Bioresources and Bioprocessing
·
2018
·Vol. 5
·期 1
·1-8
·
IF 0
Gao Zhen,Yi Yunfei,Zhao Jia,Xia Yongyang,Jiang Min,Cao Fei,Zhou Hua,Wei Ping,Jia Honghua,Yong Xiaoyu
Background Laccase, a multicopper oxidase that catalyzes the oxidation of phenols, aromatic amines, and benzenethiols, has attracted much attention in applications of organic synthesis, bioremediation, and pulp/textile bleaching. However, free laccases cannot be recycled and are easily inactivated in diverse environmental conditions. Enzyme immobilization is a promising strategy to improve stability, resistance to extreme conditions, and reusability of laccase. Results In this study, amino-functionalized magnetic Fe 3 O 4 nanoparticles were synthesized for co-immobilization of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and laccase by glutaraldehyde cross-linking method. The magnetic nanoparticles were characterized with FTIR, XRD and VSM. Cyclic voltammetry was carried out to verify electrochemical behaviors of the co-immobilized laccase and TEMPO nanoparticles. When the co-immobilized laccase and TEMPO nanoparticles were used to decolorize acid fuchsin, the maximum decolorization rate of 77.41% was obtained with the ratio of TEMPO to laccase being 0.3 mM/g:120 U/g. Conclusion The co-immobilized nanoparticles retained above 50% residual activity after eight cycles of operation, which presented an approach to develop a co-immobilized laccase and mediator system for potential industrial application.
研究领域:
生物化学
·
环境科学
✓ 已验证
DOI
CELLULOSE
·
2017
·Vol. 24
·期 11
·4831-4844
·
IF 3.417
Chen Yufei,Geng Biyao,Ru Jing,Tong Congcong,Liu Hongzhi,Chen Jinzhou
Bamboo, softwood, and hardwood pulp fibers were used as starting materials to prepare TEMPO-oxidized nanofibrillated cellulose (TO-NFC) dispersions. The resulting TO-NFC dispersions were then used to fabricate cellulose nanopapers and to coat poly(lactic acid) (PLA) films. The chemical and morphological characteristics of the dispersions together with the physical properties of the resultant nanopaper and PLA films were systematically compared. The maximum degree of oxidation was achieved for the bamboo pulp fiber. Transmission electron microscopy micrographs revealed that the oxidized pulp fibers were successfully disintegrated into cellulose nanofibrils with an average width of 5–6 nm. However, bamboo-derived TO-NFC was more densely entangled and crimped, with a heterogeneous distribution in width. It was further revealed that morphologies of the obtained TO-NFC may arise from the organizational structure of microfibrils in the cellulose fibers rather than the presence of hemicelluloses or the pulping process. The PLA films coated with a thin layer of TO-NFC from the bamboo pulp exhibited the highest oxygen-barrier property, which was even slightly higher than commercial ethylene–vinyl alcohol copolymer film, known for its high oxygen-barrier functionality.
研究领域:
材料科学
·
林业工程
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Wangfang Deng,Yidong Zhang,Meiyan Wu,Chao Liu,Guang Yu,Bin Li,Yanjun Tang
2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)/NaBr/NaClO catalytic oxidation system is a commonly used method to prepare carboxylated cellulose nanofibrils (TOCNF), but the traditional reaction system is relatively time consuming with high production cost. Herein, a facile and clean process of lithium bromide trihydrate (LBTH) pretreatment of hardwood dissolving pulp (HDP) was conducted, which promoted the reaction and reduced the use of chemicals for TEMPO oxidation. Characterizations verified that the LBTH pretreatment could significantly improve the efficiency of the subsequent TEMPO oxidation of HDP. Particularly, the obtained TEMPO-oxidized cellulose nanofibrils (TOCNF) had highly amorphous structure, the carboxyl content (1.06 mmol/g) of the obtained TOCNF with LBTH pretreatment for 5 min could increase by 58%, and the corresponding oxidation time was shortened by 57%, compared to the unpretreated HDP. Moreover, the fabricated TOCNF with increased carboxyl content exhibited strong ability to stabilize high internal phase Pickering emulsions (HIPPEs) with analogous average particle sizes. Additionally, LBTH solvent could be easily recovered, and the recycling does not affect the effectiveness of LBTH pretreatment. Compared to the unpretreated HDP, the operation cost of TEMPO-mediated oxidation could be reduced by 31% with the LBTH pretreatment. This work has potential to boost the commercial production and application of TOCNF and nanocellulose-based materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2016
·
IF 4.836
Nan Zhang,Guo-Long Zang,Chen Shi,Han-Qing Yu,Guo-Ping Sheng
This study describes the preparation of a novel adsorbent based on cellulose nanofibrils by first TEMPO mediated oxidation and then PEI grafting (TOCN-PEI) for heavy metal removal. FTIR results demonstrated the successful introduction of the adsorption functional groups (carboxyl and amino groups), and the elemental analysis and acid base titration were used to quantify the contents of these introduced groups. The kinetics curve suited the pseudo-second-order model better and the equilibrium data well fitted the Langmuir model, with the maximum Cu(II) uptake of 52.32 mg g −1 . Kinetic study showed that the PEI grafting increased the initial adsorption rate of the TOCN-PEI compared with the adsorbents without PEI. Thermodynamic study was carried out through isothermal titration calorimetry (ITC) measurement and the binding reaction was found to be exothermic and driven by enthalpy change. The adsorption process by TOCN-PEI was pH dependent, and decreasing pH would lead to desorption of Cu(II) ions, thus make the reuse of the absorbent more convenient through adsorption-desorption cycles.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Baolong Huo,Man Du,Ao Shen,Mengwen Li,Yaru Lai,Xue Bai,Aijun Gong,Leqiu Fang,Yunxu Yang
A highly selective and sensitive fluorescence “light-up” probe PTH for ClO − has been developed, which is designed by a new strategy based on TEMPO-oxidation for the first time. PTH exhibits excellent properties including quick response (within 2 min), lower detection limit (63.7 nM), good linearity ( R 2 = 0.9863) and specific selectivity. More importantly, its application of detection ClO- in real samples has also been achieved.
研究领域:
分析化学
·
生物医学
✓ 已验证
产品关联
DOI
高影响因子
BIOSENSORS & BIOELECTRONICS
·
2024
·
IF 10.7
Nan Ma,Shuqi Wang,Mengyuan Liu,Hao Zhu,Qianzuo Liu,Jinming Kong,Ting Zhang
Assembling functional molecules on the surface of an enzyme electrode is the most basic technique for constructing a biosensor. However, precise control of electron transfer interface or electron mediator on the electrode surface remains a challenge, which is a key step that affects the stability and sensitivity of enzyme-based biosensors. In this study, we propose the use of controllable free radical polymerization to grow stable 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) polymer as electron mediator on enzyme surface for the first time. Through scanning electron microscopy (SEM), Raman spectroscopy , electrode surface coverage measurement, static contact angle (SCA), and a series of electrochemical methods , it has been demonstrated that the TEMPO-based enzyme electrode exhibits a uniform hydrophilic morphology and stable electrochemical performance. Furthermore, the results show that the sensor demonstrates high sensitivity for detecting glucose biomolecules in artificial sweat and serum. Attributing to the quantitative and controllable radical polymerization of TEMPO redox assembled enzyme electrode surface, the as-proposed biosensor providing a use, storage, and inter-batch sensing stability, providing a vital platform for wearable/implantable biochemical sensors .
研究领域:
生物化学
·
材料科学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2021
·
IF 4.126
Tianyou Chen,Wei Xiao,Zihao Wang,Pengfei Gan,Changfeng Yi,Zushun Xu
Noncovalent immobilization of discrete molecular species on polymer supports is a unique approach to engineer multifunctional cooperative catalysts. Here we devise a modular strategy for the construction of polymer-supported Cu/2,2,6,6-tetramethyl-1-piperidine-N-oxyl (TEMPO) catalytic systems by using hydrophobic interactions and aromatic stacking interactions. Polymer-supported Cu/TEMPO catalysts prepared by nanoprecipitation exhibit excellent catalytic activities for aerobic oxidation of benzyl alcohol, which can be tailored by the type of aromatic moieties, effective constituent ratios, and polymer compositions. We found that strong aromatic stacking interactions and the use of pyrene-containing polymers are crucial to enhance cooperativity. This modular strategy is promising for the immobilization of multifunctional cooperative catalysts with excellent catalytic activities and has potential for the engineering of other heterogeneous multifunctional catalysts.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 10
·2246
·
IF 4.2
Shasha Liu,Mei Sun,Can Wu,Kaixuan Zhu,Ying Hu,Meng Shan,Meng Wang,Kai Wu,Jingyi Wu,Zongli Xie,Hai Tang
Dye/salt separation has gained increasing attention in recent years, prompting the quest to find cost-effective and environmentally friendly raw materials for synthesizing high performance nanofiltration (NF) membrane for effective dye/salt separation. Herein, a high-performance loose-structured NF membrane was fabricated via a simple vacuum filtration method using a green nanomaterial, 2,2,6,6-tetramethylpiperidine-1-oxide radical (TEMPO)-oxidized cellulose nanofiber (TOCNF), by sequentially filtrating larger-sized and finer-sized TOCNFs on a microporous substrate, followed by crosslinking with trimesoyl chloride. The resulting TCM membrane possessed a separating layer composed entirely of pure TOCNF, eliminating the need for other polymer or nanomaterial additives. TCM membranes exhibit high performance and effective dye/salt selectivity. Scanning Electron Microscope (SEM) analysis shows that the TCM membrane with the Fine-TOCNF layer has a tight layered structure. Further characterizations via Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed the presence of functional groups and chemical bonds of the crosslinked membrane. Notably, the optimized TCM-5 membrane exhibits a rejection rate of over 99% for various dyes (Congo red and orange yellow) and 14.2% for NaCl, showcasing a potential candidate for efficient dye wastewater treatment.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2022
·
IF 9.224
Feng-Ping Wang,Jing-Jing Li,Yu Zhang,Mei-Yan Sun,Li Li,Fazli Wahid,Yan-Yan Xie,Shiru Jia,Wenchao Li,Cheng Zhong
The cellulose dissolution is conducive to converting it into higher value-added cellulose products. However, conventional cellulose solvents possess several drawbacks, such as high cost and harsh reaction conditions. In this study, a new strategy that combined 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation and a zincate–NaOH system was proposed for cellulose solubilization. The results showed that TEMPO-mediated oxidation increased the hydrophilicity of cellulose, destroyed the surface and amorphous areas of the fiber, and facilitated solvent access to its crystalline regions in the subsequent treatment. Zn(OH)42– can be used as a stabilizer to prevent cellulose from agglomeration and form strong hydrogen bonds with cellulose to enhance cellulose dissolution. All-cellulose composites with antibacterial properties were prepared from cellulose using a partial dissolution method at room temperature. This preparation is simple and low cost, laying the foundation for its application in biomedicine.
研究领域:
化学工程
·
材料科学
·
生物技术
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF PHARMACEUTICS
·
2021
·
IF 5.875
Junjun Li,Rong Du,Qiong Bian,Danping Zhang,Siqian Gao,Anran Yuan,Xiaoying Ying,Youqing Shen,Jianqing Gao
During the occurring of cutaneous trauma, increasing oxidative stress response in wound site retards the progress of proliferation phase, impeding sequent efficient wound repair. At the same time, high-quality healing also requires adequate new blood vessels in order to furnish the wound site with a nutrient and oxygen-sufficient environment. Here we synthesized a novel hyaluronic acid (HA) material modified with a peroxidation inhibitor 2,2,6,6-tetramethylpiperidinyloxy (ATEMPO) for prevention of excessive reactive oxygen species (ROS) and promotion of angiogenesis after full-thickness skin excision in rats. Amines in ATEMPO attaching with carbonyls in HA chains was fabricated through N-acylation. The HA-g-TEMPO exerted a ROS-scavenging and angiogenesis-promoting function in vitro . In acute wound rat model, the wound closure efficacy was significantly improved to almost 55% at day 6 in comparison to 49% of HA, and wound sites in initial wound phase was also narrowed down sharply. Moreover, initially formed blood vessels were found in wound sites, further proved the angiogenesis-promoting function of HA-g-TEMPO. More interestingly, wound sites demonstrated an exciting regenerative healing effect which was characterized by marked skin appendages as well as reduced scarring. Therefore, this strategy showed a promising future that could be considered as a reliable and effective method to cutaneous wound healing.
研究领域:
药学
·
生物医学工程
·
组织工程
✓ 已验证
DOI
PubMed
高影响因子
FIBERS AND POLYMERS
·
2020
·Vol. 21
·期 6
·1251-1258
·
IF 1.797
Liang Huazhe,Cao Meng,Yang Desheng,Sun Tingting,Chu Xiaomeng,Liu Shaojie
A series of polyamidoamine (PAMAM) immobilized TEMPO macromolecular catalysts were prepared by condensation reduction reactions between carbonyl groups in 4-O-TEMPO and primary amines in PAMAM. The macromolecular catalyst and NaBr/NaClO were used as catalytic system for selective oxidation of cellulose in aqueous medium. Effects of various factors, such as TEMPO loading ratios and PAMAM generations, were studied on the catalytic performances. Compared with free TEMPO, the macromolecular catalyst with less than 50 % TEMPO loading ratio had a higher reaction rate in the initial stage of the reaction. Especially, the reaction rate of G1.0 PAMAM with 30 % TEMPO loading ratio was comparable to free TEMPO in the whole reaction process. Its cellulose oxidation degree (or catalytic activity) was also equivalent to the level of free TEMPO. Interestingly, the cellulose depolymerization degree of macromolecular catalyst was not affected by the cellulose oxidation degree and was lower than that of free TEMPO. The macromolecular catalyst could be recycled efficiently by the combination of supernatant circulation and salting-out extraction, and the recycling performance was excellent.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Storage
·
2025
·
IF 9.8
Shidong Song,Junjie Ma,Huanlei Zhao,Phumlani F. Msomi,Jiahao Ren,Yanan Liu,Run Ma,Wanyu Ye
In terms of stability and safety, quasi-solid-state lithium-oxygen batteries (QSSLOBs) outperform traditional liquid LOBs. However, using redox mediators (RMs) in QSSLOBs requires unique strategy to inhibit the shuttle effect of RMs. In this work, a PEO-based oxygen electrode with anchored 4-OH-TEMPO (4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy) RM (referred to as TEMPO-PEO) is developed via hydrogen-bonding interaction for QSSLOBs. The TEMPO-PEO oxygen electrode can perform both significant mediation function and oxygen reduction reaction (ORR) activity. The QSSLOB using TEMPO-PEO electrode achieves a low discharge/charge voltage gap of 0.9 V and a high Coulombic efficiency of 96.8 %, which is significantly superior to the counterparts using TEMPO solution (TEMPO cell) or unanchored TEMPO (TEMPO+PEO cell). On this basis, the TEMPO-PEO cell achieves an unprecedented cycle performance for 320 cycles under the limited capacity of 300 mAh g −1 , overwhelmingly outperforming the counterpart cells that only deliver 63 cycles (TEMPO cell) and 119 cycles (TEMPO+PEO cell), respectively. After cycling, the TEMPO RM can still be well retained on TEMPO-PEO oxygen electrode and no significant side product is formed on the after-cycled Li anode of TEMPO-PEO cell, explicitly demonstrating a strong and consistent anchoring effect on suppressing the shuttling of RM species.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）