首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
This study explored the feasibility of using surface-modified nanoparticulate drug delivery system to enhance the transepithelial transport of antitumor drugs. An antitumor drug, 10-hydroxycamptothecin, was encapsulated into nanoparticles made of biodegradable poly(caprolactone-co-lactide)-PEG-poly(caprolactone-co-lactide) by a novel two-step nano-precipitation method. The obtained nanoparticles had a drug loading content of 10.4% and a size of 256.3 nm, exhibiting a steady and sustained in vitro release profile. By incubation in chitosan containing medium, the drug-loaded nanoparticles could be subsequently surface-modified with chitosan. The surface modification was monitored by dynamic light scattering method, zeta potential observation, and transmission electron microscopy, and its degree could be easily adjusted by varying the concentration of chitosan in the incubation medium. Caco-2 cell monolayer was used as an in vitro model to evaluate the intestinal 10-hydroxycamptothecin absorption. The absorptive transport of 10-hydroxycamptothecin could be improved to some extent by drug loaded nanoparticles and could be further enhanced in the case of surface-modified nanoparticles, suggesting that chitosan surface-modified nanoparticles may be a promising oral delivery system for antitumor drugs.  相似文献   

2.
Novel drug delivery system by surface modified magnetic nanoparticles   总被引:2,自引:0,他引:2  
In the recent progress of gene and cell therapy, novel drug delivery system (DDS) has been required for efficient delivery of small molecules/drugs and also the safety for clinical usage. We have already developed the unique transfection technique by preparing magnetic vector and using permanent magnet. This technique can improve the transfection efficiency. In this study, we directly associated plasmid DNA with magnetic nanoparticles, which can potentially enhance their transfection efficiency by magnetic force. Magnetic nanoparticle, such as magnetite, its average size of 18.7 nm, can be navigated by magnetic force and is basically consisted with oxidized Fe that is commonly used as the supplement drug for anemia. The magnetite particles coated with protamine sulfate, which gives a cationic surface charge onto the magnetite particle, significantly enhanced the transfection efficiency in vitro cell culture system. The magnetite particles coated with protamine sulfate also easily associated with cell surface, leading to high magnetic seeding percentage. From these results, it was found that the size and surface chemistry of magnetic particles would be tailored to meet specific demands on physical and biological characteristics accordingly. Overall, magnetic nanoparticles with different surface modification enhance the association with plasmid DNA and cell surface as well as HVJ-E, which potentially help to improve the drug delivery system.  相似文献   

3.
Many therapeutic drugs are excluded from entering the brain due to their lack of transport through the blood–brain barrier (BBB). The development of new strategies for enhancing drug delivery to the brain is of great importance in diagnostics and therapeutics of central nervous diseases. To overcome this problem, a viral fusion peptide (gH625) derived from the glycoprotein gH of Herpes simplex virus type 1 is developed, which possesses several advantages including high cell translocation potency, absence of toxicity of the peptide itself, and the feasibility as an efficient carrier for delivering therapeutics. Therefore, it is hypothesized that brain delivery of nanoparticles conjugated with gH625 should be efficiently enhanced. The surface of fluorescent aminated polystyrene nanoparticles (NPs) is functionalized with gH625 via a covalent binding procedure, and the NP uptake mechanism and permeation across in vitro BBB models are studied. At early incubation times, the uptake of NPs with gH625 by brain endothelial cells is greater than that of the NPs without the peptide, and their intracellular motion is mainly characterized by a random walk behavior. Most importantly, gH625 peptide decreases NP intracellular accumulation as large aggregates and enhances the NP BBB crossing. In summary, these results establish that surface functionalization with gH625 may change NP fate by providing a good strategy for the design of promising carriers to deliver drugs across the BBB for the treatment of brain diseases.  相似文献   

4.
Two polymers chitosan and poly(lactide-co-glycolide) copolymer (PLGA) were investigated to develop nanoparticles (NPs) for delivery of protein drug substance into tumour cells. Cystatin was selected as a model protein drug due to its high potential to inhibit cysteine proteases, known to trigger the invasive process. Ionotropic gelation of chitosan with tripolyposphate and precipitation of PLGA polymer from a double emulsion system by a solvent diffusion process were used to produce 250-300 nm in diameter NPs. The cellular uptake of NPs was tested on a transformed human breast epithelial cell line, MCF-10A neoT, characterized by an increased expression of cysteine proteases and highly invasive cell phenotype. The influence of NPs on cell viability was evaluated by MTT test showing IC50 400 microg/ml for PLGA and 5 mg/ml for chitosan NPs. As determined by fluorescence microscopy chitosan NPs did not enter the cells during 1-hour incubation whereas the same amount of PLGA NPs were in the cells already after 5 min of incubation. Cystatin delivered into MCF-10A neoT cells by PLGA NPs effectively inhibited intracellular proteolytic activity of cathepsin B, as detected by specific fluorogenic substrate Z-Arg2 cresyl violet. On the contrary, free cystatin in solution did not internalise into the cells and inhibit cathepsin B. To conclude, PLGA NPs with cystatin but not chitosan NPs were targeted through endocytosis to the lysosomal compartments that are rich of proteases enzymes. Our results suggest new strategy to inactivate intracellular tumour-associated proteases, and consequently the invasion behaviour of tumour cells, which could contribute to cancer therapy.  相似文献   

5.
磁性羧甲基化壳聚糖纳米粒子的制备与表征   总被引:1,自引:1,他引:0  
以化学共沉淀法制备了Fe3O4纳米粒子,壳聚糖经羧甲基化改性后接枝在Fe3O4颗粒表面,得到了磁性羧甲基化壳聚糖(Fe3O4/CMC)纳米粒子.利用透射电镜(TEM)、X射线衍射(XRD)、傅立叶红外光谱(FT-IR)及磁性测试对产物进行了表征.TEM表明Fe3O4纳米粒子被CMC包覆,粒径约10 nm;XRD分析表明复合纳米粒子中磁性物质为Fe3O4;FT-IR表明壳聚糖发生羧甲基反应以及在Fe3O4表面的接枝反应.Fe3O4/CMC纳米粒子具有超顺磁性,比饱和磁化强度25.73 emu/g,有良好的磁稳定性.  相似文献   

6.
Gemcitabine is a chemotherapy drug used in different carcinomas, although because it displays a short biological half-life, its plasmatic levels can quickly drop below the effective threshold. Nanoparticle-based drug delivery systems can provide an alternative approach for regulating the bioavailability of this and most other anticancer drugs. In this work we describe a new model of composite nanoparticles consisting of a core of magnetite nanoparticles, coated with successive layers of high molecular weight poly(acrylic acid) and chitosan, and a final layer of folic acid. The possibility of using these self-assembled nanostructures for gemcitabine vehiculization is explored. First, the surface charge of the composite particles is studied by means of electrophoretic mobility measurements as a function of pH for poly(acrylic acid) (carbopol) of different molecular weights. The adsorption of folic acid, aimed at increasing the chances of the particles to pass the cell membrane, is followed up by optical absorbance measurements, which were also employed for drug adsorption determinations. As a main result, it is shown that gemcitabine adsorbs onto the surface of chitosan/carbopol-coated magnetite nanoparticles. In vitro experiments show that the functionalized magnetic nanoparticles are able to deliver the drug to the nuclei of liver, colon and breast tumor cells.  相似文献   

7.
Bovine pericardium, for cardiac valve fabrication, was coated with either chitosan or silk fibroin film. In vitro calcification tests of coated and non coated bovine pericardium were performed in simulated body fluid solution in order to investigate potential alternatives to minimize calcification on implanted heart valves. Complementary, morphology was assessed by scanning electron microscopy — SEM; X-ray diffraction (XRD) and infrared spectroscopy (FTIR-ATR) were performed for structural characterization of coatings and biocompatibility of chitosan. Silk fibroin films were assayed by in vitro cytotoxicity and endothelial cell growth tests. Bovine pericardium coated with silk fibroin or chitosan did not present calcification during in vitro calcification tests, indicating that these biopolymeric coatings do not induce bovine pericardium calcification. Chitosan and silk fibroin films were characterized as non cytotoxic and silk fibroin films presented high affinity to endothelial cells. The results indicate that bovine pericardium coated with silk fibroin is a potential candidate for cardiac valve fabrication, since the affinity of silk fibroin to endothelial cells can be explored to induce the tissue endothelization and therefore, increase valve durability by increasing their mechanical resistance and protecting them against calcification.  相似文献   

8.
Targeted delivery of nanoparticle (NP)‐based diagnostic and therapeutic agents to malignant cells and tissues has exclusively relied on chemotargeting, wherein NPs are surface‐coated with ligands that specifically bind to overexpressed receptors on malignant cells. Here, it is demonstrated that cellular uptake of NPs can also be biased to malignant cells based on the differential mechanical states of cells, enabling mechanotargeting. Owing to mechanotransduction, cell lines (HeLa and HCT‐8) cultured on hydrogels of various stiffness are directed into different stress states, measured by cellular force microscopies. In vitro NP delivery reveals that increases in cell stress suppress cellular uptake, counteracting the enhanced uptake that occurs with increases in exposed surface area of spread cells. Upon prolonged culture on stiff hydrogels, cohesive HCT‐8 cell colonies undergo metastatic phenotypic change and disperse into individual malignant cells. The metastatic cells are of extremely low stress state and adopt an unspread, 3D morphology, resulting in several‐fold higher uptake than the nonmetastatic counterparts. This study opens a new paradigm of harnessing mechanics for the design of future strategies in nanomedicine.  相似文献   

9.
Because nanoparticles are finding uses in myriad biomedical applications, including the delivery of nucleic acids, a detailed knowledge of their interaction with the biological system is of utmost importance. Here the size‐dependent uptake of gold nanoparticles (AuNPs) (20, 30, 50 and 80 nm), coated with a layer‐by‐layer approach with nucleic acid and poly(ethylene imine) (PEI), into a variety of mammalian cell lines is studied. In contrast to other studies, the optimal particle diameter for cellular uptake is determined but also the number of therapeutic cargo molecules per cell. It is found that 20 nm AuNPs, with diameters of about 32 nm after the coating process and about 88 nm including the protein corona after incubation in cell culture medium, yield the highest number of nanoparticles and therapeutic DNA molecules per cell. Interestingly, PEI, which is known for its toxicity, can be applied at significantly higher concentrations than its IC50 value, most likely because it is tightly bound to the AuNP surface and/or covered by a protein corona. These results are important for the future design of nanomaterials for the delivery of nucleic acids in two ways. They demonstrate that changes in the nanoparticle size can lead to significant differences in the number of therapeutic molecules delivered per cell, and they reveal that the toxicity of polyelectrolytes can be modulated by an appropriate binding to the nanoparticle surface.  相似文献   

10.
A general method of coating polymer/DNA nanoparticles was developed. Peptide coated nanoparticles were found to have favorable biophysical characteristics including small particle size, near-neutral zeta potential, and stability in serum. At appropriate formulation conditions including near-neutral charge ratio, the coated nanoparticles enabled effective ligand-specific gene delivery to human primary endothelial cells in serum-containing media. As this nanoparticulate drug delivery system has high efficacy, ligand-based specificity, biodegradability, and low cytotoxicity, it may be potentially useful in several clinical applications.  相似文献   

11.
The aim of this study was to prepare and characterize chitosan-coated microspheres containing cyclosporine A (CyA). Microspheres encapsulated with CyA were prepared by solvent evaporation-emulsification methods. Microspheres were immersed in chitosan solution (0.5% w/w) to be coated. Morphology, mean size, and encapsulation efficiency of chitosan-coated microspheres were evaluated. To assess the mucoadhesive properties of this drug delivery system, the percent of mucin adsorption to the surface of coated microspheres was determined. Microspheres were spherical in shape. Encapsulation efficiency of different microsphere formulations varied from 78% to 92%. According to the mucin adsorption results, this particulate system showed suitable mucoadhesive properties. It can be concluded that surface modification of microspheres by chitosan coating would increase the prospects of their usefulness as oral drug delivery systems for CyA.  相似文献   

12.
The aim of this study was to prepare and characterize chitosan-coated microspheres containing cyclosporine A (CyA). Microspheres encapsulated with CyA were prepared by solvent evaporation-emulsification methods. Microspheres were immersed in chitosan solution (0.5% w/w) to be coated. Morphology, mean size, and encapsulation efficiency of chitosan-coated microspheres were evaluated. To assess the mucoadhesive properties of this drug delivery system, the percent of mucin adsorption to the surface of coated microspheres was determined. Microspheres were spherical in shape. Encapsulation efficiency of different microsphere formulations varied from 78% to 92%. According to the mucin adsorption results, this particulate system showed suitable mucoadhesive properties. It can be concluded that surface modification of microspheres by chitosan coating would increase the prospects of their usefulness as oral drug delivery systems for CyA.  相似文献   

13.
Chitosan nanoparticles containing the anticancer drug paclitaxel were prepared by a solvent evaporation and emulsification crosslinking method. The physicochemical properties of the nanoparticles were characterized by various techniques, and uniform nanoparticles with an average particle size of 116 ± 15 nm with high encapsulation efficiencies (EE) were obtained. Additionally, a sustained release of paclitaxel from paclitaxel-loaded chitosan nanoparticles was successful. Using different ratios of paclitaxel-to-chitosan, the EE ranged from 32.2 ± 8.21% to 94.0 ± 16.73 %. The drug release rates of paclitaxel from the nanoparticles were approximately, 26.55 ± 2.11% and 93.44 ± 10.96% after 1 day and 13 days, respectively, suggesting the potential of the chitosan nanoparticles as a sustained drug delivery system. Cytotoxicity tests showed that the paclitaxel-loaded chitosan had higher cell toxicity than the individual paclitaxel and confocal microscopy analysis confirmed excellent cellular uptake efficiency. TEM images showed the ultrastructure changes of A2780 cells incubated with paclitaxel-loaded nanoparticles. Flow cytometric analysis revealed two subdiploid peaks for the cells in the paclitaxel-loaded nanoparticles and paclitaxel treated groups, respectively, with the intensity of the former higher than that of the latter. Moreover, the cell cycle was arrested in the G2-M phase, which was consistent with the action mechanism of the direct administration of paclitaxel. These results indicate that chitosan nanoparticles have potential uses as anticancer drug carriers and also have an enhanced anticancer effect.  相似文献   

14.
Intracellular drug delivery of layered double hydroxide (LDH) nanocarriers have been examined in human osteosarcoma Saos-2 cell culture line by both electron and confocal microscopies. For transmission electron microsopic (TEM) study, LDHs and anticancer drug, methotrexate (MTX) loaded LDHs were synthesized and the particle size was controlled. From the scanning electron microscopic (SEM) studies, morphologies of LDH nanoparticle and its MTX intercalated form were proven to be platelike hexagonal with an average size of approximately 150 nm. In order to understand the cellular penetration behavior, both nanoparticles were treated to human osteosarcoma Saos-2 cell culture lines and the cellular uptake pattern with respect to incubation time was observed by TEM and SEM. We observed that the nanoparticles are attached at the cellular membrane at first and then internalized into the cells via endocytosis within 1 h. Then are located in the intracellular vacuole (endosome). In order to examine the intracellular drug delivery mechanism of LDH nanoparticles, fluorescein 5-isothiocyanate (FITC) labeled MTX was intercalated into LDH and treated on Saos-2 cells. Laser scanning confocal microscopic studies revealed that the FITC-MTX molecules were first internalized with LDH nanocarriers via endocytosis, and located in endosome to deliver loaded drug to target cellular organ. It was, therefore, concluded that LDH could play a role as drug delivery nanocarriers.  相似文献   

15.
Polysaccharides based polyelectrolyte complex nanoparticles (PCNs) intended for use in the delivery of macromolecules were prepared by the self-assembly of deoxycholic acid hydrophobically modified chitosan (CS-DCA) core and then coated with sodium alginate (ALG) shell. The CS-DCA capable of forming nano-sized self-aggregates in medium was prepared by the grafting of DCA to CS. In order to increase the stability of nanoparticles and prevent burst release of drug in bloodstream, polyanionic ALG was coated on the surface of positively charged CS-DCA nanoparticles to form PCNs. Dynamic light scattering results revealed that the mean diameter of the PCNs was about 330 nm, larger than that of uncoated nanoparticles (~150 nm). The zeta potential was big enough to keep the stability of PCNs (?28 mV); no size change was found even upon 1 month storage. Bovine serum albumin could be easily incorporated into the PCNs with encapsulation efficiency (>44 %) and keep a sustained manner without burst release when exposed to PBS (pH 7.4) at 37 °C. These results suggested that PCNs may be a promising drug carrier for a prolonged and sustained delivery in the bloodstream.  相似文献   

16.
Phospholipid vesicles encapsulating magnetic nanoparticles (liposome complexes) have been prepared for targeting a drug to a specific organ using a magnetic force, as well as for local hyperthermia therapy. Liposome complexes are also an ideal platform for use as contrast agents of magnetic resonance imaging (MRI). We describe the preparation and characterization of liposomes containing magnetite. These liposomes were obtained by thin film hydration method and Fe3O4 nanoparticles were synthesized by coprecipitation method. They were characterized by an electrophoretic light scattering spectrophotometer, the liposome complexes were subsequently coated using chitosan. We have further investigated the ability of the above formulation for drug delivery and MRI applications. We are specifically interested in evaluating our liposome complexes for drug therapy; hence, we selected paclitaxel for the combination study. The amount of paclitaxel was measured at 227 nm using a UV-Vis spectrophotometer. Cytotoxicity of liposome complexes was treated with the various concentrations of paclitaxel in PC3 cell lines. The structure and properties of liposome complexes were analyzed by FT-IR, XRD and VSM. The particle size was analyzed by TEM and DLS.  相似文献   

17.
Recently discovered intratumoral diffusion resistance, together with poor solubility and nontargeted distribution of chemotherapeutic drugs, has significantly impaired the performance of cancer treatments. By developing a well‐designed droplet‐confined/cryodesiccation‐driven crystallization approach, we herein report the successful preparation of nanocrystallites of insoluble chemotherapeutic drug paclitaxel (PTX) in forms of nanodots (NDs, ≈10 nm) and nanoparticles (NPs, ≈70 nm) with considerably high drug loading capacity. Superficially coated Pluronic F127 is demonstrated to endow the both PTX nanocrystallites with excellent water solubility and prevent undesired phagocyte uptake. Further decoration with tumor‐penetrating peptide iRGD, as expected, indiscriminatively facilitates tumor cell uptake in traditional monolayer cell culture model. On the contrary, distinctly enhanced performances in inward penetration and ensuing elimination of 3D multicellular tumor spheroids are achieved by iRGD‐NDs rather than iRGD‐NPs, revealing the significant influence of particle size variation in nanoscale. In vivo experiments verify that, although efficient tumor enrichment is achieved by all nanocrystallites, only the iRGD‐grafted nanocrystallites of ultranano size realize thorough intratumoral delivery and reach cancer stem cells, which are concealed inside the tumor core. Consequently, much strengthened restriction on progress and metastasis of orthotopic 4T1 mammary adenocarcinoma is achieved in murine model, in sharp contrast to commercial PTX formulation Taxol.  相似文献   

18.
The objective of this study was to develop a nanoparticulate drug delivery system based on the surface modification of poly(lactide-co-glycolide) (PLGA) nanoparticles with a thiolated chitosan. PLGA nanoparticles were prepared by the emulsification-solvent evaporation method. Immobilization of chitosan to the surface of PLGA nanoparticles via amide bonds was mediated by a carbodiimide. Thiol groups were covalently bound to the chitosan surface of particles by reaction with 2-iminothiolane. Obtained nanoparticles were characterized in vitro regarding size, zeta potential, thiol group content, stability at different pH values, mucoadhesion, and drug release. Results demonstrated that the surface modification of PLGA nanoparticles with thiolated chitosan (chitosan-TBA) leads to nanoparticles of a mean diameter of 889.5 ± 72 nm and positive zeta potential of + 24.74 mV. The modified nanoparticles contained 7.32 ± 0.24 μmol thiol groups per gram nanoparticles. The size of nanoparticles was strongly influenced by the pH of the surrounding medium, being 925.0 ± 76.3 nm at pH 2 and 577.8 ± 66.7 nm at pH 7.4. Thiolated nanoparticles showed a 3.3-fold prolonged residence time on the mucosa and an unchanged release profile in comparison to unmodified PLGA nanoparticles. These data suggest that surface modified chitosan-TBA conjugate PLGA nanoparticles have the potential to be used as mucoadhesive drug delivery system.  相似文献   

19.
Lycopene (LYC) is known to protect cells from oxidative damage caused by free radicals in human tissues. In the present study, the authors designed a LYC‐loaded sialic acid (SA)‐conjugated poly(D,L‐lactide‐co‐glycolide) (PLGA) nanoparticle (LYC‐NP) to enhance the therapeutic efficacy of LYC in acute kidney injury. The characteristics of the LYC‐NPs were defined according to particle size, morphology, and in vitro drug release. The LYC‐NPs exhibited a controlled release of LYC over 48 h. Confocal laser scanning microscopy clearly highlighted the targeting potential of SA. Enhanced green fluorescence was observed for the LYC‐NPs in H2 O2 ‐treated human umbilical vein endothelial cells, indicating enhanced internalisation of NPs. The LYC‐NPs showed significantly greater cell viability than H2 O2 ‐treated cells. In addition, the LYC‐NPs remarkably reduced proinflammatory cytokine levels, attributable mainly to the increased cellular internalisation of the SA‐based carrier delivery system. Furthermore, protein levels of caspase‐3 and ‐9 were significantly down‐regulated after treatment with the LYC‐NPs. Overall, they have demonstrated that SA‐conjugated PLGA‐NPs containing LYC could be used to treat kidney injury.Inspec keywords: fluorescence, biomedical materials, biological tissues, cellular biophysics, drugs, proteins, molecular biophysics, injuries, drug delivery systems, kidney, nanomedicine, biochemistry, optical microscopy, nanoparticles, nanofabrication, cancer, toxicology, blood vessels, particle sizeOther keywords: sialic acid‐conjugated PLGA nanoparticles, chemotherapeutic drug‐induced kidney injury, LYC‐NP, LYC‐loaded sialic acid‐conjugated poly(D,L‐lactide‐co‐glycolide) nanoparticle, SA‐conjugated PLGA‐NP, protective effect, lycopene, human tissues, particle size, in vitro drug release, confocal laser scanning microscopy, green fluorescence, human umbilical vein endothelial cells, cell viability, proinflammatory cytokine levels, cellular internalisation, SA‐based carrier delivery system, time 48.0 hour  相似文献   

20.
The aim of this study was to explore the possibility of obtaining nanoparticles (NPs) containing high amounts of cyclodextrin (CD) derivatives such as carboxymethyl-β-CD and sulphobutyl ether-β-CD. The rationale used was to combine the drug solubilizing and stabilizing properties of cyclodextrins (CDs) with the mucoadhesive properties of chitosan (CS) in a unique nanoparticulate drug delivery system. The size of the resulting NPs was affected by the nature of the CDs, ranging between 275 and 550?nm, whereas the zeta potential of the NPs was always positive and close to +35?mV. The positive zeta values, together with the results from NMR studies, suggest that CS is the major compound on the surface of the NPs, while CD molecules are strongly associated with the NP matrix. The empirical composition of the NPs was quantified by elemental analysis and the results indicated that the amount of CD associated with the NPs was strictly dependent on its electrostatic charge. Finally, in vitro stability studies indicated that the presence of CDs in the NP structure can prevent the aggregation of this nanometric carrier system in simulated intestinal fluid. Overall, this new type of NP represents an attractive drug delivery platform of particular interest for the oral administration of drugs with low bioavailability.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号