ENZYME AND MICROBIAL TECHNOLOGY
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2018
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IF 2.932
Juan Han,Yunfeng Cai,Yun Wang,Lei Gu,Chunmei Li,Yanli Mao,Wenli Zhang,Liang Ni
In this work, a novel Ni 2+ &AABOB bifunctional core–shell magnetic composite nanoparticles (MNPs), Fe 3 O 4 @p(AABOB-co-AIM-Ni 2+ ), were synthesized for the immobilization of horseradish peroxidase (HRP). Two kinds of interaction are simultaneously incorporated to improve the stability and reusability of immobilized HRP: one is the coordination between Ni 2+ and amide group in HRP, and the other is the interaction of the wulff-type boronic acid group with cis-diol-containing HRP which belongs to a type of glycoproteins. Accordingly, the proposed approach achieved high enrichment capacity (174.75 mg/g, protein/beads), and the activity of immobilized HRP still achieved 80% after reuse for 5 cycles. The degradation efficiency of phenol in the presence of immobilized HRP reached 93% within 10 min, which was significantly higher than that of free HRP only about 50% within 20 min. In addition, the immobilized HRP can be easily separated from the reaction solution by an external magnetic field.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2024
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IF 7.7
Xuewu Liu,Xingfei Li,Zhengjun Xie,Xing Zhou,Long Chen,Chao Qiu,Cheng Lu,Zhengyu Jin,Jie Long
Agarose from biomass can be used to synthesize the rare sugar 3,6-anhydro- L -galactose ( L -AHG), and the new synthesis route and functional properties of L -AHG have always been the focus of research. Here we developed a novel method to co-immobilize Aga50D and Bp GH117 onto streptavidin-coated magnetic nanoparticles and achieved the conversion of agarose to bioactive L -AHG in one pot. Results showed that enzymes were successfully immobilized on the carrier. The activity of co-immobilized enzymes was 2.5-fold higher than that of single immobilized enzymes. Compared with free enzymes, co-immobilized enzymes exhibited enhanced thermal stability. The co-immobilized enzymes retained 79.45 % relative activity at 40 °C for 3 h, while the free enzymes only possessed 21.40 % residual activity. After eight cycles, the co-immobilized enzymes still retained 73.47 % of the initial activity. After silica gel chromatography, the purity of L -AHG obtained by co-immobilized enzymes hydrolysis reached 83.02 %. Furthermore, bioactivity experiments demonstrated that L -AHG displayed better antioxidant and antibacterial effects than neoagarobiose. L -AHG had broad-spectrum antibacterial activity, while neoagarobiose and D -galactose did not show an obvious antibacterial effect. This study provides a feasible method for the production of L -AHG by a co-immobilized multi-enzyme system and confirms that L -AHG plays a key role in the bioactivity of neoagarobiose.
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ENZYME AND MICROBIAL TECHNOLOGY
·
2025
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IF 3.7
Yue Zhang,Chi Lei,Liangzhi Li,Bin Zou,Tao Xu,Lishi Yan
In this study, chemical modification coupled with immobilization of cellulase was developed for simultaneous pretreatment and saccharification (SPS) of lignocellulosic biomass in ternary deep eutectic solvent (DES). Cellulase was firstly modified with acid anhydrides to form citraconic anhydride modified cellulase (CA-Ce) and phthalic anhydride modified cellulase (PA-Ce), respectively. Then the modified cellulases were immobilized on amino-functionalized mesoporous silica nanoparticles (MSN-NH 2 ) to fabricate CA-Ce@MSN-NH 2 and PA-Ce@MSN-NH 2 . A series of physiochemical characterizations were employed to characterize modified cellulases or immobilization carriers. Thermodynamic analysis and deactivation kinetics in ternary DES (NMMO/Bet/OA) revealed that CA-Ce@MSN-NH 2 had desired thermal stability and solvent tolerance, which maintained 80.5 % initial activity at 70 °C and 77.8 % initial activity in 50 % NMMO/Bet/OA. The SPS of bagasse in NMMO/Bet/OA via CA-Ce@MSN-NH 2 resulted in 84.1 % total reducing sugar (TRS) yield at optimal condition.
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ACS Applied Materials & Interfaces
·
2015
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IF 6.723
Mengzhen Dai,Lingen Sun,Long Chao,Yueming Tan,Yingchun Fu,Chao Chen,Qingji Xie
Electrochemical/chemical oxidative synthesis and biosensing/biofuel cell applications of poly(L-DOPA) (PD) are studied versus polydopamine (PDA) as a recent hotspot biomaterial. The enzyme electrode developed by coelectrodeposition of PD and glucose oxidase (GOx), uricase, or tyrosinase shows biosensing performance superior to that of the corresponding PDA-based enzyme electrode. The chemical oxidative polymerization of L-DOPA (PDC) by NaAuCl4 in GOx-containing neutral aqueous solution is used to immobilize GOx and gold nanoparticles (AuNPs). The thus-prepared chitosan (CS)/GOx-PDC-AuNPs/Auplate/Au electrode working in the first-generation biosensing mode responds linearly to glucose concentration with a sensitivity of 152 μA mM–1 cm–2, which is larger than those of the CS/GOx-PDAC-AuNPs/Auplate/Au electrode, the CS/GOx-poly(3-anilineboronic acid) (PABA)-AuNPs/Auplate/Au electrode, and the most reported GOx-based enzyme electrodes. This PDC-based enzyme electrode also works well in the second-generation biosensing mode and as an excellent bioanode in biofuel cell construction, probably because PD as an amino acid polymer has the higher biocompatibility and the more favorable affinity to the enzyme than PDA. The PD material of great convenience in synthesis, outstanding biocompatibility for preparing high-performance bionanocomposites, and strong capability of multifunctional coatings on many surfaces may find wide applications in diversified fields including biotechnology and surface-coating.
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Small
·
2015
·Vol. 11
·期 47
·6338-6346
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IF 8.368
Jing Tan,Chuanyu Sun,Ke Xu,Changchun Wang,Jia Guo
5-Aminolevulinic acid (ALA) is a widely used photodynamic therapy (PDT) prodrug in the clinic. It can be metalized to the photosensitizer PpIX, which produces toxic singlet oxygen to kill cancer cells upon visible light irradiation. Herein, a core/shell-structured vehicle is designed to comprise magnetite colloidal supraparticles (MCSPs) as cores and ALA-Zn II coordination polymers as shells (Fe 3 O 4 @ALA-Zn II ) for target pro-photosensitizer delivery. The coordination polymers with 2D layered structures are locally deposited on the MCSPs by the complexation of the ALA and Zn II ions, and are readily controlled by varying the feed precursors and reaction temperatures. The maximum conjugated ALA amount is up to 17%. The Fe 3 O 4 @ALA-Zn II microspheres exhibit pH-sensitive release of ALA in acidic environment and rapid magnetic responsiveness. Cytotoxicity results demonstrate that Fe 3 O 4 @ALA-Zn II shows a significant inhibitory effect to T24 cells and is nontoxic to 293T normal cells as exposed to the 630 nm visible light for a very short time, which may due to the selective accumulation of ALA-induced PpIX in T24 cancer cells. Compared to the ALA used alone, the coordination polymer form is more efficient because of the bioactivity of incorporated Zn ions despite underlying the same apoptosis mechanism as ALA agent.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2016
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IF 2.567
Binglin Li,Jiao Wang,Xiaoli Zhang,Binxia Zhao
Phospholipase D (PLD) was immobilized in a simple and effective way by adsorption and precipitation of the enzyme, followed by chemical cross-linking to form an “enzyme net” covering the surface of nonporous silicon dioxide nanoparticles. For catalyzing transphosphatidylation to produce phosphatidylethanolamine (PE), at pH 6.0 and 35 °C (the optimum operational conditions), the specific activity of immobilized PLD reached 15872 U/gprotein, which was approximately 1.15 times higher than the maximum value of specific activity of free PLD (13813 U/gprotein). A kinetic study demonstrates immobilized PLD had increases in catalytic activity and enzyme–substrate affinity. In addition, the thermostability and pH tolerance were significantly enhanced compared with free PLD. The half-life of immobilized PLD was significantly increased from 30 to 70 days at 4 °C (approximately 2.3 times). This novel method has been proven to be suitable for the production of robust biocatalysts.
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SEPARATION SCIENCE AND TECHNOLOGY
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2016
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IF 1.083
Xu Liu,Meng Wang,Yu-xiang Jia
The existence of numerous non-conductive regions retards the further functionalization of heterogeneous membrane surface. In this report, a modification scheme for covalent immobilization of polyethyleneimine (PEI) multilayer on heterogeneous cation exchange membrane (CEM) was developed by means of diazonium-induced carboxyl group grafting. Of particular note are the influences of some important modification conditions, including the molecular weight of PEI and its deposition times, which were explored and understood. Series of electrodialysis experiments confirmed the achievement of the monovalent cation permselectivity. Furthermore, the results also indicated that the PEI coating can also effectively improve surface homogeneity and then alleviate concentration polarization behaviour during the electrodialysis process.
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ANALYTICA CHIMICA ACTA
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2016
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IF 4.712
Sheying Dong,Dandan Zhang,Gaochao Suo,Wenbo Wei,Tinglin Huang
A novel multi-function Metal-Organic Framework composite Ag@Zn-TSA (zinc thiosalicylate, Zn(C 7 H 4 O 2 S), Zn-TSA) was synthesized as highly efficient immobilization matrixes of myoglobin (Mb)/glucose oxidase (GOx) for electrochemical biosensing. The electrochemical biosensors based on Ag@Zn-TSA composite and ionic liquid (IL) modified carbon paste electrode (CPE) were fabricated successfully. Furthermore, the properties of the sensors were discussed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometric current-time curve, respectively. The results showed the proposed biosensors had wide linear response to hydrogen peroxide (H 2 O 2 ) in the range of 0.3–20,000 μM, to nitrite (NO 2 − ) for 1.3 μM–1660 μM and 2262 μM–1,33,000 μM, to glucose for 2.0–1022 μM, with a low detection limit of 0.08 μM for H 2 O 2 , 0.5 μM for NO 2 − , 0.8 μM for glucose. The values of the apparent heterogeneous electron transfer rate constant ( k s ) for Mb and GOx were estimated as 2.05 s −1 and 2.45 s −1 , respectively. Thus, Ag@Zn-TSA was a kind of ideal material as highly efficient immobilization matrixes for sensitive electrochemical biosensing. In addition, this work indicated that MOF nanocomposite had a great potential for constructing wide range of sensing interface.
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BIOSENSORS & BIOELECTRONICS
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2015
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IF 6.409
Yizhen Yang,Feng Gao,Xili Cai,Xiaoning Yuan,Suyu He,Fei Gao,Hongxu Guo,Qingxiang Wang
A versatile nanocomposite containing β-cyclodextrin and graphene (CD–GR) was prepared through a simple chemical reduction method. The characterization experiments show that the nanocomposite remains the flake-like morphology of GR, but its solubility and stability in aqueous solution are greatly improved. Then the nanocomposite was modified at glassy carbon electrode (GCE) surface, and was used as a functional matrix for the covalent immobilization of probe DNA using 2,4,6-trichloro-1,3,5-triazine (TCT) as the crosslinker . Due to the synergetic effect of large surface area of GR and rich hydroxyl of CD, the probe density for the developed biosensor was determined to as high as 3.82×10 13 molecules cm − 2 . Meanwhile, the biosensor shows high hybridization efficiency and hybridization kinetic. When the biosensor was applied for the impedance-based hybridization test, a wide linear range from 1.0×10 −16 to 1.0×10 −12 M and an ultralow detection limit of 3.4×10 −17 M were achieved. The biosensor also displays excellent stability, selectivity , and reproducibility.
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BIOCONJUGATE CHEMISTRY
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2014
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IF 4.821
Zhenyuan Qu,Kaimin Chen,Hongchen Gu,Hong Xu
Polymeric brushes have emerged as a novel 3D material platform that provides great amounts of binding sites for biomolecules. This paper investigates the covalent immobilization mechanism of protein by spherical poly(acrylic acid) brushes (SPAABs) in the widely adopted N-hydroxysuccinimide/N-(3-dimethyl-aminopropyl)-N′-ethylcarbodiimide hydrochloride (NHS/EDC) process. It was discovered that electrostatic interaction plays a crucial role in the covalent immobilization of protein. Due to the existence of 3D architecture and “Donnan effect”, SPAABs exhibit quite different immobilization kinetics in comparison with conventional 2D materials. Under conditions favorable to electrostatic interaction, the effect of “electrostatic interaction induced covalent binding” was observed as a result of competitive immobilization by physical adsorption and chemical binding. On the basis of the mechanism study, a new “chemical conjugation after electrostatic entrapment” (CCEE) method was developed which set the chemical and physical immobilization process apart. A more effective and well-defined covalent immobilization was achieved. And the binding capacity can be tuned in a wide range (0–4.2 mg protein/mg SPAABs) with a high level of control.
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CORROSION SCIENCE
·
2013
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IF 3.615
Yingqi Chen,Guojiang Wan,Juan Wang,Sheng Zhao,Yuancong Zhao,Nan Huang
Magnesium-based materials are promising in biodegradable implants, but the proper corrosion control is a challenge. Phytic acid has potential as a coating on Mg to control the degradation rate. An alkaline pre-treatment process is implemented to form the hydroxyl group on the Mg surface and covalently immobilize phytic acid. The surface-immobilized phytic acid molecules chelate with Mg to form a dense and homogenous protective coating. The coated Mg exhibits a smaller corrosion current density and degradation rate as compared to bare Mg in the phosphate buffered saline.
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JOURNAL OF MEMBRANE SCIENCE
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2013
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IF 4.093
Meng Wang,Yu-xiang Jia,Ting-ting Yao,Kai-kai Wang
In this work, the monovalent selectivity was successfully endowed to conventional cation exchange membrane by photo-induced covalent immobilization and self-crosslinking of chitosan. The chemical and morphological changes of the membrane surface after modification were examined by Fourier transform infrared spectroscopy , X-ray photoelectron spectroscopy and atomic force microscopy . Then, some electrodialysis experiments for Na + /Mg 2+ system and H + /Zn 2+ system which were used to simulate the seawater concentration and the hydrometallurgy applications, respectively, were performed to evaluate the monovalent selectivity of the modified membranes. Subsequently, diffusion experiments of NaCl and current–voltage curve measurement experiments were also conducted to comprehensively estimate membrane properties, such as diffusion coefficient of NaCl, membrane electrical resistance and limiting current density. Moreover, the influences of some further treatments for increasing charging intensity and compactness of the immobilized chitosan layer, including quarternization or/ and crosslinking, on membrane properties, were also investigated and analyzed. These contributed to recognize the dominant factors in selective separation and pave the road for tailoring the modified membranes for some specified applications. Anyway, the experimental results have clearly showed that the modified method put forward in this study was promising due to its facility, low cost and efficiency.
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