POLYMER BULLETIN
·
2021
·Vol. 79
·期 9
·7177-7192
·
IF 2.87
Pan Zhaoqun,Chen Mianfeng,Zeng Keling,Kang Yingzi
In this paper, a cyclotetrasiloxane modified with epoxy resin was synthesized via hydrosilylation with 1, 3, 5, 7-tetramethylcyclotetrasiloxane (D4H) and 4-vinyl-1-cyclohexane 1, 2-epoxide (VCHO). The structure of tetramethylcyclotetrasiloxane modified with cyclohexane epoxide (D4H–VCHO) was characterized by Fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (1H-NMR) and gel permeation chromatography (GPC). The effects of feeding methods, feeding ratios, catalyst dosages, reaction temperature and reaction time on the products were investigated. After 4-h reaction with 8 ppm catalyst at 90 °C, D4H–VCHO was obtained with an epoxy value of 0.521 and a refractive index of 1.4920. Then, with 4-methylhexahydrophthalic anhydride as a curing agent and tetrabutylammonium bromide as a catalyst, the obtained D4H–VCHO was cured at 90 °C for 1 h and then 120 °C for another hour. The cured products showed high light transmittance, strong thermal stability, suitable hardness and low water absorption. The glass transition temperature of cured materials was 151.6 °C, indicating the improvement of flexibility. In addition, the introduction of epoxy groups greatly enhanced the adhesion of silicone resins to substrates. The results demonstrated that the epoxy-modified silicone materials could be applied as LED packaging materials.
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Science China-Technological Sciences
·
2021
·Vol. 64
·期 9
·2023-2032
·
IF 3.572
Pang Long,Zhong Wei,Wang QiuBo,Feng HaoHui,Dong HaoNan,Wang Song,Cong HaiLin,Shen YouQing,Yu Bing
Disulfide (DSF) has been proved good anti-tumor effect and even better with coadministration of Cu 2+ . In this work, we report the use of hyaluronic acid (HA) based materials to construct vectors for the delivery of both DSF and Cu 2+ . HA was firstly modified with polyethylene glycol monomethyl ether (mPEG) and polycaprolactone (PCL) to synthesize an amphiphilic polymer (HA-PEG-PCL). DSF could be loaded in the hydrophobic core and Cu 2+ could be cooperated to the negative hydrophilic segment. The Cu 2+ also played a role as crosslinking agent, which prevented DSF leakage prematurely, avoiding the bad side effects to normal tissues. The interaction between HA and CD44 improved the distribution of nanodrugs in tumor cells. When the nanodrugs were delivered to the cancer cell, the acidic micro-environment would separate the Cu 2+ from the surface, leading to the disintegration of the micelles, promoting the release of DSF from the micelle core. The results of in vitro and in vivo experiments showed that the DSF and Cu 2+ co-delivery vector constructed in this work could enhance the antitumor effect and have low biological toxicity.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 29
·期 2
·1824-1835
·
IF 4.223
Chen Yuan,Chen Yuancai
At present, there are many studies on microbial reduction of Pd (II), although few of these studies assess the bacterial toxicity of Pd (II) before and after reduction by microorganisms. In this study, the toxicity of Pd (II) to Bacillus wiedmannii MSM ( B. wiedmannii MSM) was assessed before and after reduction by live B. wiedmannii MSM cells (referred to as “Pd (0)-loaded cells”) and after biosorption by dead B. wiedmannii MSM cells (referred to as “Pd (II)-loaded cells”). B. wiedmannii MSM is a widely occurring, nonpathogenic aerobic bacterium. Compared with Pd (II), the EC 20 , EC 50 , and EC 80 of Pd (0)-loaded cells increased by 77.73-, 112.75-, and 163.91-fold, respectively, while the EC 20 , EC 50 , and EC 80 of Pd (II)-loaded cells increased by only 11.55-, 9.77-, and 8.29-fold, respectively. The sterilization contribution rates of the mechanisms of action of Pd (0)-loaded cells were ranked in the order of: remaining Pd (II) > oxidative stress > physical puncture. Pd (II) was found to increase cell membrane permeability, glutathione S-transferase (GST) enzyme activity, and reactive oxygen species levels in cells and decrease the cell membrane potential. XPS results indicated that Pd (II) increased the content of polysaccharides and peptides and decreased the content of hydrocarbons in cells. These findings reveal the bactericidal mechanism of toxicity of Pd (II) and Pd (0)-loaded cells on Bacillus wiedmannii MSM and provide an environmentally friendly and inexpensive method for Pd (II) detoxification.
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PubMed
高影响因子
ACTA PHARMACOLOGICA SINICA
·
2021
·Vol. 43
·期 5
·1264-1273
·
IF 6.15
Ren Zheng-nan,Yang Jun,Zhang Meng-ya,Huang Yi-wen,Song Dong-xiao,Sun Xun,Pan Li-long,Sun Jia
Acute pancreatitis (AP), an inflammatory disorder of the pancreas, is a complicated disease without specific drug therapy. ( R )-4,6-dimethoxy-3-(4-methoxy phenyl)-2,3-dihydro-1H-indanone [( R )-TML104] is a synthesized analog of the natural product resveratrol sesquiterpenes (±) -isopaucifloral F. This study aimed to investigate the effect and underlying mechanism of ( R )-TML104 on AP. The experimental AP model was induced by caerulein hyperstimulation in BALB/c mice. ( R )-TML104 markedly attenuated caerulein-induced AP, as evidenced by decreased pancreatic edema, serum amylase levels, serum lipase levels, and pancreatic myeloperoxidase activity. In addition, ( R )-TML104 significantly inhibited the expression of pancreatic chemokines C–C motif chemokine ligand 2 and macrophage inflammatory protein-2 and the infiltration of neutrophils and macrophages. Mechanistically, ( R )-TML104 activated AMP-activated protein kinase and induced sirtuin 1 (SIRT1) expression. ( R )-TML104 treatment markedly induced the SIRT1-signal transducer and activator of transcription 3 (STAT3) interaction and reduced acetylation of STAT3, thus inhibiting the inflammatory response mediated by the interleukin 6-STAT3 pathway. The effect of ( R )-TML104 on SIRT1-STAT3 interaction was reversed by treatment with a SIRT1 inhibitor selisistat (EX527). Together, our findings indicate that ( R )-TML104 alleviates experimental pancreatitis by reducing the infiltration of inflammatory cells through modulating SIRT1.
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FIBERS AND POLYMERS
·
2021
·Vol. 22
·期 11
·2972-2978
·
IF 2.153
You Haining,Zhang Qiang,Yan Shuqin,You Renchuan
Chondroitin sulfate (CS) is a naturally derived bioactive macromolecule and has been used to improve the performance of silk fibroin (SF) biomaterials for soft tissue regeneration. However, it is still a challenge to use a chemical-free method to prepare water-insoluble SF/CS scaffolds. Here, a novel all-aqueous process was developed to prepare SF/CS scaffolds with controlled properties. Freezing-annealing treatment was used to induce silk I crystallization of SF to entrap CS macromolecules. It was found that the addition of CS did not prevent silk I crystallization of SF, even with a ratio as high as 10 % addition ratio. With increasing CS content, the water solubility of the scaffolds increased due to insufficient silk I crystals. The physicochemical properties of the scaffolds were evaluated, and the results showed that the water binding capacity and mechanical properties of the SF scaffolds can be effectively regulated by adding only less than 5 % CS content. This study provides a green strategy, including all-aqueous, low temperature, and without the use of toxic chemicals or solvents, to prepare bioactive SF/CS scaffolds for use in tissue engineering.
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CATALYSIS LETTERS
·
2021
·Vol. 151
·期 12
·3437-3450
·
IF 3.186
Bao Er-Peng,Dong Ruichen,Zhang Shuoqing,Li Huan,Zhang Weiguo,Zou Jijun,Xu Qiang
The photocatalysis is a very promising technique to address the serious issues of environmental pollution. Among the common photocatalysts, the graphitic carbon nitride (g-C 3 N 4 ) is widely used for the photodegradation of organic pollutants due to its proper band structure. To further improve the photocatalytic performance of g-C 3 N 4 , a novel composite photocatalyst of Co 3 O 4 /PT-C 3 N 4 has been prepared by using a one-pot calcination method, in which cobalt tetroxide (Co 3 O 4 ) nanoparticles as the cocatalyst are introduced on the surface of rectangular hollow g-C 3 N 4 substrate (PT-Co 3 O 4 ). As a result, the obtained composite photocatalyst (Co3O 4 /PT-C 3 N 4 ) delivers an excellent photodegradation performance for diesel oil under a simulated sunlight, which can improve the separation efficiency of the photo-induced electron–hole pairs. The Co 3 O 4 /PT-C 3 N 4 composite photocatalyst exhibits a high degradation efficiency of 96.27% after 2 h of visible light, which is much higher than that of the PT-C 3 N 4 photocatalyst. Moreover, the composite photocatalyst can still maintain a high photodegradation efficiency after 10 cycles, exhibiting an excellent cyclic stability. The photo-induced carriers generated by the Co 3 O 4 /PT-C 3 N 4 composite photocatalyst follow the Z-scheme heterojunction transfer mechanism. This work gives a fresh idea for the exploration of new high-performance photocatalyst for the treatment of organic environmental pollutants. Graphical Abstract
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MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 4
·1-13
·
IF 5.833
Yang Qiaoli,Deng Sangsang,Xu Jingjing,Farooq Umer,Yang Taotao,Chen Wei,Zhou Lei,Gao Meiying,Wang Shenqi
Yersinia pseudotuberculosis is an enteric bacterium causing yersiniosis in humans. The existing Yersinia pseudotuberculosis detection methods are time-consuming, requiring a sample pretreatment step, and are unable to discriminate live/dead cells. The current work reports a phage-based electrochemical biosensor for rapid and specific detection of Yersinia pseudotuberculosis . The conductive poly(indole-5-carboxylic acid), reduced graphene oxide, and gold nanoparticles are applied for surface modification of the electrode. They possess ultra-high redox stability and retain 97.7% of current response after performing 50 consecutive cycles of cyclic voltammetry.The specific bacteriophages vB_YepM_ZN18 we isolated from hospital sewage water were immobilized on modified electrodes by Au-NH 2 bond between gold nanoparticles and phages. The biosensor fabricated with nanomaterials and phages were utilized to detect Yersinia pseudotuberculosis successfully with detection range of 5.30 × 10 2 to 1.05 × 10 7 CFU mL −1 , detection limit of 3 CFU mL −1 , and assay time of 35 min. Moreover, the biosensor can specifically detect live Yersinia pseudotuberculosis without responding to phage-non-host bacteria and dead Yersinia pseudotuberculosis cells. These results suggest that the proposed biosensor is a promising tool for the rapid and selective detection of Yersinia pseudotuberculosis in food, water, and clinical samples.
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CELLULOSE
·
2021
·Vol. 28
·期 6
·3409-3421
·
IF 5.044
Chen Weixiang,Chen Bo,Lv Rixin,Wu Milian,Zhou Jie,Lu Beili,Huang Biao,Lu Qilin,Tang Lirong
Natural cellulose nanocrystals (CNCs) possess outstanding properties, such as biodegradability, hydrophilicity, large specific surface areas, and are low in cost. A highly stable and sensitive humidity sensor based on a quartz crystal microbalance (QCM) was prepared using CNCs as the sensing film. To investigate the impact of CNCs loading on the sensor performance, a series of humidity-sensitive performance tests, including linearity, response and recovery times, repeatability, hysteresis characteristics, selectivity, and long-term stability tests, was conducted. The experimental results indicated that the humidity sensor with CNCs loading of 2 μg (QCM-2) exhibited excellent logarithmic linearity, high sensitivity (32.35 Hz/% relative humidity (RH)), excellent reversible behavior, and long-term stability at a RH of 11–84%. The contact angle of QCM-2 was 12.5°, revealing its suitable hydrophilicity. Thus, we demonstrate that CNCs are great prospects for potential application in humidity sensors with high performance and low cost. Graphic abstract
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FIBERS AND POLYMERS
·
2021
·Vol. 22
·期 12
·3298-3308
·
IF 2.153
Wen Wen,Zhang Zaixing,Jing Lingxiao,Zhang Tonghua
Due to the structure of hierarchical aligned cellulose fibrils, cotton fabric used in clothing possesses excellent moisture and thermal managements. Such structure yet may retain metabolic excrements and sebum secretions discharged from the human skin, which reproduce microorganisms harmful for human health. However, incorporating the antimicrobial coating into the cotton fabric can sufficiently resist the microorganism growth. In this work, a water-soluble antibacterial coating named N-(4-(allyloxy) benzylidene)-2-(piperazin-1-yl) ethanamine (NABPE) was synthesized to produce a rechargeable and fast sterilization cotton fiber fabric (M-cotton/NABPE). M-cotton/NABPE exhibited a high effective antibacterial activity, and the inhibition ratios against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) were 94 % and 93 %, respectively. Chlorination was performed with sodium hypochlorite solution to form N-Cl bond on the M-cotton/NABPE fabrics, resulting in a high biocidal efficacy of up to 100 % via contact killing for a duration of 5 min. After 25 washing cycles, the antibacterial fabric still maintained an antibacterial rate of 91.95 % and 92.15 % against E. coli and S. aureus , respectively. Furthermore, the fabrics showed integrated properties of excellent UV stability, long-term stability, robust rechargeable biocidal activity (chlorine recharging >5000 ppm) and washing durability. This research provides fundamental insights into the synthesis of the NABPE and prolonged biocidal efficacy of the M-cotton/NABPE, and thereby pave a pathway to incorporate an economic and environmental-friendly antibacterial coating suitable for finishing cotton fabric.
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Nature Communications
·
2021
·Vol. 12
·期 1
·1-11
·
IF 14.919
Wang Jia-Wei,Jiang Long,Huang Hai-Hua,Han Zhiji,Ouyang Gangfeng
The fulfillment of a high quantum efficiency for photocatalytic CO 2 reduction presents a key challenge, which can be overcome by developing strategies for dynamic attachment between photosensitizer and catalyst. In this context, we exploit the use of coordinate bond to connect a pyridine-appended iridium photosensitizer and molecular catalysts for CO 2 reduction, which is systematically demonstrated by 1 H nuclear magnetic resonance titration, theoretical calculations, and spectroscopic measurements. The mechanistic investigations reveal that the coordinative interaction between the photosensitizer and an unmodified cobalt phthalocyanine significantly accelerates the electron transfer and thus realizes a remarkable quantum efficiency of 10.2% ± 0.5% at 450 nm for photocatalytic CO 2 -to-CO conversion with a turn-over number of 391 ± 7 and nearly complete selectivity, over 4 times higher than a comparative system with no additional interaction (2.4%±0.2%). Moreover, the decoration of electron-donating amino groups on cobalt phthalocyanine can optimize the quantum efficiency up to 27.9% ± 0.8% at 425 nm, which is more attributable to the enhanced coordinative interaction rather than the intrinsic activity. The control experiments demonstrate that the dynamic feature of coordinative interaction is important to prevent the coordination occupancy of labile sites, also enabling the wide applicability on diverse non-noble-metal catalysts.
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MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 5
·1-10
·
IF 5.833
Gu Ying,Hu Yuanling,Zhang Fuyuan,Yi Lunzhao,Shang Ying,Ren Dabing,Ge Zhenhua
A glucose (Glu) sensor was designed by introducing synthetic cyclic peptides (CPs) as recognition receptors and Au nanoparticles assisted graphitic carbon nitride (AuNPs/g-C 3 N 4 ) for electrochemiluminescence (ECL) enhancement. The synthetic CP receptor (cyclo-[−CNDNHCRDNDC−]) with natural active center of Glu binding protein can mimic the interactions between Glu and Glu binding protein to specifically capture Glu. The AuNPs were reduced on g-C 3 N 4 and formed a new nanohybrid that can be applied as an ECL emitter. The AuNPs/g-C 3 N 4 effectively ameliorated the ECL response of bare g-C 3 N 4 . The ECL enhancement mechanism was theoretically speculated through computer simulation. Glu quantification was conducted by recording ECL shifts induced by the binding of Glu to CPs. The linear detection range of the fabricated CPs-based ECL sensor was 1 to 100 mmol L −1 , and the detection limit (LOD) was 0.57 nmol L −1 (S / N = 3). The CP-based ECL sensor also showed good specificity, repeatability, stability, and favorable recoveries in sample analysis. This work offer a promising analytical method for Glu assay in clinical diagnostics and bioprocess monitoring. Graphical abstract
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CHEMICAL PAPERS
·
2021
·Vol. 75
·期 7
·3679-3693
·
IF 2.097
Cheshari Emily C.,Ren Xiaohui,Li Xin
Carbamate pesticides are popularly used in agriculture due to their relatively low toxicity and their more degradable nature compared to organophosphates. Resultant residues pose a threat to human and animal health, aquatic systems and wildlife. Carbaryl and thiodicarb are used to control pests in a variety of agricultural crops. Monitoring the level of these pesticides in the environment is crucial in ensuring environmental safety. Multi-template imprinted polymers combined with surface enhanced Raman spectroscopy (SERS) are attractive for sensitive and effective multiple analyte detection for application in pesticide residue studies in environmental matrices. A core–shell Ag-dual template molecularly imprinted polymer (MIP) composite was synthesized and evaluated in this study. Computational design was used to study intermolecular interactions in the pre-polymerization mixture between methylacryamide (MAM) (functional monomer) and the templates carbaryl (CBL) and thiodicarb (TDC). The interaction between the computer simulated template-functional monomer complexes was evaluated by examining the hydrogen bonds to provide insights on the observed binding performance of the dual imprinted polymer. The MIP was then synthesized and its binding properties towards CBL and TDC investigated experimentally. More so, we compared the performance of the mono-template MIP materials and the dual-template MIP material in detection of the templates. The experimental results corroborate the computer simulation results and reveal that CBL has higher adsorption capacity as supported by higher number of hydrogen bonds in the template monomer complex. Therefore, the study presents a cost-effective approach that utilizes a dual-template imprinted polymer for detection of carbamate pesticide residues.
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