Journal of Materials Chemistry B
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2016
·Vol. 4
·期 14
·2498-2511
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IF 4.872
Zhaojun Jia,Pan Xiong,Yuying Shi,Wenhao Zhou,Yan Cheng,Yufeng Zheng,Tingfei Xi,Shicheng Wei
The design of functional biomaterials that respond intelligently to external stimuli has become a rapidly growing area with widespread interest. This work contributes to the development of a feedback-active anticorrosion system with intriguing self-healing ability to protect magnesium (Mg) from biocorrosion. The system was constituted by an inner micro/nano-porous, ceramic-like pre-coating developed readily from the substrate, and an outermost inhibitor (nanosized cerium (Ce) oxides) containing chitosan (CS) multilayers. Here, the pre-coating acted as both an “anchoring” and a “barrier” layer to acquire structural integrity and improved impedance, respectively. Green CS served as cargo for Ce to be entrapped, harnessing Ce–NH2 complexation chemistry. The coating barrier properties were evaluated by electrochemical impedance spectroscopy. The active corrosion inhibition was assessed by immersion degradation tests with respect to Mg2+ release, pH alteration, crack development, and scanning Kelvin potential. To our delight, the coatings effectively protected the substrate from biocorrosion in vitro compared with bare alloys. Putatively, the pH-triggered formation of Ce oxide precipitation, along with the pH-buffering activity and movable swelling capacity of CS macromolecules, should have contributed to restraining the anodic activity and healing the cracks/defects dynamically. Furthermore, the coated substrate had the biocompatibility to elicit better attachment and growth of osteoblasts.
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ACS Sustainable Chemistry & Engineering
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2016
·
IF 5.267
Beili Lu,Fengcai Lin,Xin Jiang,Jiajia Cheng,Qilin Lu,Jianbin Song,Chong Chen,Biao Huang
A facile, environmentally benign approach has been developed for the preparation of dynamic, multiresponsive, and self-healing hydrogels from inexpensive bamboo pulp, poly(vinyl alcohol) (PVA), and borax. The microfibrillated cellulose (MFC) reinforced PVA–borax hydrogels were produced through a one-pot route in conjunction with ball milling and physical blending in tandem in aqueous medium. In this way, MFC particles could be efficiently generated and well-dispersed in a polymer matrix, and they have been verified by scanning electron microscopy. The rheology analysis indicated a close relationship between the mechanical strength and the MFC loading and ball milling time. Due to the dynamic equilibrium of the didiol–borax linkages and the reinforcement of MFC fibers, the hydrogels showed enhanced self-healing behavior and mechanical stiffness, which was also supported by rheology analyses. In addition, the hydrogels were found to be sensitive to the pH value. The hydrogels present a solvent or gel state with the change of pH value, and this sol–gel transfer can be repeated while maintaining the shape, further demonstrating the dynamic reversible behavior of the hydrogels.
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APPLIED SURFACE SCIENCE
·
2016
·
IF 3.15
Ting Lü,Shuang Zhang,Dongming Qi,Dong Zhang,George F. Vance,Hongting Zhao
Emulsified oil wastewaters, arisen from oil industry and oil spill accidents, cause severe environmental and ecological problems. In this study, a series of pH-sensitive magnetic nanomaterials (MNPs) were synthesized and characterized for their evaluation in separation of emulsified oil from aqueous environments. A coprecipitation method was used to produce Fe 3 O 4 magnetic nanoparticles that were coated in a 2-step process with first silica to form a surface for anchoring an (3-aminopropyl)triethoxysilane (APTES) molecular layer. Detailed studies were conducted on effects of MNPs dosage, APTES anchoring density ( D A ) and pH on oil-water separation performance of the synthetic MNPs. Results showed that, under both acidic and neutral conditions, MNPs with high D A exhibited enhanced oil-water separation performance, while under alkaline condition, the oil-water separation process was minimal. Alkaline conditions allowed the MNPs to be recycled up to 9 cycles without showing any significant decrease in oil-water separation efficiency. An examination of the oil-water separation mechanism found that electrostatic interaction and interfacial activity both played important roles in oil-water separation. In conclusion, pH-sensitive MNPs can be easily synthesized and recycled, providing a promising, cost-effective and environmentally-friendly process for the efficient treatment of emulsified oil wastewater.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2016
·Vol. 23
·期 19
·19266-19280
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IF 2.76
Yang Hui,Hu Yuanan,Cheng Hefa
Sorption of 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) on a range of dealuminated zeolites were investigated to understand the mechanism of their sorption on microporous minerals, while the influence of common metal cations, solution pH, and humic acid was also studied. Sorption of chlorophenols was found to increase with the hydrophobicity of the sorbates and that of the microporous minerals, indicating the important role of hydrophobic interactions, while sorption was also stronger in the micropores of narrower sizes because of greater enhancement of the dispersion interactions. The presence of metal cations could enhance chlorophenol sorption due to the additional electrostatic attraction between metal cations exchanged into the mineral micropores and the chlorophenolates, and this effect was apparent on the mineral sorbent with a high density of surface cations (2.62 sites/nm 2 ) in its micropores. Under circum-neutral or acidic conditions, neutral chlorophenol molecules adsorbed into the hydrophobic micropores through displacing the “loosely bound” water molecules, while their sorption was negligible under moderately alkaline conditions due to electrostatic repulsion between the negatively charged zeolite framework and anionic chlorophenolates. The influence of humic acid on sorption of chlorophenols on dealuminated Y zeolites suggests that its molecules did not block the micropores but created a secondary sorption sites by forming a “coating layer” on the external surface of the zeolites. These mechanistic insights could help better understand the interactions of ionizable chlorophenols and metal cations in mineral micropores and guide the selection and design of reusable microporous mineral sorbents for sorptive removal of chlorophenols from aqueous stream.
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MOLECULAR PHARMACEUTICS
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2016
·
IF 4.342
Haijun Zhao,Qian Li,Zehui Hong
Although PEGylation allows a drug delivery vehicle to have prolonged blood circulation time, it faces the problem of reduced cellular uptake. Removal of the polyethylene glycol (PEG)-shell at the appropriate time through tumor-microenvironment triggers could be a feasible solution to this problem. Here, paclitaxel (PTX)-loaded mixed micelles (PTX-mM) self-assembled from stearate-modified hyaluronic acid (SHA), mPEG-b-poly(β-amino ester) (mPEG-b-PAE), and ethylene acetyl-b-poly(β-amino ester) (EA-b-PAE) were developed. In the preparation of PTX-mM, SHA micelles were coated with EA-b-PAE followed by coloading of PTX and mPEG-b-PAE. PTX-mM were capable of extracellular pH-triggered PEG-detachment and poly(β-amino ester) (PAE)-mediated endosomal escape. When the pH was changed from pH 7.4 to pH 6.8, the particle size of PTX-mM significantly decreased from 97.5 ± 4.4 to 71.5 ± 2.3 nm. It also resulted in rapid and complete release of mPEG-b-PAE from PTX-mM as monitored using quartz crystal microbalance (QCM) technology. PTX-mM capable of PEG detachment provided significant enhancement of PTX accumulation in SKOV-3 cells compared to PEG nondetachable PTX-mM. Interestingly, intracellular transport studies using confocal laser scanning microscopy (CLSM) showed that EA-b-PAE could promote the escape of micelles from endolysosomes. The half-maximal inhibitory concentration (IC50) of PTX-mM against SKOV-3 cells was 5.7 μg/mL, and PTX-mM containing 20 μg/mL of PTX induced apoptosis in 53.0% of the cell population. PTX-mM exhibited a highly prolonged elimination half-life (t1/2, 2.83 ± 0.37 h) and improved area under the curve (AUC, 7724.82 ± 1190.75 ng/mL/h) than the PTX-loaded SHA micelles (PTX-M). Furthermore, PTX-mM showed the highest tumor inhibition rate (64.9%) and the longest survival time (53 days) against the SKOV-3 ovarian cancer xenograft models among all formulations. Taken together, the results suggested that PTX-mM have potential as an efficient anticancer formulation in treatment of ovarian cancer.
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BIOSENSORS & BIOELECTRONICS
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2016
·
IF 7.476
Huayu Xiong,Huiling Zheng,Wei Wang,Jichao Liang,Wei Wen,Xiuhua Zhang,Shengfu Wang
Herein, we report a convenient approach to purify water-soluble dihydrolipoic acid (DHLA)-capped Ag nanoclusters (Ag NCs) by pH-induced precipitation under acidic conditions. The fluorescence of Ag NCs could be completely recovered by re-dispersing the precipitate into a basic solution using DHLA and NaBH 4 as stabilizing ligands and etching reagent. DHLA-Ag NCs-doped agarose hydrogels have been prepared to monitor pH with a wide range from 8.0 to 4.0. When pH decreased, the fluorescence of the hydrogels under a UV lamp decreased and completely disappeared after pH 5. The DHLA-Ag NCs-doped agarose hydrogels biosensor showed low cytotoxicity and long stability. Accordingly, a fluorescent pH sensor for bacterial monitoring has been employed based on the “OFF–ON” signal switch of the Ag NCs-agarose hydrogel.
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SENSORS AND ACTUATORS B-CHEMICAL
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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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BIOMACROMOLECULES
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2016
·
IF 5.583
Wenliang Wang,Bo Wang,Xiaojing Ma,Sanrong Liu,Xudong Shang,Xifei Yu
Rapid cellular uptake and efficient drug release in tumor cells are two of the major challenges for cancer therapy. Herein, we designed and synthesized a novel pH-responsive polymer–drug conjugate system poly(2-(methacryloyloxy)ethyl choline phosphate)-b-poly(2-methoxy-2-oxoethyl methacrylate-hydrazide-doxorubicin) (PCP-Dox) to overcome these two challenges simultaneously. It has been proved that PCP-Dox can be easily and rapidly internalized by various cancer cells due to the strong interaction between multivalent choline phosphate (CP) groups and cell membranes. Furthermore, Dox, linked to the polymer carrier via acid-labile hydrazone bond, can be released from carriers due to the increased acidity in lysosome/endosome (pH 5.0–5.5) after the polymer prodrug was internalized into the cancer cells. The cell viability assay demonstrated that this novel polymer prodrug has shown enhanced cytotoxicity in various cancer cells, indicating its great potential as a new drug delivery system for cancer therapy.
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CHEMISTRY OF MATERIALS
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2016
·
IF 9.407
Qiuju Li,Min Chen,Daoyong Chen,Limin Wu
Nano drug delivery systems have attracted much research and clinical interest but they remain challenging with respect to developing controllable, nontoxic, biocompatible and biodegradable nanocarriers. Herein, we report the first pH- and glutathione (GSH)-responsive diphenylalanine (FF)-based hybrid spheres using natural alginate dialdehyde (ADA) as the cross-linker to induce self-assembly of FF and an in situ reducer of Au3+ ions into Au nanoparticles (Au NPs). Not only is the synthesis simple and high-yielding, but also these biocompatible hybrid spheres can encapsulate more than 95% of hydrophobic drug (camptothecin, CPT). Moreover, the CPT-loaded carriers are stable under normal physiological environments, and have excellent pH- and GSH-responsive release at pH 5.0 with 10 mM GSH, which is similar to the tumor microenvironment. Also, these nanocarriers can be taken up by cancer cells and have greater cytotoxicity than free drugs. These attributes make nanospheres very promising for drug loading and delivery, and the method may be used for synthesis of other natural nanospheres as delivery systems.
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Journal of Materials Chemistry B
·
2017
·Vol. 5
·期 42
·8399-8407
·
IF 4.543
Dan Zhao,Shujie Ma,Xiaoqing Yi,Sixue Cheng,Renxi Zhuo,Feng Li
Herein, a pH and redox dual-sensitive core-crosslinked targeting nanocarrier was prepared and used for co-delivery of doxorubicin (DOX) and tariquidar (TQR). The nanocarrier not only had excellent stability but also prevented the leakage of the drug in the normal physiological environment efficiently. Meanwhile, the targeting function of nanocarriers could also be suppressed in the normal physiological environment, protecting nanocarriers from being captured by RAW264.7 cells. Under mild acidic conditions, the targeting function was regained, leading to an effective tumor cell uptake of the nanocarrier. Furthermore, reduction-responsive drug release would occur in the cytoplasm due to the collapse of the reduction-sensitive crosslinked structure in the nanocarrier. By means of ligand–receptor mediated endocytosis and TQR-mediated glycoprotein (P-gp) inhibition, the IC50 value of DOX to MCF-7/ADR cells reduced from more than 100 μg mL−1 to 8.55 μg mL−1, exhibiting great potential in overcoming drug resistance.
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RSC Advances
·
2016
·Vol. 6
·期 100
·97684-97693
·
IF 3.289
Yongchao Yao,Deqiu Xu,Chang Liu,Yayuan Guan,Jiya Zhang,Yuling Su,Lili Zhao,Fancui Meng,Jianbin Luo
Biodegradable multi-blocked polyurethane (PU) based micelles with a hydrophilic PEG corona were extensively studied for anti-cancer drug delivery systems. The hydrophilic PEG segment usually incorporated as a soft segment or as an end capping reagent, which has difficulty forming a dense PEG coating with a brush like conformation due to the low mobility of the PEG domains at the soft segment and the low amount of the PEG at the end of PU chains. In the present study, biodegradable pH sensitive polyurethane micelles with a dense brush like coating of PEG were prepared by a new kind of PEG grafted polyurethanes (PEG-g-PU) which were synthesized using PEGylated diethanolamine (MPEG-DEAM) as a chain extender. The high mobility of pendant MPEG in PEG-g-PU results in the formation of a dense and brush like PEG corona on the PEG-g-PU micelles. Meanwhile the MPEG attached on the hard segment will transfer the diethanolamine (DEAM) to the surface of nanoparticles during the self-assembly process and the DEAM render the particles with positive charges which potentially enhances cellular uptake and endosomal escape. DLS, TEM and AFM showed that a dense PEG domain was formed on the surface of PEG-g-PU micelles while no obvious PEG microdomain was observed for the other two kinds of micelles. FTIR and DSC results demonstrated the enhanced microphase separation of PEG-g-PU micelles compared with PEG-g-PU bulk materials and the other two contrast PU micelles, i.e. PEG-b-PU and PEG-c-PU. Paclitaxel (PTX) was chosen as a model hydrophobic drug to evaluate the loading and pH-triggered release of the PU micelles. The enhanced cytotoxicity of PTX-loaded PEG-g-PU-3 micelles against H460 cancer cells reveals that they are more potent for intracellular delivery of PTX as compared to PEG-b-PU-3 and PEG-c-PU-3 micelles.
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Nanoscale
·
2017
·Vol. 9
·期 40
·15673-15684
·
IF 7.367
T. M. Chen,X. M. Tian,L. Huang,J. Xiao,G. W. Yang
Nanodiamonds (NDs) have recently become a focus of interest from the viewpoints of both science and technology. Their intriguing properties make them suitable as biologically active substrates, in biosensor applications as well as diagnostic and therapeutic biomedical imaging probes. Here, we demonstrate that NDs, as oxidation and reduction catalysts, possess intrinsic enzyme mimetic properties of oxidase, peroxidase and catalase, and these behaviors can be switched by modulating the pH value. NDs not only catalyze the reduction of oxygen (O2) and hydrogen peroxide (H2O2) at acidic pH, but also catalyze the dismutation decomposition of H2O2 to produce O2 at alkaline pH. It was proposed that the molecular mechanism of their peroxidase-like activity is electron-transfer acceleration, the source of which is likely derived from oxygen containing functional groups on their surface. Based on the color reaction, a nanodiamond-based enzyme linked immunosorbent assay (ELISA) was established for the detection of immunoglobulin G (IgG). Surprisingly, NDs display an excellent antioxidant activity due to the protective effect against H2O2-induced cellular oxidative damage. These findings make NDs a promising enzyme mimetic candidate and expand their applications in biocatalysis, bioassays and nano-biomedicine.
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