Optimization of lipase-catalyzed synthesis of sorbitan acrylate using response surface methodology

In this study, we have synthesized sorbitan acrylate through response surface methodology, using sorbitan and vinyl acrylate that catalyze immobilized lipase. In order to optimize the enzymatic synthesis of the sorbitan acrylate, we applied response surface techniques to determine the effects of five-level-four-factors and their reciprocal interactions with the biosynthesis of sorbitan acrylate. Our statistical model predicted that the highest conversion yield of sorbitan acrylate would be approx 100%, under the following optimized reaction conditions: a reaction temperature of 40.1 degrees C, a reaction time of 237.4 min, an enzyme concentration of 8%, and a 4.49:1 acyl donor/acceptor molar ratio. Using these optimal conditions in three independent replicates, the conversion yield reached 97.6+/-1.3%.     

Self-assembly of chemically linked rod-disc mesogenic liquid crystals

A series of new molecular discs (RDn, here n is the number of carbon atoms between the rod and disc mesogens) was synthesized via the chemical attachment of six cyanobiphenyl calamitic (rod) mesogens (R) linked to the triphenyl discotic (disc) mesogen (D) with a series of six alkyl chain linkages (n = 6-12). In this study, phase structures, transitions, and liquid crystalline (LC) behavior of the RD12 compound with 12 carbon atoms in each alkyl chain linkage between the rod and disc mesogens were investigated. Differential scanning calorimetry, polarized light microscopy, wide-angle X-ray diffraction (WAXD), and selected area electron diffraction (SAED) allowed us to identify three ordered phases below the isotropization temperature: nematic (N) LC and K1 and K2 crystalline phases. On the basis of the structural results obtained via 2D WAXD experiments on oriented samples and SAED experiments on single crystals, the K1 crystalline unit cell was determined to be triclinic with the dimensions of a = 1.36 nm, b = 1.45 nm, c = 2.11 nm, alpha = 85 degrees, beta = 100 degrees, and gamma = 50 degrees. The K2 phase was metastable with respect to the K1 phase. It also possessed a triclinic unit cell with a = 1.40 nm, b = 1.51 nm, c = 1.92 nm, alpha = 87 degrees, beta = 117 degrees, and gamma = 62 degrees. Molecular packing models for the crystalline phases were proposed on the basis of the diffraction results. In the whole range of ordered structures, it was found that RD12 molecular discs are intercalated. Both triphenyl discotic mesogens and cyanobiphenyl calamitic mesogens are completely interdigitated.     

Sustainable biorefinery processes using renewable deep eutectic solvents

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Effect of Penetration Enhancers on Toenail Delivery of Efinaconazole from Hydroalcoholic Preparations

The incorporation of permeation enhancers in topical preparations has been recognized as a simple and valuable approach to improve the penetration of antifungal agents into toenails. In this study, to improve the toenail delivery of efinaconazole (EFN), a triazole derivative for onychomycosis treatment, topical solutions containing different penetration enhancers were designed, and the permeation profiles were evaluated using bovine hoof models. In an in vitro permeation study in a Franz diffusion cell, hydroalcoholic solutions (HSs) containing lipophilic enhancers, particularly prepared with propylene glycol dicaprylocaprate (Labrafac PG), had 41% higher penetration than the HS base. Moreover, the combination of hydroxypropyl-β-cyclodextrin with Labrafac PG further facilitated the penetration of EFN across the hoof membrane. In addition, this novel topical solution prepared with both lipophilic and hydrophilic enhancers was physicochemically stable, with no drug degradation under ambient conditions (25 °C, for 10 months). Therefore, this HS system can be a promising tool for enhancing the toenail permeability and therapeutic efficacy of EFN.     

Tuning Local Coordination Environments of Manganese Single-Atom Nanozymes with Multi-Enzyme Properties for Selective Colorimetric Biosensing

Single-atom nanozymes (SAzymes) are promising in next-generation nanozymes, nevertheless, how to rationally modulate the microenvironment of SAzymes with controllable multi-enzyme properties is still challenging. Herein, we systematically investigate the relationship between atomic configuration and multi-enzymatic performances. The constructed Mn_SA−N₃-coordinated SAzymes (Mn_SA−N₃−C) exhibits much more remarkable oxidase-, peroxidase-, and glutathione oxidase-like activities than that of Mn_SA−N₄−C. Based on experimental and theoretical results, these multi-enzyme-like behaviors are highly dependent on the coordination number of single atomic Mn sites by local charge polarization. As a consequence, a series of colorimetric biosensing platforms based on Mn_SA−N₃−C SAzymes is successfully built for specific recognition of biological molecules. These findings provide atomic-level insight into the microenvironment of nanozymes, promoting rational design of other demanding biocatalysts.     

A Highly Sensitive Amperometric Galactose Biosensor Based on Graphene-doped Sol-gel-derived Titania-Nafion Composite Films

A highly sensitive amperometric galactose biosensor was developed by encapsulating galactose oxidase within the graphene-doped sol-gel titania-Nafion composite film on platinized glassy carbon electrode. Due to the combined electrocatalytic activity of graphene and Pt NPs on the electrode towards hydrogen peroxide as well as the mesoporous nature of the titania-Nafion composite, the present galactose biosensor exhibited relatively fast response time under 2 s, high sensitivity of 40.6 mAM⁻¹cm⁻², and wide dynamic range over three orders of magnitude with a detection limit of 3.78×10⁻⁶ M (S/N=3). In addition, the biocompatible composite in the biosensor secures excellent long-term stability.     

Radiocatalytic H2 production with gamma-irradiation and TiO2 catalysts

The radioactive concentrations of radionuclides were measured in the soil and groundwater below the 12 GeV proton beam-line tunnel at KEK. Various long-lived radionuclides, (⁷Be, ²²Na, ⁴⁶Sc, ⁵⁴Mn, ⁶⁰Co, ¹³⁴Cs, ¹⁵²Eu and ¹⁵⁴Eu) were observed in the soil samples by -ray spectra measurements, and ³H was also detected by liquid scintillation counting. On the other hand, ³H, ²²Na and ⁵⁴Mn, which were leached from the soil were measured in the groundwater below the EP2 beam line. ³H and ²²Na were also found in slight amounts in groundwater collected in a well dug beside the East Counter Hall. From a comparison with the radioactive concentration in soil and groundwater, the order of the leaching percentages were ³H>²²Na>⁵⁴Mn. This tendency was in agreement with an experimental result of the RI laboratory.     

Integrated chemical sensor array platform based on a light emitting diode, xerogel-derived sensor elements, and high-speed pin printing

We report a new, solid-state, integrated optical array sensor platform. By using pin printing technology in concert with sol-gel-processing methods, we form discrete xerogel-based microsensor elements that are on the order of 100 μm in diameter and 1 μm thick directly on the face of a light emitting diode (LED). The LED serves as the light source to excite chemically responsive luminophores sequestered within the doped xerogel microsensors and the analyte-dependent emission from within the doped xerogel is detected with a charge coupled device (CCD). We overcome the problem of background illumination from the LED reaching the CCD and the associated biasing that results by coating the LED first with a thin layer of blue paint. The thin paint layer serves as an optical filter, knocking out the LEDs red-edge spectral tail. The problem of the spatially-dependent fluence across the LED face is solved entirely by performing ratiometric measurements. We illustrate the performance of the new sensor scheme by forming an array of 100 discrete O₂-responsive sensing elements on the face of a single LED. The combination of pin printing with an integrated sensor and light source platform results in a rapid method of forming (∼1 s per sensor element) reusable sensor arrays. The entire sensor array can be calibrated using just one sensor element. Array-to-array reproducibly is <8%. Arrays can be formed using single or multiple pins with indistinguishable analytical performance.