Co-reporter:Zhenqing Hou, Yang Li, Yuancan Huang, Chunxiao Zhou, Jinyan Lin, Yixiao Wang, Fei Cui, Shuifan Zhou, Mengmeng Jia, Shefang Ye, and Qiqing Zhang
Molecular Pharmaceutics 2013 Volume 10(Issue 1) pp:90-101
Publication Date(Web):November 16, 2012
DOI:10.1021/mp300489p
A novel formulation system of phytosomes loaded with mitomycin C–soybean phosphatidylcholine (MMC–SPC) complex (MMC-loaded phytosomes) was prepared by a solvent evaporation method combined with a nanoprecipitation technique for the purpose of development of an MMC drug delivery system. The MMC-loaded phytosomes were evaluated by average particle size, zeta-potential, and residual drug-loading content as well as an in vitro drug release profile. Furthermore, in vitro stability tests and in vitro/vivo biological evaluations of the MMC-loaded phytosomes were performed. DSC, FTIR, and XRD demonstrated that MMC interacted physically with SPC within the phytosomes. DLS and ELS described a dispersion with an average particle size of 210.87 nm, a narrow size distribution (PDI 0.251), and a zeta-potential of −33.38 mV. SEM, TEM, and AFM images showed that the MMC-loaded phytosomes were spherical and intact vesicles. In vitro stability tests demonstrated that the average particle size and residual drug-loading content of the MMC-loaded phytosomes had no evident change at different storage conditions. In vitro drug release profiles indicated biphasic behavior with an initial burst release, followed by a subsequent prolonged sustained release. In vitro cytotoxicity assays with H22 cells showed that the MMC-loaded phytosomes had remarkable cytotoxicity. In vivo antitumor effect of the MMC-loaded phytosomes also revealed a dose-dependent and superior curative inhibitory effect on tumor growth without loss of body weight compared to free MMC. Histopathological analysis of specimens taken from tumor tissues indicated that MMC-loaded phytosomes had lethal effect to hepatoma cell. These findings suggested that the MMC-loaded phytosomes can serve as a promising and effective formulation for drug delivery and cancer therapy.Keywords: complex; delivery vehicle; mitomycin C; phytosomes; soybean phosphatidylcholine;
Co-reporter:Qingqing Yao, Patcharakamon Nooeaid, Judith A. Roether, Yanming Dong, Qiqing Zhang, Aldo R. Boccaccini
Ceramics International 2013 Volume 39(Issue 7) pp:7517-7522
Publication Date(Web):September 2013
DOI:10.1016/j.ceramint.2013.03.002
Abstract
Highly porous scaffolds have been fabricated by the replication technique using 45S5 Bioglass® (BG) powder. For the purpose of imparting a local drug release capability, the scaffolds were coated with polycaprolactone and vancomycin-loaded chitosan by a two-step procedure. Bare BG scaffolds loaded with vancomycin via a direct immersion method were used as control. The chemical composition and microstructure of bare and coated scaffolds were characterized through Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), respectively. The mechanical properties of the coated scaffolds were significantly improved compared with uncoated scaffolds; the compressive strength values of the coated scaffolds were about 3 times and the area under the stress–strain curve was about 7 times higher than those of the uncoated scaffolds. The scaffolds degradation behavior and the drug release profiles were studied in a phosphate buffered saline (PBS) solution. There was a sharp release of the drug in the first few hours (8 h) for both bare and coated scaffolds. For the bare scaffolds the drug was released completely in 24 h. However, the coated scaffolds showed a sustained release in a period of 11 days, suggesting the potential of the present polymer coated BG scaffolds to be used as bone tissue scaffolds with drug carrier and delivery ability.
Co-reporter:Yixiao Wang, Zhenqing Hou, Hao Guo, Lihua Shen, Gongxin Wang, Fei Cui, Qiqing Zhang
Materials Letters 2013 Volume 91() pp:107-110
Publication Date(Web):15 January 2013
DOI:10.1016/j.matlet.2012.09.070
Highly crystalline ZnO with hexagonal rod-like morphology was fabricated by a carboxylate-modified PS (polystyrene)-assisted hydrothermal process. The reactions could be carried out under mild conditions in an inexpensive and environmentally-friendly way, and was suitable for large scale production. The as-prepared ZnO nanorods, with lengths of 200–280 nm and diameters of 100–130 nm, possessed a single-crystal hexagonal structure and grew along the [001] direction. Furthermore, the results revealed that the carboxylate-modified PS played a vital role in the synthesis of rod-like structure ZnO. In addition, photoluminescence (PL) spectrum showed a strong UV emission peak of ZnO samples at room temperature.Highlights► Highly crystalline ZnO with hexagonal rod-like morphology was fabricated by a carboxylate-modified PS (polystyrene)-assisted hydrothermal process. ► The reactions could be carried out under mild conditions in an inexpensive cheaper and environmentally-friendly way, and was suitable for large scale production. ► Carboxylate-modified PS played a vital role in the synthesis of rod-like structure ZnO. ► Photoluminescence (PL) spectrum showed a strong UV emission peak of ZnO samples at room temperature.
Co-reporter:Xi-ming Pu, Kai Wei, Qi-qing Zhang
Materials Letters 2013 Volume 94() pp:169-171
Publication Date(Web):1 March 2013
DOI:10.1016/j.matlet.2012.12.009
Chitosan/hydroxyapatite composite rods are good candidates as temporary mechanical supports in bone regeneration; however the mechanical properties of this kind of materials should be improved. In this work, chitosan/hydroxyapatite composite rods with multilayer structure were reinforced using a bio-crosslinker to improve their mechanical properties and anti-degradation ability. The SEM results revealed that the composite rods had a tree-ring structure. The bending strength and bending modulus of the crosslinked rods could arrive at 161 MPa and 7.2 GPa, respectively, increased by 59.4% and 26.3% compared with uncrosslinked ones (p<0.05). The enzymatic degradation studies indicated that genipin crosslinking could effectively enhance the biostability of the composite rods. Consequently, genipin-crosslinked chitosan/hydroxyapatite composite rods with excellent mechanical properties would be a novel device used for internal fixation of bone fracture.Highlights► Genipin/chitosan/hydroxyapatite rods with annual ring structure were synthesized. ► The mechanical properties of the composite rods were enhanced by crosslinking. ► The introduction of genipin has slowed down the biodegradation rate of the rods.
Co-reporter:Xi Zhou, Yan Wang, Lubin Zhong, Shixiong Bao, Yu Han, Lei Ren and Qiqing Zhang
Nanoscale 2012 vol. 4(Issue 20) pp:6256-6259
Publication Date(Web):20 Aug 2012
DOI:10.1039/C2NR32022C
Through the different functionalities on Au nanosphere (AuNSs) and Au nanorod (AuNRs) surfaces, we successfully control AuNSs attachment onto either the end or side surface of anisotropic AuNRs via bio-recognition, and then consciously construct side-by-side or end-to-end assembly nanostructures. This study provides a feasible approach to organize nanoparticles with different morphologies into controllable assembly geometries, which can potentially benefit the construction of future nanodevices.
Co-reporter:Xuemin Li;Jianhua Wang;Guanghao Su;Zhimin Zhou;Jiawei Shi;Lingrong Liu;Man Guan
Journal of Biomedical Materials Research Part A 2012 Volume 100A( Issue 2) pp:396-405
Publication Date(Web):
DOI:10.1002/jbm.a.33282
Abstract
Exogenous administration of growth factors has been identified as a potential therapeutic approach for healing wounds. A way to enhance the efficacy of growth factors would be to achieve spatiotemporal control over their delivery to desired sites for an extended period. In this study, we designed and prepared a kind of double-layered collagen membrane, a dense layer and a loose layer, which incorporated basic fibroblast growth factor (bFGF)-loaded chitosan-heparin nanoparticles. The nanoparticles were prepared by polyelectrolyte gelation process and then were sandwiched between the two layers of collagen membrane. The release of model protein human serum albumin (HSA) from the double-layered membrane was tracked by radio-label assay, and the bioactivity of the growth factor on fibroblast cell (L929) was evaluated by MTT assay. The release of protein displayed a spatiotemporal control model and its release in undesired direction was lessened. The bFGF maintained the bioactivities after release from the membranes. Moreover, different release amounts of bFGF from the different layers of the membrane induced significant difference in cell proliferation when the cells were seeded on the different layers of membrane in vitro. This kind of double-layered collagen membrane could have potential applications in the field of tissue repair due to the spatiotemporal control over growth factor delivery, the mild fabrication conditions, and the simple processes. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Co-reporter:Xi Zhou, Yanfeng Shi, Lei Ren, Shixiong Bao, Yu Han, Shichao Wu, Honggang Zhang, Lubin Zhong, Qiqing Zhang
Journal of Solid State Chemistry 2012 Volume 196() pp:138-144
Publication Date(Web):December 2012
DOI:10.1016/j.jssc.2012.05.025
Iron oxide nanocrystals (NCs) with a series of well-controlled morphologies (octahedron, rod, wire, cube and plate) and compositions (Fe3O4 and α-Fe2O3) were synthesized via a facile hydrothermal process. The morphological and compositional control of various iron oxide NCs was based on the regulations of precursor thermolysis kinetics and surfactants. The obtained samples were characterized by XRD, SEM, TEM, SQUID and cytotoxicity test. These as-prepared iron oxide NCs showed excellent magnetic properties and good biocompatibility, paving the way for their high-efficiency bio-separation and bio-detection applications.Graphical AbstractSchematic illustration for the formation of iron oxide NCs (Fe3O4 and α-Fe2O3) with different controlled morphologies and compositions.Highlights► Iron oxide NCs with a series of well-controlled morphologies (octahedron, rod, wire, cube, and plate) and compositions (Fe3O4 and α-Fe2O3) were synthesized via a facile hydrothermal method. ► The mechanism of the morphological and compositional control process is directly related to precursor thermolysis kinetics and surfactants. ► These iron oxide NCs exhibited excellent magnetic response and good biocompatibility, which should have great applications in the cell separation and biodetection.
Co-reporter:Xi-Ming Pu;Zhen-Zhen Sun;Zhen-Qing Hou;Yun Yang;Qing-Qing Yao;Qi-Qing Zhang
Journal of Biomedical Materials Research Part B: Applied Biomaterials 2012 Volume 100B( Issue 5) pp:1179-1189
Publication Date(Web):
DOI:10.1002/jbm.b.31961
Abstract
A composite rod for fracture fixation using chitosan (CHI)/hydroxylapatite (HA) was prepared by means of in situ precipitation, which had a layer-by-layer structure, good mechanical properties, and cell compatibilities. The CHI/HA composite rods were precipitated from the chitosan solution with calcium and phosphorus precursors, followed by treatment with a tripolyphosphate–trisodium phosphate solution (pH >13) to crosslink the CHI and to hydrolyze the calcium phosphates to nanocrystalline HA. The results of FTIR, XRD, and TEM measurements confirmed that HA had been formed within the CHI matrix. The effects of the CHI/HA ratios (20/0, 20/1, 20/2, 20/4, and 20/5, w/w) on the mechanical properties were investigated. At the CHI/HA ratio of 20/4 (w/w), the bending strength and modulus of the rods were 133 MPa and 6.8 GPa, respectively. Pre-osteoblast MC3T3-E1 cells were cultured in an extract of the CHI/HA rods (20/4, w/w) to study the cell compatibilities of the composite. The observations indicated that the CHI/HA composite could promote the growth of MC3T3-E1 cells better than the composite without HA (p < 0.05). Furthermore, the co-cultivation of the cells and the CHI/HA composite showed that cells fully spread on the surface of the composite with an obvious cytoskeleton organization, which also revealed that the CHI/HA composite had a good biocompatibility. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 1179–1189, 2012.
Co-reporter:Zhen Jiang, Lina Du, Xiyu Ding, Hui Xu, Yabiao Yu, Yanan Sun, Qiqing Zhang
Materials Science and Engineering: C 2012 Volume 32(Issue 5) pp:1280-1287
Publication Date(Web):1 July 2012
DOI:10.1016/j.msec.2012.04.007
The repeating decapeptides of the mussel adhesive protein (MAP) were considered as the basis for mussel adhesion in wet environment for it contains L-3, 4-dihydroxyphenylalanine (DOPA). However, DOPA residue in the Perna viridis foot protein-1 (Pvfp-1) do not exist in the repeating decapeptide sequence but present in the non-repeating region. Therefore, it is quite necessary to evaluate the adhesive capacity of the repeating and non-repeating regions of Pvfp-1. In this study, the sequence of eight repeating decapeptides (R-240) and the sequence of the non-repeating region (C-237) of Pvfp-1 was amplified and expressed, respectively. With adsorption, adhesion and coating analysis, it was found that the recombinant C-237 has comparable adhesion and coating ability compared with that of Cell-Tak™ (the positive control) and it was also much better than that of R-240, especially on the non-adhesive PTFE surface. Moreover, C-237 exhibited no cytotoxicity and showed better cell adhesion and spreading abilities than that of R-240 on both glass and PTFE surfaces. Therefore, the recombinant C-237 could be used as bioadhesive for medical purpose and be potentially used as an improver for bio-inert materials when applied in biomedical areas.Highlights► Recombinant R-240 and C-237 derived from Pvfp-1 were expressed and purified. ► Both proteins has good adhesion and coating abilities, especially the modified-C-237. ► Both proteins were non-toxic to cells. ► C-237 exhibited better cell-adhesion and spreading ability especially on PTFE surface. ► The adhesion mechanism for C-237 might be collagen-adhesion as well as DOPA-adhesion.
Co-reporter:Zhen Jiang, Yabiao Yu, Lina Du, Xiyu Ding, Hui Xu, Yanan Sun, Qiqing Zhang
Colloids and Surfaces B: Biointerfaces 2012 90() pp: 227-235
Publication Date(Web):
DOI:10.1016/j.colsurfb.2011.10.037
Co-reporter:Lubin Zhong, Xi Zhou, Shixiong Bao, Yanfeng Shi, Yan Wang, Shimin Hong, Yuancan Huang, Xiang Wang, Zhaoxiong Xie and Qiqing Zhang
Journal of Materials Chemistry A 2011 vol. 21(Issue 38) pp:14448-14455
Publication Date(Web):12 Jul 2011
DOI:10.1039/C1JM11193K
By taking advantage of the anisotropy of AuNRs, we design different bifunctional PEG molecules to selectively bind to either the end or side face and simultaneously protect other faces of individual AuNRs. In this way, we successfully achieve orientation-controllable assemblies of AuNRs into side-by-side (SS), end-to-end (EE) and end-to-side (ES) orientations based on the electrostatic interaction between carboxylic PEG and CTAB capping on AuNRs. Furthermore, we find that the different orientations of assembled motifs in these three types of AuNRs assemblies exhibited different near field coupling between the surface plasma of the neighboring AuNRs, leading to different surface-enhanced Raman signals. Undoubtedly, the current rational design of oriented assembly can be potentially useful for directing anisotropic nanoparticles into well-defined orientations, which provides a powerful route in designing families of novel nanodevices and nanomaterials with programmable electrical and optical properties.
Co-reporter:Youqun Lai, Yanyan Ma, Liping Sun, Jing Jia, Jian Weng, Nan Hu, Wei Yang, Qiqing Zhang
Electrochimica Acta 2011 Volume 56(Issue 9) pp:3153-3158
Publication Date(Web):30 March 2011
DOI:10.1016/j.electacta.2011.01.061
A highly selective electrochemical biosensor for the detection of Hg2+ in aqueous solution has been developed. This sensor is based on the strong and specific binding of Hg2+ by two DNA thymine bases (T–Hg2+–T). The hemin worked as a redox indicator to generate a readable electrochemical signal. Short oligonucleotide strands containing 5 thymine (T5) were used as probe. Thiolated T5 strands were self-assembled through Au–S bonding on gold electrode. In the presence of Hg2+, the specific coordination between Hg2+ and thymine bases resulted in more stable and porous arrangement of oligonucleotide strands, so hemin could be adsorbed on the surface of gold electrode and produced an electrochemical signal, which was monitored by differential pulse voltammetry (DPV). The DPV showed a linear correlation between the signal and the concentration of Hg2+ over the range 0–2 μM (R2 = 0.9983) with a detection limit of 50 nM. The length of probe DNA had no significant impact on the sensor performance. This electrochemical biosensor could be widely used for selective detection of Hg2+.Research highlights► A highly selective electrochemical biosensor for Hg2+ detection. ► Strong and specific binding of Hg2+ by two DNA thymine bases. ► Hemin worked as a redox indicator. ► Thiolated T5 strands were self-assembled on gold electrode. ► DPV showed a linear correlation between the signal and Hg2+ concentration.
Co-reporter:Mingmao Chen, Yan Liu, Wenzhi Yang, Xuemin Li, Lingrong Liu, Zhimin Zhou, Yinsong Wang, Ruifeng Li, Qiqing Zhang
Carbohydrate Polymers 2011 Volume 84(Issue 4) pp:1244-1251
Publication Date(Web):2 April 2011
DOI:10.1016/j.carbpol.2011.01.012
6-O-Cholesterol modified chitosan (O-CHCS) conjugates with succinyl linkages were synthesized through a protection-graft-deprotection method with phthaloylchitosan as an intermediate. O-CHCS conjugates were characterized by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H NMR), and the degrees of substitution (DS) of the cholesterol moiety determined by elemental analysis were 1.7%, 4.0% or 5.9%. O-CHCS self-assembled nanoparticles prepared by the dialysis method displayed the classic “core–shell” structures and their sizes were in the range of 100–240 nm. All-trans retinoic acid (ATRA), as a model drug, was physically entrapped inside O-CHCS self-assembled nanoparticles by the dialysis method. With increasing initial levels of the drug, the drug loading content increased, but the encapsulation efficiency and the particle size decreased. The release profiles in vitro demonstrated that ATRA showed slow sustained released over 72 h, which indicated that O-CHCS self-assembled nanoparticles had the potential to be used as a carrier for hydrophobic drugs.
Co-reporter:Cuilin Lin, Yifang Wang, Youqun Lai, Wei Yang, Fei Jiao, Honggang Zhang, Shefang Ye, Qiqing Zhang
Colloids and Surfaces B: Biointerfaces 2011 Volume 83(Issue 2) pp:367-375
Publication Date(Web):1 April 2011
DOI:10.1016/j.colsurfb.2010.12.011
Biodegradable poly(lactic-co-glycolic acid) (PLGA)/carboxyl-functionalized multi-walled carbon nanotube (c-MWCNT) nanocomposites were successfully prepared via solvent casting technique. Rat bone marrow-derived mesenchymal stem cells (MSCs) were employed to assess the biocompatibility of the nanocomposites in vitro. Scanning electron microscopy (SEM) observations revealed that c-MWCNTs gave a better dispersion than unmodified MWCNTs in the PLGA matrix. Surface properties were determined by means of static contact angle, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) analysis. The presence of c-MWCNTs increased the mechanical properties of the nanocomposites. Seven-week period in vitro degradation test showed the addition of c-MWCNTs accelerated the hydrolytic degradation of PLGA. In addition, SEM proved that the cells could adhere to and spread on films via cytoplasmic processes. Compared with control groups, MSCs cultured onto PLGA/c-MWCNT nanocomposites exhibited better adhesion and viability and also displayed significantly higher production levels of alkaline phosphatase (ALP) over 21 days culture. These results demonstrated that c-MWCNTs modified PLGA films were beneficial for promoting cell growth and inducing MSCs to differentiate into osteoblasts. This work presented here had potential applications in the development of 3-D scaffolds for bone tissue engineering.Graphical abstractResearch highlights▶ The carboxyl acid groups of acid-treated MWCNTs can form hydrogen bond with polymer matrix to enhance the dispersion of c-MWCNTs in the PLGA matrix. ▶ The incorporation of c-MWCNTs enhanced the mechanical strength of the nanocomposites due to the homogeneous distribution of c-MWCNTs in PLGA matrix. ▶ Addition of c-MWCNTs allowed a better hydrophilicity in the polymer matrix. ▶ The PLGA/c-MWCNT nanocomposites promoted the attachment, proliferation, and differentiation of rat MSCs, which would provide new insights in the PLGA/c-MWCNT nanocomposites for bone tissue engineering.
Co-reporter:Ruifeng Li;Xuemin Li;Lingrong Liu;Zhimin Zhou;Hongbo Tang
Macromolecular Rapid Communications 2010 Volume 31( Issue 22) pp:1981-1986
Publication Date(Web):
DOI:10.1002/marc.201000332
Co-reporter:Zhenqing Hou, Jing Han, Chuanming Zhan, Chunxiao Zhou, Quan Hu, Qiqing Zhang
Carbohydrate Polymers 2010 Volume 81(Issue 4) pp:765-768
Publication Date(Web):23 July 2010
DOI:10.1016/j.carbpol.2010.02.009
A new N-succinyl-chitosan derivative (NSC), which could be self-aggregated to form nanoparticles in distilled water, was synthesized by microwave irradiation and characterized by FTIR, element analysis, XRD and TEM. Hydroxycamptothecin (HCPT) used as a modal drug was successfully entrapped into the NSC nanoparticles. The size of NSC nanoparticles and HCPT-loaded NSC (NSCH) nanoparticles were around 30 and 200 nm, respectively. The drug entrapment efficiency of NSCH reached up to 68.5% and the release of HCPT was biphasic with an initial burst effect followed by a subsequent slower release. In vivo studies, the NSCH nanoparticles showed tumor targeting and significant suppression of tumor growth after s.c. injection (close to the tumor) to mice bearing S180 sarcoma tumor. A histopathological analysis of the tumor tissues indicated that NSCH had a lethal effect on the sarcoma cell. The results indicated that NSC nanoparticles had potential as a local sustained delivery system for hydrophobic antitumor drug.
Co-reporter:Hui-zhu Zhang, Fu-ping Gao, Ling-rong Liu, Xue-min Li, Zhi-min Zhou, Xin-du Yang, Qi-qing Zhang
Colloids and Surfaces B: Biointerfaces 2009 Volume 71(Issue 1) pp:19-26
Publication Date(Web):1 June 2009
DOI:10.1016/j.colsurfb.2008.12.039
Pullulan acetate (PA) was synthesized by the reaction of pullulan with acetic anhydride in the presence of pyridine. PA was characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR). A solvent diffusion method was employed in the current work to prepare PA nanoparticles. This technique had some advantages compared with other methods. The particle size increased from 185.7 nm to 423.0 nm with the degree of acetylation increasing from 2.71 to 3.0. Drug-loaded PA nanopaticles were prepared for controlled release of epirubicin (EPI). The drug entrapment and drug content increased with the degree substitution of PA increasing. EPI was released from the nanoparticles in a biphasic profile with a fast release rate in the first 10 h followed by a slow release in vitro. A higher cytotoxicity against KB cells was found for EPI-loaded PA nanoparticles in comparison with free EPI. Confocal laser scanning microscopy (CLSM) observations indicate that EPI-loaded nanoparticles were internalized and released in the cytoplasmic compartment.
Co-reporter:Zhimin Zhou, Jun Xu, Xiaoqing Liu, Xuemin Li, Siyue Li, Kun Yang, Xiaofeng Wang, Min Liu, Qiqing Zhang
Polymer 2009 50(15) pp: 3841-3850
Publication Date(Web):
DOI:10.1016/j.polymer.2009.05.047
Co-reporter:Zhenqing Hou;Heng Wei;Qian Wang;Qian Sun;Chunxiao Zhou
Nanoscale Research Letters 2009 Volume 4( Issue 7) pp:
Publication Date(Web):2009 July
DOI:10.1007/s11671-009-9312-z
The classical utilized double emulsion solvent diffusion technique for encapsulating water soluble Mitomycin C (MMC) in PLA nanoparticles suffers from low encapsulation efficiency because of the drug rapid partitioning to the external aqueous phase. In this paper, MMC loaded PLA nanoparticles were prepared by a new single emulsion solvent evaporation method, in which soybean phosphatidylcholine (SPC) was employed to improve the liposolubility of MMC by formation of MMC–SPC complex. Four main influential factors based on the results of a single-factor test, namely, PLA molecular weight, ratio of PLA to SPC (wt/wt) and MMC to SPC (wt/wt), volume ratio of oil phase to water phase, were evaluated using an orthogonal design with respect to drug entrapment efficiency. The drug release study was performed in pH 7.2 PBS at 37 °C with drug analysis using UV/vis spectrometer at 365 nm. MMC–PLA particles prepared by classical method were used as comparison. The formulated MMC–SPC–PLA nanoparticles under optimized condition are found to be relatively uniform in size (594 nm) with up to 94.8% of drug entrapment efficiency compared to 6.44 μm of PLA–MMC microparticles with 34.5% of drug entrapment efficiency. The release of MMC shows biphasic with an initial burst effect, followed by a cumulated drug release over 30 days is 50.17% for PLA–MMC–SPC nanoparticles, and 74.1% for PLA–MMC particles. The IR analysis of MMC–SPC complex shows that their high liposolubility may be attributed to some weak physical interaction between MMC and SPC during the formation of the complex. It is concluded that the new method is advantageous in terms of smaller size, lower size distribution, higher encapsulation yield, and longer sustained drug release in comparison to classical method.
Co-reporter:Liping Sun;Zhaowu Zhang;Shuang Wang;Jianfeng Zhang;Hui Li
Nanoscale Research Letters 2009 Volume 4( Issue 3) pp:
Publication Date(Web):2009 March
DOI:10.1007/s11671-008-9228-z
Gold nanoparticles (GNPs) are widely used to detect DNA. We studied the effect of pH on the assembly/disassembly of single-stranded DNA functionalized GNPs. Based on the different binding affinities of DNA to GNPs, we present a simple and fast way that uses HCl to drive the assembly of GNPs for detection of DNA sequences with single nucleotide differences. The assembly is reversible and can be switched by changing the solution pH. No covalent modification of DNA or GNP surface is needed. Oligonucleotide derived from human p53 gene with one-base substitution can be distinguished by a color change of the GNPs solution or a significant difference of the maximum absorption wavelength (λmax), compared with wildtype sequences. This method enables detection of 10 picomole quantities of target DNA.
Co-reporter:Hongli Chen, Wenzhi Yang, Han Chen, Lingrong Liu, Fuping Gao, Xindu Yang, Qian Jiang, Qiqing Zhang, Yinsong Wang
Colloids and Surfaces B: Biointerfaces 2009 Volume 73(Issue 2) pp:212-218
Publication Date(Web):15 October 2009
DOI:10.1016/j.colsurfb.2009.05.020
The purpose of this research was to develop polylactic-co-glycolic acid (PLGA) nanospheres surface modified with chitosan (CS). Mitoxantrone- (MTO-) loaded PLGA nanospheres were prepared by a solvent evaporation technique. The PLGA nanospheres surface was modified with CS by two strategies (adsorption and covalent binding). PLGA nanospheres of 248.4 ± 21.0 nm in diameter characterized by the laser light scattering technique, scanning electron microscopy (SEM) are spherical and its drug encapsulation efficiency is 84.1 ± 3.4%. Zeta potential of unmodified nanospheres was measured to be negative −21.21 ± 2.13 mV. The positive zeta potential of modified nanospheres reveals the presence of CS on the surface of the modified nanospheres. Modified nanospheres were characterized for surface chemistry by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR). FT-IR spectra exhibited peaks at 3420 cm−1 and 1570 cm−1, XPS spectra shows the N 1s (atomic orbital 1s of nitrogen) region of the surface of the nanospheres, corresponding to the primary amide of CS. In vitro drug release demonstrated that CS-modified nanospheres have many advantages such as prolonged drug release property and decreased the burst release over the unmodified nanospheres, and the modified nanospheres by covalent binding method could achieve the release kinetics of a relatively constant release. These data demonstrate high potential of CS-modified PLGA nanospheres for the anticancer drug carrier.
Co-reporter:Fu-Ping Gao, Hui-Zhu Zhang, Ling-Rong Liu, Yin-Song Wang, Qian Jiang, Xin-Du Yang, Qi-Qing Zhang
Carbohydrate Polymers 2008 Volume 71(Issue 4) pp:606-613
Publication Date(Web):7 March 2008
DOI:10.1016/j.carbpol.2007.07.008
Various deoxycholic acid (DOCA)-modified-carboxymethylated (CM)-curdlan (DCMC) were synthesized and characterized by FTIR, 1H NMR and XRD. The degree of DOCA substitution (DS), as spectrophotometrically determined, was 2.1, 3.2, 4.1, or 6.3 DOCA groups per hundred sugar residues of CM-curdlan. The physicochemical properties of the self-assembled nanoparticals in aqueous media were investigated using 1H NMR, dynamic light scattering, zeta potential, transmission electron microscopy (TEM) and fluorescence spectroscopy. DCMC conjugates provided monodispersed self-assembled nanoparticles in water, with mean diameter decreasing from 192 to 347 nm with DOCA DS increasing. Moreover, the mean diameter also increased with decreasing pH in PBS. Zeta potential of DCMC self-assembled nanoparticles exhibited near −60 mV in distilled water and −26 to −36 mV in PBS, indicating these nanoparticles were covered with negatively charged CM-curdlan shells. The critical aggregation concentration (cac) of the DCMC were dependent on the degree of substitution (DS) of DOCA and were slightly lower in PBS than in distilled water. The TEM images demonstrated that these self-assembled nanoparticles were of spherical shape.
Co-reporter:Xindu Yang, Qiqing Zhang, Yinsong Wang, Han Chen, Huizhu Zhang, Fuping Gao, Lingrong Liu
Colloids and Surfaces B: Biointerfaces 2008 Volume 61(Issue 2) pp:125-131
Publication Date(Web):15 February 2008
DOI:10.1016/j.colsurfb.2007.07.012
Methoxy poly(ethylene glycol)-grafted-chitosan (mPEG-g-CS) conjugates were synthesized by formaldehyde linking method and characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H-NMR). The degree of substitution (DS) of methoxy poly (ethylene glycol) (mPEG) in the mPEG-g-CS molecules determined by 1H-NMR ranged from 19% to 42%. The critical aggregation concentration (CAC) was determined by fluorescence spectroscopy using pyrene as fluorescence probe and its value was 0.07 mg/mL in water. mPEG-g-CS formed monodisperse self-aggregated nanoparticles with a roughly spherical shape and a mean diameter of 261.9 nm were prepared by the dialysis method. mPEG-g-CS self-aggregated nanoparticles were used as carriers of poorly water-soluble anticancer drug methotrexate (MTX). MTX was physically entrapped inside mPEG-g-CS self-aggregated nanoparticles by dialysis method and the characteristics of MTX-loaded mPEG-g-CS self-aggregated nanoparticles were analyzed using dynamic laser light scattering (DLLS), transmission electron microscopy (TEM). Moreover, in vitro release behavior of MTX was also investigated and the results showed that MTX was continuously released more than 50% in 48 h.
Co-reporter:Wang Yinsong, Liu Lingrong, Weng Jian, Qiqing Zhang
Carbohydrate Polymers 2007 Volume 69(Issue 3) pp:597-606
Publication Date(Web):25 June 2007
DOI:10.1016/j.carbpol.2007.01.016
A series of cholesterol-modified O-carboxymethyl chitosan (CCMC) conjugates with different degrees of substitution (DS) of cholesterol moiety were synthesized by the succinyl linkages and characterized by Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR) and elemental analysis. CCMC conjugates were amphiphilic in nature and their self-aggregation behavior in aqueous media was evaluated by the fluorescence probe technique. CCMC self-aggregated nanoparticles were prepared by probe sonication in water and analyzed by dynamic laser light-scattering (DLLS), zeta potential and transmission electron microscopy (TEM) technologies. These novel nanoparticles were almost spherical in shape, and their size, ranging from 234.9 to 100.1 nm, could be controlled by DS of cholesterol moiety. The zeta potentials of CCMC self-aggregated nanoparticles were negative, and the absolute values decreased with increasing DS of the cholesterol moiety. This study also compared the morphology and the stability of self-aggregated nanoparticles between CCMC and cholesterol-modified chitosan (CHCS). The results showed that the negatively charged carboxymethyl groups are advantageous for the formation of well-shaped and stable self-aggregated nanoparticles.
Co-reporter:Yin-Song Wang, Ling-Rong Liu, Qian Jiang, Qi-Qing Zhang
European Polymer Journal 2007 Volume 43(Issue 1) pp:43-51
Publication Date(Web):January 2007
DOI:10.1016/j.eurpolymj.2006.09.007
Cholesterol-modified chitosan conjugate with succinyl linkages (CHCS) was synthesized and characterized by fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR). The degree of substitution (DS) of cholesterol moiety determined by elemental analysis was 7.3%. The self-aggregation behavior of CHCS was evaluated by the fluorescence probe technique and the critical aggregation concentration (CAC) was 1.16 × 10−2 mg mL−1 in 0.1 M acetic acid solution. CHCS formed monodisperse self-aggregated nanoparticles with a roughly spherical shape and a mean diameter of 417.2 nm by probe sonication in aqueous media. Epirubicin (EPB), as a model anticancer drug, was physically entrapped inside CHCS self-aggregated nanoparticles by the remote loading method and the characteristics of EPB-loaded CHCS self-aggregated nanoparticles were analyzed using dynamic laser light scattering (DLLS), transmission electron microscopy (TEM) and fluorescence spectroscopy. EPB-loaded CHCS self-aggregated nanoparticles were almost spherical in shape and their size increased from 338.2 to 472.9 nm with the EPB-loading content increasing from 7.97% to 14.0%. The release behavior of EPB from CHCS self-aggregated nanoparticles was studied in vitro by dialysis method. The results showed that EPB release rate decreased with the pH increase of the release media. In phosphate buffered saline (PBS, pH 7.4), the EPB release was very slow and the total release amount was about 24.9% in 48 h.
Co-reporter:Guan Man;Ren Lei;Wu Ting;Sun Li-Ping;Li Ling-Rong;Zhang Qi-Qing
Journal of Applied Polymer Science 2007 Volume 105(Issue 3) pp:1679-1686
Publication Date(Web):25 APR 2007
DOI:10.1002/app.26291
Cultured skin substitutes have provided a new approach for the closure of wounds, but these avascular grafts are subject to microbial destruction that may lead to tissue infection. To minimize wound infection, HN-300 (a new inorganic antimicrobial particle) was incorporated into the collagen–chitosan wound dressing. Antimicrobial, cytotoxicity, release rate, swelling, and mechanical properties of this material were assessed. The antimicrobial property was enhanced with the increasing dosage of HN-300. When the concentration of HN-300 was more than 5%, the films showed sustained and stable antimicrobial property within 144 h. When the concentration of HN-300 was less than 7.5%, the wound dressings were noncytotoxic and compatible for L929 fibroblasts. So 5% HN-300 in antimicrobial films was suitable and the concentration also could improve the mechanical properties of the collagen–chitosan wound dressings. After treatment with 5% glycerol, the film's stability was enhanced and silver ions were protected at the same time. Hence, collagen/chitosan/HN-300 films are of great potential in application as wound dressing in future, because of their good biosafety and physical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Co-reporter:Fengxia Liu;Lingrong Liu;Xuemin Li
Journal of Materials Science: Materials in Medicine 2007 Volume 18( Issue 11) pp:2215-2224
Publication Date(Web):2007 November
DOI:10.1007/s10856-007-3228-x
Chitosan (CHS)−hyaluronate (HA) double-walled microspheres were prepared by emulsification-coacervation method. Tripolyphosphate (TPP) acted as ion crosslinker. The effects of oil/water volume ratio, surfactant, solution pH, TPP concentration, HA concentration, and emulsification time on microspheres fabrication and morphology were examined by Zeta (ζ) potential, Scanning electron microscopy (SEM) and Fourier-transform infrared spectrometry (FT-IR). It was found that TPP concentration, solution pH, surfactant and emulsification time were crucial factors for microspheres fabrication. Spherical microspheres with smooth surface were formed when TPP concentration was 8% or higher. The optimal pH for microspheres formation ranged from 6.0 to 7.0. As for surfactant, the microspheres obtained when span80 was applied alone were shapelier compared with those obtained when both span80 and tween80 were applied. With insufficient emulsification time, vacuous microcapsules, but not compact microspheres were formed. In addition, oil/water volume ratio and HA concentration also affected the microspheres morphology, but less importantly.
Co-reporter:J. Weng;J. Xue;J. Wang;J. Ye;H. Cui;F. Sheu;Q. Zhang
Advanced Functional Materials 2005 Volume 15(Issue 4) pp:
Publication Date(Web):23 MAR 2005
DOI:10.1002/adfm.200400049
Gold clusters have been electrodeposited on a boron-doped diamond (BDD) electrode by scanning the potential from 0.7 V to 0.0 V (vs. 3 M KCl-Ag/AgCl reference) in a solution of 0.5 mM KAuCl4 and 1.0 M KCl. The cluster-modified diamond (Au/BDD) electrode has been used to investigate the oxidative properties of dopamine (DA) and ascorbate (AA). The modified diamond electrode shows a higher activity for DA oxidation than AA; the oxidation potential of DA shifted to a less-positive potential (0.11 V) than that of AA, which oxidized at 0.26 V, and DA possesses a much higher peak current than that of AA. The reversibility of the electrode reaction with DA is significantly improved at the Au/BDD electrode, which results in a large increase in the square-wave voltammetric peak current, with a detection limit of 0.1 μM in the presence of a large excess of AA. The Au/BDD electrode shows excellent sensitivity and good selectivity for DA detection. A self-assembled monolayer (SAM) of mercaptoacetic acid on the Au clusters was used to provide an antifouling effect as the negative CO2– groups repulse negative ascorbate and attract positive dopamine in pH 7.4 buffer. After pre-absorption, the SAM/Au/BDD electrode could detect 1.0 nM DA in a linear range from 10 nM to 10 μM in the presence of 10–4 M AA.
Co-reporter:Jian Weng
Journal of Polymer Science Part A: Polymer Chemistry 2005 Volume 43(Issue 22) pp:5414-5428
Publication Date(Web):29 SEP 2005
DOI:10.1002/pola.20960
We synthesized a series of cyclens substituted with mixed stilbene and poly(ethylene glycol) dendritic arms. All dendrimers terminated with different peripheral groups had good solubility in common organic solvents, and dendrimers terminated with CO2H groups (CO2H-dendrimers) were also soluble in alkaline solutions. The nickel coordination properties of these dendrimers were investigated in organic solvents. Dendrimers terminated with CN groups (CN-dendrimers) and the second-generation CO2H-dendrimer [(CO2H)8L2] could produce pentacoordinated nickel complexes; the third-generation CO2H-dendrimer [(CO2H)16L3] could form tetra- and pentacoordinated nickel complexes, and the nickel complex of the fourth-generation CO2H-dendrimer [(CO2H)32L4] could not be obtained. This result was due to the fact that the globular surface of (CO2H)16L3 formed a hydrogen-bond network that selectively penetrated cations and inhibited the access of anions to the core. The formation of the hydrogen-bond network was confirmed by Fourier transform infrared, 1H NMR, and fluorescence data. The CN-dendrimers could not form hydrogen bonds on the surface, and the first- and second-generation CO2H-dendrimers could not form intramolecular hydrogen-bond networks. Therefore, they had no selectivity for positive nickel ions and negative chloride ions. (CO2H)32L4 could not produce a nickel complex because it had a crammed backbone structure that could not penetrate nickel and chloride ions. Therefore, it was possible to control the ion access of cations and anions with the hydrogen-bond network of (CO2H)16L3. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5414–5428, 2005
Co-reporter:Lubin Zhong, Xi Zhou, Shixiong Bao, Yanfeng Shi, Yan Wang, Shimin Hong, Yuancan Huang, Xiang Wang, Zhaoxiong Xie and Qiqing Zhang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 38) pp:NaN14455-14455
Publication Date(Web):2011/07/12
DOI:10.1039/C1JM11193K
By taking advantage of the anisotropy of AuNRs, we design different bifunctional PEG molecules to selectively bind to either the end or side face and simultaneously protect other faces of individual AuNRs. In this way, we successfully achieve orientation-controllable assemblies of AuNRs into side-by-side (SS), end-to-end (EE) and end-to-side (ES) orientations based on the electrostatic interaction between carboxylic PEG and CTAB capping on AuNRs. Furthermore, we find that the different orientations of assembled motifs in these three types of AuNRs assemblies exhibited different near field coupling between the surface plasma of the neighboring AuNRs, leading to different surface-enhanced Raman signals. Undoubtedly, the current rational design of oriented assembly can be potentially useful for directing anisotropic nanoparticles into well-defined orientations, which provides a powerful route in designing families of novel nanodevices and nanomaterials with programmable electrical and optical properties.
