INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2016
·
IF 3.138
Hui Guo,Yi Tang,Yang Yu,Lu Xue,Jun-qing Qian
Enzyme immobilized on magnetic particles can be used as efficient recoverable biocatalysts under strong magnetic response. To enable re-use of enzyme, modified Fe 3 O 4 particles were used as carrier to immobilize α-amylase in this paper. Firstly, the surface of Fe 3 O 4 particles were coated with amino groups by direct using TEOS (tetraethoxysilane) followed by treatment with APTES (3-aminopropyltriethoxysilane) and then carboxylated by reacting it with succinic anhydride. In addition, the effect of the immobilization condition on enzyme activity recovery and immobilization efficiency were investigated. The results showed that the optimal immobilization occurred under following conditions: pH 5.5, 40 °C, enzyme concentration of 20 mg mL −1 , reaction time for 36 h. Using immobilized α-amylase as biocatalyst, the optimum pH and temperature for hydrolysis were observed to be 6.5 and 60 °C. The kinetics of hydrolysis reaction were studied using Michaelis–Menten equation. The affinity constant ( K m ) and maximum reaction rate ( v max ) of magnetic particles immobilization α-amylase (MPIA) was 0.543 mg mL −1 and 1.321 mg min −1 compared to those of 0.377 mg mL −1 and 6.859 mg min −1 of free enzyme. After immobilization, enzymatic activity, storage stability, thermo-stability, and reusability of MPIA were found superior to those of the free one. MPIA maintained 86% enzyme activity after 30 days and maintained 78% enzyme activity after recycling six times.
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高影响因子
ANALYTICAL SCIENCES
·
2017
·Vol. 33
·期 4
·481-486
·
IF 1.228
Juan WU,Yanbin JIANG,Lishi WANG,Qiang ZENG
In order to confirm the correlation between interfacial properties of modified surface plasmon resonance (SPR) chips and their SPR responses to immobilized anti-IgG, SPR chips were modified by mercaptoundecanoic acid, poly(ethylene glycol) diacrylate (PEG), PEG-based copolymer and cyclodextrin coupled PEG using self-assembled or radical polymerization methods. The resulting interfacial properties such as film thickness and hydrophilicity were characterized by AFM, elliptic polarization scanners and contact angle meter. Immobilization of human IgG on the modified chips was achieved by EDC/NHS activation through an amide bond. The association between fixed IgG and free anti-IgG was reflected by the variation of SPR responses and the binding ability was evaluated by Langmuir isotherms. As observed, the adsorption between IgG and anti-IgG was affected by the interfacial properties of different modifiers, such that a chip with a thinner and more hydrophilic layer may result in a higher SPR response, producing a larger adsorption equilibrium constant for protein interaction.
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高影响因子
MOLECULES
·
2017
·Vol. 22
·期 1
·179
·
IF 2.861
Chunfang Li,Shuhui Jiang,Xinying Zhao,Hao Liang
In this paper we report a facile method for preparing co-immobilized enzyme and magnetic nanoparticles (MNPs) using metal coordinated hydrogel nanofibers.Candida rugosalipase (CRL) was selected as guest protein. For good aqueous dispersity, low price and other unique properties, citric acid-modified magnetic iron oxide nanoparticles (CA-Fe3O4NPs) have been widely used for immobilizing enzymes. As a result, the relative activity of CA-Fe3O4@Zn/AMP nanofiber-immobilized CRL increased by 8-fold at pH 10.0 and nearly 1-fold in a 50 °C water bath after 30 min, compared to free CRL. Moreover, the immobilized CRL had excellent long-term storage stability (nearly 80% releative activity after storage for 13 days). This work indicated that metal-nucleotide nanofibers could efficiently co-immobilize enzymes and MNPs simultaneously, and improve the stability of biocatalysts.Keywords:metal;nucleotide;magnetic iron oxide nanoparticles;Candida rugoselipase (CRL);immobilized enzyme
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高影响因子
Journal of Engineered Fibers and Fabrics
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2016
·
IF 0.538
Quan Feng,Dingsheng Wu,Shan Huan,Man Li,Xin Li
In this paper, a novel nano-material was prepared, and then was applied for enzyme immobilization. Amidoxime ployarcylonitrile /montmorillonite (AOPAN/MMT) composite nanofibrous membranes were generated by electrospinning and amidoxime modification, then the nanofiber membranes were modified by glutaraldehyde; the modified AOPAN/MMT composite nanofibers were applied in laccase immobilization by adsorption and crosslinking method. Scanning electron microscopy was used to visualize the morphology of the nanofibers, and Fourier transform infrared spectroscopy was used to provide information on the surface chemistry of original and modified nanofibers. At the same time, the optimization of immobilization conditions and the relative properties of the immobilized laccase were also studied in this thesis. According to the experimental results the optimum conditions of laccase immobilization were obtained: glutaraldehyde concentration, crosslinking time, enzyme immobilization time were determined as 5%, 10 h and 12 h, respectively. The immobilized laccase showed a better stability resistance to temperature and pH change. Comparison of storage stabilities showed that the immobilized laccase retained more than 62.6% of its initial activity when stored at 4°C for 20 days. However, the free laccase lost most of its activity under the same conditions. The immobilized laccase retained 64.5% of its initial activity after 10 repeated batches of reaction.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2016
·
IF 2.567
Bing Xue,Lei Hui,Huaqin Yang,Yulai Zhao,Linxi Hou,Wei Li
A macroporous SiO2 (Macro-SiO2), which has uniformed macropores, an open-framework structure, and thin walls, was synthesized to support Ziegler–Natta catalysts. The immobilization behaviors of the Ziegler–Natta catalysts inside the Macro-SiO2 were investigated. Notable agglomerations of δ-MgCl2/titanium complex were observed because of the unconstrained environment of the Macro-SiO2. A highly superficial Ti content and a heterogeneously chemical structure of Ti active sites were thus achieved inside the Macro-SiO2. The ethylene polymerization results revealed that the Macro-SiO2/MgCl2/TiCl4 exhibited much higher catalytic activity (i.e., 12.1 × 106 g PE·(mol Ti·h)−1 or 17.8 × kg PE·(g cat·h)−1) than that of the traditional 955-SiO2 supported catalyst (i.e., 2.0 × 106 g PE·(mol Ti·h)−1 or 2.7 × kg PE·(g cat·h)−1). Finally, the fragmentation behavior of Macro-SiO2/MgCl2/TiCl4 was investigated during the polymerization. This unconstrained environment of Macro-SiO2 afforded fewer resistances to the diffusion of reactants and also the polymer growth.
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JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2015
·Vol. 162
·期 12
·B291
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IF 3.266
Feng Gao,Xili Cai,Hidekazu Tanaka,Qionghua Zhu,Fei Gao,Qingxiang Wang
An ultrasensitive DNA biosensor was constructed in this work by using graphene oxide nanosheets (GONs) as the multi-site platform for probe DNA immobilization. First, L-cysteine (L-cys) was self-assembled on a gold electrode surface based on the Au-S chemistry. Then the GONs and amino modified probe DNA was covalently grafted to L-cys/AuE surface in turn, with the aid of 1-(3-Dimethylanminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-Hydroxy succinimide (NHS). The layer upon layer assembly process was characterized with atomic force microscopy and electrochemical methods. Due to the nano-size effect and multiple site characteristic of GONs, the immobilization density of the probe DNA was determined to be as high as 5.72 × 10−10 mol cm−2 using methylene blue as the redox probe. The hybridization experiments showed that the biosensor can quantitatively detect target DNA in a wide range from 1.0 × 10−15 M to 1.0 × 10−9 M with a detection limit of 5.0 × 10−16 M. The selectivity experiments showed that the sensing system could accurately discriminate the complementary sequence from the base mismatched and non-complementary sequences.
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BIOSENSORS & BIOELECTRONICS
·
2014
·
IF 6.451
Xiang Zhu,Xiangheng Niu,Hongli Zhao,Jie Tang,Minbo Lan
Monitoring of reactive oxygen species like superoxide anion (O 2 ∙− ) turns to be of increasing significance considering their potential damages to organism. In the present work, we fabricated a novel O 2 ∙− electrochemical sensor through immobilizing superoxide dismutase (SOD) onto a Pt–Pd/MWCNTs hybrid modified electrode surface . The Pt–Pd/MWCNTs hybrid was synthesized via a facile one-step alcohol-reduction process, and well characterized by transmission electron microscopy , X-ray photoelectron spectroscopy and X-ray diffraction. The immobilization of SOD was accomplished using a simple drop-casting method, and the performance of the assembled enzyme-based sensor for O 2 ∙− detection was systematically investigated by several electrochemcial techniques. Thanks to the specific biocatalysis of SOD towards O 2 ∙− and the Pt–Pd/MWCNTs – promoted fast electron transfer at the fabricated interface, the developed biosensor exhibits a fast, selective and linear amperometric response upon O 2 ∙− in the concentration scope of 40–1550 μM ( R 2 =0.9941), with a sensitivity of 0.601 mA cm −2 mM −1 and a detection limit of 0.71 μM ( S / N =3). In addition, the favorable biocompatibility of this electrode interface endows the prepared biosensor with excellent long-term stability (a sensitivity loss of only 3% over a period of 30 days). It is promising that the proposed sensor will be utilized as an effective tool to quantitatively monitor the dynamic changes of O 2 ∙− in biological systems.
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高影响因子
RSC Advances
·
2015
·Vol. 5
·期 126
·103943-103955
·
IF 3.84
Yongbo Shao,Tao Jing,Jingzhi Tian,Yongjie Zheng
Nano- and hybrid materials have recently emerged as a new approach for improving enzyme activity and stability, and are suitable for commercial applications. In this paper, graphene oxide-based magnetic hybrids were prepared successfully. A chloropropyl-functionalized graphene oxide decorated with Fe3O4 nanoparticles was made, denoted as CPS/GO-Fe3O4@MCM-41. This was characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, thermogravimetry and N2 adsorption/desorption. Then, porcine pancreas lipase (PPL) was immobilized onto the graphene oxide-based magnetic nanoparticles via covalent bonding. The results show that the novel supporting material CPS/GO-Fe3O4@MCM-41 was the best for PPL immobilization compared to two other nanomaterials (GO-Fe3O4@MCM-41 and GO-Fe3O4). The supporting material CPS/GO-Fe3O4@MCM-41 exhibited enhanced immobilization efficiency (up to 98%), maximum relative activity (up to 97.9%), high stability and reusability (85% after 56 d and 87% after 10 cycles respectively, both at 30 °C). Additionally, it offered some other advantages, such as easy recycling and reuse, complying with the requirements of green chemistry. Therefore, it is proposed that CPS/GO-Fe3O4@MCM-41 provides a new approach for commercial applications.
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高影响因子
Science China-Chemistry
·
2015
·Vol. 58
·期 6
·1056-1064
·
IF 1.695
Zheng Jiangnan,Lin Zian,Zhang Lan,Yang Huanghao
In this work, we demonstrate for the first time, a method to synthesize phenylboronic acid-Fe 3 O 4 @polydopamine (Fe 3 O 4 @PDA-PBA) magnetic microspheres via the combination of mussel-inspired polydopamine coating and click chemistry. Uniform-size and core-shell structured Fe 3 O 4 @PDA-PBA magnetic microspheres with a core diameter of ∼240 nm and a shell thickness of ∼13 nm were obtained as identified by the characterization of the morphology, structure and composition of the synthesized microspheres. We evaluated the selectivity and binding capacity of the Fe 3 O 4 @PDA-PBA magnetic microspheres by using standard glycoproteins (ovalbumin, immunoglobulin G and catalase) and nonglycoproteins (human serum albumin, bovine hemoglobin, myoglobin, lysozyme, and ribonuclease A) as model proteins. Adsorption experiments, SDS-PAGE and mass spectrometry analysis demonstrated that the Fe 3 O 4 @PDA-PBA magnetic microspheres had much high binding capacity and selectivity for glycoproteins/glycopeptides compared to nonglycoproteins/nonglycopeptides. In addition, the practicability of the Fe 3 O 4 @PDA-PBA magnetic microspheres was further assessed by selective capture of glycoproteins from healthy human serum. The good results demonstrated its potential in glycoproteome analysis.
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高影响因子
ENVIRONMENTAL POLLUTION
·
2024
·
IF 7.6
Ying Zhao,Xinyi Zhang,Haotian Xue,Bin Gong,Qingxu Li,Wenshan Guo,Xiaoguang Meng
Antimony (Sb) contamination in certain areas caused by activities such as antimony mining and smelting poses significant risks to human health and ecosystems. In this study, a stable composite material consisting of natural zeolite-supported nanoscale zero-valent iron (Z-ZVI) was successfully prepared. The immobilization effect of Z-ZVI on Sb in contaminated soil was investigated. Experimental results showed that Z-ZVI exhibited superior performance compared to pure nano zero-valent iron (nZVI) in terms of stability, with a lower zeta potential (−25.16 mV) at a pH of 7 and a higher specific surface area (54.54 m 2 /g). It can be easily applied and dispersed in contaminated soils. Additionally, Z-ZVI demonstrated a more abundant porous structure. After 60 days of treatment with 3% Z-ZVI, the leaching concentration of Sb in the contaminated soil decreased from 1.32 mg/L to 0.31 mg/L (a reduction of 76%), and the concentration of available Sb species decreased from 19.84 mg/kg to 0.71 mg/kg, achieving a fixation efficiency of up to 90%. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis confirmed the effective immobilization of Sb in the soil through reduction of antimonate to antimonite , precipitation, and adsorption processes facilitated by Z-ZVI. Moreover, the addition of Z-ZVI effectively reduced the bioavailability of Sb in the contaminated soil, thereby mitigating its toxicity to earthworms. In conclusion, Z-ZVI can be utilized as a promising material for the safe remediation and antimony and other heavy metal-contaminated soils.
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高影响因子
PLoS One
·
2024
·Vol. 19
·期 1
·e0297149
·
IF 2.9
Zhixiang Lv,Zhou Wang,Shaobo Wu,Xiang Yu
With the emergence of penicillin resistance, the development of novel antibiotics has become an urgent necessity. Semi-synthetic penicillin has emerged as a promising alternative to traditional penicillin. The demand for the crucial intermediate, 6-aminopicillanic acid (6-APA), is on the rise. Enzyme catalysis is the primary method employed for its production. However, due to certain limitations, the strategy of enzyme immobilization has also gained prominence. The magnetic Ni 0.4 Cu 0.5 Zn 0.1 Fe 2 O 4 nanoparticles were successfully prepared by a rapid-combustion method. Sodium silicate was used to modify the surface of the Ni 0.4 Cu 0.5 Zn 0.1 Fe 2 O 4 nanoparticles to obtain silica-coated nanoparticles (Ni 0.4 Cu 0.5 Zn 0.1 Fe 2 O 4 -SiO 2 ). Subsequently, in order to better crosslink PGA, the nanoparticles were modified again with glutaraldehyde to obtain glutaraldehyde crosslinked Ni 0.4 Cu 0.5 Zn 0.1 Fe 2 O 4 -SiO 2 -GA nanoparticles which could immobilize the PGA. The structure of the PGA protein was analyzed by the PyMol program and the immobilization strategy was determined. The conditions of PGA immobilization were investigated, including immobilization time and PGA concentration. Finally, the enzymological properties of the immobilized and free PGA were compared. The optimum catalytic pH of immobilized and free PGA was 8.0, and the optimum catalytic temperature of immobilized PGA was 50°C, 5°C higher than that of free PGA. Immobilized PGA in a certain pH and temperature range showed better catalytic stability. V max and K m of immobilized PGA were 0.3727 μmol·min -1 and 0.0436 mol·L -1 , and the corresponding free PGA were 0.7325 μmol·min -1 and 0.0227 mol·L -1 . After five cycles, the immobilized enzyme activity was still higher than 25%.
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Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Saeed Rehman,Jiayan Wu,Muddasir Hanif,Tianming Wang,Minye Huang,Tang Hongmei,Shang Zhongbo,Pingxiao Wu,Fazal Raziq
This research is focused on studying the effects of different dissolved organic matter (DOM) and electrolyte concentration on the Cd(II) adsorption on halloysite (HNT) surfaces. The DOM significantly decreased the Cd(II) adsorption by more than 25 %. Soil derived dissolved organic matter (SDT) showed the greatest negative impact, followed by humic acid (HA) and Fulvic acid (FA). The effects of background electrolytes NaCl and NH 4 Cl showed that both salts can undergo complexation with metals. Furthermore, the DOM (SDT/FA/HA) can cover the major HNT surface and the Cd(II) adsorption may occur due to outer-sphere complexation and ion exchange. Additionally, the influence of 100 mML −1 of NaCl on the aggregation tendencies of HNT has demonstrated that the presence of DOM amplifies the aggregation behavior of these nanotubes . The interaction energy barrier between HNT particles is dependent on physicochemical characteristics of DOM that inhibits Cd(II) sorption . These findings suggested that the HNT reduction, electrostatic repulsion and site-competition are the prominent mechanisms to decrease the Cd(II) immobilization on the HNT. The extent of Cd(II) adsorption/desorption on HNT surface followed the order of FA > HA > SDT/ HA > SDT > FA.
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