Biomolecules
·
2021
·Vol. 11
·期 10
·1399
·
IF 4.879
Kongliang Xu,Bin Wang,Chenlu Si,Chaoping Lin,Renchao Zheng,Yuguo Zheng
As a type of important and versatile biocatalyst, amidase immobilization on solid materials has received broad attention with its relatively easy procedure and available reusability. However, current porous supports have suffered from limited loadings, and it is highly desired to develop a new type of material with abundant space so as to ensure a high loading of amidase. Here, graphene oxide was adopted as the support for amidase immobilization, which showed the highest loading capacity for amidase (~3000 mg/g) to date. To the best of our knowledge, it is the first case of amidase immobilized on graphene oxide. Through surface modulation via reducing the contents of oxygen-containing functional groups, activity recovery of immobilized amidase increased from 67.8% to 85.3%. Moreover, surface-modulated graphene oxide can efficiently uptake amidase under a wide range of pH, and the maximum loading can reach ~3500 mg/g. The resultant biocomposites exhibit efficient biocatalytic performance for asymmetric synthesis of a chiral amino acid (i.e., L-4-fluorophenylglycine, an intermediate of aprepitant).Keywords:amidase;enzyme immobilization;graphene oxide;high loading;biocatalysis;surface modulation
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FOOD AND AGRICULTURAL IMMUNOLOGY
·
2020
·
IF 0
Lei Ma,Xi Qiu,Yaqi Li,Sheng Tang,Wei Shen,Changrui Xing,Dezhao Kong,Jianguo Sheng
Ochratoxin A (OTA) is a highly toxic potential contaminant of most agricultural products, and OTA is difficult to remove in general food production processes. In this study, we immobilized polyvinyl pyrrolidone-coated carboxypeptidase A (CPA) into zeolitic imidazolate framework material to improve the ability for OTA degradation. In this method, carboxypeptidase A was dispersed well in the material and maintained its stability and ability to degrade OTA, under complex matrix conditions with better repeated use performance than free carboxypeptidase A. The substrate conversion rate of CPA increased 3 times after immobilization. After repeated use of 10 cycles, the composite enzyme still retained 71.37% of its initial activity. The degradation rate of OTA was 30.69% higher than that of free CPA. This method may play an important role in the degradation of mycotoxins.
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Biomed Research International
·
2019
·
IF 2.197
Shihui Liu,Youdong Hu,Rongrong Tao,Qingwei Huo,Lin Wang,Chunzhi Tang,Changjiang Pan,Tao Gong,Nenggui Xu,Tao Liu
Vascular stent interventional therapy is the main method for clinical treatment of coronary artery diseases. However, due to the insufficient biocompatibility of cardiovascular materials, the implantation of stents often leads to serious adverse cardiac events. Surface biofunctional modification to improve the biocompatibility of vascular stents has been the focus of current research. In this study, based on the structure and function of extracellular matrix on vascular injury healing, a novel fibronectin-loaded poly-l-lysine/heparin nanoparticles was constructed for stent surface modification. In vitro blood compatibility evaluation results showed that the nanoparticles-modified surface could effectively reduce platelet adhesion and activation. In vitro cellular compatibility evaluation results indicated that the nanocoating may provide adequate efficacy in promoting the adhesion and proliferation of endothelial cells and thereby accelerate endothelialization. This study provides a new approach for the surface biological function modification of vascular stents.
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CARBOHYDRATE POLYMERS
·
2019
·
IF 6.044
Hu Tu,Guomin Wu,Yang Yi,Mengtian Huang,Rong Liu,Xiaowen Shi,Hongbing Deng
Novel antimicrobials with well biocompatibility are urgently needed for human public health protecting. Here, the silk fibroin (SF) nanofibrous mats coated with carboxymethyl chitosan (CMC), both extracted from natural polymers, were fabricated by combining electrospinning and electrostatic layer-by-layer (LBL) self-assembly techniques. The amphoteric CMC could be easily adsorbed on the surface of SF nanofibers due to the electrostatic interaction, which were a highly efficient and “green” route for the surface modification of SF mats. The mats after LBL procedure exhibited better hydrophilicity and stronger mechanical properties. The experimental results demonstrated that the LBL modified mats not only kept well biocompatibility but also obtained extremely enhanced antibacterial activity. More importantly, the mats displayed better bacterial inhibition with the increased CMC layers. LBL 10 and LBL 10.5 owned the antibacterial activity of more than 67% at the bacterial concentrations of 10 6 cfu ml −1 after 24 h cultivation, which implied that these novel natural polymer-based materials could be utilized as wound dressings for clinical skin and tissue regeneration, especially for infected wounds.
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Materials
·
2019
·Vol. 12
·期 7
·1163
·
IF 2.972
Jiali Xue,Kuibao Zhang,Zongsheng He,Wenwen Zhao,Weiwei Li,Dayan Xie,Baozhu Luo,Kai Xu,Haibin Zhang
A rapid and effective method is necessary in the disposal of severely radioactive contaminated soil waste. Simulated Ce-bearing radioactive soil waste was immobilized by self-propagating high-temperature synthesis (SHS) within 5 min in this study. The main work includes the rapid synthesis of soil waste forms, the analysis of phase composition, microstructure and chemical durability. These results show that the simulated nuclide Ce was successfully immobilized into the pyrochlore-rich waste matrice, whose main phases are SiO2, pyrochlore (Gd2Ti2O7) and Cu. The normalized leaching rates of Si and Na on the 42nd day are 1.86 × 10−3and 1.63 × 10−2g·m−2·d−1, respectively. And the normalized leaching rate of Ce also remains at low level (10−5–10−6g·m−2·d−1) within 42 days.Keywords:Radioactive soil waste;Gd2Ti2O7pyrochlore;SHS;CeO2;Immobilization
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SENSORS
·
2019
·Vol. 19
·期 3
·640
·
IF 3.031
Meng Li,Jing Wu,Haiping Su,Yan Tu,Yazhuo Shang,Yifan He,Honglai Liu
In this work, three different aqueous solutions containing imidazole-based ILs with different alkyl chain lengths ([Cnmim]Br,n= 2, 6, 12) were adopted as the medium for the synthesis of ionic liquid-polypyrrole (IL-PPy) composites. Herein, the ILs undertook the roles of the pyrrole solvent, the media for emulsion polymerization of PPy and PPy dopants, respectively. The electrochemical performances of the three IL-PPy composites on a glassy carbon electrode (GCE) were investigated by electrochemical experiments, which indicated that [C12mim]Br-PPy (C12-PPy) composites displayed better electrochemical performance due to their larger surface area and firmer immobilization on the GCE. Further, C12-PPy/GCE were decorated with Au microparticles by electrodeposition that can not only increase the conductivity, but also immobilize sufficient biomolecules on the electrode. Then, the obtained C12-PPy-Au/GCE with outstanding electrochemical performance was employed as a horseradish peroxidase (HRP) immobilization platform to fabricate a novel C12-PPy-Au-HRP/GCE biosensor for H2O2detection. The results showed that the prepared C12-PPy-Au-HRP/GCE biosensor exhibited high sensitivity, fast response, and a wide detection range as well as low detection limit towards H2O2. This work not only provides an outstanding biomolecule immobilization matrix for the fabrication of highly sensitive biosensors, but also advances the understanding of the roles of ILs in improving the electrochemical performance of biosensors.Keywords:ionic liquids (ILs);polypyrrole (PPy);gold particles;horseradish peroxidase (HRP);enzyme immobilization;hydrogen peroxide sensor
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BIOSENSORS & BIOELECTRONICS
·
2019
·
IF 9.518
Fang Li,Tianli Liu,Hong Wang,Yuming Dong,Guang-Li Wang
We propose herein an immobilization-free, split-mode cathodic photoelectrochemical (PEC) strategy coupled with a cascaded amplification for versatile biosensing. Taking DNA and microRNA (miRNA) as the model targets, the hybridization between the targets and the hairpin probe triggers the digestion of the probe DNA by T7 exonuclease (T7 Exo), thus to generate G-quadruplex (G4) forming sequences, and then the released targets (DNA or miRNA) initiate the subsequent cycling processes and generate a large amount of G4 forming sequences. Subsequently, the formed G4 sequences associate with hemin to form the G4/hemin DNAzyme, which catalytically produces 1,4-bezoquinone (BQ) for conjugating onto the surface of the chitosan (CS) deposited BiOI/ITO photocathode via the quinone-chitosan conjugation chemistry (QCCC). Under photo excitation, the covalently attached quinones can act as electron acceptors of bismuth oxyiodine (BiOI), promoting the photocurrent generation and thus allowing the elegant and “signal-on” mode for probing targets of interest. Highly sensitive and selective PEC bioassays are readily realized, with the detection limits down to 2.2 fM (for DNA) and 0.2 fM (for miRNA). Since no labeling and no electrode modification processes are needed, this split-mode PEC biosensing strategy is amenable to convenient, time/labor saving, and high-throughput detections. More significantly, it provides a novel concept to design immobilization-free and label-free cathodic PEC biosensing systems, and showcases promise in general and versatile bioanalysis research.
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FOOD CHEMISTRY
·
2019
·
IF 5.399
Zhen Qin,Si Lin,Yongjun Qiu,Qiming Chen,Yin Zhang,Jiachun Zhou,Liming Zhao
Immobilization of enzymes is an essential strategy with outstanding prospects in biocatalytic processes. Nontoxic, inexpensive immobilized enzyme approach is especially important for food enzymes. We here demonstrate that a carbohydrate-binding module family 56 domain (CBM56-Tag) mediates the immobilization of fusion enzymes with the curdlan (β-1,3-glucan) particle support, thereby enabling the one-step immobilization-purification of target enzymes. CBM56-Tag exhibits an immunoglobulin-like β-sandwich fold, which can be adsorbed by curdlan via hydrogen bond-mediated binding. The maximum adsorption capacity of a fusion chitosanase (CBM56-GsCsn46A) on curdlan is 50.72 mg/g. The immobilized enzyme could be directly used in the packed-bed reactor. This immobilization strategy utilizes a natural polysaccharide without any treatment, avoiding the negative environmental effects. Moreover, the one step immobilization-purification simplifies the purification step, which reduces the use of chemicals. Our study provides a nontoxic and inexpensive immobilization strategy for the biocatalytic reaction in food industry.
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TALANTA
·
2019
·
IF 4.916
Li Zhou,Jia Lun,Yanru Liu,Zhen Jiang,Xin Di,Xingjie Guo
In this work, a novel sulfated-β-cyclodextrin (S-β-CD) coated stationary phase was prepared for open-tubular capillary electrochromatography (OT-CEC). The capillary was developed by attaching polydopamine/sulfated-β-cyclodextrin (PDA/S-β-CD) onto the gold nanoparticles (AuNPs) coated capillary which was pretreated with polydopamine. The results of scanning electron microscopy (SEM) and energy dispersive X-ray analysis spectroscopy (EDS) indicated that polydopamine/sulfated-β-cyclodextrin was successfully fixed on the gold nanoparticles coated capillary. To evaluate the performance of the prepared open tubular (OT) column, the enantioseparation was carried out by using ten chiral drugs as model analytes. Under the optimal conditions, salbutamol, terbutaline , trantinterol, tulobuterol, clorprenaline, pheniramine, chlorpheniramine, brompheniramine , isoprenaline and tolterodine were baseline separated with the resolution (Rs) values of 3.25, 1.76, 2.51, 1.89, 3.17, 2.17, 1.99, 1.72, 2.01 and 3.20, respectively. Repeatability of the column was studied, with the relative standard deviations for run-to-run, day-to-day and column-to-column lower than 5.7%.
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Catalysis Science & Technology
·
2018
·Vol. 8
·期 10
·2578-2587
·
IF 5.365
Yanzi Wang,Jing Sun,Haohai Zhang,Zhiping Zhao,Wenfang Liu
Coenzyme regeneration is important for the industrial utilization of oxidoreductase. In this work, reduced nicotinamide adenine dinucleotide (NADH) was regenerated under visible light via a photosensitizer and an electron donor. First, several photosensitizers including 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP), zinc porphyrin (ZnTCPP) and eosin Y (EY) with varied concentrations were compared. Next, using TCPP as the photosensitizer, the type and concentration of the electron donor, pH value and concentration of the buffer system for the reaction were optimized. Following that, TCPP was immobilized onto the surface of various supports for screening. Then, the immobilization conditions were optimized and the photocatalytic performance of silica-attached TCPP was studied. Lastly, the effect of a rhodium mediator on NADH regeneration was evaluated. The results show that the optimum concentration of TCPP, ZnTCPP and EY was 2, 1 and 4 mM, respectively, and the highest NADH yield of the TCPP system was 2.37 and 1.47 times those of the ZnTCPP and EY systems. With TCPP as the photosensitizer, triethanolamine was the most efficient electron donor and its appropriate concentration was 5 mM. The optimal pH value and concentration of the phosphate buffer was 7.0 and 0.05 M. Under these conditions, a high NADH yield of 81.5% was achieved after 60 min. For the supports examined, the thiol-containing silica microspheres coated with polydopamine and polyethyleneimine had the highest loading capacity of TCPP (9.15 mg per g-support). Via sensitization, the NADH yield was 9.64% after 90 min and was upgraded to 22.5% with the addition of the rhodium mediator.
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BIOCHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 3.226
Ye Yang,Siming Wang,Zixin Zhou,Ruiqi Zhang,Hao Shen,Jiayi Song,Ping Su,Yi Yang
The development of novel approaches for preparing the immobilized enzyme reactors with improved reusability and catalytic performance has attracted tremendous interest because of the extensive applications and the high cost of free enzymes. Herein, we describe a mild and versatile method for the preparation of immobilized enzyme reactors by anchoring trypsin on polydopamine (PDA) functionalized magnetic nanoparticles (MNPs) through DNA directed immobilization (DDI). This reactor exhibited prominent reusability and enhanced catalytic efficiency. The specificity constant (k cat /K m , where k cat is the catalytic rate constant) of the reactor was 1.82 s −1 μM −1 , which was approximately 4.7-fold higher than free trypsin. Notably, the immobilized trypsin reactors maintained more than 55% of their initial activity after 70 cycles (in pH 9.0 PBS, 37 °C). The improved activity and reusability were dually benefited from the rigidity and stability of DNA linkers as well as the excellent biocompatibility and cushioning effects of PDA. Given the excellent reusability and high catalytic efficiency of this immobilized trypsin reactors, we believe that this study paves the way for preparing low-cost enzyme reactors for a wide range of applications in biocatalysis, biological diagnosis, and biotechnology.
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RSC Advances
·
2018
·Vol. 8
·期 49
·28032-28040
·
IF 2.936
Xiaofeng Hu,Lixun Deng,Hua Ouyang,Huihu Wang
Graphitic carbon nitride (g-C3N4) nanosheets have been successfully immobilized on diatomite to form a g-C3N4/diatomite hybrid through a facile electrostatic adsorption method and subsequent calcination process. Electron microscopy studies confirm that the surface of the diatomite is tightly covered with g-C3N4 nanosheets. In addition, the characterization results of Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectra (XPS) verify that there is a strong interaction between the g-C3N4 and diatomite components inside the hybrids. The visible light absorption edge of the hybrids exhibits a significant redshift compared with the bare g-C3N4 nanosheets and diatomite, which leads to the improvement of visible light absorption and utilization. The photocatalytic results demonstrated that the photocatalytic performance for methyl orange and phenol degradation using the hybrids as photocatalysts has been obviously improved compared to that of g-C3N4 nanosheets, which may be ascribed to its adsorption/photocatalysis synergistic effect.
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