Search

According to current research, cancer cell growth is suppressed by ω-3 fatty acids, which are essential fatty acids. On the other hand, ω-3 fatty acids are metabolized to bioactivities in vivo. A systematic evaluation of the ability of ω-3 fatty acids and their metabolites to suppress cancer cell growth has not been sufficiently conducted. Our work evaluated the effect of ω-3 fatty acids (docosahexaenoic acid, eicosapentaenoic acid), trans fatty acid, and the metabolites (Resolvin E1, Maresin 1) on cancer cell growth suppressibility. Our results suggest that there may be optimal fatty acids depending on the kind of cancer cells, the presence or absence of hydroxyl group, and the double bond structure involved.

The optimal conditions for fabricating a screen-printed diamond electrode for the sensitive detection of l -cysteine (Cys), a non-essential amino acid, were investigated. As-grown (AG-), hydrogen-terminated (H-) and oxygen-terminated boron-doped diamond powders (O-BDDP) were prepared, and BDDP-printed electrodes were fabricated using BDDP-containing inks. Comparing the linear sweep voltammograms of Cys at AG-BDDP-, H-BDDP-, and O-BDDP-printed electrodes, among the three samples, the H-BDDP-printed electrode was found to be the most suitable for the sensitive detection of Cys at low concentrations, showing a steep slope in its calibration curve and a low background current density. In addition, the H-BDDP-printed electrode exhibited a lower limit of detection (0.620 μM) and a more negative oxidation peak potential (+0.663 V vs. Ag/AgCl) and wider linear concentration range (1–194 μM) than a H-boron-doped diamond (BDD) thin-film electrode. It is thought that a slight amount of sp2 carbon on the BDDP contributed to these optimal properties. Using the H-BDDP-printed electrode, Cys was detected in a solution containing electroactive interferents (glutathione and methionine) with a recovery of 86–104%. Therefore, it was concluded that the H-BDDP-printed electrode can be used as a highly sensitive and disposable electrochemical sensor for Cys detection.

This study investigates the effect of chemical surface termination on the electrochemical characteristics of boron-doped diamond powder (BDDP). The aim is to realize highly sensitive electrochemical detection of ciprofloxacin (CIP) on BDDP-printed electrodes. To this end, we prepared oxygen-terminated BDDP (O-BDDP) and hydrogen-terminated BDDP (H-BDDP), and mixed them with an insulating polyester (PES) resin binder to obtain BDDP ink for the printed electrode. Scanning electron microscopy of the BDDP-printed electrodes revealed that the O-BDDPs were partially covered with PES resin, while the H-BDDPs were entirely covered with resin. This structural difference might explain the lower charge-transfer resistance of the Ru(NH3)62+/3+ redox reaction at the O-BDDP-printed electrode than at the H-BDDP-printed electrode. The slope of the calibration curve of the linear sweep voltammogram of CIP was steeper at the O-BDDP-printed electrode than at the H-BDDP-printed electrode and the O-BDD thin-film electrode, and was similar to that at the H-BDD thin-film electrode. Using the O-BDDP-printed electrode, we determined the CIP in artificial buffer-diluted urine in the concentration range 1–30 μM with a recovery of 107%. We conclude that the O-BDDP-printed electrodes provide a highly sensitive and disposable electrochemical sensor for CIP detection.

A simple water treatment system consisting of a deep UV light (λ = 222 nm) source, a mesoporous TiO2/boron-doped diamond (BDD) photocatalyst, and a BDD electrode was prepared and used to decompose sulfamethoxazole (SMX) in an advanced oxidation process. The mesoporous TiO2/BDD photocatalyst used with the electrochemical treatment promoted SMX decomposition, but the mesoporous TiO2/BDD photocatalyst alone had a similar ability to decompose SMX as photolysis. Fragments produced through photocatalytic treatment were decomposed during the electrochemical treatment and fragments produced during the electrochemical treatment were decomposed during the photocatalytic treatment, so performing the electrochemical and photocatalytic treatments together effectively decomposed SMX and decrease the total organic carbon concentration to a trace.

Porphyrin selectively shows tumour accumulation and has attracted attention as a carrier molecule for drug delivery systems (DDS). Porphyrin has two functional sites termed the meso- and β-positions. In previous work, meso-porphyrin derivatives with an alkyl group were found to exhibit greater accumulation in human breast cancer cells (MCF-7). To identify the correlation between porphyrin accumulation and functional porphyrin positions of other functional groups, the accumulation of porphyrin derivatives with a phenyl group was investigated. The β-porphyrin derivative with a phenyl group showed higher accumulation in MCF-7 cells and greater affinity for albumin than the meso-porphyrin derivative. The results of density functional theory (DFT) calculations suggest that the β-porphyrin derivative with a phenyl group had higher planarity across the total structure than the meso-porphyrin derivative. It was concluded that the greater planarity of the β-porphyrin derivative with a phenyl group might lead to superior MCF-7 cell accumulation.

Lightning strikes cause nitrogen to dissolve in water and form reactive nitrogen and oxygen species, which form natural fertilizers that can be absorbed through plant roots. Such processes during rainstorm events can be simulated by applying plasma to a solution. Plasma-activated water (PAW) has great potential as a source of various dissolved reactive chemical species. Different mixtures of species are produced using different solution compositions. Here, basil seeds were grown in PAW to prevent blooms of

Boron-doped diamond (BDD) electrodes have a wide potential window and can produce ozone by water electrolysis at high voltage. Though ozone has strong oxidative power (standard oxidation potential: 2.07 V vs. NHE), it cannot decompose certain types of recalcitrant organic matter completely. We developed an advanced oxidation process (AOP), in which hydroxy radicals with stronger oxidative power (standard oxidation potential: 2.85 V vs. NHE) are formed using a combination of ozone, photocatalyst, and UV. In this study, we fabricated a mesoporous TiO2/BDD hybrid electrode and examined its potential for AOPs. A synergetic effect between electrochemical water treatment and photocatalytic water treatment was observed with the hybrid electrode that did not occur with the BDD electrode.

Ammonium ions were formed by electrochemical oxidation of urea with a boron-doped diamond (BDD) electrode. Almost complete decomposition of urea was achieved. When the BDD electrode was used together with a mesoporous titanium dioxide photocatalyst, the amount of ammonium ions produced increased.

Herein, a conductive boron-doped nanodiamond (BDND) particle is prepared as an electrode material for an aqueous electric double-layer capacitor with high power and energy densities. The BDND is obtained by depositing a boron-doped diamond (BDD) on a nanodiamond particle substrate with a primary particle size of 4.7 nm via microwave plasma-assisted chemical vapor deposition, followed by heat treatment in air. The BDND comprises BDD and sp

Porphyrin derivatives accumulate selectively in cancer cells and are can be used as carriers of drugs. Until now, the substituents that bind to porphyrins (mainly at the meso-position) have been actively investigated, but the effect of the functional porphyrin positions (β-, meso-position) on tumor accumulation has not been investigated. Therefore, we investigated the correlation between the functional position of substituents and the accumulation of porphyrins in cancer cells using cancer cells. We found that the meso-derivative showed higher accumulation in cancer cells than the β-derivative, and porphyrins with less bulky substituent actively accumulate in cancer cells. When evaluating the intracellular distribution of porphyrin, we found that porphyrin was internalized by endocytosis and direct membrane permeation. As factors involved in these two permeation mechanisms, we evaluated the affinity between porphyrin-protein (endocytosis) and the permeability to the phospholipid bilayer membrane (direct membrane permeation). We found that the binding position of porphyrin affects the factors involved in the transmembrane permeation mechanisms and impacts the accumulation in cancer cells.

Here, we report the first synthesis of polycrystalline boron-doped diamond (BDD) by an In-liquid microwave plasma CVD (IL-MPCVD) process from a mixture of alcohols and boron trioxide (B2O3). We simultaneously achieved high growth rates (up to 287 μm/h) and high boron concentrations (up to 7 × 1021 cm−3). We examined the growth mechanism and show that water generated by dissolution of B2O3 in the alcohol is key to rapid growth of BDD. Even with the same C:H:O ratio, diamond growth rate and nucleation density drastically decreased by addition of water. Water has a strong etching effect, which shifts diamond to grow in carbon rich conditions. Finally, we evaluated the as-grown BDD film as a diamond electrode. Our IL-MPCVD-grown BDD showed electrochemical properties comparable to those of BDD grown by the conventional CVD process in terms of its potential window (3.2 V) and peak separation (85 mV) in 1 mM K3[Fe(CN)6]. Owing to the high growth rate, IL-MPCVD is an effective technique for synthesizing BDD.

Understanding the fundamentals of photoelectrocatalytic (PEC) biomolecular oxidation benefits the development of next-generation PEC biosensors. In this work, single-step electrospun titanium-di-oxide-gold (TiO

We report a simple room-temperature synthesis route for increasing the reactivity of a TiO2 photocatalyst using a solution plasma process (SPP). Hydrogen radicals generated from the SPP chamber interact with the TiO2 photocatalyst feedstock, transforming its crystalline phase and introducing oxygen vacancy defects. In this work, we examined a pure anatase TiO2 as a model feedstock because of its photocatalytic attributes and well-characterized properties. After the SPP treatment, the pure anatase crystalline phase was transformed to an anatase/brookite heterocrystalline phase with oxygen vacancies. Furthermore, the SPP treatment promoted the absorption of both UV and visible light by TiO2. As a result, TiO2 treated by the SPP for 3 h showed a high gaseous photocatalytic performance (91.1%) for acetaldehyde degradation to CO2 compared with the activity of untreated TiO2 (51%). The SPP-treated TiO2 was also more active than nitrogen-doped TiO2 driven by visible light (66%). The overall photocatalytic perfor...

Platinum nanoparticle-supported boron-doped diamond powder (Pt/BDDP) was prepared and investigated as a durable polymer electrolyte fuel cell (PEFC) cathode catalyst. The use of the nanocapsule method enabled dense deposition of Pt nanoparticles (2–5 nm in size) on a boron-doped diamond (BDD) powder

We focused on a micro diamond (MD) particle with the highest thermal conductivity among existing materials and aimed to make a MD/copper composite material by electroplating. However, copper is naturally non-wetting with MD due to its chemical incompatibility, leading to weak interfacial bonding and high thermal resistance. We improved the wettability between MD and copper functionalized by the amino group on the MD using a photocatalytic reaction. The functionalization of the diamond surface by amino groups was achieved by treating the MDs in a 3-aminopropyltrimethoxysilane-containing solution. The amino group functionalized MD was dispersed in the electroplating bath, where copper was deposited on the MD. As a result, the composite material of amino group functionalized MD assisted by photocatalyst and copper improved their interfacial affinity and exhibited the high thermal conductivity of 595 W/m K.

Diacylglycerides (DAGs) constitute an important category of lipids owing to their ability to form a lipid membrane, which can be used in a wide variety of biomedical applications. DAGs often include a zwitterionic polar headgroup that can influence the properties of the lipid membrane (e.g., protein adsorption, ion binding, hydration, membrane fluidity, phase stability) and affect their applicability. To clarify the effect of the charge arrangement of zwitterionic headgroups on intermolecular interactions in the DAG bilayers, we investigated the intermolecular interaction between a naturally occurring DAG (1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)) and synthetic DAGs (which is called “inverse charge zwitterlipids (ICZLs)”) whose headgroup charges were antiparallel with respect to those of DPPC. We used 1,2-dipalmitoyl-sn-glycero-3-carboxybetaine (DPCB) and 1,2-dipalmitoyl-sn-glycero-3-sulfobetaine (DPSB) as ICZLs and compared two combinations of the lipids (DPPC–DPCB and DPPC–DPSB). We obtained surface pressure–area (π–A) isotherms to elucidate the intermolecular interaction between the lipids in the monolayer at the air/water interface. We found shrinkage of the area per molecule in both lipid combinations, indicating that mixing DPPC with ICZLs results in an attractive intermolecular force. As an overall trend, the degree of shrinkage of the mixed monolayer and the thermodynamic favorability of mixing were greater in the DPPC–DPCB combination than in the DPPC–DPSB combination. These trends were also observed in the lipid bilayers, as determined from the gel-to-liquid crystal phase transition temperature (Tc) of the aqueous dispersion of the lipid vesicles. In the highly compressed lipid monolayers and vesicles (lipid bilayer), the molar fractions of ICZLs, in which the intermolecular interaction reached a maximum, were 0.6–0.8 for the DPPC–DPCB combination and 0.5 (equimolar composition) for the DPPC–DPSB combination. Therefore, in the compressed monolayers and bilayers, the mechanism of intermolecular interaction between DPPC and DPCB is different from that between DPPC and DPSB.

Porphyrin is accumulated in tumours due to its interaction with protein. Cancer therapy with porphyrin as a carrier molecule is attracting attention. Porphyrin displays two functional sites termed β- and meso-positions. A correlation between the functional position on the porphyrin molecule and the ability to accumulate in cancer cells is observed in the present study. The accumulation of porphyrin derivatives was determined by measuring fluorescence intensity after incubation for 2 and 24 h. The accumulation of cancer cells depended on the position and length of functional groups. Estimated binding constants between porphyrin and bovine serum albumin suggest that the position of functional groups leads to changes in binding affinity and influences the accumulation of porphyrin derivatives in cancer cells.

Herein, a conductive boron-doped nanodiamond (BDND) particle is prepared as an electrode material for an aqueous electric double-layer capacitor with high power and energy densities. The BDND is obtained by depositing a boron-doped diamond (BDD) on a nanodiamond particle substrate with a primary particle size of 4.7 nm via microwave plasma-assisted chemical vapor deposition, followed by heat treatment in air. The BDND comprises BDD and sp2 carbon components, and exhibits a conductivity above 1 S cm−1 and a specific surface area of 650 m2 g−1. Cyclic voltammetry measurements recorded in 1 M H2SO4 at a BDND electrode in a two-electrode system shows a capacitance of 15.1 F g−1 and a wide potential window (cell voltage) of 1.8 V, which is much larger than that obtained at an activated carbon electrode, i.e., 0.8 V. Furthermore, the cell voltage of the BDND electrode reaches 2.8 V when using saturated NaClO4 as electrolyte. The energy and power densities per unit weight of the BDND for charging–discharging in 1 M H2SO4 at the BDND electrode cell are 10 Wh kg−1 and 104 W kg−1, respectively, and the energy and power densities per unit volume of the BDND layer are 3–4 mWh cm−3 and 10 W cm−3, respectively. Therefore, the BDND is a promising candidate for the development of a compact aqueous EDLC device with high energy and power densities.

Techniques for large-area pattern formation on polymeric substrates are important for fabricating a large variety of functional devices, such as flexible electronics, tunable optical devices, adhesives, and so on. The present study demonstrates a method for pattern formation on poly(dimethylsiloxane) that involves grafting methacrylate polymers through photo-initiated polymerization. The influence of substrate stiffness and monomers type on pattern formation was investigated. Firstly, the stiffness of the substrate was found to affect the topology of the patterns produced. The gap width of convex regions of the pattern was enlarged with decreasing stiffness. It was found that the gap width trended in a manner that was consistent with previous reports, but in this study, relatively large gap widths were observed compared with those from previous studies. Secondly, it was revealed that the solubility of the monomer in the poly(dimethylsiloxane) precursor was the dominant factor in determining whether or not pattern formation occurred. When using insoluble monomers (glycidyl methacrylate and benzyl methacrylate), characteristic patterns were observed. It is speculated that intermolecular attractive forces between the grafted polymers induce lateral aggregation on the substrate, resulting in buckling instability of the grafted polymer layer caused by a mismatch in the equilibrium between the grafted polymer layer and the substrate. Copyright © 2017 John Wiley & Sons, Ltd.

A boron-doped diamond (BDD) electrode with a large specific surface area was fabricated by formation of a hierarchical nanostructure. A BDD thin film was deposited on a silicon pillar array substrate fabricated using photolithography to obtain a BDD pillar array (BDD-PA). The BDD-PA was subjected to a two-step thermal treatment to form dense pores on the surface (P-BDD-PA). The P-BDD-PA was then treated by reactive ion etching (RIE) to form nanowhiskers on the surface (P-BDDW-PA). The combination of these structures (pillar array, pores and nanowhiskers) enabled enhanced double-layer capacitance (ca. 2800 μF cm − 2 ) based on the enlarged specific surface area without narrowing of the potential window (ca. 3 V) in an aqueous electrolyte. The combination of the two-step thermal treatment and RIE treatment should be an effective post-treatment method for enhancement of the capacitance of porous BDD materials consisting of micrometer-sized structures without significant increase of the time constant.

A liposome is a molecular assembly in the form of a vesicle comprised of a phospholipid bilayer. Liposomes can be used as molecular containers in various fields such as pharmaceutical, cosmetic, and food industries. It is difficult to maintain the original structure of liposomes in an aqueous medium. Phospholipids, which are components of liposomes, are susceptible to hydrolysis, which causes disruption of the liposomal structure and dysfunction of the molecular container. In this context, freeze-drying liposomes is a preferable method to improve the shelf life of liposomes. However, when freeze-drying liposomes, a lyoprotective agent is required to preserve their original structure. In this study, we investigate whether alkyl sulfobetaines (SBn, n: number of carbons in the alkyl chain, n = 1-18) can be used as lyoprotectants for 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes. The results indicated that the length of the alkyl chain of the SBn was an important factor to prevent liposome disruption during the freeze-drying and subsequent rehydration processes. The use of SBn with an alkyl chain of intermediate length (n = 6-10) could prevent liposome disruption and remarkably reduce the gel-to-liquid crystal phase transition temperature (Tm) of the freeze-dried liposomes. This indicates that these SBn could intercalate in the dried bilayer and reduce intermolecular interaction between DPPC in the bilayer. The Tm reduction of the freeze-dried liposomes should contribute to prevention of the gel-to-liquid phase transition of the liposomes during the rehydration process, which has been known to be a main cause of liposome disruption. We expect that the results from this study will provide an insight into the influence of zwitterionic additives on freeze-dried lipid bilayers and the lyoprotective effect, which should be useful in many biochemical and biomedical fields.

In this study, the validity of TiO2-based photocatalysts anti-algal effects was examined with Chlorella vulgaris. Cu-modified TiO2 (without N dopants) showed clear anti-algal effect under white LED light. N-doped TiO2 (both with and without Cu modification) and Cu-modified TiO2 (without N dopants) showed clear anti-algal effects when UV light was used together with white LED light. S-doped TiO2 had no anti-algal effects and even promoted the growth of algae. The degree of the anti-algal effect differed depending on the dopants, surface modifications, and irradiation light. Photocatalysts create several active spices during their photocatalytic processes. Of these, the effects of superoxide radical (O 2 ·− ) and hydrogen peroxide (H2O2) on algae growth were examined. Photocatalysts with high anti-algal effect produced hydrogen peroxides effectively, while there was no correlation between productivity of superoxide radical and anti-algal effects. Thus, the ability to produce hydrogen peroxide is a plausible factor for determining the efficiency of the anti-algal effect of a photocatalysts.

Electrolytic cells for electrochemical oxygen demand (ECOD) measurements based on total electrolytic decomposition at a boron-doped diamond (BDD) electrode were developed for rapid measurement of organic pollutants at low concentrations. Using improved electrolytic cells designed for efficient mass transfer, the ECOD for 10 μM potassium hydrogen phthalate (theoretical ECOD: 2.3 mg-O2 L-1) was determined in a relatively short electrolysis time. Thus, ECOD measurements using these cells would be useful for estimating organic water pollution in industrial waste and lake water.

Intermolecular interactions between lipid molecules are important when designing lipid bilayer interfaces, which have many biomedical applications such as in drug delivery vehicles and biosensors. Phosphatidylcholine, a naturally occurring lipid, is the most common lipid found in organisms. Its chemical structure has a negatively charged phosphate linkage, adjacent to an ester linkage in a glycerol moiety, and a positively charged choline group, placed at the terminus of the molecule. Recently, several types of synthetic lipids that have headgroups with the opposite charge to that of phosphatidylcholine have emerged; that is, a positively charged ammonium group is present adjacent to the ester linkage in their glycerol moiety and a negatively charged group is placed at their terminus. These types of lipids constitute a new class of soft material. The aim of this study was to determine how such lipids, with antiparallel arranged headgroup charge, interact with naturally occurring phosphatidylcholines. We synthesized 1,2-dipalmitoyl-sn-glycero-3-sulfobetaine (DPSB) to represent a reversed-head lipid; 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) was used to represent a naturally occurring phospholipid. The intermolecular interaction between these lipids was investigated using surface pressure-area (π-A) isotherms of the lipid monolayer at the air/water interface. We found that the extrapolated area and excess free energy of the mixed monolayer deviated negatively when compared with the ideal values from additivity. Moreover, differential scanning calorimetry of the lipid mixture in aqueous dispersion showed that the gel-to-liquid crystal transition temperature increased compared with that of each pure lipid composition. These results clearly indicate that DPSB preferably interacts with DPPC in the mixture. We believe that the attraction between the oppositely charged headgroups of these lipids reinforces the intermolecular interaction. Our results provide insight into the intermolecular interaction between phospholipids and reversed-head lipids, which may prove useful for the design of lipid-based materials in the future.

A coating was developed by controlling its glass transition temperature (Tg). This coating attained its highest Tg value in wet conditions (wet Tg) of higher than 100 °C, and maintained its adhesion on stainless steel even after immersion in boiling water. When this coating material was applied to a conventional two-component epoxy structural adhesive as a metallic primer, it improved the primer adhesion durability on the stainless steel sheet in water significantly, even if it was not chemically modified (without pretreatment). This indicated that a relative weak hydrogen bond between the hydroxyl group of the epoxy network and a surface hydroxyl group of the oxide layer of the stainless steel could be sufficient to prevent water penetration into the interface if the thermal mobility of the epoxy network is restrained. An investigation by X-ray photoelectron spectroscopy (XPS) indicated an interaction between a primer amino-group component and the metallic surface accompanied by proton transfer. However, the thermal mobility of the epoxy network could be the most important factor in its adhesion in wet conditions.

The surface of nanodiamond (ND) particles was modified with 1-octadecene via a simple thermal reaction to obtain octadecyl-modified ND. Fourier transform infrared spectroscopy and thermogravimetric analysis results indicated that octadecyl groups were successfully introduced onto the ND surface. The amount of the octadecyl groups on the ND surface was observed to increase with increasing reaction time and to eventually saturate. A bead-milling process, which enabled disaggregation of NDs in 1-octadecene, was observed to increase the amount of octadecyl groups adsorbed onto the ND surface. The estimated surface coverage was as high as 2.2 × 1014 molecules cm−2, which corresponds to submonolayer level. Dispersion tests revealed that the octadecyl-modified ND particles exhibit hydrophobic/lipophilic character, whereas the oxidized ND (before surface modification with 1-octadecene) exhibited good dispersibility in water. Particle size distribution analysis by dynamic light scattering revealed that the particle size of the octadecyl-modified ND in chloroform, a non-polar solvent, was ca. 20 nm. Thus, the present method should be useful for fabricating NDs that can be dispersed in non-polar organic solvents and should facilitate the expansion of the application fields of ND.

Primary challenges in electrochemical CO2 reduction lie with its product selectivity and competitive hydrogen evolution reaction (HER). Therefore, selective CO2 reduction with less hydrogen evolution or without any hydrogen evolution is very essential for industrial interests. In this study, we report a selective electrochemical CO2 reduction at a boron-doped diamond electrode modified with Cu nanoparticles in ionic liquid. In addition to the improved product selectivity, control of the competitive HER was also achieved in this work.

Titanium dioxide (TiO2) has been widely used as a catalyst material in different applications such as photocatalysis, solar cells, supercapacitor, and hydrogen production, due to its better chemical stability, high redox potential, wide band gap, and eco-friendly nature. In this work TiO2 thin films have been deposited onto both glass and silicon substrates by the atmospheric pressure plasma jet (APPJ) technique. The structure and morphological properties of TiO2 thin films are studied using different characterization techniques like X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and field emission scanning electron microscopy. XRD study reveals the bronze-phase of TiO2. The XPS study shows the presence of Ti, O, C, and N elements. The FE-SEM study shows the substrate surface is well covered with a nearly round shaped grain of different size. The optical study shows that all the deposited TiO2 thin films exhibit strong absorption in the ultraviolet region. The oleic acid photocatalytic decomposition study demonstrates that the water contact angle decreased from 80.22 to 27.20° under ultraviolet illumination using a TiO2 photocatalyst.

Boron-doped diamond powder (BDDP) was prepared using various sizes of diamond powder (DP) core (300–2600 nm), and the electrochemical properties of a screen-printed electrode obtained using the BDD...

Diamond synthesis and its morphology by in-liquid plasma chemical vapor deposition (CVD) method are investigated in this study. Diamond films were grown on Si substrates from mixed alcohol solution. Very high growth rate of 170 μm/h was achieved by this method. Microcrystalline and nanocrystalline diamond films were formed in different conditions. In the case of microcrystalline film, the shapes of diamond grains depend on the location in the film. All morphological differences in this study can be explained by the same mechanism of conventional gas phase CVD method. It means diamond morphology by in-liquid plasma CVD method can be controlled by process parameters as well as gas phase CVD method.

The electrochemical properties of screen-printed diamond electrodes with various insulating polyester (PES) resin binder/boron-doped diamond powder (BDDP) ratios were investigated for high sensitivity electrochemical detection. For PES/BDDP weight ratios in the range of 0.3-0.5, the BDDP-printed electrodes exhibited cyclic voltammetry (CV) characteristics for Fe(CN)6(3-/4-) that are typical of a planar electrode, whereas microelectrode-like characteristics with sigmoidal CV curves were observed for PES/BDDP ratios of 1.0-2.0. Cu elemental mapping images of copper-electrodeposited BDDP-printed electrodes indicated the formation of island structures with conductive BDDP domains surrounded by an insulating PES matrix for large PES/BDDP ratios. The electrochemical detection of ascorbic acid (AA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) was also investigated using polycrystalline BDD thin-film and BDDP-printed electrodes (PES/BDDP ratio = 0.3 and 1.0). As a result, the signal-to-background (S/B) ratios for the voltammetric detection of AA and 8-OHdG were in the order BDDP-printed electrode (PES/BDDP = 1.0)BDDP-printed electrode (PES/BDDP = 0.3)polycrystalline BDD thin film electrode, based on the large faradaic current with respect to the background current. Therefore, the BDDP-printed electrode with a large insulating binder/BDDP ratio has the potential for use as a disposable electrode for electrochemical detection. The electrode is cheaper, lighter and more sensitive than conventional BDD electrodes.

Alkyl (oligo)glucosides (AOG) are known to be environmentally compatible amphiphiles whose commercial applicability should be broadened. The present paper describes the preparation of molecular assemblies of industrially produced AOG, which is a mixture composed of different length of alkyl chains (C9-C12) with oligoglucoside moiety with a few (1-3) of glucose units. It was also described that regulation of the dispersibility of the molecular assemblies prepared by diol-boron complexation between the sugar moiety on AOG and boric acid in a dispersion medium. The molecular assembly of AOG was successfully formed by mixing AOG and cholesterols (CH). When using a suitable amount of CH (20-40 mol% with respect to AOG), the molecular assembly formed a vesicle structure. The dispersion ability of the resulting vesicle was dependent on both the boric acid concentration and pH of the dispersion medium. The light-scattering and ζ-potential measurements revealed that high concentrations (≥10 mM) of boric acid improved dispersibility the vesicles. In contrast, the vesicle agglomerated at low concentrations of boric acid (1-7.5 mM). In the absence of boric acid in dispersion medium, the vesicles were completely agglomerated. The optimum pH range for vesicle dispersion was found to be from neutral to basic (7.4-10.1). The (11)B NMR study revealed that borate ester formation occurred between boric acid and the diol of the sugar moiety on AOG vesicle. The present data suggest that borate ester formation that occurred on the surface of the vesicle provided negative charge to the vesicles, contributing to their dispersion via repulsive forces.

Understanding the fundamentals of photoelectrocatalytic (PEC) biomolecular oxidation benefits the development of next-generation PEC biosensors. In this work, single-step electrospun titanium-di-oxide–gold (TiO2–Au) hybrid nanofibers (HNF) are reported as being a potential candidate for PEC glutathione (GSH) bioanalysis. The chemical environment of TiO2 and TiO2–Au HNFs were studied with X-ray photoelectron spectroscopy and found to have a strong electronic interaction between TiO2 and the Au nanoparticles (NPs). The PEC measurements revealed that the intramolecular backbone hydrogen bonding of GSH molecules predominantly contributes highly active Au–GSH bio-nano interfaces, which facilitate the PEC oxidation rate of GSH and thus enhance the photocurrent. Furthermore, the Au NPs present act as auxiliary electron transport channels resulting in enhanced charge collection at the external circuit. As a result, the TiO2–Au electrode generated a two-fold higher photocurrent density of ∼84.4 μA cm−2 in the presence of 0.5 mM GSH, where the pristine TiO2 NFs displayed only a negligible influence. Likewise, the TiO2–Au HNF electrode showed a higher sensitivity of 0.002 mM and a wide linear detection range between 0.022 mM and 0.7 mM, with a superior selectivity towards GSH bioanalysis over ascorbic acid and glucose at −0.33 V (versus silver/silver chloride) than that obtained with pristine TiO2. The implications of these findings towards the development of a next-generation PEC biosensor are discussed.

1,2-Dipalmitoryl-sn-glycero-3-(3-boronopropyl-N,N-dimethylaminium) (DPBA), a lipid which specifically binds to diol compounds through the boronic acid moiety, was synthesized. Cryo-TEM observation revealed that DPBA formed unilamellar vesicles in an aqueous environment. Thermotropic phase-transition temperature of DPBA was increased in response to addition of either diols or phosphatidylcholine, indicating that DPBA has both diol responsivity and is characteristic as a reversed-head lipid.

We prepared pH-sensitive anionic liposomes composed solely of anionic bilayer membrane components that were designed to promote efficient release of entrapped agents in response to acidic pH. The pH-sensitive anionic liposomes showed high dispersion stability at neutral pH, but the fluidity of the bilayer membrane was enhanced in an acidic environment. These liposomes were rather simple and were composed of dimyristoylphosphatidylcholine (DMPC), an anionic bilayer membrane component, and polyoxyethylene sorbitan monostearate (Tween 80). In particular, the present pH-sensitive anionic liposomes showed higher temporal stability than those of conventional DMPC/DPPC liposomes. We found that pHsensitive properties strongly depended on the molecular structure, pKa value, and amount of an incorporated anionic bilayer membrane component, such as sodium oleate (SO), dimyristoylphosphatidylserine (DMPS), or sodium β-sitosterol sulfate (SS). These results provide an opportunity to manipulate liposomal stability in a pH-dependent manner, which could lead to the formulation of a high performance drug delivery system (DDS).

We report a simple room-temperature synthesis route for increasing the reactivity of a TiO2 photocatalyst using a solution plasma process (SPP). Hydrogen radicals generated from the SPP chamber interact with the TiO2 photocatalyst feedstock, transforming its crystalline phase and introducing oxygen vacancy defects. In this work, we examined a pure anatase TiO2 as a model feedstock because of its photocatalytic attributes and well-characterized properties. After the SPP treatment, the pure anatase crystalline phase was transformed to an anatase/brookite heterocrystalline phase with oxygen vacancies. Furthermore, the SPP treatment promoted the absorption of both UV and visible light by TiO2. As a result, TiO2 treated by the SPP for 3 h showed a high gaseous photocatalytic performance (91.1%) for acetaldehyde degradation to CO2 compared with the activity of untreated TiO2 (51%). The SPP-treated TiO2 was also more active than nitrogen-doped TiO2 driven by visible light (66%). The overall photocatalytic performance was related to the SPP treatment time. The SPP technique could be used to enhance the activity of readily available feedstocks with a short processing time. These results demonstrate the potential of this method for modifying narrow-band gap metal oxides, metal sulfides, and polymer composite-based catalyst materials. The modifications of these materials are not limited to photocatalysts and could be used in a wide range of energy and environment-based applications.