Nanoscale
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2018
·Vol. 10
·期 26
·12788-12796
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IF 7.233
Shuang E,Quan-Xing Mao,Xiao-Li Yuan,Xiao-Lei Kong,Xu-Wei Chen,Jian-Hua Wang
Organelles play crucial roles in cellular activities and the functions of organelles are related greatly to the pH values, therefore, the bio-imaging of targeted organelles and their related pH sensing is of great importance in biological assays. Herein we report the fluorescence imaging of specific organelles, i.e., lysosomes and endoplasmic reticulum, and their pH sensing with surface regulated carbon dots (CDs). Carbon dots functionalized with amine groups (ACDs) are first prepared by hydrothermal treatment of citric acid and urea, and then laurylamine functionalized CDs (LCDs) are obtained via the conjugation of laurylamine with ACDs. The as-prepared ACDs and LCDs provide clear and bright imaging results for the lysosome and endoplasmic reticulum, respectively. The subcellular targeting features of the two CDs are attributed to their surface chemistries and cellular uptake pathways. Moreover, both the CDs are pH responsive within a certain pH range, i.e., 4.0–5.4 for ACDs and 6.2–7.2 for LCDs. The ACDs and LCDs are thus successfully applied to visualize the pH fluctuations of the lysosome and endoplasmic reticulum in MCF-7 cells.
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Materials Chemistry Frontiers
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2018
·Vol. 2
·期 8
·1529-1538
·
IF 0
Lijing Niu,Feiyan Zhu,Bowen Li,Lingling Zhao,Hongze Liang,Yinghua Yan,Hui Tan
A folate-conjugated and pH-sensitive polymeric micellar system for the co-delivery of DOX and PTX was studied. A doxorubicin conjugated prodrug was synthesized via Schiff's base reaction. Subsequently, folate was grafted onto the prodrug and PTX was encapsulated. Sustained drug release of both DOX and PTX from the polymeric micelles was observed and the release rate could be accelerated by decreasing the media pH. A cellular uptake assay revealed that the polymeric micelles were internalized in the cytoplasm via endocytosis by SW1353 cells, and the cellular uptake was enhanced for the folate-conjugated micelles due to an active FR-mediated endocytosis pathway, showing stronger red fluorescence compared to that of non-folate micelles. The in vitro anticancer efficiency of the polymeric micellar system was evaluated using a cytotoxicity assay by incubating different drug formulations with the SW1353 cells. Both free drugs and micellar formulations displayed inhibition of cell growth at different levels, while the folate-conjugated dual-drug loaded polymeric micelles (Folate–Oxd–DOX/PTX) displayed a much lower IC50 value than other drug formulations, indicating a desirable in vitro anticancer efficiency due to the synergistic effect of co-delivery and active targeting. Thus, the polymeric micellar system is a promising platform for targeted cancer chemotherapy.
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SENSORS AND ACTUATORS B-CHEMICAL
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2018
·
IF 5.667
Xin Hai,Yiting Wang,Xiaoyao Hao,Xuwei Chen,Jianhua Wang
Folic acid (FA) encapsulated graphene quantum dots (FA-GQDs) were prepared via a one-pot microwaved alkali cutting method, using graphene oxide (GO) and FA as raw material. TEM and AFM images revealed that FA was successfully cross-linked on the surface of GQDs under alkali circumstance, giving rising to stable and homogeneous FA-GQDs with size of about 33.6 nm. XPS and FT-IR confirmed that there are abundant hydroxyl, carboxyl and amino groups on the encapsulated FA-GQDs. The as-prepared FA-GQDs possessed the fluorescence behaviors of multi-excitation and emission sites, and exhibited sensitive response to the pH variation within the pH range of 3–9, making it excellent fluorescence probe for pH sensing in cell lysate and environmental water samples. The broad emission with pH-sensitive characteristic and low toxicity of FA-GQDs also provided an alternative for the specific multicolor imaging and sensing of pH in living cells.
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TALANTA
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2018
·
IF 4.244
Shenghong Yang,Xiao Chen,Shuqin Liu,Fuxin Wang,Gangfeng Ouyang
Fluorescent carbon nanoparticles (FCNPs) have been deeply researched and widely applied in recent years due to their good optics performance, chemical stability and biocompatibility. Herein, a green and rapid microwave-assisted solid-phase synthesis (solvent-free) approach was proposed for the fabrication of highly FCNPs in a very short period of time, 4 min. The as-prepared FCNPs can emit a blue emission with quantum yield of up to 63.2% in water solution and show yellow fluorescence in the solid state. The FCNPs also exhibit special solvent effect that the fluorescence emission can be adjusted by controlling the solvent ratio of ethanol and water. Most importantly, the FCNPs possess a narrow-range pH response. The probe responds linearly and rapidly to minor pH fluctuations within the range of 3.47–5.10 and the correlation coefficient is above 0.99. The proposed FCNPs also exhibit high photostability and reusability. As expected, the cell imaging and intracellular pH monitoring was achieved successfully in living SMMC 7721 hepatoma cells by this probe. The FCNPs is promising as a convenient and general fluorescent pH sensor for bioimaging applications.
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JOURNAL OF HAZARDOUS MATERIALS
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2018
·
IF 6.434
Feng Li,Wei Wang,Chengcheng Li,Runliang Zhu,Fei Ge,Yang Zheng,Yixin Tang
Biomineralization is an interesting naturally occurring process of forming minerals by microorganisms, which offers an efficient way to sequester heavy metal ions within relatively stable solid phases. In this study, Bacillus cereus Cd01 was selected to investigate effects of self-mediated pH on biosorption and biomineralization of Cd 2+ in whole 72h cultivation period. Results revealed that strain Cd01-mediated pH decrease of the cultivation medium from 7.0 to 6.1 inhibited biosorption of Cd 2+ on Cd01 cells at the initial cultivation period, while an increased pH from 6.1 to 7.4 facilitated biosorption of Cd 2+ on Cd01 cells at the middle and late cultivation period. The reasons were mainly that self-mediated pH altered cell surface hydrophobicity and cell membrane fluidity of strain Cd01. Moreover, biosorption and bioaccumulation of Cd 2+ on Cd01 cells in the period of increased pH promoted biomineralization of Cd 2+ observed by the transmission and scanning electron microscopes. The analyses of energy dispersive spectroscopy, X-ray photoelectron spectroscopy and select area electron diffraction demonstrated that Cd 2+ loaded on Cd01 cells was biomineralized into polycrystalline and/ or amorphous cadmium sulfide and cadmium phosphate. These results suggest that strain Cd01 may play a potential role in biomineralization remediation of heavy metal contaminated soils.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2018
·
IF 3.997
Shujuan Xiong,Zhe Wang,Juan Liu,Xiangping Deng,Runde Xiong,Xuan Cao,Zhizhong Xie,Xiaoyong Lei,Yanming Chen,Guotao Tang
This work has presented a novel strategy for designing pH-sensitive TOS-H-DOX prodrug-loaded TPGS nanomicelles for co-delivery TOS and DOX to enhance tumor therapy and reduce the toxic side effects. DOX was covalently conjugated to the vitamin E succinate through hydrazone bond to produce an pH-sensitive prodrug TOS-H-DOX (amido bond as a control, TOS-A-DOX), which was responsive to the acidic environment in tumor cells, and the prodrugs were subsequently encapsulated in the core of TPGS nanomicelles via hydrophobic effects with a significant drug loading capacity. The pH-sensitive prodrug nanomicelles TOS-H-DOX/TPGS exhibited potent release of DOX in acidic media relative to the pH-insensitive prodrug nanomicelles TOS-A-DOX/TPGS, and further studies of their intracellular uptake and intracellular localization demonstrated that TOS-H-DOX/TPGS nanomicelles can be effectively taken up by cells and drugs can be released. In vitro results confirmed that TOS-H-DOX/TPGS nanomicelles exhibited significant antitumor cell proliferation activity compared to TOS-A-DOX/TPGS and free DOX, TPGS. Furthermore, in vivo studies further confirmed an excellent synergistic antitumor efficacy in MCF-7 tumor-bearing nude mice model. More importantly, the H&E staining of the heart, liver, kidney tissue sections of experimental nude mice showed that TOS-H-DOX/TPGS nanomicelles can reduce damage to them.
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Polymer Chemistry
·
2018
·Vol. 9
·期 22
·3080-3087
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IF 4.927
ChangAn Yang,Ling Chen,He Huang,Tuo Ji,YingXiang Jiang,Xiaobo Chen,CongShan Zhou
Novel tri-stimulus responsive supramolecular dendronized copolymers are prepared through the self-assembly of imine bonds, exhibiting fast and fully reversible phase transitions and trans–cis isomerization in alkaline solutions. The lower critical solution temperature (LCST) is controlled with the aldehyde-to-amino molar ratio, and mostly decreases after UV irradiation. As the pH increases, the LCST has an inflection point caused by two different self-assembly behaviors. The aldehyde and amino monomers are assembled by H-bonds in acids, but by dynamic imine bonds in bases. The copolymer concentration plays an essential role in affecting the LCST. The LCST increases with the aldehyde content when the concentration is 5.0 mg mL−1 and has an inflection point with the aldehyde content when the concentration is 1.0 mg mL−1. The tri-stimuli-responsive copolymers have three advantages: (1) feasible control via pH-adjusting aldehyde–amino bonds, (2) controllable synthesis, and (3) narrow, tunable phase transition temperature by pH, light and the molar ratio.
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RSC Advances
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2018
·Vol. 8
·期 66
·38091-38099
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IF 2.936
Xin Guo,Yufu Zhu,Lei Zhou,Linna Zhang,Yucai You,Hongliang Zhang,Jiajia Hao
As the new representative in the carbonaceous family, carbon dots (CDs) have gained remarkable research interests over the past decade. Herein, we report the facile preparation and thorough performance comparison of three types of carbon dots with the adoption of ubiquitous natural fruit juice as precursors and demonstrate their application in pH sensing, patterning and bioimaging. All the yielded CDs show interesting optical properties including evident single- or two-photon absorption and excitation-dependent photoluminescence along with the high fluorescent yield. A detailed study on the physical properties by EPR and Stokes shift analysis and structural composition analysis by XPS and Raman spectroscopy suggest that the fluorescence of CDs originates from the electron–hole recombination via the defect state. In addition, through the regulation of non-radiative recombination rate of CDs, all the obtained CDs could be applied as fluorescent sensing platforms toward the sensitive detection of the solution pH changes by the indication of CDs' fluorescent yield and lifetime variation. Moreover, it was also proven that the resulting CDs could be employed as fluorescent inks for printing patterns in anti-counterfeit applications and as fluorescent probes for bioimaging of osteoblasts.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
·
IF 11.698
Zhenying Jiang,Lingzhi Wang,Juying Lei,Yongdi Liu,Jinlong Zhang
The application of photo-Fenton process is restricted by the acidic pH and additional hydrogen peroxide (H 2 O 2 ). In order to overcome these drawbacks, a photo-Fenton system of CdS/rGO/Fe 2+ which can perform at natural pH with in situ -generated H 2 O 2 has been successfully developed. Highly efficient photo-Fenton degradation of phenol was achieved under the visible light irradiation via the CdS/rGO/Fe 2+ system. Experimental results showed that phenol could be degraded completely in 1 h at natural pH. The plentiful in situ generation of H 2 O 2 was further proved to act as an important role in phenol degradation with the addition of Fe 2+ . The advantages of degradation at natural pH with in situ -generated H 2 O 2 can provide a new prospective to the environmental-friendly Fenton process.
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CELLULOSE
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2018
·Vol. 26
·期 3
·1825-1839
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IF 3.809
Lin Fengcai,Lu Xiangchao,Wang Zi,Lu Qilin,Lin Guanfeng,Huang Biao,Lu Beili
Cellulose hydrogels usually have poor mechanical properties which seriously limit their applications in biomedical or industrial fields. Herein, an interpenetrating polymer network strategy was proposed to construct double network hydrogels composed of cellulose and polyacrylamide with high mechanical strength and pH responsive properties. The synergistic interactions and strong hydrogen bonds between two networks contributed to the dissipation of mechanical energy, as evidenced by the compressive stress–strain and rheology analyses. The compressive strength and compressive modulus for cellulose–polyacrylamide interpenetrating network (C–PAM IPN) hydrogels could reach up to 5.62 and 22.47 MPa, which is nearly 18 and 23 times higher than that of cellulose hydrogels. Moreover, these tough C–PAM IPN hydrogels exhibit pH sensitive properties in various pH solutions. Therefore, this paper provides a general strategy to enhance the mechanical and physical properties of cellulose-based hydrogels, which are potentially useful in developing novel cellulose-based hydrogels and expanding their applications.
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CARBOHYDRATE POLYMERS
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2018
·
IF 5.158
Meixiao Cheng,Hui He,Hongxiang Zhu,Wei Guo,Wenbo Chen,Fei Xue,Shile Zhou,Xingjuan Chen,Shuangfei Wang
Two novel pH-responsive reversible-wettability biomass cellulose-based materials of cellulose -g- PAA and cellulose -g- PAM were conveniently prepared by grafting acrylic acid (AA) and acrylamide (AM), respectively, onto eucalyptus pulp cellulose. The hydrophobic–oleophilic of cellulose -g- PAA and the oleophobic–hydrophilic of cellulose -g- PAM were converted to oleophobic–hydrophilic and hydrophobic–oleophilic, respectively, as the pH converted from 1 to 9. The pH-responsive mechanism of these cellulose-based materials was investigated by 13 C nuclear magnetic resonance, X-ray photoelectron spectroscopy, and atomic force microscopy analyses. The resulting cellulose -g- PAA and cellulose -g- PAM papers were applied in the switchable separation of oil/water mixtures. Water passed through the cellulose -g- PAA paper at pH = 9 and cellulose -g- PAM paper at pH = 1, while oil was retained. After changing the pH value, oil permeated these papers, but water did not. The papers exhibited excellent regeneration performances; the oil adsorbed on the papers was completely desorbed via pH control.
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Nutrients
·
2018
·Vol. 10
·期 10
·1366
·
IF 4.196
Jie Gao,Xin He,Yuejiao Ma,Xuezhi Zhao,Xiaotao Hou,Erwei Hao,Jiagang Deng,Gang Bai
Chlorogenic acid (CGA), a bioactive component in the human diet, is reported to exert beneficial effects on the regulation of glucose metabolism. This study was designed to investigate the specific target of CGA, and explore its underlying mechanisms. Beneficial effects of CGA in glucose metabolism were confirmed in insulin-treated human hepatocarcinoma HepG2 cells. Protein fishing, via CGA-modified functionalized magnetic microspheres, demonstrated the binding of CGA with protein kinase B (AKT). Immunofluorescence using a CGA molecular probe further demonstrated the co-localization of CGA with AKT. A competitive combination test and hampering of AKT membrane translocation showed that CGA might bind to the pleckstrin homology (PH) domain of AKT. The specific binding did not lead to the membrane translocation to phosphatidylinositol (3,4,5)-trisphosphate (PIP3), but directly activated the phosphorylation of AKT on Ser-473, induced the phosphorylation of the downstream molecules, glycogen synthase kinase 3β (GSK3β) and forkhead box O1 (FOXO1), and improved glucose metabolism. Collectively, our data demonstrate that CGA exerts regulatory effects on glucose metabolism via direct targeting the PH domain of AKT. This study clarifies the mechanism of the potential benefits of nutrients containing CGA in the complementary therapy of glucose metabolism disorders.Keywords:chlorogenic acid;glucose metabolism;protein kinase B (AKT);pleckstrin homology (PH) domain;glycogen synthase kinase 3β (GSK3β);forkhead box O1 (FOXO1)
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