RSC Advances

Xie, Wenyuan; Wang, Honglei; Tong, Yen Wah; Sankarakumar, Niranjani; Yin, Ming; Wu, Defeng; Duan, Xiaoli

doi: 10.1039/c9ra02805fpmid: 35530613

A surface imprinting method is presented herein for the development of a highly selective yet highly permeable molecularly imprinted membrane for protein separation and purification. The resultant protein imprinted membrane was shown to exhibit great potential for the efficient separation of the template protein from a binary mixture and a cell lysate solution, while maintaining high transport flux for complementary molecules. Bovine Serum Albumin (BSA) and Lysozyme (Lys) were individually immobilized on a cellulose acetate membrane as template molecules. In situ surface crosslinking polymerization was then used for protein imprinting on the membrane for a controlled duration. Both membranes showed high adsorption capacity towards template proteins in the competitive batch rebinding tests. In addition, the adsorption capacity could be greatly enhanced in a continuous permeation procedure, where the resultant membrane specifically adsorbed the template protein for more than 40 h. Moreover, this is the first report of purification of a specific protein from the cell broth mixture using a molecularly imprinted membrane. The protein imprinted membrane enables the transport of multiple non-template proteins with high permeation rate in a complex system, thus opening the way for high efficiency protein separation at a low cost for the industry.

Zhu, Suhong; Ji, Tao; Yang, Bin; Yang, Zhengxian

doi: 10.1039/c9ra03329gpmid: 35530620

A new shape-stabilized phase change material based on polyethylene glycol (PEG) and surface-modified layered double hydroxides (LDHs) was prepared by a solution impregnation method. PEG enabled thermal energy storage and release as a phase change material; 3-aminopropyl triethoxysilane (KH550) was used to modify the surface of LDHs (KH-LDHs) which then acted as a carrier to keep the solid form of the molten PEG at high temperature. The maximum weight percentage of PEG confined in the PEG/KH-LDHs composite was 55%. The detailed structures, thermal properties and UV absorption of the composite were characterized systematically by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermal gravimetric (TG) analysis and UV-vis absorption spectra. Results show that the PEG/KH-LDH composite has a suitable phase change temperature, considerable enthalpy, and good thermal stability as well as remarkable ultraviolet absorption ability. As a new shape-stabilized phase change material, the PEG/KH-LDH composite is expected to contribute to the effort of searching effective measures for thermal management of building and pavement materials.

Kumar, Kunal; Abe, Daisuke; Komori-Orisaku, Keiko; Stefańczyk, Olaf; Nakabayashi, Koji; Shakirova, Julia R.; Tunik, Sergey P.; Ohkoshi, Shin-ichi

doi: 10.1039/c9ra03276bpmid: 35530587

Self-assembly of β-diketonate (Htta = thenoyl(trifluoro)acetone) and 4,4′-azopyridine (Azo-py) with neodymium(iii) ions in the presence of methanol resulted in the formation of mononuclear complex [NdIII(TTA)3(MeOH)2]·0.5Azo-py (A) in which two asymmetric units are linked by Azo-py through hydrogen bonding via methanol. A reveals near-infrared emission (NIR) centred at about 895 and 1056 nm, in the 10–370 K temperature range, originating from the two emissive transitions on Nd(iii) from 4F3/2 to 4I9/2 and 4I11/2 levels, respectively. Furthermore, the NIR luminescence intensity of A at room temperature augments two times upon thermal elimination of one coordinated methanol molecule. The thermally activated A exhibits single centre ratiometric thermometer behaviour in a wide temperature range from 10 to 300 K. Moreover, fluorescence properties of A were compared to another mononuclear complex [NdIII(TTA)3(4-OHpy)(H2O)] (B). Assembly A also exhibits field-induced slow magnetic relaxation properties with an energy barrier of ΔE/kB = 19.7(7) K and an attempt time of relaxation, τ0 = 3.7(8) × 10−7 s for fresh sample A, and ΔE/kB = 27.3 K and τ0 = 8.5(0) × 10−8 for assembly A after thermal treatment at 370 K.

da Conceição, Leyvison Rafael V.; Reis, Cristiano E. R.; de Lima, Rosemar; Cortez, Daniela V.; de Castro, Heizir F.

doi: 10.1039/c9ra04300dpmid: 35530583

Heteropolyacids (HPA) with Keggin structures, such as H3PMo12O40 (H3PMo), have been described as efficient catalysts in trans/esterification reactions due to their tolerance to water and free fatty acids contents, with particularly well-suited characteristics of high proton mobility and stability. The versatile array of HPA is considerably increased when such catalysts are supported onto solid matrices. In this sense, Al2O3 was assessed as support for H3PMo to be used in trans/esterification reactions to produce biodiesel from high-acid feedstocks. The catalyst structure was characterized and applied on trans/esterification reaction of acid oils using ethanol as acyl acceptor. A face centered composite design was employed to conduct the experimental design and results analysis, taking macaw palm oil as study model. The process achieved an optimum level of 99.8% ester content and 4.1 mm2 s−1 viscosity under the following reaction conditions: 190 °C reaction temperature, 50 : 1 ethanol-to-oil molar ratio and 13.0% catalyst concentration. Other tested feedstocks (fungal single cell oil and residual frying oil) were also tested promoting satisfactory results, though the parameters were found to be slightly outside the limits set by the USA (ASTM D6715) standard. The H3PMo/Al2O3 catalyst presented good regeneration and can be reused for up to four reaction cycles and requires lower ethanol-to-oil ratio, temperature, and catalyst concentration in comparison with other data from the literature.

Zhang, Zheng; Yang, Ge; Zhou, Chuanzhen; Chung, Ching-Chang; Hany, Ibrahim

doi: 10.1039/c9ra04045epmid: 35530628

In this work, we explored the possibility of using Cs2AgBiBr6, a double perovskite crystal, for radiation detection. Cs2AgBiBr6 crystals were grown using the solution growth technique. The resistivity of the as-grown Cs2AgBiBr6 crystal is larger than 1010 Ω cm, which is high enough to ensure low leakage current for fabrication of semiconductor radiation detectors. Using the temperature-dependent resistivity measurements, we estimated that the Fermi level is at 0.788 eV above the valence band and the material is a p-type semiconductor. From the low-temperature cathodoluminescence measurements, two near band gap energies at 1.917 eV and 2.054 eV were revealed.

Guo, Xinyu; Zhao, Rui; Zhang, Jia; Du, Ying-Jie; Yang, Lu-Guang; Chen, Luoyun; Pang, Sen; Xu, Yong; Zhang, Zhenhua; Wu, Xuemin

doi: 10.1039/c9ra03762dpmid: 35530573

1-Methylcyclopropene (1-MCP) is an important gaseous plant growth regulator. For its application as a gaseous pesticide, the plants with 1-MCP α-cyclodextrin microcapsule granules need to be enclosed in a sealed chamber. To provide a new spray formulation of 1-MCP for open environment application, herein, a novel 1-MCP microcapsule oil dispersion (1-MCP/MCOD) was prepared and characterized. It was found that 1-MCP could stay at higher concentrations for more than 36 hours during the controlled release experiment, and the SEM experiment showed good deposition of the 1-MCP/MCOD spray solution. In addition, the apple harvest application experiments showed that 1-MCP/MCOD could effectively prevent fruit drop at 3 μL L−1 in an open environment. These results not only supply a new 1-MCP/MCOD kind of formulation for the flexible application of the 1-MCP gas in an open environment, but also show that this microcapsule oil dispersion formulation has significant potential in gaseous pesticide applications.

Xie, Chunsheng; Wei, Shoulian; Chen, Dan; Lan, Wenying; Yan, Zijun; Wang, Zhenxing

doi: 10.1039/c9ra03859kpmid: 35530598

In this work, a magnetic ion imprinted polymer (MIIP) with specific recognition capability toward cadmium was prepared by a sol–gel method using waste beer yeast, which is a macromolecule biomass, as a functional monomer. The obtained Cd(ii)-MIIP was characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and adsorption experiments. Then, a MIIP adsorbent based magnetic solid phase extraction (MSPE)-graphite furnace atomic absorption (GFAA) method was established to analyze the cadmium content in food and environmental samples. The maximum cadmium adsorption capacities by the MIIP and magnetic non-imprinted polymer (MNIP) were 62.74 and 32.38 mg g−1, respectively. The absorption by the MIIP was fitted using a pseudo-second-order kinetic model. The Cd(ii)-MIIP demonstrated superior absorption capability for selective removal cadmium. The recovery rate of the MIIP was 90.7% after four adsorption–desorption cycles. The calculated Cd(ii) detection limit (S/N = 3) was 0.18 μg L−1 with the relative standard deviation (RSD) equal to ∼3.5% for 10 μg L−1 of Cd(ii) standard solution. Our proposed method was successfully used in detecting Cd(ii) in aqueous samples. The results obtained in this work suggest that the Cd(ii)-MIIPs might be promising adsorbents to remove harmful cadmium ions from aqueous samples.

Freichel, Tanja; Laaf, Dominic; Hoffmann, Miriam; Konietzny, Patrick B.; Heine, Viktoria; Wawrzinek, Robert; Rademacher, Christoph; Snyder, Nicole L.; Elling, Lothar; Hartmann, Laura

doi: 10.1039/c9ra05497apmid: 35530592

In this work, we present a bottom-up approach for the synthesis of lactose-functionalized glycomacromolecules and glycofunctionalized liposomes and apply these compounds to investigate their effects of multivalent presentation on binding to galectin-3. Step-wise assembly of tailor-made building blocks on solid supports was used to synthesize a series of oligo(amidoamine) scaffolds that were further conjugated to lactose via copper catalyzed 1,3-dipolar cycloaddition. Binding studies with galectin-3 revealed affinities in the micromolar range that increased with increasing carbohydrate valency, and decreased with increasing size and linker flexibility. To further explore their multivalency, selected glycomacromolecules were conjugated to lipids and used in liposomal formulations. Binding studies show a further increase in binding in nanomolar ranges in dependence of both ligand structure and liposomal presentation, demonstrating the power of combining the two approaches.

Silakaew, Kanyapak; Thongbai, Prasit

doi: 10.1039/c9ra04933apmid: 35530602

The effects of different BaTiO3 sizes (≈100 nm (nBT) and 0.5–1.0 μm (μBT)) on the dielectric and electrical properties of multiwall carbon nanotube (CNT)-BT/poly(vinylidene fluoride) (PVDF) composites are investigated. The fabricated three-phase composites using 20 vol% BT with various CNT volume fractions (fCNT) are systematically characterized. The dielectric permittivity (ε′) of the CNT-nBT/PVDF and CNT-μBT/PVDF composites rapidly increases when fCNT > 0.015 and fCNT > 0.017, respectively. The former is accompanied by the dramatic increase in the loss tangent (tan δ) and conductivity (σ), but surprisingly, not for the latter. At 103 Hz, the low tan δ and σ values of the CNT-μBT/PVDF composite are about 0.06 and 6.82 × 10−9 S cm−1, while its ε′ value is greatly enhanced (≈154.6). The variation of the dielectric permittivity with fCNT for both composite systems follows the percolation model with percolation thresholds of fc = 0.018 and fc = 0.02, respectively. With further increasing fCNT to 0.02, ε′ is greatly increased to 253.8, while tan δ ≤ 0.1. Without μBT particles, the ε′ and tan δ values of the CNT/PVDF composite with fCNT = 0.02 are as high as ≈240 and >103, respectively. Greatly enhanced dielectric properties are described in detail.

Ebadi, Mojgan; Zolfaghari, Mohammad Reza; Aghaei, Seyyed Soheil; Zargar, Mohsen; Shafiei, Morvarid; Zahiri, Hossein Shahbani; Noghabi, Kambiz Akbari

doi: 10.1039/c9ra03962gpmid: 35530580

Cyanobacteria, as one of the largest groups of phototrophic bacteria, have a high potential as an excellent source of fine chemicals and bioactive compounds, including lipid-like compounds, amino acid derivatives, proteins, and pigments. This study aimed to synthesize ZnO nanoparticles using the cell extract of the cyanobacterium Nostoc sp. EA03 (CEN-ZnO NPs) through a rapid and eco-friendly approach. The biosynthesized nanoparticles, CEN-ZnO NPs, were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), zeta potential measurement, differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA), FTIR, SEM, TEM, and EDX spectroscopy. The UV-Vis spectrum showed an absorption peak at 370 nm. The star-shaped CEN-ZnO NPs, as observed in the TEM and SEM images, had an average diameter of 50–80 nm. MIC and MBC values for E. coli, P. aeruginosa and S. aureus, were determined to be, respectively, 2000, 2000, and 64 μg ml−1, and 2500, 2500 and 128 μg ml−1. Further analysis through confocal laser scanning microscopy (CLSM) provided the observable confirmation that the CEN-ZnO NPs stunted the bacterial growth, preventing the formation of exopolysaccharides. The AFM analysis of surface topography of bacterial biofilm samples treated with CEN-ZnO NPs showed a rugged topography in some parts of the biofilm surface, indicating the destruction of biofilms. In contrast, in the untreated control samples, the structured biofilms were flat and prominent. MTT assay indicated that CEN-ZnO NPs had less cytotoxicity on the MRC-5 lung fibroblast cells compared with the cancerous treated A549 cells. As the concentration of the CEN-ZnO NPs increased, the amount of ROS produced in the tested bacterial strains also increased. Analyzing the data obtained from flow cytometry showed that the higher concentrations of CEN-ZnO NPs lead to a reduction in the viability of P. aeruginosa PAO1, E. coli and S. aureus. The biosynthesized ZnO nanoparticles using Nostoc cell extracts exhibited different attributes, inspiring enough to be considered for further investigation.