly(NIPAAm)], which exhibits two-step phase transitions (morphological transitions) at the temperature region below human body temperature. The boronated diblock copolymer considerably concentrates boron atoms into the water-dispersible (i.e., intravenous-administration possible) nanomicelles self-assembled by the first phase transition, and furthermore the properly controlled size and hydrophobicity of the second phase-transitioned nanoparticles are expected to make a significant contribution to the selective delivery and long-term retention of boron atoms into tumor tissues. Here we present the detailed synthesis of the strategic NIPAAm-based diblock copolymer with 3-acrylamidophenylboronic acid (PBA), i.e., poly(NIPAAm-block-NIPAAm-co-PBA), through a reversible addition-fragmentation chain transfer polymerization. Furthermore, the stepwise phase transition behavior of the obtained boronic-acid diblock copolymers was characterized in detail by temperature-variable ¹H and 11B-nuclear magnetic resonance spectroscopy. The phase-transition-induced molecular structural changes, including the structural compositions and sizes of nanomicelles and nanoparticles, are also discussed here.

Rapid Plasma Etching for Fabricating Fused Silica Microchannels.

In order to advance the performances of micro chemical and biochemical systems on a chip, the fabrication of microstructures such as channels and pillars is an essential basic technology. However, conventional fabrication methods based on wet etching have limitations in their applications for device engineering. In this study, we report on a new microchannel fabrication process on a fused silica substrate using photoresist and plasma etching based on C3F8, CHF3, and Ar gases. Deep, rectangular microchannels, having vertical angles close to 90°, 10 µm-scale deep and low surface roughness of less than 1 nm, could be fabricated on a fused silica substrate at high etching rates on the order of 5 - 7 nm s-1. This metal-free fabrication methodology is expected to be a low-cost, easy, and simple technique for a fused silica microstructure applications.

Temperature and Size Effects on Structural and Dynamical Properties of Water Confined in 1 - 10 nm-scale Pores Using Proton NMR Spectroscopy.

We were able to fill 1 - 10 nm-scale silica pores with water by vapor condensation, and examined the freezing phenomena, structures, and molecular motions of the confined water in the temperature range from 293 to 188 K by 1H-NMR spectroscopy. The results showed that almost all water molecules confined in 10 nm-scale pores were frozen and that approximately half of the water confined in 1 nm-scale pores existed in the liquid state even below the freezing point. The water adsorbed on the pore surfaces was estimated as a monolayer in 2.58 nm pores and bi- and tri-layers in 6.48 nm and larger pores, respectively. Furthermore, it was clarified from the proton relaxation rate (1H-1/T1) measurements that the molecular motions of adsorbed water itself were restricted by nanoconfinement and were extremely dependent on the conditions of proton exchange and hydrogen bond rearrangements of the adsorbed water.

Fabrication of Hydrophobic Nanostructured Surfaces for Microfluidic Control.

In the field of micro- and nanofluidics, various kinds of novel devices have been developed. For such devices, not only fluidic control but also surface control of micro/nano channels is essential. Recently, fluidic control by hydrophobic nanostructured surfaces have attracted much attention. However, conventional fabrication methods of nanostructures require complicated steps, and integration of the nanostructures into micro/nano channels makes fabrication procedures even more difficult and complicated. In the present study, a simple and easy fabrication method of nanostructures integrated into microchannels was developed. Various sizes of nanostructures were successfully fabricated by changing the plasma etching time and etching with a basic solution. Furthermore, it proved possible to construct highly hydrophobic nanostructured surfaces that could effectively control the fluid in microchannels at designed pressures. We believe that the fabrication method developed here and the results obtained are valuable contributions towards further applications in the field of micro- and nanofluidics.

Keto-Enol Tautomeric Equilibrium of Acetylacetone Solution Confined in Extended Nanospaces.

We aim to clarify the effects of size confinement, solvent, and deuterium substitution on keto-enol tautomerization of acetylacetone (AcAc) in solutions confined in 10-100 nm spaces (i.e., extended nanospaces) using (1)H NMR spectroscopy. The keto-enol equilibrium constants of AcAc (K(EQ) = [keto]/[enol]) in various solvents confined in extended nanospaces of 200-3000 nm were examined using the area ratios of -CH3 peaks in keto to enol forms. The results showed that the keto form of AcAc in hydrogen-bonded solvents such as water and ethanol increased drastically with decreasing space sizes below about 500 nm, but the size confinement did not induce equilibrium shifts in aprotic solvents such as DMSO. The magnitudes of K(EQ) enhancement were well correlated with solvent proton donicity. It followed from the determination of thermodynamic parameters that the stabilization of intermolecular interactions between protons in water and carbonyl oxygen (C═O) in the keto form of AcAc were promoted by size-confinement, and that the keto form could be energetically and structurally favored in extended nanospaces vis-à-vis the bulk space. Furthermore, the measurements of deuterium dependence of the K(EQ) values verified that the nanoconfinement-induced shifts of keto-enol tautomerization of AcAc are attributable to high proton mobility via a proton hopping mechanism of the confined water.

Dielectric constant of liquids confined in the extended nanospace measured by a streaming potential method.

Understanding liquid structure and the electrical properties of liquids confined in extended nanospaces (10-1000 nm) is important for nanofluidics and nanochemistry. To understand these liquid properties requires determination of the dielectric constant of liquids confined in extended nanospaces. A novel dielectric constant measurement method has thus been developed for extended nanospaces using a streaming potential method. We focused on the nonsteady-state streaming potential in extended nanospaces and successfully measured the dielectric constant of liquids within them without the use of probe molecules. The dielectric constant of water was determined to be significantly reduced by about 3 times compared to that of the bulk. This result contributes key information toward further understanding of the chemistry and fluidics in extended nanospaces.

Extended nanospace chemical systems on a chip for new analytical technology.

Integration of chemical processes on a microchemical chip has gained much attention in the past decade, and the basic concepts of micro-integration and the supporting technologies have been intensively developed. As a result, many analytical and chemical synthesis applications were demonstrated. The superior performances were verified including shortening analysis time, decrease of sample and reagent volume, and easy chemical operations. Now, the micro-technologies are moving toward practical applications by establishing the systems in which the microchemical chip works as chemical central processing unit. Recently, as a new research field, integration is further proceeding to the 10(1)-10(3) nm scale, which we call extended nanospace. The extended nanospace locates the gap between the targets of conventional nanotechnology (10(0)-10(1) nm) and micro-technology (>1 µm), and the fluidics and chemistry have not been explored well due to a lack of fundamental technologies. For these purposes, many methodologies were established in recent years. Unique liquid properties were reported, which were quite different from those in microspace. Some properties can be expected by considering the characteristics of microspace and the downscaling, and the others are unexpected or are difficult to predict. These properties enabled new chemical operations which will be quite important as the next analytical technologies. Now, chemistry and fluidics in the extended nanospace are forming a new research field. In this review, we survey the fundamental technologies for extended nanospace researches and introduce several unique liquid properties. Finally, unique chemical operations are also illustrated leading to new analytical operations.

Extended-nano fluidic systems for analytical and chemical technologies.

Recently, integrated chemical systems have been further downscaled to the 10(1)-10(3) nm scale, which we call extended-nano space. The extended-nano space is a transient space from single molecules to bulk condensed phase, and fluidics and chemistry have not been explored. One of the reasons is the lack of research tools for the extended-nano space, because the space locates the gap between the conventional nanotechnology (10(0)-10(1) nm) and microtechnology (>1 microm). For these purposes, basic methodologies were developed such as nanofabrication, fluidic control, detection methods, and surface modification methods. Especially, fluidic control is one of the important methods. By utilizing the methodologies, new specific phenomena in fluidics and chemistry were reported, and the new phenomena are increasingly applied to unique applications. Microfluidic technologies are now entering new research phase combined with the nanofluidic technologies. In this review, we mainly focus on pressure-driven or shear-driven extended-nano fluidic systems and illustrate the basic nanofluidics and the representative applications.