CLEAN-Soil Air Water
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2015
·Vol. 44
·期 1
·72-77
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IF 1.945
Qun He,Ruijuan Qu,Xinghao Wang,Zhongbo Wei,Ping Sun,Zunyao Wang
Although it has been widely known that arsenic poses great threat to organisms and arsenic species account for the toxic effect of the metalloid, relatively little attention has been given to the arsenic toxicity to different organisms at different pH values. Three kinds of aquatic organisms including Photobacterium phosphoreum , Daphnia magna , and Danio rerio were used to study the effects of pH on the toxicity of arsenic. Toxicity test results were analyzed by calculating EC 50 values and for arsenic species at five different pH values (5.0, 6.0, 7.0, 8.0, and 9.0). As a result, As(III) is more toxic to the tested organisms than As(V), and P. phosphoreum was more sensitive to the toxicity of arsenic than D. magna and D. rerio . The toxicity of As(III) species is different for different organisms: dihydrogen arsenite, H 2 AsO 3 – , is more toxic to P. phosphoreum and D. rerio than arsenous acid, H 3 AsO 3 , while H 3 AsO 3 is more toxic to D. magna . As for As(V), arsenate, HAsO 4 2− , is the most toxic to P. phosphoreum , whereas dihydrogen arsenate, H 2 AsO 4 – , may be responsible for the toxicity to D. magna and D. rerio . As(III) and As(V) are more toxic to P. phosphoreum in an alkaline environment, while for D. magna in an acidic environment and As(III) is more toxic to D. rerio in an alkaline environment and As(V) in an acidic environment.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2014
·
IF 3.107
Nannan Chen,Lianzhu Lin,Weizheng Sun,Mouming Zhao
In this study, we examined the possibility of preparing stable soy protein nanogels by simply heating homogeneous soy protein dispersion. The protein nanogels formed were characterized by z-average hydrodynamic diameter, polydispersity index, turbidity, ζ-potential, morphology, and their stability to pH and ionic strength change. Soy protein dispersion (1% w/v) was homogeneous around pH 5.9 where it had the lowest polydispersity index (∼0.1). Stable and spherical nanogels were formed by heating soy protein dispersion at pH 5.9 under 95 °C. They sustained constantly low polydispersity index (∼0.1) in the investigated pH range of 6.06–7.0 and 2.6–3.0. The nanogels were pH-sensitive and would swell with pH change. They were stable at 0–200 mM NaCl concentration. Denaturation of soy glycinin was the prerequisite for the formation of stable nanogels. Soy protein nanogels had a core–shell structure with basic polypeptides and β subunits interacting together as the hydrophobic core; and acid polypeptides, α′, and α subunits locating outside the core as hydrophilic shell. The inner structure of soy protein nanogels was mainly stabilized by disulfide bonds cross-linked network and hydrophobic interaction. Soy protein nanogels made in this study would be useful as functional ingredients in biotechnological, pharmaceutical, and food industries.
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Journal of Materials Chemistry B
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2015
·Vol. 3
·期 37
·7401-7407
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IF 4.726
Haibo Wang,Gongyan Liu,Shihua Dong,Junjie Xiong,Zongliang Du,Xu Cheng
To construct a smart drug delivery system for simultaneous cellular imaging and cancer therapy, a pH-responsive amphiphilic polymer (MPEG-hyd-TPE) with aggregation-induced emission (AIE) character was designed and successfully synthesized. Polymeric micelles self-assembled from MPEG-hyd-TPE exhibited a significant AIE effect in an aqueous solution with excellent biocompatibility; thus, it can be used for potential bioimaging applications. Moreover, the drug-loaded micelles showed typical pH-regulated drug release behavior. DOX was released more rapidly after the drug-loaded micelles were internalized into cancer cells due to the cleavage of the hydrazone bond under acidic endosomal/lysosomal conditions. In addition, in vitro results demonstrated that the drug-loaded micelles exhibited dose-dependent cytotoxicity to HeLa cells.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2015
·
IF 4.152
Hongshan Liang,Bin Zhou,Jing Li,Wei Xu,Shilin Liu,Yan Li,Yijie Chen,Bin Li
A pH-responsive system by constructing a designable coordination bonding-based metal-tannic acid (TA) architecture on zein nanoparticles (NPs) has been investigated. Film formation was initiated by the adsorption of the polyphenol and directed by pH-dependent, multivalent coordination bonding. The prepared metal-TA coated zein NPs (zein-TA/metal NPs) demonstrated good stability to maintain particle size in cell culture medium at 37 °C. The microstructure of the NPs was revealed by transmission electron microscopy (TEM). To confirm the surface chemical information of the NPs, XPS analysis was performed. Furthermore, in vitro viability studies revealed that the zein-TA/metal NPs showed no significant cytotoxicity against HepG2 cells for 24 h. Because of the pH-responsive coordination bonding between TA and metal ions, the functional property of the metal-TA films was tailored for drug delivery. Biocompatible AuNPs were produced using zein-TA/metal NPs as reducing and stabilizing agents which were promising in the photothermal therapy of cancers and other diseases.
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ACS Biomaterials Science & Engineering
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2015
·
IF 0
Qiu Li,Yiguang Jin,Miao Li,Jun-Xing Dong
Tumor targeting and controlled drug release at the target are the key problems for cancer pharmacotherapy. A simply structured pH-responsive nanocarrier was prepared to achieve the above aims in this study. A four-armed star copolymer, tetra-(methoxy-poly(ethylene glycol)-poly(2-(N,N-diethylamino)ethyl methacrylate)-poly(ε-caprolactone) pentaerythritol ((mPEG-pDEA-PCL)4-PET, PDCP), was synthesized via the ring-opening polymerization, atom transfer radical polymerization and click chemistry, which formed a monomolecular nanocarrier in water. Its size and zeta potential were strongly pH-dependent from 71 nm and 2.1 mV at pH 8 to 127.5 nm and 25.4 mV at pH 5. The morphological change of pDEA chains was the basic reason. The chains were protonated at lower pH so as to freely extend to the aqueous media, though they were hydrophobic at higher pH to coat on the surface of hydrophobic cores. The star-shaped PDCP had a large hydrophobic core to load hydrophobic drugs (e.g., paclitaxel). High effective drug entrapment in the blood circulation and rapid drug release at the tumor tissues was achieved in PDCP due to its pH-responsive function. The MCF-7 cytotoxicity of the paclitaxel-loaded PDCP nanocarriers at pH 6.5 was similar to free paclitaxel. And the PDCP nanocarriers were well internalized by the MCF-7 cells according to the flow cytometry and laser confocal microscopy. The paclitaxel-loaded PDCP nanocarriers showed the comparable in vivo anticancer effect to the paclitaxel solution (Taxol) although the former’s toxicity was much lower than the latter. The star-shaped pH-responsive monomolecular PDCP nanocarriers are suitable to deliver hydrophobic anticancer drugs for cancer therapy with tumor targeting and controlled drug release.
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JOURNAL OF NANOPARTICLE RESEARCH
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2015
·Vol. 17
·期 2
·1-11
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IF 2.184
Zhang Yan,Lin Xia,Du Xuli,Geng Sicong,Li Hongren,Sun Hong,Tang Xing,Xiao Wei
In this work, we designed and developed a delivery system composed of enteric Eudragit L100-cysteine/reduced glutathione nanoparticles (Eul-cys/GSH NPs) for oral delivery of insulin. First, interactions between Eul-cys and mucin glycoproteins, which are believed to be the result of disulfide bonds, were confirmed using rheology experiments. Subsequently, the insulin-loaded Eul-cys/GSH NPs were prepared by the diffusion method using the rich gel network multipore structure at the surface of the Eul-cys when the pH was higher than the p K a of Eul-cys polymer. The Eul-cys/GSH NPs obtained were characterized by dynamic light scattering, transmission electron microscopy, and atomic force microscopy. The results obtained showed that the average particle size ranged from 240 to 280 nm, and the particles were almost spherical in shape. The in vitro drug release results showed that the Eul-cys/GSH NPs retained a large amount of insulin in simulated gastric fluid, while a significant insulin release was found in simulated intestinal fluid. The in situ release study suggested that NPs released a greater amount of FITC-insulin (49.2 %) into the intestinal mucus layer compared with that of FITC-insulin solution (16.4 %), which facilitating insulin delivery through the intestinal mucosa. Eul-cys/GSH NPs exhibited promising mucoadhesive properties demonstrated using an in vitro cell model. Consequently, NPs were introduced into the ileum loop of healthy rats, thus enhancing the intestinal absorption of insulin and providing a prolonged reduction in blood glucose levels. These results suggest that Eul-cys/GSH NPs may be a promising delivery system for the treatment of diabetes.
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CARBOHYDRATE POLYMERS
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2015
·
IF 4.074
Xie Rui-Hong,Ren Peng-Gang,Hui Jian,Ren Fang,Ren Lian-Zhen,Sun Zhen-Feng
In this study, graphene oxide reinforced regenerated cellulose/polyvinyl alcohol (GO–RCE/PVA) ternary hydrogels were successfully prepared via a repeated freezing and thawing method in NaOH/urea aqueous solution. The effect of GO content on the mechanical properties, swelling behavior, water content of composite hydrogels was investigated. It was found that the mechanical properties of GO–RCE/PVA ternary hydrogels were largely enhanced relative to RCE/PVA hydrogels. With the addition of 1.0 wt% GO, the tensile strength was increased by 40.4% from 0.52 MPa to 0.73 MPa, accompanied by the increase of the elongation at break (from 103% to 238%). Meanwhile, GO–RCE/PVA ternary hydrogels performed the excellent pH-sensitivity, and the higher pH leaded to higher swelling ratio. With 0.8 wt% GO loading, the swelling ratio of GO–RCE/PVA ternary hydrogel was improved from 150% (pH = 2) to 310% (pH = 14). In addition, a slight increase in the water content of the ternary hydrogel was achieved with increasing concentrations of GO. It is believed that this novel ternary hydrogels is a promising material in the application of biomedical engineering and intelligent devices.
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Materials Science & Engineering C-Materials for Biological Applications
·
2015
·
IF 3.088
Shuang Xu,Yan Li,Zhenjie Chen,Cuilan Hou,Tong Chen,Zhigang Xu,Xiaoyu Zhang,Haixia Zhang
Mesoporous silica nanoparticles (MSNs) combining gold particles (MSNs–Au) were synthesized as nanocarriers for glutathione (GSH) and pH dual-sensitive intracellular controlled release of the anti-cancer drug doxorubicin (DOX). The MSNs were used as an adsorbent for DOX, and the ultra-small gold nanospheres (Au NPs) partly operated as gatekeepers to control the release of DOX from the pores of MSNs and as the driver of drug release in the presence of GSH due to the association between GSH and Au particles. Under different pH conditions, DOX release changed due to different levels of dissociation between the –SH group on the MSNs and the Au particles. The composition, morphology, and properties of the as-prepared composites were characterized by elemental analysis, fluorescence spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, nitrogen adsorption–desorption, thermal gravimetric and UV–visible spectroscopy. The in vitro release experiments showed that these smart nanocarriers effectively avoided drug leakage in the neutral media. Cytotoxicity and imaging studies also indicated that DOX-loaded Au-MSNs ( [email protected] –Au) had a significant inhibitory effect on the growth of Tca8113 cells and sustained the release rate of DOX
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RSC Advances
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2015
·Vol. 5
·期 110
·90671-90681
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IF 3.84
Cundian Gao,Junli Ren,Weiqing Kong,Runcang Sun,Qifeng Chen
Temperature/pH dual-responsive hydrogels were prepared by the grafting copolymerization of xylan possessing different functional groups with N-isopropylacrylamide and acrylamide using N,N′-methylenebis-acrylamide as a cross-linker and 2,2-dimethoxy-2-phenylacetophenone as a photoinitiator via ultraviolet irradiation. The influence of xylan and glycidyl methacrylate-modified xylan (GMAX) as the raw materials on the mechanical properties of hydrogels was comparatively investigated. Hydrogels were characterized by SEM, FTIR, TGA and XRD. The prepared hydrogels demonstrated a rapid phase transition temperature around 35 °C. The cumulative release rate of acetylsalicylic acid for xylan-based hydrogels and GMAX-based hydrogels reached to 77.5% and 84.2% in the intestinal fluid, respectively. GMAX-based hydrogels had a drug encapsulation efficiency of 95.21% and low drug release rate in gastric fluid. NIH3T3 cells in GMAX-based hydrogels had the high cell viability by MTT essay. Therefore, GMAX-based hydrogels had the good biocompatibility which make them promising in biomedical applications, especially as intestinal-targeted drug carriers.
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MACROMOLECULAR RAPID COMMUNICATIONS
·
2015
·Vol. 36
·期 6
·533-537
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IF 4.941
Hao Meng,Jing Zheng,Xiufang Wen,Zhiqi Cai,Jiawei Zhang,Tao Chen
A simple strategy is provided to construct a novel pH- and sugar-induced shape memory hydrogel based on dynamic phenylboronic acid (PBA)–diol interactions formed by PBA-modified sodium alginate (Alg-PBA) and poly(vinyl alcohol) (PVA). The dynamic PBA–diol ester bonds serve as temporary cross-links and stabilize the deformed shape of the hydrogel. The disassociation of the PBA–diol ester bonds is explored in acidic conditions and aqueous solutions of glucose and fructose, which endow the hydrogel with shape memory performances.
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2014
·Vol. 52
·期 13
·1771-1780
·
IF 3.245
Yanfeng Chu,Huan Yu,Yingying Ma,Yunti Zhang,Weihai Chen,Guangyan Zhang,Hua Wei,Xianzheng Zhang,Renxi Zhuo,Xulin Jiang
Novel pH and reduction dual-sensitive biodegradable polymeric micelles for efficient intracellular delivery of anticancer drugs were prepared based on a block copolymer of methyloxy-poly(ethylene glycol)- b -poly[(benzyl- l -aspartate)- co -( N -(3-aminopropyl) imidazole- l -aspartamide)] [ m PEG-SS-P(BLA- co -APILA), MPBA] synthesized by a combination of ring-opening polymerization and side-chain reaction. The pH/reduction-responsive behavior of MPBA was observed by both dynamic light scattering and UV–vis experiments. The polymeric micelles and DOX-loaded micelles could be prepared simply by adjusting the pH of the polymer solution without the use of any organic solvents. The drug release study indicated that the DOX-loaded micelles showed retarded drug release in phosphate-buffered saline at pH 7.4 and a rapid release after exposure to weakly acidic or reductive environment. The empty micelles were nontoxic and the DOX-loaded micelles displayed obvious anticancer activity similar to free DOX against HeLa cells. Confocal microscopy observation demonstrated that the DOX-loaded MPBA micelles can be quickly internalized into the cells, and effectively deliver the drugs into nuclei. Thus, the pH and reduction dual-responsive MPBA polymeric micelles are an attractive platform to achieve the fast intracellular release of anticancer drugs. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52 , 1771–1780
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LUMINESCENCE
·
2014
·Vol. 30
·期 1
·98-101
·
IF 1.675
Xuan Liu,Nianyue Wang,Wei Zhao,Hui Jiang
This work reports for the first time a potential-based nano-electrochemiluminescent (ECL) pH sensor, using anatase TiO 2 nanocrystals (NCs) as the ECL probe. The first ECL peak potential of the TiO 2 NCs shifted negatively with increasing pH, showing a linear range from −0.47 V (vs Ag/AgCl) at pH 3 to −1.06 V at pH 10. This phenomenon was attributed to the absorption of ‘potential-determining ions’ of OH − on the surface of TiO 2 NCs, leading to larger impedance of the electron injection. Other common ‘potential-determining ions’, such as phosphate, induced a slight potential shift of 0.03 V at a concentration of 0.1 M. Using urease as an enzyme model, a urea biosensor was developed by the simultaneous modification of urease and TiO 2 NCs on indium–tin oxide (ITO) electrodes. The biosensor, measured on the basis of the pH increase caused by the enzyme catalysis reaction, had a linear range of 0.01–2.0 mM, with a potential shift of 0.175 V. The as-prepared pH sensor, which has simple construction procedures and acceptable sensitivity and selectivity, may provide new avenues for the construction of ECL bioanalytical methodologies. Copyright © 2014 John Wiley & Sons, Ltd.
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