RSC Advances
·
2014
·Vol. 4
·期 98
·55139-55149
·
IF 3.708
Jinlong Yang,Chunmei Gao,Shaoyu Lü,Xinggang Wang,Mingjia Chen,Mingzhu Liu
A novel amphiphilic polymer (mPEGylated starch-deoxycholic acid, mPEG-St-DCA) was successfully prepared by grafting hydrophobic deoxycholic acid (DCA) into mPEGylated starch. According to the characterization of 1H NMR and FTIR, mPEG-St-DCA polymers could self-assemble into micelles with spherical core–shell structures. With the degree of substitution (DS) of DCA increasing, the average size of micelles (pH 7.4) decreased to below 200 nm. Correspondingly, the critical micelle concentration (CMC) decreased from 0.048 to 0.022 mg mL−1. And zeta potential values were near −2 mV. But under the condition of pH 6.5, the size and CMC showed an increasing trend. Doxorubicin (DOX), a model anticancer drug, was efficiently loaded into mPEG-St-DCA micelles, and in vitro release exhibited that DOX-loaded micelles had a good in vitro pH-induced drug release. MTT assays confirmed that mPEG-St-DCA micelles were biocompatible with HeLa cells, and DOX-loaded micelles had a relatively better cytotoxicity against HeLa cells with a remarkably high IC50 of 5.74 μg mL−1. Confocal laser scanning microscopy (CLSM) analyses demonstrated that mPEG-St-DCA micelles could be internalized efficiently by HeLa cells to realize intracellular DOX release, which further enhanced the inhibition of cell proliferation. On the basis of the above results, it was indicated that novel amphiphilic mPEG-St-DCA micelles with pH-response could be used as drug delivery carriers for cancer therapy.
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NANOTECHNOLOGY
·
2013
·Vol. 24
·期 36
·365101
·
IF 3.842
Fangkai Du,Yunhao Ming,Fang Zeng,Changmin Yu,Shuizhu Wu
Intracellular pH plays a critical role in the function of cells, and its regulation is essential for most cellular processes. In this study, we demonstrate a fluorescence resonance energy transfer (FRET)-based ratiometric pH nanosensor with carbon-dot (CD) as the carrier. The sensor was prepared by covalently linking a pH-sensitive fluorescent dye (fluorescein isothiocyanate, FITC) onto carbon-dot. As the FRET donor, the carbon-dot exhibits bright fluorescence emission as well as λex-dependent photoluminescence emission, and a suitable excitation wavelength for the donor (CD) can be chosen to match the energy acceptor (fluorescein moiety). The fluorescein moieties on a CD undergo structural and spectral conversion as the pH changes, affording the nanoplatform a FRET-based pH sensor. The CD-based system exhibits a significant change in fluorescence intensity ratio between pH 4 and 8 with a pKa value of 5.69. It also displays excellent water dispersibility, good spectral reversibility, satisfactory cell permeability and low cytotoxicity. Following the living cell uptake, this nanoplatform with dual-chromatic emissions can facilitate real-time visualization of the pH evolution involved in the endocytic pathway of the nanosensor. This reversible and low cytotoxic fluorescent nanoplatform may be highly valuable in a variety of biological studies, such as endocytic trafficking, endosome/lysosome maturation, and pH regulation in subcellular organelles.
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APPLIED SURFACE SCIENCE
·
2015
·
IF 2.711
Congli Wang,Lizhen Huang,Shengmei Song,Bassam Saif,Yehong Zhou,Chuan Dong,Shaomin Shuang
The β-cyclodextrin assemblied magnetic Fe 3 O 4 nanoparticles (β-CD-MNPs) were successfully fabricated via a layer-by-layer method. Possessing an average size 14 nm, good stability and super-paramagnetic response (Ms 64 emu/g), the resultant nanocomposites could be served as a versatile biocompatible platform for selective loading, targeted delivery and pH-responsive release of stereoisomeric doxorubicin (DOX) and epirubicin (EPI). 1 H-nuclear magnetic resonance ( 1 H NMR) and the computer simulation further give the evidence that partial anthracene ring of drug molecule is included by β-CD. In addition, non-toxic β-CD-MNPs have excellent biocompatibility on MCF-7 cells, and cellular uptake indicate that different amounts of DOX or EPI can be transported to targeting site and released from the internalized carriers. The results demonstrate that as-prepared β-CD-MNPs could be a very promising vehicle for DOX and EPI.
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TALANTA
·
2015
·
IF 3.545
Fei Qu,Xuan Zou,Rongmei Kong,Jinmao You
In this assay, a tunable pH sensing system was developed based on Ag nanoclusters (Ag NCs) capped by hyperbranched polyethyleneimine (PEI) with different molecular weights (abbreviated as Ag NC-PEIs). For instance, when the molecular weight of PEI was 600 or 1800, the fluorescence intensities of Ag NCs exhibited a linear fashion over the pH range 4.10–7.96; when the molecular weight of PEI was 25,000, the pH linear range was from 4.78 to 7.96; when the molecular weight of PEI was 70,000, the pH linear range was 6.09–8.95. According to the molecular weight of PEI 600/1800, 25,000, and 70,000, the color change point was pH 4.10–4.78, 5.33–6.09, and 6.09–6.80, respectively. Therefore, Ag NC-PEI 600 and 1800 were proper to acid conditions; Ag NC-PEI 25,000 was sensitive to weak acid media; while Ag NC-PEI 70,000 was adapted to neutral solution. The tunable and selective color change points brought an excellent feature of Ag NC-PEIs as visual pH indicators, which was flexible and applicable to a variety of environments. Besides, the ratios of absorbance at 415 nm and 268 nm of Ag NCs also showed linear relationships with pH variations. Therefore, there were three ways of this system for sensing pH values, including fluorescence assay, ultraviolet–visible measurement, and visual detection, suggesting that this tunable pH-sensing platform was more feasible, reliable, and accurate.
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ACS Applied Materials & Interfaces
·
2015
·
IF 6.723
Liyi Fu,Chunyang Sun,Lifeng Yan
Theranostic polymeric nanomaterials are of special important in cancer treatment. Here, novel galactose targeted pH-responsive amphiphilic multiblock copolymer conjugated with both drug and near-infrared fluorescence (NIR) probe has been designed and prepared by a four-steps process: (1) ring-opening polymerization (ROP) of N-carboxy anhydride (NCA) monomers using propargylamine as initiator; (2) reversible addition–fragmentation chain transfer (RAFT) polymerization of oligo(ethylene glycol) methacrylate (OEGMA) and gal monomer by an azido modified RAFT agent; (3) combing the obtained two polymeric segments by click reaction; (4) NIR copolymer prodrug was synthesized by chemical linkage of both cyanine dye and anticancer drug doxorubicin to the block copolymer via amide bond and hydrazone, respectively. The obtained NIRF copolymers were characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and its was measured by means of micelles dynamic light scattering (DLS), field emission transmission electron microscopy (FETEM), and UV–vis and fluorescence spectrophotometry. The prodrug has strong fluorescence in the near-infrared region, and a pH sensitive drug release was confirmed at pH of 5.4 via an in vitro drug release experiment. Confocal laser scanning microscopy (CLSM) and flow cytometry experiments of the prodrug on both HepG2 and NIH3T3 cells reveal that the galactose targeted polymeric prodrug shows a fast and enhanced endocytosis due to the specific interaction for HepG2 cells, indicating the as-prepared polymer is a candidate for theranosis of liver cancer.
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MATERIALS CHEMISTRY AND PHYSICS
·
2014
·
IF 2.129
Liang Cui,Rui Wang,Xuqiang Ji,Ming Hu,Bin Wang,Jingquan Liu
The preparation of pH responsive, biodegradable, biocompatible and cross-linked polymer capsules for controlled drug release is presented. These capsules were prepared using silica particles as templates for surface grafting of poly (acrylic acid) (PAA) and PAA-co-poly(polyethylene glycol) acrylate) (PAA-PPEGA) block copolymer via reversible addition fragmentation chain transfer (RAFT) polymerization directly from silica particles, followed by cross-linking with cystamine dihydrochloride and removal of the silica template in the presence of hydrofluoric acid, respectively. The resultant polymer capsules were water soluble, biocompatible with a mean diameter of approximately 260 ± 10 nm, and non-toxic to human cells at low concentration, which are favorable to be utilized as drug carriers for pH responsive and biodegradation controlled drug release. Doxorubicin hydrochloride (DOX) was chosen as a model drug to test the drug loading and releasing properties of the polymer capsules. It was found that the DOX could be effectively loaded into the PAA and PAA-PPEGA capsules with a loading capacity up to 52.24% and 36.74%, respectively. The pH and biodegradation controlled release behaviors of DOX loaded PAA-PPEGA capsules were also explored. The results imply that both PAA and PAA-PPEGA capsules are promising platforms for pH and biodegradation controlled drug delivery systems, while the PAA-PPEGA capsules exhibit less cytotoxicity.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2017
·Vol. 24
·期 21
·17598-17605
·
IF 2.741
Wang Na,Jia Daqing,Jin Yaoyao,Sun Sheng-Peng,Ke Qiang
The present study investigated the degradation of trichloroethylene (TCE) in sand suspensions by Fenton-like reaction with magnetite (Fe 3 O 4 ) in the presence of various chelators at circumneutral pH. The results showed that ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) greatly improved the rate of TCE degradation, while [S,S]-ethylenediaminedisuccinic acid (s,s-EDDS), malonate, citrate, and phytic acid (IP6) have minimal effects on TCE degradation. Quenching tests suggested that TCE was mainly degraded by hydroxyl radical (HO · ) attack, with about 90% inhibition on TCE degradation by the addition of HO · scavenger 2-propanol. The presence of 0.1–0.5% Fe 3 O 4 /sand ( w / w ) contributed to 40% increase in TCE degradation rates. In particular, the use of chelators can avoid high concentrations of H 2 O 2 required for the Fenton-like reaction with Fe 3 O 4 , and moreover improve the stoichiometric efficiencies of TCE degradation to H 2 O 2 consumption. The suitable concentrations of chelators (EDTA and NTA) and H 2 O 2 were suggested to be 0.5 and 20 mM, respectively. Under the given conditions, degradation rate constants of TCE were obtained at 0.360 h −1 with EDTA and 0.526 h −1 with NTA, respectively. Enhanced degradation of TCE and decreased usage of H 2 O 2 in this investigation suggested that Fenton-like reaction of Fe 3 O 4 together with NTA (or EDTA) may be a promising process for remediation of TCE-contaminated groundwater.
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RSC Advances
·
2017
·Vol. 7
·期 42
·25978-25986
·
IF 3.108
Ce Cheng,Shengfeng Peng,Ziling Li,Liqiang Zou,Wei Liu,Chengmei Liu
The poor water solubility and bioavailability of curcumin can be improved by encapsulating it into liposomes. However, the existing encapsulation technologies, such as the thin film method and the ethanol injection method, are complex and require the use of organic solvents. In this study, an organic solvent-free and easily scalable encapsulation technique was studied by utilizing the pH-dependent solubility properties of curcumin. Phospholipid was dissolved in water to form liposomes. Curcumin was deprotonated and dissolved under alkaline conditions and then encapsulated into the liposomes after acidification. Morphological observation and X-ray diffraction analysis confirmed that curcumin liposomes had been successfully prepared. Curcumin liposomes prepared by the pH-driven method were stable during storage. During in vitro digestion, curcumin liposomes prepared by the pH-driven method showed similar bioaccessibility to those prepared by the thin film method and higher bioaccessibility than those prepared by the ethanol injection method. The pH-driven method, which is organic solvent-free and easily scalable for industrial production, is thus a promising method for the preparation of curcumin liposomes.
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COLLOID AND POLYMER SCIENCE
·
2015
·Vol. 293
·期 10
·2979-2984
·
IF 1.865
Su Rong,Wang Qianming
The design and synthesis of cross-linked siloxane and polymeric matrices incorporated with terbium or europium complexes have been studied. The preparation of hybrid hosts demonstrated that poly(vinyl alcohol) in the presence of tetraethoxysilane with various concentrations gave different mechanical stabilities and water solubilities. The as-derived films exhibited excellent photophysical properties of lanthanides with large Stokes shifts, narrow emissions, and high color purity. It has been found that the luminescent materials were dramatically quenched over the assayed pH ranges (pH 7 to 1 and pH 7 to 14). These optical probes could be recycled for ten times by changing the aqueous media. The novel inorganic-organic responsive films that can be switched on or off based on pH values will find potential application in biological analysis.
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Materials Science & Engineering C-Materials for Biological Applications
·
2015
·
IF 3.088
Luyan Wu,Liping Zhang,Gang Shi,Caihua Ni
Zwitterionic nanoparticles have excellent serum stability. In this study, pH/redox responsive polymer was synthesized through a modification of dextran using succinic acid, followed by crosslinking with cystamine. The polymer could self-assemble into stable nanoparticles (NPs) in aqueous solution. The NPs carried certain amount of free carboxyl and amino groups on the surface, which endowed the NPs excellent anti-protein adsorption ability. The surface charge was negative at pH 7.4 and was converted to positive at pH 5.0. It was revealed that the NPs showed little non-specific protein adsorption and had excellent serum stability, and the NPs could be internalized in Hela cells rapidly. This result was ascribed to the charge reversible feature of the NPs. Doxorubicin (DOX) was loaded in the NPs for release studies in vitro. The DOX-loaded NPs exhibited obvious pH and reduction sensitivities in response to the environment in tumor cells due to the introduction of carboxyl groups, amino groups and disulfide bonds in the NPs. The NPs were biocompatible, biodegradable, and could be potentially applied as anticancer drug carriers for enhancement of tumor intercellular uptake of doxorubicin.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Guli Li,Bei Zhang,Xinbo Song,Ying Xia,Haibo Yu,Xinfu Zhang,Yi Xiao,Youtao Song
Mitochondrial pH plays a pivotal role in the regulation of physiological process. Developing ratiometric fluorescent probes for real-time detection of mitochondrial pH fluctuation is still highly demanded yet challenging. Herein, we present a novel strategy to design a ratiometric probe (FDI) by broadening absorption spectrum (360–700 nm) of fluorescein fluorophore. Unsaturated dialkene/indole quaternary ammonium moiety has broadened absorption and emission spectrum of fluorescein fluorophore to provide ratiometric detection by CLSM in dual excitation/dual emission mode, as well as directionally accumulated in mitochondria in living cells. Superior to commercially mitochondrial tracker, Carboxy-SNARF, probe FDI exhibits excellent and fast cell-membrane permeability and mitochondrial-targetability. It has been demonstrated that FDI could permit real-time monitoring of pH alkalization of mitochondria stimulated by chloroquine. Owing to nondestructive process and reversible ratiometric response to pH, image acquisition can be repeated frequently to trace and monitor the time course of mitochondrial pH responses. It is clearly confirmed that FDI would be a promising probe for real-time tracking of mitochondrial pH changes in the biomedical and biological fields.
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RSC Advances
·
2017
·Vol. 7
·期 24
·14888-14901
·
IF 3.108
Shifeng Yan,Yuanyuan Sun,An Chen,Lei Liu,Kunxi Zhang,Guifei Li,Yourong Duan,Jingbo Yin
A novel class of pH-responsive hollow poly(L-glutamic acid)/chitosan (PLGA/CS) nanogels was fabricated by a templating approach, which was mild and surfactant free, and combined with a “grafting from” method and intermacromolecular crosslinking technique. The surface grafting, crosslinking reaction, nanogel fabrication and microstructure were investigated by FTIR, 1H NMR, XRD, TGA, light scattering, and electron microscopy. The size of the resultant PLGA/CS nanogels could be accurately controlled by simply changing the size of the silica template. The nanogels responded to changes in environmental pH, elucidated according to the variation of the size of the nanogels and zeta potential at different pH values. Taking water-soluble antineoplastic agent mitoxantrone (MTX) as a model drug, the nanogels presented high loading ability at high-pH environment and rapid MTX release behavior under acidic conditions. MTT assays used to study the in vitro cytotoxicity of PLGA/CS nanogels showed a negligible cytotoxicity in mouse fibroblast L929 cells. Compared with bare MTX, MTX loaded PLGA/CS nanogels exhibited an enhanced inhibition effect to human gastric carcinoma SGC7901 cells. Fluorescence microscopy and flow cytometry analysis results demonstrated efficient cellular uptake of the PLGA/CS nanogels into the cells. These studies suggest that such pH-responsive PLGA/CS hollow nanogels might have great potential in controlled drug delivery systems.
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