scholarly journals Green Synthesized Magnetic Nanoparticles as Effective Nanosupport for the Immobilization of Lipase: Application for the Synthesis of Lipophenols

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 458
Author(s):  
Renia Fotiadou ◽  
Alexandra V. Chatzikonstantinou ◽  
Mohamed Amen Hammami ◽  
Nikolaos Chalmpes ◽  
Dimitrios Moschovas ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Immobilized Lipase ◽  
Aqueous Media ◽  
Spherical Shape ◽  
Fatty Acid Esters ◽  
Thermomyces Lanuginosus ◽  
Omega 3 ◽  
Factors Affecting ◽  
X Ray

In this work, hybrid zinc oxide–iron oxide (ZnOFe) magnetic nanoparticles were synthesized employing Olea europaea leaf aqueous extract as a reducing/chelating and capping medium. The resulting magnetic nanoparticles were characterized by basic spectroscopic and microscopic techniques, namely, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fourier-transform infrared (FTIR) and atomic force microscopy (AFM), exhibiting a spherical shape, average size of 15–17 nm, and a functionalized surface. Lipase from Thermomyces lanuginosus (TLL) was efficiently immobilized on the surface of ZnOFe nanoparticles through physical absorption. The activity of immobilized lipase was found to directly depend on the enzyme to support the mass ratio, and also demonstrated improved pH and temperature activity range compared to free lipase. Furthermore, the novel magnetic nanobiocatalyst (ZnOFe-TLL) was applied to the preparation of hydroxytyrosyl fatty acid esters, including derivatives with omega-3 fatty acids, in non-aqueous media. Conversion yields up to 90% were observed in non-polar solvents, including hydrophobic ionic liquids. Different factors affecting the biocatalyst performance were studied. ZnOFe-TLL was reutilized for eight subsequent cycles, exhibiting 90% remaining esterification activity (720 h of total operation at 50 °C). The green synthesized magnetic nanoparticles, reported here for the first time, are excellent candidates as nanosupports for the immobilization of enzymes with industrial interest, giving rise to nanobiocatalysts with elevated features.

scholarly journals A Sustainable Biomineralization Approach for the Synthesis of Highly Fluorescent Ultra-Small Pt Nanoclusters

Biosensors ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 128 ◽  
Author(s):  
Rajkamal Balu ◽  
Robert Knott ◽  
Christopher M. Elvin ◽  
Anita J. Hill ◽  
Namita R. Choudhury ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Photoelectron Spectroscopy ◽  
Photophysical Properties ◽  
Conformational Dynamics ◽  
Aqueous Media ◽  
Intrinsically Disordered Protein ◽  
X Ray ◽  
Pt Nanoclusters ◽  
Intrinsically Disordered ◽  
Green Fluorescent

Herein we report the first example of a facile biomineralization process to produce ultra-small-sized highly fluorescent aqueous dispersions of platinum noble metal quantum clusters (Pt-NMQCs) using a multi-stimulus responsive, biomimetic intrinsically disordered protein (IDP), Rec1-resilin. We demonstrate that Rec1-resilin acts concurrently as the host, reducing agent, and stabilizer of the blue-green fluorescent Pt-NMQCs once they are being formed. The photophysical properties, quantum yield, and fluorescence lifetime measurements of the synthesized Pt-NMQCs were examined using UV-Vis and fluorescence spectroscopy. The oxidation state of the Pt-NMQCs was quantitatively analyzed using X-ray photoelectron spectroscopy. Both a small angle X-ray scattering technique and a modeling approach have been attempted to present a detailed understanding of the structure and conformational dynamics of Rec1-resilin as an IDP during the formation of the Pt-NMQCs. It has been demonstrated that the green fluorescent Pt-NMQCs exhibit a high quantum yield of ~7.0% and a lifetime of ~9.5 ns in aqueous media. The change in photoluminescence properties due to the inter-dot interactions between proximal dots and aggregation of the Pt-NMQCs by evaporation was also measured spectroscopically and discussed.

scholarly journals Microwave synthesis of high-quality and uniform 4 nm ZnFe2O4 nanocrystals for application in energy storage and nanomagnetics

2016 ◽  
Vol 7 ◽  
pp. 1350-1360 ◽  
Author(s):  
Christian Suchomski ◽  
Ben Breitung ◽  
Ralf Witte ◽  
Michael Knapp ◽  
Sondes Bauer ◽  
...  
Keyword(s):  
Energy Storage ◽  
Photoelectron Spectroscopy ◽  
Zinc Ferrite ◽  
Sol Gel ◽  
High Capacity ◽  
Spherical Shape ◽  
Freezing Temperature ◽  
Ex Situ ◽  
Edge Structure ◽  
X Ray

Magnetic nanocrystals with a narrow size distribution hold promise for many applications in different areas ranging from biomedicine to electronics and energy storage. Herein, the microwave-assisted sol–gel synthesis and thorough characterization of size-monodisperse zinc ferrite nanoparticles of spherical shape is reported. X-ray diffraction, 57Fe Mössbauer spectroscopy and X-ray photoelectron spectroscopy all show that the material is both chemically and phase-pure and adopts a partially inverted spinel structure with Fe3+ ions residing on tetrahedral and octahedral sites according to (Zn0.32Fe0.68)tet[Zn0.68Fe1.32]octO4±δ. Electron microscopy and direct-current magnetometry confirm the size uniformity of the nanocrystals, while frequency-dependent alternating-current magnetic susceptibility measurements indicate the presence of a superspin glass state with a freezing temperature of about 22 K. Furthermore, as demonstrated by galvanostatic charge–discharge tests and ex situ X-ray absorption near edge structure spectroscopy, the as-prepared zinc ferrite nanocrystals can be used as a high-capacity anode material for Li-ion batteries, showing little capacity fade – after activation – over hundreds of cycles. Overall, in addition to the good material characteristics, it is remarkable that the microwave-based synthetic route is simple, easily reproducible and scalable.

scholarly journals Novel Ecogenic Plasmonic Biohybrids as Multifunctional Bioactive Coatings

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 659 ◽  
Author(s):  
Marcela Elisabeta Barbinta-Patrascu ◽  
Camelia Ungureanu ◽  
Nicoleta Badea ◽  
Mihaela Bacalum ◽  
Andrada Lazea-Stoyanova ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Spherical Shape ◽  
Common Garden ◽  
Amaranthus Retroflexus ◽  
Mentha Piperita ◽  
Bioactive Coatings ◽  
X Ray ◽  
Force Microscopy ◽  
Green Approach ◽  
Atomic Force

The objective of the present study is the valorization of natural resources and the recycling of vegetal wastes by converting them into novel plasmonic bio-active hybrids. Thus, a “green” approach was used to design pectin-coated bio-nanosilver. Silver nanoparticles were generated from two common garden herbs (Mentha piperita and Amaranthus retroflexus), and pectin was extracted from lemon peels. The samples were characterized by the following methods: Ultraviolet–visible (UV-Vis) absorption spectroscopy, Fourier Transform Infrared (FT-IR), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), dynamic light scattering (DLS), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM)–Energy-dispersive X-ray Spectroscopy (EDX), and zeta potential measurements. Microscopic investigations revealed the spherical shape and the nano-scale size of the prepared biohybrids. Their bioperformances were checked in terms of antioxidant and antibacterial activity. The developed plasmonic materials exhibited a strong ability to scavenge short-life (96.1% ÷ 98.7%) and long-life (39.1% ÷ 91%) free radicals. Microbiological analyses demonstrated an impressive antibacterial effectiveness of pectin-based hybrids against Escherichia coli. The results are promising, and the obtained biomaterials could be used in many bio-applications, especially as antioxidant and antimicrobial biocoatings.

scholarly journals Soil Pollution Characteristics and Microbial Responses in a Vertical Profile with Long-Term Tannery Sludge Contamination in Hebei, China

2019 ◽  
Vol 16 (4) ◽  
pp. 563 ◽  
Author(s):  
Xiangke Kong ◽  
Chunhui Li ◽  
Ping Wang ◽  
Guoxin Huang ◽  
Zhitao Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Soil Profile ◽  
Stable State ◽  
Chemical Properties ◽  
Tannery Sludge ◽  
Factors Affecting ◽  
X Ray ◽  
Degrading Bacteria ◽  
Microbial Responses

An investigation was made into the effects of tannery sludge on soil chemical properties and microbial communities in a typical soil profile with long-term tannery sludge contamination, North China. The results showed that trivalent chromium (Cr(III)), ammonium, organic nitrogen, salinity and sulfide were the predominant contaminants in tannery sludge. Although the tannery sludge contained high chromium (Cr, 3,0970 mg/kg), the proportion of mobile Cr forms (exchangeable plus carbonate-bound fraction) only accounted for 1.32%. The X-ray diffraction and X-ray photoelectron spectroscopy results further demonstrated that the Cr existed in a stable state of oxides and iron oxides. The alkaline loam soil had a significant retardation effect on the migration of salinity, ammonium, Cr(III) and sulfide, and the accumulation of these contaminants occurred in soils (0–40 cm). A good correlation (R2 = 0.959) was observed between total organic carbon (TOC) and Cr(III) in the soil profile, indicating that the dissolved organic matter from sludge leachate promoted the vertical mobility of Cr(III) via forming Cr(III)-organic complexes. The halotolerant bacteria (Halomonas and Tepidimicrobium) and organic degrading bacteria (Flavobacteriaceae, Tepidimicrobium and Balneola) became the dominant microflora in the soil profile. High contents of salinity, Cr and nitrogen were the main environmental factors affecting the abundance of indigenous microorganisms in soils.

Factors influencing timber gluability with one-part polyurethanes – studied with nine Australian timber species

Holzforschung ◽  
2006 ◽  
Vol 60 (4) ◽  
pp. 423-428 ◽  
Author(s):  
Petri Widsten ◽  
Voytek S. Gutowski ◽  
Sheng Li ◽  
Tony Cerra ◽  
Sharon Molenaar ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sessile Drop ◽  
Lap Joints ◽  
Sessile Drop Method ◽  
Timber Species ◽  
Adhesion Properties ◽  
Factors Affecting ◽  
X Ray ◽  
Polyurethane Adhesives ◽  
Creep Loading

Abstract The bulk and surface properties of blocks of nine Australian wood species of commercial importance were investigated to elucidate the factors affecting timber gluability with structural one-component polyurethane adhesives. Cross-lap joints were prepared from freshly sanded blocks and the joints were subjected to creep loading in a condensing humidity environment. The median tensile strength (MTS) of the joints was found to improve with decreasing phenolic extractives content, lower timber density and decreasing lipophilic surface extractives content. The latter was assessed from O/C atomic ratios of the timber surfaces determined by X-ray photoelectron spectroscopy (XPS). The content of bulk lipophilic extractives and lignins and wettability of the surface as determined by the sessile drop method did not reveal significant correlations with the adhesion properties. The adhesion tests indicated significant gluability differences between the species investigated.

scholarly journals Novel amphiphilic polyvinylpyrrolidone functionalized silicone particles as carrier for low-cost lipase immobilization

2018 ◽  
Vol 5 (6) ◽  
pp. 172368 ◽  
Author(s):  
Shan Zhang ◽  
Qianchun Deng ◽  
Ya Li ◽  
Mingming Zheng ◽  
Chuyun Wan ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Rational Design ◽  
Low Cost ◽  
Immobilized Lipase ◽  
High Catalytic Activity ◽  
Lipase Immobilization ◽  
X Ray ◽  
Support Materials ◽  
Steady Rate ◽  
Loading Amount

The high catalytic activity, specificity and stability of immobilized lipase have been attracting great interest. How to reduce the cost of support materials has always been a hot topic in this field. Herein, for the development of low-cost immobilized lipase, we demonstrate an amphiphilic polyvinylpyrrolidone (PVP) grafted on silicone particle (SP) surface materials (SP-PVP) with a rational design based on interfacial activation and solution polymerization. Meanwhile, hydrophilic pristine SP and hydrophobic polystyrene-corded silicone particles (SP-Pst) were also prepared for lipase immobilization. SP-PVP was characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and thermogravimetry. Our results indicated that the lipase loading amount on the SP-PVP composites was about 215 mg of protein per gram. In the activity assay, the immobilized lipase SP-PVP@CRL exhibited higher catalysis activity and better thermostability and reusability than SP@CRL and SP-Pst@CRL. The immobilized lipase retained more than 54% of its initial activity after 10 times of re-use and approximately trended to a steady rate in the following cycles. By introducing the interesting amphiphilic polymer to this cheap and easily obtained SP surface, the relative performance of the immobilized lipase can be significantly improved, facilitating interactions between the low-cost support materials and lipase.

scholarly journals Adsorption of Pb(II) from Aqueous Solution by Mussel Shell-Based Adsorbent: Preparation, Characterization, and Adsorption Performance

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 741
Author(s):  
Quan Wang ◽  
Fangyuan Jiang ◽  
Xiao-Kun Ouyang ◽  
Li-Ye Yang ◽  
Yangguang Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Raw Material ◽  
Mussel Shell ◽  
Scanning Calorimetry ◽  
Factors Affecting ◽  
X Ray ◽  
Before And After ◽  
Freundlich Adsorption Isotherm ◽  
Mussel Shells ◽  
Shell Powder

As a natural biological adsorbent, shell powder is inexpensive, highly efficient, and does not leave any chemical residue; thus, it can be used to remove contaminants from water. In this study, we used mussel shells as a raw material to prepare an adsorbent. Scanning electron microscopy was used to observe the surface morphology of the mussel shell powder before and after calcination, and X-ray diffraction measurements, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller measurements were performed to analyze the structure and composition of calcined mussel shell powder. Characterization of the shell powder before and after calcination revealed a change from calcium carbonate to calcium oxide, as well as the formation of a surface porous structure. Using Pb(II) as a representative contaminant, various factors affecting the adsorption were explored, and the adsorption mechanism was analyzed. It was found that the adsorption is consistent with the Freundlich adsorption isotherm and the pseudo second-order model. The calcined mussel shell powder exhibits excellent adsorption for Pb(II), with an adsorption capacity reaching 102.04 mg/g.

scholarly journals Impact of Crystal Habit on the Dissolution Rate and In Vivo Pharmacokinetics of Sorafenib Tosylate

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3469
Author(s):  
Chi Uyen Phan ◽  
Jie Shen ◽  
Kaxi Yu ◽  
Jianming Mao ◽  
Guping Tang
Keyword(s):  
Dissolution Rate ◽  
Photoelectron Spectroscopy ◽  
Class Ii ◽  
Crystal Habit ◽  
Factors Affecting ◽  
X Ray ◽  
Bcs Class Ii ◽  
Rate Limiting Step ◽  
In Vivo Pharmacokinetics

The dissolution rate is the rate-limiting step for Biopharmaceutics Classification System (BCS) class II drugs to enhance their in vivo pharmacokinetic behaviors. There are some factors affecting the dissolution rate, such as polymorphism, particle size, and crystal habit. In this study, to improve the dissolution rate and enhance the in vivo pharmacokinetics of sorafenib tosylate (Sor-Tos), a BCS class II drug, two crystal habits of Sor-Tos were prepared. A plate-shaped crystal habit (ST-A) and a needle-shaped crystal habit (ST-B) were harvested by recrystallization from acetone (ACN) and n-butanol (BuOH), respectively. The surface chemistry of the two crystal habits was determined by powder X-ray diffraction (PXRD) data, molecular modeling, and face indexation analysis, and confirmed by X-ray photoelectron spectroscopy (XPS) data. The results showed that ST-B had a larger hydrophilic surface than ST-A, and subsequently a higher dissolution rate and a substantial enhancement of the in vivo pharmacokinetic performance of ST-B.

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