NEW JOURNAL OF CHEMISTRY
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2017
·Vol. 41
·期 16
·8399-8406
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IF 3.269
Longgang Wang,Qinghua Yang,Yanshuai Cui,Dawei Gao,Jianxin Kang,Haotian Sun,Linlin Zhu,Shengfu Chen
The development of stable and biocompatible gold nanoparticles has been drawing great interest. Dendrimers could be used as templates to entrap gold nanoparticles. Herein, dendrimer templates were prepared by the modification of generation 5 polyamidoamine (G5 PAMAM) dendrimers with maleic anhydride and cysteamine. Then modified dendrimer-encapsulated gold nanoparticles (Au-G5MC NPs) were formed by incubation of the templates with chloroauric acid and reduction with sodium borohydride. The resulting Au-G5MC NPs showed high stability, biocompatibility, and catalytic efficiency in water, which is ascribed to the single zwitterionic layer composed of amine and carboxyl groups. The single zwitterionic layer was shown to provide the Au-G5MC NPs with excellent stability in both phosphate-buffered saline and fibrinogen solutions. The mixed solution of Au-G5MC NPs with fibrinogen remained stable within 24 h, while the mixed solution of G5 PAMAM dendrimer-entrapped gold nanoparticles (Au-G5 NPs) with fibrinogen formed obvious aggregates immediately. Au-G5MC NPs displayed little cytotoxicity (>90% cell viability) against HeLa cells up to 100 μg mL−1, while Au-G5 NPs showed obvious cytotoxicity (60% cell viability). In addition, Au-G5MC NPs displayed high catalytic efficiency for the reduction reaction of 4-nitrophenol (4-NP) in water. This method can be used to prepare a variety of highly stable, biocompatible, and efficient dendrimer-encapsulated catalysts.
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Acta Biomaterialia
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2017
·
IF 6.319
Huicong Zhou,Huanjiao Sun,Shixian Lv,Dawei Zhang,Xuefei Zhang,Zhaohui Tang,Xuesi Chen
Traditional chemotherapy strategy exists undesirable toxic side-effects to normal tissues due to the low selectively to cancer cells of micromolecule cytotoxic drugs. One considered method to realizing the targeted delivery and increasing the specificity to tumor tissues of the cytotoxic drug is to transporting and discharging it through an environment-sensitive mechanism. In this study, a novel enzyme-sensitive polymer-doxorubicin conjugate was designed to delivery chemotherapeutic drug in a tumor-specific behavior and selectively activated in tumor tissue. Briefly, doxorubicin (DOX) was conjugated to carboxyl-terminated 4-arm poly(ethylene glycol) through a tetrapeptide linker, alanine-alanine-asparagine-leucine (AANL), which was one of the substrates of legumain , an asparaginyl endopeptidase that was found presented in plants, mammals and also highly expressed in human tumor tissues. Hereinafter, the polymer-DOX conjugate was termed as 4-arm PEG-AANL-DOX. Dynamic laser scattering (DLS) and transmission electron microscopy (TEM) measurements indicated that the 4-arm PEG-AANL-DOX could self-assemble into micelles in aqueous solution. Drug release and in vitro cytotoxicity studies revealed that the 4-arm PEG-AANL-DOX could be cleaved by legumain. Ex vivo DOX fluorescence imaging measurements demonstrated that the 4-arm PEG-AANL-DOX had an improved tumor-targeting delivery as compared with the free DOX·HCl. In vivo studies on nude mice bearing MDA-MB-435 tumors revealed that the 4-arm PEG-AANL-DOX had a comparable anticancer efficacy with the free DOX·HCl but without DOX-related toxicities to normal tissues as measured by body weight change and histological assessments, indicating that the 4-arm PEG-AANL-DOX had an improved therapeutic index for cancer therapy. Statement of Significance Herein we describe the construction of a novel tumor environment-sensitive delivery system through the instruction of a legumain-cleavable linkage to a polymer-DOX conjugate (4-arm PEG-AANL-DOX). This particular design strategy allows for polymer-DOX conjugates to be delivered in a tumor-specific manner and selectively activable in tumor microenvironment so that it can combine the advantages of tumor-specific delivery and tumor intracellular microenvironment-triggered release systems.
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Inorganic Chemistry Frontiers
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2016
·Vol. 3
·期 5
·663-670
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IF 4.532
Weiqiang Li,Xiao Ge,Hao Zhang,Qianqian Ding,Hualin Ding,Yunxia Zhang,Guozhong Wang,Haimin Zhang,Huijun Zhao
Ideally, a superior catalyst should possess high speed, selectivity and stability. However, it is difficult to holistically achieve high speed, selectivity and stability catalysis with modest configured catalyst structures. This work reports a new pre-shell/post-core approach combined with a laser ablation treatment strategy to fabricate a sophisticated catalyst architecture configured with a hollow mesoporous SiO2 (hm-SiO2) sphere shell and multiple encapsulated Ag nanoparticle (NP) yolks (Ag@hm-SiO2). Each Ag@hm-SiO2 nanosphere encapsulates 5–10 Ag NP yolks with an average size of 20 nm, in which the content of silver is about 3.6 wt% based on the inductively coupled plasma measurement. To further enhance the catalytic activity, a laser ablation treatment strategy is innovatively utilized to reduce the sizes of the encapsulated Ag NP yolks and increase their numbers. The catalytic reduction of 4-nitrophenol (4-NP) is used to evaluate the catalytic performance of the fabricated Ag@hm-SiO2 catalyst architecture before and after laser ablation treatment. The laser ablation treated Ag@hm-SiO2 nanospheres demonstrate a three-fold increased catalytic activity towards 4-NP reduction with excellent stability. Such superior catalytic performance could be attributed to the unique structural features of the Ag@hm-SiO2 architecture, in which the mesopore shell provides not only readily accessible pathways for fast transport of reactants to the encapsulated Ag NPs but also an effective protective shield for the encapsulated Ag NPs.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2017
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IF 3.359
Yaoping Guo,Zequan Zeng,Yulin Li,Zhanggen Huang,Jieyang Yang
In-situ S-doped activated carbon (ACS) was prepared and used as a heterogeneous catalyst to activate persulfate (PS) for 4-chlorophenol (4CP) oxidation. The effects of several operation parameters, including PS concentration, initial pH, ACS dosage, and reaction temperature, on 4CP degradation were investigated in detail via batch experiments. Results show that ACS exhibited excellent catalytic activity for PS activation and a complete 4CP degradation as well as 65.3% COD removal can be achieved in 170 min at 25 °C with ACS dosage of 0.1 g/L, PS/4CP molar ratio of 24/1 and initial pH of 4.4. The biodegradability was greatly improved after a 170 min reaction. Quenching tests reveal that SO 4 - was the dominant active species taking part in the degradation of 4CP. Based on the stability tests and the corresponding characterizations of ACS before and after use, it was speculated that the loss of the specific surface area and the change of the surface chemistry led to the significant deactivation of ACS. Meanwhile, a possible mechanism of PS activation on ACS was proposed.
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ENERGY & FUELS
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2016
·
IF 2.835
Qiang Lu,Xiao-ning Ye,Zhi-bo Zhang,Min-Shu Cui,Hao-qiang Guo,Wei Qi,Chang-qing Dong,Yong-ping Yang
Fast pyrolysis of bagasse catalyzed by activated carbon (AC) at low temperatures offered a new and promising way to produce the valuable 4-ethyl phenol (4-EP) compound in high selectivity. In this study, the technique of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was first applied to investigate several factors on the 4-EP production, including biomass type, fast pyrolysis temperature, AC-to-bagasse ratio, and catalytic pattern (in situ or ex situ catalysis). Moreover, fast pyrolysis experiments by using AC catalyst were conducted in a lab-scale setup to quantitatively determine the pyrolytic products. The experimental results indicated that, among these five herbaceous biomass materials, bagasse was the best material to produce 4-vinylphenol (4-VP) from the noncatalytic process and 4-EP from the catalytic fast pyrolysis process, respectively. 4-VP and its precursors could be catalytically hydrogenated into 4-EP with high selectivity under the catalysis of AC catalyst. Both catalytic pyrolysis temperature and AC-to-bagasse ratio affected the 4-EP selectivity significantly, whereas the catalytic pattern had minor effects on the 4-EP production. The highest yield of 4-EP from bagasse in Py-GC/MS experiments was 2.13 wt %, obtained at the pyrolysis temperature of 300 °C and AC-to-bagasse ratio of 4 from the in situ catalytic pattern. Moreover, lab-scale fast pyrolysis of bagasse catalyzed by AC catalyst obtained the maximal 4-EP yield of 2.49 wt %, with the selectivity of 10.71%.
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International Journal of Medical Sciences
·
2017
·
IF 2.399
Lin Yu,Xiaofeng Wu,Min Chen,Huarong Huang,Yan He,Huaqian Wang,Dongli Li,Zhiyun Du,Kun Zhang,Susan Goodin,Xi Zheng
Background : Docetaxel is the first-line treatment for castration-resistant prostate cancer (CRPC). The limited survival benefit associated with the quick emergence of resistance and systemic toxicity diminishes its efficacy in high-dose monotherapy. YK-4-279 is a small molecule inhibitor of ETV1 that plays an important role in the progression of prostate cancer. The aim of this study was to evaluate the hypothesis that the combination of docetaxel and YK-4-279 will have a synergistic effect on inhibiting growth and accelerating apoptosis in human prostate cancer cells. Methods : Cell growth assessed using CCK-8 and trypan blue exclusion assays. Cell apoptosis was determined by morphological assessment in cells stained with propidium iodide. Standard scratch migration and Matrigel-coated transwell invasion assays were used to assess cell migration and invasion, respectively. Western blotting was used to investigate the levels of ETV1, AR, PSA, p-STAT3, survivin, Bcl-2, and p-Akt in prostate cancer cells. Results : The combination of low-dose docetaxel and YK-4-279 synergistically inhibited growth and induced apoptosis in human prostate cancer cells. The combination also more efficiently suppressed the migration and invasion of LNCaP and PC-3 cells. The combination of low-dose docetaxel and YK-4-279 caused a stronger decrease in the levels of ETV1, AR, PSA, p-STAT3, survivin, Bcl-2, and p-Akt in LNCaP cells and of p-Akt, Bcl-2, and p-STAT3 in PC-3 cells compared with either drug alone. Conclusions : These data suggest that the combination of docetaxel and YK-4-279 may be an effective approach for inhibiting the growth and metastasis of prostate cancer. This could permit a decrease in the docetaxel dose necessary for patients with CRPC and thereby lower its systemic toxicity.
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CHEMISTRY OF MATERIALS
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2016
·
IF 9.407
Jie Fu,Qingwen Tian,Zhengji Zhou,Dongxing Kou,Yuena Meng,Wenhui Zhou,Sixin Wu
Additional elements in the Cu2ZnSn(S,Se)4 (CZTSSe) absorber layers can play a crucial role in improving the performance of thin film solar cells. In this paper, a significant performance enhancement of CZTSSe thin film solar cells was achieved by the partial substitution of the Zn2+ cation with Cd2+. A small amount of Cd2+ can be successfully incorporated into the host lattice of CZTSSe to form a homogeneous Cu2Zn1–xCdxSn(S,Se)4 (CZCTSSe) alloy material. We demonstrated that the crystal growth and the band gap of CZCTSSe thin films are affected by the Cd doping level. Additionally, the impact of Cd content on the space-charge density (Nc-v) and the depletion width (Wd) of CZCTSSe solar cells was systematically investigated. By this cation substitution approach, the power conversion efficiency of the solar cells based on the CZCTSSe absorber was successfully increased from 5.41 to 8.11% for the optimal composition (x = 5%).
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2016
·Vol. 408
·期 25
·6945-6956
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IF 3.125
Kumar Saroj,Kumar Dileep,Ahirwar Rajesh,Nahar Pradip
Bioconjugation and functionalization of polymer surfaces are two major tasks in materials chemistry which are accomplished using a variety of coupling agents. Immobilization of biomolecules onto polymer surfaces and the construction of bioconjugates are essential requirements of many biochemical assays and chemical syntheses. Different linkers with a variety of functional groups are used for these purposes. Among them, the benzophenones, aryldiazirines, and arylazides represent the most commonly used photolinker to produce the desired chemical linkage upon their photo-irradiation. In this review, we describe the versatile applications of 4-fluoro-3-nitrophenyl azide, one of the oldest photolinkers used for photoaffinity labeling in the late 1960s. Surprisingly, this photolinker, historically known as 1-fluoro-2-nitro-4-azidobenzene (FNAB), has remained unexplored for a long time because of apprehension that FNAB forms ring-expanded dehydroazepine as a major product and hence cannot activate an inert polymer. The first evidence of photochemical activation of an inert surface by FNAB through nitrene insertion reaction was reported in 2001, and the FNAB-activated surface was found to conjugate a biomolecule without any catalyst, reagent, or modification. FNAB has distinct advantages over perfluorophenyl azide derivatives, which are contemporary nitrene-generating photolinkers, because of its simple, single-step preparation and ease of thermochemical and photochemical reactions with versatile polymers and biomolecules. Covering these aspects, the present review highlights the flexible chemistry of FNAB and its applications in the field of surface engineering, immobilization of biomolecules such as antibodies, enzymes, cells, carbohydrates, oligonucleotides, and DNA aptamers, and rapid diagnostics.
An overview of the FNAB-engineered activated polymer surfaces for covalent ligation of versatile biomolecules
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Synthetic and Systems Biotechnology
·
2024
·
IF 4.4
Ming Zhao,Mengkai Hu,Rumeng Han,Chao Ye,Xiangfei Li,Tianwen Wang,Yan Liu,Zhenglian Xue,Kun Liu
The production of androst-4-ene-3,17-dione (AD) by the steroidal microbial cell factory requires transcription factors (TFs) to participate in metabolic regulation. However, microbial cell factory lacks effective TFs that can respond to AD in its metabolic pathway. Additionally, finding and obtaining natural TFs that specifically respond to AD is a complex and onerous task. In this study, we devised an artificial TF that responds to AD, termed AdT, based on structure-guided molecular dynamics (MD) simulation. According to MD analysis of the conformational changes of AdT after binding to AD, an LBD in which the N - and C -termini exhibited convergence tendencies was used as a microswitch to guide the assembly of a DNA-binding domain lexA, a linker (GGGGS) 2 , and a transcription activation domain B42 into an artificial TF. As a proof of design, a AD biosensor was designed and constructed in yeast on the basis of the ligand-binding domain (LBD) of hormone receptor. In addition, the transcription factor activity of AdT was increased by 1.44-fold for its variant F320Y. Overall, we created non-natural TF elements for AD microbial cell factory, and expected that the design TF strategy will be applied to running in parallel to the signaling machinery of the host cell.
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SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2017
·
IF 4.784
Shoushuai Gao,Yi Zhang,Jianping Ao,Shuping Lin,Zhaojing Zhang,Xiuling Li,Dongxiao Wang,Zhiqiang Zhou,Guozhong Sun,Fangfang Liu,Yun Sun
The direction of Se-Mo-Se sheets to the Mo film is crucial for the thickness of Mo(S,Se) 2 and the electrical conductivity , so as the back contact of Cu 2 ZnSn(S,Se) 4 solar cells. In this study, the preferred orientation of Mo(S,Se) 2 film changes from (100) peak to (103) peak, i.e. from perpendicular to the substrate to tilted to the substrate for Se-Mo-Se sheets as the roughness decrease of Mo back contact layer. The Se vapor can easily diffuse through the channels between Se-Mo-Se sheets when the formed Mo(S,Se) 2 layer is (100) peak preferred with Se-Mo-Se sheets perpendicular to the substrate, and thus excessively thick Mo(S,Se) 2 will be formed. Whereas, the Se-Mo-Se sheets are tilted to substrate when the preferred orientation of Mo(S,Se) 2 is (103) peak. The tilted Se-Mo-Se sheets can act as a natural Se diffusion barrier to suppress the Se vapor diffusion through the already formed Mo(S,Se) 2 layer to further selenize the remaining Mo film, and also can provide a good electrical conductivity. As a result, the thickness of Mo(S,Se) 2 sharply decreased from 1500 nm to 200 nm with the surface morphology change of Mo back contact, which resulting in the decrease of series resistance of Cu 2 ZnSn(S,Se) 4 solar cells from 2.94 Ω cm 2 to 0.49 Ω cm 2 , and the increase of conversion efficiency of Cu 2 ZnSn(S,Se) 4 solar cells from 6.98% to 9.04%.
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ACS Applied Nano Materials
·
2024
·
IF 5.3
Liming Yang,Yanjun Cui,Bing Hu,Qian Yang,Xia Xu
Perovskite quantum dots (PQDs) offer high photoluminescence quantum yields. However, their poor stability and aqueous-quenching of fluorescence limit their wider application, especially in biochemical detection. In this work, a simple and highly successful coating strategy was used to encapsulate Mn2+-doped CsPbCl3 PQDs in poly(ethylene glycol) (PEG), effectively increasing the water stability of PQDs. After dispersion in deionized water for 25 days, the CsPbCl3/Mn2+/PEG nanocrystals (NCs) retained 40% of their initial fluorescence intensity. In addition, due to the FRET mechanism, 4-nitrophenol (4-NP) can effectively quench the fluorescence of CsPbCl3/Mn2+/PEG NCs. Therefore, utilizing the excellent water stability of CsPbCl3/Mn2+/PEG NCs and their interaction with 4-NP, a fast and conservative fluorescent probe can be established, which can perform highly selective and ultrasensitive quantitative detection of 4-NP in aqueous solutions. In addition, the molecular weight of PEG used for encapsulation, the fluorescence intensity of CsPbCl3/Mn2+/PEG NCs, and the detection range for 4-NP vary. Fortunately, the detection limits are all lower than the drinking water concentrations allowed by the U.S. Environmental Protection Agency. This study also provides a theoretical basis and methodological support for the subsequent application of PQDs in the detection of water pollutants.
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Frontiers in Microbiology
·
2024
·
IF 4
Wang Liping,Liang Aihua,Huang Jukai
Introduction: Diabetic nephropathy (DN) presents a significant therapeutic challenge, compounded by complex pathophysiological mechanisms. Recent studies suggest Exendin-4 (Ex-4) as a potential ameliorative agent for DN, albeit with unclear mechanisms. This research investigates the effects and underlying mechanisms of Ex-4-enriched exosomes derived from human umbilical cord mesenchymal stem cells (hUCMSCs) on DN, focusing on their renoprotective properties and interactions with gut microbiota.Method: Exosomes from hUCMSCs (hUCMSCs-Exo) were loaded with Ex-4 via electroporation. A streptozotocin (STZ) -induced DN mouse model was employed to assess the therapeutic impact of these engineered exosomes. The study further explored immune cell dynamics, mainly CD4+ regulatory T (Treg) cells, using bioinformatics, flow cytometry, and the influence of gut microbiota through antibiotic treatment and specific bacterial reintroduction.Results: Treatment with hUCMSCs-Exo@Ex-4 significantly improved key DN markers, including blood glucose and proteinuria, alleviating kidney damage. A notable decrease in natural Treg cell infiltration in DN was observed, while Ex-4-loaded exosomes promoted CD4+ Treg cell induction. The therapeutic benefits of hUCMSCs-Exo@Ex-4 were diminished upon CD4+ Treg cell depletion, underscoring their role in this context. Notably, CD4+ Treg cell induction correlated with the presence of Prevotella species, and disruption of gut microbiota adversely affected these cells and the therapeutic efficacy of the treatment. However, the reintroduction of Prevotella strains counteracted these adverse effects.Discussion: This study elucidates a novel therapeutic mechanism of Ex-4-loaded hUCMSCs exosomes in DN, highlighting the induction of CD4+ Treg cells mediated by specific gut microbiota components. These findings underscore the potential of leveraging gut microbiota and immune cell interplay in developing effective DN treatments.
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