-
[show abstract]
[hide abstract]
ABSTRACT: A series of hexylamine modified polysuccinimide (PSI – HA) copolymers were synthesized by aminolysis of polysuccinimide (PSI) with hexylamine. FTIR and 1 H NMR measurements confirmed the structure of the copolymers and the substitution degree of the N-hexyl aspartamide units ranged from 7 to 92 mol%. Stable nanoparticles formed when the DMF solution of PSI– HA copolymers was dropped into excess water, and the particle size reduced as increasing the substitution degree. 1 H NMR analysis indicated that hexyl chain and succinimide units interacted to form the hydrophobic core, while, the nanoparticles were stabilized by the amide groups which formed hydrogen bonds with the surrounding water molecules. The nanoparticles became more compact at higher temperature due to the break of hydrogen bonds between amide groups and water molecules. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) results showed that the nanoparticles were nearly spherical. Larger nanoparticles formed when the dispersion concentration increased from 0.1% to 1.0% according to the DLS and steady-state fluorescence measurements. After the nanoparticles formed in water, a sequential dilution can't influence the particles size of the nanoparticles any longer.
Online) Part A—Pure and Applied Chemistry. ; 40:1060-1325.
-
[show abstract]
[hide abstract]
ABSTRACT: A novel controlled drug delivery system (CDDS) based on fluorescent mesoporous silica nanoparticles (FMSN) covalently linked with paclitaxel (PTX) via disulfide linker was designed and characterized. A PTX prodrug based on disulfide linker was synthesized and its drug delivery mechanism was determined through HPLC characterization. Utilizing the carboxyl group of the prodrug, PTX was covalently conjugated to the surface of amino-functionalized FMSN, with a disulfide linker as spacer to bridge PTX and FMSN, and the loading content of PTX reached as high as 13% by weight. The most important feature of this nanoscale CDDS is that the PTX prodrug modules conjugated with FMSN can be activated to its cytotoxic form inside the tumor cells upon internalization and in situ drug release. To prove the efficacy of this CDDS, glutathione-mediated intracellular drug delivery was investigated against HeLa cell line, and the results indicated that our CDDS showed higher cellular proliferation inhibition against glutathione monoester pretreated cells than that of the untreated ones and the cytotoxicity increased with increasing intracellular glutathione concentration. The result indicates that the CDDS can release PTX molecules to kill cancer cells and the release behavior is GSH-dependent. Furthermore, the in vitro evaluation revealed that the FMSN-PTX conjugate could be effectively taken up by HeLa cells. All the results suggest that this redox-responsive CDDS is potentially useful as a drug delivery system that can reduce toxic and side effects of anticancer drugs.
Langmuir 12/2012; · 4.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A novel controlled drug delivery system based on copolymer covalently linked paclitaxel via a disulfide bond was constructed. Copolymer with poly(ethylene glycol) (PEG) side chains and carboxyl groups on the backbone was prepared by radical copolymerization of tert-butyl acrylate and poly(ethylene glycol) methyl ether acrylate, followed by selectively hydrolyzing tert-butyl groups to carboxyl groups. Utilizing the carboxyl group as an active reaction site, paclitaxel, a well-known chemotherapeutic drug, could be covalently linked to the backbone of a copolymer via a disulfide bond, and the loading content of paclitaxel could reach up to 32 wt %. In aqueous solution, this drug-loaded copolymer could self-assemble into a spherical micelle, with the hydrophobic drug as the core and hydrophilic PEG as the shell. The mean diameter of the micelles evaluated by transmission electron microscopy (TEM) and dynamic light scattering (DLS) was approximately 60 nm. The in vitro cytotoxicity experiments showed that the copolymer was biocompatible and suitable to use as a drug carrier. After covalently loading the drug, the copolymer showed apparent cytotoxicity to OS-RC-2 cells (kidney tumor cells) and low cytotoxicity to macrophage cells (human normal cells), indicating that the disulfide bond was stable in human normal cells, but would be broken in tumor cells. This selective bond scission behavior is potentially favorable for reducing the toxic and side effects of chemotherapeutic drugs.
The Journal of Physical Chemistry B 07/2012; 116(30):9231-7. · 3.70 Impact Factor
-
Journal of Polymer Science Part A Polymer Chemistry 01/2012; 50:4451-4458. · 3.92 Impact Factor
-
Journal of Polymer Science Part A Polymer Chemistry 07/2011; 49(18):4055 - 4064. · 3.92 Impact Factor
-
Journal of Polymer Science Part A Polymer Chemistry 05/2011; 49(15):3328 - 3337. · 3.92 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Poly(acrylic acid) grafted mesoporous silica nanoparticles (PAA-MSNs) were prepared by a facile graft-onto strategy, i.e., the amidation between PAA homopolymer and amino group functionalized MSNs. The resultant PAA-MSNs were uniform spherical nanoparticles with a mean diameter of approximately 150 nm, and the graft amount of PAA evaluated by thermogravimetric analysis (TGA) was about 12 wt %. Due to the covalent graft of hydrophilic and pH-responsive PAA, the PAA-MSNs could be well dispersed in aqueous solution, which is favorable to be utilized as drug carriers to construct a pH-responsive controlled drug delivery system. N2 adsorption–desorption isotherm results demonstrated that doxorubicin hydrochloride (DOX), a well-known anticancer drug, could be effectively loaded into the channels of PAA-MSNs through the electrostatic interaction. The loading content and the entrapment efficiency of DOX could reach up to 48% and 95%, respectively. The drug release rate of DOX@PAA-MSN was pH dependent and increased with the decrease of pH. The in vitro cytotoxicity test indicated that PAA-MSNs were highly biocompatible and suitable to use as drug carriers. The drug-loaded DOX@PAA-MSNs were distinctly cytotoxic to HeLa cells, due to the sustained release of drug, and showed higher clinical effects than free DOX. These results imply that the PAA-MSNs are promising platforms to construct pH-responsive controlled drug delivery systems for cancer therapy.
05/2011;
-
[show abstract]
[hide abstract]
ABSTRACT: Strategies using carbon-based nanomaterials as carriers for delivering chemotherapeutic drugs to cancers have been described well. Here a novel magnetic lymphatic-targeting drug-delivery system, based on functionalised carbon nanotubes (fCNTs), is presented with the aim of improving the outcome of cancer with lymph node involvement. The potential therapeutic effect of gemcitabine (GEM) loading magnetic multiwalled carbon nanotubes (mMWNTs) was compared with that of GEM loading magnetic-activated carbon particles (mACs) in vitro and in vivo. mMWNTs-GEM and mACs-GEM both had high anti-tumour activity in vitro similar to free drug. Subcutaneous administration of GEM loading magnetic nanoparticles resulted in successful regression and inhibition of lymph node metastasis under the magnetic field, with mMWNTs-GEM superior to mACs-GEM, and more effectively in the high-dose versus low-dose groups. The successful application of intra-lymphatic delivery of chemotherapeutics using mMWNTs highlights the clinical potential of fCNTs for future cancer metastasis treatment with high efficacy and minimum side-effects.
European journal of cancer (Oxford, England: 1990) 04/2011; 47(12):1873-82. · 4.12 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A series of novel graft copolymers consisting of perfluorocyclobutyl aryl ether-based backbone and poly(methyl methacrylate) side chains were synthesized by the combination of thermal [2 pi + 2 pi] step-growth cycloaddition polymerization of aryl bistrifluorovinyl ether monomer and atom transfer radical polymerization (ATRP) of methyl methacrylate. A new aryl bistrifluorovinyl ether monomer, 2-methyl-1,4-bistrifluorovinyloxy-benzene, was first synthesized in two steps from commercially available reagents, and this monomer was homopolymerized in diphenyl ether to provide the corresponding perfluorocyclobutyl aryl ether-based homopolymer with methoxyl end groups. The fluoropolymer was then converted to ATRP macroinitiator by the monobromination of the pendant methyls with N-bromosuccinimide and benzoyl peroxide. The grafting-from strategy was finally used to obtain the novel poly(2-methyl-1,4-bistrifluorovinyloxybenzene)-g-poly(methyl methacrylate) graft copolymers with relatively narrow molecular weight di
Journal of Polymer Science Part a-Polymer Chemistry. 01/2011; 49(1):11-22.
-
[show abstract]
[hide abstract]
ABSTRACT: Graft copolymers with a large number of side chains chemically attached onto a linear backbone are endowed with unusual properties thanks to their confined and compact structures, including wormlike conformation, compact molecular dimensions and notable chain end effects. Growing attention has been paid to these interesting macromolecules due to their importance in understanding the correlation between architectures and properties, as well as their potential applications. To date, the synthesis and properties of graft copolymers in both solution and bulk have been extensively investigated, along with their applications. In this tutorial review, recent advances in synthetic approaches towards the construction of well-defined graft copolymers are discussed in detail and applications of these interesting macromolecules are highlighted by selected examples.
Chemical Society Reviews 11/2010; 40(3):1282-95. · 28.76 Impact Factor
-
Journal of Polymer Science Part A Polymer Chemistry 05/2010; 48(12):2622 - 2630. · 3.92 Impact Factor
-
Journal of Polymer Science Part A Polymer Chemistry 04/2010; 48(10):2084 - 2097. · 3.92 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A series of well-defined double hydrophilic graft copolymers, consisting of poly(N-isopropylacrylamide)-b-poly-(ethyl acrylate) backbone and poly(2-vinylpyridine) side chains, were synthesized by successive single-electron-transfer living radical polymerization (SET-LRP) and atom transfer radical polymerization (ATRP). The backbone was prepared by sequential SET-LRP of N-isopropylacrylamide and 2-hydroxyethyl acrylate at 25 degrees C using CuCl/tris(2-(dimethylamino)ethyl)amine as the catalytic system. The obtained diblock copolymer was transformed into the macroinitiator by reacting with 2-chloropropionyl chloride. Next, grafting-from strategy was used for the synthesis of poly(N-isopropylacrylamide)-b-[poly(ethyl acrylate)-g-poly (2-vinylpyridine)] double hydrophilic graft copolymer. ATRP of 2-vinylpyridine was initiated by the macroinitiator at 25 degrees C using CuCl/hexamethyldiethylenetriamine as the catalytic system. The synthesis of both the backbone and the side chains are controllable. Thermo- a
Journal of Polymer Science Part a-Polymer Chemistry. 01/2010; 48(1):15-23.
-
[show abstract]
[hide abstract]
ABSTRACT: A series of well-defined binary hydrophilic-fluorophilic diblock copolymers were synthesized by successive atom transfer radical polymerization (ATRP) of methoxylmethyl acrylate (MOMA) and 4-(4'-p-tolyloxyperfluorocyclobutoxy)benzyl methacrylate (TPFCBBMA) followed by the acidic selective hydrolysis of the hydrophobic poly(methoxymethyl acrylate) (PMOMA) segment into the hydrophilic poly (acrylic acid) (PAA) segment. ATRP of MOMA was initiated by 2-MBP at 50 degrees C in bulk to give two different PMOMA homopolymers with narrow molecular weight distributions (M(w)/M(n) <= 1.15). PMOMA-b-PTPFCBBMA well-defined diblock copolymers were synthesized by ATRP of TPFCBBMA at 90 degrees C in anisole using Br-end-functionalized PMOMA homopolymer as macroinitiator and CuBr/PMDETA as catalytic system. The final PAA-b-PTPFCBBMA amphiphilic diblock copolymers were obtained via the selective hydrolysis of PMOMA block in dilute HCl without affecting PTPFCBBMA block. The critical micelle concentrations (cmc) of PAA-b-PTPF
Polymer. 01/2010; 51(8):1752-1760.
-
[show abstract]
[hide abstract]
ABSTRACT: A series of novel perfluorocyclobutyl aryl ether-containing graft copolymers with polystyrene side chains were synthesized by the combination of thermal step-growth [2 pi + 2 pi] cycloaddition polymerization of aryl bistrifluorovinyl ether monomer and atom transfer radical polymerization (ATRP) of styrene. We first synthesized a new aryl bistrifluorovinyl ether monomer of 2-methyl-1,4-bistrifluorovinyloxybenzene in two steps using commercially available 2-methylhydroquinone as starting material and the corresponding perfluorocyclobutyl aryl ether-based homopolymer with methoxyl end groups was prepared through the homopolymerization of this monomer in diphenyl ether. Next, the pendant methyls of this fluoropolymer were mono-brominated by N-bromosuccinimide and benzoyl peroxide so as to be converted to ATRP initiation groups. The targeted poly(2-methy1-1,4-bistrifluorovinyloxybenzene)-g-poly-styrene with relatively narrow molecular weight distributions (M(w)/M(n) <= 1.38) was obtained by the combination of
Polymer. 01/2010; 51(22):5198-5206.
-
Journal of Polymer Science Part A Polymer Chemistry 12/2009; 48(3):647 - 655. · 3.92 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Hydrophilic multi-walled carbon nanotubes decorated with magnetite nanoparticles were readily taken up into lymph vessels and delivered gemcitabine to lymph nodes with high efficiency under the guidance of a magnetic field.
Chemical Communications 09/2009; · 6.17 Impact Factor
-
Journal of Polymer Science Part A Polymer Chemistry 05/2009; 47(12):3142 - 3153. · 3.92 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Submicron-size Fe(3)O(4)@silica core/shell microspheres were prepared by sol-gel method. Through coating inert silica shell and adjusting the thickness, the dispersibility of magnetic microspheres in water was greatly improved. The resultant Fe(3)O(4)@silica microspheres with controllable saturation magnetization between 34.3 emu/g and 47.3 emu/g were superparamagnetic. All as-prepared magnetic composite microspheres possessed fleetly magnetic responsivity. The PAA-modified Fe(3)O(4)@silica microspheres were used for selective adsorption and separation of lysozyme, and the experimental results showed that the maximum binding capacity is about 127 mg/g. After surface modification of Fe(3)O(4)@silica with polyacrylic acid (PAA) flexible chains, the binding capacity of Fe(3)O(4)@silica-g-PAA microspheres for lysozyme were 22 times as much as that of pure Fe(3)O(4)@silica microspheres at the same pH condition.
Journal of Colloid and Interface Science 05/2009; 336(2):526-32. · 3.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Magnetite−silica nanocomposites were controllably synthesized by a sol−gel approach, using electrostatically stabilized magnetite nanoparticles as seeds. By virtue of the complexation occurring between the iron ions on the magnetic nanoparticles and the citrate groups, highly stable magnetic fluid (MF) containing well-dispersed magnetite nanoparticles can be obtained. Controlling the surface modification degree, magnetite nanoparticles charged with different amount of citrate groups can be obtained for coating process with silica through the seeded sol−gel approach, and magnetite−silica nanocomposites with morphologies including irregular clusters, core−shell particles can be synthesized. Moreover, silica−magnetite particles with well-defined core−shell structure and controllable silica thickness can be synthesized.
04/2009;
