This study provides an overview on green composites degradability. Practically, the main drawbacks of using natural fibers are their poor dimensional stability, degradability and high degree of moisture absorption. Wh...This study provides an overview on green composites degradability. Practically, the main drawbacks of using natural fibers are their poor dimensional stability, degradability and high degree of moisture absorption. While, end use of product from natural fiber filled or reinforced composites has become subject of concern to material engineers and scientist. The major properties of natural fiber reinforced polymer composites are greatly dependent on the hydrophilic tendency and dimensional stability of the fibers used, morphology aspect ratio for long fiber, while voids for powder fibers. The effects of chemical treatments on cellulosic fibers that are used as reinforcements for thermoplastics were studied. The chemical source for the treatments is alkalization. The significance of chemically-treated natural fibers is seen through the improvement of mechanical properties. The untreated fiber composites degrade faster in municipal soil compared to treated fiber composites.展开更多
In the past decade, various medicated nanofibrous scaffolds have been developed as effective drug delivery systems for postsurgical cancer treatment.In this study, hydroxyapatite nanoparticles( HANPs) were used as car...In the past decade, various medicated nanofibrous scaffolds have been developed as effective drug delivery systems for postsurgical cancer treatment.In this study, hydroxyapatite nanoparticles( HANPs) were used as carriers to load an anticancer agent—camptothecine( CPT),and the CPT-loaded HANPs( CPT@ HANPs) was then incorporated into poly( lactic-co-glycolic acid)( PLGA) nanofibers via electrospinning.Thus fabricated medicated nanofibrous mats( PLGA / CPT @ HANPs) were characterized by field emission scanning electron microscope( FESEM),transmission electron microscope( TEM), attenuated total reflection Fourier transform infrared spectroscopy( ATR-FTIR) and X-ray diffraction( XRD).The release profiles of CPT from the medicated electrospun mats were obtained and their in vitro anticancer efficacy against HeL a cells was also evaluated.The results showed that the CPT was successfully loaded onto the surface of HANPs,and the prepared electrospun mats exhibited a homogeneous and continuous morphology.Furthermore,the loaded CPT exhibited a sustained release behavior from the nanofibrous mats and the released CPT showed a long-term anticancer efficacy against HeL a cells.Therefore,the prepared medicated electrospun mats may be served as an effective drug delivery device for local antitumor treatment.展开更多
Poly（a-hydroxy octanoic acid） was first used as an additive for the preparation of electrospun ultra-fine fibers of poly（ethylene glycol）-b-poly（L-lactide） （PEG-PLLA）. Ibuprofen was loaded in the electrospun u...Poly（a-hydroxy octanoic acid） was first used as an additive for the preparation of electrospun ultra-fine fibers of poly（ethylene glycol）-b-poly（L-lactide） （PEG-PLLA）. Ibuprofen was loaded in the electrospun ultra-fine fibers. The results from environmental scanning electron microscopy （ESEM）, wide angle X-ray diffraction （WAXD） and differential scanning calorimetry （DSC） demonstrated that ibuprofen could be perfectly entrapped in the fibers electrospun from PEG-PLLA using a-hydroxy octanoic acid or PEG-b-poly（a-hydroxy octanoic acid） （PEG-PHOA） as additives. Compared with electrospun PEG-PLLA fibers which entrapped 20 wt% ibuprofen, the PEG-PLLA electrospun fibers containing PEG-PHOA exhibited integral and robust after 1 week incubated in 37℃, pH 7.4 phosphate buffer solution with 10 μg/mL proteinase K. Compared with electrospun fibers without PEG-PHOA, the concentration ofproteinase K in release media had less effect on the release rate of ibuprofen. An unique release profile was found from PEG-PLLA fiber after the incorporation of PEG-PHOA. Enzyme degradation experiments demonstrated that PEG-PHOA but not a-hydroxy octanoic acid monomer was the crucial factor for integrity maintenance of the electrospun fibers, which may be due to the enzyme degradation tolerance property of the PEG-PHOA polymer additive.展开更多
Objective: To prepare and characterize poly lactic-co-glycolic acid(PLGA) nanoparticles loaded with soluble leishmanial antigen or autoclaved leishmanial antigen and explore in vitro and in vivo immunogenicity of anti...Objective: To prepare and characterize poly lactic-co-glycolic acid(PLGA) nanoparticles loaded with soluble leishmanial antigen or autoclaved leishmanial antigen and explore in vitro and in vivo immunogenicity of antigen encapsulated nanoparticles. Methods: Water/oil/water double emulsion technique was employed to synthesize PLGA nanoparticles, and scanning electron microscopy, Fourier transform infrared spectroscopy and Zeta-potential measurements were used to identify the characteristics of nanoparticles. Cytotoxicity of synthetized nanoparticles on J774 macrophage were investigated by MTT assays. To determine the in vitro immunostimulatory efficacies of nanoparticles, griess reaction and ELISA was used to measure the amounts of NO and cytokines. During the in vivo analysis, Balb/c mice were immunized with vaccine formulations, and protective properties of nanoparticles were measured by Leishman Donovan unit in the liver following the infection. Cytokine levels in spleens of mice were determined by ELISA. Results: MTT assay showed that neither soluble leishmanial antigen nor autoclaved leishmanial antigen encapsulated nanoparticles showed cytotoxicity against J774 macrophage cells. Contrary to free antigens, both autoclaved leishmanial antigen-nanoparticle and soluble leishmanial antigen-nanoparticle formulations led to a 10 and 16-fold increase in NO amounts by macrophages, respectively. Leishman Donovan unit calculations revealed that soluble leishmanial antigen-nanoparticles and autoclaved leishmanial antigen-nanoparticles yielded 52% and 64% protection against visceral leishmaniasis in mouse models. Besides, in vitro and in vivo tests demonstrated that by increasing IFN-γ and IL-12 levels and inhibiting IL-4 and IL-10 secretions, autoclaved leishmanial antigen-nanoparticles and soluble leishmanial antigennanoparticles triggered Th1 immune response. Conclusions: Both autoclaved leishmanial antigen-nanoparticles and soluble leishmanial antigen-nanoparticles formulations provide exceptional in vitro and in vivo immunostimulatory activities. Hence, PLGA-based antigen delivery systems are recommended as potential vaccine candidates against visceral leishmaniasis.展开更多
文摘This study provides an overview on green composites degradability. Practically, the main drawbacks of using natural fibers are their poor dimensional stability, degradability and high degree of moisture absorption. While, end use of product from natural fiber filled or reinforced composites has become subject of concern to material engineers and scientist. The major properties of natural fiber reinforced polymer composites are greatly dependent on the hydrophilic tendency and dimensional stability of the fibers used, morphology aspect ratio for long fiber, while voids for powder fibers. The effects of chemical treatments on cellulosic fibers that are used as reinforcements for thermoplastics were studied. The chemical source for the treatments is alkalization. The significance of chemically-treated natural fibers is seen through the improvement of mechanical properties. The untreated fiber composites degrade faster in municipal soil compared to treated fiber composites.
基金National Natural Science Foundation of China(No.31271028)Shanghai Nano Science Program,China(No.11nm0505500)+1 种基金Innovation Program of Shanghai Municipal Education Commission,China(No.13ZZ051)Chinese Universities Scientific Fund(No.CUSF-DH-D-2014035)
文摘In the past decade, various medicated nanofibrous scaffolds have been developed as effective drug delivery systems for postsurgical cancer treatment.In this study, hydroxyapatite nanoparticles( HANPs) were used as carriers to load an anticancer agent—camptothecine( CPT),and the CPT-loaded HANPs( CPT@ HANPs) was then incorporated into poly( lactic-co-glycolic acid)( PLGA) nanofibers via electrospinning.Thus fabricated medicated nanofibrous mats( PLGA / CPT @ HANPs) were characterized by field emission scanning electron microscope( FESEM),transmission electron microscope( TEM), attenuated total reflection Fourier transform infrared spectroscopy( ATR-FTIR) and X-ray diffraction( XRD).The release profiles of CPT from the medicated electrospun mats were obtained and their in vitro anticancer efficacy against HeL a cells was also evaluated.The results showed that the CPT was successfully loaded onto the surface of HANPs,and the prepared electrospun mats exhibited a homogeneous and continuous morphology.Furthermore,the loaded CPT exhibited a sustained release behavior from the nanofibrous mats and the released CPT showed a long-term anticancer efficacy against HeL a cells.Therefore,the prepared medicated electrospun mats may be served as an effective drug delivery device for local antitumor treatment.
基金supported by the National Natural Science Foundation of China(Nos.20274048,50373043)the Chinese Academy of Sciences(No.KJCX2-SW-H07)the"863 project"(No.2002AA326100)
文摘Poly（a-hydroxy octanoic acid） was first used as an additive for the preparation of electrospun ultra-fine fibers of poly（ethylene glycol）-b-poly（L-lactide） （PEG-PLLA）. Ibuprofen was loaded in the electrospun ultra-fine fibers. The results from environmental scanning electron microscopy （ESEM）, wide angle X-ray diffraction （WAXD） and differential scanning calorimetry （DSC） demonstrated that ibuprofen could be perfectly entrapped in the fibers electrospun from PEG-PLLA using a-hydroxy octanoic acid or PEG-b-poly（a-hydroxy octanoic acid） （PEG-PHOA） as additives. Compared with electrospun PEG-PLLA fibers which entrapped 20 wt% ibuprofen, the PEG-PLLA electrospun fibers containing PEG-PHOA exhibited integral and robust after 1 week incubated in 37℃, pH 7.4 phosphate buffer solution with 10 μg/mL proteinase K. Compared with electrospun fibers without PEG-PHOA, the concentration ofproteinase K in release media had less effect on the release rate of ibuprofen. An unique release profile was found from PEG-PLLA fiber after the incorporation of PEG-PHOA. Enzyme degradation experiments demonstrated that PEG-PHOA but not a-hydroxy octanoic acid monomer was the crucial factor for integrity maintenance of the electrospun fibers, which may be due to the enzyme degradation tolerance property of the PEG-PHOA polymer additive.
基金supported by Scientific and Technological Research Council of Turkey(TUBITAK,Grant No.213S148)
文摘Objective: To prepare and characterize poly lactic-co-glycolic acid(PLGA) nanoparticles loaded with soluble leishmanial antigen or autoclaved leishmanial antigen and explore in vitro and in vivo immunogenicity of antigen encapsulated nanoparticles. Methods: Water/oil/water double emulsion technique was employed to synthesize PLGA nanoparticles, and scanning electron microscopy, Fourier transform infrared spectroscopy and Zeta-potential measurements were used to identify the characteristics of nanoparticles. Cytotoxicity of synthetized nanoparticles on J774 macrophage were investigated by MTT assays. To determine the in vitro immunostimulatory efficacies of nanoparticles, griess reaction and ELISA was used to measure the amounts of NO and cytokines. During the in vivo analysis, Balb/c mice were immunized with vaccine formulations, and protective properties of nanoparticles were measured by Leishman Donovan unit in the liver following the infection. Cytokine levels in spleens of mice were determined by ELISA. Results: MTT assay showed that neither soluble leishmanial antigen nor autoclaved leishmanial antigen encapsulated nanoparticles showed cytotoxicity against J774 macrophage cells. Contrary to free antigens, both autoclaved leishmanial antigen-nanoparticle and soluble leishmanial antigen-nanoparticle formulations led to a 10 and 16-fold increase in NO amounts by macrophages, respectively. Leishman Donovan unit calculations revealed that soluble leishmanial antigen-nanoparticles and autoclaved leishmanial antigen-nanoparticles yielded 52% and 64% protection against visceral leishmaniasis in mouse models. Besides, in vitro and in vivo tests demonstrated that by increasing IFN-γ and IL-12 levels and inhibiting IL-4 and IL-10 secretions, autoclaved leishmanial antigen-nanoparticles and soluble leishmanial antigennanoparticles triggered Th1 immune response. Conclusions: Both autoclaved leishmanial antigen-nanoparticles and soluble leishmanial antigen-nanoparticles formulations provide exceptional in vitro and in vivo immunostimulatory activities. Hence, PLGA-based antigen delivery systems are recommended as potential vaccine candidates against visceral leishmaniasis.
