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Effects of poly lactic-co-glycolic acid-Nogo A antibody delayed-release microspheres on regeneration of injured spinal cord in rats
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作者 Hai Lan Yueming Song 《Neural Regeneration Research》 SCIE CAS CSCD 2009年第5期358-364,共7页
BACKGROUND: Nogo A antigen is the major inhibiting factor blocking regeneration of the injured spinal cord. Neutralizing Nogo A antigens using Nogo A antibodies may help promote neurite regeneration and nervous funct... BACKGROUND: Nogo A antigen is the major inhibiting factor blocking regeneration of the injured spinal cord. Neutralizing Nogo A antigens using Nogo A antibodies may help promote neurite regeneration and nervous function recovery. For successful regeneration, sustained release of the antibody from a biodegradable material loaded with Nogo A antibodies to the injury site is required. OBJECTIVE: To compare the therapeutic effects of poly lactic-co-glycolic acid (PLGA)-Nogo A antibody delayed-release microspheres and Nogo A antibody alone on spinal regeneration in Sprague-Dawley rats with complete transverse injury to the spinal cord. DESIGN, TIME AND SETTING: A randomized, controlled animal trial was performed at the Pharmacological Laboratory of West China Center of Medical Sciences, Sichuan University, between October 2007 and January 2008. MATERIALS: Goat anti-rat Nogo A monoclonal antibody was purchased from Santa, American; goat anti-rat neurofilament 200 monoclonal antibody was from Zhongshan Goldenbridge, Beijing, China; PLGA-Nogo A antibody delayed-release microspheres were provided by the College of Pharmacy, Sichuan University. METHODS: A total of 36 adult female Sprague Dawley rats were used to establish models of completely transected spinal cord injury, at T10. Animals were randomly divided into three groups (n=12): model, Nogo A antibody alone, and Nogo A antibody delayed-release microsphere groups. After transverse injury of the spinal cord, 50 μ L normal saline solution, 50 μL normal saline solution containing 50μL g Nogo A antibody, and 50 μL normal saline solution containing 50 μg Nogo A antibody microspheres were administered to the respective groups at the injury site. MAIN OUTCOME MEASURES: The expression of Nogo A and neurofilament 200 in injured spinal cord was tested immunohistochemically, and motor function of rats was assessed by Basso-Beattie-Bresnahan (BBB) locomotor rating scale. RESULTS: Four weeks after injury, expression of Nogo A in microsphere group was significantly less than model and Nogo A antibody alone groups (P 〈 0.05); while there was no significant difference between model and Nogo A antibody alone groups (P 〉 0.05). Ten weeks after injury, microsphere group showed a significantly greater expression of neurofilament 200 than model and Nogo A antibody alone groups (P 〈 0.05); while no significant difference was found between model and Nogo A antibody alone groups (P 〉 0.05). At postoperative weeks 5 and 6, the score of BBB locomotor rating scale in microsphere group was significantly greater than the model group (P 〈 0.05), and at postoperative weeks 7 10, the score was much greater than model and Nogo A antibody alone groups (P 〈 0.05). CONCLUSION: Nogo A antibody delayed-release microspheres decreased Nogo A expression, increased neurofilament 200 expression in the injured spinal cord of rats, and promoted recovery of motor function through sustained drug release over a long-term period. 展开更多
关键词 Nogo A antibody MICROSPHERES poly lactic-co-glycolic acid spinal cord injury neural regeneration
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Efficient and selective upcycling of waste polylactic acid into acetate using nickel selenide
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作者 Bing Lan Yinfang Chen +4 位作者 Nantian Xiao Na Liu Chao Juan Chuan Xia Fan Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第10期575-584,I0012,共11页
The conversion of waste polylactic acid(PLA)plastics into high-value-added chemicals through electrochemical methods is a promising and sustainable approach.However,developing efficient and highly selective catalysts ... The conversion of waste polylactic acid(PLA)plastics into high-value-added chemicals through electrochemical methods is a promising and sustainable approach.However,developing efficient and highly selective catalysts for lactic acid oxidation reaction(LAOR)and understanding the reaction process are challenging.Here,we report the electrooxidation of waste PLA to acetate at a high current density of 100 mA cm-2 with high Faraday efficiency(~95%)and excellent stability(>100 h)over a nickel selenide nanosheet catalyst.In addition,a total Faraday efficiency of up to 190%was achieved for carboxylic acids,including acetic acid and formic acid,by coupling with the cathodic CO_(2) reduction reaction.In situ experimental results and theoretical simulations revealed that the catalytic activity center of LAOR was dynamically formed NiOOH species,and the surface-adsorbed SeO_(x) species accelerated the formation of Ni~(3+)species,thus promoting catalytic activity.The mechanism of lactic acid electrooxidation was further elucidated.Lactic acid was dehydrogenated to produce pyruvate first and then formed CH_3CO due to preferential C-C bond cleavage,resulting in the presence of acetate.This work demonstrated a sustainable method for recycling waste PLA and CO_(2) into high-value-added products. 展开更多
关键词 Waste plastic upcycling poly(lactic acid) Lactic acid electro-oxidation Acetic acid
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Poly(p-coumaric acid)nanoparticles alleviate temporomandibular joint osteoarthritis by inhibiting chondrocyte ferroptosis
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作者 Jiaxin Guo Kai Su +7 位作者 Liying Wang Bingyu Feng Xinru You Miao Deng Wei Seong Toh Jun Wu Bin Cheng Juan Xia 《Bioactive Materials》 SCIE CSCD 2024年第10期212-226,共15页
Oxidative stress and inflammation are key drivers of osteoarthritis(OA)pathogenesis and disease progression.Herein we report the synthesis of poly(p-coumaric)nanoparticles(PCA NPs)from p-courmaic acid(p-CA),a naturall... Oxidative stress and inflammation are key drivers of osteoarthritis(OA)pathogenesis and disease progression.Herein we report the synthesis of poly(p-coumaric)nanoparticles(PCA NPs)from p-courmaic acid(p-CA),a naturally occurring phytophenolic acid,to be a multifunctional and drug-free therapeutic for temporomandibular joint osteoarthritis(TMJOA).Compared to hyaluronic acid(HA)that is clinically given as viscosupplementation,PCA NPs exhibited long-term efficacy,superior anti-oxidant and anti-inflammatory properties in alleviating TMJOA and repairing the TMJ cartilage and subchondral bone in a rat model of TMJOA.Notably,TMJ repair mediated by PCA NPs could be attributed to their anti-oxidant and anti-inflammatory properties in enhancing cell proliferation and matrix synthesis,while reducing inflammation,oxidative stress,matrix degradation,and chondrocyte ferroptosis.Overall,our study demonstrates a multifunctional nanoparticle,synthesized from natural p-coumaric acid,that is stable and possess potent antioxidant,anti-inflammatory properties and ferroptosis inhibition,beneficial for treatment of TMJOA. 展开更多
关键词 Temporomandibular joint osteoarthritis poly(p-coumaric acid)nanoparticles Ferroptosis Oxidative pressure CARTILAGE
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Edaravone-loaded poly(amino acid) nanogel inhibits ferroptosis for neuroprotection in cerebral ischemia injury
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作者 Yunhan Zhang Zhulin Zou +5 位作者 Shuang Liu Fangfang Chen Minglu Li Haoyang Zou Haiyan Liu Jianxun Ding 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2024年第2期89-101,共13页
Neurological injury caused by ischemic stroke is a major cause of permanent disability and death. The currently available neuroprotective drugs fail to achieve desired therapeutic efficacy mainly due to short circulat... Neurological injury caused by ischemic stroke is a major cause of permanent disability and death. The currently available neuroprotective drugs fail to achieve desired therapeutic efficacy mainly due to short circulation half-life and poor blood−brain barrier (BBB) permeability. For that, an edaravone-loaded pH/glutathione (pH/GSH) dual-responsive poly(amino acid) nanogel (NG/EDA) was developed to improve the neuroprotection of EDA. The nanogel was triggered by acidic and EDA-induced high-level GSH microenvironments, which enabled the selective and sustained release of EDA at the site of ischemic injury. NG/EDA exhibited a uniform sub-spherical morphology with a mean hydrodynamic diameter of 112.3 ± 8.2 nm. NG/EDA efficiently accumulated at the cerebral ischemic injury site of permanent middle cerebral artery occlusion (pMCAO) mice, showing an efficient BBB crossing feature. Notably, NG/EDA with 50 µM EDA significantly increased neuron survival (29.3%) following oxygen and glucose deprivation by inhibiting ferroptosis. In addition, administering NG/EDA for 7 d significantly reduced infarct volume to 22.2% ± 7.2% and decreased neurobehavioral scores from 9.0 ± 0.6 to 2.0 ± 0.8. Such a pH/GSH dual-responsive nanoplatform might provide a unique and promising modality for neuroprotection in ischemic stroke and other central nervous system diseases. 展开更多
关键词 poly(amino acid)nanogel Controlled drug delivery Inhibition of ferroptosis NEUROPROTECTION Cerebral ischenia injury therapy
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Synergism of Zinc Oxide/Organoclay-Loaded Poly(lactic acid) Hybrid Nanocomposite Plasticized by Triacetin for Sustainable Active Food Packaging
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作者 Ponusa Songtipya Thummanoon Prodpran +1 位作者 Ladawan Songtipya Theerarat Sengsuk 《Journal of Renewable Materials》 EI CAS 2024年第5期951-967,共17页
The synergistic effect of organoclay(OC)and zinc oxide(ZnO)nanoparticles on the crucial properties of poly(lactic acid)(PLA)nanocompositefilms was systematically investigated herein.After their incorporation into PLA v... The synergistic effect of organoclay(OC)and zinc oxide(ZnO)nanoparticles on the crucial properties of poly(lactic acid)(PLA)nanocompositefilms was systematically investigated herein.After their incorporation into PLA via the solvent casting technique,the water vapor barrier property of the PLA/OC/ZnOfilm improved by a maximum of 86%compared to the neat PLAfilm without the deterioration of Young’s modulus or the tensile strength.Moreover,thefilm’s self-antibacterial activity against foodborne pathogens,including gram-negative(Escherichia coli,E.coli)and gram-positive(Staphylococcus aureus,S.aureus)bacteria,was enhanced by a max-imum of approximately 98–99%compared to the neat PLAfilm.Furthermore,SEM images revealed the homo-geneous dispersion of both nano-fillers in the PLA matrix.However,the thermal stability of thefilm decreased slightly after the addition of the OC and ZnO.Thefilm exhibited notable light barrier properties in the UV-Vis range.Moreover,the incorporation of a suitable biodegradable plasticizer significantly decreased the Tg and notably enhanced theflexibility of the nanocompositefilm by increasing the elongation at break approxi-mately 1.5-fold compared to that of the neat PLAfilm.This contributes to its feasibility as an active food packa-ging material. 展开更多
关键词 poly(lactic acid)nanocomposite ORGANOCLAY zinc oxide barrier property antibacterial activity active food packaging
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A novel artificial nerve graft for repairing longdistance sciatic nerve defects:a self-assembling peptide nanofiber scaffold-containing poly (lactic-co-glycolic acid) conduit 被引量:5
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作者 Xianghai Wang Mengjie Pan +7 位作者 Jinkun Wen Yinjuan Tang Audra D.Hamilton Yuanyuan Li Changhui Qian Zhongying Liu Wutian Wu Jiasong Guo 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第24期2132-2141,共10页
In this study, we developed a novel artificial nerve graft termed self-assembling peptide nanofiber scaffold (SAPNS)-containing poly(lactic-co-glycolic acid) (PLGA) conduit (SPC) and used it to bridge a 10-mm-... In this study, we developed a novel artificial nerve graft termed self-assembling peptide nanofiber scaffold (SAPNS)-containing poly(lactic-co-glycolic acid) (PLGA) conduit (SPC) and used it to bridge a 10-mm-long sciatic nerve defect in the rat. Retrograde tracing, behavioral testing and histomorphometric analyses showed that compared with the empty PLGA conduit implantation group, the SPC implantation group had a larger number of growing and extending axons, a markedly increased diameter of regenerated axons and a greater thickness of the myelin sheath in the conduit. Furthermore, there was an increase in the size of the neuromuscular junction and myofiber diameter in the target muscle. These findings suggest that the novel artificial SPC nerve graft can promote axonal regeneration and remyelination in the transected peripheral nerve and can be used for repairing peripheral nerve injury. 展开更多
关键词 nerve regeneration peripheral nerve defect artificial nerve graft polylactic-co-glycolic acid self-assembling peptide nanofiber scaffold REMYELINATION axon myelin neuromuscular junction NSFC grants neural regeneration
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Dorsal root ganglion-derived Schwann cells combined with poly(lactic-co-glycolic acid)/chitosan conduits for the repair of sciatic nerve defects in rats 被引量:3
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作者 Li Zhao Wei Qu +2 位作者 Yuxuan Wu Hao Ma Huajun Jiang 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第22期1961-1967,共7页
Schwann cells, nerve regeneration promoters in peripheral nerve tissue engineering, can be used to repair both the peripheral and central nervous systems. However, isolation and puriifcation of Schwann cells are compl... Schwann cells, nerve regeneration promoters in peripheral nerve tissue engineering, can be used to repair both the peripheral and central nervous systems. However, isolation and puriifcation of Schwann cells are complicated by contamination with ifbroblasts. Current reported measures are mainly limited by either high cost or complicated procedures with low cell yields or purity. In this study, we collected dorsal root ganglia from neonatal rats from which we obtained highly puriifed Schwann cells using serum-free melanocyte culture medium. The purity of Schwann cells (〉95%) using our method was higher than that using standard medium containing fetal bovine serum. The obtained Schwann cells were implanted into poly(lactic-co-glycolic acid)/chi-tosan conduits to repair 10-mm sciatic nerve defects in rats. Results showed that axonal diameter and area were signiifcantly increased and motor functions were obviously improved in the rat sciatic nerve tissue. Experimental ifndings suggest that serum-free melanocyte culture medium is conducive to purify Schwann cells and poly(lactic-co-glycolic acid)/chitosan nerve conduits combined with Schwann cells contribute to restore sciatic nerve defects. 展开更多
关键词 nerve regeneration Schwann cells dorsal root ganglia melanocyte medium FIBROBLASTS polylactic-co-glycolic acid CHITOSAN sciatic nerve defect NSFC grants neural regeneration
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Poly(lactic-co-glycolic acid) conduit for repair of injured sciatic nerve A mechanical analysis 被引量:1
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作者 Tao Yu Changfu Zhao +2 位作者 Peng Li Guangyao Liu Min Luo 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第21期1966-1973,共8页
Tensile stress and tensile strain directly affect the quality of nerve regeneration after bridging nerve defects by poly(lactic-co-glycolic acid) conduit transplantation and autogenous nerve grafting for sciatic ner... Tensile stress and tensile strain directly affect the quality of nerve regeneration after bridging nerve defects by poly(lactic-co-glycolic acid) conduit transplantation and autogenous nerve grafting for sciatic nerve injury. This study collected the sciatic nerve from the gluteus maximus muscle from fresh human cadaver, and established 10-mm-long sciatic nerve injury models by removing the ischium, following which poly(lactic-co-glycolic acid) conduits or autogenous nerve grafts were transplanted. Scanning electron microscopy revealed that the axon and myelin sheath were torn, and the vessels of basilar membrane were obstructed in the poly(lactic-co-glycolic acid) conduit-repaired sciatic nerve following tensile testing. There were no significant differences in tensile tests with autogenous nerve graft-repaired sciatic nerve. Following poly(lactic-co-glycolic acid) conduit transplantation for sciatic nerve repair, tensile test results suggest that maximum tensile load, maximum stress, elastic limit load and elastic limit stress increased compared with autogenous nerve grafts, but elastic limit strain and maximum strain decreased. Moreover, the tendencies of stress-strain curves of sciatic nerves were similar after transplantation of poly(lactic-co-glycolic acid) conduits or autogenous nerve grafts. Results showed that after transplantation in vitro for sciatic nerve injury, poly(lactic-co-glycolic acid) conduits exhibited good intensity, elasticity and plasticity, indicating that poly(lactic-co-glycolic acid) conduits are suitable for sciatic nerve injury repair. 展开更多
关键词 neural regeneration peripheral nerve injury sciatic nerve injury model polylactic-co-glycolic acid TRANSPLANTATION stress strain mechanical property grants-supported paper NEUROREGENERATION
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Transplantation of Nogo-66 receptor gene-silenced cells in a poly(D,L-lactic-co-glycolic acid) scaffold for the treatment of spinal cord injury 被引量:8
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作者 Dong Wang Yuhong Fan Jianjun Zhang 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第8期677-685,共9页
Inhibition of neurite growth, which is in large part mediated by the Nogo-66 receptor, affects neural regeneration following bone marrow mesenchymal stem cell transplantation. The tissue engineering scaffold poly(D,L... Inhibition of neurite growth, which is in large part mediated by the Nogo-66 receptor, affects neural regeneration following bone marrow mesenchymal stem cell transplantation. The tissue engineering scaffold poly(D,L-lactide-co-glycolic acid) has good histocompatibility and can promote the growth of regenerating nerve fibers. The present study used small interfering RNA to silence Nogo-66 receptor gene expression in bone marrow mesenchymal stem cells and Schwann cells, which were subsequently transplanted with poly(D,L-lactide-co-glycolic acid) into the spinal cord lesion regions in rats. Simultaneously, rats treated with scaffold only were taken as the control group. Hematoxylin-eosin staining and immunohistochemistry revealed that at 4 weeks after transplantation, rats had good motor function of the hind limb after treatment with Nogo-66 receptor gene-silenced ceils prus the poly(O,L-lactide-co-glycolic acid) scaffold compared with rats treated with scaffold only, and the number of bone marrow mesenchymal stem cells and neuron-like cells was also increased. At 8 weeks after transplantation, horseradish peroxidase tracing and transmission electron microscopy showed a large number of unmyelinated and myelinated nerve fibers, as well as intact regenerating axonal myelin sheath following spinal cord hemisection injury. These experimental findings indicate that transplantation of Nogo-66 receptor gene-silenced bone marrow mesenchymal stem cells and Schwann cells plus a poly(D,L-lactide-co-glycolic acid) scaffold can significantly enhance axonal regeneration of spinal cord neurons and improve motor function of the extremities in rats following spinal cord injury. 展开更多
关键词 neural regeneration spinal cord injury bone marrow mesenchymal stem cells Schwann cells poly(D L-lactide-co-glycolic acid Nogo-66 receptor gene rats gene silencing grants-supportedpaper photographs-containing paper neuroregeneration
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Evaluation of in vitro and in vivo immunostimulatory activities of poly(lactic-co-glycolic acid) nanoparticles loaded with soluble and autoclaved Leishmania infantum antigens: A novel vaccine candidate against visceral leishmaniasis 被引量:1
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作者 Emrah Sefik Abamor Adil Allahverdiyev +4 位作者 Ozlem Ayse Tosyali Melahat Bagirova Tayfun Acar Zeynep Mustafaeva Serap Derman 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2019年第8期353-364,共12页
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
关键词 VISCERAL LEISHMANIASIS Vaccine Delivery IMMUNOSTIMULANT poly lactic-co-glycolic acid(PLGA) Nanoparticle
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Viscoelasticity of repaired sciatic nerve by poly(lactic-co-glycolic acid) tubes 被引量:4
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作者 Chengdong Piao Peng Li +1 位作者 Guangyao Liu Kun Yang 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第33期3131-3138,共8页
Medical-grade synthetic poly(lactic-co-glycolic acid) polymer can be used as a biomaterial for nerve repair because of its good biocompatibility, biodegradability and adjustable degradation rate. The stress relaxati... Medical-grade synthetic poly(lactic-co-glycolic acid) polymer can be used as a biomaterial for nerve repair because of its good biocompatibility, biodegradability and adjustable degradation rate. The stress relaxation and creep properties of peripheral nerve can be greatly improved by repair with poly(lactic-co-glycolic acid) tubes. "Fen sciatic nerve specimens were harvested from fresh corpses within 24 hours of death, and were prepared into sciatic nerve injury models by creating a 10 mm defect in each specimen. Defects were repaired by anastomosis with nerve autografts and poly(lactic-co-glycolic acid) tubes. Stress relaxation and creep testing showed that at 7 200 seconds the sciatic nerve anastomosed by poly(lactic-co-glycolic acid) tubes exhibited a greater decrease in stress and increase in strain than those anastomosed by nerve autografts. These findings suggest that poly(lactic-co-glycolic acid) exhibits good viscoelasticity to meet the biomechanical require- ments for a biomaterial used to repair sciatic nerve injury. 展开更多
关键词 neural regeneration peripheral nerve injury sciatic nerve injury model nerve autograftpolylactic-co-glycolic acid TRANSPLANTATION repair stress relaxation CREEP biomaterialneuroregeneration
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Controlled release of cisplatin and cancer cell apoptosis with cisplatin encapsulated poly(lactic-co-glycolic acid) nanoparticles 被引量:1
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作者 A. Champa Jayasuriya Anthony J. Darr 《Journal of Biomedical Science and Engineering》 2013年第5期586-592,共7页
The goal of the present study is to utilize cis-diamminedichloroplatinum (cisplatin) loaded polymer nanoparticles (NPs) to give a controlled, extended, and local drug therapy for the treatment of cancer. We have used ... The goal of the present study is to utilize cis-diamminedichloroplatinum (cisplatin) loaded polymer nanoparticles (NPs) to give a controlled, extended, and local drug therapy for the treatment of cancer. We have used biodegradable and biocompatible poly(lactic-co-glycolic acid) (PLGA) to prepare the NPs by adjusting the double emulsion technique using poly(vinylalcohol) as a surface active agent. The PLGA NPs were characterized for particle size and shape, controlled release of cisplatin, and degradation. Cisplatin solubility in deionized water was increased up to 4 mg/mL by simply changing the solution parameters. Cisplatin encapsulated NPs were incubated in phosphate buffered saline (PBS) at 37?C to study the release kinetics of cisplatin. Cisplatin was released in a sustained manner with less than 20% release during a 3-day period followed by 50% release during a 21-day period. A degradation study of PLGA NPs demonstrated the loss of spherical shape during a 21-day period. We also examined the cisplatin sensitive A2780 cell apoptosis when cells were incubated with cisplatin encapsulated PLGA NPs. A large number of cell apoptosis occurred as a result of cisplatin release from the PLGA NPs. These results suggest that cisplatin encapsulated PLGA NPs can be used to treat the cancer cells by injecting them into a localized site minimizing the side effects. 展开更多
关键词 NANOPARTICLES CISPLATIN poly(lactic-co-glycolic acid) Controlled Release Cancer Apopotosis
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A porous poly(lactic-co-glycolic acid) scaffold induces innervation in a rabbit model of disc degeneration following annular injury
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作者 Long Xin Guocan Han +4 位作者 Fengdong Zhao Xing Zhao Wei Wang Changyou Gao ShunwuFan 《Neural Regeneration Research》 SCIE CAS CSCD 2009年第8期606-612,共7页
BACKGROUND: A degradable poly(lactic-co-glycolic acid) (PLGA) scaffold has been used to construct a degradable porous scaffold. This template can simulate the in vivo microenvironment and promote tissue formation... BACKGROUND: A degradable poly(lactic-co-glycolic acid) (PLGA) scaffold has been used to construct a degradable porous scaffold. This template can simulate the in vivo microenvironment and promote tissue formation. OBJECTIVE: To observe the histopathological changes during degeneration and regeneration of the intervertebral disc, and to analyze the effects of a PLGA scaffold on nerve fiber ingrowth into the lesion in vivo. DESIGN, TIME AND SETTING: A randomized, controlled animal experiment was performed at the Orthopaedic Laboratory, Clinic Medical Research Institution, Sir Run Run Shaw Hospital, Zhejiang University, from December 2007 to July 2008. MATERIALS: PLGA (China Textile Academy); growth-associated protein-43 (Life-span, USA); and protein gene product 9.5 antibody (AbD, United Kingdom) were used in this study. METHODS: Three consecutive segments of the intervertebral disc of thirty-two healthy adult male New Zealand rabbits were exposed, comprising L3-4, L4-5 and L5-6. Experimental intervertebral disc (L4-5 and L5-6) models were established by two different methods. In the test (trephine + scaffold) group, a 5-mm deep hole was drilled into the annulus fibrosus using a 3-mm diameter trephine, and the PLGA scaffold was implanted into the hole. In the acupuncture group, the remaining experimental intervertebral disc annulus fibrosus was damaged using a 16G needle at a depth of 5 mm. The L3-4 disc served as a control. MAIN OUTCOME MEASURES: Intervertebral disc degeneration was assessed using radiography, magnetic resonance imaging, and histological examination at various time points post-surgery. Nerve fiber ingrowth into the degenerated intervertebral disc was observed using immunohistochemical staining for growth-associated protein-43 and protein gene product 9.5. RESULTS: Compared with the normal controls, the heights of the damaged intervertebral discs were decreased, and T2 signal intensity was decreased in the test and acupuncture groups 2 weeks post-surgery. Intervertebral disc degeneration was faster in the test group than in the acupuncture group. PLGA was coated with newly formed tissue, gradually degraded, and absorbed, and could induce tissue ingrowth deep into the annulus fibrosus. Results of immunohistochemical staining showed that nerve fibers were distributed in newly formed tissue in the test group, and in the superficial layer or surrounding scar tissue in the acupuncture group. CONCLUSION: A porous PLGA scaffold provides an important biological channel to induce nerve fiber ingrowth deep into the degenerated intervertebral disc. 展开更多
关键词 annulus fibrosus damage intervertebral disc degeneration polylactic-co-glycolic acid scaffold nerve ingrowth
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Degradation mechanisms of poly (lactic-co-glycolic acid) films in vitro under static and dynamic environment 被引量:2
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作者 黄莹莹 齐民 +2 位作者 张萌 刘洪泽 杨大智 《中国有色金属学会会刊:英文版》 CSCD 2006年第B01期293-297,共5页
To understand their degradation mechanisms, PLGA (50:50) polymer films were prepared and eroded in the static and dynamic medium system. The degradation behavior was characterized through weight-average molecular weig... To understand their degradation mechanisms, PLGA (50:50) polymer films were prepared and eroded in the static and dynamic medium system. The degradation behavior was characterized through weight-average molecular weight change, mass loss, water uptake, etc. The results show that in dynamic system, significant mass loss begins until 10 d while mass loss does not begin until 30 d later, while weight-average molecular weight decreases observably at the beginning, and the appeasable mass loss happens in 20 d in static system, which suggests that the dynamic degradation rate is slower even than degradation in static medium. A mechanism was proposed that specimens in static medium take up water homogeneously and cause the polymer chains to degrade all over the specimen cross sections, which creates free carboxylic acid groups which lead to a decrease of pH value inside the swollen polymer and accelerate degradation of the polymer. While pH value inside polymer keeps constant in dynamic medium because of flowing of simulated medium, which make the hydrolytic cleavage of ester bonds inside specimen delayed. 展开更多
关键词 聚乳酸-乙醇酸共聚物 薄膜 水解 降解机制 静力环境 动力环境 缓释体系
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Preparation,Characterization,and Antitumor Efficacy of Camptothecine-Loaded Hydroxyapatite / Poly( lactic-co-glycolic acid ) Composite Nanofibers via Electrospinning
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作者 冯炜 陈梦霞 +3 位作者 陈良 尹郅祺 聂伟 何创龙 《Journal of Donghua University(English Edition)》 EI CAS 2014年第5期561-565,共5页
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
关键词 poly (-lactic-co-glycolic acid) ( PLGA ) HYDROXYAPATITE camptothecine NANOFIBER ANTICANCER
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A Study of Surface Modification of Poly(lactic-co-glycolic) Acid Using Argon Ion Irradiation
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作者 Ananta Raj Adhikari Buddhi Prasanga Tilakaratne +1 位作者 Dharshana Wijesundera Wei-Kan Chu 《Journal of Surface Engineered Materials and Advanced Technology》 2014年第6期326-331,共6页
The effect of Argon ion irradiation to the surface properties of poly(lactic-co-glycolic) acid (PLGA) was studied. A beam of 170 keV Argon ions was implanted at different fluencies (1 × 1012, 1 × 1013, 1 ... The effect of Argon ion irradiation to the surface properties of poly(lactic-co-glycolic) acid (PLGA) was studied. A beam of 170 keV Argon ions was implanted at different fluencies (1 × 1012, 1 × 1013, 1 × 1014, and 1 × 1015 ions/cm2). X-ray photoelectron spectroscopy (XPS) was used to analyze the evolution of the bonding microstructure of PLGA due to irradiation. Surface morphology was monitored using atomic force microscopy (AFM). AFM analysis shows that film roughness increased to maximum at the dose of 1 × 1014 ions/cm2 where the formations of hillocks were also detected. Hydrophilicity of PLGA is important for their applications in biomedicine such as bioscaffolds. Hydrophilicity was monitored using water contact angle measurements for both unmodified and ion-modified PLGA. It was observed that hydrophilicity of PLGA changes with the ion irradiation. This demonstrates that ion irradiation can be an alternative approach to control hydrophilicity of PLGA. PLGA scaffolds modified with ion irradiation could therefore be more suitable for the biomedical applications. 展开更多
关键词 poly(lactic-co-glycolic) acid SCAFFOLD Surface Modification Ion Irradiation
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One-Step Preparation of Poly-Lactic-Co-Glycolic-Acid Microparticles to Prevent the Initial Burst Release of Encapsulated Water-Soluble Proteins
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作者 Hiroyuki Takabe Moriyuki Ohkuma +2 位作者 Yasunori Iwao Shuji Noguchi Shigeru Itai 《Pharmacology & Pharmacy》 2013年第8期578-583,共6页
An initial burst is often observed during the release of active pharmaceutical ingredients (APIs) from poly-lactic-coglycolic-acid (PLGA) microparticles (MPs) which have been prepared by the emulsion-solvent evaporati... An initial burst is often observed during the release of active pharmaceutical ingredients (APIs) from poly-lactic-coglycolic-acid (PLGA) microparticles (MPs) which have been prepared by the emulsion-solvent evaporation method. Herein, we describe the development of a simple one-step coating method that suppresses the initial burst release process. This new method involves coating the PLGA-MPs with PLGA, with the coating process being performed through the phase separation of PLGA on the surface of PLGA-MPs using the emulsion-solvent evaporation method. Bovine serum albumin (BSA) was encapsulated in the PLGA-MPs as a model API. The coated MPs were spherical in shape with no pores on their smooth surface, whereas the non-coated PLGA-MPs had porous surfaces. An in vitro release study showed that the residual levels of BSA in the coated and non-coated PLGA-MPs after 1 h were about 99% and 16% of the original loads, respectively. The one-step coating method therefore represents a useful method for preparing PLGA-MPs that do not give an initial burst release of proteinaceous APIs. 展开更多
关键词 poly-lactic-co-glycolic-acid Microparticle Suppression of INITIAL Burst Release Coating Bovine Serum Albumin
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Poly(lactic acid)-aspirin microspheres prepared via the traditional and improved solvent evaporation methods and its application performances 被引量:1
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作者 Xiaolin Pan Mengyuan Gao +3 位作者 Yun Wang Yanping He Tian Si Yanlin Sun 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第8期194-204,共11页
Drug-loaded microspheres are significant for the development of modern pharmaceutical products. It is well known that the taken of aspirin for long-term increases the risk of serious gastrointestinal complications, th... Drug-loaded microspheres are significant for the development of modern pharmaceutical products. It is well known that the taken of aspirin for long-term increases the risk of serious gastrointestinal complications, therefore a controllable delivery of aspirin is of importance to lighten those side effects. In this work, poly(lactic acid)(PLA) was chosen as the carrier to prepare PLA-aspirin microspheres by using the traditional and the improved solvent evaporation methods. It was found that no matter which experimental condition was, the encapsulation efficiency of aspirin was higher by using the improved method than that of the traditional method. Specifically, when the concentration of polyvinyl alcohol = 1%(mass),the polymer concentration = 1:20, the oil/water rate = 1:2.5, PLA-aspirin microspheres were obtained via the improved method with a high yield of 82.83%(mass) and an encapsulation efficiency of 44.09%. PLAaspirin microspheres were then prepared continuously using the improved method, which further enhanced the encapsulation efficiency to 54.56%. Approximate 85% aspirin released from microspheres within 7 days. Obvious degradation which was represented by reduction on hardness was observed by soaking microspheres in PBS for 60 days. This work is of interest because it provides a continuous route to prepare PLA-aspirin microspheres continuously with a high drug encapsulation efficiency. 展开更多
关键词 ASPIRIN Degradation Foam-transfer MICROSPHERES poly(lactic acid) Slow-release
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High-performance and robust high-temperature polymer electrolyte membranes with moderate microphase separation by implementation of terphenyl-based polymers
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作者 Jinyuan Li Congrong Yang +3 位作者 Haojiang Lin Jicai Huang Suli Wang Gongquan Sun 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期572-578,共7页
Acid loss and plasticization of phosphoric acid(PA)-doped high-temperature polymer electrolyte membranes(HT-PEMs)are critical limitations to their practical application in fuel cells.To overcome these barriers,poly(te... Acid loss and plasticization of phosphoric acid(PA)-doped high-temperature polymer electrolyte membranes(HT-PEMs)are critical limitations to their practical application in fuel cells.To overcome these barriers,poly(terphenyl piperidinium)s constructed from the m-and p-isomers of terphenyl were synthesized to regulate the microstructure of the membrane.Highly rigid p-terphenyl units prompt the formation of moderate PA aggregates,where the ion-pair interaction between piperidinium and biphosphate is reinforced,leading to a reduction in the plasticizing effect.As a result,there are trade-offs between the proton conductivity,mechanical strength,and PA retention of the membranes with varied m/p-isomer ratios.The designed PA-doped PTP-20m membrane exhibits superior ionic conductivity,good mechanical strength,and excellent PA retention over a wide range of temperature(80–160°C)as well as satisfactory resistance to harsh accelerated aging tests.As a result,the membrane presents a desirable combination of performance(1.462 W cm^(-2) under the H_(2)/O_(2)condition,which is 1.5 times higher than that of PBI-based membrane)and durability(300 h at 160°C and 0.2 A cm^(-2))in the fuel cell.The results of this study provide new insights that will guide molecular design from the perspective of microstructure to improve the performance and robustness of HT-PEMs. 展开更多
关键词 Fuel cell High-temperature polymer electrolyte membranes Microphase separation poly(terphenyl piperidinium)s Phosphoric acid
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Removal of manganese from waste water by complexation-ultrafiltration using copolymer of maleic acid and acrylic acid 被引量:2
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作者 邱运仁 毛廉君 王伟华 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期1196-1201,共6页
Copolymer of maleic acid and acrylic acid (PMA-100), combining with polyvinyl butyral (PVB) ultrafiltration membrane was used for the removal of Mn(II) from waste water by complexation-ultrafiltration. The carbo... Copolymer of maleic acid and acrylic acid (PMA-100), combining with polyvinyl butyral (PVB) ultrafiltration membrane was used for the removal of Mn(II) from waste water by complexation-ultrafiltration. The carboxylic group content of PMA-100 and the rate of complexation reaction were measured. Effects of the mass ratio of PMA-100 to Mn(II) (n), pH, background electrolyte, etc on the rejection rate (R) and permeate flux (J) were investigated. The results show that carboxylic group content of PMA-100 is 9.5 mmol/g. The complexation of Mn(II) with PMA-100 is rapid and completed within 5 min at pH 6.0. Both R and J increase with pH increasing in the range of 2.5-7.0, and R increases with the increase of n at pH 6.0 while J is little affected. The background electrolyte leads to the decrease of R, and CaCl2 has much greater effect on R than NaCl at the same ionic strength. 展开更多
关键词 complexation-ultrafitration copolymer of maleic acid and acrylic acid poly (vinyl butyral) hollow fiber membrane MANGANESE wastewater treatment
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