oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 167 )

2018 ( 1485 )

2017 ( 1337 )

2016 ( 1377 )

Custom range...

Search Results: 1 - 10 of 80817 matches for " Liu XY "
All listed articles are free for downloading (OA Articles)
Page 1 /80817
Display every page Item
MicroRNA-141 is downregulated in human renal cell carcinoma and regulates cell survival by targeting CDC25B
Yu XY,Zhang Z,Liu J,Zhan B
OncoTargets and Therapy , 2013,
Abstract: Xiu-yue Yu, Zhe Zhang, Jiao Liu, Bo Zhan, Chui-ze Kong Department of Urology, the First Hospital of China Medical University, Shenyang, People’s Republic of China Background/objective: MicroRNAs (miRNAs) are small noncoding RNAs (ribonucleic acids), approximately 22 nucleotides in length, that function as regulators of gene expression. Dysregulation of miRNAs has been associated with the initiation and progression of oncogenesis in humans. The cell division cycle (CDC)25 phosphatases are important regulators of the cell cycle. Their abnormal expression detected in a number of tumors implies that their dysregulation is involved in malignant transformation. Methods: Using miRNA target prediction software, we found that miR-141 could target the 3′ untranslated region (3′UTR) sequence of CDC25B. To shed light on the role of miR-141 in renal cell carcinogenesis, the expression of miR-141 was examined by real-time polymerase chain reaction (RT-PCR) in renal cell carcinoma and normal tissues. The impact of miR-141 re-expression on 769-P cells was analyzed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony-forming assay. A luciferase reporter assay was applied to prove the functionality of the miR-141 binding site. Results: miR-141 is significantly downregulated in renal cell carcinoma. miR-141 re-expression suppressed cell growth in 769-P cells. Luciferase expression from a reporter vector containing the CDC25B-3'UTR was decreased when this construct was transfected with miR-141 in 769-P cells. The overexpression of miR-141 suppressed the endogenous CDC25B protein level in 769-P cells. Conclusion: For the first time, we demonstrated that CDC25B is a direct target of miR-141 in renal cell carcinoma. The transcriptional loss of miR-141 and the resultant increase in CDC25B expression facilitates increased genomic instability at an early stage of renal cell carcinoma development. Keywords: carcinogenesis, 769-P, target, MicroRNAs, proliferation, luciferase
Degradable copolymer based on amphiphilic N-octyl-N-quatenary chitosan and low-molecular weight polyethylenimine for gene delivery
Liu CC, Zhu Q, Wu WH, Xu XL, Wang XY, Gao S, Liu KH
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S36179
Abstract: radable copolymer based on amphiphilic N-octyl-N-quatenary chitosan and low-molecular weight polyethylenimine for gene delivery Original Research (1427) Total Article Views Authors: Liu CC, Zhu Q, Wu WH, Xu XL, Wang XY, Gao S, Liu KH Published Date October 2012 Volume 2012:7 Pages 5339 - 5350 DOI: http://dx.doi.org/10.2147/IJN.S36179 Received: 20 July 2012 Accepted: 22 August 2012 Published: 08 October 2012 Chengchu Liu,1,2,* Qing Zhu,1,* Wenhui Wu,1 Xiaolin Xu,1 Xiaoyu Wang,3 Shen Gao,3 Kehai Liu1 1Department of Biopharmaceutics, College of Food Science and Technology, Shanghai Ocean University, Shanghai, China; 2Shanghai Engineering Research Center of Aquatic-Product Processing and Preservation, Shanghai, China; 3Department of Pharmaceutics, Changhai Hospital, Second Military Medical University, Shanghai China *The first two authors contributed equally to this work Background: Chitosan shows particularly high biocompatibility and fairly low cytotoxicity. However, chitosan is insoluble at physiological pH. Moreover, it lacks charge, so shows poor transfection. In order to develop a new type of gene vector with high transfection efficiency and low cytotoxicity, amphiphilic chitosan was synthesized and linked with low-molecular weight polyethylenimine (PEI). Methods: We first synthesized amphiphilic chitosan – N-octyl-N-quatenary chitosan (OTMCS), then prepared degradable PEI derivates by cross-linking low-molecular weight PEI with amphiphilic chitosan to produce a new polymeric gene vector (OTMCS–PEI). The new gene vector was characterized by various physicochemical methods. We also determined its cytotoxicity and gene transfecton efficiency in vitro and in vivo. Results: The vector showed controlled degradation. It was very stable and showed excellent buffering capacity. The particle sizes of the OTMCS–PEI/DNA complexes were around 150–200 nm with proper zeta potentials from 10 mV to 30 mV. The polymer could protect plasmid DNA from being digested by DNase I at a concentration of 2.25 U DNase I/μg DNA. Furthermore, they were resistant to dissociation induced by 50% fetal bovine serum and 1100 μg/mL sodium heparin. OTMCS–PEI revealed lower cytotoxicity, even at higher doses. Compared with PEI 25 KDa, the OTMCS–PEI/DNA complexes also showed higher transfection efficiency in vitro and in vivo. Conclusion: OTMCS–PEI was a potential candidate as a safe and efficient gene vector for gene therapy.
Molecular cloning and characterization of a novel expressed sequence tag (EST) associated with fecundity in goats
YQ He, J Kong, XK Ma, CX Zhang, XY Liu, HQ Chen
African Journal of Biotechnology , 2010,
Abstract: To screen the genes controlling the fecundity traits in goats, a DDRT-PCR technique was applied. We found a new EST which highly expressed in Chinese native prolific goat breed, Haimen goats. There exists a difference of EST expression level between the prolific and non-prolific goat breed, indicating EST might associate to fecundity in goats. A full-length cDNA with 2253 base pairs was obtained by the 3’- and 5’-RACE method based on the EST sequence encoding a protein segment of 201 amino acid residues. Tissue specific distribution and sequence analysis implicated the likely involvement of EST in the regulation of the hormones related to fecundity.
Biofunctionalization of a titanium surface with a nano-sawtooth structure regulates the behavior of rat bone marrow mesenchymal stem cells
Zhang WJ, Li ZH, Liu Y, Ye DX, Li JH, Xu LY, Wei B, Zhang XL, Liu XY, Jiang XQ
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S33575
Abstract: iofunctionalization of a titanium surface with a nano-sawtooth structure regulates the behavior of rat bone marrow mesenchymal stem cells Original Research (2126) Total Article Views Authors: Zhang WJ, Li ZH, Liu Y, Ye DX, Li JH, Xu LY, Wei B, Zhang XL, Liu XY, Jiang XQ Published Date August 2012 Volume 2012:7 Pages 4459 - 4472 DOI: http://dx.doi.org/10.2147/IJN.S33575 Received: 04 May 2012 Accepted: 12 July 2012 Published: 13 August 2012 Wenjie Zhang,1,2 Zihui Li,3 Yan Liu,1,2 Dongxia Ye,4 Jinhua Li,3 Lianyi Xu,1,2 Bin Wei,1 Xiuli Zhang,2 Xuanyong Liu,3,* Xinquan Jiang,1,2,* 1Department of Prosthodontics, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University, School of Medicine, 2Oral Bioengineering Laboratory, Shanghai Research Institute of Stomatology, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University, School of Medicine, Shanghai Key Laboratory of Stomatology, 3State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 4Shanghai Research Institute of Stomatology, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China *Joint principal authors of this work Background: The topography of an implant surface can serve as a powerful signaling cue for attached cells and can enhance the quality of osseointegration. A series of improved implant surfaces functionalized with nanoscale structures have been fabricated using various methods. Methods: In this study, using an H2O2 process, we fabricated two size-controllable sawtooth-like nanostructures with different dimensions on a titanium surface. The effects of the two nano-sawtooth structures on rat bone marrow mesenchymal stem cells (BMMSCs) were evaluated without the addition of osteoinductive chemical factors. Results: These new surface modifications did not adversely affect cell viability, and rat BMMSCs demonstrated a greater increase in proliferation ability on the surfaces of the nano-sawtooth structures than on a control plate. Furthermore, upregulated expression of osteogenic-related genes and proteins indicated that the nano-sawtooth structures promote osteoblastic differentiation of rat BMMSCs. Importantly, the large nano-sawtooth structure resulted in the greatest cell responses, including increased adhesion, proliferation, and differentiation. Conclusion: The enhanced adhesion, proliferation, and osteogenic differentiation abilities of rat BMMSCs on the nano-sawtooth structures suggest the potential to induce improvements in bone-titanium integration in vivo. Our study reveals the key role played by the nano-sawtooth structures on a titanium surface for the fate of rat BMMSCs and provides insights into the study of stem cell-nanostructure relationships and the related design of improved biomedical implant surfaces.
SURFACE ANALYSIS OF ALUMINUM ALLOYS INFLUENCED BY SULFATE REDUCING BACTERIA
SURFACE ANALYSIS OF ALUMINUM ALLOYS INFLUENCED BY SULFATE- REDUCING BACTERIA

X L Wu,JH Liu,XY Chen,
X. L. Wu
,J.H. Liu and X.Y. Chen

金属学报(英文版) , 1999,
Abstract: The morphology and chemical compositions of surface and corrosion phases for two aluminum alloys(7075 and 2024 ) in the aqueous mediums containing sulfate reducing bacteria(SRB) were studied by the methods of scanning electron microscopy (SEM) and energy dispersive x ray analysis (EDXA). The results showed that serious pitting corrosion took place when aluminum alloys were exposed in the mediums containing SRB, whereas no pitting corrosion were found on the surfaces of aluminum alloys only exposed in blank mediums non containing SRB. It was demonstrated with EDXA that corrosion of aluminum alloys exposed in the solutions containing SRB, whereas the corrosion in the solution non containing microorganisms was attributed to the presence of chloride ions(Cl ).
A comparative study of three ternary complexes prepared in different mixing orders of siRNA/redox-responsive hyperbranched poly (amido amine)/hyaluronic acid
Chen CJ, Zhao ZX, Wang JC, Zhao EY, Gao LY, Zhou SF, Liu XY, Lu WL, Zhang Q
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S32676
Abstract: comparative study of three ternary complexes prepared in different mixing orders of siRNA/redox-responsive hyperbranched poly (amido amine)/hyaluronic acid Original Research (2095) Total Article Views Authors: Chen CJ, Zhao ZX, Wang JC, Zhao EY, Gao LY, Zhou SF, Liu XY, Lu WL, Zhang Q Published Date July 2012 Volume 2012:7 Pages 3837 - 3849 DOI: http://dx.doi.org/10.2147/IJN.S32676 Received: 06 April 2012 Accepted: 14 May 2012 Published: 18 July 2012 Cheng-Jun Chen,1 Zhi-Xia Zhao,1 Jian-Cheng Wang,1 En-Yu Zhao,1 Ling-Yan Gao,1 Shu-Feng Zhou,2 Xiao-Yan Liu,1 Wan-Liang Lu,1 Qiang Zhang1 1State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmaceutics, School of Pharmaceutical Science, Peking University, Beijing, People’s Republic of China; 2Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA Abstract: In this study, a novel redox-responsive hyperbranched poly(amido amine) (named PCD) was synthesized and used as a cationic polymer to form a ternary complex with small interfering RNA (siRNA) and hyaluronic acid (HA) for siRNA delivery. Here, it is hypothesized that different mixing orders result in different assembly structures, which may affect the siRNA delivery efficiency. To investigate the effects of mixing orders on siRNA delivery efficiency in two human breast cancer cell lines, three ternary complexes with different mixing orders of siRNA/PCD/HA were prepared and characterized: mixing order I (initially prepared siRNA/PCD binary complex further coated by negatively charged HA), mixing order II (initially prepared HA/PCD binary complex further incubated with siRNA), and mixing order III (initially prepared siRNA/HA mixture further electrostatically compacted by positively charged PCD). With an optimized siRNA/PCD/HA charge ratio of 1/20/16, the particle sizes and zeta potentials of these ternary complexes were 124.8 nm and 27.3 mV (mixing order I), 147.5 nm and 29.9 mV (mixing order II), and 128.8 nm and 19.4 mV (mixing order III). Also, the effects on stability, cellular uptake, and gene silencing efficiency of siRNA formulated in ternary complexes with different mixing orders were investigated. The results showed that mixing orders I and III displayed better siRNA transfection and protection than mixing order II in human breast cancer MCF-7 and MDA-MB-231 cells. More interesting, at the siRNA/PCD/HA charge ratio of 1/20/16, the gene silencing effects on vascular endothelial growth factor expression in MDA-MB-231 cells were as follows: mixing order III > mixing order I > mixing order II. Based on these results, a likely explanation for the difference in functionality dependent on mixing orders is the formation of different assembly structures. These results may help future optimization of siRNA ternary complexes for achieving better delivery efficiencies, especially for target-specific siRNA delivery to cells with HA receptor overexpression.
Pharmacokinetics, tissue distribution, and metabolites of a polyvinylpyrrolidone-coated norcantharidin chitosan nanoparticle formulation in rats and mice, using LC-MS/MS
Ding XY, Hong CJ, Liu Y, Gu ZL, Xing KL, Zhu AJ, Chen WL, Shi LS, Zhang XN, Zhang Q
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S29696
Abstract: rmacokinetics, tissue distribution, and metabolites of a polyvinylpyrrolidone-coated norcantharidin chitosan nanoparticle formulation in rats and mice, using LC-MS/MS Original Research (3450) Total Article Views Authors: Ding XY, Hong CJ, Liu Y, Gu ZL, Xing KL, Zhu AJ, Chen WL, Shi LS, Zhang XN, Zhang Q Published Date April 2012 Volume 2012:7 Pages 1723 - 1735 DOI: http://dx.doi.org/10.2147/IJN.S29696 Received: 04 January 2012 Accepted: 02 February 2012 Published: 02 April 2012 Xin-Yuan Ding1, Cheng-Jiao Hong2, Yang Liu1, Zong-Lin Gu1, Kong-Lang Xing1, Ai-Jun Zhu1, Wei-Liang Chen1, Lin-Seng Shi1, Xue-Nong Zhang1, Qiang Zhang3 1Department of Pharmaceutics, College of Pharmaceutical science, Soochow University, Suzhou, 2Jiang Su Provincial Key Laboratory of Radiation Medicine and Protection, Suzhou, 3Department of Pharmaceutics, School of Pharmaceutical Science, Peking University, Beijing, People’s Republic of China Abstract: A novel formulation containing polyvinylpyrrolidone (PVP) K30-coated norcantharidin (NCTD) chitosan nanoparticles (PVP–NCTD–NPs) was prepared by ionic gelation between chitosan and sodium tripolyphosphate. The average particle size of the PVP–NCTD–NPs produced was 140.03 ± 6.23 nm; entrapment efficiency was 56.33% ± 1.41%; and drug-loading efficiency was 8.38% ± 0.56%. The surface morphology of NCTD nanoparticles (NPs) coated with PVP K30 was characterized using various analytical techniques, including X-ray diffraction and atomic force microscopy. NCTD and its metabolites were analyzed using a sensitive and specific liquid chromatography-tandem mass spectrometry method with samples from mice and rats. The results indicated the importance of the PVP coating in controlling the shape and improving the entrapment efficiency of the NPs. Pharmacokinetic profiles of the NCTD group and PVP–NCTD–NP group, after oral and intravenous administration in rats, revealed that relative bioavailabilities were 173.3% and 325.5%, respectively. The elimination half-life increased, and there was an obvious decrease in clearance. The tissue distribution of NCTD in mice after the intravenous administration of both formulations was investigated. The drug was not quantifiable at 6 hours in all tissues except for the liver and kidneys. The distribution of the drug in the liver and bile was notably improved in the PVP–NCTD–NP group. The metabolites and excretion properties of NCTD were investigated by analyzing rat feces and urine samples, collected after oral administration. A prototype drug and two metabolites were found in the feces, and seven metabolites in the urine. The primary elimination route of NCTD was via the urine. The quantity of the parent drug eliminated in the feces of the PVP–NCTD–NP group, was 32 times greater than that of the NCTD group, indicating that the NPs dramatically increased the reduction quantity from liver to bile. We conclude that PVP–NCTD–NPs are an adequate formulation for enhancing the absorption of NCTD, and significa
Effects of a hybrid micro/nanorod topography-modified titanium implant on adhesion and osteogenic differentiation in rat bone marrow mesenchymal stem cells
Zhang WJ, Li ZH, Huang QF, Xu L, Li JH, Jin YQ, Wang GF, Liu XY, Jiang XQ
International Journal of Nanomedicine , 2013, DOI: http://dx.doi.org/10.2147/IJN.S39357
Abstract: ts of a hybrid micro/nanorod topography-modified titanium implant on adhesion and osteogenic differentiation in rat bone marrow mesenchymal stem cells Original Research (1099) Total Article Views Authors: Zhang WJ, Li ZH, Huang QF, Xu L, Li JH, Jin YQ, Wang GF, Liu XY, Jiang XQ Published Date January 2013 Volume 2013:8 Pages 257 - 265 DOI: http://dx.doi.org/10.2147/IJN.S39357 Received: 19 October 2012 Accepted: 02 December 2012 Published: 11 January 2013 Wenjie Zhang,1,2,* Zihui Li,3,* Qingfeng Huang,1 Ling Xu,1 Jinhua Li,3 Yuqin Jin,1,2 Guifang Wang,1,2 Xuanyong Liu,2 Xinquan Jiang1 1Department of Prosthodontics, 2Oral Bioengineering Laboratory, Shanghai Research Institute of Stomatology, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University, School of Medicine, 3State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China *These authors contributed equally to this work Background and methods: Various methods have been used to modify titanium implant surfaces with the aim of achieving better osseointegration. In this study, we fabricated a clustered nanorod structure on an acid-etched, microstructured titanium plate surface using hydrogen peroxide. We also evaluated biofunctionalization of the hybrid micro/nanorod topography on rat bone marrow mesenchymal stem cells. Scanning electron microscopy and x-ray diffraction were used to investigate the surface topography and phase composition of the modified titanium plate. Rat bone marrow mesenchymal stem cells were cultured and seeded on the plate. The adhesion ability of the cells was then assayed by cell counting at one, 4, and 24 hours after cell seeding, and expression of adhesion-related protein integrin β1 was detected by immunofluorescence. In addition, a polymerase chain reaction assay, alkaline phosphatase and Alizarin Red S staining assays, and osteopontin and osteocalcin immunofluorescence analyses were used to evaluate the osteogenic differentiation behavior of the cells. Results: The hybrid micro/nanoscale texture formed on the titanium surface enhanced the initial adhesion activity of the rat bone marrow mesenchymal stem cells. Importantly, the hierarchical structure promoted osteogenic differentiation of these cells. Conclusion: This study suggests that a hybrid micro/nanorod topography on a titanium surface fabricated by treatment with hydrogen peroxide followed by acid etching might facilitate osseointegration of a titanium implant in vivo.
Novel norcantharidin-loaded liver targeting chitosan nanoparticles to enhance intestinal absorption
Bei YY, Chen XY, Liu Y, Xu JY, Wang WJ, Gu ZL, Xing KL, Zhu AJ, Chen WL, Shi LS, Wang Q, Zhang XN, Zhang Q
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S29958
Abstract: vel norcantharidin-loaded liver targeting chitosan nanoparticles to enhance intestinal absorption Original Research (3138) Total Article Views Authors: Bei YY, Chen XY, Liu Y, Xu JY, Wang WJ, Gu ZL, Xing KL, Zhu AJ, Chen WL, Shi LS, Wang Q, Zhang XN, Zhang Q Published Date April 2012 Volume 2012:7 Pages 1819 - 1827 DOI: http://dx.doi.org/10.2147/IJN.S29958 Received: 15 January 2012 Accepted: 03 February 2012 Published: 03 April 2012 Yong-yan Bei1, Xiao-yan Chen1, Yang Liu1, Jing-yu Xu1, Wen-juan Wang1, Zong-lin Gu1, Kong-lang Xing1, Ai-jun Zhu1, Wei-liang Chen1, Lin-seng Shi1, Qin Wang1, Xue-nong Zhang1, Qiang Zhang2 1College of Pharmaceutical Science, Soochow University, Suzhou, 2Department of Pharmaceutics, School of Pharmaceutical Science, Peking University, Beijing, People's Republic of China Abstract: In this paper, two novel liver-targeting nanoparticles, norcantharidin-loaded chitosan nanoparticles (NCTD-CS-NPs) and norcantharidin-associated galactosylated chitosan nanoparticles (NCTD-GC-NPs), were prepared using ionic cross-linkage. The physical properties, particle size, encapsulation efficiency, and drug release characteristics of the nanoparticles were investigated in vitro. To investigate the intestinal absorption mechanisms of the two preparations, a series of experiments was carried out, including in situ circulation method, in vitro everted gut sacs, and Ussing chamber perfusion technique. The absorption rate constants (Ka) of NCTD at different segments were found to be duodenum > jejunum > ileum > colon. The concentration had no distinctive effect on absorption kinetics, suggesting that drug absorption is not dose-dependent. The transport of NCTD was found to be inhibited by P-glycoprotein (P-gp) inhibitor, indicating that NCTD might be the substrate of P-gp. The order of the absorption enhancer effects were as follows: low molecular weight chitosan (CS-8kDa) . high molecular weight chitosan (CS-30kDa) > Poloxamer > sodium dodecyl sulfate (SDS) > sodium deoxycholate (SDCh). The results indicate that the chitosan nanoparticles can improve intestinal absorption of NCTD.
Preparation, characterization and application of star-shaped PCL/PEG micelles for the delivery of doxorubicin in the treatment of colon cancer
Gao X, Wang BL, Wei XW, Rao W, Ai F, Zhao F, Men K, Yang BW, Liu XY, Huang MJ, Gou ML, Qian ZY, Huang N, Wei YQ
International Journal of Nanomedicine , 2013, DOI: http://dx.doi.org/10.2147/IJN.S39532
Abstract: eparation, characterization and application of star-shaped PCL/PEG micelles for the delivery of doxorubicin in the treatment of colon cancer Original Research (812) Total Article Views Authors: Gao X, Wang BL, Wei XW, Rao W, Ai F, Zhao F, Men K, Yang BW, Liu XY, Huang MJ, Gou ML, Qian ZY, Huang N, Wei YQ Published Date March 2013 Volume 2013:8 Pages 971 - 982 DOI: http://dx.doi.org/10.2147/IJN.S39532 Received: 24 October 2012 Accepted: 24 November 2012 Published: 08 March 2013 Xiang Gao,1 BiLan Wang,1 XiaWei Wei,1 Wang Rao,2 Fang Ai,2 Fen Zhao,2 Ke Men,1 Bowen Yang,1 Xingyu Liu,1 Meijuan Huang,1 Maling Gou,1 ZhiYong Qian,1 Ning Huang,1 Yuquan Wei1 1Department of Pathophysiology, College of Preclinical and Forensic Medical Sciences, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, People's Republic of China; 2Department of Surgery, First Affiliated Hospital, Xinxiang Medical School, Xinxiang, People's Republic of China Abstract: Star-shaped polymer micelles have good stability against dilution with water, showing promising application in drug delivery. In this work, biodegradable micelles made from star-shaped poly (ε-caprolactone)/poly(ethylene glycol) (PCL/PEG) copolymer were prepared and used to deliver doxorubicin (Dox) in vitro and in vivo. First, an acrylated monomethoxy poly (ethylene glycol)-poly (ε-caprolactone) (MPEG-PCL) diblock copolymer was synthesized, which then self-assembled into micelles, with a core-shell structure, in water. Then, the double bonds at the end of the PCL blocks were conjugated together by radical polymerization, forming star-shaped MPEG-PCL (SSMPEG-PCL) micelles. These SSMPEG-PCL micelles were monodispersed (polydispersity index = 0.11), with mean diameter of ≈25 nm, in water. Blank SSMPEG-PCL micelles had little cytotoxicity and did not induce obvious hemolysis in vitro. The critical micelle concentration of the SSMPEG-PCL micelles was five times lower than that of the MPEG-PCL micelles. Dox was directly loaded into SSMPEG-PCL micelles by a pH-induced self-assembly method. Dox loading did not significantly affect the particle size of SSMPEG-PCL micelles. Dox-loaded SSMPEG-PCL (Dox/SSMPEG-PCL) micelles slowly released Dox in vitro, and the Dox release at pH 5.5 was faster than that at pH 7.0. Also, encapsulation of Dox in SSMPEG-PCL micelles enhanced the anticancer activity of Dox in vitro. Furthermore, the therapeutic efficiency of Dox/SSMPEG-PCL on colon cancer mouse model was evaluated. Dox/SSMPEG-PCL caused a more significant inhibitory effect on tumor growth than did free Dox or controls (P < 0.05), which indicated that Dox/SSMPEG-PCL had enhanced anticolon cancer activity in vivo. Analysis with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) showed that Dox/SSMPEG-PCL induced more tumor cell apoptosis than free Dox or controls. These results suggested that SSMPEG-PCL micelles have promising application
Page 1 /80817
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.