WorldWideScience

Sample records for biodegradable polylactic acid

  1. [Progress on biodegradation of polylactic acid--a review].

    Science.gov (United States)

    Li, Fan; Wang, Sha; Liu, Weifeng; Chen, Guanjun

    2008-02-01

    Polylactic acid is a high molecular-weight polyester made from renewable resources such as corn or starch. It is a promising biodegradable plastic due to its mechanical properties, biocompatibility and biodegradability. To achieve natural recycling of polylactic acid, relative microorganisms and the underlying mechanisms in the biodegradation has become an important issue in biodegradable materials. Up to date, most isolated microbes capable of degrading polylactic acid belong to actinomycetes. Proteases secreted by these microorganisms are responsible for the degradation. However, subtle differences exist between these polylactic acid degrading enzymes and typical proteases with respect to substrate binding and catalysis. Amino acids relative to catalysis are postulated to be highly plastic allowing their catalytic hydrolysis of polylactic acid. In this paper we reviewed current studies on biodegradation of polylactic acid concerning its microbial, enzymatic reactions and the possible mechanisms. We also discussed the probability of biologically recycling PLA by applying highly efficient strains and enzymes. PMID:18438013

  2. Biodegradability of injection molded bioplastics containing polylactic acid and poultry feather fiber

    Science.gov (United States)

    Biodegradability of three types of bioplastic pots was evaluated by measuring carbon dioxide (CO2) produced from lab-scale compost reactors containing mixtures of pot fragments and compost inoculum held at 58 C for 60 days. Biodegradability of pot type A (composed of 100% polylactic acid (PLA)) was...

  3. Biodegradable polylactic acid polymer with nisin for use in antimicrobial food packaging

    Science.gov (United States)

    Biodegradable polylactic acid (PLA) polymer was evaluated for its application as a material for antimicrobial food packaging. PLA films were incorporated with nisin to provide slow release of the encapsulated antimicrobial for control of foodborne pathogens. Antimicrobial activity of PLA/nisin films...

  4. Effect of an acid filler on hydrolysis and biodegradation of poly-lactic acid (PLA)

    Science.gov (United States)

    Iozzino, Valentina; Speranza, Vito; Pantani, Roberto

    2015-12-01

    The use of biodegradable polymers is certainly an excellent strategy to solve many of the problems related to the disposal of the traditional polymers, whose accumulation in the environment is harmful and damaging. In order to optimize the use of biodegradable polymers, it is very important to understand and control the transformation processes, the structures and the morphologies resulting from the process conditions used to produce the articles and, not least, the biodegradation. The latter is strictly dependent on the just mentioned variables. The poly-lactic acid, PLA, is a biodegradable polymer. Many studies have been carried out on the degradation process of this polymer. In the course of this work we performed degradation tests on the PLA, with a specific D-isomer content, having amorphous structure, and in particular of biodegradation and hydrolysis. An acid chemical, fumaric acid, was added to PLA with the objective of controlling the rate of hydrolysis and of biodegradation. The hydrolysis process was followed, as function of time, by means of different techniques: pH variation, variation of weight of samples and variation of crystallinity degree and glass transition temperature using DSC analysis. The samples were also analyzed in terms of biodegradability by means of a homemade respirometer apparatus, in controlled composting conditions.

  5. Mechanical, thermal, and biodegradable properties of polylactic acid (PLA)/coir fibre biocomposites

    Science.gov (United States)

    Dong, Y.; Ghataura, A.; Haroosh, H. J.

    2013-08-01

    Polylactic acid (PLA)/coir fibre biocomposites were fabricated using a compression moulding technique. The effects of fibre content (5-30 wt%) and fibre treatment on mechanical, thermal and biodegradable properties of biocomposites were holistically investigated via mechanical testing, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and soil burial method to understand the applicability of manufacturing eco-efficient and sustainable "green composites".

  6. Biodegradability of injection molded bioplastic pots containing polylactic acid and poultry feather fiber.

    Science.gov (United States)

    Ahn, H K; Huda, M S; Smith, M C; Mulbry, W; Schmidt, W F; Reeves, J B

    2011-04-01

    The biodegradability of three types of bioplastic pots was evaluated by measuring carbon dioxide produced from lab-scale compost reactors containing mixtures of pot fragments and compost inoculum held at 58 °C for 60 days. Biodegradability of pot type A (composed of 100% polylactic acid (PLA)) was very low (13 ± 3%) compared to literature values for other PLA materials. Near infrared spectroscopy (NIRS) results suggest that the PLA undergoes chemical structural changes during polymer extrusion and injection molding. These changes may be the basis of the low biodegradability value. Biodegradability of pot types B (containing 5% poultry feather, 80% PLA, 15% starch), and C (containing 50% poultry feather, 25% urea, 25% glycerol), were 53 ± 2% and 39 ± 3%, respectively. More than 85% of the total biodegradation of these bioplastics occurred within 38 days. NIRS results revealed that poultry feather was not degraded during composting. PMID:21320772

  7. Biodegradation of poly(lactic acid) and some of its based systems with Trichoderma viride.

    Science.gov (United States)

    Lipsa, Rodica; Tudorachi, Nita; Darie-Nita, Raluca Nicoleta; Oprică, Lacramioara; Vasile, Cornelia; Chiriac, Aurica

    2016-07-01

    The purpose of this study was to assess the biodegradation of poly(lactic acid) (PLA) and some plasticized PLA based systems by Trichoderma viride fungus, in liquid medium and controlled laboratory conditions. The studied systems were achieved using PLA, hydrolyzed collagen (HC) as biological macromolecules and other additives by melt processing procedure. PLA and the systems' biodegradability was examined by the weight losses of the samples (after 7 and 21 days of exposure) and FTIR-ATR, GPC, SEM analyses (after 21 fungus inoculation days). The thermogravimetry (TG-DTG) study showed that the thermostability of the samples decreased after biodegradation and was influenced by the chemical structure of the systems' components. PMID:27064086

  8. Biodegradable Polylactic Acid (PLA) Microstructures for Scaffold Applications

    CERN Document Server

    Wang, G -J; Hsueh, C -C

    2008-01-01

    In this research, we present a simple and cost effective soft lithographic process to fabricate PLA scaffolds for tissue engineering. In which, the negative photoresist JSR THB-120N was spun on a glass subtract followed by conventional UV lithographic processes to fabricate the master to cast the PDMS elastomeric mold. A thin poly(vinyl alcohol) (PVA) layer was used as a mode release such that the PLA scaffold can be easily peeled off. The PLA precursor solution was then cast onto the PDMS mold to form the PLA microstructures. After evaporating the solvent, the PLA microstructures can be easily peeled off from the PDMS mold. Experimental results show that the desired microvessels scaffold can be successfully transferred to the biodegradable polymer PLA.

  9. Biodegradable poly(lactic acid) microspheres containing total alkaloids of Caulis sinomenii

    Indian Academy of Sciences (India)

    Wen Zhang; Xiaojie Lin; Xingxiang Zhang

    2011-12-01

    The fabrication of biodegradable poly(lactic acid) (PLA) microspheres containing total alkaloids of Caulis sinomenii was investigated. The formation, diameter, morphology and properties of the microspheres were characterized using Fourier transform infrared spectroscopy (FT–IR), laser particle size analyser and scanning electron microscopy (SEM), etc. In vitro releasing behaviour was also investigated using UV-Vis spectrometer. As a result, the drug-loaded microspheres with a narrower distributive, rounder and smoother surface were prepared. Drug-releasing behaviour from microspheres was affected by the concentration of emulsifier and the stirring rate. The results demonstrated that a medicated system, which can be potentially applied within a drug delivery system, was designed. This system acts in a systematic manner for the treatment of rheumatoid arthritis.

  10. Disposal Options of Bamboo Fabric-Reinforced Poly(Lactic) Acid Composites for Sustainable Packaging: Biodegradability and Recyclability

    OpenAIRE

    M.R. Nurul Fazita; Krishnan Jayaraman; Debes Bhattacharyya; Md. Sohrab Hossain; Mohamad Haafiz, M. K.; Abdul Khalil H.P.S.

    2015-01-01

    The present study was conducted to determine the recyclability and biodegradability of bamboo fabric-reinforced poly(lactic) acid (BF-PLA) composites for sustainable packaging. BF-PLA composite was recycled through the granulation, extrusion, pelletization and injection processes. Subsequently, mechanical properties (tensile, flexural and impact strength), thermal stability and the morphological appearance of recycled BF-PLA composites were determined and compared to BF-PLA composite (initial...

  11. Biodegradable Poly(Lactic Acid)/Multiwalled Carbon Nanotube Nanocomposite Fabrication Using Casting And Hot Press Techniques

    OpenAIRE

    Park S.G.; Abdal-Hay A.; Lim J.K.

    2015-01-01

    Biodegradable advanced polymer composites have recently received a large amount of attention. The present study aimed to design poly(lactic acid) multiwalled carbon nanotube nanocomposites (PLA/MWCNTs) using a simple fabrication technique. A PLA sheet was first dissolved in dichloromethane, and MWCNTs were subsequently added at various concentrations (0.5, 1.5 and 5%) while applying shear strain stirring to achieve dispersion of carbon nanotubes (CNTs). These solutions were then molded and a ...

  12. Weathering and Biodegradation Study on Graft Copolymer Compatibilized Hybrid Bionanocomposites of Poly(Lactic Acid)

    Science.gov (United States)

    Sajna, VP; Nayak, Sanjay K.; Mohanty, Smita

    2016-07-01

    This work reports on the influence of moisture absorption and accelerated weathering on the properties of graft copolymer compatibilized bionanocomposites of poly(lactic acid) (PLA). Moisture absorption tests were conducted for 30 days by immersing the samples in a distilled water bath at room temperature, and the amount of moisture absorbed in each time interval was measured. The rate of moisture uptake decreased by incorporation of C30B nanoclay and graft copolymer into fiber-reinforced PLA composites. Changes in the mechanical properties of composites in each time interval of moisture absorption were investigated using tensile and impact tests. Exposure to moisture caused significant drops in the mechanical properties. The morphological characterization of biocomposites during the aforementioned tests has been made using SEM, while bionanocomposites were analyzed by TEM. Further, this paper also reported the effect of accelerated weathering on the mechanical properties and the results are confirmed through SEM analysis. Biodegradation behaviors of PLA biocomposites and bionanocomposites have also been studied.

  13. Cold Oxygen Plasma Treatments for the Improvement of the Physicochemical and Biodegradable Properties of Polylactic Acid Films for Food Packaging.

    Science.gov (United States)

    Song, Ah Young; Oh, Yoon Ah; Roh, Si Hyeon; Kim, Ji Hyeon; Min, Sea C

    2016-01-01

    The effects of cold plasma (CP) treatment on the physicochemical and biodegradable properties of polylactic acid (PLA) films were studied. The PLA films were exposed to CP for 40 min at 900 W and 667 Pa using oxygen as the plasma-forming gas. The tensile, optical, and dynamic mechanical thermal properties, surface morphology, printability, water contact angle, chemical structure, weight change, and biodegradability properties of the films were evaluated during storage for up to 56 d. The tensile and optical properties of the PLA films were not significantly affected by CP treatment (CPT; P > 0.05). The surface roughness and water contact angle of PLA films increased by CPT and further increased during storage for 56 d. The printability of the PLA films increased following CPT and remained stable throughout the storage period. CP-induced hydrophilicity was also sustained during the storage period. The PLA films lost 1.9% of their weight after CPT, but recovered 99.5% of this loss after 14 d in storage. Photodegradation, thermal, and microbial biodegradable properties of the films were significantly improved by CPT (P < 0.05). Accelerated biodegradation of CP-treated PLA sachets with and without cheese was observed in compost. These results demonstrate the potential of CPT for modifying the stiffness, water contact angle, and chemical structure of PLA films and improving the printability and biodegradability of the films for food packaging.

  14. Disposal Options of Bamboo Fabric-Reinforced Poly(Lactic Acid Composites for Sustainable Packaging: Biodegradability and Recyclability

    Directory of Open Access Journals (Sweden)

    M.R. Nurul Fazita

    2015-08-01

    Full Text Available The present study was conducted to determine the recyclability and biodegradability of bamboo fabric-reinforced poly(lactic acid (BF-PLA composites for sustainable packaging. BF-PLA composite was recycled through the granulation, extrusion, pelletization and injection processes. Subsequently, mechanical properties (tensile, flexural and impact strength, thermal stability and the morphological appearance of recycled BF-PLA composites were determined and compared to BF-PLA composite (initial materials and virgin PLA. It was observed that the BF-PLA composites had the adequate mechanical rigidity and thermal stability to be recycled and reused. Moreover, the biodegradability of BF-PLA composite was evaluated in controlled and real composting conditions, and the rate of biodegradability of BF-PLA composites was compared to the virgin PLA. Morphological and thermal characteristics of the biodegradable BF-PLA and virgin PLA were obtained by using environment scanning electron microscopy (ESEM and differential scanning calorimetry (DSC, respectively. The first order decay rate was found to be 0.0278 and 0.0151 day−1 in a controlled composting condition and 0.0008 and 0.0009 day−1 in real composting conditions for virgin PLA and BF-PLA composite, respectively. Results indicate that the reinforcement of bamboo fabric in PLA matrix minimizes the degradation rate of BF-PLA composite. Thus, BF-PLA composite has the potential to be used in product packaging for providing sustainable packaging.

  15. Polylactic acid coating on a biodegradable magnesium alloy: An in vitro degradation study by electrochemical impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Alabbasi, Alyaa; Liyanaarachchi, S.; Kannan, M. Bobby, E-mail: bobby.mathan@jcu.edu.au

    2012-09-30

    Polylactic acid (PLA) was coated on a biodegradable magnesium alloy, AZ91, using spin coating technique for temporary implant applications. The degradation behaviour of the coated alloy samples was evaluated using electrochemical impedance spectroscopy (EIS) method in simulated body fluid (SBF). EIS results suggested that the PLA coating enhanced the degradation resistance of the alloy significantly. Increase in the PLA coating thickness was found to increase the degradation resistance, but resulted in poor adhesion. Long-term EIS experiments of the PLA coated samples suggested that their degradation resistance gradually decreased with increase in SBF exposure time. However, the degradation resistance of the PLA coated samples was significantly higher than that of the bare metal even after a 48 h exposure to SBF. - Highlights: Black-Right-Pointing-Pointer Polylactic acid (PLA) was coated on a magnesium-based alloy. Black-Right-Pointing-Pointer PLA coating enhanced the in vitro degradation resistance of the alloy. Black-Right-Pointing-Pointer Increase in the PLA coating thickness improved the alloy degradation resistance. Black-Right-Pointing-Pointer Thin film PLA coating exhibited both good degradation resistance and adhesion.

  16. Novel ultrasound contrast agents--Biodegradable poly(lactic acid) microcapsules

    Institute of Scientific and Technical Information of China (English)

    王身国; 崔文瑾; 李光明; 蔡晴; 智光; 赵玉英; 杨波; 徐勇

    2003-01-01

    As a novel ultrasound diagnostic contrast agent, the preparation, characterization and ultrasound imaging in the body of dog about poly(lactic acid) (PLLA) microcapsules have been studied. The behavior of this kind of contrast agent in the microcirculation was also investigated. Prepared by (water/oil/water) emulsion-solvent evaporation protocol, the PLLA microcapsules with hollow structure can enhance the ultrasound image both in vitro and in vivo, and the enduring time can last as long as 3 h. The microcirculation examination shows that the PLLA microcapsules with a diameter ranging from 2 to 8 μm could pass through the pulmonary capillaries without retention. All the results prove the PLLA microcapsules for potential use for the clinical application.

  17. Biodegradable PLA (polylactic acid) hinged trays keep quality of fresh-cut and cooked spinach.

    Science.gov (United States)

    Botondi, Rinaldo; Bartoloni, Serena; Baccelloni, Simone; Mencarelli, Fabio

    2015-09-01

    This work examines the effects of packaging using two different polymeric trays with hinged lids, polyethylene terephthalate (PET) and polylactic acid (PLA), on fresh-cut and cooked spinach (Spinacia oleracea). Samples were stored in a cold room for 16 days at 4 °C. Chemical (total pigments, total polyphenols, ascorbic acid, antioxidant activity), physical (water activity), technological (colour evaluation), sensorial (aroma, visual appearance and water accumulation) and microbial (total aerobic mesophilic and psychrotrophic counts) parameters were tested. Both polymeric trays maintained the overall quality of fresh spinach for 6 days but spinach stored in PLA trays maintained its flavour longer. A significant increase in total polyphenols, antiradical activity, total carotenoids as well as a decrease in ascorbic acid in fresh spinach was observed in the first 3 days of storage in both samples. Unfortunately, the PLA package accumulated condensed water. The total microbial load of fresh-cut spinach reached about 6.3-7.3 log CFU g(-1) within 8 days. Cooked spinach packed in PLA and PET polymeric hinged trays showed the same behaviour as fresh spinach in terms of quality and shelf life. In conclusion, PLA plastic hinged trays can be used for packaging fresh-cut and cooked cut spinach, but the problem of condensed water must be solved.

  18. [Experimental assessment of biodegradable polyglycolic and polylactic acid polymers for medical use].

    Science.gov (United States)

    Kulakov, A A; Grigor'ian, A S; Arkhipov, A V

    2013-01-01

    Interrelations of biodegradable poliglicolic and polilactic acid polymers in various proportions implanted in standardized bone defects were evaluated in animal model with 40 Wister line rats. During 10 month follow-up period bone capsule surrounded all implants, but timing of bone formation and bone quality varied significantly being optimal in LactoSorb group. Destructive features of polymers were also seen in implant-bone contact area defined as inflammation, fibrous tissue formation and cell dystrophy. PMID:24300698

  19. Biodegradable Poly(Lactic Acid/Multiwalled Carbon Nanotube Nanocomposite Fabrication Using Casting And Hot Press Techniques

    Directory of Open Access Journals (Sweden)

    Park S.G.

    2015-06-01

    Full Text Available Biodegradable advanced polymer composites have recently received a large amount of attention. The present study aimed to design poly(lactic acid multiwalled carbon nanotube nanocomposites (PLA/MWCNTs using a simple fabrication technique. A PLA sheet was first dissolved in dichloromethane, and MWCNTs were subsequently added at various concentrations (0.5, 1.5 and 5% while applying shear strain stirring to achieve dispersion of carbon nanotubes (CNTs. These solutions were then molded and a hot press was used to generate sheets free of voids with entrapped solvent. The prepared samples were characterized using field emission scanning electron microscopy (FE-SEM, x-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, and thermogravimetric analysis (TGA. Our data showed composite samples free of defects and voids, indicating that the hot press is capable of generating sufficiently compact polymer matrices. Additionally, TGA and FTIR showed significant bonding interactions between the PLA matrix and the nano-fillers. Collectively, our results suggest that incorporation of CNTs as nano-fillers into biodegradable polymers may have multiple applications in many different sectors.

  20. Softened and flexible biodegradable poly(lactic acid) and its electromechanical properties for actuator application.

    Science.gov (United States)

    Thummarungsan, Natlita; Pattavarakorn, Datchanee; Sirivat, Anuvat

    2016-12-01

    Poly (lactic acid) (PLA) is a biodegradable polymer with high stiffness presenting a limitation for using in actuator applications. Adding a plasticizer is one way to solve this problem to enhance flexibility and improve electromechanical properties of pristine PLA. In this work, the PLA films were prepared via a simple solvent casting method. The influences of plasticizer type and electric field strength on electromechanical behavior of PLA films were investigated by the melt rheometer and bending measurement. For the PLA films filled with dibutyl phthalate (DBP), the storage modulus, G', immediately increased towards its steady state and rapidly recovered to its original value with and without electric field, respectively, which can be referred to a reversible system. On the other hand, the PLA film with Tween 20 processed the highest ∆G׳/G׳0 of 1.34 due to the available amount of polarized groups. In the bending measurement, the dielectrophoresis forces of plasticized PLA films were found to increase with increasing electric field where the deflections occurred towards anode side as the polarized groups generated negative charges. The DBP_PLA1.5D film exhibited the greatest bending and dielectrophoresis force. Thus, the biodegradable PLA along with DBP combine to have a great potential towards actuator application. PMID:27479892

  1. Biodegradation of thermoplastic starch and its blends with poly(lactic acid) and polyethylene: influence of morphology

    Science.gov (United States)

    The room temperature mineralization of thermoplastic starch (TPS) with a high glycerol content and its blends with low-density polyethylene (LDPE) and polylactic acid (PLA) are examined under controlled degradation conditions. These results are correlated with the morphologies and continuity behavio...

  2. Biodegradation of poly(lactic acid), poly(hydroxybutyrate-co-hydroxyvalerate), poly(butylene succinate) and poly(butylene adipate-co-terephthalate) under anaerobic and oxygen limited thermophilic conditions

    OpenAIRE

    Jutakan Boonmee; Charnwit Kositanont; Thanawadee Leejarkpai

    2016-01-01

    In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid) (PLA), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), poly(butylene succinate) (PBS), and poly(butylene adipate-co-terephthalate) (PBAT) were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of b...

  3. Usefulness of biodegradable stents constructed of poly-/-lactic acid monofilaments in patients with benign esophageal stenosis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To report 13 patients with benign esophageal stenosis treated with the biodegradable stent.METHODS: We developed a Ultraflex-type stent by knitting poly-l-lactic acid monofilaments.RESULTS: Two cases were esophageal stenosis caused by drinking of caustic liquid, 4 cases were due to surgical resection of esophageal cancers, and 7 cases were patients with esophageal cancer who received the preventive placement of biodegradable stents for postendoscopic mucosal dissection (ESD) stenosis. The preventive placement was performed within 2 to 3 d after ESD. In 10 of the 13 cases, spontaneous migration of the stents occurred between 10 to 21 d after placement. In these cases, the migrated stents were excreted with the feces, and no obstructive complications were experienced. In 3 cases, the stents remained at the proper location on d 21 after placement. No symptoms of re-stenosis were observed within the follow-up period of 7 mo to 2 years. Further treatment with balloon dilatation or replacement of the biodegradable stent was not required.CONCLUSION: Biodegradable stents were useful for the treatment of benign esophageal stenosis, particularly for the prevention of post-ESD stenosis.

  4. Green chemical synthesis of poly(lactic acid) based biodegradable polymers%聚乳酸降解材料的绿色化学合成

    Institute of Scientific and Technical Information of China (English)

    许文殊; 罗祥林

    2011-01-01

    背景:聚乳酸具有良好的生物相容性和生物降解性,广泛应用于药物缓释、手术缝合线、组织工程支架及骨修复材料等生物医用领域.但其常规合成方法需使用溶剂,生产效率较低且成本较高.目的:对非溶剂的绿色化学方法-乳酸熔融缩聚/二异氰酸酯熔融扩链,合成聚乳酸降解材料的研究进展进行综述.方法:应用计算机检索SCI-Expanded数据库(1995-01/2010-06),以"Poly(lactic acid),diisocyanate"为检索词;应用计算机检索中国期刊网络出版总库(1999-01/2010-06),以"聚乳酸,异氰酸酯"为检索词.共收集130篇关于乳酸熔融缩聚/二异氰酸酯熔融扩链的文献,中文39篇,英文91篇.排除发表内容重复、实验结果较差的文献,共32篇文献符合标准被纳入.结果与结论:采用非溶剂的绿色化学方法-乳酸熔融缩聚/二异氰酸酯熔融扩链,通过改变异氰酸酯和预聚物的种类和比例,就可以制备具有不同相对分子质量和性能的可降解聚乳酸基聚氨酯材料,有望在生物医用领域和日常生活中取得实际的应用.%BACKGROUND: Poly(lactic acid) has excellent biocompatibility and biodegradability, thus it has been widely used in many biomedical fields, such as drug delayed release, surgical suture, tissue engineering scaffold and bone substitutes. Routine synthesis requires the use of solvent, showing low production efficacy and high cost.OBJECTIVE: Non-solvent green chemical synthesis of poly(lactic acid) based biodegradable materials via direct condensation polymerization and chain extension in melt state were reviewed.METHODS: A computer-based online search of SCI-Expanded database (1995-01/2010-06) and China Academic Journal Network Publishing Database was performed for related articles with the key words of "poly (lactic acid), diisocyanate" in English and in Chinese. A total of 130 articles regarding the lactic acid polycondensation/diisocyanate chain extension in melt

  5. Melt Free-Radical Grafting of Maleic Anhydride onto Biodegradable Poly(lactic acid by Using Styrene as A Comonomer

    Directory of Open Access Journals (Sweden)

    Piming Ma

    2014-05-01

    Full Text Available Maleic anhydride (MA was grafted onto poly(lactic acid (PLA in the presence of styrene (St by using a free-radical grafting methodology. The grafting degree (Dg of MA was increased from 0.65 wt % to 1.1 wt % with the St/MA ratio up to 2/1, where the grafting efficiency (Eg of MA was 27%. However, both Dg and Eg were decreased with further increasing of the St/MA ratio to 4/1. The Dg of MA increased with MA concentration and showed a maximum at 180 °C in the temperature range of 165 °C–190 °C. The grafting mechanisms of MA in the presence of St are analyzed based on titration, thermogravimetric analysis and infrared results, i.e., MA is grafted onto PLA chains via single monomers and a charge-transfer-complex (CTC at St/MA ratios of ≤ 1/1, while dominantly via St-co-MA oligomers at St/MA ratios of around 2/1. Copolymerization rather than grafting of St and MA occurs at St/MA ratios of around 4/1. The thermal stability of PLA was compromised to a certain extent by the grafting of MA, resulting in reductions in the decomposition temperature (Td-5% and molecular weight of the PLA. In addition, the crystallization and melting temperatures of the PLA were slightly reduced after the grafting.

  6. Effect of Modification on Properties of Wood Fiber/Polylactic Acid Biodegradable Composites%改性处理对木纤维/聚乳酸生物可降解复合材料性能的影响

    Institute of Scientific and Technical Information of China (English)

    李辉; 李新功; 吴义强

    2011-01-01

    分别用硬脂酸和钛酸酯对木纤维进行改性,用注塑成型工艺制备术纤维/聚乳酸可生物降解复合材料.研究了改性剂用量对复合材料力学性能及生物降解性能的影响.结果表明:改性剂对木纤维进行处理后,复台材料的拉伸强度与冲击强度得到明显提高;钛酸酯偶联剂的改性效果优于硬脂酸.硬脂酸和钛酸酯改性剂一定程度上都可以改善复合材料的生物降解性能.%Wood fiber/polylactic acid biodegradable composites was prepared with polylactic acid and wood fibers modified with stearine acid and titanate modifiers by injection molding process. Effect of the modification agent on mechanical properties and Biodegradability of composites was studied. The results show that: after modification for wood fibers, the tensile strength and impact strength of composites are significantly improved; and the modification effect of titanate coupling agent is better than that of stearine acid. To some extent, stearic acid and titanate modifier can improve the biodegradability of composites.

  7. 组织工程用聚乳酸系生物可降解高分子材料修饰研究进展%Development in Biodegradable Polylactic Acid Used in Tissue Engineering

    Institute of Scientific and Technical Information of China (English)

    姚芳莲; 孟继红; 毛君淑; 姚康德

    2001-01-01

      Development in biodegradable modified polylactic acid materials and their uses in tissue engineering were reviewed in this paper. The modified methods include block copolymerization, graft copolymerization, surface modifying and combination. Subsequently, a prospect for the development tissue engineering application of decorated polylactic acid has been predicted.%  对近年来聚乳酸系生物降解性高分子材料的修饰改性及其在组织工程研究中的应用作了综述,主要包括聚乳酸的嵌段共聚物、接枝共聚物、表面修饰及复合材料,预示了该类材料在组织工程领域中的研究开发前景。

  8. Tailoring of catalytic routes towards high performance polylactic acid polymers.

    OpenAIRE

    Dusselier, Michiel

    2013-01-01

    Renewable polymers offer a promising alternative for certain fossil fuel derived plastics and harness potential as well in specialty applications. One of the top 3 polymers in this respect is polylactic acid (PLA). Next to its renewable origin Â# sugars, abundantly encountered in food crops but also in non-edible cellulose Â# PLA is biocompatible and biodegradable. These unique features render this polymer suitable for many custom applications, for instance in medicine (prostheses, drug deliv...

  9. 可生物降解聚乳酸并捻长丝纱的制备及性能研究%Study on Preparation and Properties of Biodegradable Polylactic Acid Doubling and Twisting Filament Yarn

    Institute of Scientific and Technical Information of China (English)

    吴改红; 刘淑强; 荆云娟; 许巧丽

    2013-01-01

    以可生物降解的聚乳酸长丝为原料,经并捻、热定形加工制备了聚乳酸并捻长丝纱,优化并捻工艺和热定形工艺,并对纱线的结构和性能进行了测试分析.结果表明:并捻工序的最优捻度为300捻/m,聚乳酸并捻长丝纱比原丝断裂强度降低,断裂伸长率增大,且随捻度的增大,纱线的断裂强度逐渐降低,断裂伸长率升高;热定形工序的最佳热定形温度为80℃,热定形时间为1h;聚乳酸并捻长丝纱表面光洁,光泽好,纱为股线结构,比原丝束断裂强度下降9.7%,断裂伸长率提高7.6%.聚乳酸并捻长丝纱提高了长丝纱的集束性、耐磨性,利于以后的织造工艺.%This paper prepares polylactic acid doubling and twisting filament yarn through doubling and twisting and heat setting with biodegradable polylactic acid filament as raw material, optimizes doubling and twisting process and heat setting process and tests and analyzes the structure and property of yarn. The result shows that the optimal degree of twist of doubling and twisting process is 300 twists/m; compared to protofilament, polylactic acid doubling and twisting filament yarn has a reduced breaking strength and increased elongation at break; with the increase of degree of twist, the breaking strength of yarn gradually decreases and the elongation at break increases; the optimal heat setting temperature of heat setting process is 80 ℃ and heat setting time is 1 h; polylactic acid doubling and twisting filament yarn has a bright, clear and glossy surface; the yarn has a compound yarn structure and its breaking strength reduces by 9. 7% and elongation at break increases by 7. 6% compared to protofilament tows. Polylactic acid doubling and twisting filament yarn improves the bundling and abrasive resistance of filament yarn and is conducive to future weaving process.

  10. Sandwich-Architectured Poly(lactic acid)-Graphene Composite Food Packaging Films

    NARCIS (Netherlands)

    Goh, Kunli; Heising, Jenneke K.; Yuan, Yang; Karahan, Huseyin E.; Wei, Li; Zhai, Shengli; Koh, Jia Xuan; Htin, Nanda M.; Zhang, Feimo; Wang, Rong; Fane, Anthony G.; Dekker, Matthijs; Dehghani, Fariba; Chen, Yuan

    2016-01-01

    Biodegradable food packaging promises a more sustainable future. Among the many different biopolymers used, poly(lactic acid) (PLA) possesses the good mechanical property and cost-effectiveness necessary of a biodegradable food packaging. However, PLA food packaging suffers from poor water vapor

  11. Biodegradation of poly(lactic acid, poly(hydroxybutyrate-co-hydroxyvalerate, poly(butylene succinate and poly(butylene adipate-co-terephthalate under anaerobic and oxygen limited thermophilic conditions

    Directory of Open Access Journals (Sweden)

    Jutakan Boonmee

    2016-01-01

    Full Text Available In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid (PLA, poly(hydroxybutyrate-co-hydroxyvalerate (PHBV, poly(butylene succinate (PBS, and poly(butylene adipate-co-terephthalate (PBAT were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of biodegradation after 75 days was investigated by weight loss determination, visual examination, and surface appearance by scanning electronic microscopy (SEM. Under both anaerobic and oxygen limited conditions, the complete degradation (100% weight loss was found only in PHBV after 75 days. The plastic degradations were ranked in the order of PHBV> PLA> PBS> PBAT. The percentage of weight losses were significantly different at p ≤ 0.05. However, for all studied plastics, the degradation under anaerobic and oxygen limited conditions did not significantly different at 95% confidence.

  12. 绿色塑料聚乳酸的关键技术研发与产业化应用%Key Technology R & D and Industrial Applications of Biodegradable Plastics Polylactic Acid

    Institute of Scientific and Technical Information of China (English)

    陈学思

    2015-01-01

    As a new bio-based green plastic, polylactic acid (PLA) can be widely used in various ifelds. It can provide strong material support to solve environmental pollution and oil dependence. For the current existence of key scientiifc and technical problems in polylactic acid industry, CAS Changchun Institute of Applied Chemistry carry out innovative projects to promote development and application of key technologies of biological polylactic acid green plastic industrialization. It makes a breakthrough of a series of key technical problems on L-lactic acid, lactic acid oligomerization break, cracking, reifning and lactide ring-opening polymerization and makes a series of innovative achievements. It achieved the world's second large-scale production and application of PLA after the US and accelerate the polylactic acid as the leading biodegradable plastics industry development. This article reviews the importance of polylactic key technology development and industrialization projects and the good results which has achieved. It put forward some suggestions of polylactic acid for industrial development in China.%聚乳酸(PLA)作为一种新型生物基绿色塑料,能够广泛应用于多种领域,为解决环境污染和石油依赖等问题提供有力的材料支撑。中国科学院长春应用化学研究所针对当前聚乳酸产业化存在的关键科学和技术性难题,开展了生物基聚乳酸绿色塑料产业化关键技术的创新性研发及应用推广项目,从L-乳酸出发,突破了乳酸低聚、裂解、丙交酯精制和开环聚合等一系列关键技术问题,取得了一系列创新性成果,在世界上继美国Nature Works后第二个实现了PLA规模化生产和应用,加速推动了以聚乳酸为龙头的生物可降解塑料行业的发展。本文综述了聚乳酸关键技术研发与产业化项目的重要意义,已取得的阶段性成果,并针对聚乳酸产业化在我国的发展提出了许多对策建议。

  13. Preclinical in vivo Performance of Novel Biodegradable, Electrospun Poly(lactic acid and Poly(lactic-co-glycolic acid Nanocomposites: A Review

    Directory of Open Access Journals (Sweden)

    Claudia Holderegger

    2015-08-01

    Full Text Available Bone substitute materials have witnessed tremendous development over the past decades and autogenous bone may still be considered the gold standard for many clinicians and clinical approaches in order to rebuild and restore bone defects. However, a plethora of novel xenogenic and synthetic bone substitute materials have been introduced in recent years in the field of bone regeneration. As the development of bone is actually a calcification process within a collagen fiber arrangement, the use of scaffolds in the formation of fibers may offer some advantages, along with additional handling characteristics. This review focuses on material characteristics and degradation behavior of electrospun biodegradable polyester scaffolds. Furthermore, we concentrated on the preclinical in vivo performance with regard to bone regeneration in preclinical studies. The major findings are as follows: Scaffold composition and architecture determine its biological behavior and degradation characteristics; The incorporation of inorganic substances and/or organic substances within composite scaffolds enhances new bone formation; L-poly(lactic acid and poly(lactic-co-glycolic acid composite scaffolds, especially when combined with basic substances like hydroxyapatite, tricalcium phosphate or demineralized bone powder, seem not to induce inflammatory tissue reactions in vivo.

  14. Research Progress in Completely Biodegradable Poly(Lactic Acid) Blends%完全生物降解聚乳酸共混复合材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    陈卫丰; 居学成; 翟茂林

    2011-01-01

    Poly(lactic acid)(PLA) is a kind of aliphatic polycarbonate made from lactic acid. It exhibits good biocompatibility, biodegradability, and mechanical properties. Due to some disadvantages such as slow crystallization, high shrinkage, poor dimensional stability, weak durability and brittleness, the application of PLA is limited. Recently, much attention has been paid to modify and reinforce PLA, especially to blend PLA with other materials to prepare completely biodegradable blends or composites. Many organic or inorganic fillers and biodegradable polymers are used to blend with PLA. This paper fully introduced the completely biodegradable PLA blends and composites in recent years, and summarized the research progress.%聚乳酸(PLA)是由乳酸直接缩聚或丙交酯开环聚合制得的脂肪族聚酯,具有生物相容性、生物降解性和良好的力学性能.但是,由于纯PLA树脂的结晶速率慢、制品收缩率大、本身质脆等缺点,需要各种无机或有机材料对其进行共混改性.制备可完全生物降解的PLA共混复合材料,成为目前研究热点.文中全面介绍了近年来可以完全生物降解的PLA共混复合体系,综述了其最新研究进展.

  15. Process for polylactic acid production using monascus

    NARCIS (Netherlands)

    Weusthuis, R.A.; Wolbert, E.J.H.; Springer, J.; Oost, van der J.; Eggink, G.

    2012-01-01

    A process for producing polylactic acid (PLA) comprising the steps: fermenting in a fermentation vessel a micro-organism of the genus Monascusin a medium at a pH less than or equal to 5 under conditions which produce lactic acid into the medium, converting the lacticacid produced into lactide, and p

  16. ERYTHROMYCIN POLYLACTIC ACID MICROSPHERES FOR LUNG TARGETING

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    AIM: To prepare polylactic acid microspheres of Erythromycin for Lung targeting.METHEDS: The orthogonal test design was used to optimize the technology,of preparation. Thecharacter of the microspheres, drug release in vitro, stability and tissue distribution were examinedRESULTS: The Erythromycin polylactic acid microspheres was regular in its morphology. Drugwas enveloped in microspheres but not physically mixed with PDLLA. The average particle size was11.65μn with over 94% of the microspheres being in the range of 5~20trn; The drug loading andthe incorporation efciency were 18% and 60% respectively. The microspheres were stable for threemonth at 4 ℃ and room temperature. The in vitro release properties could be expressed by theHiguchi's equation: y = 28.067 + 3.8515t11/2 (r = 0.9834). Comparing with injection, the drug inmicrospheres was more concentrated in lung tissue. CONCLUSION: Erythromycin polylactic acidmicrospheres showed significant sustained release and lung targeting.

  17. Effect of gamma ray on poly(lactic acid)/poly(vinyl acetate-co-vinyl alcohol) blends as biodegradable food packaging films

    International Nuclear Information System (INIS)

    Poly(lactic acid) (PLA)/poly(vinyl acetate-co-vinyl alcohol) [P(VAc-co-VA)] blends as new transparent film packaging materials were prepared at various blend compositions and different vinyl alcohol contents. The blends and pure PLA were irradiated by gamma rays to investigate the extent of changes in the packaging material during gamma ray sterilization process. The miscibility of the blends was dependent on the blend composition and vinyl alcohol content; gamma irradiation had little effect on the extent of miscibility. The glass transition temperature of pure PLA and PLA/P(VAc-co-VA) miscible blends reduced after irradiation. On the other hand in PLA/P(VAc-co-VA) immiscible blends, while the glass transition temperature of the PLA phase decreased; that of the copolymer phase slightly increased. The reduction in the glass transition was about 10 percent for samples irradiated with 50 kGy indicating dominance of chain scission of PLA molecules at high irradiation dose. The latter was verified by drop in mechanical properties of pure PLA after exposing to gamma irradiation at 50 kGy. Blending of PLA with the copolymer P(VAc-co-VA) compensated greatly the adverse effects of irradiation on PLA. The oxygen-barrier property of the blend was superior to the neat PLA and remained almost intact with irradiation. The un-irradiated and irradiated blends had excellent transparency. Gamma ray doses used for sterilization purposes are usually less than 20 kGy. It was shown that gamma irradiation at 20 kGy had no or little adverse effects on PLA/P(VAc-co-VA) blends mechanical and gas barrier properties. - Highlights: • Poly(lactic acid)/poly(vinyl acetate-co-vinyl alcohol) blends were prepared as new packaging film. • The blends are superior to PLA in oxygen gas barrier property. • The blends are suitable for gamma ray sterilization and maintain useful mechanical properties. • The blends are perfectly transparent

  18. Poly(lactic acid) and Osage Orange Wood Fiber Composites for Agricultural Mulch Films

    Science.gov (United States)

    Osage orange wood(OO)was combined with poly(lactic acid)(PLA)to form a polymer composite intended for use as an agricultural mulch film. The PLA-OO mechanical properties were comparable to existing mulch film products and had the advantage of being completely biodegradable through a single growing ...

  19. GREEN COMPOSITES OF POLY(LACTIC ACID) AND OILSEED CO-PRODUCTS

    Science.gov (United States)

    Poly(lactic acid)(PLA) is a biodegradable plastic made from renewable resources and has similar mechanical properties to polypropylene. PLA is more expensive than petroleum-based plastics, and the use of low-cost fillers as extenders is desirable. Agricultural co-products (AcP) of oilseed crops we...

  20. POLY(LACTIC ACID) GREEN COMPOSITES USING OILSEED COPRODUCTS AS FILLERS

    Science.gov (United States)

    Poly(lactic acid), PLA, is a biodegradable polymer made from renewable resources with similar mechanical properties to polypropylene. PLA is more expensive than petroleum-based plastics, and the use of low-cost fillers as extenders is desirable. Agricultural co-products of the alternative oilseed ...

  1. Effect of gamma ray on poly(lactic acid)/poly(vinyl acetate-co-vinyl alcohol) blends as biodegradable food packaging films

    Science.gov (United States)

    Razavi, Seyed Mohammad; Dadbin, Susan; Frounchi, Masoud

    2014-03-01

    Poly(lactic acid) (PLA)/poly(vinyl acetate-co-vinyl alcohol) [P(VAc-co-VA)] blends as new transparent film packaging materials were prepared at various blend compositions and different vinyl alcohol contents. The blends and pure PLA were irradiated by gamma rays to investigate the extent of changes in the packaging material during gamma ray sterilization process. The miscibility of the blends was dependent on the blend composition and vinyl alcohol content; gamma irradiation had little effect on the extent of miscibility. The glass transition temperature of pure PLA and PLA/P(VAc-co-VA) miscible blends reduced after irradiation. On the other hand in PLA/P(VAc-co-VA) immiscible blends, while the glass transition temperature of the PLA phase decreased; that of the copolymer phase slightly increased. The reduction in the glass transition was about 10 percent for samples irradiated with 50 kGy indicating dominance of chain scission of PLA molecules at high irradiation dose. The latter was verified by drop in mechanical properties of pure PLA after exposing to gamma irradiation at 50 kGy. Blending of PLA with the copolymer P(VAc-co-VA) compensated greatly the adverse effects of irradiation on PLA. The oxygen-barrier property of the blend was superior to the neat PLA and remained almost intact with irradiation. The un-irradiated and irradiated blends had excellent transparency. Gamma ray doses used for sterilization purposes are usually less than 20 kGy. It was shown that gamma irradiation at 20 kGy had no or little adverse effects on PLA/P(VAc-co-VA) blends mechanical and gas barrier properties.

  2. Utilization of a Biodegradable Mulch Sheet Produced from Poly(Lactic Acid/Ecoflex®/Modified Starch in Mandarin Orange Groves

    Directory of Open Access Journals (Sweden)

    Yasukatsu Maeda

    2009-08-01

    Full Text Available We have developed a mulch sheet made by inflation molding of PLA, Ecoflex® and modified starch, which all have different biodegradabilities. A field test of use as an agricultural mulch sheet for mandarin oranges was carried out over two years. The mechanical properties of the mulch sheet were weakened with time during the field test, but the quality of the mandarin oranges increased, a result of the controlled degradation of the sheet. The most degradable modified starch degraded first, allowing control of the moisture on the soil. Accelerator mass spectroscopy was used for evaluation of the biomass carbon ratio. The biomass carbon ratio decreased by degradation of the biobased materials, PLA and modified starch in the mulch sheet.

  3. ERYTHROMYCIN POLYLACTIC ACID MICROSPHERES FOR LUNG TARGETING

    Institute of Scientific and Technical Information of China (English)

    YANGFan; YANBing; 等

    2002-01-01

    AIM:To prepare polylactiv acid microspheres of Erythromycin for Lung targeting.METHEDS:The orthogonal test design was used to optimize the technology of preparation.The character of the microspheres,drug release in vitro,stabiligy and tissue distribution were examined. RESULTS:The Erythromycin polylatic acid microspheres was regular in its morphology.Drug was enveloped in microspheres but not physically mixed with PDLLA.The average particle size was 11.65μm with over 94% of the microspheres being in the range of 5-20μm;The drug loading and the incorporation efficiency were 18% and 60% respectively.The microspheres were stable for three month at 4℃ and room temperature.The in vitro release properties could be expressed by the Higuchi′s equation:y=28.067+3.8515t1/2(r=0.9834).Comparing with injection,the drug in microspheres was more concentrated in lung tissue.CONLUSION:Erythromycin polylactic acid microspheres showed significant sustained release and lung targeting.

  4. Lactide Synthesis and Chirality Control for Polylactic acid Production.

    Science.gov (United States)

    Van Wouwe, Pieter; Dusselier, Michiel; Vanleeuw, Evelien; Sels, Bert

    2016-05-10

    Polylactic acid (PLA) is a very promising biodegradable, renewable, and biocompatible polymer. Aside from its production, its application field is also increasing, with use not only in commodity applications but also as durables and in biomedicine. In the current PLA production scheme, the most expensive part is not the polymerization itself but obtaining the building blocks lactic acid (LA) and lactide, the actual cyclic monomer for polymerization. Although the synthesis of LA and the polymerization have been studied systematically, reports of lactide synthesis are scarce. Most lactide synthesis methods are described in patent literature, and current energy-intensive, aselective industrial processes are based on archaic scientific literature. This Review, therefore, highlights new methods with a technical comparison and description of the different approaches. Water-removal methodologies are compared, as this is a crucial factor in PLA production. Apart from the synthesis of lactide, this Review also emphasizes the use of chemically produced racemic lactic acid (esters) as a starting point in the PLA production scheme. Stereochemically tailored PLA can be produced according to such a strategy, giving access to various polymer properties.

  5. Heat capacity of poly(lactic acid)

    International Nuclear Information System (INIS)

    The heat capacity of poly(lactic acid) (PLA) is reported from T=(5 to 600) K as obtained by differential scanning calorimetry (d.s.c.) and adiabatic calorimetry. The heat capacity of solid PLA is linked to its group vibrational spectrum and the skeletal vibrations, the latter being described by a Tarasov equation with Θ1=574 K, Θ2=Θ3=52 K, and nine skeletal vibrations. The calculated and experimental heat capacities agree to ±3% between T=(5 and 300) K. The experimental heat capacity of liquid PLA can be expressed by Cp(liquid)=(120.17+0.076T) J · K-1 · mol-1 and has been compared to the ATHAS Data Bank, using contributions of other polymers with the same constituent groups. The glass transition temperature of amorphous PLA occurs at T=332.5 K with a change in heat capacity of 43.8 J · K-1 · mol-1. Depending on thermal history, semi-crystalline PLA has a melting endotherm between T=(418 and 432) K with variable heats of fusion. For 100% crystalline PLA, the heat of fusion is estimated to be (6.55 ± 0.02) kJ · mol-1 at T=480 K. With these results, the enthalpy, entropy, and Gibbs function of crystalline and amorphous PLA were obtained. For semi-crystalline samples, one can check changes of crystallinity with temperature and judge the presence of rigid-amorphous fractions

  6. Biobased additive plasticizing Polylactic acid (PLA

    Directory of Open Access Journals (Sweden)

    Mounira Maiza

    2015-12-01

    Full Text Available Polylactic acid (PLA is an attractive candidate for replacing petrochemical polymers because it is from renewable resources. In this study, a specific PLA 2002D was melt-mixed with two plasticizers: triethyl citrate (TEC and acetyl tributyl citrate (ATBC. The plasticized PLA with various concentrations were analyzed by differential scanning calorimetry (DSC, dynamic mechanical analysis (DMA, melt flow index (MFI, thermogravimetric analysis (TGA, X-ray diffraction (XRD, UV-Visible spectroscopy and plasticizer migration test. Differential scanning calorimetry demonstrated that the addition of TEC and ATBC resulted in a decrease in glass transition temperature (Tg, and the reduction was the largest with the plasticizer having the lowest molecular weight (TEC. Plasticizing effect was also shown by decrease in the dynamic storage modulus and viscosity of plasticized mixtures compared to the treated PLA. The TGA results indicated that ATBC and TEC promoted a decrease in thermal stability of the PLA. The X-ray diffraction showed that the PLA have not polymorphic crystalline transition. Analysis by UV-Visible spectroscopy showed that the two plasticizers: ATBC and TEC have no effect on the color change of the films. The weight loss plasticizer with heating time and at 100°C is lesser than at 135 °C. Migration of TEC and ATBC results in cracks and changed color of material. We have concluded that the higher molecular weight of citrate in the studied exhibited a greater plasticizing effect to the PLA.

  7. Mechanical Properties and Water Absorption Behaviour of Durian Rind Cellulose Reinforced Poly(lactic acid Biocomposites

    Directory of Open Access Journals (Sweden)

    Patpen Penjumras

    2015-01-01

    Full Text Available Environmental concerns have resulted in replacing petrochemically derived polymer with biodegradable renewable resource. In this study, mechanical properties and water absorption behaviour of durian rind cellulose reinforced poly(lactic acid biocomposites were investigated. Poly(lactic acid was mixed with 25 and 35 wt. % of durian rind cellulose that was derived from durian consumption wastes. The biocomposties were melt-blended at 165 and 175 °C with 15 min using a Brabender internal mixer followed by a hot compression moulding technique. The results showed that impact strength and modulus of Young increased with increasing of cellulose content but decreased at higher mixing temperature. Water absorption behaviour of biocomposites as function of days was also investigated. It was found that the water absorption amount of biocomposites increased with increasing of cellulose content and exposure time.    

  8. Biodegradation of cyanuric acid.

    Science.gov (United States)

    Saldick, J

    1974-12-01

    Cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved-oxygen level, such as anaerobic activated sludge and sewage, soils, muds, and muddy streams and river waters, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved-oxygen levels. Degradation also proceeds in 3.5% sodium chloride solution. Consequently, there are degradation pathways widely available for breaking down cyanuric acid discharged in domestic effluents. The overall degradation reaction is merely a hydrolysis; CO(2) and ammonia are the initial hydrolytic breakdown products. Since no net oxidation occurs during this breakdown, biodegradation of cyanuric acid exerts no primary biological oxygen demand. However, eventual nitrification of the ammonia released will exert its usual biological oxygen demand.

  9. Preparation and evaluations in vitro of oxaliplatin polylactic acid nanoparticles.

    Science.gov (United States)

    Cui, Zhaoyuan; Sun, Yong; Liu, Xiaohong; Ju, Fang; Chen, Qian; Gao, Wen; Wei, Haitian

    2013-08-01

    The oxaliplatin nanoparticles were prepared with polylactic acid matrix, orthogonal test was applied to optimize the prescriptions, and the qualities of oxaliplatin nanoparticles were characterized by the shape, particle size, encapsulation efficiency (EE), and drug loading (DL). Oxaliplatin nanoparticle was prepared by solution replacement method. The formation of 0.25% Tween80, DMF-water 1:8 (v/v), oxaliplatin-polylactic acid 1:5 (w/w), and 20 mg/ml polylactic acid showed the suitable EE (17.4 ± 0.47%), DL (3.52 ± 0.07%). We observed the shape of oxaliplatin nanoparticles through SEM. The average size of the particles was 120.5 ± 8.7 nm, which was detected by N5 submicron particle size analyzer.

  10. Synthesis and Characterization of Cross-linked Poly (β-Cyclodextin) Graft Poly(lactic acid) through Direct Polycondensation

    Institute of Scientific and Technical Information of China (English)

    Z.L.Ren; D.D.Lu; Z.Q.Lei

    2007-01-01

    1 Results Polylactide or polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA) have been utilized as bioabsorbable materials in the medical and pharmaceutical fields due to their biodegradable and biocompatible properties[1].However,due to its hydrophobicity and free carboxylic group,PLA or PLGA was not suitable for use to encapsulate the protein.Recently,poly (ε-caprolactone) and poly (D,L-lactide) were respectively grafted onto hydrophilic dextrin and gelatin to obtain the amphiphilic biodeg...

  11. Polylactic Acid Maybe Hope for Solving White Pollution

    Institute of Scientific and Technical Information of China (English)

    Xu Dan

    2007-01-01

    @@ As the pollution problem has aroused more and more attention, greater efforts have been made in developing degradable biological materials without environmental pollution to replace oil-based traditional plastics being used in great quantities today. Among numerous kinds of degradable polymers, polylactic acid has become the 'green' environmental friendly material with the brightest development prospect.

  12. GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

    Science.gov (United States)

    AbstractThe need for the development of polymeric materials based on renewable resources has led to the development of poly(lactic acid) (PLA) which is being produced from a feedstock of corn rather than petroleum. The present study examines the permeation of nitrogen...

  13. Polylactic Acid-Lemongrass Essential Oil Nanocapsules with Antimicrobial Properties.

    Science.gov (United States)

    Liakos, Ioannis L; Grumezescu, Alexandru Mihai; Holban, Alina Maria; Florin, Iordache; D'Autilia, Francesca; Carzino, Riccardo; Bianchini, Paolo; Athanassiou, Athanassia

    2016-07-07

    Polylactic acid was combined with lemongrass essential oil (EO) to produce functional nanocapsules (NCs). The obtained polylactic acid nanoparticles showed antimicrobial activity both with and without the presence of lemongrass oil; however, the presence of EO improved the activity of the NCs. The presence of lemongrass assisted the formation of well-separated NCs and also provided enhanced antimicrobial properties, since lemongrass is known for its antimicrobial character. Fluorescence microscopy was used to optically observe the nanoparticles and NCs and revealed the attachment of lemongrass oil with the polylactic acid NCs. Dynamic light scattering was used to determine their size. UV absorption was used to determine the exact amount of lemongrass oil found in the polylactic acid-lemongrass oil NCs, which was important for understanding the minimum inhibitory concentration for the antimicrobial experiments. A series of clinically important microbial species were used in the study and the obtained NCs proved to have very good antimicrobial properties against all tested strains. Such NCs can be used for the design of ecological strategies, based on natural alternatives, which may be efficient against severe infections, including those that involve resistant pathogens and biofilms or those with difficult to reach localization.

  14. Effect of polylactic acid crystallinity on its electret properties

    Science.gov (United States)

    Guzhova, A. A.; Galikhanov, M. F.; Kuznetsova, N. V.; Petrov, V. A.; Khairullin, R. Z.

    2016-09-01

    Electret properties of the polylactic acid films with different degree of crystallinity due to different cooling and annealing conditions were studied. Samples with the higher degree of crystallinity showed more stable electret characteristics resulting from amorphous-crystalline interface boundary growth and capturing bigger amount of injected charge carriers by volume energy traps.

  15. [Study on preparation process of artesunate polylactic acid microspheres].

    Science.gov (United States)

    Pan, Xu-Wang; Wang, Wei; Fang, Hong-Ying; Wang, Fu-Gen; Cai, Zhao-Bin

    2013-12-01

    This study aims to investigate the preparation process and in vitro release behavior of artesunate polylactic acid microspheres, in order to prepare an artesunate polylactic acid (PLA) administration method suitable for hepatic arterial embolization. With PLA as the material and polyvinyl alcohol (PVA) as the emulsifier, O/W emulsion/solvent evaporation method was adopted to prepare artesunate polylactic acid microspheres, and optimize the preparation process. With drug loading capacity, encapsulation efficiency and particle size as indexes, a single factor analysis was made on PLA concentration, PVA concentration, drug loading ratio and stirring velocity. Through an orthogonal experiment, the optimal processing conditions were determined as follows: PLA concentration was 9. 0% , PVA concentration was 0. 9% , drug loading ratio was 1:2 and stirring velocity was 1 000 r x min(-1). According to the verification of the optimal process, microsphere size, drug loading and entrapment rate of artesunate polylactic acid microspheres were (101.7 +/- 0.37) microm, (30.8 +/- 0.84)%, (53.6 +/- 0.62)%, respectively. The results showed that the optimal process was so reasonable and stable that it could lay foundation for further studies.

  16. Effects of Biomass in Polyethylene or Polylactic Acid Composites

    Science.gov (United States)

    Previous studies have shown that compounding Polyethylene (PE) or Polylactic acid (PLA) with a dairy-based bioplastic resulted in composites with good mechanical properties. In this study, mass ratios of a dairy-protein-based material (DBP) ranging from 0, 5, 10 and 20 wt% replaced equivalent masse...

  17. New Biodegradable Thermoplastic Multiblock Copolymers from Lactic Acid, ε-Caprolactone, Poly(Ethylene Oxide) and Toluene Diisocyanate

    Institute of Scientific and Technical Information of China (English)

    Jen(o) Borda; Sándor Kéki; Ildikó Bodnár; Nóra Németh; Miklós Zsuga

    2005-01-01

    @@ 1Introduction The interest in finding new biodegradable materials for applications in important areas has been motivated by environmental protection aspects. Foremost among the potentially biodegradable and biocompatible polymers, poly(lactic acid) and poly(ε-caprolactone) received considerable attention as their potential application in a wide range of biomedical and pharmaceutical areas was recognized.

  18. The research situation and consumption market analysis of Polylactic acid%聚乳酸研究现状及消费市场分析

    Institute of Scientific and Technical Information of China (English)

    李宪进; 张伟

    2014-01-01

    Polylactic acid is a polymer by polymerization of lactic acid as the main raw materials.Polylactic acid is an ideal green polymer materials,its raw materials are abundant and renewable;no pollution in the produc-tion process,the product is biodegradable.The research status of polylactic acid at home and abroad was mainly in-troduced,the market consumption scale,distribution and development prospect of polylactic acid industry was ana-lyzed.With the people environmental protection consciousness increasing gradually,polylactic acid as biodegrada-ble materials in various fields will be more and more widely.%聚乳酸是以乳酸为主要原料经聚合而成的聚合物,乳酸等原料来源充分且可再生,生产过程无污染,产品可生物降解,是一种理想的绿色高分子材料。主要介绍了聚乳酸国内外研究现状,分析了聚乳酸工业的市场规模、消费分布和发展前景。认为随着人们环保意识逐渐增加,聚乳酸作为生物可降解材料在各领域的应用将越来越广泛。

  19. Technological and economic potential of poly(lactic acid) and lactic acid derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Datta, R.; Tsai, S.P.; Bonsignore, P.; Moon, S.H.; Frank, J.R.

    1993-10-01

    Lactic acid has been an intermediate-volume specialty chemical (world production {approximately}40,000 tons/yr) used in a wide range of food processing and industrial applications. lactic acid h,as the potential of becoming a very large volume, commodity-chemical intermediate produced from renewable carbohydrates for use as feedstocks for biodegradable polymers, oxygenated chemicals, plant growth regulators, environmentally friendly ``green`` solvents, and specially chemical intermediates. In the past, efficient and economical technologies for the recovery and purification of lactic acid from crude fermentation broths and the conversion of tactic acid to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. The development and deployment of novel separations technologies, such as electrodialysis (ED) with bipolar membranes, extractive distillations integrated with fermentation, and chemical conversion, can enable low-cost production with continuous processes in large-scale operations. The use of bipolar ED can virtually eliminate the salt or gypsum waste produced in the current lactic acid processes. In this paper, the recent technical advances in tactic and polylactic acid processes are discussed. The economic potential and manufacturing cost estimates of several products and process options are presented. The technical accomplishments at Argonne National Laboratory (ANL) and the future directions of this program at ANL are discussed.

  20. Crystallization kinetics of poly(lactic acid-talc composites

    Directory of Open Access Journals (Sweden)

    2011-10-01

    Full Text Available The crystallization kinetics of poly(lactic acid / talc composites were determined over a range of 0 to 15 wt% of talc. Talc was found to change the crystallization kinetics. The presence of talc increases the crystallization rate and this increase is related to talc concentration and to crystallization temperature. In order to understand the effect of talc and PLA crystallinity on mechanical properties, dynamic mechanical thermal analyses were performed on poly(lactic acid / talc composites before and after an annealing process. It was demonstrated that the presence of crystals improves thermomechanical properties but in order to achieve good results at high temperatures the reinforcing effect of a filler such as talc is necessary.

  1. Biodegradable Tri-Block Copolymer Poly(lactic acid)-poly(ethylene glycol)-poly(L-lysine)(PLA-PEG-PLL) as a Non-Viral Vector to Enhance Gene Transfection

    OpenAIRE

    Na Zhang; Chunhua Fu; Xiaoli Sun; Donghua Liu; Zaijun Lu; Zhijing Chen

    2011-01-01

    Low cytotoxicity and high gene transfection efficiency are critical issues in designing current non-viral gene delivery vectors. The purpose of the present work was to synthesize the novel biodegradable poly (lactic acid)-poly(ethylene glycol)-poly(L-lysine) (PLA-PEG-PLL) copolymer, and explore its applicability and feasibility as a non-viral vector for gene transport. PLA-PEG-PLL was obtained by the ring-opening polymerization of Lys(Z)-NCA onto amine-terminated NH2-PEG-PLA, then acidolysis ...

  2. Polylactic acid (PLA) synthesis and modifications: a review

    Institute of Scientific and Technical Information of China (English)

    Yanling CHENG; Shaobo DENG; Paul CHEN; Roger RUAN

    2009-01-01

    This article reviews various methods of synthesizing polycondensation and ring-opening polymerization and modifying properties of polylactic acid (PLA), which may be used as biomaterials, such as a drug carrier in a drug delivery system, as a cell scaffold and suture in tissue engineering, and as packaging materials in packaging engineering field. Copolymerization of lactide with other monomers or polymers such as malic acid, polyethylene glycol (PEG), polyglycolic acid (PGA), or dextran, as well as blending polylactide with natural derivatives and other methods of modification are discussed. Surface modifications of PLA-type copolymers, such as surface coating,chemical modification, and plasma treatment are described.

  3. Holographic gratings recorded in poly(lactic acid)/azo-dye films

    Science.gov (United States)

    Cambiasso, Javier; Goyanes, Silvia; Ledesma, Silvia

    2015-09-01

    Diffraction gratings were recorded in biodegradable polymer films of poly(lactic acid) doped with the photoisomerisable azo-dye (Disperse Orange 3). It is shown that the diffraction efficiency of the recorded grating can be improved by 220% via an all-optical treatment. This all-optical treatment consists of a pre-irradiation of the sample with the writing laser beam at high power during a short period of time, preventing damage of the material, followed by a much longer inscription at relatively low power. Furthermore, it is shown that the addition of a small amount of 0.05 wt% of multi-walled carbon nanotubes to the photoresponsive polymer increases the maximum diffraction efficiency as well as the remanent efficiency by 20%. Finally, this last photoresponsive nano-composite is also sensitive to the pre-irradiation treatment.

  4. Influence of lignin on morphology, structure and thermal behavior of polylactic acid-based biocomposites

    Science.gov (United States)

    Canetti, Maurizio; Cacciamani, Adriana; Bertini, Fabio

    2016-05-01

    Polylactic acid (PLA) is a thermoplastic biodegradable polymer that can be made from annually renewable resources. Lignin is a natural amorphous polyphenolic macromolecule inexpensive and easily available. In the present study PLA and acetylated lignin biocomposites were prepared by casting from chloroform solution. PLA can crystallize from the melt in the α and α' forms, depending on the adopted crystallization conditions. The presence of the lignin in the biocomposites can interfere with the crystal formation process. Isothermal crystallizations were performed at different temperatures, the presence of lignin causes an increase of the time of crystallization, while the overall crystallization rate and the spherulite radial growth rate decrease with enhancing the lignin content in the biocomposites.

  5. Proposition of an Accelerated Ageing Method for Natural Fibre/Polylactic Acid Composite

    Science.gov (United States)

    Zandvliet, Clio; Bandyopadhyay, N. R.; Ray, Dipa

    2015-10-01

    Natural fibre composite based on polylactic acid (PLA) composite is of special interest because it is entirely from renewable resources and biodegradable. Some samples of jute/PLA composite and PLA alone made 6 years ago and kept in tropical climate on a shelf shows too fast ageing degradation. In this work, an accelerated ageing method for natural fibres/PLA composite is proposed and tested. Experiment was carried out with jute and flax fibre/PLA composite. The method was compared with the standard ISO 1037-06a. The residual flexural strength after ageing test was compared with the one of common wood-based panels and of real aged samples prepared 6 years ago.

  6. Biodegradable Tri-Block Copolymer Poly(lactic acid-poly(ethylene glycol-poly(L-lysine(PLA-PEG-PLL as a Non-Viral Vector to Enhance Gene Transfection

    Directory of Open Access Journals (Sweden)

    Na Zhang

    2011-02-01

    Full Text Available Low cytotoxicity and high gene transfection efficiency are critical issues in designing current non-viral gene delivery vectors. The purpose of the present work was to synthesize the novel biodegradable poly (lactic acid-poly(ethylene glycol-poly(L-lysine (PLA-PEG-PLL copolymer, and explore its applicability and feasibility as a non-viral vector for gene transport. PLA-PEG-PLL was obtained by the ring-opening polymerization of Lys(Z-NCA onto amine-terminated NH2-PEG-PLA, then acidolysis to remove benzyloxycarbonyl. The tri-block copolymer PLA-PEG-PLL combined the characters of cationic polymer PLL, PLA and PEG: the self-assembled nanoparticles (NPs possessed a PEG loop structure to increase the stability, hydrophobic PLA segments as the core, and the primary ε-amine groups of lysine in PLL to electrostatically interact with negatively charged phosphate groups of DNA to deposit with the PLA core. The physicochemical properties (morphology, particle size and surface charge and the biological properties (protection from nuclease degradation, plasma stability, in vitro cytotoxicity, and in vitro transfection ability in HeLa and HepG2 cells of the gene-loaded PLA-PEG-PLL nanoparticles (PLA-PEG-PLL NPs were evaluated, respectively. Agarose gel electrophoresis assay confirmed that the PLA-PEG-PLL NPs could condense DNA thoroughly and protect DNA from nuclease degradation. Initial experiments showed that PLA-PEG-PLL NPs/DNA complexes exhibited almost no toxicity and higher gene expression (up to 21.64% in HepG2 cells and 31.63% in HeLa cells than PEI/DNA complexes (14.01% and 24.22%. These results revealed that the biodegradable tri-block copolymer PLA-PEG-PLL might be a very attractive candidate as a non-viral vector and might alleviate the drawbacks of the conventional cationic vectors/DNA complexes for gene delivery in vivo.

  7. Continuous microcellular foaming of polylactic acid/natural fiber composites

    Science.gov (United States)

    Diaz-Acosta, Carlos A.

    Poly(lactic acid) (PLA), a biodegradable thermoplastic derived from renewable resources, stands out as a substitute to petroleum-based plastics. In spite of its excellent properties, commercial applications are limited because PLA is more expensive and more brittle than traditional petroleum-based resins. PLA can be blended with cellulosic fibers to reduce material cost. However, the lowered cost comes at the expense of flexibility and impact strength, which can be enhanced through the production of microcellular structures in the composite. Microcellular foaming uses inert gases (e.g., carbon dioxide) as physical blowing agents to make cellular structures with bubble sizes of less than 10 microm and cell-population densities (number of bubbles per unit volume) greater than 109 cells/cm³. These unique characteristics result in a significant increase in toughness and elongation at break (ductility) compared with unfoamed parts because the presence of small bubbles can blunt the crack-tips increasing the energy needed to propagate the crack. Microcellular foams have been produced through a two step batch process. First, large amounts of gas are dissolved in the solid plastic under high pressure (sorption process) to form a single-phase solution. Second, a thermodynamic instability (sudden drop in solubility) triggers cell nucleation and growth as the gas diffuses out of the plastic. Batch production of microcellular PLA has addressed some of the drawbacks of PLA. Unfortunately, the batch foaming process is not likely to be implemented in the industrial production of foams because it is not cost-effective. This study investigated the continuous microcellular foaming process of PLA and PLA/wood-fiber composites. The effects of the processing temperature and material compositions on the melt viscosity, pressure drop rate, and cell-population density were examined in order to understand the nucleation mechanisms in neat and filled PLA foams. The results indicated that

  8. Effect of hydrolysed cellulose nanowhiskers on properties of montmorillonite/polylactic acid nanocomposites.

    Science.gov (United States)

    Arjmandi, Reza; Hassan, Azman; Haafiz, M K M; Zakaria, Zainoha; Islam, Md Saiful

    2016-01-01

    Polylactic acid (PLA) nanocomposites reinforced with hybrid montmorillonite/cellulose nanowhiskers [MMT/CNW(SO4)] were prepared by solution casting. The CNW(SO4) nanofiller was first isolated from microcrystalline cellulose using acid hydrolysis treatment. PLA/MMT/CNW(SO4) hybrid nanocomposites were prepared by the addition of various amounts of CNW(SO4) [1-9 parts per hundred parts of polymer (phr)] into PLA/MMT nanocomposite at 5 phr MMT content, based on highest tensile strength values as reported previously. The biodegradability, thermal, tensile, morphological, water absorption and transparency properties of PLA/MMT/CNW(SO4) hybrid nanocomposites were investigated. The Biodegradability, thermal stability and crystallinity of hybrid nanocomposites increased compared to PLA/MMT nanocomposite and neat PLA. The highest tensile strength of hybrid nanocomposites was obtained by incorporating 1 phr CNW(SO4) [∼ 36 MPa]. Interestingly, the ductility of hybrid nanocomposites increased significantly by 87% at this formulation. The Young's modulus increased linearly with increasing CNW(SO4) content. This is due to the relatively good dispersion of nanofillers in the hybrid nanocomposites, as revealed by transmission electron microscopy. Fourier transform infrared spectroscopy indicated the formation of some polar interactions. In addition, water resistance of the hybrid nanocomposites improved and the visual transparency of neat PLA film did not affect by addition of CNW(SO4). PMID:26592699

  9. Effect of hydrolysed cellulose nanowhiskers on properties of montmorillonite/polylactic acid nanocomposites.

    Science.gov (United States)

    Arjmandi, Reza; Hassan, Azman; Haafiz, M K M; Zakaria, Zainoha; Islam, Md Saiful

    2016-01-01

    Polylactic acid (PLA) nanocomposites reinforced with hybrid montmorillonite/cellulose nanowhiskers [MMT/CNW(SO4)] were prepared by solution casting. The CNW(SO4) nanofiller was first isolated from microcrystalline cellulose using acid hydrolysis treatment. PLA/MMT/CNW(SO4) hybrid nanocomposites were prepared by the addition of various amounts of CNW(SO4) [1-9 parts per hundred parts of polymer (phr)] into PLA/MMT nanocomposite at 5 phr MMT content, based on highest tensile strength values as reported previously. The biodegradability, thermal, tensile, morphological, water absorption and transparency properties of PLA/MMT/CNW(SO4) hybrid nanocomposites were investigated. The Biodegradability, thermal stability and crystallinity of hybrid nanocomposites increased compared to PLA/MMT nanocomposite and neat PLA. The highest tensile strength of hybrid nanocomposites was obtained by incorporating 1 phr CNW(SO4) [∼ 36 MPa]. Interestingly, the ductility of hybrid nanocomposites increased significantly by 87% at this formulation. The Young's modulus increased linearly with increasing CNW(SO4) content. This is due to the relatively good dispersion of nanofillers in the hybrid nanocomposites, as revealed by transmission electron microscopy. Fourier transform infrared spectroscopy indicated the formation of some polar interactions. In addition, water resistance of the hybrid nanocomposites improved and the visual transparency of neat PLA film did not affect by addition of CNW(SO4).

  10. Blending of Polyhydroxybutyrate-co-valerate with Polylactic Acid for Packaging Applications – Reflections on Miscibility and Effects on the Mechanical and Barrier Properties

    OpenAIRE

    Jost, V.; Kopitzky, R.

    2015-01-01

    Biopolymers for packaging applications offer many advantages and are therefore of increasing interest. In order to develop a sustainable alternative for petrochemical-based polymers the biobased and biodegradable polymers, the focus of this work are polyhydroxybutyrate-co-valerate (PHBV) and polylactic acid (PLA) (and copolymers). Blending of these two biopolymers was reviewed under thermodynamic aspects and backed with own results. Additionally, different ways of improving the miscibility we...

  11. Solvent-free preparation of polylactic acid fibers by melt electrospinning using umbrella-like spray head and alleviation of problematic thermal degradation

    OpenAIRE

    Liu Yong; Zhao Fengwen; Zhang Chi; Zhang Jianming; Yang Weimin

    2012-01-01

    Melt electrospinning is an even simpler and safer method compared with the solution electrospinning in the production of ultra-fine fibers. Polylactic acid (PLA) is a biodegradable and resorbable aliphatic ester that has received significant attention in recent years. PLA is easily degradable at high temperature in the process of melt electrospinning. High efficient fibers were made using our designed umbrella-like spray head spinning facility in this work. To find how to alleviate the ...

  12. The Effect of Fiber Bleaching Treatment on the Properties of Poly(lactic acid)/Oil Palm Empty Fruit Bunch Fiber Composites

    OpenAIRE

    Marwah Rayung; Nor Azowa Ibrahim; Norhazlin Zainuddin; Wan Zuhainis Saad; Nur Inani Abdul Razak; Buong Woei Chieng

    2014-01-01

    In this work, biodegradable composites from poly(lactic acid) (PLA) and oil palm empty fruit bunch (OPEFB) fiber were prepared by melt blending method. Prior to mixing, the fiber was modified through bleaching treatment using hydrogen peroxide. Bleached fiber composite showed an improvement in mechanical properties as compared to untreated fiber composite due to the enhanced fiber/matrix interfacial adhesion. Interestingly, fiber bleaching treatment also improved the physical appearance of th...

  13. Compostability assessment of nano-reinforced poly(lactic acid) films.

    Science.gov (United States)

    Balaguer, M P; Aliaga, C; Fito, C; Hortal, M

    2016-02-01

    Nanomaterials can provide plastics with great advantages on mechanical and active properties (i.e. release and capture of specific substances). Therefore, packaging is expected to become one of the leading applications for these substances by 2020. There are some applications already in the market. Nevertheless, there is still some areas under development. A key issue to be analyzed is the end-of-life of these materials once they become waste, and specifically when nanomaterials are used in biodegradable products. The present study evaluated the disintegration, biodegradability, and ecotoxicity of poly(lactic acid) films reinforced with the three following nanomaterials: (1) montmorillonite modified with an ammonium quaternary salt, (2) calcium carbonate and (3) silicon dioxide. Results on disintegration showed that films completely disintegrated into visually indistinguishable residues after 6-7weeks of incubation in composting environment. Moreover, no differences were observed in the evolution of the bioresidue with respect to color, aspect, and odor in comparison with the control. It was also observed that nanomaterials did not significantly reduce the level of biodegradability of PLA (p>0.05). In fact, biodegradation was higher, without finding significant differences (p>0.05), in all the nano-reinforced samples with respect to PLA after 130days in composting (9.4% in PLA+Nano-SiO2; 34.0% in PLA+Clay1; 48.0% in PLA+Nano-CaCO3). Finally, no significant differences (p>0.05) in ecotoxicity in plants were observed as a result of the incorporation of nanoparticles in the PLA matrix. PMID:26589869

  14. Thermogravimetric and DSC testing of poly(lactic acid) nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Mróz, Patrycja; Białas, Sylwia [Faculty of Process and Environmental Engineering, Technical University of Łódź, Wólczańska 15 Street, 90-924 Łódź (Poland); Mucha, Maria, E-mail: muchama@wipos.p.lodz.pl [Faculty of Process and Environmental Engineering, Technical University of Łódź, Wólczańska 15 Street, 90-924 Łódź (Poland); Kaczmarek, Halina [Nicolaus Copernicus University, Faculty of Chemistry, Gagarin 7 Street, 87-100 Toruń (Poland)

    2013-12-10

    Highlights: • The presence of nanoadditivities in PLA matrix improves thermal stability of PLA. • Shielding effect main reason for PLA thermal stability by nanofillers. • Thermal degradation suppression in UV-irradiated PLA by the removing of unstable compounds. - Abstract: Polymer nanocomposites based on poly(lactic acid), PLA, and two types of nanofillers: nanosilver and nanoclay were obtained by casting method. The thermal properties of PLA and nanocomposites have been studied by thermogravimetric analysis (TA) and differential scanning calorimetry (DSC). All samples have been UV-irradiated and the effect of photoprocess on their thermal stability has been estimated. It was found that nanoadditives and UV irradiation causes an increase of the activation energy of PLA thermal decomposition. DSC result supplies information on glass transition and crystallization/melting processes in PLA in the presence of nanosilver or nanoclay, also after exposure to UV.

  15. Polylactic Acid Nanoparticles Targeted to Brain Microvascular Endothelial Cells

    Institute of Scientific and Technical Information of China (English)

    WANG Huafang; HU Yu; SUN Wangqiang; XIE Changsheng

    2005-01-01

    In this work, blank polylactic acid (PLA) nanoparticles with unstained surface were prepared by the nano-deposition method. On the basis of the preparation, the effect of surface modification on brain microvascular endothelial cells (BMECs) targeting was examined by in vivo experiments and fluorescence microscopy. The results showed that PLA nanoparticles are less toxic than PACA nanoparticles but their BMECs targeting is similar to PACA nanoparticles. The experiments suggest that drugs can be loaded onto the particles and become more stable through adsorption on the surface of PLA nanoparticles with high surface activity. The surface of PLA nanoparticles was obviously modified and the hydrophilicity was increased as well in the presence of non-ionic surfactants on PLA nanoparticles. As a targeting moiety, polysobate 80 (T-80) can facilitate BMECs targeting of PLA nanoparticles.

  16. NANOCOMPOSITES OF POLY(LACTIC ACID REINFORCED WITH CELLULOSE NANOFIBRILS

    Directory of Open Access Journals (Sweden)

    Liping Zhang

    2010-06-01

    Full Text Available A chemo-mechanical method was used to prepare cellulose nanofibrils dispersed uniformly in an organic solvent. Poly(ethylene glycol (PEG 1000 was added to the matrix as a compatibilizer to improve the interfacial interaction between the hydrophobic poly(lactic acid (PLA and the hydrophilic cellulose nanofibrils. The composites obtained by solvent casting methods from N,N-Dimethylacetamide (DMAc were characterized by tensile testing machine, atomic force microscope (AFM, scanning electron microscope (SEM, and Fourier transform infrared spectroscopy (FT-IR. The tensile test results indicated that, by adding PEG to the PLA and the cellulose nanofibrils matrix, the tensile strength and the elongation rate increased by 56.7% and 60%, respectively, compared with the PLA/cellulose nanofibrils composites. The FT-IR analysis successfully showed that PEG improved the intermolecular interaction, which is based on the existence of inter-molecular hydrogen bonding among PLA, PEG, and cellulose nanofibrils.

  17. Application of Lemongrass Oil-Containing Polylactic Acid Films to the Packaging of Pork Sausages

    Science.gov (United States)

    2016-01-01

    Polylactic acid (PLA) is a biodegradable and renewable polymer, which represents a valuable alternative to plastic packaging films, often associated with environmental problems. In this study, we tested the suitability of PLA as a biodegradable packaging film and assessed the antimicrobial activity of lemongrass oil (LO), incorporated into the PLA film in different concentrations. To obtain the optimal physical properties for PLA films, tensile strength, elongation at break, and water vapor permeability were measured under different preparation conditions. In addition, the antimicrobial activity of the LO contained in the PLA film against Listeria monocytogenes was investigated by disc diffusion and viable cell count. Among all concentrations tested, 2% LO was the most suitable in terms of antimicrobial activity and physical properties of the PLA film. Based on these results, we used the PLA film containing 2% LO to pack pork sausages; after 12 d of storage at 4℃, the population of inoculated L. monocytogenes in the sausage samples wrapped with the PLA film containing 2% LO was reduced by 1.47 Log CFU/g compared with the control samples. Our data indicate that PLA films containing 2% LO represent a valuable means for antimicrobial sausage packaging. PMID:27433114

  18. Application of Lemongrass Oil-Containing Polylactic Acid Films to the Packaging of Pork Sausages.

    Science.gov (United States)

    Yang, Hyun-Ju; Song, Kyung Bin

    2016-01-01

    Polylactic acid (PLA) is a biodegradable and renewable polymer, which represents a valuable alternative to plastic packaging films, often associated with environmental problems. In this study, we tested the suitability of PLA as a biodegradable packaging film and assessed the antimicrobial activity of lemongrass oil (LO), incorporated into the PLA film in different concentrations. To obtain the optimal physical properties for PLA films, tensile strength, elongation at break, and water vapor permeability were measured under different preparation conditions. In addition, the antimicrobial activity of the LO contained in the PLA film against Listeria monocytogenes was investigated by disc diffusion and viable cell count. Among all concentrations tested, 2% LO was the most suitable in terms of antimicrobial activity and physical properties of the PLA film. Based on these results, we used the PLA film containing 2% LO to pack pork sausages; after 12 d of storage at 4℃, the population of inoculated L. monocytogenes in the sausage samples wrapped with the PLA film containing 2% LO was reduced by 1.47 Log CFU/g compared with the control samples. Our data indicate that PLA films containing 2% LO represent a valuable means for antimicrobial sausage packaging.

  19. Application of Lemongrass Oil-Containing Polylactic Acid Films to the Packaging of Pork Sausages.

    Science.gov (United States)

    Yang, Hyun-Ju; Song, Kyung Bin

    2016-01-01

    Polylactic acid (PLA) is a biodegradable and renewable polymer, which represents a valuable alternative to plastic packaging films, often associated with environmental problems. In this study, we tested the suitability of PLA as a biodegradable packaging film and assessed the antimicrobial activity of lemongrass oil (LO), incorporated into the PLA film in different concentrations. To obtain the optimal physical properties for PLA films, tensile strength, elongation at break, and water vapor permeability were measured under different preparation conditions. In addition, the antimicrobial activity of the LO contained in the PLA film against Listeria monocytogenes was investigated by disc diffusion and viable cell count. Among all concentrations tested, 2% LO was the most suitable in terms of antimicrobial activity and physical properties of the PLA film. Based on these results, we used the PLA film containing 2% LO to pack pork sausages; after 12 d of storage at 4℃, the population of inoculated L. monocytogenes in the sausage samples wrapped with the PLA film containing 2% LO was reduced by 1.47 Log CFU/g compared with the control samples. Our data indicate that PLA films containing 2% LO represent a valuable means for antimicrobial sausage packaging. PMID:27433114

  20. Partial replacement effect of montmorillonite with cellulose nanowhiskers on polylactic acid nanocomposites.

    Science.gov (United States)

    Arjmandi, Reza; Hassan, Azman; Mohamad Haafiz, M K; Zakaria, Zainoha

    2015-11-01

    In this study, hybrid montmorillonite/cellulose nanowhiskers (MMT/CNW) reinforced polylactic acid (PLA) nanocomposites were produced through solution casting. The CNW filler was first isolated from microcrystalline cellulose by chemical swelling technique. The partial replacement of MMT with CNW in order to produce PLA/MMT/CNW hybrid nanocomposites was performed at 5 parts per hundred parts of polymer (phr) fillers content, based on highest tensile strength values as reported in our previous study. MMT were partially replaced with various amounts of CNW (1, 2, 3, 4 and 5phr). The tensile, thermal, morphological and biodegradability properties of PLA hybrid nanocomposites were investigated. The highest tensile strength of hybrid nanocomposites was obtained with the combination of 4phr MMT and 1phr CNW. Interestingly, the ductility of hybrid nanocomposites increased significantly by 79% at this formulation. The Young's modulus increased linearly with increasing CNW content. Thermogravimetric analysis illustrated that the partial replacement of MMT with CNW filler enhanced the thermal stability of the PLA. This is due to the relatively good dispersion of fillers in the hybrid nanocomposites samples as revealed by transmission electron microscopy. Interestingly, partial replacements of MMT with CNW improved the biodegradability of hybrid nanocomposites compared to PLA/MMT and neat PLA. PMID:26234577

  1. Partial replacement effect of montmorillonite with cellulose nanowhiskers on polylactic acid nanocomposites.

    Science.gov (United States)

    Arjmandi, Reza; Hassan, Azman; Mohamad Haafiz, M K; Zakaria, Zainoha

    2015-11-01

    In this study, hybrid montmorillonite/cellulose nanowhiskers (MMT/CNW) reinforced polylactic acid (PLA) nanocomposites were produced through solution casting. The CNW filler was first isolated from microcrystalline cellulose by chemical swelling technique. The partial replacement of MMT with CNW in order to produce PLA/MMT/CNW hybrid nanocomposites was performed at 5 parts per hundred parts of polymer (phr) fillers content, based on highest tensile strength values as reported in our previous study. MMT were partially replaced with various amounts of CNW (1, 2, 3, 4 and 5phr). The tensile, thermal, morphological and biodegradability properties of PLA hybrid nanocomposites were investigated. The highest tensile strength of hybrid nanocomposites was obtained with the combination of 4phr MMT and 1phr CNW. Interestingly, the ductility of hybrid nanocomposites increased significantly by 79% at this formulation. The Young's modulus increased linearly with increasing CNW content. Thermogravimetric analysis illustrated that the partial replacement of MMT with CNW filler enhanced the thermal stability of the PLA. This is due to the relatively good dispersion of fillers in the hybrid nanocomposites samples as revealed by transmission electron microscopy. Interestingly, partial replacements of MMT with CNW improved the biodegradability of hybrid nanocomposites compared to PLA/MMT and neat PLA.

  2. Thermal characterization of polyhydroxyalkanoates and poly(lactic acid) blends obtained by injection molding

    OpenAIRE

    Loureiro, Nuno Calçada; Ghosh, Satyabrata; Viana, J. C.; Esteves, José Luis

    2015-01-01

    In this work we present the thermal characterization of the full scope of polyhydroxyalcanoate and poly(lactic acid) blends obtain by injection molding. Blends of polyhydroxyalcanoate and poly(lactic acid) (PHA/PLA) were prepared in different compositions ranging from 0–100% in steps of 10%. The blends were injection molded and then characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD). The increment of PHA fractio...

  3. Poly(lactic acid) degradable plastics, coatings, and binders

    Energy Technology Data Exchange (ETDEWEB)

    Bonsignore, P.V.; Coleman, R.D.; Mudde, J.P.

    1992-01-01

    Biochemical processes to derive value from the management of high carbohydrate food wastes, such as potato starch, corn starch, and cheese whey permeate, have typically been limited to the production of either ethanol or methane. Argonne National Laboratory (ANL) believes that lactic acid presents an attractive option for an alternate fermentation end product, especially in light of lactic acids' being a viable candidate for conversion to environmentally safe poly(lactic acid) (PLA) degradable plastics, coatings, and binders. Technology is being developed at ANL to permit a more cost effective route to modified high molecular weight PLA. Preliminary data on the degradation behavior of these modified PLAs shows the retention to the inherent hydrolytic degradability of the PLA modified, however, by introduced compositional variables. A limited study was done on the hydrolytic stability of soluble oligomers of poly(L-lactic acid). Over a 34 day hold period, water-methanol solutions of Pl-LA oligomers in the 2-10 DP range retained some 75% of their original molecular weight.

  4. Poly(lactic acid) degradable plastics, coatings, and binders

    Energy Technology Data Exchange (ETDEWEB)

    Bonsignore, P.V.; Coleman, R.D.; Mudde, J.P.

    1992-05-01

    Biochemical processes to derive value from the management of high carbohydrate food wastes, such as potato starch, corn starch, and cheese whey permeate, have typically been limited to the production of either ethanol or methane. Argonne National Laboratory (ANL) believes that lactic acid presents an attractive option for an alternate fermentation end product, especially in light of lactic acids` being a viable candidate for conversion to environmentally safe poly(lactic acid) (PLA) degradable plastics, coatings, and binders. Technology is being developed at ANL to permit a more cost effective route to modified high molecular weight PLA. Preliminary data on the degradation behavior of these modified PLAs shows the retention to the inherent hydrolytic degradability of the PLA modified, however, by introduced compositional variables. A limited study was done on the hydrolytic stability of soluble oligomers of poly(L-lactic acid). Over a 34 day hold period, water-methanol solutions of Pl-LA oligomers in the 2-10 DP range retained some 75% of their original molecular weight.

  5. In vivo biomechanical properties of biodegradable polylactic acid-glycolic acid lumbar intertransverse fusion cage%可生物降解聚乳酸-乙醇酸共聚物腰椎横突间融合器的体内生物力学

    Institute of Scientific and Technical Information of China (English)

    姚豹; 李开南; 聂海

    2014-01-01

    BACKGROUND:To increase the fusion rate and further reduce complications, Li Kai-nan and co-workers designed an absorbable intertransverse fusion cage made from biodegradable polylactic acid-glycolic acid (PLGA) material (the patent number of State Intelectual Property Office of China: 200810148018.0). OBJECTIVE:To investigate the biomechanical variation of the biodegradable PLGA lumbar intertransverse fusion cage in vivo. METHODS:Ninety-six Boer goats were randomly divided into experimental and control groups. The biodegradable PLGA lumbar intertransverse fusion cage was placed in the L4/5 intertransverse segment in the experimental group; the same size lilac bone was placed in the same position in the control group. The whole lumbar vertebrae were taken to make specimens at 1, 3, 6, 9, 12, 18 months after operation. Three-dimensional spine motion measurement system was used to calculate the range of motion of the L4/5 segment in the anteflexion, rear extension, left/right lateral bending and rotation states. RESULTS AND CONCLUSION:Anteflexion, rear extension, lateral bending and rotation motions of both groups reduced successively at 1, 3, 6, 9, 12 and 18 months after operation. The range of anteflexion movements in the experimental group was lower than that of the control group at 3, 9, 12 postoperative months (P   目的:研究聚乳酸-乙醇酸共聚物腰椎横突间融合器在动物体内的生物力学变化情况。  方法:采用电脑将96只波尔山羊随机分均为实验组和对照组,咬除L4横突下缘和L5横突上缘的皮质骨,实验组在羊右侧L4、5横突间隙置入填有自体髂骨的聚乳酸-乙醇酸共聚物腰椎横突间融合器;对照组在相应位置植入同融合器大小相当的自体髂骨块,分别于术后1,3,6,9,12,18个月取整个腰椎制成标本,用脊柱三维运动测量系统测算各组标本L4、L5节段前屈、后伸、侧屈、旋转的运动范围。  结果与结

  6. Fundamentals of poly(lactic acid) microstructure, crystallization behavior, and properties

    Science.gov (United States)

    Kang, Shuhui

    Poly(lactic acid) is an environmentally-benign biodegradable and sustainable thermoplastic material, which has found broad applications as food packaging films and as non-woven fibers. The crystallization and deformation mechanisms of the polymer are largely determined by the distribution of conformation and configuration. Knowledge of these mechanisms is needed to understand the mechanical and thermal properties on which processing conditions mainly depend. In conjunction with laser light scattering, Raman spectroscopy and normal coordinate analysis are used in this thesis to elucidate these properties. Vibrational spectroscopic theory, Flory's rotational isomeric state (RIS) theory, Gaussian chain statistics and statistical mechanics are used to relate experimental data to molecular chain structure. A refined RIS model is proposed, chain rigidity recalculated and chain statistics discussed. A Raman spectroscopic characterization method for crystalline and amorphous phase orientation has been developed. A shrinkage model is also proposed to interpret the dimensional stability for fibers and uni- or biaxially stretched films. A study of stereocomplexation formed by poly(l-lactic acid) and poly(d-lactic acid) is also presented.

  7. 聚乳酸的合成方法%Synthesis of polylactic acid

    Institute of Scientific and Technical Information of China (English)

    梁博

    2008-01-01

    聚乳酸是一类具有优良生物相容性和可生物降解的高分子材料,被广泛应用于医用领域,受到越来越多的关注.聚乳酸的合成主要有两种方法: 丙交酯的开环聚合和乳酸直接缩聚.综述近年来聚乳酸合成研究的最新进展,介绍了聚乳酸聚合的两种高效方法-反应挤出法和直接-固相聚合法,并展望了聚乳酸合成研究的前景.%Polylactic acid (PLA) is a biocompatible and biodegradable polymer, thus it is widely used in the medical area and is much more attractive. There are two main methods to synthetizing PLA, ring-opening polymerization of lactide and condensation polymerization of lactic acid. In this paper, the process of the new research of the PLA synthesis was reviewed. Beside, the PLA synthesis methods of reactive extrusion and direct melting polycondensation were introduced, which are two high efficiency methods. Finally, the foreground of PLA synthesis was prospected.

  8. New Polylactic Acid Composites Reinforced with Artichoke Fibers

    Directory of Open Access Journals (Sweden)

    Luigi Botta

    2015-11-01

    Full Text Available In this work, artichoke fibers were used for the first time to prepare poly(lactic acid (PLA-based biocomposites. In particular, two PLA/artichoke composites with the same fiber loading (10% w/w were prepared by the film-stacking method: the first one (UNID reinforced with unidirectional long artichoke fibers, the second one (RANDOM reinforced by randomly-oriented long artichoke fibers. Both composites were mechanically characterized in tensile mode by quasi-static and dynamic mechanical tests. The morphology of the fracture surfaces was analyzed through scanning electron microscopy (SEM. Moreover, a theoretical model, i.e., Hill’s method, was used to fit the experimental Young’s modulus of the biocomposites. The quasi-static tensile tests revealed that the modulus of UNID composites is significantly higher than that of the neat PLA (i.e., ~40%. Moreover, the tensile strength is slightly higher than that of the neat matrix. The other way around, the stiffness of RANDOM composites is not significantly improved, and the tensile strength decreases in comparison to the neat PLA.

  9. Formation and Investigation of Corona Charged Films from Polylactic Acid

    Science.gov (United States)

    Gencheva, E. A.; Yovcheva, T. A.; Marudova, M. G.; Viraneva, A. P.; Bodurov, I. P.; Mekishev, G. A.; Sainov, S. H.

    2010-01-01

    The aim of the present work is the development of technology for formation of corona charged electret films from polylactic acid and investigation of their structural, optical and electret properties. Polylactide films with different degree of crystalinity were prepared by casting of poly-L-lactide and poly-DL lactide blended solutions. Then glass transition, crystallization and melting temperatures, as well as the crystalinity degree were determined by a differential scanning calorimetry. The charging of the samples in a corona discharge was carried out by means of a conventional corona triode system. Sample surface potential was measured by the method of the vibrating electrode with compensation. The time dependences of the sample surface potential under room conditions were studied for 50 days. The effect of lower pressure on the surface potential of charged samples was investigated. It was established that the reduced pressure leaded to the surface potential decay of the PLA electrets. The same effect was earlier observed for other polymer films. The optical characteristics—surface refractive index and optical dispersion, were determined by the method of the disappearing diffraction pattern using a laser refractometer.

  10. Evaluation of polylactic acid nanoparticles safety using Drosophila model.

    Science.gov (United States)

    Legaz, Sophie; Exposito, Jean-Yves; Lethias, Claire; Viginier, Barbara; Terzian, Christophe; Verrier, Bernard

    2016-10-01

    Cytotoxicity of nanoparticles and their sub-lethal effect on cell behavior and cell fate are a high topic of studies in the nanomaterial field. With an explosion of nanoparticle types (size, shape, polarity, stiffness, composition, etc.), Drosophila has become an attractive animal model for high throughput analysis of these nanocarriers in the drug delivery field with applications in cancer therapy, or simply to generate a fast and complete cytotoxic study of a peculiar nanoparticle. In respect to that, we have conducted an in cellulo study of poly(lactic acid) (PLA) nanoparticle cytotoxicity, and determined that near lethal nanoparticle doses, oxidative stress as well as P53 and ATP pathways may lead to cell cycle arrest at G1, and ultimately to cell death. Neither viability nor the development of Drosophila larvae are affected by the ingestion of PLA nanoparticles at sub-lethal concentrations. Drosophila will be a useful model to study PLA and PLA-modified nanoparticle toxicity, and nanoparticle fate after ingestion. PMID:27108761

  11. Fracture behavior of quenched poly(lactic acid

    Directory of Open Access Journals (Sweden)

    2011-01-01

    Full Text Available The effect of a quenching treatment applied on heated cast sheet extruded films of two poly(lactic acid (PLA commercial grades, with different optical purities, was studied. The thermal and mechanical properties of the films, as well as their fracture behavior, were assessed by differential scanning calorimetry (DSC, tensile tests, and the essential work of fracture (EWF approach. The heating-quenching treatment causes a de-aging effect with an increase in the free volume of polymer chains evidenced by a decrease in the glass transition temperature (Tg and a decrease in the tensile stiffness and yield stress. As a result, there is an abrupt increase in ductility, finding a dramatic change in the fracture behavior, from brittle to ductile. The use of digital image correlation (DIC of the strain field analysis during fracture testing has allowed relating the decrease on the yield stress promoted by quenching with the crack propagation kinetics. The use of the EWF method to characterize the fracture toughness of PLA has allowed to measure this enhancement on toughness, finding that the specific essential work of fracture (we and the plastic term (βwp parameters increased 120% and 1200%, respectively, after the quenching process.

  12. Cell patterning on polylactic acid through surface-tethered oligonucleotides.

    Science.gov (United States)

    Matsui, Toshiki; Arima, Yusuke; Takemoto, Naohiro; Iwata, Hiroo

    2015-02-01

    Polylactic acid (PLA) is a candidate material to prepare scaffolds for 3-D tissue regeneration. However, cells do not adhere or proliferate well on the surface of PLA because it is hydrophobic. We report a simple and rapid method for inducing cell adhesion to PLA through DNA hybridization. Single-stranded DNA (ssDNA) conjugated to poly(ethylene glycol) (PEG) and to a terminal phospholipid (ssDNA-PEG-lipid) was used for cell surface modification. Through DNA hybridization, modified cells were able to attach to PLA surfaces modified with complementary sequence (ssDNA'). Different cell types can be attached to PLA fibers and films in a spatially controlled manner by using ssDNAs with different sequences. In addition, they proliferate well in a culture medium supplemented with fetal bovine serum. The coexisting modes of cell adhesion through DNA hybridization and natural cytoskeletal adhesion machinery revealed no serious effects on cell growth. The combination of a 3-D scaffold made of PLA and cell immobilization on the PLA scaffold through DNA hybridization will be useful for the preparation of 3-D tissue and organs.

  13. Dielectric Relaxation Phenomena of Polylactic Acid with -Crystalline Chitin

    Directory of Open Access Journals (Sweden)

    Katsuyoshi Shinyama

    2012-01-01

    Full Text Available -crystalline chitin was added to polylactic acid (PLA, and this PLA was then heat-treated at 100∘C for one minute. The crystallinity of the heat-treated PLA increased to more than 40%, and its crystallization speed also increased significantly. The temperature dependency of these materials’ relative permittivity ( and relative dielectric loss factor ( was also examined. The dielectric absorption peak value in  curve of the PLA to which chitin was added and was smaller than that of PLA without chitin. Additionally, the Havriliak-Negami relaxation function was used to produce approximation curves for the frequency dependency of  and  of chitin with PLA added at 80∘C. As a result, the relaxation strength (Δ of the chitin with PLA added was smaller than that of the PLA without chitin, and the relaxation time ( of the chitin with PLA added was approximately 2.5 times larger than that of the PLA without chitin.

  14. Evaluation of polylactic acid nanoparticles safety using Drosophila model.

    Science.gov (United States)

    Legaz, Sophie; Exposito, Jean-Yves; Lethias, Claire; Viginier, Barbara; Terzian, Christophe; Verrier, Bernard

    2016-10-01

    Cytotoxicity of nanoparticles and their sub-lethal effect on cell behavior and cell fate are a high topic of studies in the nanomaterial field. With an explosion of nanoparticle types (size, shape, polarity, stiffness, composition, etc.), Drosophila has become an attractive animal model for high throughput analysis of these nanocarriers in the drug delivery field with applications in cancer therapy, or simply to generate a fast and complete cytotoxic study of a peculiar nanoparticle. In respect to that, we have conducted an in cellulo study of poly(lactic acid) (PLA) nanoparticle cytotoxicity, and determined that near lethal nanoparticle doses, oxidative stress as well as P53 and ATP pathways may lead to cell cycle arrest at G1, and ultimately to cell death. Neither viability nor the development of Drosophila larvae are affected by the ingestion of PLA nanoparticles at sub-lethal concentrations. Drosophila will be a useful model to study PLA and PLA-modified nanoparticle toxicity, and nanoparticle fate after ingestion.

  15. 聚乳酸微球的制备%Preparation of polylactic acid microspheres

    Institute of Scientific and Technical Information of China (English)

    孟立山; 姚新建

    2011-01-01

    Using L-lactic acid as raw materials and tin as a catalyst, and through the activity of lactide ring-opening polymerization, the controlled molecular weight polylactic acid was synthesized. FTIR results showed that controlled molecular weight polylactic acid was synthesized. Using dichloromethane as solvent, polyvinyl alcohol as surfactant, polylactic acid microspheres were prepared. Effect of PVA concentration on the polylactic acid microspheres was researched. Results showed that when the PVA concentration increased,the microspheres became smaller, but the particle size distribution decreased. Concentration of PVA was 1 % , polylactic acid into the ball was better.%以L-乳酸为原料,锡粒为催化剂,实现了丙交酯的开环聚合反应,红外光谱结果表明,合成了分子量可控的聚乳酸.以二氯甲烷为溶剂,聚乙烯醇为表面活性剂,制备了聚乳酸微球,研究了聚乙烯醇浓度对聚乳酸微球的影响.结果表明,当聚乙烯醇浓度增加时,微球半径变小,但粒径分布均匀度下降,聚乙烯醇浓度为1%时,聚乳酸成球效果较好.

  16. 聚乳酸载药系统的研究进展%The Research Progress of Polylactic Acid Containing Drug Delivery System

    Institute of Scientific and Technical Information of China (English)

    林丽丽

    2012-01-01

    Polylactic acid and its copolymers,due to its biocompatibility and biodegradability,were widely used in medicine and biology.The paper summarized the study of new drug-loaded polylactide and its copolymers at home and abroad.Polylactic acid to illustrate the advantages as a drug carrier and development prospects.%聚乳酸及其共聚物由于其生物相容性和生物可降解性,被广泛应用于医药和生物学领域。文章就国内外对聚乳酸及其共聚物作为新型载药系统的研究,进行了归纳总结。旨在说明聚乳酸作为药物载体的优势和发展前景。

  17. CHARACTERIZATION OF POLYLACTIC ACID COLLOIDS FOR IN SITU BIOREMEDIATION

    Energy Technology Data Exchange (ETDEWEB)

    Ashley N. Westbrook

    2003-07-01

    Groundwater contamination is a widespread problem. As human activities generate chemical wastes, we seek quick, yet not always environmentally friendly, ways to dispose of them. Often, chemicals are dumped into waste containers and buried. Unfortunately, these chemicals may spill or leak, seep deeper into the ground, and eventually reach groundwater. Chlorinated organic solvents such as trichloroethene, tetrachloroethane, and chloroform are common contaminants in groundwater [1]. These solvents originate from chemical spills, tank leaks, and waste disposal practices [2]. Such contaminants are harmful to humans, and need to be removed to restore clean groundwater. There are two types of methods to clean chemically contaminated soil and groundwater: ex situ and in situ. Both types have advantages and disadvantages. In situ remediation avoids the cost of removing the contaminated material and has a lower risk of worker exposure to the contaminants. One in situ technique that shows promise is remediation, which uses microorganisms to anaerobically degrade contaminants. In bioremediation in situ, the microorganisms that are already present in the ground utilize nutrients that are injected into the ground to metabolize the contaminants into nonhazardous materials. The nutrients serve as a carbon source for the microbes. Though this method has been used with some success, there have been problems with too rapid release of nutrients to the microbes. In these cases, the microbes multiplied too rapidly and caused biofouling. This can occur when the nutrient content of the bioremediation solution is too high, as when lactate or lactic acid is the nutrient. Lactic acid is typically produced in carbohydrate matter by fermentation, and is used mainly in the food and pharmaceutical industries [3]. Because it has been found difficult to uniformly distribute lactate solutions in a contaminated area due to biofouling, it was suggested that polylactic acid, in colloidal form, be used

  18. Practical preparation procedures for docetaxel-loaded nanoparticles using polylactic acid-co-glycolic acid

    Directory of Open Access Journals (Sweden)

    Keum CG

    2011-10-01

    Full Text Available Chang-Gu Keum1*, Young-Wook Noh1*, Jong-Suep Baek1, Ji-Ho Lim1, Chan-Ju Hwang1, Young-Guk Na1, Sang-Chul Shin2, Cheong-Weon Cho11College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Gungdong, Yuseonggu, Daejeon, South Korea; 2College of Pharmacy, Chonnam National University, Yongbongdong, Buggu, Gwangju, South Korea *These authors contributed equally to this work Background: Nanoparticles fabricated from the biodegradable and biocompatible polymer, polylactic-co-glycolic acid (PLGA, are the most intensively investigated polymers for drug delivery systems. The objective of this study was to explore fully the development of a PLGA nanoparticle drug delivery system for alternative preparation of a commercial formulation. In our nanoparticle fabrication, our purpose was to compare various preparation parameters. Methods: Docetaxel-loaded PLGA nanoparticles were prepared by a single emulsion technique and solvent evaporation. The nanoparticles were characterized by various techniques, including scanning electron microscopy for surface morphology, dynamic light scattering for size and zeta potential, x-ray photoelectron spectroscopy for surface chemistry, and high-performance liquid chromatography for in vitro drug release kinetics. To obtain a smaller particle, 0.2% polyvinyl alcohol, 0.03% D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS, 2% Poloxamer 188, a five-minute sonication time, 130 W sonication power, evaporation with magnetic stirring, and centrifugation at 8000 rpm were selected. To increase encapsulation efficiency in the nanoparticles, certain factors were varied, ie, 2–5 minutes of sonication time, 70–130 W sonication power, and 5–25 mg drug loading. Results: A five-minute sonication time, 130 W sonication power, and a 10 mg drug loading amount were selected. Under these conditions, the nanoparticles reached over 90% encapsulation efficiency. Release kinetics showed that 20

  19. Poly(Lactic Acid Filled with Cassava Starch-g-Soybean Oil Maleate

    Directory of Open Access Journals (Sweden)

    Nopparut Kiangkitiwan

    2013-01-01

    Full Text Available Poly(lactic acid, PLA, is a biodegradable polymer, but its applications are limited by its high cost and relatively poorer properties when compared to petroleum-based plastics. The addition of starch powder into PLA is one of the most promising efforts because starch is an abundant and cheap biopolymer. However, the challenge is the major problem associated with poor interfacial adhesion between the hydrophilic starch granules and the hydrophobic PLA, leading to poorer mechanical properties. In this paper, soybean oil maleate (SOMA was synthesized by grafting soybean oil with various weight percents of maleic anhydride (MA using dicumyl peroxide (DCP as an initiator. Then, SOMA was employed for the surface modifying of cassava starch powder, resulting in SOMA-g-STARCH. The obtained SOMA-g-STARCH was mixed with PLA in various weight ratios using twin-screw extruder, resulting in PLA/SOMA-g-STARCH. Finally, the obtained PLA/SOMA-g-STARCH composites were prepared by a compression molding machines. The compatibility, thermal properties, morphology properties, and mechanical properties were characterized and evaluated. The results showed that the compatibility, surface appearance, and mechanical properties at 90 : 10 and 80 : 20 ratios of PLA/SOMA-g-STARCH were the best.

  20. Poly(lactic acid)/chitosan hybrid nanoparticles for controlled release of anticancer drug.

    Science.gov (United States)

    Wang, Wenlong; Chen, Shu; Zhang, Liang; Wu, Xi; Wang, Jiexin; Chen, Jian-Feng; Le, Yuan

    2015-01-01

    Poly(lactic acid) (PLA) is a kind of non-toxic biological materials with excellent absorbability, biocompatibility and biodegradability, which can be used for drug release, tissue engineering and surgical treatment applications. In this study, we prepared chitosan modified PLA nanoparticles as carriers for encapsulation of docetaxel by anti-solvent precipitation method. The morphology, particle size, zeta potential and composition of the PLA/chitosan were characterized by SEM, DLS, FTIR and XPS. As-prepared PLA/chitosan particles exhibited average size of 250 nm and showed very narrow distribution with polydispersity index of 0.098. Their large surface charge-ability was confirmed by zeta potential value of 53.9 mV. Docetaxel was released from PLA/chitosan nanoparticles with 40% initial burst release in 5 h and 70% cumulative release within 24 h, while from PLA nanoparticles 65% of docetaxel was released in 5h. In vitro drug release study demonstrated that PLA/chitosan nanoparticles prolonged drug release and decreased the burst release over the unmodified PLA nanoparticles. These results illustrated high potential of chitosan modified PLA nanoparticles for usage as anticancer drug carriers. PMID:25492016

  1. Mechanical, Thermal and Morphological Properties of Poly(lactic acid/Epoxidized Palm Olein Blend

    Directory of Open Access Journals (Sweden)

    Hazimah Abu Hassan

    2012-10-01

    Full Text Available Poly(lactic acid (PLA is known to be a useful material in substituting the conventional petroleum-based polymer used in packaging, due to its biodegradability and high mechanical strength. Despite the excellent properties of PLA, low flexibility has limited the application of this material. Thus, epoxidized palm olein (EPO was incorporated into PLA at different loadings (1, 2, 3, 4 and 5 wt% through the melt blending technique and the product was characterized. The addition of EPO resulted in a decrease in glass transition temperature and an increase of elongation-at-break, which indicates an increase in the PLA chain mobility. PLA/EPO blends also exhibited higher thermal stability than neat PLA. Further, the PLA/1 wt% EPO blend showed enhancement in the tensile, flexural and impact properties. This is due to improved interaction in the blend producing good compatible morphologies, which can be revealed by Scanning Electron Microscopy (SEM analysis. Therefore, PLA can be efficiently plasticized by EPO and the feasibility of its use as flexible film for food packaging should be considered.

  2. Mechanical, thermal and morphological properties of poly(lactic acid)/epoxidized palm olein blend.

    Science.gov (United States)

    Silverajah, V S Giita; Ibrahim, Nor Azowa; Zainuddin, Norhazlin; Yunus, Wan Md Zin Wan; Hassan, Hazimah Abu

    2012-10-08

    Poly(lactic acid) (PLA) is known to be a useful material in substituting the conventional petroleum-based polymer used in packaging, due to its biodegradability and high mechanical strength. Despite the excellent properties of PLA, low flexibility has limited the application of this material. Thus, epoxidized palm olein (EPO) was incorporated into PLA at different loadings (1, 2, 3, 4 and 5 wt%) through the melt blending technique and the product was characterized. The addition of EPO resulted in a decrease in glass transition temperature and an increase of elongation-at-break, which indicates an increase in the PLA chain mobility. PLA/EPO blends also exhibited higher thermal stability than neat PLA. Further, the PLA/1 wt% EPO blend showed enhancement in the tensile, flexural and impact properties. This is due to improved interaction in the blend producing good compatible morphologies, which can be revealed by Scanning Electron Microscopy (SEM) analysis. Therefore, PLA can be efficiently plasticized by EPO and the feasibility of its use as flexible film for food packaging should be considered.

  3. Poly(lactic acid)/chitosan hybrid nanoparticles for controlled release of anticancer drug.

    Science.gov (United States)

    Wang, Wenlong; Chen, Shu; Zhang, Liang; Wu, Xi; Wang, Jiexin; Chen, Jian-Feng; Le, Yuan

    2015-01-01

    Poly(lactic acid) (PLA) is a kind of non-toxic biological materials with excellent absorbability, biocompatibility and biodegradability, which can be used for drug release, tissue engineering and surgical treatment applications. In this study, we prepared chitosan modified PLA nanoparticles as carriers for encapsulation of docetaxel by anti-solvent precipitation method. The morphology, particle size, zeta potential and composition of the PLA/chitosan were characterized by SEM, DLS, FTIR and XPS. As-prepared PLA/chitosan particles exhibited average size of 250 nm and showed very narrow distribution with polydispersity index of 0.098. Their large surface charge-ability was confirmed by zeta potential value of 53.9 mV. Docetaxel was released from PLA/chitosan nanoparticles with 40% initial burst release in 5 h and 70% cumulative release within 24 h, while from PLA nanoparticles 65% of docetaxel was released in 5h. In vitro drug release study demonstrated that PLA/chitosan nanoparticles prolonged drug release and decreased the burst release over the unmodified PLA nanoparticles. These results illustrated high potential of chitosan modified PLA nanoparticles for usage as anticancer drug carriers.

  4. Development of structure and properties during thermal calendering of polylactic acid (PLA fiber webs

    Directory of Open Access Journals (Sweden)

    2008-01-01

    Full Text Available Due to its thermoplastic and biodegradable nature, poly(lactic acid (PLA holds good promise in its increasing use in the form of fibers for medical, agricultural, apparel, upholstery, hygiene, and other applications. Most of the research being done on PLA fibers is to understand their production by melt spinning, solution spinning, and the structure-property relationships during fiber formation. Nonwovens are one of the important forms of the materials into which PLA polymer can be converted to create many useful products. Thermal bonding is the most widely used bonding technique employed to impart strength, and other useful characteristics to the nonwovens. However, there is limited research done to study the behavior of PLA fibers during thermal bonding of nonwovens. Hence the research was carried out to investigate the thermal bonding of nonwovens made from PLA staple fibers. The PLA fibers were carded and then calendered at different temperatures. The webs were characterized for their structure and properties. The observed results are discussed with respect to the investigated processing conditions.

  5. Magnetite-polylactic acid nanoparticles by surface initiated organocatalysis ring opening polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Alexandrina [National Institute of R and D for Isotopic and Molecular Technologies (Romania); Leistner, Joachim [Humboldt-University Berlin, Institute of Chemistry (Germany); Turcu, Rodica, E-mail: rodica.turcu@itim-cj.ro [National Institute of R and D for Isotopic and Molecular Technologies (Romania)

    2013-08-15

    Organocatalysis by 4-N,N-dimethylaminopyridine was employed for ring opening polymerization of lactide initiated at magnetic nanoparticles covered by glycerol phosphate or ascorbic acid phosphate. The resulting magnetite-polylactic acid nanoparticles exhibit high colloidal stability in water and alcohol. Their morphology was investigated by transmission electron microscopy and the chemical structure was elucidated by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The increase in mass after coating the nanoparticles was determined by thermogravimetric analysis, while dynamic light scattering revealed the increase in hydrodynamic size. Magnetic measurements revealed superparamagnetic behavior and high magnetization values. The magnetite-polylactic acid nanoparticles were further used for magnetic tagging of biotin.

  6. Poly-lactic acid and agarose gelatin play an active role in the recovery of spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective To investigate the role of poly-lactic acid and agarose gelatin in promoting the functional recovery of the injured spinal cord. Methods Poly-lactic acid (PLA) or agarose was embedded in the space between two stumps of the hemisectioned spinal cord. Immunohistochemistry was used to show astroglia proliferation and the infiltration of RhoA-positive cells. Locomotor activity recovery was evaluated by testing the function of hindlimbs. Results Astroglias and RhoA labeled non-neuronal cells accumulated in the area adjacent to the implant, while the number of RhoA-positive cells was decreased dramatically in the absence of implant. Animals implanted with agarose gelatin recovered more quickly than those with PLA, concomitant with a higher survival rate of the neurons. Conclusion Both PLA and agarose gelatin benefited the recovery of spinal cord after injury by providing a scaffold for astroglia processes. Modulation of the rigidity, pore size and inner structure of PLA and agarose gelatin might make these biodegradable materials more effective in the regeneration of the central nervous system (CNS).

  7. Sandwich-Architectured Poly(lactic acid)-Graphene Composite Food Packaging Films.

    Science.gov (United States)

    Goh, Kunli; Heising, Jenneke K; Yuan, Yang; Karahan, Huseyin E; Wei, Li; Zhai, Shengli; Koh, Jia-Xuan; Htin, Nanda M; Zhang, Feimo; Wang, Rong; Fane, Anthony G; Dekker, Matthijs; Dehghani, Fariba; Chen, Yuan

    2016-04-20

    Biodegradable food packaging promises a more sustainable future. Among the many different biopolymers used, poly(lactic acid) (PLA) possesses the good mechanical property and cost-effectiveness necessary of a biodegradable food packaging. However, PLA food packaging suffers from poor water vapor and oxygen barrier properties compared to many petroleum-derived ones. A key challenge is, therefore, to simultaneously enhance both the water vapor and oxygen barrier properties of the PLA food packaging. To address this issue, we design a sandwich-architectured PLA-graphene composite film, which utilizes an impermeable reduced graphene oxide (rGO) as the core barrier and commercial PLA films as the outer protective encapsulation. The synergy between the barrier and the protective encapsulation results in a significant 87.6% reduction in the water vapor permeability. At the same time, the oxygen permeability is reduced by two orders of magnitude when evaluated under both dry and humid conditions. The excellent barrier properties can be attributed to the compact lamellar microstructure and the hydrophobicity of the rGO core barrier. Mechanistic analysis shows that the large rGO lateral dimension and the small interlayer spacing between the rGO sheets have created an extensive and tortuous diffusion pathway, which is up to 1450-times the thickness of the rGO barrier. In addition, the sandwiched architecture has imbued the PLA-rGO composite film with good processability, which increases the manageability of the film and its competency to be tailored. Simulations using the PLA-rGO composite food packaging film for edible oil and potato chips also exhibit at least eight-fold extension in the shelf life of these oxygen and moisture sensitive food products. Overall, these qualities have demonstrated the high potential of a sandwich-architectured PLA-graphene composite film for food packaging applications.

  8. Sandwich-Architectured Poly(lactic acid)-Graphene Composite Food Packaging Films.

    Science.gov (United States)

    Goh, Kunli; Heising, Jenneke K; Yuan, Yang; Karahan, Huseyin E; Wei, Li; Zhai, Shengli; Koh, Jia-Xuan; Htin, Nanda M; Zhang, Feimo; Wang, Rong; Fane, Anthony G; Dekker, Matthijs; Dehghani, Fariba; Chen, Yuan

    2016-04-20

    Biodegradable food packaging promises a more sustainable future. Among the many different biopolymers used, poly(lactic acid) (PLA) possesses the good mechanical property and cost-effectiveness necessary of a biodegradable food packaging. However, PLA food packaging suffers from poor water vapor and oxygen barrier properties compared to many petroleum-derived ones. A key challenge is, therefore, to simultaneously enhance both the water vapor and oxygen barrier properties of the PLA food packaging. To address this issue, we design a sandwich-architectured PLA-graphene composite film, which utilizes an impermeable reduced graphene oxide (rGO) as the core barrier and commercial PLA films as the outer protective encapsulation. The synergy between the barrier and the protective encapsulation results in a significant 87.6% reduction in the water vapor permeability. At the same time, the oxygen permeability is reduced by two orders of magnitude when evaluated under both dry and humid conditions. The excellent barrier properties can be attributed to the compact lamellar microstructure and the hydrophobicity of the rGO core barrier. Mechanistic analysis shows that the large rGO lateral dimension and the small interlayer spacing between the rGO sheets have created an extensive and tortuous diffusion pathway, which is up to 1450-times the thickness of the rGO barrier. In addition, the sandwiched architecture has imbued the PLA-rGO composite film with good processability, which increases the manageability of the film and its competency to be tailored. Simulations using the PLA-rGO composite food packaging film for edible oil and potato chips also exhibit at least eight-fold extension in the shelf life of these oxygen and moisture sensitive food products. Overall, these qualities have demonstrated the high potential of a sandwich-architectured PLA-graphene composite film for food packaging applications. PMID:27028268

  9. Obtaining a Flexible Film Elaborated from Cassava Thermoplastic Starch and Polylactic Acid

    Directory of Open Access Journals (Sweden)

    Germán A. Arboleda

    2015-01-01

    Full Text Available A flexible film was obtained from a blend of cassava thermoplastic starch and polylactic acid, using maleic anhydride as coupling agent. For this, an experimental design with three factors was used: polylactic acid content, coupling agent content, and temperature profile of the blown extrusion. It was found that the three factors generated significant differences on the response variables of tensile mechanical properties individually as in their triple interaction. Differential scanning calorimetry (DSC was used by understanding the behavior of thermal properties of TPS/PLA blends with and without coupling agent, finding similar results between both. From this, the combination with 28% polylactic acid, 0.87% coupling agent, and 155.75°C temperature profile permitted the obtaining of a material with outstanding mechanical properties and offered advantages from the economic point of view.

  10. Effect of gamma irradiation on physicochemical properties of commercial poly(lactic acid) clamshell for food packaging

    Science.gov (United States)

    Madera-Santana, Tomás J.; Meléndrez, R.; González-García, Gerardo; Quintana-Owen, Patricia; Pillai, Suresh D.

    2016-06-01

    Poly(lactic acid) (PLA) is a well-known biodegradable polymer with strong potential application in food packaging industry. In this paper, samples of PLA clamshell for tomatoes packaging were exposed with 60CO γ-ray's source (1.33 MeV) at different dose levels (0, 10, 60, 150, 300, and 600 kGy), at room temperature and in presence of air. The physicochemical properties of neat PLA and sample exposed to gamma irradiation were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and tensile measurements. Results show as the dose increases, the molecular weight (Mw), melting temperature (Tm), tensile strength and elongation at break decreased. However, the tensile modulus increased with increasing doses. The surface of PLA clamshells was degraded (scratches and minor cracks) when samples were exposed to doses greater than 60 kGy.

  11. Deposition of LDH on plasma treated polylactic acid to reduce water permeability

    KAUST Repository

    Bugatti, Valeria

    2013-04-01

    A simple and scalable deposition process was developed to prepare polylactic acid (PLA) coatings with enhanced water barrier properties for food packaging applications. This method based on electrostatic interactions between the positively charged layers of layered double hydroxides (LDHs) modified with ionic liquids (ILs) and the negatively charged plasma treated polylactic acid leads to homogeneous, stable, and highly durable coatings. Deposition of the LDH coatings increases the surface hydrophobicity of the neat PLA, which results to a decrease in water permeability by about 35%. © 2013 Elsevier Inc.

  12. Biochemical and Structural Insights into Enzymatic Depolymerization of Polylactic Acid and Other Polyesters by Microbial Carboxylesterases.

    Science.gov (United States)

    Hajighasemi, Mahbod; Nocek, Boguslaw P; Tchigvintsev, Anatoli; Brown, Greg; Flick, Robert; Xu, Xiaohui; Cui, Hong; Hai, Tran; Joachimiak, Andrzej; Golyshin, Peter N; Savchenko, Alexei; Edwards, Elizabeth A; Yakunin, Alexander F

    2016-06-13

    Polylactic acid (PLA) is a biodegradable polyester derived from renewable resources, which is a leading candidate for the replacement of traditional petroleum-based polymers. Since the global production of PLA is quickly growing, there is an urgent need for the development of efficient recycling technologies, which will produce lactic acid instead of CO2 as the final product. After screening 90 purified microbial α/β-hydrolases, we identified hydrolytic activity against emulsified PLA in two uncharacterized proteins, ABO2449 from Alcanivorax borkumensis and RPA1511 from Rhodopseudomonas palustris. Both enzymes were also active against emulsified polycaprolactone and other polyesters as well as against soluble α-naphthyl and p-nitrophenyl monoesters. In addition, both ABO2449 and RPA1511 catalyzed complete or extensive hydrolysis of solid PLA with the production of lactic acid monomers, dimers, and larger oligomers as products. The crystal structure of RPA1511 was determined at 2.2 Å resolution and revealed a classical α/β-hydrolase fold with a wide-open active site containing a molecule of polyethylene glycol bound near the catalytic triad Ser114-His270-Asp242. Site-directed mutagenesis of both proteins demonstrated that the catalytic triad residues are important for the hydrolysis of both monoester and polyester substrates. We also identified several residues in RPA1511 (Gln172, Leu212, Met215, Trp218, and Leu220) and ABO2449 (Phe38 and Leu152), which were not essential for activity against soluble monoesters but were found to be critical for the hydrolysis of PLA. Our results indicate that microbial carboxyl esterases can efficiently hydrolyze various polyesters making them attractive biocatalysts for plastics depolymerization and recycling. PMID:27087107

  13. Biochemical and Structural Insights into Enzymatic Depolymerization of Polylactic Acid and Other Polyesters by Microbial Carboxylesterases.

    Science.gov (United States)

    Hajighasemi, Mahbod; Nocek, Boguslaw P; Tchigvintsev, Anatoli; Brown, Greg; Flick, Robert; Xu, Xiaohui; Cui, Hong; Hai, Tran; Joachimiak, Andrzej; Golyshin, Peter N; Savchenko, Alexei; Edwards, Elizabeth A; Yakunin, Alexander F

    2016-06-13

    Polylactic acid (PLA) is a biodegradable polyester derived from renewable resources, which is a leading candidate for the replacement of traditional petroleum-based polymers. Since the global production of PLA is quickly growing, there is an urgent need for the development of efficient recycling technologies, which will produce lactic acid instead of CO2 as the final product. After screening 90 purified microbial α/β-hydrolases, we identified hydrolytic activity against emulsified PLA in two uncharacterized proteins, ABO2449 from Alcanivorax borkumensis and RPA1511 from Rhodopseudomonas palustris. Both enzymes were also active against emulsified polycaprolactone and other polyesters as well as against soluble α-naphthyl and p-nitrophenyl monoesters. In addition, both ABO2449 and RPA1511 catalyzed complete or extensive hydrolysis of solid PLA with the production of lactic acid monomers, dimers, and larger oligomers as products. The crystal structure of RPA1511 was determined at 2.2 Å resolution and revealed a classical α/β-hydrolase fold with a wide-open active site containing a molecule of polyethylene glycol bound near the catalytic triad Ser114-His270-Asp242. Site-directed mutagenesis of both proteins demonstrated that the catalytic triad residues are important for the hydrolysis of both monoester and polyester substrates. We also identified several residues in RPA1511 (Gln172, Leu212, Met215, Trp218, and Leu220) and ABO2449 (Phe38 and Leu152), which were not essential for activity against soluble monoesters but were found to be critical for the hydrolysis of PLA. Our results indicate that microbial carboxyl esterases can efficiently hydrolyze various polyesters making them attractive biocatalysts for plastics depolymerization and recycling.

  14. The effect of fiber bleaching treatment on the properties of poly(lactic acid)/oil palm empty fruit bunch fiber composites.

    Science.gov (United States)

    Rayung, Marwah; Ibrahim, Nor Azowa; Zainuddin, Norhazlin; Saad, Wan Zuhainis; Razak, Nur Inani Abdul; Chieng, Buong Woei

    2014-01-01

    In this work, biodegradable composites from poly(lactic acid) (PLA) and oil palm empty fruit bunch (OPEFB) fiber were prepared by melt blending method. Prior to mixing, the fiber was modified through bleaching treatment using hydrogen peroxide. Bleached fiber composite showed an improvement in mechanical properties as compared to untreated fiber composite due to the enhanced fiber/matrix interfacial adhesion. Interestingly, fiber bleaching treatment also improved the physical appearance of the composite. The study was extended by blending the composites with commercially available masterbatch colorant. PMID:25153628

  15. The Effect of Fiber Bleaching Treatment on the Properties of Poly(lactic acid/Oil Palm Empty Fruit Bunch Fiber Composites

    Directory of Open Access Journals (Sweden)

    Marwah Rayung

    2014-08-01

    Full Text Available In this work, biodegradable composites from poly(lactic acid (PLA and oil palm empty fruit bunch (OPEFB fiber were prepared by melt blending method. Prior to mixing, the fiber was modified through bleaching treatment using hydrogen peroxide. Bleached fiber composite showed an improvement in mechanical properties as compared to untreated fiber composite due to the enhanced fiber/matrix interfacial adhesion. Interestingly, fiber bleaching treatment also improved the physical appearance of the composite. The study was extended by blending the composites with commercially available masterbatch colorant.

  16. Optimization of a biomimetic poly-(lactic acid) ligament scaffold

    Science.gov (United States)

    Uehlin, Andrew F.

    The anterior cruciate ligament (ACL) is the most commonly injured ligament of the knee, often requiring orthopedic reconstruction using autograft or allograph tissue, both with significant disadvantages. As a result, tissue engineering an ACL replacement graft has been heavily investigated. The present study attempts to replicate the morphology and mechanical properties of the ACL using a nanomatrix composite of highly-aligned poly(lactic acid) (PLA) fibers with various surface and biochemical modifications. Additionally, this study attempts to recreate the natural mineralization gradient found at the ACL enthesis onto the scaffold, capable of inducing a favorable cellular response in vitro. Unidirectional electrospinning was used to create nanofibers of PLA, followed by an induced degradation of the nanofibers via 0.25M NaOH hydrolysis. The effects of the unidirectional electrospinning as well as the effects of NaOH hydrolysis on fiber alignment, fiber diameter, surface morphology, crystallinity, in vitro swelling, immobilization of fibrin, and mechanical properties were investigated, resulting in a modified morphology correlating to the microstructure of native ligament tissue with similar mechanical properties. Furthering the development of the PLA nanomatrix composite, a bioinkjet printer was used to immobilize nanoparticulate hydroxyapatite (HANP) on the surface of the scaffold. A series of 300pL droplets of HANP bioink were printed over a gradient pattern mimetic of (and spatially corresponding to) the mineralization gradient found over the microanatomy at the ACL enthesis. Proliferation and differentiation response of human mesenchymal stem cells (hMSCs) in vitro was assessed on a variety of conditions and combinations of the PLA nanofiber scaffold surface modifications (inclusive and exclusive of HANP, fibrin, and various time dependent NaOH treatments). It was found that a combinatory effect of the HANP gradient with fibrin on 20 minute NaOH treated PLA

  17. Deformation and structure evolution of glassy poly(lactic acid) below the glass transition temperature

    DEFF Research Database (Denmark)

    Zhou, Chengbo; Li, Hongfei; Zhang, Yao;

    2015-01-01

    Poly(lactic acid) (PLA) is a bio-based and compostable thermoplastic polyester that has rapidly evolved into a competitive commodity material over the last decade. One key bottleneck in expanding the field of application of PLA is the control of its structure and properties. Therefore, in situ in...

  18. Solution blow spun Poly(lactic acid)/Hydroxypropyl methylcellulose nanofibers with antimicrobial properties

    Science.gov (United States)

    Poly(lactic acid) (PLA) nanofibers containing hydroxypropyl methylcellulose (HPMC) and tetracycline hydrochloride (THC) were solution blow spun from two different solvents, chloroform/acetone (CA, 80:20 v/v) and 2,2,2-triflouroethanol (TFE). The diameter distribution, chemical, thermal, thermal stab...

  19. Distribution and Orientation of Carbon Fibers in Polylactic Acid Parts Produced by Fused Deposition Modeling

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; W. Gutmann, Ingomar; Koch, Thomas;

    2016-01-01

    The aim of this paper is the understanding of the fiber orientation by investigations in respect to the inner configuration of a polylactic acid matrix reinforced with short carbon fibers after a fused deposition modeling extrusion process. The final parts were analyzed by X-ray, tomography...

  20. Physical and mechanical properties of extruded poly(lactic acid)-based Paulownia elongata biocomposites

    Science.gov (United States)

    Paulownia wood flour (PWF), a byproduct of milling lumber, was tested as bio-filler with polylactic acid (PLA). Paulownia wood (PW) shavings were milled and separated into particle fractions and then blended with PLA with a single screw extruder. Mechanical and thermal properties were tested. Dif...

  1. Antimicrobial activity of nisin incorporated in pectin and polylactic acid composite films against Listeria monocytogenes

    Science.gov (United States)

    Extruded composite films from 20% pectin and 80% polylactic acids (PLA) were developed and nisin was loaded into films by a diffusion post extrusion. Inhibitory activities of the films against Listeria monocytogenes were evaluated in brain heart infusion (BHI) broth, liquid egg white and orange juic...

  2. 聚乳酸在血管支架中的应用及研究进展%Research advances of polylactic acid and its application in vascular stents

    Institute of Scientific and Technical Information of China (English)

    毛岳峰; 朱晒红; 王国慧

    2008-01-01

    聚乳酸及其共聚物是一类可生物降解的高分子聚合材料,不仅具有优良的机械性能和化学稳定性,还具备良好的生物相容性、可吸收性以及可降解性,因此被广泛应用于医学领域.主要介绍聚乳酸在血管支架方面的应用和研究进展.%Polylactic acid (PLA) and its copolymer are biodegradable polymer materials which are widely used in the medical field because of their excellent mechanical properties, chemical stability, good biocompatibility, and biodegradability. In this paper, research advances in the study on polylactic acid and its application in vascular stent are discussed.

  3. Dual responsive polymeric nanoparticles prepared by direct functionalization of polylactic acid-based polymers via graft-from ring opening metathesis polymerization.

    Science.gov (United States)

    Veccharelli, Kate M; Tong, Venus K; Young, Jennifer L; Yang, Jerry; Gianneschi, Nathan C

    2016-01-11

    Polylactic acid (PLA) has found widespread use in plastics and in biomedical applications due to its biodegradability into natural benign products. However, PLA-based materials remain limited in usefulness due to difficulty of incorporating functional groups into the polymer backbone. In this paper, we report a strategy for PLA functionalization that establishes the preparation of highly derivatized materials in which ring opening metathesis polymerization (ROMP) is employed as a graft-from polymerization technique utilizing a norbornene-modified handle incorporated into the PLA backbone. As a demonstration of this new synthetic methodology, a PLA-derived nanoparticle bearing imidazole units protected with a photolabile group was prepared. The morphology of this material could be controllably altered in response to exposure of UV light or acidic pH as a stimulus. We anticipate that this graft-from approach to derivatization of PLA could find broad use in the development of modified, biodegradable PLA-based materials.

  4. A new approach in compatibilization of the poly(lactic acid)/thermoplastic starch (PLA/TPS) blends.

    Science.gov (United States)

    Akrami, Marzieh; Ghasemi, Ismaeil; Azizi, Hamed; Karrabi, Mohammad; Seyedabadi, Mohammad

    2016-06-25

    In this study, a new compatibilizer was synthesized to improve the compatibility of the poly(lactic acid)/thermoplastic starch blends. The compatibilizer was based on maleic anhydride grafted polyethylene glycol grafted starch (mPEG-g-St), and was characterized using Fourier transform infrared spectroscopy (FTIR), dynamic mechanical thermal analysis (DMTA) and back titration techniques. The results indicated successful accomplishment of the designed reactions and formation of a starch cored structure with many connections to m-PEG chains. To assess the performance of synthesized compatibilizer, several PLA/TPS blends were prepared using an internal mixer. Consequently, their morphology, dynamic-mechanical behavior, crystallization and mechanical properties were studied. The compatibilizer enhanced interfacial adhesion, possibly due to interaction between free end carboxylic acid groups of compatibilizer and active groups of TPS and PLA phases. In addition, biodegradability of the samples was evaluated by various methods consisting of weight loss, FTIR-ATR analysis and morphology. The results revealed no considerable effect of compatibilizer on biodegradability of samples. PMID:27083816

  5. Polylactic Acid-Based Polymer Blends for Durable Applications

    Science.gov (United States)

    Finniss, Adam

    There has been considerable scientific interest in both research and commercial communities as of late in the area of biologically based or sourced plastics. As the consumption of petroleum rises and concerns about climate change increase, this field is likely to grow even larger. One bioplastic that has received a great deal of attention is polylactic acid (PLA). In the past, this material was used mainly in medical or specialty applications, but advancements in manufacturing have led to a desire to use PLA more widely, especially in durable applications. Unfortunately, PLA has several drawbacks that hinder more widespread usage of the material as a durable item: it has low ductility and impact strength in bulk applications, along with poor stability in the face of heat, humidity or liquid media. To combat these deficiencies, a number of techniques were investigated. Samples were annealed to create crystalline domains that would improve mechanical properties and reduce diffusion, blended with graphene to create barriers to diffusion throughout the material, or compounded with a polycarbonate (PC) polymer phase to protect the PLA phase and to enhance the mechanical properties of the blend. If a material containing biologically sourced components with good mechanical properties can be created, it would be desirable for durable uses such as electronics components or as an automotive grade resin. Crystallization experiments were carried out in a differential scanning calorimeter to determine the effects of heat treatment and additives on the rather slow crystallization kinetics of PLA polymer. It was determined that the blending in of the PC phase did not significantly alter the kinetics or mechanism of crystal growth. The addition of graphene to any PC/PLA formulation served as a nucleating agent which speeded up the crystallization kinetics markedly, in some cases by several orders of magnitude. Results obtained from these experiments were internally consistent

  6. XPS and wettability characterization of modified poly(lactic acid) and poly(lactic/glycolic acid) films.

    Science.gov (United States)

    Kiss, E; Bertóti, I; Vargha-Butler, E I

    2002-01-01

    Poly(lactic acid) (PLA) and poly(lactic/glycolic acid) copolymers (PLGA) are biodegradable drug carriers of great importance, although successful pharmaceutical application requires adjustment of the surface properties of the polymeric drug delivery system to be compatible with the biological environment. For that reason, reduction of the original hydrophobicity of the PLA or PLGA surfaces was performed by applying a hydrophilic polymer poly(ethylene oxide) (PEO) with the aim to improve biocompatibility of the original polymer. PEO-containing surfaces were prepared by incorporation of block copolymeric surfactants, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (Pluronic), into the hydrophobic surface. Films of polymer blends from PLA or PLGA (with lactic/glycolic acid ratios of 75/25 and 50/50) and from Pluronics (PE6800, PE6400, and PE6100) were obtained by the solvent casting method, applying the Pluronics at different concentrations between 1 and 9.1% w/w. Wettability was measured to monitor the change in surface hydrophobicity, while X-ray photoelectron spectroscopy (XPS) was applied to determine the composition and chemical structure of the polymer surface and its change with surface modification. Substantial reduction of surface hydrophobicity was achieved on both the PLA homopolymer and the PLGA copolymers by applying the Pluronics at various concentrations. In accordance with the wettability changes the accumulation of Pluronics in the surface layer was greatly affected by the initial hydrophobicity of the polymer, namely, by the lactide content of the copolymer. The extent of surface modification was also found to be dependent on the type of blended Pluronics. Surface activity of the modifying Pluronic component was interpreted by using the solubility parameters. PMID:16290340

  7. A CRADLE TO GATE LIFE CYCLE ANALYSIS OF THE BIOPOLYMER POLYLACTIC ACID: LOOKING BEYOND GLOBAL WARMING AND FOSSIL FUEL USE

    Science.gov (United States)

    Derived from corn, the biopolymer polylactic acid (PLA) has recently emerged in the marketplace and is advertised as a sustainable alternative to petroleum-based polymers. Research into the environmental implications of biobased production has focused primarily on global warming...

  8. Clinical performance of a dermal filler containing natural glycolic Acid and a polylactic Acid polymer: results of a clinical trial in human immunodeficiency virus subjects with facial lipoatrophy.

    Science.gov (United States)

    Tagle, Jorge M; Macchetto, Pedro Cervantes; Durán Páramo, Rosa Margarita

    2010-02-01

    Lipoatrophy is a condition that affects certain individuals, most commonly those who are infected with the human immunodeficiency virus.(1-3) Injectable fillers are used for the treatment of these dermal contour deformities to smooth dermal depressions formed by the loss of volume. These dermal fillers (also known as soft tissue augmentation devices) can correct contour deformities caused by lipoatrophy in patients who are human immunodeficiency virus positive or negative. The product used in this study is a patented, second-generation, injectable, dermal collagen stimulator that combines glycolic acid and polylactic acid. The glycolic acid used is not a polymer, but rather an acid derived from sugar cane. Its chemical structure corresponds to that of an alpha-hydroxy acid. Glycolic acid is a well-characterized agent that is present in a number of cosmetic products. Polylactic acid is a synthetic, biocompatible, biodegradable, inert, synthetic polymer from the poly a-hydroxy-acid family that is believed to stimulate fibroblasts to produce more collagen, thus increasing facial volume. Together, polylactic acid and glycolic acid act in concert to 1) stimulate collagen production and 2) hydrate the outer layers of the skin. A multicenter, clinical investigation authorized by the Mexican Secretariat of Health was conducted between September 20, 2002, and September 19, 2004. This clinical study was conducted in male patients between 32 and 60 years of age with lipoatrophy as a result of highly active antiretroviral therapy for human immunodeficiency virus infection. The study objective was to measure the improvement of contour deformities after the injection of a dermal collagen stimulator containing glycolic acid and polylactic acid. In addition to safety, this dermal filler was assessed when used to correct volume deformities caused by lipoatrophy in subjects who are human immunodeficiency virus positive. Thirty male subjects participated and were treated as follows

  9. Preparation of etoposide Polylactic Acid Microspheres%依托泊苷聚乳酸微球的制备

    Institute of Scientific and Technical Information of China (English)

    姜素芳; 张云坤; 周学军

    2011-01-01

    目的::用生物可降解材料聚乳酸制备依托泊苷微球,并对其体外释药特性进行研究.方法:采用乳化-溶剂扩散法制备依托泊苷聚乳酸微球,通过正交试验确定最佳处方工艺;采用紫外分光光度法测定微球载药量、包封率和体外药物释放,利用光学显微镜观察微球形态和粒径分布.结果:所得微球外观圆整,平均粒径为12.87 μm,载药量为14.79%,药物包封率为61.09%,体外释药符合Higuchi方程.结论:依托泊苷聚乳酸微球制备工艺稳定,体外释药符合长效制剂特征.%Objective To prepare etoposide microspheres using thg biodegradable meterials-polylactic acid and to study its release characteristics in vitro. Methods The polylactic acid microspheres were prepared by emulsion-solvent diffusion method and the orthogonal test design was used to optimize the formulation and technology .The drug-loading,emcapsulation and release in vitro were determined by ultraviolet spectrophotometry and the appearance and particle size of microspheres was observed by light microscope. Results The shape of etoposide microspheres was spherical with mean particle size of 12.87 ujn.The drug loading and encapsulation efficiency were 14.79% and 61.09%, respectively. The in vitro release characteristics of microspheres was found to agree with Higuchi equation. Conclusion The technology of preparation was successful and etoposide polylactic acid micropheres showed significant sustained release.

  10. Chitosan grafted low molecular weight polylactic acid for protein encapsulation and burst effect reduction.

    Science.gov (United States)

    Di Martino, Antonio; Kucharczyk, Pavel; Zednik, Jiri; Sedlarik, Vladimir

    2015-12-30

    Chitosan and chitosan-grafted polylactic acid as a matrix for BSA encapsulation in a nanoparticle structure were prepared through a polyelectrolyte complexation method with dextran sulfate. Polylactic acid was synthetized via a polycondensation reaction using the non-metal-based initiator methanesulfonic acid and grafted to the chitosan backbone by a coupling reaction, with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide as the condensing agent. The effect of concentration of the polymer matrix utilized herein on particle diameter, ζ-potential, encapsulation efficiency, and the release kinetic of the model protein bovine serum albumin at differing pH levels was investigated. The influence of pH and ionic strength on the behavior of the nanoparticles prepared was also researched. Results showed that grafting polylactic acid to chitosan chains reduced the initial burst effect in the kinetics of BSA release from the structure of the nanoparticles. Furthermore, a rise in encapsulation efficiency of the bovine serum albumin and diminishment in nanoparticle diameter were observed due to chitosan modification. The results suggest that both polymers actually show appreciable encapsulation efficiency; and release rate of BSA. CS-g-PLA is more suitable than unmodified CS as a carrier for controlled protein delivery.

  11. Polylactic Acid-Based Polymer Blends for Durable Applications

    Science.gov (United States)

    Finniss, Adam

    There has been considerable scientific interest in both research and commercial communities as of late in the area of biologically based or sourced plastics. As the consumption of petroleum rises and concerns about climate change increase, this field is likely to grow even larger. One bioplastic that has received a great deal of attention is polylactic acid (PLA). In the past, this material was used mainly in medical or specialty applications, but advancements in manufacturing have led to a desire to use PLA more widely, especially in durable applications. Unfortunately, PLA has several drawbacks that hinder more widespread usage of the material as a durable item: it has low ductility and impact strength in bulk applications, along with poor stability in the face of heat, humidity or liquid media. To combat these deficiencies, a number of techniques were investigated. Samples were annealed to create crystalline domains that would improve mechanical properties and reduce diffusion, blended with graphene to create barriers to diffusion throughout the material, or compounded with a polycarbonate (PC) polymer phase to protect the PLA phase and to enhance the mechanical properties of the blend. If a material containing biologically sourced components with good mechanical properties can be created, it would be desirable for durable uses such as electronics components or as an automotive grade resin. Crystallization experiments were carried out in a differential scanning calorimeter to determine the effects of heat treatment and additives on the rather slow crystallization kinetics of PLA polymer. It was determined that the blending in of the PC phase did not significantly alter the kinetics or mechanism of crystal growth. The addition of graphene to any PC/PLA formulation served as a nucleating agent which speeded up the crystallization kinetics markedly, in some cases by several orders of magnitude. Results obtained from these experiments were internally consistent

  12. Preparation of poly(lactic acid) composite hollow spheres containing calcium carbonates.

    Science.gov (United States)

    Maeda, Hirotaka; Kasuga, Toshihiro

    2006-07-01

    Poly(lactic acid) composite hollow spheres containing calcium carbonate were prepared by oil-in-water emulsion evaporation to develop injectable bone substitutes incorporated with cells. The spheres were approximately 1.2mm in diameter and had a shell with a thickness in the range of 50-150microm. The hollow in the spheres was presumed to be formed by CO(2) gas generated by the decomposition of vaterite used as a starting material. An open channel approximately 800microm in diameter was formed in the spheres by chemical etching utilizing the rapid dissolution of poly(lactic acid) at the thin portion of the shell. Cells could migrate into the hollow spheres through the open channel and attach to the inner surface. PMID:16765880

  13. Preparation, Mechanical, and Thermal Properties of Biodegradable Polyesters/Poly(Lactic Acid Blends

    Directory of Open Access Journals (Sweden)

    Peng Zhao

    2010-01-01

    Full Text Available Series of biodegradable polyesters poly(butylene adipate (PBA, poly(butylene succinate (PBS, and poly(butylene adipate-co-butylene terephthalate (PBAT were synthesized successfully by melt polycondensation. The polyesters were characterized by Fourier transform infrared spectroscopy (FTIR, 1H-NMR, differential scanning calorimetry (DSC, and gel permeation chromatography (GPC, respectively. The blends of poly(lactic acid (PLA and biodegradable polyester were prepared using a twin screw extruder. PBAT, PBS, or PBA can be homogenously dispersed in PLA matrix at a low content (5–20 wt%, yielding the blends with much higher elongation at break than homo-PLA. DSC analysis shows that the isothermal and nonisothermal crystallizabilities of PLA component are promoted in the presence of a small amount of PBAT.

  14. Poly(lactic acid)/Carbon Nanotube Fibers as Novel Platforms for Glucose Biosensors

    OpenAIRE

    Valtencir Zucolotto; Eliton Souto Medeiros; Luiz Henrique Capparelli Mattoso; Juliano Elvis Oliveira

    2012-01-01

    The focus of this paper is the development and investigation of properties of new nanostructured architecture for biosensors applications. Highly porous nanocomposite fibers were developed for use as active materials in biosensors. The nanocomposites comprised poly(lactic acid)(PLA)/multi-walled carbon nanotube (MWCNT) fibers obtained via solution-blow spinning onto indium tin oxide (ITO) electrodes. The electrocatalytic properties of nanocomposite-modified ITO electrodes were investigated to...

  15. Preparation and characterization of interpenetrating networks based on polyacrylates and poly(lactic acid)

    OpenAIRE

    H. Kaczmarek; I. Vukovic-Kwiatkowska

    2012-01-01

    Three different, multifunctional acrylic monomers were photopolymerized in a matrix of poly(lactic acid), PLA, using 2-hydroxy-2-methyl-1-phenyl-propan-1-one as a photoinitiator. The kinetics of the photopolymerization of monomers in PLA, studied with Fourier Transform Infrared Spectroscopy, has been compared to analogous processes of pure monomers under the same conditions (room temperature, air atmosphere). Additionally, poly(ethylene glycol) was added to acrylate/PLA blends as plasticizer....

  16. Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

    OpenAIRE

    Chern Chiet Eng; Nor Azowa Ibrahim; Norhazlin Zainuddin; Hidayah Ariffin; Wan Md Zin Wan Yunus; Yoon Yee Then; Cher Chean Teh

    2013-01-01

    The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA)/Polycaprolactone (PCL) blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM),...

  17. Barrier Properties of Polylactic Acid in Cellulose Based Packages Using Montmorillonite as Filler

    OpenAIRE

    Daniela Sánchez Aldana; Eduardo Duarte Villa; Miguel De Dios Hernández; Guillermo González Sánchez; Quintín Rascón Cruz; Sergio Flores Gallardo; Hilda Piñon Castillo; Lourdes Ballinas Casarrubias

    2014-01-01

    Polylactic acid (PLA) and montmorillonite (CB) as filler were studied as coatings for cellulose based packages. Amorphous (AM) and semi crystalline (SC) PLA were used at different concentrations according to a 2 × 6 × 3 full factorial experimental design. CB loading was three concentrations and coating was performed by casting. Contact angle (CA), water vapor (WVP) and grease permeabilities were measured for each resultant package and were compared to commercial materials (Glassine Paper, Gre...

  18. Synthesis of high molecular weight polylactic acid from aqueous lactic acid co-catalyzed by tin(II)chloride dihydrate and succinic anhydride

    Institute of Scientific and Technical Information of China (English)

    LEI Ziqiang; BAI Yanbin; WANG Shoufeng

    2005-01-01

    Polylactic acid was synthesized from commercial available cheap aqueous lactic acid (85%―90% w/w) using succinic anhydride and SnCl2·2H2O as catalyst in the absence of organic solvents. As a result, polylactic acid with a molecular weight of 60000 was prepared in 10 h. The new procedure is much simple, cheap and outstanding in that the start material is aqueous lactic acid; the catalytic system is environmentally benign.

  19. Preparation and characterization of dry method esterified starch/polylactic acid composite materials.

    Science.gov (United States)

    Zuo, Yingfeng; Gu, Jiyou; Yang, Long; Qiao, Zhibang; Tan, Haiyan; Zhang, Yanhua

    2014-03-01

    Corn starch and maleic anhydride were synthesized from a maleic anhydride esterified starch by dry method. Fourier transform infrared spectroscopy (FTIR) was used for the qualitative analysis of the esterified starches. The reaction efficiency of dry method esterified starch reached 92.34%. The dry method esterified starch was blended with polylactic acid (PLA), and the mixture was melted and extruded to produce the esterified starch/polylactic acid (ES/PLA) composites. The degree of crystallinity of the ES/PLA was lower than that of the NS/PLA, indicating that the relative dependence between these two components of starch and polylactic acid was enhanced. Scanning electron microscopy (SEM) indicated that the dry method esterified starch increased the two-phase interface compatibility of the composites, thereby improving the tensile strength, bending strength, and elongation at break of the ES/PLA composite. The introduction of a hydrophobic ester bond and increase in interface compatibility led to an increase in ES/PLA water resistance. Melt index determination results showed that starch esterification modification had improved the melt flow properties of starch/PLA composite material. Strain scanning also showed that the compatibility of ES/PLA was increased. While frequency scanning showed that the storage modulus and complex viscosity of ES/PLA was less than that of NS/PLA. PMID:24315947

  20. Additive Manufacturing and Characterization of Polylactic Acid (PLA) Composites Containing Metal Reinforcements

    Science.gov (United States)

    Kuentz, Lily; Salem, Anton; Singh, M.; Halbig, M. C.; Salem, J. A.

    2016-01-01

    Additive manufacturing of polymeric systems using 3D printing has become quite popular recently due to rapid growth and availability of low cost and open source 3D printers. Two widely used 3D printing filaments are based on polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) systems. PLA is much more environmentally friendly in comparison to ABS since it is made from renewable resources such as corn, sugarcane, and other starches as precursors. Recently, polylactic acid-based metal powder containing composite filaments have emerged which could be utilized for multifunctional applications. The composite filaments have higher density than pure PLA, and the majority of the materials volume is made up of polylactic acid. In order to utilize functionalities of composite filaments, printing behavior and properties of 3-D printed composites need to be characterized and compared with the pure PLA materials. In this study, pure PLA and composite specimens with different metallic reinforcements (Copper, Bronze, Tungsten, Iron, etc) were 3D printed at various layer heights and resulting microstructures and properties were characterized. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) behavior of filaments with different reinforcements were studied. The microscopy results show an increase in porosity between 3-D printed regular PLA and the metal composite PLA samples, which could produce weaker mechanical properties in the metal composite materials. Tensile strength and fracture toughness behavior of specimens as a function of print layer height will be presented.

  1. Preparation and characterization of dry method esterified starch/polylactic acid composite materials.

    Science.gov (United States)

    Zuo, Yingfeng; Gu, Jiyou; Yang, Long; Qiao, Zhibang; Tan, Haiyan; Zhang, Yanhua

    2014-03-01

    Corn starch and maleic anhydride were synthesized from a maleic anhydride esterified starch by dry method. Fourier transform infrared spectroscopy (FTIR) was used for the qualitative analysis of the esterified starches. The reaction efficiency of dry method esterified starch reached 92.34%. The dry method esterified starch was blended with polylactic acid (PLA), and the mixture was melted and extruded to produce the esterified starch/polylactic acid (ES/PLA) composites. The degree of crystallinity of the ES/PLA was lower than that of the NS/PLA, indicating that the relative dependence between these two components of starch and polylactic acid was enhanced. Scanning electron microscopy (SEM) indicated that the dry method esterified starch increased the two-phase interface compatibility of the composites, thereby improving the tensile strength, bending strength, and elongation at break of the ES/PLA composite. The introduction of a hydrophobic ester bond and increase in interface compatibility led to an increase in ES/PLA water resistance. Melt index determination results showed that starch esterification modification had improved the melt flow properties of starch/PLA composite material. Strain scanning also showed that the compatibility of ES/PLA was increased. While frequency scanning showed that the storage modulus and complex viscosity of ES/PLA was less than that of NS/PLA.

  2. Poly(Lactic Acid) Hemodialysis Membranes with Poly(Lactic Acid)-block-Poly(2-Hydroxyethyl Methacrylate) Copolymer As Additive: Preparation, Characterization, and Performance.

    Science.gov (United States)

    Zhu, Lijing; Liu, Fu; Yu, Xuemin; Xue, Lixin

    2015-08-19

    Poly(lactic acid) (PLA) hemodialysis membranes with enhanced antifouling capability and hemocompatibility were developed using poly(lactic acid)-block-poly(2-hydroxyethyl methacrylate) (PLA-PHEMA) copolymers as the blending additive. PLA-PHEMA block copolymers were synthesized via reversible addition-fragmentation (RAFT) polymerization from aminolyzed PLA. Gel permeation chromatography (GPC) and (1)H-nuclear magnetic resonance ((1)H NMR) were applied to characterize the synthesized products. By blending PLA with the amphiphilic block copolymer, PLA/PLA-PHEMA membranes were prepared by nonsolvent induced phase separation (NIPS) method. Their chemistry and structure were characterized with X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and atomic force microscopy (AFM). The results revealed that PLA/PLA-PHEMA membranes with high PLA-PHEMA contents exhibited enhanced hydrophilicity, water permeability, antifouling and hemocompatibility. Especially, when the PLA-PHEMA concentration was 15 wt %, the water flux of the modified membrane was about 236 L m(-2) h(-1). Its urea and creatinine clearance was more than 0.70 mL/min, lysozyme clearance was about 0.50 mL/min, BSA clearance was as less as 0.31 mL/min. All the results suggest that PLA-PHEMA copolymers had served as effective agents for optimizing the property of PLA-based membrane for hemodialysis applications. PMID:26222398

  3. Antimicrobial activity of allyl isothiocyanate used to coat biodegradable composite films as affected by storage and handling conditions

    Science.gov (United States)

    We evaluated the effects of storage and handling conditions on the antimicrobial activity of biodegradable composite films (polylactic acid and sugar beet pulp) coated with allyl isothiocyanate (AIT). Polylactic acid (PLA) and chitosan were incorporated with AIT and coated on one side of the film. T...

  4. Τhe effect of silica nanoparticles on the thermomechanical properties and degradation behavior of polylactic acid.

    Science.gov (United States)

    Georgiopoulos, P; Kontou, E; Meristoudi, A; Pispas, S; Chatzinikolaidou, M

    2014-11-01

    In this work a series of polylactic acid/SiO2 nanocomposites have been prepared by a melt mixing procedure. The dispersion quality was examined by scanning electron microscopy. To study the degradation behavior of the polylactic acid/nanocomposites prepared, the samples were immersed in a buffer solution at a temperature of 37℃ with a pH of 7.4 for a time period of up to 23 weeks. These conditions simulate those in the human body, appropriate in medical applications. In order to assess their suitability in biomedical applications, we investigated the biocompatibility of these materials in terms of cell viability, growth, and morphology. A good initial cell adhesion has been detected, supporting their potential use in bone tissue engineering applications. The hydrolytic degradation of polylactic acid, under the prescribed conditions, was studied by the molecular weight reduction in terms of size exclusion chromatography, whereas the progress of thermal stability of polylactic acid and polylactic acid/nanocomposites during aging was tested by thermogravimetric analysis. The evolution of the materials' thermomechanical properties during aging was studied by differential scanning calorimetry, dynamic mechanical analysis, and tensile testing. The crystallization behavior in polylactic acid and the way it is affected by the presence of nanofillers during degradation procedure has been studied and values of 44% crystallinity increment have been found. At the specific aging conditions studied, silica nanoparticles accelerate the degradability of polylactic acid, having a higher impact on Young's modulus, under the specified aging conditions, for 7 weeks and hereafter this acceleration is retarded, due to the crystallinity increment, as a result of the molecular weight reduction.

  5. Preparation and characterization of composites based on poly(lactic acid) and CaCO{sub 3} nanofiller

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Janaína Fernandes; Silva, Ana Lúcia N. da, E-mail: janamoreno.quim@gmail.com, E-mail: ananazareth@ima.ufrj.br [Instituto de Macromoléculas Professora Eloisa Mano - IMA/UFRJ – Brasil, Rio de Janeiro – RJ (Brazil); Silva, Antonio Henrique Monteiro da Fonseca T. da, E-mail: antoniohmfts@id.uff.br [Departamento Agrícola e Meio Ambiente – UFF – Brasil, Niterói – RJ (Brazil); Sousa, Ana Maria F. de, E-mail: ana.furtado.souza@gmail.com [Instituto de Química da Universidade - IQ/UERJ – Brasil, Rio de Janeiro – RJ (Brazil)

    2015-05-22

    In recent years, extensive studies have been conducted on the study of the poly(lactic acid) (PLA) properties, because of its being a typical biobased and biodegradable polymer, with good mechanical properties. However, its toughness and gas barrier properties are not satisfactory and can be improved by the addition of nanofillers, such as calcium carbonate (n-CaCO{sub 3}). The present work PLA composites with nano-sized precipitated calcium carbonate (n-NPCC) were prepared by melt extrusion. Thermal, mechanical and flow properties of the composites were evaluated by using a factorial design.The results showed that the addition of the nanofiller in the PLA matrix didn’t improve thethermal and mechanical properties of the matrix significantly. This behavior is probably due to the presence of the stearic acid that is coating on the n-NPCC particles, resulting in a weak polymer-particle interaction. Beyond this, it was also observed a decrease in MFI of the composites when nanofiller was added and at a higher screw speed.

  6. Mechanical and moisture barrier properties of titanium dioxide nanoparticles and halloysite nanotubes reinforced polylactic acid (PLA)

    Science.gov (United States)

    Alberton, J.; Martelli, S. M.; Fakhouri, F. M.; Soldi, V.

    2014-08-01

    Polylactic acid (PLA) has been larger used in biomedical field due to its low toxicity and biodegradability. The aim of this study was to produce PLLA nanocomposites, by melt extrusion, containing Halloysite nanotubes (HNT) and/or titanium dioxide (TiO2) nanoparticles. Immediately after drying, PLLA was mechanically homogenized with the nanofillers and then melt blended using a single screw extruder (L/D = 30) at a speed of 110 rpm, with three heating zones in which the following temperatures were maintained: 150, 150 and 160°C (AX Plasticos model AX14 LD30). The film samples were obtained by compression molding in a press with a temperature profile of 235 ± 5°C for 2.5 min, after pressing, films were cooled up to room temperature. The mechanical tests were performed according to ASTM D882-09 and the water vapor permeability (WVP) was measured according to ASTM E-96, in triplicate. The tensile properties indicated that the modulus was improved with increased TiO2 content up to 1g/100g PLLA. The Young's modulus (YM) of the PLA was increased from 3047 MPa to 3222 MPa with the addition of 1g TiO2/100g PLLA. The tensile strength (TS) of films increases with the TiO2 content. In both cases, the YM and TS are achieved at the 1% content of TiO2 and is due to the reinforcing effect of nanoparticles. Pristine PLA showed a strain at break (SB) of 3.56%, while the SB of nanocomposites were significant lower, for instance the SB of composite containing 7.5 g HNT/100g PLLA was around 1.90 %. The WVP of samples was increased by increasing the nano filler content. It should be expected that an increase of nanofiller content would decrease the mass transfer of water molecules throughout the samples due to the increase in the way water molecules will have to cross to permeate the material. However, this was not observed. Therefore, this result can be explained considering the molecular structure of both fillers, which contain several hydroxyl groups in the surface, making the

  7. Superabsorbent biphasic system based on poly(lactic acid) and poly(acrylic acid)

    Science.gov (United States)

    Sartore, Luciana; Pandini, Stefano; Baldi, Francesco; Bignotti, Fabio

    2016-05-01

    In this research work, biocomposites based on crosslinked particles of poly(acrylic acid), commonly used as superabsorbent polymer (SAP), and poly-L-lactic acid (PLLA) were developed to elucidate the role of the filler (i.e., polymeric crosslinked particles) on the overall physico-mechanical behavior and to obtain superabsorbent thermoplastic products. Samples prepared by melt-blending of components in different ratios showed a biphasic system with a regular distribution of particles, with diameter ranging from 5 to 10 μm, within the PLLA polymeric matrix. The polymeric biphasic system, coded PLASA i.e. superabsorbent poly(lactic acid), showed excellent swelling properties, demonstrating that cross-linked particles retain their superabsorbent ability, as in their free counterparts, even if distributed in a thermoplastic polymeric matrix. The thermal characteristics of the biocomposites evidence enhanced thermal stability in comparison with neat PLLA and also mechanical properties are markedly modified by addition of crosslinked particles which induce regular stiffening effect. Furthermore, in aqueous environments the particles swell and are leached from PLLA matrix generating very high porosity. These new open-pore PLLA foams, produced in absence of organic solvents and chemical foaming agents, with good physico-mechanical properties appear very promising for several applications, for instance in tissue engineering for scaffold production.

  8. Effects of gas atmospheres on poly(lactic acid) film in acrylic acid plasma treatment

    Science.gov (United States)

    Zhao, Yun; Fina, Alberto; Venturello, Alberto; Geobaldo, Francesco

    2013-10-01

    Plasma polymerized acrylic acid (AA) coatings were deposited on poly(lactic acid) (PLA) films in various gas atmospheres during the pre-treatment of PLA and the deposition of AA, respectively. Therefore, this work was twofold: the argon pretreated PLA films followed by a deposition in argon were investigated against the mixture of argon and oxygen pretreated ones under the same deposition conditions; the plasma deposition of AA operating in different atmospheres (argon, oxygen and nitrogen) was employed to modify the pretreated PLA in oxygen. Chemical and physical changes on the plasma-treated surfaces were examined using contact angle, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and attenuated total reflection infrared (ATR-FTIR) analysis. The results showed that the discharge gas can have a significant influence on the chemical composition of the PLA surfaces: oxygen plasmas introduced oxygen-containing groups in company with surface etching in pretreatment and deposition, while argon discharges was able to achieve much better hydrophilic behavior and high retention ratio of poly(acrylic acid) (PAA) coating before and after washing in water.

  9. Effects of gas atmospheres on poly(lactic acid) film in acrylic acid plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yun, E-mail: yun.zhaotju@yahoo.com [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Fina, Alberto [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino – sede di Alessandria, V. T. Michel 5, 15121 Alessandria (Italy); Venturello, Alberto; Geobaldo, Francesco [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy)

    2013-10-15

    Plasma polymerized acrylic acid (AA) coatings were deposited on poly(lactic acid) (PLA) films in various gas atmospheres during the pre-treatment of PLA and the deposition of AA, respectively. Therefore, this work was twofold: the argon pretreated PLA films followed by a deposition in argon were investigated against the mixture of argon and oxygen pretreated ones under the same deposition conditions; the plasma deposition of AA operating in different atmospheres (argon, oxygen and nitrogen) was employed to modify the pretreated PLA in oxygen. Chemical and physical changes on the plasma-treated surfaces were examined using contact angle, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and attenuated total reflection infrared (ATR-FTIR) analysis. The results showed that the discharge gas can have a significant influence on the chemical composition of the PLA surfaces: oxygen plasmas introduced oxygen-containing groups in company with surface etching in pretreatment and deposition, while argon discharges was able to achieve much better hydrophilic behavior and high retention ratio of poly(acrylic acid) (PAA) coating before and after washing in water.

  10. Research progress of toughening modification of polylactic acid%聚乳酸增韧改性研究进展

    Institute of Scientific and Technical Information of China (English)

    肖伟娜; 黄雪; 冯光炷; 尹国强; 崔英德

    2011-01-01

    Polylactic acid ( PLA ) is widely used in agriculture, packaging, medicine and health care because it is a biocompatible, biodegradable and bioabsorbable polymer and has fine mechanical property. But it is hard and brittle and has poor pliability because it has a high glass transition temperature. Thus, it has to be modified to enhance its pliability to improve handling and application.In this paper, the recent research progress of toughening modification of PLA via copolymerization,cross-linking, and blending is reviewed.%聚乳酸因具有良好生物相容性、生物降解性、生物可吸收性以及优良的力学性能,在农业,食品包装、医疗卫生等领域得到了广泛应用,但因其玻璃化转变温度较高、性脆、柔韧性差,需通过增韧改性以提高其加工和应用性能.本文综述了聚乳酸通过共聚、交联、共混等改性方法增加柔韧性的最新研究进展.

  11. Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding.

    Science.gov (United States)

    Mi, Hao-Yang; Salick, Max R; Jing, Xin; Jacques, Brianna R; Crone, Wendy C; Peng, Xiang-Fang; Turng, Lih-Sheng

    2013-12-01

    Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications. PMID:24094186

  12. Effect of hydrion evolution by polylactic-co-glycolic acid coating on degradation rate of pure iron.

    Science.gov (United States)

    Wu, Jingyao; Lu, Xi; Tan, Lili; Zhang, Bingchun; Yang, Ke

    2013-10-01

    For biodegradable iron coronary stents, the major problem is the low degradation rate in body environment. In this study, a new strategy was proposed to increase the degradation rate of iron in vitro. The hydrion evolution was intended to be introduced into the degradation system to increase the degradation rate. To realize this strategy, polylactic-co-glycolic acid (PLGA) was coated onto the surface of pure iron. The degradation process and mechanism of pure iron coated with PLGA were investigated. The results showed that iron coated with PLGA exhibited higher degradation rate in the static immersion test all along. With the degradation of PLGA, the oligomers of PLGA could release abundant H(+) which could dissolve the ferrous oxide to make the electrolyte and oxygen to reach the surface of iron again and simultaneity trigger the hydrion evolution at the middle stage of the degradation. The study also revealed that the solution ions failed to permeate the PLGA coating and the deposition of calcium and phosphorus in the degradation layer was inhibited which further enhanced the degradation.

  13. Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding.

    Science.gov (United States)

    Mi, Hao-Yang; Salick, Max R; Jing, Xin; Jacques, Brianna R; Crone, Wendy C; Peng, Xiang-Fang; Turng, Lih-Sheng

    2013-12-01

    Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications.

  14. Tailoring bulk mechanical properties of 3D printed objects of polylactic acid varying internal micro-architecture

    Science.gov (United States)

    Malinauskas, Mangirdas; Skliutas, Edvinas; Jonušauskas, Linas; Mizeras, Deividas; Šešok, Andžela; Piskarskas, Algis

    2015-05-01

    Herein we present 3D Printing (3DP) fabrication of structures having internal microarchitecture and characterization of their mechanical properties. Depending on the material, geometry and fill factor, the manufactured objects mechanical performance can be tailored from "hard" to "soft." In this work we employ low-cost fused filament fabrication 3D printer enabling point-by-point structuring of poly(lactic acid) (PLA) with~̴400 µm feature spatial resolution. The chosen architectures are defined as woodpiles (BCC, FCC and 60 deg rotating). The period is chosen to be of 1200 µm corresponding to 800 µm pores. The produced objects structural quality is characterized using scanning electron microscope, their mechanical properties such as flexural modulus, elastic modulus and stiffness are evaluated by measured experimentally using universal TIRAtest2300 machine. Within the limitation of the carried out study we show that the mechanical properties of 3D printed objects can be tuned at least 3 times by only changing the woodpile geometry arrangement, yet keeping the same filling factor and periodicity of the logs. Additionally, we demonstrate custom 3D printed µ-fluidic elements which can serve as cheap, biocompatible and environmentally biodegradable platforms for integrated Lab-On-Chip (LOC) devices.

  15. Comparison and preparation of multilayered polylactic acid fabric strengthen calcium phosphate-based bone substitutes for orthopedic applications.

    Science.gov (United States)

    Chen, Wen-Cheng; Ko, Chia-Ling; Yang, Jia-Kai; Wu, Hui-Yu; Lin, Jia-Horng

    2016-03-01

    An attempt to maintain the three-dimensional space into restorative sites through the conveniently pack porous fillers are general used strategy. Advancement in the manufacturing protective shells in the scaffolds, which would be filled with brittle ceramic grafts for the development of highly connective pores provides the approach to solve crack problem for generating the tissues. Therefore, multilayered braided and alkalized poly(lactic acid) (PLA) composites with calcium phosphate bone cement (CPC) were synthesized and compared. The PLA/CPC composites were divided into various groups according to a series of heat-treatment temperatures (100-190 °C) and periods (1-3 h) and then characterized. The effects of 24-h immersion on the strength decay resistance of the samples were compared. Results showed that the residual oil capped on the surfaces of alkalized PLA braid was removed, and the structure was unaltered. However, the reduced tensile stress of alkalized PLA braids was due to ester-group formation by hydrolysis. Mechanical test results of PLA/CPC composites showed that the strength significantly increased after heat treatment, except when the heating temperature was higher than the PLA melting point at approximately 160-170 °C. The degree of PLA after recrystallization became higher than that of unheated composites, thereby leading to reduced strength and toughness of the specimen. Braiding fibers of biodegradable PLA reinforced and toughened the structure particularly of the extra-brittle material of thin-sheet CPC after implantation.

  16. A Comparative Study on the Mechanical, Thermal and Morphological Characterization of Poly(lactic acid/Epoxidized Palm Oil Blend

    Directory of Open Access Journals (Sweden)

    Chieng Buong Woei

    2012-05-01

    Full Text Available In this work, poly(lactic acid (PLA a fully biodegradable thermoplastic polymer matrix was melt blended with three different epoxidized palm oil (EPO. The aim of this research was to enhance the flexibility, mechanical and thermal properties of PLA. The blends were prepared at various EPO contents of 1, 2, 3, 4 and 5 wt% and characterized. The SEM analysis evidenced successful modification on the neat PLA brittle morphology. Tensile tests indicate that the addition of 1 wt% EPO is sufficient to improve the strength and flexibility compared to neat PLA. Additionally, the flexural and impact properties were also enhanced. Further, DSC analysis showed that the addition of EPO results in a decrease in Tg, which implies an increase in the PLA chain mobility. In the presence of 1 wt% EPO, TGA results revealed significant increase in the thermal stability by 27%. Among the three EPOs used, EPO(3 showed the best mechanical and thermal properties compared to the other EPO’s, with an optimum loading of 1 wt%. Conclusively, EPO showed a promising outcome to overcome the brittleness and improve the overall properties of neat PLA, thus can be considered as a potential plasticizer.

  17. Chopped basalt fibres: A new perspective in reinforcing poly(lactic acid to produce injection moulded engineering composites from renewable and natural resources

    Directory of Open Access Journals (Sweden)

    P. Tamas

    2013-02-01

    Full Text Available This paper focuses on the reinforcing of Poly(lactic acid with chopped basalt fibres by using silane treated and untreated basalt fibres. Composite materials with 5–10–15–20–30–40 wt% basalt fibre contents were prepared from silane sized basalt fibres using extrusion, and injection moulding, while composites with 5–10–15 wt% basalt fibre contents were also prepared by using untreated basalt fibres as control. The properties of the injection moulded composites were extensively examined by using quasi-static (tensile, three-point bending and dynamic mechanical tests (notched and unnotched Charpy impact tests, dynamic mechanical analysis (DMA, differential scanning calorimetry (DSC, heat deflection temperature (HDT analysis, dimensional stability test, as well as melt flow index (MFI analysis and scanning electron microscopic (SEM observations. It was found that silane treated chopped basalt fibres are much more effective in reinforcing Poly(lactic acid than natural fibres; although basalt fibres are not biodegradable but they are still considered as natural (can be found in nature in the form of volcanic rocks and biologically inert. It is demonstrated in this paper that by using basalt fibre reinforcement, a renewable and natural resource based composite can be produced by injection moulding with excellent mechanical properties suitable even for engineering applications. Finally it was shown that by using adequate drying of the materials, composites with higher mechanical properties can be achieved compared to literature data.

  18. Sterilization, toxicity, biocompatibility and clinical applications of polylactic acid/polyglycolic acid copolymers.

    Science.gov (United States)

    Athanasiou, K A; Niederauer, G G; Agrawal, C M

    1996-01-01

    This is a review of salient studies of sterilization, toxicity, biocompatibility, clinical applications and current work in the field of orthopaedics, using implants made of polylactic acid (PLA), polyglycolic acid (PGA) and their copolymers. The intrinsic nature of these biomaterials renders them suitable for applications where temporally slow releases of bioactive agents in situ may be required. They are also desirable as fixation devices of bone, because they can virtually eliminate osteopenia associated with stress shielding or additional surgery. The majority of currently available sterilization techniques are not suitable for these thermoplastic materials and it may be desirable to develop new sterilization standards, which can account for the special character of PLA-PGA materials. Biocompatibility and toxicity studies suggest that, overall, PLA-PGA biomaterials may be suitable for orthopaedic applications, although certain problems, especially pertaining to reduction in cell proliferation, have been reported. Clinical applications are also promising, albeit not without problems usually associated with transient tissue inflammation. The future of these materials appears bright, especially in soft tissues. They may be used to address the exceedingly complex problem of osteochondral repair, but also as a means to enhance fixation and repair processes in tendons and ligaments. PMID:8624401

  19. Endothelial Differentiation of Human Adipose-Derived Stem Cells on Polyglycolic Acid/Polylactic Acid Mesh.

    Science.gov (United States)

    Deng, Meng; Gu, Yunpeng; Liu, Zhenjun; Qi, Yue; Ma, Gui E; Kang, Ning

    2015-01-01

    Adipose-derived stem cell (ADSC) is considered as a cell source potentially useful for angiogenesis in tissue engineering and regenerative medicine. This study investigated the growth and endothelial differentiation of human ADSCs on polyglycolic acid/polylactic acid (PGA/PLA) mesh compared to 2D plastic. Cell adhesion, viability, and distribution of hADSCs on PGA/PLA mesh were observed by CM-Dil labeling, live/dead staining, and SEM examination while endothelial differentiation was evaluated by flow cytometry, Ac-LDL/UEA-1 uptake assay, immunofluorescence stainings, and gene expression analysis of endothelial related markers. Results showed hADSCs gained a mature endothelial phenotype with a positive ratio of 21.4 ± 3.7% for CD31+/CD34- when induced in 3D mesh after 21 days, which was further verified by the expressions of a comprehensive range of endothelial related markers, whereas hADSCs in 2D induced and 2D/3D noninduced groups all failed to differentiate into endothelial cells. Moreover, compared to 2D groups, the expression for α-SMA was markedly suppressed in 3D cultured hADSCs. This study first demonstrated the endothelial differentiation of hADSCs on the PGA/PLA mesh and pointed out the synergistic effect of PGA/PLA 3D culture and growth factors on the acquisition of mature characteristic endothelial phenotype. We believed this study would be the initial step towards the generation of prevascularized tissue engineered constructs.

  20. Docetaxel-loaded polylactic acid-co-glycolic acid nanoparticles: formulation, physicochemical characterization and cytotoxicity studies.

    Science.gov (United States)

    Pradhan, Roshan; Poudel, Bijay Kumar; Ramasamy, Thiruganesh; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2013-08-01

    In the present study, we developed novel docetaxel (DTX)-loaded polylactic acid-co-glycolic acid (PLGA) nanoparticles (NPs) using the combination of sodium lauryl sulfate (SLS) and poloxamer 407, the anionic and non-ionic surfactants respectively for stabilization. The NPs were prepared by emulsification/solvent evaporation method. The combination of these surfactants at weight ratio of 1:0.5 was able to produce uniformly distributed small sized NPs and demonstrated the better stability of NP dispersion with high encapsulation efficiency (85.9 +/- 0.6%). The drug/polymer ratio and phase ratio were 2:10 and 1:10, respectively. The optimized formulation of DTX-loaded PLGA NPs had a particle size and polydispersity index of 104.2 +/- 1.5 nm and 0.152 +/- 0.006, respectively, which was further supported by TEM image. In vitro release study was carried out with dialysis membrane and showed 32% drug release in 192 h. When in vitro release data were fitted to Korsmeyer-Peppas model, the n value was 0.481, which suggested the drug was released by anomalous or non-Fickian diffusion. In addition, DTX-loaded PLGA NPs in 72 h, displayed approximately 75% cell viability reduction at 10 microg/ml DTX concentration, in MCF-7 cell lines, indicating sustained release from NPs. Therefore, our results demonstrated that incorporation of DTX into PLGA NPs could provide a novel effective nanocarrier for the treatment of cancer.

  1. Processing and Characterization of Cellulose Nanocrystals/Polylactic Acid Nanocomposite Films

    Directory of Open Access Journals (Sweden)

    Erin M. Sullivan

    2015-12-01

    Full Text Available The focus of this study is to examine the effect of cellulose nanocrystals (CNC on the properties of polylactic acid (PLA films. The films are fabricated via melt compounding and melt fiber spinning followed by compression molding. Film fracture morphology, thermal properties, crystallization behavior, thermo-mechanical behavior, and mechanical behavior were determined as a function of CNC content using scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, dynamic mechanical analysis, and tensile testing. Film crystallinity increases with increasing CNC content indicating CNC act as nucleating agents, promoting crystallization. Furthermore, the addition of CNC increased the film storage modulus and slightly broadened the glass transition region.

  2. Carbon Microparticles from Organosolv Lignin as Filler for Conducting Poly(Lactic Acid

    Directory of Open Access Journals (Sweden)

    Janea Köhnke

    2016-05-01

    Full Text Available Carbon microparticles were produced from organosolv lignin at 2000 °C under argon atmosphere following oxidative thermostabilisation at 250 °C. Scanning electron microscopy, X-ray diffraction, small-angle X-ray scattering, and electro-conductivity measurements revealed that the obtained particles were electrically conductive and were composed of large graphitic domains. Poly(lactic acid filled with various amounts of lignin-derived microparticles showed higher tensile stiffness increasing with particle load, whereas strength and extensibility decreased. Electric conductivity was measured at filler loads equal to and greater than 25% w/w.

  3. Distribution and Orientation of Carbon Fibers in Polylactic Acid Parts Produced by Fused Deposition Modeling

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; W. Gutmann, Ingomar; Koch, Thomas;

    2016-01-01

    The aim of this paper is the understanding of the fiber orientation by investigations in respect to the inner configuration of a polylactic acid matrix reinforced with short carbon fibers after a fused deposition modeling extrusion process. The final parts were analyzed by X-ray, tomography, and ...... magnetic resonance imaging allowing a resolved orientation of the fibers and distribution within the part. The research contributes to the understanding of the fiber orientation and fiber reinforcement of fused deposition modeling parts in additive manufacturing....

  4. Preparation and Photodynamic Anti-tumor Activity of Magnetic Polylactic Acid Nanoparticles Loaded with Photosensitizer

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-xia; HUANG Hui; CHEN Zhi-long; HUANG Peng; SUN Yun; ZHOU Xing-ping

    2010-01-01

    A novel magnetic nanocarrier was strategically designed and successfully prepared. Photosensitizer 2, 7,12, 18-tetramethyl-3, 8-di-(1-propoxyethyl)-13, 17-bis-( 3-hydroxypropyl ) porphyrin ( PHPP ) wasencapsulated into polylactic acid (PLA)-coated Fe3O4nanoparticles. The diameter of nanocarrier is 30-50 nm by transmission electron micrograph ( TEM ). The encapsulation efficiency of photosensitizer is 27.98% calculated from UV-vis absorption spectra. The nanocarrier shows obvious photocytotoxic activity to Hela299 tumor cells in vitro.

  5. Effect of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits

    Institute of Scientific and Technical Information of China (English)

    LIU Li-min; SONG Yue-ming; DUAN Hong; DING Yong-li; LU Bing

    2006-01-01

    Objective: To determine the efficacy of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits.Methods: Twenty-four apanese white rabbits underwent laminectomy (including the attached ligaments)at L2 and Ls. After laminectomy at L5, polylactic acid glue was sprayed on the dura and nerve roots and this segment was taken as the experimental group. After laminectomy at L2 , nothing was used and this segment was enrolled as the self control group. Four rabbits were killed every two weeks postoperatively till the end of the experiment at 12weeks. Then the operated spine was observed grossly,histologically and ultrastructurally to check the degree of scar formation, the status of epidural scar adhesion, the absorption of the glue, and the intracellular structure of fibroblasts.Results: The glue coagulated immediately after spraying and showed excellent hemostatic effect. The glue membrane was easy to be taken away from the dura mater of the samples for 2 weeks and there were no cells in the epidural space in the experimental group. But the dura mater was covered by hematoma in the control group,which formed mild adhesion, with fibroblasts proliferating actively. In the 4th week, some glue shivers remained in the epidural space with fibroblasts increasing a little, and the dura mater was smooth in the experimental group.However, in the control group, the formed scar was fragile and conglutinated with the dura mater diffusely and fibroblasts were much more than those in the experimental group. In the 6th-12th weeks, there was a potential interspace between the scar and the dura mater, and the polylactic acid glue was absorbed completely in the experimental group. Much tough scar was found in the control group, which was very difficult to dissect from the dura mater and the surrounding tissues. From the ultrastructural observation of the fibroblasts, the nucleus became much bigger and the rough endoplasmic reticulum was much more plentiful in

  6. Endothelial Differentiation of Human Adipose-Derived Stem Cells on Polyglycolic Acid/Polylactic Acid Mesh

    Directory of Open Access Journals (Sweden)

    Meng Deng

    2015-01-01

    Full Text Available Adipose-derived stem cell (ADSC is considered as a cell source potentially useful for angiogenesis in tissue engineering and regenerative medicine. This study investigated the growth and endothelial differentiation of human ADSCs on polyglycolic acid/polylactic acid (PGA/PLA mesh compared to 2D plastic. Cell adhesion, viability, and distribution of hADSCs on PGA/PLA mesh were observed by CM-Dil labeling, live/dead staining, and SEM examination while endothelial differentiation was evaluated by flow cytometry, Ac-LDL/UEA-1 uptake assay, immunofluorescence stainings, and gene expression analysis of endothelial related markers. Results showed hADSCs gained a mature endothelial phenotype with a positive ratio of 21.4 ± 3.7% for CD31+/CD34− when induced in 3D mesh after 21 days, which was further verified by the expressions of a comprehensive range of endothelial related markers, whereas hADSCs in 2D induced and 2D/3D noninduced groups all failed to differentiate into endothelial cells. Moreover, compared to 2D groups, the expression for α-SMA was markedly suppressed in 3D cultured hADSCs. This study first demonstrated the endothelial differentiation of hADSCs on the PGA/PLA mesh and pointed out the synergistic effect of PGA/PLA 3D culture and growth factors on the acquisition of mature characteristic endothelial phenotype. We believed this study would be the initial step towards the generation of prevascularized tissue engineered constructs.

  7. Biodegradation of sulfanilic acid by Pseudomonas paucimobilis.

    Science.gov (United States)

    Perei, K; Rákhely, G; Kiss, I; Polyák, B; Kovács, K L

    2001-01-01

    An aerobic bacterium, isolated from a contaminated site, was able to degrade sulfanilic acid (4-aminobenzenesulfonic acid) and was identified as Pseudomonas paucimobilis. The isolate could grow on sulfanilic acid (SA) as its sole carbon and nitrogen source and metabolized the target compound to biomass. The bioconversion capacity depended on the sulfanilic acid concentration; greater than 98% elimination of the hazardous compound was achieved at low (10 mM) sulfanilic acid concentration, and the yield was greater than 70% at 50 mM concentration of the contaminant. The maximum conversion rate was 1.5 mmol sulfanilic acid/h per mg wet cells at 30 degrees C. Ca-alginate-phytagel proved a good matrix for immobilization of P. paucimobilis, with essentially unaltered biodegradation activity. Removal of sulfanilic acid from contaminated industrial waste water was demonstrated. SDS-PAGE analysis of the crude extract revealed novel proteins appearing upon induction with sulfanilic acid and related compounds, which indicated alternative degradation mechanisms involving various inducible enzymes.

  8. Surface Functional Poly(lactic Acid Electrospun Nanofibers for Biosensor Applications

    Directory of Open Access Journals (Sweden)

    Edurne González

    2016-01-01

    Full Text Available In this work, biotin surface functionalized hydrophilic non-water-soluble biocompatible poly(lactic acid (PLA nanofibers are created for their potential use as biosensors. Varying concentrations of biotin (up to 18 weight total percent (wt % were incorporated into PLA fibers together with poly(lactic acid-block-poly(ethylene glycol (PLA-b-PEG block polymers. While biotin provided surface functionalization, PLA-b-PEG provided hydrophilicity to the final fibers. Morphology and surface-available biotin of the final fibers were studied by Field Emission Scanning Electron Microscopy (FESEM and competitive colorimetric assays. The incorporation of PLA-b-PEG block copolymers not only decreased fiber diameters but also dramatically increased the amount of biotin available at the fiber surface able to bind avidin. Finally, fiber water stability tests revealed that both biotin and PLA-b-PEG, migrated to the aqueous phase after relatively extended periods of water exposure. The functional hydrophilic nanofiber created in this work shows a potential application as a biosensor for point-of-care diagnostics.

  9. MWCNTs-reinforced epoxidized linseed oil plasticized polylactic acid nanocomposite and its electroactive shape memory behaviour.

    Science.gov (United States)

    Alam, Javed; Alam, Manawwer; Raja, Mohan; Abduljaleel, Zainularifeen; Dass, Lawrence Arockiasamy

    2014-01-01

    A novel electroactive shape memory polymer nanocomposite of epoxidized linseed oil plasticized polylactic acid and multi-walled carbon nanotubes (MWCNTs) was prepared by a combination of solution blending, solvent cast technique, and hydraulic hot press moulding. In this study, polylactic acid (PLA) was first plasticized by epoxidized linseed oil (ELO) in order to overcome the major limitations of PLA, such as high brittleness, low toughness, and low tensile elongation. Then, MWCNTs were incorporated into the ELO plasticized PLA matrix at three different loadings (2, 3 and 5 wt. %), with the aim of making the resulting nanocomposites electrically conductive. The addition of ELO decreased glass transition temperature, and increased the elongation and thermal degradability of PLA, as shown in the results of differential scanning calorimetry (DSC), tensile test, and thermo gravimetric analysis (TGA). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe surface morphology, topography, and the dispersion of MWCNTs in the nanocomposite. Finally, the electroactive-shape memory effect (electroactive-SME) in the resulting nanocomposite was investigated by a fold-deploy "U"-shape bending test. As per the results, the addition of both ELO and MWCNTs to PLA matrix seemed to enhance its overall properties with a great deal of potential in improved shape memory. The 3 wt. % MWCNTs-reinforced nanocomposite system, which showed 95% shape recovery within 45 s at 40 DC voltage, is expected to be used as a preferential polymeric nanocomposite material in various actuators, sensors and deployable devices. PMID:25365179

  10. MWCNTs-Reinforced Epoxidized Linseed Oil Plasticized Polylactic Acid Nanocomposite and Its Electroactive Shape Memory Behaviour

    Directory of Open Access Journals (Sweden)

    Javed Alam

    2014-10-01

    Full Text Available A novel electroactive shape memory polymer nanocomposite of epoxidized linseed oil plasticized polylactic acid and multi-walled carbon nanotubes (MWCNTs was prepared by a combination of solution blending, solvent cast technique, and hydraulic hot press moulding. In this study, polylactic acid (PLA was first plasticized by epoxidized linseed oil (ELO in order to overcome the major limitations of PLA, such as high brittleness, low toughness, and low tensile elongation. Then, MWCNTs were incorporated into the ELO plasticized PLA matrix at three different loadings (2, 3 and 5 wt. %, with the aim of making the resulting nanocomposites electrically conductive. The addition of ELO decreased glass transition temperature, and increased the elongation and thermal degradability of PLA, as shown in the results of differential scanning calorimetry (DSC, tensile test, and thermo gravimetric analysis (TGA. Scanning electron microscopy (SEM and atomic force microscopy (AFM were used to observe surface morphology, topography, and the dispersion of MWCNTs in the nanocomposite. Finally, the electroactive-shape memory effect (electroactive-SME in the resulting nanocomposite was investigated by a fold-deploy “U”-shape bending test. As per the results, the addition of both ELO and MWCNTs to PLA matrix seemed to enhance its overall properties with a great deal of potential in improved shape memory. The 3 wt. % MWCNTs-reinforced nanocomposite system, which showed 95% shape recovery within 45 s at 40 DC voltage, is expected to be used as a preferential polymeric nanocomposite material in various actuators, sensors and deployable devices.

  11. Poly(lactic acid/Carbon Nanotube Fibers as Novel Platforms for Glucose Biosensors

    Directory of Open Access Journals (Sweden)

    Valtencir Zucolotto

    2012-02-01

    Full Text Available The focus of this paper is the development and investigation of properties of new nanostructured architecture for biosensors applications. Highly porous nanocomposite fibers were developed for use as active materials in biosensors. The nanocomposites comprised poly(lactic acid(PLA/multi-walled carbon nanotube (MWCNT fibers obtained via solution-blow spinning onto indium tin oxide (ITO electrodes. The electrocatalytic properties of nanocomposite-modified ITO electrodes were investigated toward hydrogen peroxide (H2O2 detection. We investigated the effect of carbon nanotube concentration and the time deposition of fibers on the sensors properties, viz., sensitivity and limit of detection. Cyclic voltammetry experiments revealed that the nanocomposite-modified electrodes displayed enhanced activity in the electrochemical reduction of H2O2, which offers a number of attractive features to be explored in development of an amperometric biosensor. Glucose oxidase (GOD was further immobilized by drop coating on an optimized ITO electrode covered by poly(lactic acid/carbon nanotube nanofibrous mats. The optimum biosensor response was linear up to 800 mM of glucose with a sensitivity of 358 nA·mM−1 and a Michaelis-Menten constant (KM of 4.3 mM. These results demonstrate that the solution blow spun nanocomposite fibers have great potential for application as amperometric biosensors due to their high surface to volume ratio, high porosity and permeability of the substrate. The latter features may significantly enhance the field of glucose biosensors.

  12. Water vapour permeability of poly(lactic acid): Crystallinity and the tortuous path model

    Science.gov (United States)

    Duan, Z.; Thomas, N. L.

    2014-02-01

    The water vapour transmission rates (WVTR) through samples of polylactic acid of different crystallinities have been measured. Three different grades of commercial poly(lactic acid) (PLA) were used with different ratios of L-lactide and D-lactide to give a range of crystallinities from 0% to 50%. Sheets of PLA were prepared by melt compounding followed by compression moulding and annealing at different temperatures and for different times to give the range of crystallinities required. Crystallinity was measured by differential scanning calorimetry and the morphology of the samples was observed under crossed polars in a transmitted light microscope. Water vapour transmission rates through the films were measured at 38 °C and at a relative humidity of 90%. It was found that the measured values of WVTR decreased linearly with increasing crystallinity of the PLA from 0% to 50%. The results are discussed in terms of the effect of crystallinity on solubility and shown to fit the "Tortuous Path Model." The model was also successfully used to explain published data on water permeability of polyethylene terephthalate.

  13. Preoperative computed tomography-guided percutaneous localization of ground glass pulmonary opacity with polylactic acid injection.

    Science.gov (United States)

    Hu, Mu; Zhi, Xiuyi; Zhang, Jian

    2015-07-01

    Localization of a ground glass nodule is a difficult challenge for thoracic surgeons, especially for ground glass opacities (GGOs) less than 10 mm in diameter. In this study we implement a new method for preoperative localization of pulmonary (GGOs). From October 2013 to December 2014, computed tomography-guided percutaneous polylactic acid injection localizations were performed for five pulmonary nodules in five patients (2 men and 3 women; mean age, 59.8 years; range, 54-65 years). The injection was feasible in all patients and the localization effect was excellent. The total procedure duration was 12.6 minutes (range; 10-15) and the volume of polylactic acid injected was 0.38 mL. The wedge resections were easily and successfully performed in all five cases. The cutting margin was no less than 2 cm from the lesion. This technique is promising for the determination of GGO location in thoracoscopic surgery for wedge resection.

  14. Polylactic-co-glycolic acid microspheres containing three neurotrophic factors promote sciatic nerve repair after injury

    Institute of Scientific and Technical Information of China (English)

    Qun Zhao; Zhi-yue Li; Ze-peng Zhang; Zhou-yun Mo; Shi-jie Chen; Si-yu Xiang; Qing-shan Zhang; Min Xue

    2015-01-01

    A variety of neurotrophic factors have been shown to repair the damaged peripheral nerve. However, in clinical practice, nerve growth factor, neurotrophin-3 and brain-derived neuro-trophic factor are all peptides or proteins that may be rapidly deactivated at the focal injury site;their local effective concentration time following a single medication cannot meet the required time for spinal axons to regenerate and cross the glial scar. In this study, we produced polymer sustained-release microspheres based on the polylactic-co-glycolic acid copolymer; the micro-spheres at 300-µm diameter contained nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor. Six microspheres were longitudinally implanted into the sciatic nerve at the anastomosis site, serving as the experimental group; while the sciatic nerve in the control group was subjected to the end-to-end anastomosis using 10/0 suture thread. At 6 weeks after implanta-tion, the lower limb activity, weight of triceps surae muscle, sciatic nerve conduction velocity and the maximum amplitude were obviously better in the experimental group than in the control group. Compared with the control group, more regenerating nerve ifbers were observed and dis-tributed in a dense and ordered manner with thicker myelin sheaths in the experimental group. More angiogenesis was also visible. Experimental findings indicate that polylactic-co-glycolic acid composite microspheres containing nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor can promote the restoration of sciatic nerve in rats after injury.

  15. MWCNTs-reinforced epoxidized linseed oil plasticized polylactic acid nanocomposite and its electroactive shape memory behaviour.

    Science.gov (United States)

    Alam, Javed; Alam, Manawwer; Raja, Mohan; Abduljaleel, Zainularifeen; Dass, Lawrence Arockiasamy

    2014-10-31

    A novel electroactive shape memory polymer nanocomposite of epoxidized linseed oil plasticized polylactic acid and multi-walled carbon nanotubes (MWCNTs) was prepared by a combination of solution blending, solvent cast technique, and hydraulic hot press moulding. In this study, polylactic acid (PLA) was first plasticized by epoxidized linseed oil (ELO) in order to overcome the major limitations of PLA, such as high brittleness, low toughness, and low tensile elongation. Then, MWCNTs were incorporated into the ELO plasticized PLA matrix at three different loadings (2, 3 and 5 wt. %), with the aim of making the resulting nanocomposites electrically conductive. The addition of ELO decreased glass transition temperature, and increased the elongation and thermal degradability of PLA, as shown in the results of differential scanning calorimetry (DSC), tensile test, and thermo gravimetric analysis (TGA). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe surface morphology, topography, and the dispersion of MWCNTs in the nanocomposite. Finally, the electroactive-shape memory effect (electroactive-SME) in the resulting nanocomposite was investigated by a fold-deploy "U"-shape bending test. As per the results, the addition of both ELO and MWCNTs to PLA matrix seemed to enhance its overall properties with a great deal of potential in improved shape memory. The 3 wt. % MWCNTs-reinforced nanocomposite system, which showed 95% shape recovery within 45 s at 40 DC voltage, is expected to be used as a preferential polymeric nanocomposite material in various actuators, sensors and deployable devices.

  16. Polylactic-co-glycolic acid microspheres containing three neurotrophic factors promote sciatic nerve repair after injury.

    Science.gov (United States)

    Zhao, Qun; Li, Zhi-Yue; Zhang, Ze-Peng; Mo, Zhou-Yun; Chen, Shi-Jie; Xiang, Si-Yu; Zhang, Qing-Shan; Xue, Min

    2015-09-01

    A variety of neurotrophic factors have been shown to repair the damaged peripheral nerve. However, in clinical practice, nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor are all peptides or proteins that may be rapidly deactivated at the focal injury site; their local effective concentration time following a single medication cannot meet the required time for spinal axons to regenerate and cross the glial scar. In this study, we produced polymer sustained-release microspheres based on the polylactic-co-glycolic acid copolymer; the microspheres at 300-μm diameter contained nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor. Six microspheres were longitudinally implanted into the sciatic nerve at the anastomosis site, serving as the experimental group; while the sciatic nerve in the control group was subjected to the end-to-end anastomosis using 10/0 suture thread. At 6 weeks after implantation, the lower limb activity, weight of triceps surae muscle, sciatic nerve conduction velocity and the maximum amplitude were obviously better in the experimental group than in the control group. Compared with the control group, more regenerating nerve fibers were observed and distributed in a dense and ordered manner with thicker myelin sheaths in the experimental group. More angiogenesis was also visible. Experimental findings indicate that polylactic-co-glycolic acid composite microspheres containing nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor can promote the restoration of sciatic nerve in rats after injury.

  17. Biodegradation of clofibric acid and identification of its metabolites

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, R. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); ESTS-IPS, Escola Superior de Tecnologia de Setubal do Instituto Politecnico de Setubal, Rua Vale de Chaves, Campus do IPS, Estefanilha, 2910-761 Setubal (Portugal); Oehmen, A. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Carvalho, G. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Instituto de Biologia Experimental e Tecnologica (IBET), Av. da Republica (EAN), 2784-505 Oeiras (Portugal); Noronha, J.P. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Reis, M.A.M., E-mail: amr@fct.unl.pt [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2012-11-30

    Graphical abstract: Metabolites produced during clofibric acid biodegradation. Highlights: Black-Right-Pointing-Pointer Clofibric acid is biodegradable. Black-Right-Pointing-Pointer Mainly heterotrophic bacteria degraded the clofibric acid. Black-Right-Pointing-Pointer Metabolites of clofibric acid biodegradation were identified. Black-Right-Pointing-Pointer The metabolic pathway of clofibric acid biodegradation is proposed. - Abstract: Clofibric acid (CLF) is the pharmaceutically active metabolite of lipid regulators clofibrate, etofibrate and etofyllinclofibrate, and it is considered both environmentally persistent and refractory. This work studied the biotransformation of CLF in aerobic sequencing batch reactors (SBRs) with mixed microbial cultures, monitoring the efficiency of biotransformation of CLF and the production of metabolites. The maximum removal achieved was 51% biodegradation (initial CLF concentration = 2 mg L{sup -1}), where adsorption and abiotic removal mechanisms were shown to be negligible, showing that CLF is indeed biodegradable. Tests showed that the observed CLF biodegradation was mainly carried out by heterotrophic bacteria. Three main metabolites were identified, including {alpha}-hydroxyisobutyric acid, lactic acid and 4-chlorophenol. The latter is known to exhibit higher toxicity than the parent compound, but it did not accumulate in the SBRs. {alpha}-Hydroxyisobutyric acid and lactic acid accumulated for a period, where nitrite accumulation may have been responsible for inhibiting their degradation. A metabolic pathway for the biodegradation of CLF is proposed in this study.

  18. Melting of α'- and α-crystals of poly(lactic acid)

    Science.gov (United States)

    Di Lorenzo, Maria Laura; Androsch, René

    2016-05-01

    The influence of chain structure on thermal stability of α'-crystals of poly(lactic acid) (PLA) with high L-lactic acid content (96-100 %) is detailed in this contribution. α'-crystals of PLA grow at temperatures below 120 °C, and spontaneously transform into stable α-modification during heating. Using conventional differential scanning calorimetry (DSC) and fast scanning chip calorimetry (FSC), a wide range of scanning rates, between about 10-1 and 102 K s-1 could be tested. It was found that reorganization of disordered α'-crystals into stable α-crystals can be suppressed by fast heating. The critical heating rate needed to completely melt α'-crystals and to avoid formation of α-crystals on continuation of heating varies with the chain composition, and decreases upon increase of the D-lactic acid content in the PLA chain.

  19. Antibacterial poly(lactic acid) (PLA) films grafting electrospun PLA/Ally isothioscyanate (AITC) fibers for food packaging

    Science.gov (United States)

    Poly(lactic acid) (PLA) fibers of submicron sizes encapsulating allyl isothiocyanate (AITC) (PfA) were made and electrospun onto the surfaces of PLA films (PfA-g-film). SEM examination confirmed that the fibers were grafted to the PLA film after the (PfA-g-film) underwent air blowing and water washi...

  20. Chemical and Sensory Evaluation of Silicone and Polylactic Acid-Based Remedial Treatments for Elevated Methoxypyrazine Levels in Wine.

    Science.gov (United States)

    Botezatu, Andreea; Kemp, Belinda S; Pickering, Gary J

    2016-09-16

    Alkylmethoxypyrazines (MPs) are a class of compounds that can elicit undesirable aroma and flavor characteristics in wine, and resist remediation using traditional wine making approaches. MPs are grape-derived constituents as well as contaminants from Coccinellidae beetles present during wine processing; the latter eliciting an off-flavor referred to as 'ladybug taint'. In this study we investigated the capacity of two plastic polymers-one silicone-based, the other polylactic acid-based-applied with varying surface areas to reduce concentrations of isopropylmethoxypyrazine (IPMP), sec-butylmethoxypyrazine (SBMP) and isobutylmethoxypyrazine (IBMP) in a Merlot wine using multi-dimensional gas chromatography coupled with mass spectrometry and headspace solid phase microextraction (SPME-MDGCMS). The impact of treatments on the sensory characteristics of the wine (descriptive analysis) and volatile aroma compounds (VOCs) (SPME-MDGCMS) was also investigated. Results showed substantial reductions for all of the target odorants: up to 38%, 44% and 39% for IPMP, SBMP and IBMP, respectively, for the silicone polymer, and up to 75%, 78% and 77% for IPMP, SBMP and IBMP, respectively, for the polylactic acid polymer. These polymers had no or minimal effect on VOCs at applications of 200 cm²/L for silicone or for all polylactic acid treatments. Sensory impacts were less clear, but generally showed minimal effect from the treatments. Taken overall, the data confirm the utility of both polylactic acid and silicone polymers in reducing elevated levels of grape-derived MPs, as well as potentially improving wine contaminated by ladybug taint.

  1. Functionalized graphene with polymer toughener as novel interface modifier for property-tailored poly(lactic acid)/graphene nanocomposites

    Science.gov (United States)

    In this work, an effective strategy for engineering the interfacial compatibility between graphene and polylactic acid (PLA) was developed by manipulating the functionalization of graphene and introducing an epoxy-containing elastomer modifier. Curing between the functional groups of the modified gr...

  2. Production and characterization of 166Ho polylactic acid microspheres.

    Science.gov (United States)

    Yavari, Kamal; Yeganeh, Ehsan; Abolghasemi, Hossein

    2016-01-01

    Microsphere and particle technology with selective transport of radiation represents a new generation of therapeutics. Poly-L-lactic acid (PLLA) microspheres loaded with holmium-166 acetylacetonate ((166)Ho-PLLA-MS) are novel microdevices. In this research, (165)HoAcAc-PLLA microparticles were prepared by the solvent evaporation technique. Microspheres were irradiated at Tehran Research Reactor. The diameter and surface morphologies were characterized by particle sizer and scanning electron microscopy before and after irradiation. The complex stability, radiochemical purity, and in vivo biodistribiotion were checked in the final solution up to 3 days. In this study, (166)Ho-PLLA spherical particles with a smooth surface and diameter of 20-40 µm were obtained, which were stable in vitro and in vivo studies. Neutron irradiation did not damage the particles. The ease with which the PLLA spheres could be made in the optimal size range for later irradiation and their ability to retain the (166)Ho provided good evidence for their potential use in radioembolization.

  3. Characterisation of solution cast cellulose nanofibre – reinforced poly(lactic acid

    Directory of Open Access Journals (Sweden)

    2010-01-01

    Full Text Available Cellulose nanofibres, 20 nm in diameter and 300 nm long, were prepared by acid hydrolysis of flax yarns. Composite films containing 2.5 and 5.0 wt% flax cellulose (FC fibres were prepared by solution casting of mixtures of poly(lactic acid (PLA solution and cellulose nanofibre suspension in chloroform. The resulting composite films and solution cast pure PLA film, with thickness of around 160 m, showed good transparency. For composites with 2.5 and 5.0 wt% FC, the tensile strength increased by 25 and 59% and tensile modulus by 42 and 47%, respectively, compared to pure PLA film. The composite film with 2.5 wt% FC combined high strength and ductility with tensile strength of 24.3 MPa and 70% elongation at break. Flax cellulose appeared to facilitate nucleation and subsequent crystallisation of PLA more effectively in the amorphous composites than in the crystalline composites.

  4. Morphologies, mechanical properties and thermal stability of poly(lactic acid) toughened by precipitated barium sulfate

    Science.gov (United States)

    Yang, Jinian; Wang, Chuang; Shao, Kaiyun; Ding, Guoxin; Tao, Yulun; Zhu, Jinbo

    2015-11-01

    Poly(lactic acid) (PLA)-based composites were prepared by blending PLA with precipitated barium sulfate (BaSO4) modified with stearic acid. The morphologies, mechanical properties and thermal stability of samples with increased mass fraction of BaSO4 were investigated. Results showed that PLA was toughened and reinforced simultaneously by incorporation of precipitated BaSO4 particles. The highest impact toughness and elongation at break were both achieved at 15% BaSO4, while the elastic modulus increased monotonically with increasing BaSO4 loading. Little effect of BaSO4 on the thermal behavior of PLA was observed in the present case. However, the thermal stability of PLA/BaSO4 composites at high temperature was enhanced.

  5. Preparation and characterization of aligned carbon nanotubes/polylactic acid composite fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kong Yuxia; Yuan Jie [School of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Qiu Jun, E-mail: qiujun@tongji.edu.cn [School of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Key Laboratory of Advanced Civil Engineering Materials of Education of Ministry, Shanghai 201804 (China)

    2012-07-01

    Aligned functionalized multiwalled carbon nanotubes/polylactic acid (MWNTs-PCL/PLA) composite fibers were successfully prepared by electrospinning processing. The MWNTs bonded with the polycaprolactone chains exhibited excellent uniform dispersion in PLA solution by comparing with the acid-functionalized MWNTs and amino-functionalized MWNTs. Optical microscopy was used to study the aligned degree of the fibers and to investigate the influences of the electrodes distance on the alignment and structure of the fibers, and results showed that the best quality of aligned fibers with dense structure and high aligned degree were obtained at an electrodes distance of 3 cm. Moreover, the MWNTs embedded inside the MWNTs-PCL/PLA fibers displayed well orientation along the axes of the fibers, which was demonstrated by field emission scanning electron microscopy, transmission electron microscopy and Raman spectroscopy.

  6. 聚乳酸纤维抗菌织物%The Development of Polylactic Acid Fiber Antibacterial Fabric

    Institute of Scientific and Technical Information of China (English)

    赵金龙; 沈兰萍; 徐玲

    2013-01-01

    选用14.6 tex的聚乳酸纱线作为原料,用ASS3000单纱机对纱线进行上浆,SV111型剑杆自动织样机织造聚乳酸纤维平纹织物,采用Na2CO3碱液退浆法对织物进行退浆,H2O2对织物进行漂白,经热定形处理后,使用SCJ-939固着剂和CYK-302无机载银抗菌剂对织物进行抗菌整理,开发出聚乳酸纤维抗菌织物.对抗菌整理前后的聚乳酸织物的服用性能和抗菌性能进行了测试分析,研究证明:开发的聚乳酸纤维抗菌织物具有良好的服用性能和抗菌性能.%The polylactic acid yarns of 14.6 tex were used as raw materials.ASS3000 single yarn machine was used to sizing the yarn.Polylactic acid fiber plain cloth was weaved on the SV111 type rapier loom.The fabrics desized by the method of alkali desizing and H2O2 bleaching was carried out on the fabric.After heat setting treatment,the fabrics were dealed with SCJ-939 fixation agent and CYK-939 airborne silver antibacterial agent to develope the polylactic acid fiber antibacterial fabric.The wearability performance and antibacterial properties of polylactic acid fabrics were analysed to prove that the polylactic acid fiber antibacterial fabrics have good wearability and antibacterial properties.

  7. Effects of Graphene Nanoplatelets and Reduced Graphene Oxide on Poly(lactic acid and Plasticized Poly(lactic acid: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Buong Woei Chieng

    2014-08-01

    Full Text Available The superlative mechanical properties of graphene-based materials make them the ideal filler materials for polymer composites reinforcement. Two types of graphene-based materials, graphene nanoplatelets (xGnP and reduced graphene oxide (rGO, were used as nanofiller in poly(lactic acid (PLA polymer matrix, as well as plasticized PLA. The addition of rGO into PLA or plasticized PLA substantially enhanced the tensile strength without deteriorating elasticity, compared to xGnP nanocomposites. In addition, the investigation of the thermal properties has found that the presence of rGO in the system is very beneficial for improving thermal stability of the PLA or plasticized PLA. Scanning electron microscope (SEM images of the rGO nanocomposites display homogenous and good uniformity morphology. Transmission electron microscopy (TEM images revealed that the rGO remained intact as graphene sheet layers and were dispersed well into the polymer matrix, and it was confirmed by X-ray diffraction (XRD results, which shows no graphitic peak in the XRD pattern.

  8. Modeling of hyaluronic acid containing anti-cancer drugs-loaded polylactic-co-glycolic acid bioconjugates for targeted delivery to cancer cells

    Science.gov (United States)

    Gul-e-Saba, Adulphakdee, A.; Madthing, A.; Zafar, M. N.; Abdullah, M. A.

    2012-09-01

    Molecular modeling of hyaluronan (HA), polylactic-co-glycolic acid (PLGA), polyethylene glycol-bis-amine (PEG-bis-amine), Curcumin, Cisplatin and the conjugate HA-PEG-PLGA containing Curcumin/Cisplatin were performed using Discovery Studio 2.5 to better understand issues and constraints related to targeted delivery of potent anticancer drugs to cancer cells. HA, a versatile biopolymer is a ligand of cancer cell receptor, CD44 that can be particularly useful in a receptor-mediated cellular uptake of drug-incorporated nanoparticles. Biocompatible and biodegradable polymers, PLGA and PEG, serve as polymeric micelles for controlled-release of drug. Curcumin as a natural anticancer agent has poor solubility that limits its use in drug therapeutics, while platinum-based Cisplatin exhibits systemic cytotoxicity. These can be overcome via drug delivery in polymeric biocompatible vehicles. The PLGA-PEG-HA conjugate shows the total measurement of 105 bond length with average bond length of 1.274163 Å. The conjugation between PEG and HA occurs at C8-O1 atoms and can be manipulated to improve properties.

  9. Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding

    International Nuclear Information System (INIS)

    Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications. - Highlights: • Microcellular injection molding was used to fabricate tissue engineering scaffolds. • TPU/PLA tissue engineering scaffolds with tunable properties were fabricated. • Multiple test methods were used to characterize the scaffolds. • The biocompatibility of the scaffolds was confirmed by fibroblast cell culture. • Scaffolds produced have the potential to be used in multiple tissue applications

  10. Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding

    Energy Technology Data Exchange (ETDEWEB)

    Mi, Hao-Yang [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou (China); Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States); Salick, Max R. [Department of Engineering Physics, University of Wisconsin–Madison, WI (United States); Jing, Xin [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou (China); Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States); Jacques, Brianna R. [Department of Biology, University of Wisconsin–River Falls, WI (United States); Crone, Wendy C. [Department of Engineering Physics, University of Wisconsin–Madison, WI (United States); Peng, Xiang-Fang, E-mail: pmxfpeng@scut.edu.cn [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou (China); Turng, Lih-Sheng, E-mail: turng@engr.wisc.edu [Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States)

    2013-12-01

    Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications. - Highlights: • Microcellular injection molding was used to fabricate tissue engineering scaffolds. • TPU/PLA tissue engineering scaffolds with tunable properties were fabricated. • Multiple test methods were used to characterize the scaffolds. • The biocompatibility of the scaffolds was confirmed by fibroblast cell culture. • Scaffolds produced have the potential to be used in multiple tissue applications.

  11. Effects of dry method esterification of starch on the degradation characteristics of starch/polylactic acid composites.

    Science.gov (United States)

    Zuo, Ying Feng; Gu, Jiyou; Qiao, Zhibang; Tan, Haiyan; Cao, Jun; Zhang, Yanhua

    2015-01-01

    Maleic anhydride esterified corn starch was prepared by dry method. Esterified starch/polylactic acid (PLA) biodegradable composite was produced via melt extrusion method with blending maleic anhydride esterified corn starch and PLA. The influence of the dry method esterification of starch on the degradation characteristics of starch/PLA composites was investigated by the natural aging degradation which was soil burial method. Test results of mass loss rate showed that the first 30 days of degradation was mainly starch degradation, and the degradation rate of esterified starch/PLA (ES/PLA) was slower than that of native starch/PLA (NS/PLA). Therefore, the damage degree of ES/PLA on the surface and inside was smaller than that of NS/PLA, and the infrared absorption peak intensities of C-O, C=O and C-H were stronger than that of NS/PLA. With the increasing time of soil burial degradation, the damage degree of NS/PLA and ES/PLA on the exterior and interior were gradually increased, whereas the infrared absorption peak intensities of C-O, C=O and C-H were gradually decreased. The XRD diffraction peak intensity of PLA in composites showed an increased trend at first which was then followed by a decreased one along with the increasing time of soil burial degradation, indicating that the degradation of amorphous regions of PLA was earlier than its crystalline regions. When the soil burial time was the same, the diffraction peak intensity of PLA in ES/PLA was stronger than that of NS/PLA. If the degradation time was the same, T0, Ti and residual rate of thermal decomposition of NS/PLA were larger than those of ES/PLA. The tensile strength and bending strength of composites were decreased gradually with soil burial time increasing. Both the tensile strength and bending strength of ES/PLA were stronger than those of NS/PLA.

  12. Bio-safe processing of polylactic-co-caprolactone and polylactic acid blends to fabricate fibrous porous scaffolds for in vitro mesenchymal stem cells adhesion and proliferation.

    Science.gov (United States)

    Salerno, Aurelio; Guarino, Vincenzo; Oliviero, Olimpia; Ambrosio, Luigi; Domingo, Concepción

    2016-06-01

    In this study, the design and fabrication of porous scaffolds, made of blends of polylactic-co-caprolactone (PLC) and polylactic acid (PLA) polymers, for tissue engineering applications is reported. The scaffolds are prepared by means of a bio-safe thermally induced phase separation (TIPS) approach with or without the addition of NaCl particles used as particulate porogen. The scaffolds are characterized to assess their crystalline structure, morphology and mechanical properties, and the texture of the pores and the pore size distribution. Moreover, in vitro human mesenchymal stem cells (hMSCs) culture tests have been carried out to demonstrate the biocompatibility of the scaffolds. The results of this study demonstrate that all of the scaffold materials processed by means of TIPS process are semi-crystalline. Furthermore, the blend composition affected polymer crystallization and, in turn, the nano and macro-structural properties of the scaffolds. Indeed, neat PLC and neat PLA crystallize into globular and randomly arranged sub micro-size scale fibrous conformations, respectively. Concomitantly, the addition of NaCl particles during the fabrication route allows for the creation of an interconnected network of large pores inside the primary structure while resulted in a significant decrease of scaffolds mechanical response. Finally, the results of cell culture tests demonstrate that both the micro and macro-structure of the scaffold affect the in vitro hMSCs adhesion and proliferation. PMID:27040246

  13. Bio-safe processing of polylactic-co-caprolactone and polylactic acid blends to fabricate fibrous porous scaffolds for in vitro mesenchymal stem cells adhesion and proliferation.

    Science.gov (United States)

    Salerno, Aurelio; Guarino, Vincenzo; Oliviero, Olimpia; Ambrosio, Luigi; Domingo, Concepción

    2016-06-01

    In this study, the design and fabrication of porous scaffolds, made of blends of polylactic-co-caprolactone (PLC) and polylactic acid (PLA) polymers, for tissue engineering applications is reported. The scaffolds are prepared by means of a bio-safe thermally induced phase separation (TIPS) approach with or without the addition of NaCl particles used as particulate porogen. The scaffolds are characterized to assess their crystalline structure, morphology and mechanical properties, and the texture of the pores and the pore size distribution. Moreover, in vitro human mesenchymal stem cells (hMSCs) culture tests have been carried out to demonstrate the biocompatibility of the scaffolds. The results of this study demonstrate that all of the scaffold materials processed by means of TIPS process are semi-crystalline. Furthermore, the blend composition affected polymer crystallization and, in turn, the nano and macro-structural properties of the scaffolds. Indeed, neat PLC and neat PLA crystallize into globular and randomly arranged sub micro-size scale fibrous conformations, respectively. Concomitantly, the addition of NaCl particles during the fabrication route allows for the creation of an interconnected network of large pores inside the primary structure while resulted in a significant decrease of scaffolds mechanical response. Finally, the results of cell culture tests demonstrate that both the micro and macro-structure of the scaffold affect the in vitro hMSCs adhesion and proliferation.

  14. Purified terephthalic acid wastewater biodegradation and toxicity

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xu-xiang; LUO Xiang; GU Ji-dong; WAN Yu-qiu; CHENG Shu-pei; SUN Shi-lei; ZHU Cheng-jun; LI Wei-xin; ZHANG Xiao-chun; WANG Gui-lin; LU Jian-hua

    2005-01-01

    The biodegradation and toxicity of the purified terephthalic acid(PTA) processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process(CASP). Sludge loading rate(SLR) for Fhhh to COD of the wastewater was 1.09 d-1 and to PTA in the wastewater was 0.29 d-1. The results of bioassay at the pilot and calculation with software Ebis3 showed that the 48h-LC50 (median lethal concentration) to Daphnia magna for the PTA concentration in the wastewater was only 1/10 of that for the chemical PTA. There were 5 kinds of benzoate pollutants and their toxicities existing in the wastewater at least. The toxicity parameter value of the pure chemical PTA cannot be used to predicate the PTA wastewater toxicity. The toxicity of the NJYZ PTA wastewater will be discussed in detail in this paper.

  15. A novel nanofiber Cur-loaded polylactic acid constructed by electrospinning

    Science.gov (United States)

    Thu Trang Mai, Thi; Thu Thuy Nguyen, Thi; Duong Le, Quang; Ngoan Nguyen, Thi; Cham Ba, Thi; Binh Nguyen, Hai; Bich Hoa Phan, Thi; Tran, Dai Lam; Phuc Nguyen, Xuan; Park, Jun Seo

    2012-06-01

    Curcumin (Cur), extracted from the Curcuma longa L. plant, is well known for its anti-tumor, anti-oxidant, anti-inflammatory and anti-bacterial properties. Nanofiber mats of polylactic acid (PLA) loading Cur (5 wt%) were fabricated by electrospinning (e-spinning). Morphology and structure of the fibers were characterized by field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The diameters of the obtained fibers varied from 200 to 300 nm. The release capacity of curcumin from curcumin-loaded PLA fibers was investigated in phosphate buffer saline (PBS) containing ethanol. After 24 h, 50% of the curcumin was released from curcumin-loaded PLA fibers. These results of electrospun (e-spun) fibers exhibit the potential for biomedical application.

  16. Poly(lactic acid) microencapsulated oxytetracycline: in vitro and in vivo evaluation.

    Science.gov (United States)

    Vidmar, V; Smolcić-Bubalo, A; Jalsenjak, I

    1984-01-01

    Poly(lactic acid) microcapsules of oxytetracycline hydrochloride were prepared by precipitation of the polymer from a solution when a non-solvent was added to a polymer solution in which the drug had been dispersed. Three types of microcapsules were prepared by varying the amount of drug encapsulated, as well as by using two samples of polymer with different molecular weights. The product obtained was of a matrix character consisting of agglomerated capsules. The drug release in vitro, for the best batch, was completed within 12 hours. Serum levels of the drug in rabbits treated by intramuscular injection were prolonged maximally up to 24 hours depending upon the type of microcapsules. PMID:6336522

  17. Influence of different sterilization processes on the properties of commercial poly(lactic acid).

    Science.gov (United States)

    Savaris, M; Santos, V Dos; Brandalise, R N

    2016-12-01

    This study aims at analyzing the modifications in the morphological, physical, chemical and thermal properties of commercial poly(lactic acid) (PLA) films after exposure to five different sterilization processes. Films were obtained by compression molding, hygienized and sterilized by ethylene oxide (SEtO), hydrogen peroxide plasma (SH2O2), saturated steam (SSS), electron beam radiation (SEB) and gamma radiation (SGR). The samples of PLASEtO, PLASH2O2, PLASEB and PLASGR exhibited thermal and physical changes after being submitted to sterilization processes. PLASSS showed morphological, chemical, thermal and physical changes. It is concluded that processes by SEtO, SH2O2, SEB and EGR can be applied for the sterilization of PLA films and the SSS process is not recommended in view of the data obtained and test conditions reported in this study for PLA films. PMID:27612759

  18. Nanostructured Polylactic Acid/Candeia Essential Oil Mats Obtained by Electrospinning

    Directory of Open Access Journals (Sweden)

    Cláudia L. S. de Oliveira Mori

    2015-01-01

    Full Text Available This work aims to evaluate the effect of inclusion of different contents of candeia (Eremanthus erythropappus essential oil (whose alpha-bisabolol is the main terpene on the properties of polylactic acid (PLA nanostructured mats and their relationship with fiber morphology and structure. The interaction occurring between the PLA and the candeia essential oil was confirmed by thermal and microscopy analysis. Addition of candeia essential oil increased nanofiber diameter and decreased the glass transition and melting temperatures of the nanofibers, suggesting lower energy input for processing. Scanning electron microscopy (SEM images provided evidence of a homogeneous structure for the nanostructured mats. X-ray diffraction did not show differences in the crystallization of the nanofibers. This ongoing research confirms the possibility of incorporation of candeia essential oil in the production of nanofibers that will be studied for multipurpose applications.

  19. Clay-filled bio-based blends of poly(lactic acid) and polyamide 11

    Science.gov (United States)

    Nuzzo, Anna; Acierno, Domenico; Filippone, Giovanni

    2012-07-01

    We investigate the effect of small amounts of organoclay on the crystallinity and dynamic-mechanical properties of bio-based blends of poly(lactic acid) (PLA) and polyamide 11 (PA11). Virgin and filled blends were prepared by melt-compounding the constituents using a twin-screw extruder. Wettability considerations suggest that the filler unevenly distribute inside the material. This affect both the crystallinity of each phase and the blend microstructure. Controlling such phenomena can lead to highly "engineerized" materials with tailored properties. In particular, the typically poor mechanical performances of bio-based polymers can be overcame owing to the synergism among reinforcing action of the filler, its possible compatibilizing action and its impact on the crystallinity of the hosting phase.

  20. Properties of polylactic acid composites reinforced with oil palm biomass microcrystalline cellulose.

    Science.gov (United States)

    Haafiz, M K Mohamad; Hassan, Azman; Zakaria, Zainoha; Inuwa, I M; Islam, M S; Jawaid, M

    2013-10-15

    In this work, polylactic acid (PLA) composites filled with microcrystalline cellulose (MCC) from oil palm biomass were successfully prepared through solution casting. Fourier transform infrared (FT-IR) spectroscopy indicates that there are no significant changes in the peak positions, suggesting that incorporation of MCC in PLA did not result in any significant change in chemical structure of PLA. Thermogravimetric analysis was conducted on the samples. The T50 decomposition temperature improved with addition of MCC, showing increase in thermal stability of the composites. The synthesized composites were characterized in terms of tensile properties. The Young's modulus increased by about 30%, while the tensile strength and elongation at break for composites decreased with addition of MCC. Scanning electron microscopy (SEM) of the composites fractured surface shows that the MCC remained as aggregates of crystalline cellulose. Atomic force microscopy (AFM) topographic image of the composite surfaces show clustering of MCC with uneven distribution. PMID:23987327

  1. Effect of synthetic mica on the thermal properties of poly(lactic acid

    Directory of Open Access Journals (Sweden)

    Diego Holanda Saboya Souza

    2014-01-01

    Full Text Available Poly(lactic acid/Somasif fluoromica nanocomposites were prepared by melt blending and their thermal properties investigated by DSC, TGA and DMA. Three different types of synthetic mica (Somasif ME-100, Somasif MAE and Somasif MPE were used at different contents (2.5, 5.0 and 7.5 wt %. The melt blending of PLA and these micas is characterized by a considerable reduction in the matrix molecular weight, which decreases when the nanofiller content is increased. For all nanocomposites, the thermal stability increases when mica is added to the polymer, with the Somasif MPE, producing the highest increase of the degradation temperature and highest reduction of Tg.

  2. Poly(lactic acid) / Poly(ethylene glycol) blends: Mechanical, thermal and morphological properties

    Science.gov (United States)

    Bijarimi, M.; Ahmad, S.; Rasid, R.; Khushairi, M. A.; Zakir, M.

    2016-04-01

    The poly(lactic acid) (PLA) was melt blended with linear polyethylene glycol (PEG) in an effort to increase the toughness of PLA. Melt blending was carried out in an internal mixer at 180 °C mixing temperature with 50 rpm for 15 minutes. The blends were characterized in terms of mechanical, thermal and morphological properties. It was found that tensile and flexural strength, stiffness and notched Izod impact strength decreased significantly when the PEG was added to the PLA matrix at 2.5-10% of PEG concentrations. Both glass transition and melting temperatures (Tg and Tm) lowered as the concentration of PEG was increased. Moreover, it was noted that the PLA/PEG blends showed a lower onset and peak degradation temperatures but with lower final degradation temperature as compared to the neat PLA. The morphological analysis revealed that the PEG was dispersed as droplets in the PLA matrix with a clear boundary between PLA matrix and PEG phases.

  3. A Study of the Crystallization, Melting, and Foaming Behaviors of Polylactic Acid in Compressed CO2

    Directory of Open Access Journals (Sweden)

    Chul B. Park

    2009-12-01

    Full Text Available The crystallization and melting behaviors of linear polylactic acid (PLA treated by compressed CO2 was investigated. The isothermal crystallization test indicated that while PLA exhibited very low crystallization kinetics under atmospheric pressure, CO2 exposure significantly increased PLA’s crystallization rate; a high crystallinity of 16.5% was achieved after CO2 treatment for only 1 min at 100 °C and 6.89 MPa. One melting peak could be found in the DSC curve, and this exhibited a slight dependency on treatment times, temperatures, and pressures. PLA samples tended to foam during the gas release process, and a foaming window as a function of time and temperature was established. Based on the foaming window, crystallinity, and cell morphology, it was found that foaming clearly reduced the needed time for PLA’s crystallization equilibrium.

  4. Preliminary pharmacokinetics of PEGylated oxaliplatin polylactic acid nanoparticles in rabbits and tumor-bearing mice.

    Science.gov (United States)

    Wei, Haitian; Xu, Lisa; Sun, Yong; Li, Gaohong; Cui, Zhaoyuan; Yan, Guowen; Chen, Qian; Yin, Hongli; Ma, Chao

    2015-01-01

    To testify the targeting effect of PEGylated Oxaliplatin polylactic acid (OP-PEG-PLA) nanoparticles (NPs), we studied drug concentration in rabbit plasma and tissue distribution in tumor-bearing mice. Concentration of nanoparticle colloidal solution was performed with dialysis. Qualities of enriched NPs were characterized by particle size and drug content. OP concentration in samples was detected using ICP-MS. Compared to OP solution groups, OP concentration of NPs groups increased in the tumor (p < 0.05) and decreased in the kidney and heart (p < 0.05). Compared to OP-PLA NPs groups, OP concentration of OP-PEG-PLA NPs groups increased in the tumor and decreased in the liver and lung (p < 0.05). The concentrated OP-PEG-PLA NPs are good in clinical application and tumor delivery.

  5. Preparation and characterization of interpenetrating networks based on polyacrylates and poly(lactic acid

    Directory of Open Access Journals (Sweden)

    H. Kaczmarek

    2012-01-01

    Full Text Available Three different, multifunctional acrylic monomers were photopolymerized in a matrix of poly(lactic acid, PLA, using 2-hydroxy-2-methyl-1-phenyl-propan-1-one as a photoinitiator. The kinetics of the photopolymerization of monomers in PLA, studied with Fourier Transform Infrared Spectroscopy, has been compared to analogous processes of pure monomers under the same conditions (room temperature, air atmosphere. Additionally, poly(ethylene glycol was added to acrylate/PLA blends as plasticizer.The highly crosslinked networks obtained were characterized by FTIR and optical microscopy. The amount of insoluble gel has been estimated gravimetrically. It was found that the studied systems are characterized by very high polymerization rate, moreover, efficient grafting of polyacrylates on PLA takes place. The observed morphology indicates the heterogeneity of formed networks. The glass transition temperature of PLA in studied blends has been determined by differential scanning calorimetry.

  6. Porous polylactic acid-silica hybrids: preparation, characterization, and study of mesenchymal stem cell osteogenic differentiation.

    Science.gov (United States)

    Pandis, Christos; Trujillo, Sara; Matos, Joana; Madeira, Sara; Ródenas-Rochina, Joaquín; Kripotou, Sotiria; Kyritsis, Apostolos; Mano, João F; Gómez Ribelles, José Luis

    2015-02-01

    A novel approach to reinforce polymer porous membranes is presented. In the prepared hybrid materials, the inorganic phase of silica is synthesized in-situ and inside the pores of aminolyzed polylactic acid (PLA) membranes by sol-gel reactions using tetraethylorthosilicate (TEOS) and glycidoxypropyltrimethoxysilane (GPTMS) as precursors. The hybrid materials present a porous structure with a silica layer covering the walls of the pores while GPTMS serves also as coupling agent between the organic and inorganic phase. The adjustment of silica precursors ratio allows the modulation of the thermomechanical properties. Culture of mesenchymal stem cells on these supports in osteogenic medium shows the expression of characteristic osteoblastic markers and the mineralization of the extracellular matrix.

  7. Mechanical characterization and morphology of polylactic acid /liquid natural rubber filled with multi walled carbon nanotubes

    Science.gov (United States)

    Ali, Adilah Mat; Ahmad, Sahrim Hj.

    2013-11-01

    In this paper the polymer nanocomposite of multi-walled carbon nanotubes (MWCNTs) nanoparticles was incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer were prepared via melt blending method. The effect of MWCNTs loading on the tensile and impact properties of nanocomposites was investigated. The result has shown that the sample with 3.5 wt % of MWCNTs exhibited higher tensile strength, Young's modulus and impact strength. The elongation at break decreased with increasing percentage of MWCNTs. The SEM micrographs confirmed the effect of good dispersion of MWCNTs and their interfacial bonding in PLA/LNR composites. The improved dispersion of MWCNTs can be obtained due to altered interparticle interactions, MWCNTs-MWCNTs and MWCNTs-matrix networks are well combined to generate the synergistic effect of the system as shown by SEM micrographs which is improved the properties significantly.

  8. Biocompatibility and characterization of polylactic acid/styrene-ethylene-butylene-styrene composites.

    Science.gov (United States)

    Tsou, Chi-Hui; Kao, Bo-Jyue; Yang, Ming-Chien; Suen, Maw-Cherng; Lee, Yi-Hsuan; Chen, Jui-Chin; Yao, Wei-Hua; Lin, Shang-Ming; Tsou, Chih-Yuan; Huang, Shu-Hsien; De Guzman, Manuel; Hung, Wei-Song

    2015-01-01

    Polylactic acid (PLA)/styrene-ethylene-butylene-styrene (SEBS) composites were prepared by melt blending. Differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WXRD) were used to characterize PLA and PLA/SEBS composites in terms of their melting behavior and crystallization. Curves from thermal gravimetric analysis (TGA) illustrated that thermostability increased with SEBS content. Further morphological analysis of PLA/SEBS composites revealed that SEBS molecules were not miscible with PLA molecules in PLA/SEBS composites. The tensile testing for PLA and PLA/SEBS composites showed that the elongation at the break was enhanced, but tensile strength decreased with increasing SEBS content. L929 fibroblast cells were chosen to assess the cytocompatibility; the cell growth of PLA was found to decrease with increasing SEBS content. This study proposes possible reasons for these properties of PLA/SEBS composites.

  9. Study on Dyeing of a Novel, Pro-environment Polylactic Acid (PLA) Fiber Yarn

    Institute of Scientific and Technical Information of China (English)

    FU Ke-jie; MIN Jie; LI Zheng-rong; YANG Li-sheng

    2008-01-01

    Seventeen disperse dyes including anthraquinone, azo, methine, nitro, and quinoline dyes were applied to dye the Polylactic Acid (PLA) yarns at different conditions, and the dyebath exhaustion was determined. The result shows that C.I. disperse red 167, C.I. disperse orange 30, and C.I. disperse blue 284 have dye-uptakes greater than 80%. Therefore, they can be used as the three principal dyes for PLA yams. The experiment discovered that the dyes, because of their Monoazo and ester group contents, have a higher dye-uptake for the PLA fiber. The research on the optimization of dyeing techniques suggests that PLA yarn can obtain a high level of dyeing effectiveness at the following conditions: pH 4-5, dyeing temperture 110℃ for 30- 40 min. Color fastness to perspiration, and water-washing fastness increased 1 - 1. 5 by the addition of the abstergent FB during the reduction clearing.

  10. Effects of electron beam irradiation on the structural properties of polylactic acid/polyethylene blends

    Energy Technology Data Exchange (ETDEWEB)

    Bee, Soo-Tueen, E-mail: direct.beest@gmail.com [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Ratnam, C.T. [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Sin, Lee Tin, E-mail: direct.tinsin@gmail.com [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Tee, Tiam-Ting; Wong, Wai-Kien; Lee, Jiuun-Xiang [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Rahmat, A.R. [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

    2014-09-01

    Highlights: •Electron beam irradiation on polyethylene (LDPE) and polylactic acid (PLA) blends. •Irradiated PLA/LDPE blends exhibit structural rearrangement to highly ordered structure. •Irradiated PLA/LDPE matrix extends continuity of polymer matrix with larger fibrils diameter. -- Abstract: The purpose of this research was to investigate the effects of electron beam irradiation on the properties of polylactic acid (PLA) and low density polyethylene (LDPE) blends. The PLA were compounded with 20–80% LDPE and were exposed to electron beam irradiation dosages of 20–120 kGy. The results from gel content and X-ray diffraction analyses showed that the addition of LDPE to PLA effectively increased the gel content and crystallinity. However, an increasing percentage of LDPE reduced the tensile strength and Young’s modulus of the PLA/LDPE samples due to the lower intermolecular bonding of LDPE than of PLA. Moreover, an increase in irradiation dosages gradually decreased the mechanical properties of low-LDPE PLA/LDPE. In contrast, the increasing irradiation dosage enhanced the mechanical properties of higher-LDPE PLA/LDPE. These results indicate that higher amounts of LDPE effectively react with the release of free radicals within the amorphous phase if the blends are subjected to irradiation. The higher amounts of free radicals induce the formation of three-dimensional cross-linked networks in the polymer matrix and thus increase the gel content. The irradiation-induced cross-linking in PLA/LDPE samples improves the mechanical properties and crystallinity by promoting a structural rearrangement of the polymer matrix into a highly ordered structure.

  11. Preparation of magnetic polylactic acid microspheres and investigation of its releasing property for loading curcumin

    International Nuclear Information System (INIS)

    In order to obtain a targeting drug carrier system, magnetic polylactic acid (PLA) microspheres loading curcumin were synthesized by the classical oil-in-water emulsion solvent-evaporation method. In the Fourier transform infrared spectra of microspheres, the present functional groups of PLA were all kept invariably. The morphology and size distribution of magnetic microspheres were observed with scanning electron microscopy and dynamic light scattering, respectively. The results showed that the microspheres were regularly spherical and the surface was smooth with a diameter of 0.55-0.75 μm. Magnetic Fe3O4 was loaded in PLA microspheres and the content of magnetic particles was 12 wt% through thermogravimetric analysis. The magnetic property of prepared microspheres was measured by vibrating sample magnetometer. The results showed that the magnetic microspheres exhibited typical superparamagnetic behavior and the saturated magnetization was 14.38 emu/g. Through analysis of differential scanning calorimetry, the curcumin was in an amorphous state in the magnetic microspheres. The drug loading, encapsulation efficiency and releasing properties of curcumin in vitro were also investigated by ultraviolet-visible spectrum analysis. The results showed that the drug loading and encapsulation efficiency were 8.0% and 24.2%, respectively. And curcumin was obviously slowly released because the cumulative release percentage of magnetic microspheres in the phosphate buffer (pH=7.4) solution was only 49.01% in 72 h, and the basic release of curcumin finished in 120 h. - Highlights: → We prepare magnetic polylactic acid microspheres loading curcumin. → The classical oil-in-water emulsion solvent-evaporation method is used. → The magnetic microspheres are regularly spherical with a diameter of 0.55-0.75 μm. → They show a certain sustained release effect on in vitro drug releasing.

  12. Preparation of magnetic polylactic acid microspheres and investigation of its releasing property for loading curcumin

    Energy Technology Data Exchange (ETDEWEB)

    Li Fengxia [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China); Li Xiaoli, E-mail: lixiaoli0903@163.com [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China); Li Bin, E-mail: libinzh62@163.com [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China)

    2011-11-15

    In order to obtain a targeting drug carrier system, magnetic polylactic acid (PLA) microspheres loading curcumin were synthesized by the classical oil-in-water emulsion solvent-evaporation method. In the Fourier transform infrared spectra of microspheres, the present functional groups of PLA were all kept invariably. The morphology and size distribution of magnetic microspheres were observed with scanning electron microscopy and dynamic light scattering, respectively. The results showed that the microspheres were regularly spherical and the surface was smooth with a diameter of 0.55-0.75 {mu}m. Magnetic Fe{sub 3}O{sub 4} was loaded in PLA microspheres and the content of magnetic particles was 12 wt% through thermogravimetric analysis. The magnetic property of prepared microspheres was measured by vibrating sample magnetometer. The results showed that the magnetic microspheres exhibited typical superparamagnetic behavior and the saturated magnetization was 14.38 emu/g. Through analysis of differential scanning calorimetry, the curcumin was in an amorphous state in the magnetic microspheres. The drug loading, encapsulation efficiency and releasing properties of curcumin in vitro were also investigated by ultraviolet-visible spectrum analysis. The results showed that the drug loading and encapsulation efficiency were 8.0% and 24.2%, respectively. And curcumin was obviously slowly released because the cumulative release percentage of magnetic microspheres in the phosphate buffer (pH=7.4) solution was only 49.01% in 72 h, and the basic release of curcumin finished in 120 h. - Highlights: > We prepare magnetic polylactic acid microspheres loading curcumin. > The classical oil-in-water emulsion solvent-evaporation method is used. > The magnetic microspheres are regularly spherical with a diameter of 0.55-0.75 {mu}m. > They show a certain sustained release effect on in vitro drug releasing.

  13. Antibacterial Efficiency of Hydroxyapatite Biomaterials with Biodegradable Polylactic Acid and Polycaprolactone Polymers Saturated with Antibiotics / Bionoārdāmu Polimēru Saturošu Un Ar Antibiotiskajām Vielām Piesūcinātu Biomateriālu Antibakteriālās Efektivitātes Noteikšana

    Directory of Open Access Journals (Sweden)

    Kroiča Juta

    2016-08-01

    Full Text Available Infections continue to spread in all fields of medicine, and especially in the field of implant biomaterial surgery, and not only during the surgery, but also after surgery. Reducing the adhesion of bacteria could decrease the possibility of biomaterial-associated infections. Bacterial adhesion could be reduced by local antibiotic release from the biomaterial. In this in vitro study, hydroxyapatite biomaterials with antibiotics and biodegradable polymers were tested for their ability to reduce bacteria adhesion and biofilm development. This study examined the antibacterial efficiency of hydroxyapatite biomaterials with antibiotics and biodegradable polymers against Staphylococcus epidermidis and Pseudomonas aeruginosa. The study found that hydroxyapatite biomaterials with antibiotics and biodegradable polymers show longer antibacterial properties than hydroxyapatite biomaterials with antibiotics against both bacterial cultures. Therefore, the results of this study demonstrated that biomaterials that are coated with biodegradable polymers release antibiotics from biomaterial samples for a longer period of time and may be useful for reducing bacterial adhesion on orthopedic implants.

  14. Effects of a tetracycline blended polylactic and polyglycolic acid membrane on the healing of one-wall intrabony defects in beagle dogs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Il-Young [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Jung, Ui-Won [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Kim, Chang-Sung [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Lee, Yong-Keun [Department and Research Institute of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-750 (Korea, Republic of); Cho, Kyoo-Sung [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Chai, Jung-Kiu [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Kim, Chong-Kwan [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Choi, Seong-Ho [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of)

    2007-09-15

    The purpose of this study was to evaluate the regenerative effects of a tetracycline blended polylactic and polyglycolic acid (TC-PLGA) and non-blended polylactic and polyglycolic acid (PLGA) barrier membrane on one-wall intrabony defects in beagle dogs. It can be concluded that when used for guided tissue regeneration TC-PLGA membranes show a beneficial effect on one-wall intrabony defects in beagle dogs.

  15. Biodegradation of flax fiber reinforced poly lactic acid

    Directory of Open Access Journals (Sweden)

    2010-07-01

    Full Text Available Woven and nonwoven flax fiber reinforced poly lactic acid (PLA biocomposites were prepared with amphiphilic additives as accelerator for biodegradation. The prepared composites were buried in farmland soil for biodegradability studies. Loss in weight of the biodegraded composite samples was determined at different time intervals. The surface morphology of the biodegraded composites was studied with scanning electron microscope (SEM. Results indicated that in presence of mandelic acid, the composites showed accelerated biodegradation with 20–25% loss in weight after 50–60 days. On the other hand, in presence of dicumyl peroxide (as additive, biodegradation of the composites was relatively slow as confirmed by only 5–10% loss in weight even after 80–90 days. This was further confirmed by surface morphology of the biodegraded composites. We have attempted to show that depending on the end uses, we can add different amphiphilic additives for delayed or accelerated biodegradability. This work gives us the idea of biodegradation of materials from natural fiber reinforced PLA composites when discarded carelessly in the environment instead of proper waste disposal site.

  16. Histomorphological researches on large porous hydroxyapatite cylinder tubes with polylactic acid surface coating in different nonskeletal sites in vivo.

    Science.gov (United States)

    Zhang, Cong; Huang, Peng; Weng, Jie; Zhi, Wei; Hu, Yonghe; Feng, Huaizhi; Yao, Yimin; Li, Shuo; Xia, Tian

    2012-05-01

    Porous hydroxyapatite (HA) ceramic cylinder tubes coated with polylactic acid on the exposed surfaces were implanted in four nonskeletal sites (omentum, peritoneum, vastus lateralis, and side of femur). Six months postoperatively, proper amount of Chinese ink was injected to dye the implanting areas. Decalcified and nondecalcified sections were observed under inverted microscope. The results showed that the soft tissues around the HA cylinder tubes in peritoneum, vastus lateralis, and side of femur groups appeared visible black. Some small blacked vascular architectures were also discernible. However in omentum group, only small number of blacked vessels existed. Histological observations indicated that vascularization and ossification occurred in peritoneum, vastus lateralis, and side of femur groups. In omentum group, there was no any sign of vascularization and ossification. A conclusion could be made in this study that excepting bones and muscles, parietal peritoneum could serve as a potential spot for culturing histoengineering hydroxyapatite (HA)-polylactic acid (PLA) ceramic bone substitutes. PMID:22344718

  17. SYNTHESIS AND PROPERTIES OF HIGH MOLECULAR WEIGHT POLY(LACTIC ACID) AND ITS RESULTANT FIBERS

    Institute of Scientific and Technical Information of China (English)

    Wang-xi Zhang; Yan-zhi Wang

    2008-01-01

    Direct melt/solid polycondensation of lactic acid (LA) was carried out to obtain high molecular weight poly(lactic acid) (PLA) by a process using various catalysts in the first-step melt polycondensation, and followed solid polycondensation by using p-toulenesulfonic acid monohydrate (TSA) as the catalyst in the second step. Effects of various catalysts and reaction temperature on the molecular weight and crystallinity of resulting PLA polymers were examined. It was shown that SnCl2·2H2O/TSA, SnCl2·2H2O/succinic anhydride, and SnCl2·2H2O/maleic anhydride binary catalysts should be effective binary catalysts to obtain high molecular weight PLA of more than 1.2 × 105. A conventional melt spinning method was used to spin PLA fibers, which displayed tensile strength of (382.76±1.41) MPa and tensile modulus of (4.36±0.07) GPa.

  18. Preparation and Characterization of Films Extruded of Polyethylene/Chitosan Modified with Poly(lactic acid

    Directory of Open Access Journals (Sweden)

    Jesús Manuel Quiroz-Castillo

    2014-12-01

    Full Text Available The use of mixtures of synthetic and natural polymers is a potential option to reduce the pollution by plastic waste. In this work, the method for the chemical modification of chitosan with poly(lactic acid was developed; then, the preparation of films of blends of polyethylene and chitosan-poly(lactic acid produced by an extrusion method using polyethylene-graft maleic anhydride as a compatibilizer. It was possible to obtain films with a maximum content of 20 wt% and 30 wt%, chitosan, with and without compatibilizer, respectively. Scanning electron microscope (SEM analysis showed a homogeneous surface on all films. The addition of the compatibilizer had a significant effect on the mechanical properties of the films, such as an increase in Young’s modulus and a decrease in the elongation at break; additionally, the compatibilizer promotes thermal degradation in a single step and gives the film a slight increase in thermal resistance. These results are attributed to an improved interaction in the interface of polyethylene and chitosan-poly(lactic acid, promoted by the compatibilizer.

  19. A New Esterase from Thermobifida halotolerans Hydrolyses Polyethylene Terephthalate (PET and Polylactic Acid (PLA

    Directory of Open Access Journals (Sweden)

    Georg Steinkellner

    2012-02-01

    Full Text Available A new esterase from Thermobifida halotolerans (Thh_Est was cloned and expressed in E. coli and investigated for surface hydrolysis of polylactic acid (PLA and polyethylene terephthalate (PET. Thh_Est is a member of the serine hydrolases superfamily containing the -GxSxG- motif with 85–87% homology to an esterase from T. alba, to an acetylxylan esterase from T. fusca and to various Thermobifida cutinases. Thh_Est hydrolyzed the PET model substrate bis(benzoyloxyethylterephthalate and PET releasing terephthalic acid and mono-(2-hydroxyethyl terephthalate in comparable amounts (19.8 and 21.5 mmol/mol of enzyme while no higher oligomers like bis-(2-hydroxyethyl terephthalate were detected. Similarly, PLA was hydrolyzed as indicated by the release of lactic acid. Enzymatic surface hydrolysis of PET and PLA led to a strong hydrophilicity increase, as quantified with a WCA decrease from 90.8° and 75.5° to 50.4° and to a complete spread of the water drop on the surface, respectively.

  20. Combined Effect of Poly(hydroxybutyrate) and Plasticizers on Polylactic acid Properties for Film Intended for Food Packaging

    OpenAIRE

    ARRIETA, Marina Patricia; Samper, María D.; López, Juan; Jiménez, Alfonso

    2014-01-01

    Poly(lactic acid) PLA, and poly(hydroxybutyrate) PHB, blends were processed as films and characterized for their use in food packaging. PLA was blended with PHB to enhance the crystallinity. Therefore, PHB addition strongly increased oxygen barrier while decreased the wettability. Two different environmentally-friendly plasticizers, poly(ethylene glycol) (PEG) and acetyl(tributyl citrate) (ATBC), were added to these blends to increase their processing performance, while improving their ductil...

  1. The Synthesis and Modification of Polylactic Acid%聚乳酸的合成及其改性

    Institute of Scientific and Technical Information of China (English)

    蒲小聪

    2009-01-01

    聚乳酸(polylactic acid,PLA)是以乳酸为单体经化学合成的新型生物降解性高分子材料.本文较全面地介绍了聚乳酸的合成与改性方法,并预示了聚乳酸材料的研究开发前景.

  2. Chemical and Sensory Evaluation of Silicone and Polylactic Acid-Based Remedial Treatments for Elevated Methoxypyrazine Levels in Wine

    Directory of Open Access Journals (Sweden)

    Andreea Botezatu

    2016-09-01

    Full Text Available Alkylmethoxypyrazines (MPs are a class of compounds that can elicit undesirable aroma and flavor characteristics in wine, and resist remediation using traditional wine making approaches. MPs are grape-derived constituents as well as contaminants from Coccinellidae beetles present during wine processing; the latter eliciting an off-flavor referred to as ‘ladybug taint’. In this study we investigated the capacity of two plastic polymers—one silicone-based, the other polylactic acid-based—applied with varying surface areas to reduce concentrations of isopropylmethoxypyrazine (IPMP, sec-butylmethoxypyrazine (SBMP and isobutylmethoxypyrazine (IBMP in a Merlot wine using multi-dimensional gas chromatography coupled with mass spectrometry and headspace solid phase microextraction (SPME-MDGCMS. The impact of treatments on the sensory characteristics of the wine (descriptive analysis and volatile aroma compounds (VOCs (SPME-MDGCMS was also investigated. Results showed substantial reductions for all of the target odorants: up to 38%, 44% and 39% for IPMP, SBMP and IBMP, respectively, for the silicone polymer, and up to 75%, 78% and 77% for IPMP, SBMP and IBMP, respectively, for the polylactic acid polymer. These polymers had no or minimal effect on VOCs at applications of 200 cm2/L for silicone or for all polylactic acid treatments. Sensory impacts were less clear, but generally showed minimal effect from the treatments. Taken overall, the data confirm the utility of both polylactic acid and silicone polymers in reducing elevated levels of grape-derived MPs, as well as potentially improving wine contaminated by ladybug taint.

  3. Development and characterization of a coronary polylactic acid stent prototype generated by selective laser melting.

    Science.gov (United States)

    Flege, Christian; Vogt, Felix; Höges, Simon; Jauer, Lucas; Borinski, Mauricio; Schulte, Vera A; Hoffmann, Rainer; Poprawe, Reinhart; Meiners, Wilhelm; Jobmann, Monika; Wissenbach, Konrad; Blindt, Rüdiger

    2013-01-01

    In-stent restenosis is still an important issue and stent thrombosis is an unresolved risk after coronary intervention. Biodegradable stents would provide initial scaffolding of the stenosed segment and disappear subsequently. The additive manufacturing technology Selective Laser Melting (SLM) enables rapid, parallel, and raw material saving generation of complex 3- dimensional structures with extensive geometric freedom and is currently in use in orthopedic or dental applications. Here, SLM process parameters were adapted for poly-L-lactid acid (PLLA) and PLLA-co-poly-ε-caprolactone (PCL) powders to generate degradable coronary stent prototypes. Biocompatibility of both polymers was evidenced by assessment of cell morphology and of metabolic and adhesive activity at direct and indirect contact with human coronary artery smooth muscle cells, umbilical vein endothelial cells, and endothelial progenitor cells. γ-sterilization was demonstrated to guarantee safety of SLM-processed parts. From PLLA and PCL, stent prototypes were successfully generated and post-processing by spray- and dip-coating proved to thoroughly smoothen stent surfaces. In conclusion, for the first time, biodegradable polymers and the SLM technique were combined for the manufacturing of customized biodegradable coronary artery stent prototypes. SLM is advocated for the development of biodegradable coronary PLLA and PCL stents, potentially optimized for future bifurcation applications.

  4. Development and characterization of a coronary polylactic acid stent prototype generated by selective laser melting.

    Science.gov (United States)

    Flege, Christian; Vogt, Felix; Höges, Simon; Jauer, Lucas; Borinski, Mauricio; Schulte, Vera A; Hoffmann, Rainer; Poprawe, Reinhart; Meiners, Wilhelm; Jobmann, Monika; Wissenbach, Konrad; Blindt, Rüdiger

    2013-01-01

    In-stent restenosis is still an important issue and stent thrombosis is an unresolved risk after coronary intervention. Biodegradable stents would provide initial scaffolding of the stenosed segment and disappear subsequently. The additive manufacturing technology Selective Laser Melting (SLM) enables rapid, parallel, and raw material saving generation of complex 3- dimensional structures with extensive geometric freedom and is currently in use in orthopedic or dental applications. Here, SLM process parameters were adapted for poly-L-lactid acid (PLLA) and PLLA-co-poly-ε-caprolactone (PCL) powders to generate degradable coronary stent prototypes. Biocompatibility of both polymers was evidenced by assessment of cell morphology and of metabolic and adhesive activity at direct and indirect contact with human coronary artery smooth muscle cells, umbilical vein endothelial cells, and endothelial progenitor cells. γ-sterilization was demonstrated to guarantee safety of SLM-processed parts. From PLLA and PCL, stent prototypes were successfully generated and post-processing by spray- and dip-coating proved to thoroughly smoothen stent surfaces. In conclusion, for the first time, biodegradable polymers and the SLM technique were combined for the manufacturing of customized biodegradable coronary artery stent prototypes. SLM is advocated for the development of biodegradable coronary PLLA and PCL stents, potentially optimized for future bifurcation applications. PMID:23053808

  5. 聚乳酸纤维包芯纱的开发%Development of Polylactic Acid Fiber Core Spun Yarn

    Institute of Scientific and Technical Information of China (English)

    樊愈波; 郭建生

    2011-01-01

    探讨聚乳酸纤维包芯纱的生产工艺.阐述了在环锭细纱机上纺制聚乳酸纤维包芯纱的方法及各生产工序的工艺要点,并通过正交试验确定了纱线捻度和细纱后区牵伸倍数的最优工艺配置,最终顺利纺制出了21.4 tex(55.6 dtex)聚乳酸纤维包芯纱,质量达到了较好水平.%Processing of polylactic acid fiber core spun yarn was discussed. Spinning method and key technology in each process of spinning polylactic acid fiber core spun yarn on ring spinning frame were introduced. The best optimization of yarn twist and multiples in back zone were selected through orthogonal test. Finally 21.4 tex(55.6 dtex) polylactic acid fiber core spun yarn can be spun successfully, the yam quality can reach better level.

  6. Study Progress of Polylactic Acid Foamed Plastics%聚乳酸泡沫塑料的研究进展

    Institute of Scientific and Technical Information of China (English)

    杨志云; 蔡业彬; 张铱鈖

    2014-01-01

    This paper reviews the progress in studies on polylactic acid foamed plastics ,namely the environmental foamed plastics .It in-cludes the studies researched by the domestic and overseas scholars on the polylactic acid foaming performance ,process conditions ,bubble hole form and so on .Some existing problems are put forward and the study on polylactic acid foamed technology in the future is prospected in this paper .Continuous extrusion of microcellular foam of polyactic (PLA) will be the goal and direction in the future .To achieve the goal will accelerate the industrialization process of microcellular plastics polyactic (PLA) .%文章介绍了环保型泡沫塑料---聚乳酸泡沫塑料当前的研究进展,主要包括国内外学者对聚乳酸的发泡性能、工艺条件和泡孔形态等研究,并提出了目前存在的问题,对未来聚乳酸发泡技术的研究进行了展望。连续挤出微孔的聚乳酸泡沫塑料将成为未来的研究热点和方向,其不断发展也将加快推动聚乳酸微孔塑料的工业化进程。

  7. 聚乳酸合成技术研究进展%Research progress in polylactic acid synthesis

    Institute of Scientific and Technical Information of China (English)

    胡建军

    2012-01-01

    Polylactic acid(PLA) has attracted great attention because of its biodegradability,excellent functional performance and wide application area.Two kinds of chemical synthetic methods of PLA,ring-opening polymerization of lactide(ROPL) and condensation polymerization of lactic acid(CPLA),are reviewed.High molecular weight PLA can be obtained with simple equipment by ROPL route,whereas high cost,complicated technique and long procedure are associated.Alternatively,CPLA route is favorable on the basis of abundant source of cheap raw material,high monomer conversion rate and simple synthetic technique.Meanwhile,the process of intermediate purification is not needed,which leads to low production cost.However,high molecular weight polymer cannot be obtained by this route.Currently,the important research area of PLA includes developing new synthetic technology to further reduce the manufacturing cost.It is imperative to make a breakthrough to find a simple and easy way to prepare PLA with high molecular weight.%聚乳酸因可生物降解、性能优异、应用广泛而深受青睐。本文介绍了2种主要化学合成聚乳酸的方法:丙交酯开环聚合法和乳酸直接缩聚法。分析了这2种方法的优势和缺陷:丙交酯开环聚合法设备简单,可得到大分子量的聚乳酸,缺点是成本较高,整个工艺复杂,路线长;乳酸直接缩聚法原料乳酸来源充足,价格便宜,单体转化率较高,工艺简单,不需要经过中间体的纯化,因而成本较低,缺陷是较难得到高分子量的聚合物。文中指出积极开展聚乳酸的合成工艺研发、进一步降低生产成本是当前聚乳酸研究的重要课题,重点在于简单易行的高分子量聚乳酸合成工艺的突破。

  8. The Recent Advances in Development of Lactic Acid and Polylactic Acid%乳酸和聚乳酸的最新进展

    Institute of Scientific and Technical Information of China (English)

    刘伟雄

    2001-01-01

    The recent advances in the fermentation production of lactic acid with different microorganisms, recovery and detection of lactic acid, and the production of polylactic acid are reviewed in this paper.%综述了不同的产酸菌发酵生产乳酸、乳酸的提取与检测以及聚乳酸的生产等方面的最新进展。

  9. Effect of Sterilization Methods on Electrospun Poly(lactic acid) (PLA) Fiber Alignment for Biomedical Applications.

    Science.gov (United States)

    Valente, T A M; Silva, D M; Gomes, P S; Fernandes, M H; Santos, J D; Sencadas, V

    2016-02-10

    Medically approved sterility methods should be a major concern when developing a polymeric scaffold, mainly when commercialization is envisaged. In the present work, poly(lactic acid) (PLA) fiber membranes were processed by electrospinning with random and aligned fiber alignment and sterilized under UV, ethylene oxide (EO), and γ-radiation, the most common ones for clinical applications. It was observed that UV light and γ-radiation do not influence fiber morphology or alignment, while electrospun samples treated with EO lead to fiber orientation loss and morphology changing from cylindrical fibers to ribbon-like structures, accompanied to an increase of polymer crystallinity up to 28%. UV light and γ-radiation sterilization methods showed to be less harmful to polymer morphology, without significant changes in polymer thermal and mechanical properties, but a slight increase of polymer wettability was detected, especially for the samples treated with UV radiation. In vitro results indicate that both UV and γ-radiation treatments of PLA membranes allow the adhesion and proliferation of MG 63 osteoblastic cells in a close interaction with the fiber meshes and with a growth pattern highly sensitive to the underlying random or aligned fiber orientation. These results are suggestive of the potential of both γ-radiation sterilized PLA membranes for clinical applications in regenerative medicine, especially those where customized membrane morphology and fiber alignment is an important issue. PMID:26756809

  10. Development and characterization of sugar palm starch and poly(lactic acid) bilayer films.

    Science.gov (United States)

    Sanyang, M L; Sapuan, S M; Jawaid, M; Ishak, M R; Sahari, J

    2016-08-01

    The development and characterization of environmentally friendly bilayer films from sugar palm starch (SPS) and poly(lactic acid) (PLA) were conducted in this study. The SPS-PLA bilayer films and their individual components were characterized for their physical, mechanical, thermal and water barrier properties. Addition of 50% PLA layer onto 50% SPS layer (SPS50-PLA50) increased the tensile strength of neat SPS film from 7.74 to 13.65MPa but reduced their elongation at break from 46.66 to 15.53%. The incorporation of PLA layer significantly reduced the water vapor permeability as well as the water uptake and solubility of bilayer films which was attributed to the hydrophobic characteristic of the PLA layer. Furthermore, scanning electron microscopy (SEM) image of SPS50-PLA50 revealed lack of strong interfacial adhesion between the SPS and PLA. Overall, the incorporation of PLA layer onto SPS films enhances the suitability of SPS based films for food packaging. PMID:27112848

  11. Processing and characterization of poly(lactic acid based bioactive composites for biomedical scaffold application

    Directory of Open Access Journals (Sweden)

    J. Goswami

    2013-09-01

    Full Text Available The current study focuses on three-components material systems (poly(lactic acid (PLA, poly(ε-caprolactone (PCL and wollastonite (W in view of possible application a biomedical scaffold constructs. Melt extruded PLA/PCL/W composites (PLCL15, PLCLW1, PLCLW4, PLCLW8 containing 0, 1, 4, 8 phr filler respectively are batch foamed using compressed CO2 and the porous foams are studied for in vitro biocompatibility by seeding osteoblast cells. SEM images of the unfoamed polymers show immiscibility in all compositions. Materials have been tested under compressive load using dry and wet conditions (using phosphate buffered saline at pH 7.4 for in vitro study. Contact angle measurement shows enhanced hydrophilicity in the composites changing from 80° in PLCL15 to 72° in PLCLW8. The foams are found to be microcellular (5–8 µm in morphology showing quite uniform pore distribution in the composites. The prepared foams, when studied as scaffold constructs, show osteoblast cell attachment and proliferation over the incubation period of 7 days. As expected, PLCLW8 containing highest amount of CaSiO3 supported maximum cell growth on its surface as visible from MTT assay data and SEM scans.

  12. Preparation and Properties of Cross-Linked Starch Nanocrystals/Polylactic Acid Nanocomposites

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    Zuodong Yin

    2015-01-01

    Full Text Available Cross-linked starch nanocrystals (CStN/polylactic acid (PLA nanocomposites were prepared by blending CStN and PLA, wherein CStN were homogeneously dispersed in the nanocomposites. The structure and morphology of the nanocomposites were studied through FTIR, XRD, and SEM. The results of mechanical test showed that the strength and toughness of the nanocomposites could be improved when the additive amount of hydrophobic CStN was 3% (weight ratio. Meanwhile, the microstructures of tensile fracture surface showed that CStN were uniformly dispersed in PLA matrix, and the tensile fracture surface was presented as ductile fracture. Moreover, water vapor permeability experiments illustrated that the addition of CStN reduced the water vapor permeability of PLA nanocomposites, so CStN have some resistance to water vapor. Those above indicated that CStN have functions of reinforcement and toughness in PLA matrix; therefore, they are expected to be used as functional additives in polymer matrix such as PLA, polycaprolactone (PCL, and polybutylene succinate (PBS.

  13. Interactions, structure and properties in poly(lactic acid/thermoplastic polymer blends

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    B. Imre

    2014-01-01

    Full Text Available Blends were prepared from poly(lactic acid (PLA and three thermoplastics, polystyrene (PS, polycarbonate (PC and poly(methyl methacrylate (PMMA. Rheological and mechanical properties, structure and component interactions were determined by various methods. The results showed that the structure and properties of the blends cover a relatively wide range. All three blends have heterogeneous structure, but the size of the dispersed particles differs by an order of magnitude indicating dissimilar interactions for the corresponding pairs. Properties change accordingly, the blend containing the smallest dispersed particles has the largest tensile strength, while PLA/PS blends with the coarsest structure have the smallest. The latter blends are also very brittle. Component interactions were estimated by four different methods, the determination of the size of the dispersed particles, the calculation of the Flory-Huggins interaction parameter from solvent absorption, from solubility parameters, and by the quantitative evaluation of the composition dependence of tensile strength. All approaches led to the same result indicating strong interaction for the PLA/PMMA pair and weak for PLA and PS. A general correlation was established between interactions and the mechanical properties of the blends.

  14. Cross-Linking Poly(lactic acid) Film Surface by Neutral Hyperthermal Hydrogen Molecule Bombardment.

    Science.gov (United States)

    Du, Wangli; Shao, Hong; He, Zhoukun; Tang, Changyu; Liu, Yu; Shen, Tao; Zhu, Yan; Lau, Woon-ming; Hui, David

    2015-12-16

    Constructing a dense cross-linking layer on a polymer film surface is a good way to improve the water resistance of poly(lactic acid) (PLA). However, conventional plasma treatments have failed to achieve the aim as a result of the unavoidable surface damage arising from the charged species caused by the uncontrolled high energy coming from colliding ions and electrons. In this work, we report a modified plasma method called hyperthermal hydrogen-induced cross-linking (HHIC) technology to construct a dense cross-linking layer on PLA film surfaces. This method produces energy-controlled neutral hyperthermal hydrogen, which selectively cleaves C-H bonds by molecule collision from the PLA film without breaking other bonds (e.g., C-C bonds in the polymer backbone), and results in subsequent cross-linking of the carbon radicals generated from the organic molecules. The formation of a dense cross-linking layer can serve as a barrier layer to significantly improve both the hydrophobicity and water vapor barrier property of the PLA film. Because of the advantage of selective cleavage of C-H bonds by HHIC treatment, the original physical properties (e.g., mechanical strength and light transmittance) of the PLA films are well-preserved.

  15. Crystalline structure of annealed polylactic acid and its relation to processing

    Directory of Open Access Journals (Sweden)

    2010-10-01

    Full Text Available This paper focuses on the crystalline structure of injection moulding grade poly(lactic acid (PLA and the effect of crystalline structure on the processing. The research is induced by the significant differences in crystallinity of the pure PLA resin, and the injection moulded product, and thus the reprocessing of PLA products. 2 mm thick PLA sheets were injection moulded and re-crystallized in a conventional oven at 60–140°C, for 10–60 minutes to achieve various crystalline contents. The properties of these sheets were investigated by dynamic mechanical analysis (DMA, differential scanning calorimetry (DSC, and wide angle X-ray diffraction (WAXD. In a processing plant the rejected parts are recycled and reused as raw material for further cycles, accordingly the various crystalline content PLA products were reprocessed as a resin, to investigate the processing itself. When PLA products are reprocessed, due to the adherent feature of amorphous PLA processing difficulties may occur. This adherent effect of the amorphous PLA was investigated and characterized.

  16. Mechanical Properties of Poly(lactic acid Sheet Reinforced with Microfibrillated Cellulose from Corn Cobs

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    Deejam Prapatsorn

    2015-01-01

    Full Text Available In this study, cellulose was extracted from corn cobs by successive hot NaOH solution and followed by H2O2 bleaching. XRD pattern show characteristic peak of Cellulose I. Microfibrillated cellulose (MFC was successfully prepared by dissolving the extracted cellulose in NaOH/urea solution, shearing in a homogenizer and finally by freezing and thawing. To improve strength of MFC, MFC was physically crosslinked using PVA by freezing and thawing. The crosslinked MFC/PVA was added to poly(lactic acid (PLA to improve its mechanical properties. The non-crosslinked MFC/PVA was also prepared by only stirring the solution without freezing and thawing. MFC/PVA reinforced PLA films with various ratios of PLA and MFC/PVA at100:0, 99:1, 97:3 and 95:5were prepared through a solution casting method. Tensile strength and elongation at breakof PLA films increased with the addition of physically crosslinked MFC/PVA at 1%wt, whereas, the addition of non-crosslinked MFC/PVA decreased elongation at break. Crosslinking of MFC/PVA can improve tensile strength of PLA.It can render better tensile strength than that of non-crosslinked MFC/PVA. However, when MFC/PVA contents increase, tensile strength of PLA fims reinforced with non-crosslinked and crosslinked MFC/PVA decreased. Morphology of fracture surfaces reveals good dispersion and adhesion between 1% crosslinked MFC/PVA and PLA matrix.

  17. Porous bead-on-string poly(lactic acid) fibrous membranes for air filtration.

    Science.gov (United States)

    Wang, Zhe; Zhao, Chuchu; Pan, Zhijuan

    2015-03-01

    Porous bead-on-string poly(lactic acid) (PLA) nanofibrous membranes (NMs) were fabricated by electrospinning, and the formation mechanism of the membranes was determined in this study. The PLA fibrous morphology, including the fiber diameter, bead size, number of beads, and surface structure of the beads, could be closely controlled by regulating the solvent compositions and the concentrations of the PLA solutions. The filtration performance, which was evaluated by measuring the penetration of sodium chloride (NaCl) aerosol particles with an average diameter of 260nm, indicated that the filtration efficiency and pressure drop for the resultant PLA membranes could be manipulated by modifying the morphology of the fibers. Moderate bead size and quantity contribute to the low pressure drop, and small fiber diameters and nanopores on the beads were conducive to high filtration efficiency. Furthermore, the NM formed from a 5 wt% solution and a solvent mixture containing dichloromethane (DCM)/N,N-dimethylacetamide (DMAC) in a 10/1 ratio of PLA by weight exhibited excellent filtration efficiency (99.997%) and a low pressure drop (165.3 Pa), which are promising characteristics for the membranes' application as filters for respiratory protection, indoor air purification, and other filtration applications. PMID:25499733

  18. Electrospun polylactic acid and polyvinyl alcohol fibers as efficient and stable nanomaterials for immobilization of lipases.

    Science.gov (United States)

    Sóti, Péter Lajos; Weiser, Diana; Vigh, Tamás; Nagy, Zsombor Kristóf; Poppe, László; Marosi, György

    2016-03-01

    Electrospinning was applied to create easy-to-handle and high-surface-area membranes from continuous nanofibers of polyvinyl alcohol (PVA) or polylactic acid (PLA). Lipase PS from Burkholderia cepacia and Lipase B from Candida antarctica (CaLB) could be immobilized effectively by adsorption onto the fibrous material as well as by entrapment within the electrospun nanofibers. The biocatalytic performance of the resulting membrane biocatalysts was evaluated in the kinetic resolution of racemic 1-phenylethanol (rac-1) and 1-phenylethyl acetate (rac-2). Fine dispersion of the enzymes in the polymer matrix and large surface area of the nanofibers resulted in an enormous increase in the activity of the membrane biocatalyst compared to the non-immobilized crude powder forms of the lipases. PLA as fiber-forming polymer for lipase immobilization performed better than PVA in all aspects. Recycling studies with the various forms of electrospun membrane biocatalysts in ten cycles of the acylation and hydrolysis reactions indicated excellent stability of this forms of immobilized lipases. PLA-entrapped lipases could preserve lipase activity and enantiomer selectivity much better than the PVA-entrapped forms. The electrospun membrane forms of CaLB showed high mechanical stability in the repeated acylations and hydrolyses than commercial forms of CaLB immobilized on polyacrylamide beads (Novozyme 435 and IMMCALB-T2-150). PMID:26724947

  19. Physical changes of poly(lactic acid) induced by water sorption

    Science.gov (United States)

    Pantani, Roberto; De Santis, Felice

    2015-12-01

    One of the main limits to the use of Poly(Lactic Acid), PLA, is its extreme sensitivity to moisture. The objective of this work is to study the physical changes induced by water sorption on a commercial PLA grade. To this goal, samples of PLA having thickness of about 400 µm, obtained by compression molding, were put into contact with water at 58 °C. The samples were partially immersed in water in a closed and mixed vessel, so that the lower part was in contact with liquid water whereas the upper part was in contact with air with a relative humidity of 100%. The opacity of the samples, their crystallinity degree, their density and molecular weight were monitored during time. It was found that the samples became white and opaque after a few hours, crystallinity reached an equilibrium value after about 48 h. Density was found to decrease with time, thus suggesting that the whitening was due to crazing. Surprisingly, it was found that the mentioned phenomena are more evident for the samples immersed in water than for those surrounded by a 100% RH atmosphere.

  20. Barrier Properties of Polylactic Acid in Cellulose Based Packages Using Montmorillonite as Filler

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    Daniela Sánchez Aldana

    2014-09-01

    Full Text Available Polylactic acid (PLA and montmorillonite (CB as filler were studied as coatings for cellulose based packages. Amorphous (AM and semi crystalline (SC PLA were used at different concentrations according to a 2 × 6 × 3 full factorial experimental design. CB loading was three concentrations and coating was performed by casting. Contact angle (CA, water vapor (WVP and grease permeabilities were measured for each resultant package and were compared to commercial materials (Glassine Paper, Grease Proof Papers 1 and 2 produced commercially. Significant differences were found and the main factors were the type and concentration of PLA. The best values were: for grease penetration, +1800 s; WVP from 161.36 to 237.8 g·µm·kPa−1·m−2·d−1 and CA from 69° to 73° for PLA–AM 0.5% and CB variable. These parameters are comparable to commercial packages used in the food industry. DSC revealed three different thermal events for PLA–SC and just Tg for PLA–AM. Crystallinity was also verified, obtaining a ΔHcrys of 3.7 J·g−1 for PLA–SC and 14 J·g−1 for PLA–SC–BC, evidencing clay interaction as a crystal nucleating agent. Differences found were explained on terms of the properties measured, where structural and chemical arrays of the coatings play a fundamental role for the barrier properties.

  1. Surface Resistance of Jute Fibre/Polylactic Acid Biocomposite to Wet Heat

    Science.gov (United States)

    Zandvliet, Clio; Bandyopadhyay, N. R.; Ray, Dipa

    2016-04-01

    Jute fibre/polylactic acid (PLA) composite is of special interest because both resin and reinforcement come from renewable resources. Thus, it could be a more eco-friendly alternative to glass fibre composite [1] and to conventional wood-based panels made with phenol-formaldehyde resin which present many drawbacks for the workers and the environment [2]. Yet the water affinity of the natural fibres, the susceptibility of PLA towards hydrolysis and the low glass transition of the PLA raise a question about the surface resistance of such composites to wet heat in service condition for a furniture application [3]. In this work, the surface resistance of PLA/jute composite alone and with two different varnishes are investigated in regard to an interior application following the standard test method in accordance to BS EN 18721:2009: "Furniture: assessment of surface resistance to wet heat". It is compared to two common wood based panels, plywood and hardboard. After test, the composite material surface is found to be more affected than plywood and hardboard, but it becomes resistant to wet heat when a layer of biosourced varnish or petrol-based polyurethane varnish are applied on the surface.

  2. Osteogenic and osteoclastogenic differentiation of co-cultured cells in polylactic acid-nanohydroxyapatite fiber scaffolds.

    Science.gov (United States)

    Morelli, Sabrina; Salerno, Simona; Holopainen, Jani; Ritala, Mikko; De Bartolo, Loredana

    2015-06-20

    The design of bone substitutes involves the creation of a microenvironment supporting molecular cross-talk between cells and scaffolds during tissue formation and remodelling. Bone remodelling process includes the cooperation of bone-building cells and bone-resorbing cells. In this paper we developed polylactic acid (PLA) and composite PLA-nanohydroxyapatite (nHA) scaffolds with 20 and 50wt.% of nHA by electrospinning technique to be used in bone tissue engineering. The developed scaffolds have different fiber diameter, porosity with interconnected pores and mechanical properties. Taking cues from the bone environment features we investigated the differentiation of human mesenchymal stem cells (hMSCs) from bone marrow in osteoblasts and the osteoclastogenesis in the developed scaffolds in homotypic and in co-culture up to 46 days. PLA and composite PLA-nHA scaffolds induced osteogenic and osteoclastogenic differentiation. Both osteoblasts and osteoclasts displayed high expression of specific markers (osteopontin, osteocalcin, RANK, RANKL) and functions such as secretion of ALP, cathepsin K and TRAP activity on composite scaffolds especially on PLA-nHA containing 20wt.% of nHA. The heterotypic interactions between osteoblasts and osteoclasts co-cultured in the developed scaffolds triggered their functional differentiation and activation.

  3. Polylactic acid with improved heat deflection temperatures and self-healing properties for durable goods applications.

    Science.gov (United States)

    Wertz, J T; Mauldin, T C; Boday, D J

    2014-11-12

    A method to recover fracture toughness after failure and increase thermal properties of polylactic acid (PLA) for use within durable goods applications is presented. Microcapsules were incorporated into PLA to form a composite material in which the microcapsules served the dual purpose of (1) releasing self-healing additives to fracture regions and (2) serving as nucleating agents to improve the PLA composite's thermal tolerance. Self-healing was achieved though embedment of dicyclopentadiene-filled microcapsules and Grubbs' first generation ruthenium metathesis catalyst, the former being autonomically released into damage volumes and undergoing polymerization in the presence of the catalyst. This approach led to up to 84% recovery of the polymer composite's initial fracture toughness. Additionally, PLA's degree of crystallinity and heat deflection temperature were improved by ∼ 11% and ∼ 21 °C, respectively, relative to nonfilled virgin PLA, owing to microcapsule-induced nucleation. The self-healing system developed here overcomes many property limitations of PLA that can potentially lead to its incorporation into various durable goods.

  4. Anticancer studies of drug encapsulated polyethylene terephthalate-Co-polylactic acid nanocapsules

    Directory of Open Access Journals (Sweden)

    K Sathish Kumar

    2011-01-01

    Full Text Available Objectives: The purpose of this study was to investigate the anticancer activity of anticancer drugs (5-fluorouracil and 6-thioguanine in polymeric nanocapsules in the presence and in the absence of gold and iron oxide nanoparticles toward Hep2 cancer cells. Materials and Methods: MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay was used for quantitative measurements for the anticancer cell activity. Encapsulated drug in polyethylene terephthalate-polylactic acid copolymer (PET-co-PLA nanocapsules in the presence and absence of gold and iron oxide nanoparticles were prepared via the W/O/W emulsification solvent-evaporation method. Morphology of the nanoparticles was characterized by transmission electron microscopy and scanning electron microscopy. Conclusion: The average size of the polymeric nanocapsules, gold nanoparticles, and iron oxide nanoparticles were found to be in range of 230-260, 18 -20 nm, 5-10 nm, respectively. The findings in this study inferred that incorporated drug in polymeric nanocapsules with gold nanoparticles and iron oxide nanoparticles show better anticancer activity when compared with encapsulated drug in polymeric nanocapsules.

  5. Effects of polylactic acid film on middle ear mucosa and cochlear function in Guinea pigs.

    Science.gov (United States)

    Ensari, Nuray; Tutar, Hakan; Ekinci, Ozgur; Ugur, Mehmet Birol; Bayazıt, Yıldırım A; Gokdogan, Cagil; Goksu, Nebil

    2015-05-01

    Our aim was to assess the effects of polylactic acid (PLA) on middle ear mucosa and cochlea, to be used as a film barrier for postoperative adhesion prevention in the middle ear. Twenty-one albino Guinea pigs were included in the study. A window was opened on both tympanic bulla and on one side PLA material was placed in the middle ear and on the other side only fenestration was performed and used as a control. All Guinea pigs underwent evaluation of tympanic membranes microscopically; functional hearing was analyzed by auditory brainstem responses preoperatively, in the first and the sixth month. All Guinea pigs were killed on the sixth month for histopathologic evaluation of their temporal bones. There was no statistical difference between both groups regarding hearing thresholds, interpeak wave latencies preoperatively and on first and the sixth months postoperatively. Histopathological evaluation revealed no specific changes. There was a mild local inflammation both in the PLA implanted and control ears. PLA film barrier most likely has no toxic effects on Guinea pig middle ear and does not show any ototoxic side effects.

  6. Epoxidized Vegetable Oils Plasticized Poly(lactic acid Biocomposites: Mechanical, Thermal and Morphology Properties

    Directory of Open Access Journals (Sweden)

    Buong Woei Chieng

    2014-10-01

    Full Text Available Plasticized poly(lactic acid PLA with epoxidized vegetable oils (EVO were prepared using a melt blending method to improve the ductility of PLA. The plasticization of the PLA with EVO lowers the Tg as well as cold-crystallization temperature. The tensile properties demonstrated that the addition of EVO to PLA led to an increase of elongation at break, but a decrease of tensile modulus. Plasticized PLA showed improvement in the elongation at break by 2058% and 4060% with the addition of 5 wt % epoxidized palm oil (EPO and mixture of epoxidized palm oil and soybean oil (EPSO, respectively. An increase in the tensile strength was also observed in the plasticized PLA with 1 wt % EPO and EPSO. The use of EVO increases the mobility of the polymeric chains, thereby improving the flexibility and plastic deformation of PLA. The SEM micrograph of the plasticized PLA showed good compatible morphologies without voids resulting from good interfacial adhesion between PLA and EVO. Based on the results of this study, EVO may be used as an environmentally friendly plasticizer that can improve the overall properties of PLA.

  7. Effects of electron beam irradiation on the structural properties of polylactic acid/polyethylene blends

    Science.gov (United States)

    Bee, Soo-Tueen; Ratnam, C. T.; Sin, Lee Tin; Tee, Tiam-Ting; Wong, Wai-Kien; Lee, Jiuun-Xiang; Rahmat, A. R.

    2014-09-01

    The purpose of this research was to investigate the effects of electron beam irradiation on the properties of polylactic acid (PLA) and low density polyethylene (LDPE) blends. The PLA were compounded with 20-80% LDPE and were exposed to electron beam irradiation dosages of 20-120 kGy. The results from gel content and X-ray diffraction analyses showed that the addition of LDPE to PLA effectively increased the gel content and crystallinity. However, an increasing percentage of LDPE reduced the tensile strength and Young's modulus of the PLA/LDPE samples due to the lower intermolecular bonding of LDPE than of PLA. Moreover, an increase in irradiation dosages gradually decreased the mechanical properties of low-LDPE PLA/LDPE. In contrast, the increasing irradiation dosage enhanced the mechanical properties of higher-LDPE PLA/LDPE. These results indicate that higher amounts of LDPE effectively react with the release of free radicals within the amorphous phase if the blends are subjected to irradiation. The higher amounts of free radicals induce the formation of three-dimensional cross-linked networks in the polymer matrix and thus increase the gel content. The irradiation-induced cross-linking in PLA/LDPE samples improves the mechanical properties and crystallinity by promoting a structural rearrangement of the polymer matrix into a highly ordered structure.

  8. Characterization of hydrolytic degradation of polylactic acid/rice hulls composites in water at different temperatures

    Directory of Open Access Journals (Sweden)

    2011-02-01

    Full Text Available Hydrolytic degradations of polylactic acid/rice hulls (PLA/RH composites with various rice hulls contents due to water absorptions at 23, 51 and 69°C were investigated by studying the thermal properties, chemical composition, molecular weight, and morphology of the degraded products. The results have attested that the stability of PLA/RH composites in water depends slightly on rice hulls contents but it is significantly influenced by water temperature. Water absorption in 30 days at 23°C was between 0.87 and 9.25% depending on rice hull contents. However, at thermophilic temperatures, the water absorption and degradation of these products were increased significantly. Saturations were achieved in less than 25 and 9 days at 51°C and 69°C, respectively, while hydrolytic degradation was demonstrated by an increase in fragility and development of crystallinity. At 69°C, there were significant reductions of the decomposition and glass transition temperatures of the polymer by 13°C. These changes were associated with the reduction of the molecular weight of PLA from 153.1 kDa to ~10.7 kDa due to hydrolysis of its ester group.

  9. Electrospun polylactic acid and polyvinyl alcohol fibers as efficient and stable nanomaterials for immobilization of lipases.

    Science.gov (United States)

    Sóti, Péter Lajos; Weiser, Diana; Vigh, Tamás; Nagy, Zsombor Kristóf; Poppe, László; Marosi, György

    2016-03-01

    Electrospinning was applied to create easy-to-handle and high-surface-area membranes from continuous nanofibers of polyvinyl alcohol (PVA) or polylactic acid (PLA). Lipase PS from Burkholderia cepacia and Lipase B from Candida antarctica (CaLB) could be immobilized effectively by adsorption onto the fibrous material as well as by entrapment within the electrospun nanofibers. The biocatalytic performance of the resulting membrane biocatalysts was evaluated in the kinetic resolution of racemic 1-phenylethanol (rac-1) and 1-phenylethyl acetate (rac-2). Fine dispersion of the enzymes in the polymer matrix and large surface area of the nanofibers resulted in an enormous increase in the activity of the membrane biocatalyst compared to the non-immobilized crude powder forms of the lipases. PLA as fiber-forming polymer for lipase immobilization performed better than PVA in all aspects. Recycling studies with the various forms of electrospun membrane biocatalysts in ten cycles of the acylation and hydrolysis reactions indicated excellent stability of this forms of immobilized lipases. PLA-entrapped lipases could preserve lipase activity and enantiomer selectivity much better than the PVA-entrapped forms. The electrospun membrane forms of CaLB showed high mechanical stability in the repeated acylations and hydrolyses than commercial forms of CaLB immobilized on polyacrylamide beads (Novozyme 435 and IMMCALB-T2-150).

  10. Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

    Directory of Open Access Journals (Sweden)

    Chern Chiet Eng

    2013-01-01

    Full Text Available The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA/Polycaprolactone (PCL blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD, Fourier Transform Infrared Spectroscopy (FTIR, Thermogravimetric Analysis (TGA, Dynamic Mechanical Analysis (DMA, Scanning Electron Microscopy (SEM, and Transmission Electron Microscopy (TEM. FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two Tg of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology.

  11. Natamycin based sol-gel antimicrobial coatings on polylactic acid films for food packaging.

    Science.gov (United States)

    Lantano, Claudia; Alfieri, Ilaria; Cavazza, Antonella; Corradini, Claudio; Lorenzi, Andrea; Zucchetto, Nicola; Montenero, Angelo

    2014-12-15

    In this work a comprehensive study on a new active packaging obtained by a hybrid organic-inorganic coating with antimicrobial properties was carried out. The packaging system based on polylactic acid was realised by sol-gel processing, employing tetraethoxysilane as a precursor of the inorganic phase and polyvinyl alcohol as the organic component, and incorporating natamycin as the active agent. Films with different organic-inorganic ratios (in a range between 1:19 and 1:4) were prepared, and the amount of antimycotic entrapped was found to be modulated by the sol composition, and was between 0.18 and 0.25mg/dm(2). FTIR microspectroscopic measurements were used to characterise the prepared coatings. The antifungal properties of the films were investigated against mould growth on the surface of commercial semi-soft cheese. The release of natamycin from the films to ethanol 50% (v/v) was studied by means of HPLC UV-DAD. The maximal level released was about 0.105 mg/dm(2), which is far below the value allowed by legislation.

  12. Use of copolymer polylactic and polyglycolic acid resorbable plates in repair of orbital floor fractures.

    Science.gov (United States)

    Lin, Jonathan; German, Michael; Wong, Brian

    2014-10-01

    The fractures of the orbital floor are common after craniofacial trauma. Repair with resorbable plates is a viable reconstructive option; however, there are few reports in the literature. This study describes our experience using copolymer polylactic and polyglycolic acid (PLLA/PGA) orbital reconstruction plates (LactoSorb, Lorenz Surgical, Jacksonville, FL) in 29 cases of the orbital floor fracture repair. We conducted a retrospective review of 29 orbital floor fractures at a single institution repaired through transconjunctival, preseptal dissection using PLLA/PGA plates fashioned to repair the orbital floor defect. Associated fractures included zygomaticomaxillary, LeFort, and nasoethmoid fractures. There were six patients with complications. Four patients had transient diplopia with complete resolution of symptoms within 1 year. One patient had diplopia postoperatively, but was later lost to follow-up. Two patients have had persistent enophthalmos since 1 year. In each of these cases, the floor fracture was coincident with significant panfacial or neurotrauma. We did not encounter any adverse inflammatory reactions to the implant material itself. The study concluded that orbital floor fracture repair with resorbable plates is safe, relatively easy to perform, and in the majority of cases was effective without complications. In the presence of severe orbital trauma, more rigid implant materials may be appropriate.

  13. Preparation of Lung-Targeting, Emodin-Loaded Polylactic Acid Microspheres and Their Properties

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    Xiaohong Chen

    2014-04-01

    Full Text Available Emodin (1,3,8-trihydroxy-6-methylanthraquinone has been identified to have the potential to improve lung fibrosis and lung cancer. To avoid the liver and kidney toxicities and the fast metabolism of emodin, emodin-loaded polylactic acid microspheres (ED-PLA-MS were prepared and their characteristics were studied. ED-PLA-MS were prepared by the organic phase dispersion-solvent diffusion method. By applying an orthogonal design, our results indicated that the optimal formulation was 12 mg/mL PLA, 0.5% gelatin, and an organic phase:glycerol ratio of 1:20. Using the optimal experimental conditions, the drug loading and encapsulation efficiencies were (19.0 ± 1.8% and (62.2 ± 2.6%, respectively. The average particle size was 9.7 ± 0.7 μm. In vitro studies indicated that the ED-PLA-MS demonstrated a well-sustained release efficacy. The microspheres delivered emodin, primarily to the lungs of mice, upon intravenous injection. It was also detected by microscopy that partial lung inflammation was observed in lung tissues and no pathological changes were found in other tissues of the ED-PLA-MS-treated animals. These results suggested that ED-PLA-MS are of potential value in treating lung diseases in animals.

  14. Effects of Inorganic Fillers on the Thermal and Mechanical Properties of Poly(lactic acid

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    Xingxun Liu

    2014-01-01

    Full Text Available Addition of filler to polylactic acid (PLA may affect its crystallization behavior and mechanical properties. The effects of talc and hydroxyapatite (HA on the thermal and mechanical properties of two types of PLA (one amorphous and one semicrystalline have been investigated. The composites were prepared by melt blending followed by injection molding. The molecular weight, morphology, mechanical properties, and thermal properties have been characterized by gel permeation chromatography (GPC, scanning electron microscope (SEM, instron tensile tester, thermogravimetric analysis (TGA, differential scanning calorimetry (DSC, and dynamic mechanical analysis (DMA. It was found that the melting blending led to homogeneous distribution of the inorganic filler within the PLA matrix but decreased the molecular weight of PLA. Regarding the filler, addition of talc increased the crystallinity of PLA, but HA decreased the crystallinity of PLA. The tensile strength of the composites depended on the crystallinity of PLA and the interfacial properties between PLA and the filler, but both talc and HA filler increased the toughness of PLA.

  15. Analysis of Gas Permeability Characteristics of Poly(Lactic Acid/Poly(Butylene Succinate Nanocomposites

    Directory of Open Access Journals (Sweden)

    Amita Bhatia

    2012-01-01

    Full Text Available Gas permeability and morphological properties of nanocomposites prepared by the mixing of poly(lactic acid (PLA, poly(butylene succinate (PBS, and clay was investigated. While the composition of PLA and PBS polymers was fixed as 80% and 20% by weight, respectively, for all the nanocomposites, clay contents varied from 1 to 10 wt%. From the morphological studies using both wide angle X-ray diffraction and transmission electron microscopy, the nanocomposite having 1 wt% of clay was considered to have a mixed morphology of intercalated and delaminated structure, while some clusters or agglomerated particles were detected for nanocomposites having 3 and more than 3 wt% of clay content. However, the average particle size of the dispersed PBS phase was reduced significantly from 7 μm to 30–40 nm with the addition of clay in the blend. The oxygen barrier property was improved significantly as compared to the water vapor. A model based on gas barrier property was used for the validation of the oxygen relative permeabilities of PLA/PBS/clay nanocomposites. PLA/PBS/clay nanocomposites validated the Bharadwaj model up to 3 wt% of clay contents only, while for nanocomposites of higher clay contents the Bharadwaj model was invalid due to the clusters and agglomerates formed.

  16. Review on Chlorobenzoic Acids Biodegradation and Their Environmental Impacts

    Institute of Scientific and Technical Information of China (English)

    LuWenming; QiYun; ZhaoLin; TanXin

    2005-01-01

    Chlorobenzoic Acids are toxic organic compounds largely distributed in soils and sediments. They can be degraded to various products by microorgans. This paper is a review of the literature on biodegradability of the chlorobenzoic acids. The degradation pathways, degradation genes, role of transposable elements, and construction of strains are discussed. A brief introduction is given on the environmental impacts and the pollution control.

  17. Study of the free volume fraction in polylactic acid (PLA) by thermal analysis

    Science.gov (United States)

    Abdallah, A.; Benrekaa, N.

    2015-10-01

    The poly (lactic acid) or polylactide (PLA) is a biodegradable polymer with high modulus, strength and thermoplastic properties. In this work, the evolution of various properties of PLA is studied, such as glass transition temperature, mechanical modules and elongation percentage with the aim of investigating the free volume fraction. To do so, two thermal techniques have been used: the dynamic mechanical analysis (DMA) and dilatometry. The results obtained by these techniques are combined to go back to the structural properties of the studied material.

  18. Solvent-free preparation of polylactic acid fibers by melt electrospinning using umbrella-like spray head and alleviation of problematic thermal degradation

    Directory of Open Access Journals (Sweden)

    Liu Yong

    2012-01-01

    Full Text Available Melt electrospinning is an even simpler and safer method compared with the solution electrospinning in the production of ultra-fine fibers. Polylactic acid (PLA is a biodegradable and resorbable aliphatic ester that has received significant attention in recent years. PLA is easily degradable at high temperature in the process of melt electrospinning. High efficient fibers were made using our designed umbrella-like spray head spinning facility in this work. To find how to alleviate the problematic degradation and what factors could be relevant to degradation, temperature, relative molecular mass, Differential Scanning Calorimeter and X-ray Diffraction patterns before and after spinning were investigated and compared with each other. Results showed that fibers were facile shorten and fractured when spun at 245°C while the relative molecular mass of PLA fibers decreased markedly as compared with that spun at 210°C. To hinder the degradation, couple of experimental efforts were implemented with adding antioxidants, raising spinning voltage, lowering temperature, and reducing residence time. After such efforts, it was observed that the relative molecular mass of the PLA fibers was higher than those without inputting any efforts. The effect of antioxidant 1010 was found the most promising on the alleviation of PLA problematic thermal degradation.

  19. The effect of maleinized linseed oil (MLO) on mechanical performance of poly(lactic acid)-thermoplastic starch (PLA-TPS) blends.

    Science.gov (United States)

    Ferri, J M; Garcia-Garcia, D; Sánchez-Nacher, L; Fenollar, O; Balart, R

    2016-08-20

    In this work, poly(lactic acid), PLA and thermoplastic starch, TPS blends (with a fixed content of 30wt.% TPS) were prepared by melt extrusion process to increase the low ductile properties of PLA. The TPS used contains an aliphatic/aromatic biodegradable polyester (AAPE) that provides good resistance to aging and moisture. This blend provides slightly improved ductile properties with an increase in elongation at break of 21.5% but phase separation is observed due to the lack of strong interactions between the two polymers. Small amounts of maleinized linseed oil (MLO) can positively contribute to improve the ductile properties of these blends by a combined plasticizing-compatibilizing effect. The elongation at break increases over 160% with the only addition of 6phr MLO. One of the evidence of the plasticizing-compatibilizing effect provided by MLO is the change in the glass transition temperature (Tg) with a decrease of about 10°C. Field emission scanning electron microscopy (FESEM) of PLA-TPS blends with varying amounts of maleinized linseed oil also suggests an increase in compatibility. PMID:27178909

  20. Effect of twist-orientation on mechanical properties of self-reinforced poly(lactic acid) screws in simulated body environment

    Science.gov (United States)

    Sakaguchi, Masato; Kobayashi, Satoshi; composite engineering lab Team

    Poly(lactic acid) (PLA) attracts much attention as a typical biodegradable polymer, and has been applied as a bone fixation device. As one of the methods to improve mechanical properties of PLA bone fixation device, orientations of molecular chains have been investigated. However, conventional uniaxial drawing could not improve mechanical properties along the other loading direction than the drawing direction, such as torsion. In this study, screw is treated as a bone fixation device. In order to improve torsional strength of a bioabsorbable PLA screw, twist-orientation method has been developed. PLA screw is prepared through a series of routes including extrusion molding, extrusion drawing, twist-orientation and forging. This screw was immersed in the phosphate buffer solution for 0, 8, 16 and 24 weeks, then shear strength, orientation function, crystallinity and molecular weight were measured. As a result, twist-orientation improves the initial torsional strength of PLA screw without the decrease in initial shear strength. In addition, the shear strength on twist-oriented screw is equivalent that of non-twist oriented screw during immersion until 24 weeks. This result shown that the twist-orientation does not decrease shear strength after immersion.

  1. Evaluations of therapeutic efficacy of intravitreal injected polylactic-glycolic acid microspheres loaded with triamcinolone acetonide on a rabbit model of uveitis.

    Science.gov (United States)

    Li, Wenchang; He, Bing; Dai, Wenbing; Zhang, Qiang; Liu, Yuling

    2014-06-01

    Conventional treatments of uveitis are not ideal because of the short period of therapeutic efficacy. In the present study, biodegradable polylactic-glycolic acid microspheres loaded with triamcinolone acetonide (TA) were prepared to achieve sustained drug release and their therapeutic efficacy was investigated on a rabbit model of uveitis. TA-loaded microspheres (TA-MS) were prepared by the solvent evaporation method and characterized for encapsulation efficiency, particle size, morphology and in vitro release. The therapeutic efficacy was studied on the rabbit experimental uveitis model based on scoring of the inflammation, aqueous leukocyte counting, aqueous protein determination and histological examination. The TA-MS exhibited smooth and intact surfaces with an average diameter of 50.87 μm. The drug-loading coefficient and encapsulation efficiency were 15.2 ± 0.6 % and 91.24 ± 3.77 %, respectively. The drug release from TA-MS lasted up to 87 days, but only 46 days for TA suspension. The change in surface morphology also showed sustained drug release from TA-MS. TA-MS exhibited improved therapeutic efficacy in lipopolysaccharide -induced uveitis compared to TA suspension, especially in regard to the inhibition of inflammation. The TA-MS had a longer-term therapeutic effect on intraocular inflammation in LPS-induced uveitis in rabbits compared to TA suspension. The results suggested that TA-MS can be developed as a potential sustained-release system for the treatment of uveitis.

  2. Based on Modified Polylactic Acid Processing Methods%聚乳酸改性及成型加工研究进展

    Institute of Scientific and Technical Information of China (English)

    冯刚; 赵加伟

    2012-01-01

    Several kinds of modified methods was put forward based on shortcomings of polylactic acid, and two commonly used molding methods of polylactic acid were introduced, such as extrusion and injection molding.Finally the application of poly lactic acid was prospected.%针对生物可降解材料聚乳酸的一些缺点,提出了几种改性的方法,并对聚乳酸成型加工常用的两种方法,即挤出成型和注射成型做了介绍,最后对聚乳酸的应用进行了展望.

  3. Evaluation of biocompatibility and toxicity of biodegradable poly (DL-lactic acid) films.

    Science.gov (United States)

    Li, Rui-Yun; Liu, Zhi-Gang; Liu, Huan-Qiu; Chen, Lei; Liu, Jian-Feng; Pan, Yue-Hai

    2015-01-01

    Regeneration and functional recovery of nerves after peripheral nerve injury is the key to peripheral nerve repair. One of the putative therapeutic strategies is to use anti-adhesion polymer films, made of polymeric biomaterials. Recently, a novel biodegradable poly (DL-lactic acid) (PDLLA) film has been prepared using a method of phase transformation with biodegradable polylactic acid polymer as the substrate. This novel, anti-adhesion film has a porous structure, which provides better mechanical properties, better flexibility, more complete diffusion through the polymer of tissue biologic factors like growth factors, and more controllable degradation compared to traditional non-porous films. Little is known, however, about the in vitro and in vivo biocompatibility and cytotoxicity of this type of PDLLA film. Therefore, our aim was to evaluate the biocompatibility and cytotoxicity of this novel PDLLA film using various experimental methods, including a skin irritation test, MTT analysis, and the mouse bone marrow cell micronucleus test, as well as hematology or clinical chemistry measurements in rats after receiving sciatic nerve transection and anastomosis with wrapping of the anastomosis with DLLA films. We demonstrated that exposure to PDLLA film extracts did not generate apparent erythema or edema in rabbit skin and had no effect on the proliferation of Vero cells. Additionally, treatment with PDLLA film extracts did not alter the incidence of micronucleated polychromatic erythrocytes as compared with saline Treated group. Furthermore, implantation of PDLLA film did not alter liver or renal function as measured by serum levels of ALT, AST, TP, A/G, Cr, and BUN, and pathologic examinations showed that implantation of PDLLA film did not cause pathologic changes to the rat liver, kidney, pancreas, or spleen. Taken together, these results suggest that PDLLA films have excellent biocompatibility and no obvious toxicity in vivo, and may be used to prevent nerve

  4. Exploring the effect of cellulose nanowhiskers isolated from oil palm biomass on polylactic acid properties.

    Science.gov (United States)

    Haafiz, M K Mohamad; Hassan, Azman; Khalil, H P S Abdul; Fazita, M R Nurul; Islam, Md Saiful; Inuwa, I M; Marliana, M M; Hussin, M Hazwan

    2016-04-01

    In this work, polylactic acid (PLA) reinforced cellulose nanowhiskers (CNW) were prepared through solution casting technique. The CNW was first isolated from oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC) by using 64% H2SO4 and was designated as CNW-S. The optical microscopy revealed that the large particle of OPEFB-MCC has been broken down by the hydrolysis treatment. The atomic force microscopy confirmed that the CNW-S obtained is in nanoscale dimension and appeared in individual rod-like character. The produced CNW-S was then incorporated with PLA at 1, 3, and 5 parts per hundred (phr) resins for the PLA-CNW-S nanocomposite production. The synthesized nanocomposites were then characterized by a mean of tensile properties and thermal stability. Interestingly to note that incorporating of 3 phr/CNW-S in PLA improved the tensile strength by 61%. Also, CNW-S loading showed a positive impact on the Young's modulus of PLA. The elongation at break (Eb) of nanocomposites, however, decreased with the addition of CNW-S. Field emission scanning electron microscopy and transmission electron microscopy revealed that the CNW-S dispersed well in PLA at lower filler loading before it started to agglomerate at higher CNW-S loading (5phr). The DSC analysis of the nanocomposites obtained showed that Tg,Tcc and Tm values of PLA were improved with CNW-S loading. The TGA analysis however, revealed that incopreated CNW-S in PLA effect the thermal stability (T10,T50 and Tmax) of nanocomposite, where it decrease linearly with CNW-S loading. PMID:26772914

  5. Poly(lactic acid)/TiO{sub 2} nanocomposites as alternative biocidal and antifungal materials

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Carmen; Ochoa, Almudena [POLCA, Departamento de Ingeniería Mecánica, Química y Diseño Industrial, Escuela Técnica Superior de Ingeniería y Diseño Industrial, Universidad Politécnica de Madrid, Ronda de Valencia 3, Madrid (Spain); Ulloa, Maria Teresa; Alvarez, Eduardo [Programa de Microbiología y Micología. ICBM-Facultad de Medicina Universidad de Chile, Dirección, Avenida Independencia 1027, Comuna Independencia, Santiago (Chile); Canales, Daniel [Grupo Polímeros, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Casilla 40, Correo 33, Santiago (Chile); Zapata, Paula A., E-mail: paula.zapata@usach.cl [Grupo Polímeros, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Casilla 40, Correo 33, Santiago (Chile)

    2015-12-01

    Poly(lactic acid) (PLA) composites with titanium oxide (TiO{sub 2}) ~ 10-nm nanoparticles were produced by the melting process and their main properties were evaluated. The nanoparticles are homogeneously dispersed in the matrix with a low degree of agglomeration, as seen by transmission electron microscopy (TEM). The crystallinity temperature increased ~ 12% when 5 wt.% of TiO{sub 2} was added, showing that the nanoparticles acted as nucleating agents this trend was confirmed by optical images. The elastic modulus increased ~ 54% compared to neat PLA at 5 wt.% of nanoparticles. Despite these improvements, PLA/TiO{sub 2} nanocomposites showed lower shear viscosity than neat PLA, possibly reflecting degradation of the polymer due to the particles. Regarding biocidal properties, after 2 h of contact the PLA/TiO{sub 2} composites with 8 wt.% TiO{sub 2} showed a reduction of Escherichia coli colonies of ~ 82% under no UVA irradiation compared to pure PLA. This biocidal characteristic can be increased under UVA irradiation, with nanocomposites containing 8 wt.% TiO{sub 2} killing 94% of the bacteria. The PLA/TiO{sub 2} nanocomposites with 8 wt.% were also 99.99% effective against Aspergillus fumigatus under the UVA irradiation. - Highlights: • PLA composites with titanium oxide (10 nm) were produced by the melting process. • The crystallinity temperature increased ~ 12% when 5 wt.% of TiO{sub 2} was added. • The elastic modulus increased ~ 54% compared to neat PLA. • The PLA/TiO{sub 2} composites showed a reduction of Escherichia coli colonies of 94%. • The PLA/TiO{sub 2} nanocomposites with 8 wt.% were also 99.99% effective against fungi.

  6. Properties of poly(lactic acid nanocomposites based on montmorillonite, sepiolite and zirconium phosphonate

    Directory of Open Access Journals (Sweden)

    K. Fukushima

    2012-11-01

    Full Text Available Poly(lactic acid (PLA based nanocomposites based on 5 wt.% of an organically modified montmorillonite (CLO, unmodified sepiolite (SEP and organically modified zirconium phosphonate (ZrP were obtained by melt blending. Wide angle X-ray scattering (WAXS and scanning electron microscopy (SEM analysis showed a different dispersion level depending on the type and functionalisation of nanoparticles. Differenctial scanning calorimetric (DSC analysis showed that PLA was able to crystallize on heating, and that the addition of ZrP could promote extent of PLA crystallization, whereas the presence of CLO and SEP did not significantly affect the crystallization on heating and melting behaviour of PLA matrix. Dynamic Mechanical Thermoanalysis (DMTA results showed that addition of all nanoparticles brought considerable improvements in E' of PLA, resulting in a remarkable increase of elastic properties for PLA nanocomposites. The melt viscosity and dynamic shear moduli (G',G" of PLA nanocomposites were also enhanced significantly by the presence of CLO and SEP, and attributed to the formation of a PLA/nanoparticle interconnected structure within the polymer matrix. The oxygen permeability of PLA did not significantly vary upon addition of SEP and ZrP nanoparticles. Only addition of CLO led to about 30% decrease compared to PLA permeability, due to the good clay dispersion and clay platelet-like morphology. The characteristic high transparency of PLA in the visible region was kept upon addition of the nanoparticles. Based on these achievements, a high potential of these PLA nanocomposites in sustainable packaging applications could be envisaged.

  7. Poly(lactic acid)/TiO2 nanocomposites as alternative biocidal and antifungal materials

    International Nuclear Information System (INIS)

    Poly(lactic acid) (PLA) composites with titanium oxide (TiO2) ~ 10-nm nanoparticles were produced by the melting process and their main properties were evaluated. The nanoparticles are homogeneously dispersed in the matrix with a low degree of agglomeration, as seen by transmission electron microscopy (TEM). The crystallinity temperature increased ~ 12% when 5 wt.% of TiO2 was added, showing that the nanoparticles acted as nucleating agents this trend was confirmed by optical images. The elastic modulus increased ~ 54% compared to neat PLA at 5 wt.% of nanoparticles. Despite these improvements, PLA/TiO2 nanocomposites showed lower shear viscosity than neat PLA, possibly reflecting degradation of the polymer due to the particles. Regarding biocidal properties, after 2 h of contact the PLA/TiO2 composites with 8 wt.% TiO2 showed a reduction of Escherichia coli colonies of ~ 82% under no UVA irradiation compared to pure PLA. This biocidal characteristic can be increased under UVA irradiation, with nanocomposites containing 8 wt.% TiO2 killing 94% of the bacteria. The PLA/TiO2 nanocomposites with 8 wt.% were also 99.99% effective against Aspergillus fumigatus under the UVA irradiation. - Highlights: • PLA composites with titanium oxide (10 nm) were produced by the melting process. • The crystallinity temperature increased ~ 12% when 5 wt.% of TiO2 was added. • The elastic modulus increased ~ 54% compared to neat PLA. • The PLA/TiO2 composites showed a reduction of Escherichia coli colonies of 94%. • The PLA/TiO2 nanocomposites with 8 wt.% were also 99.99% effective against fungi

  8. Polylactic acid trays for fresh-food packaging: A Carbon Footprint assessment.

    Science.gov (United States)

    Ingrao, Carlo; Tricase, Caterina; Cholewa-Wójcik, Agnieszka; Kawecka, Agnieszka; Rana, Roberto; Siracusa, Valentina

    2015-12-15

    This paper discusses application of Carbon Footprint (CF) for quantification of the 100-year Global Warming Potential (GWP100) associated with the life cycle of polylactic acid (PLA) trays for packaging of fresh foods. A comparison with polystyrene (PS)-based trays was done considering two different transport system scenarios for PLA-granule supply to the tray production firm: a transoceanic freight vessel and an intercontinental freight aircraft. Doing so enabled estimation of the influence of the transportation phase on the GHG-emission rate associated with the PLA-trays' life cycle. From the assessment, the GWP100 resulted to be mainly due to PLA-granulate production and to its transportation to the tray manufacturing facility. Also, the study documented that, depending upon the transport system considered, the CF associated with the life cycle of the PLA trays can worsen so much that the latter are no longer GHG-emission saving as they are expected to be compared to the PS ones. Therefore, based upon the findings of the study, it was possible for the authors to understand the importance and the need of accounting for the transport-related issues in the design of PLA-based products, thus preserving their environmental soundness compared to traditional petroleum-based products. In this context, the study could be used as the base to reconsider the merits of PLA usage for product manufacturing, especially when high distances are implied, as in this analysed case. So, the authors believe that new research and policy frameworks should be designed and implemented for both development and promotion of more globally sustainable options. PMID:26282773

  9. Exploratory study on the pyrolysis and PAH emissions of polylactic acid

    Science.gov (United States)

    Chien, Yi-Chi; Liang, Chenju; Yang, Shu-hua

    2011-01-01

    The emission factors for 16 U.S. EPA priority polycyclic aromatic hydrocarbons (PAHs) from the polylactic acid (PLA) pyrolysis and the decomposition mechanism were investigated in this study. The fragments and gas compositions using on-line thermogravimetry-mass spectrometry (TG-MS) were determined. A temperature series of 7 fragments was analyzed in helium, and was found to include: m/z = 16, which may represent methane; 28, which may be carbon monoxide; 44, which may be acetaldehyde; 56, which may be methylketene, 144, which may be oligomers of lactide. In addition, there are little amount of 100, and 200 which are oligomers of lactides observed in the pyrolysis of PLA. The pyrolysis of PLA is a non-radical, backbiting ester interchange reaction involving the OH chain ends. Depending on the size of the cyclic transition state, the product can be a lactide molecule, an oligomeric ring with more than two repeat units, methylketene, or acetaldehyde. Carbon monoxide and methane are contributions from the decomposition of acetaldehyde. Experimentally, not detected (n.d.)-40.47 μg of 16 PAH emissions were determined from per gram of PLA pyrolysis. The PAH profiles showed a predominance of naphthalene (58.9%), phenanthrene (12.5%), and fluoranthene (5.9%). The total PAH emissions for PLA pyrolysis is significantly lower than the values associated with PLA combustion. From the viewpoint of air pollution control, this result suggests that pyrolysis seems a better alternative than combustion for the disposal of waste PLA. Also, since pyrolysis is the first step for an incineration process, these results can provide important information on the control of PAHs formation for a commercialized incinerator.

  10. Bioplastic composite foam prepared from poly(lactic acid) and natural wood flour

    Science.gov (United States)

    Suwannakas, Pokkes; Petrchwattana, Nawadon; Covavisaruch, Sirijutaratana

    2016-03-01

    The major drawbacks of Poly(lactic acid) (PLA) bioplastic are its cost and brittleness. This study aims to reduce the cost by foaming PLA reinforced with wood flour. A series of PLA/ natural fiber (WF) composite was prepared by using WF of selected conifers up to 5 wt%; each composite formulation was then foamed using 2 wt% of Azodicarbonamide (ADC) as chemical foaming agent. ADC effectively reduced the density of PLA and the PLA/WF composite foam by about 45% to 0.64 g/cm3 from 1.24 g/cm3 of neat PLA and 1.26 g/cm3 of PLA/WF composites when 2 wt% ADC was applied. Mechanical behaviors in terms of compressive and impact properties were investigated. With the presence of WF, the compressive stress increased with the WF content due to the good interfacial adhesion between the PLA matrix and the WF. This was verified by microscopic observation, leading to efficient stress transfer at the interface between PLA matrix and the WF. The presence of WF raised the specific compressive modulus and strength of PLA/WF composites to around 0.94 GPa.cm3/g and 2.65 MPa.cm3/g but foaming the PLA or the PLA/WF composites led to a dramatic reduction of the compressive modulus to 0.2-0.4 GPa.cm3/g, implying that the PLA and the PLA/WF foams had become softened. This was evidently observed in the significant reduction of hardness coupled with the vast drop of stress required to compressively deform the foams.

  11. Polylactic acid trays for fresh-food packaging: A Carbon Footprint assessment.

    Science.gov (United States)

    Ingrao, Carlo; Tricase, Caterina; Cholewa-Wójcik, Agnieszka; Kawecka, Agnieszka; Rana, Roberto; Siracusa, Valentina

    2015-12-15

    This paper discusses application of Carbon Footprint (CF) for quantification of the 100-year Global Warming Potential (GWP100) associated with the life cycle of polylactic acid (PLA) trays for packaging of fresh foods. A comparison with polystyrene (PS)-based trays was done considering two different transport system scenarios for PLA-granule supply to the tray production firm: a transoceanic freight vessel and an intercontinental freight aircraft. Doing so enabled estimation of the influence of the transportation phase on the GHG-emission rate associated with the PLA-trays' life cycle. From the assessment, the GWP100 resulted to be mainly due to PLA-granulate production and to its transportation to the tray manufacturing facility. Also, the study documented that, depending upon the transport system considered, the CF associated with the life cycle of the PLA trays can worsen so much that the latter are no longer GHG-emission saving as they are expected to be compared to the PS ones. Therefore, based upon the findings of the study, it was possible for the authors to understand the importance and the need of accounting for the transport-related issues in the design of PLA-based products, thus preserving their environmental soundness compared to traditional petroleum-based products. In this context, the study could be used as the base to reconsider the merits of PLA usage for product manufacturing, especially when high distances are implied, as in this analysed case. So, the authors believe that new research and policy frameworks should be designed and implemented for both development and promotion of more globally sustainable options.

  12. Exploring the effect of cellulose nanowhiskers isolated from oil palm biomass on polylactic acid properties.

    Science.gov (United States)

    Haafiz, M K Mohamad; Hassan, Azman; Khalil, H P S Abdul; Fazita, M R Nurul; Islam, Md Saiful; Inuwa, I M; Marliana, M M; Hussin, M Hazwan

    2016-04-01

    In this work, polylactic acid (PLA) reinforced cellulose nanowhiskers (CNW) were prepared through solution casting technique. The CNW was first isolated from oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC) by using 64% H2SO4 and was designated as CNW-S. The optical microscopy revealed that the large particle of OPEFB-MCC has been broken down by the hydrolysis treatment. The atomic force microscopy confirmed that the CNW-S obtained is in nanoscale dimension and appeared in individual rod-like character. The produced CNW-S was then incorporated with PLA at 1, 3, and 5 parts per hundred (phr) resins for the PLA-CNW-S nanocomposite production. The synthesized nanocomposites were then characterized by a mean of tensile properties and thermal stability. Interestingly to note that incorporating of 3 phr/CNW-S in PLA improved the tensile strength by 61%. Also, CNW-S loading showed a positive impact on the Young's modulus of PLA. The elongation at break (Eb) of nanocomposites, however, decreased with the addition of CNW-S. Field emission scanning electron microscopy and transmission electron microscopy revealed that the CNW-S dispersed well in PLA at lower filler loading before it started to agglomerate at higher CNW-S loading (5phr). The DSC analysis of the nanocomposites obtained showed that Tg,Tcc and Tm values of PLA were improved with CNW-S loading. The TGA analysis however, revealed that incopreated CNW-S in PLA effect the thermal stability (T10,T50 and Tmax) of nanocomposite, where it decrease linearly with CNW-S loading.

  13. Poly(lactic) acid fibers loaded with mesoporous silica for potential applications in the active food packaging

    Science.gov (United States)

    Cacciotti, Ilaria; Nanni, Francesca

    2016-06-01

    Multifunctional fibrous systems based on poly(lactic) acid (PLA), mesoporous silica (SiO2) and ascorbic acid (AA) were produced by means of electrospinning technique, for potential applications in the active food packaging sector, as platform for the controlled release of antioxidant and/or antimicrobial agents with the additional filtering function. The ascorbic acid was physisorbed on the surface of mesoporous silica in order to stabilize it and to extend its antioxidant action. The influence of mesoporous silica and ascorbic acid on the microstructural and mechanical properties was investigated, revealing a revelant mechanical reinforcement in the case of fibers loaded only with SiO2 and a decrement in the case of SiO2 with physisorbed ascorbic acid, due to the worse interface between the fillers and the polymeric matrix.

  14. Production of Bamboo Fiber Reinforced Fibrillated Poly(Lactic Acid) (PLA) Material Obtained by a Papermaking Process

    Institute of Scientific and Technical Information of China (English)

    WANG Ruibin; YANG Rendang; YANG Fei

    2015-01-01

    A devised beating process was applied, which enabled the formation of slurry consisting of uniformly dispersed fibrillated polylactic acid (PLA) fibers with bamboo fiber, and the polymer material was obtained by a conventional papermaking process. Owing to the fast dewatering time, good repeatability and the facility to manufacture on a large scale, this process was used. It was revealed that the beaten PLA fiber was overall in machinery extrusion by the results of optical microscope and scanning electron microscope (SEM) observations. The improvement in the tensile index, burst index, tear index and other mechanical properties was considered as a key benefit as a result of adding bamboo fiber.

  15. Hybrid poly(lactic acid)/nanocellulose/nanoclay composites with synergistically enhanced barrier properties and improved thermomechanical resistance

    DEFF Research Database (Denmark)

    Trifol Guzman, Jon; Plackett, David; Sillard, Cecile;

    2016-01-01

    Poly(lactic acid) (PLA)‐based hybrid nanocomposites (PLA, nanoclay and nanocellulose) were prepared by reinforcing neat PLA with commercially available nanoclay (Cloisite C30B) and nanocellulose, in the form of either partially acetylated cellulose nanofibres (CNFs) or nanocrystalline cellulose....... Composites with 1 or 5 wt% of nanocellulose, in combination with 1, 3 and 5 wt% of nanoclay, were prepared, and their barrier properties were investigated. It was found that the combination of clay and nanocellulose clearly resulted in synergistic behaviour in terms of the oxygen transmission rate (OTR...

  16. Flash co-pyrolysis of biomass with polylactic acid. Part 1: Influence on bio-oil yield and heating value

    OpenAIRE

    Cornelissen, Tom; Yperman, Jan; REGGERS, Guy; Schreurs, Sonja; Carleer, Robert

    2008-01-01

    High amounts of water present in bio-oil are one of the major drawbacks for its utilisation as a fuel. One technology that shows the potential to satisfy the demand for bio-oil with a reduced water content is the flash co-pyrolysis of biomass with polylactic acid, PLA. The influence of PLA on the pyrolysis of willow is investigated with a semi-continuous home-built pyrolysis reactor. Flash co-pyrolysis of willow/PLA blends (10: 1, 3: 1, 1:1 and 1:2) show synergetic interaction. ...

  17. Effects of a chitosan membrane coated with polylactic and polyglycolic acid on bone regeneration in a rat calvarial defect

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ui-Won [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Song, Kun-Young [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Kim, Chang-Sung [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Lee, Yong-Keun [Department and Research Institute of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-750 (Korea, Republic of); Cho, Kyoo-Sung [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Kim, Chong-Kwan [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of); Choi, Seong-Ho [Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752l (Korea, Republic of)

    2007-09-15

    The purpose of this study was to evaluate the effects of a chitosan membrane coated with polylactic and polyglycolic acid (PLGA) on bone regeneration in a rat calvarial defect. Surgical implantation of chitosan membranes resulted in enhanced local bone formation at both 2 and 8 weeks. In conclusion, the chitosan membrane coated with PLGA had a significant potential to induce bone formation in the rat calvarial defect model. Within the selected PLGA dose range and observation intervals, there appeared to be no meaningful differences in bone formation.

  18. New Composition of Maleic-Anhydride-Grafted Poly(Lactic Acid)/Rice Husk with Methylenediphenyl Diisocyanate

    OpenAIRE

    Tsou, Chi-Hui; Hung, Wei-Song; Chin-San WU; Chen, Jui-Chin; Chi-Yuan HUANG; Chiu, Shih-Hsuan; Chih-Yuan TSOU; Yao, Wei-Hua; Shang-Ming LIN; Chih-Kuei CHU; Hu, Chien-Chieh; Kueir-Rarn LEE; Suen, Maw-Cherng

    2014-01-01

    Maleic-anhydride-grafted poly(lactic acid) (PLA-g-MAH) was prepared and blended with rice husk (RH). Methylenediphenyl diisocyanate (MDI) was used as the coupling agent for combining RH with PLA-g-MAH, which improved the poor interfacial adhesion between PLA and RH. Various PLA-g-MAH/RH blends, with and without MDI, were prepared by melt processing using a brabender. The effects that inclusion and distribution of MDI had on the mechanical properties and thermal behaviors of the composites wer...

  19. Thermal and mechanical properties of polylactic acid (PLA) and bagasse carboxymethyl cellulose (CMCB) composite by adding isosorbide diesters

    Science.gov (United States)

    Kamthai, Suthaphat; Magaraphan, Rathanawan

    2015-05-01

    An isosorbide diesters is one of isororbide types used as a plasticizer. The influence of this plasticizer on thermal and mechanical properties of polylactic acid and bagasse carboxymethyl cellulose (PLA/CMCB) composites was studied. PLA was blended with CMCB at 1%wt using various contents of isosorbide diesters (5, 10, 15 and 20%wt of PLA). The differential scanning calorimetric (DSC) and thermogravimetric (TGA) analyses indicated that the increment of isosorbide diesters concentration resulted in decreasing glass transition, melting and decomposition temperatures, as well as the reduction of storage modulus of PLA/CMCB composites. Moreover, the elongation of PLA/CMCB composites was significantly improved with increasing plasticizer content.

  20. Incorporation of preservatives in polylactic acid films for inactivating E. coli O157:H7 and extending microbiological shelf-life of strawberry puree

    Science.gov (United States)

    Antimicrobial films of polylactic acid polymer incorporated with nisin, Ethylenediaminetetraacetic acid (EDTA), sodium benzoate (SB), potassium sorbate (PS) and their combination were developed and their antimicrobial effects on the inactivation of Escherichia coli O157:H7 and natural background mic...

  1. [Anaerobic biodegradation of phthalic acid esters (Paes) in municipal sludge].

    Science.gov (United States)

    Liang, Zhi-Feng; Zhou, Wen; Lin, Qing-Qi; Yang, Xiu-Hong; Wang, Shi-Zhong; Cai, Xin-De; Qiu, Rong-Liang

    2014-04-01

    Phthalic acid esters (PAEs), a class of organic pollutants with potent endocrine-disrupting properties, are widely present in municipal sludge. Study of PAEs biodegradation under different anaerobic biological treatment processes of sludge is, therefore, essential for a safe use of sludge in agricultural practice. In this study, we selected two major sludge PAEs, i.e. di-n-butyl phthalate (DBP) and di-(2-enthylhexyl) phthalate (DEHP), to investigate their biodegradation behaviors in an anaerobic sludge digestion system and a fermentative hydrogen production system. The possible factors influencing PAEs biodegradation in relation to changes of sludge properties were also discussed. The results showed that the biodegradation of DBP reached 99.6% within 6 days, while that of DEHP was 46.1% during a 14-day incubation period in the anaerobic digestion system. By comparison, only 19.5% of DBP was degraded within 14 days in the fermentative hydrogen production system, while no degradation was detected for DEHP. The strong inhibition of the degradation of both PAEs in the fermentative hydrogen production system was ascribed to the decreases in microbial biomass and ratios of gram-positive bacteria/gram-negative bacteria and fungi/ bacteria, and the increase of concentrations of volatile fatty acids (e. g. acetic acid, propionic acid and butyric acid) during the fermentative hydrogen-producing process.

  2. Reduced Burst Release and Enhanced Oral Bioavailability in Shikimic Acid-Loaded Polylactic Acid Submicron Particles by Coaxial Electrospray.

    Science.gov (United States)

    Wang, Miaomiao; Wang, Yuanwen; Omari-Siaw, Emmanuel; Wang, Shengli; Zhu, Yuan; Xu, Ximing

    2016-08-01

    In this study, using the coaxial electrospray method, we prepared submicron particles of the water-soluble drug shikimic acid (SA) with polylactic acid (PLA) as a polymer, to reduce the burst release and enhance the oral bioavailability. In vitro release study performed in HCl solution (pH 1.2) showed that the coaxial electrospray submicron particles could reduce burst release effect and presented a sustained release profile, compared with free SA and the particles prepared by electrospray method. The absorption of SA in the intestinal tract, studied using an in situ perfusion method in rats, also revealed jejunum as the main absorptive segment followed by duodenum and ileum. Moreover, the SA-loaded particles greatly enhanced the absorption of SA in the tested intestinal segments. The intestinal absorption rate was not enhanced with increasing drug concentration (5-15 μg/mL) which suggested that active transport or facilitated diffusion could play vital role in SA absorption. In addition, the SA-loaded PLA coaxial electrospray particle exhibited a prolonged plasma circulation with enhanced bioavailability after oral administration. In all, the coaxial electrospray technique could provide notable advantages for the oral delivery of SA, thereby enhancing its clinical application.

  3. Composition dependence of the synergistic effect of nucleating agent and plasticizer in poly(lactic acid: A Mixture Design study

    Directory of Open Access Journals (Sweden)

    M. K. Fehri

    2016-04-01

    Full Text Available Blends consisting of commercial poly(lactic acid (PLA, poly(lactic acid oligomer (OLA8 as plasticizer and a sulfonic salt of a phthalic ester and poly(D-lactic acid as nucleating agents were prepared by melt extrusion, following a Mixture Design approach, in order to systematically study mechanical and thermal properties as a function of composition. The full investigation was carried out by differential scanning calorimetry (DSC, dynamic mechanical thermal analysis (DMTA and tensile tests. The crystallization half-time was also studied at 105 °C as a function of the blends composition. A range of compositions in which the plasticizer and the nucleation agent minimized the crystallization half-time in a synergistic way was clearly identified thanks to the application of the Mixture Design approach. The results allowed also the identification of a composition range to maximize the crystallinity developed during the rapid cooling below glass transition temperature in injection moulding, thus allowing an easier processing of PLA based materials. Moreover the mechanical properties were discussed by correlating them to the chemical structural features and thermal behaviour of blends.

  4. 聚乳酸解聚方法研究进展%Research Progress in Depolymerization of Polylactic Acid

    Institute of Scientific and Technical Information of China (English)

    张晓静; 杨学群; 刘仕伟; 刘福胜; 于世涛

    2012-01-01

    The research progresses in depolymerization of polylactic acid at home and abroad in recent years are reviewed. The depolymerization processes include pyrolysis, acidic hydrolysis, basic hydrolysis, neutral hydrolysis, high-temperature high-pressure hydrolysis, enzyme catalysis, methanol alcoholysis, n-butylalcohol alcoholysis, and so on. The feasibility of polylactic acid chemical depolymerization in ionic liquor environment is discussed and prospected.%综述了近年来国内外关于聚乳酸的热解聚法和酸性水解法、碱性水解法、中性水解法、高温高压水解法、酶催化法、甲醇醇解法、正丁醇醇解法等化学解聚法的研究进展,并对聚乳酸在离子液体环境中进行化学解聚的可行性进行了探讨和展望.

  5. Electrospun polycaprolactone/polylactic acid nanofibers as an artificial nerve conduit

    International Nuclear Information System (INIS)

    Development of conduits made of biodegradable nanofibers is gaining substantial interest due to their suitability for nerve regeneration. Among all polymeric nanofibers PCL (Poly-Caprolactone) is distinctively found for mechanical stability and PLLA (Poly (L-Lactic Acid)) for relatively faster biodegradability. The aim of this study is to investigate blending compatibility between PCL and PLLA and the ability to fabricate nanofibers conduits via electro spinning. The PCL-PLLA nano-fiber tubular made from different blend ratios of PCL-PLLA were electro spun. The electro spun nanofibers were continuously deposited over high speed rotating mandrel to fabricate nanofibers conduit having inner diameter of 2mm and the wall thickness of 55-65 m. The diameters of nano-fibers were between 715-860nm. FTIR (Fourier Transform Infrared) spectroscopy used to analyze chemical change in the blends of nerve conduits, which revealed that the PCL-PLLA blend nanofiber exhibit characteristic peaks of both PCL and PLLA and was composition dependent. The crystallinity of PCL-PLLA tubes were studied using WAXD (Wide Angle Xray Diffraction). The morphology of nanofibers were investigated under SEM (Scanning Electron Microscope). The mechanical properties of the conduits were also tested; the Young's modulus obtained for small diameter was 10MPa, twice as high as larger diameter. (author)

  6. Electrospun Polycaprolactone/Polylactic Acid Nanofibers as an Artificial Nerve Conduit

    Directory of Open Access Journals (Sweden)

    Zeeshan Ali Khatri

    2014-07-01

    Full Text Available Development of conduits made of biodegradable nanofibers is gaining substantial interest due to their suitability for nerve regeneration. Among all polymeric nanofibers PCL (Poly ?-Caprolactone is distinctively found for mechanical stability and PLLA (Poly (L-Lactic Acid for relatively faster biodegradability. The aim of this study is to investigate blending compatibility between PCL and PLLA and the ability to fabricate nanofibers conduits via electro spinning. The PCL-PLLA nano-fiber tubular made from different blend ratios of PCL-PLLA were electro spun. The electro spun nanofibers were continuously deposited over high speed rotating mandrel to fabricate nanofibers conduit having inner diameter of 2mm and the wall thickness of 55-65µm. The diameters of nano-fibers were between 715-860nm. FTIR (Fourier Transform Infrared spectroscopy used to analyze chemical change in the blends of nerve conduits, which revealed that the PCL-PLLA blend nanofiber exhibit characteristic peaks of both PCL and PLLA and was composition dependent. The crystallinity of PCL-PLLA tubes were studied using WAXD (Wide Angle Xray Diffraction. The morphology of nanofibers were investigated under SEM (Scanning Electron Microscope. The mechanical properties of the conduits were also tested; the Young?s modulus obtained for small diameter was 10MPa, twice as high as larger diameter.

  7. Thermoresponsive physical hydrogels of poly(lactic acid)/poly(ethylene glycol) stereoblock copolymers tuned by stereostructure and hydrophobic block sequence.

    Science.gov (United States)

    Mao, Hailiang; Shan, Guorong; Bao, Yongzhong; Wu, Zi Liang; Pan, Pengju

    2016-05-18

    CBABC-type poly(lactic acid) (PLA)/poly(ethylene glycol) (PEG) pentablock copolymers composed of a central PEG block (A) and enantiomeric poly(l-lactic acid) (PLLA, B), poly(d-lactic acid) (PDLA, C) blocks were synthesized. Such pentablock copolymers form physical hydrogels at high concentrations in an aqueous solution, which stem from the aggregation and physical bridging of copolymer micelles. These gels are thermoresponsive and turn into sols upon heating. Physical gelation, gel-to-sol transition, crystalline state, microstructure, rheological behavior, biodegradation, and drug release behavior of PLA/PEG pentablock copolymers and their gels were investigated; they were also compared with PLA-PEG-PLA triblock copolymers containing the isotactic PLLA or atactic poly(d,l-lactide) (PDLLA) endblocks and PLLA-PEG-PLLA/PDLA-PEG-PDLA enantiomeric mixtures. PLA hydrophobic domains in pentablock copolymer gels changed from a homocrystalline to stereocomplexed structure as the PLLA/PDLA block length ratio approached 1/1. The gel of symmetric pentablock copolymer exhibited a wider gelation region, higher gel-to-sol transition temperature, higher hydrophobic domain crystallinity, larger intermicellar distance, higher storage modulus, and slower degradation and drug release rate compared to those of the asymmetric PLA/PEG pentablock copolymers or triblock copolymers. SAXS results indicated that the PLLA/PDLA blocks stereocomplexation in pentablock copolymers facilitated the intermicellar aggregation and bridging. Cylindrical ordered structures were observed in all the gels formed from the PLA/PEG pentablock and triblock copolymers. The stereocomplexation degree and intermicellar distance of the pentablock copolymer gels increased with heating. PMID:27121732

  8. Water Absorption of Jute/Polylactic Acid Composite Intended for an Interior Application and Comparison with Wood-Based Panels

    Science.gov (United States)

    Zandvliet, C.; Bandyopadhyay, N. R.; Ray, D.

    2014-04-01

    Jute/polylactic acid (PLA) composite is of special interest because it is entirely from renewable resources with high mechanical properties. Thus, it could be a more eco-friendly alternative to the conventional wood-based panels made of formaldehyde resin which is asserted to be carcinogenic. Yet the water affinity of the natural fibres and susceptibility of polylactic acid towards hydrolysis raise a question about the water resistance of such composites in service condition. In this work, the water absorption behaviour of jute/PLA composites, jute/maleated polypropylene was investigated with regard to interior applications following the standard test method in accordance to ISO 16983:2003 `Wood-based panels—determination of swelling in thickness after immersion in water' and compared to standard of wood-based panels. Untreated and treated jute/PLA composites exhibited a superior water resistance property compared to particleboard, MDF and hardboard and they are by far, below the minimum requirement of the ISO standard 16983.

  9. Enhanced stereocomplex formation of poly(L-lactic acid) and poly(D-lactic acid) in the presence of stereoblock poly(lactic acid).

    Science.gov (United States)

    Fukushima, Kazuki; Chang, Yoon-Hee; Kimura, Yoshiharu

    2007-06-01

    Stereoblock poly(lactic acid) (sb-PLA) is incorporated into a 1:1 polymer blend system of poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) that has a high molecular weight to study its addition effect on the stereocomplex (sc) formation of PLLA and PDLA. The ternary polymer blend films are first prepared by casting polymer solutions of sb-PLA, PLLA, and PDLA with different compositions. Upon increasing the content of sb-PLA in the blend films the sc crystallization is driven to a higher degree, while the formation of homo-chiral (hc) crystals is decreased. Lowering the molecular weight of the incorporated sb-PLA effectively increases the sc formation. Consequently, it is revealed that sb-PLA can work as a compatibilizer to improve the poor sc formation in the polymer blend of PLLA and PDLA. PMID:17541929

  10. Controlled release of linalool using nanofibrous membranes of poly(lactic acid) obtained by electrospinning and solution blow spinning: A comparative study

    Science.gov (United States)

    The controlled-release of natural plant oils such as linalool is of interest in therapeutics, cosmetics, and antimicrobial and larvicidal products. The present study reports the release characteristics of linalool encapsulated at three concentrations (10, 15 and 20 wt.%) in poly(lactic acid) nanofib...

  11. 聚乳酸纤维/氨纶弹力包芯纱的开发%Development of Polylactic Acid Fiber Spandex Core Spun Yarn

    Institute of Scientific and Technical Information of China (English)

    张瑞云; 郭建生

    2012-01-01

    文章探讨了聚乳酸纤维/氨纶弹力包芯纱的生产工艺,阐述了在环锭细纱机上纺制聚乳酸纤维/氨纶弹力包芯纱的方法及各生产工序的工艺要点,对影响聚乳酸纤维/氨纶弹力包芯纱的主要工艺参数进行了工艺试验,并通过正交试验确定了纱线捻度和氨纶丝预牵伸倍数的最优工艺配置,最终顺利纺制出了40.13tex(77dtex)聚乳酸纤维与氨纶弹力包芯纱,质量达到了较好水平。%Processing of polylactic acid fiber spandex core spun yarn was discussed. Spinning method and key technology in each process of spinning polylactic acid fiber spandex core spun yarn on ring spinning frame were introduced. The process tests have been done in main processing parameters which influence the polylactic acid fiber spandex core spun yarn. The best optimization of yarn twist and pre-drafting ratio of spandex were selected through orthogonal test. Finally, 40.13tex(77dtex)polylactic acid fiber spandex core spun yarn could be spun successfully, the yarn quality could reach better level.

  12. Application of polylactic acid coating with antimicrobials in reduction of Escherichia coli O157:H7 and Salmonella stanley on apples

    Science.gov (United States)

    Survival of Escherichia coli O157:H7 and Salmonella Stanley on apples as affected by application of an antimicrobial polylactic acid (PLA) coating were investigated. Golden Delicious apples were spot inoculated with E. coli O157:H7 or S. Stanley and spray coated with PLA/solvent solutions containing...

  13. Effect of l-lysine-assisted surface grafting for nano-hydroxyapatite on mechanical properties and in vitro bioactivity of poly(lactic acid-co-glycolic acid).

    Science.gov (United States)

    Liuyun, Jiang; Lixin, Jiang; Chengdong, Xiong; Lijuan, Xu; Ye, Li

    2016-01-01

    It is promising and challenging to study surface modification for nano-hydroxyapatite to improve the dispersion and enhance the mechanical properties and bioactivity of poly(lactic acid-co-glycolic acid). In this paper, we designed an effective new surface grafting with the assist of l-lysine for nano-hydroxyapatite, and the nano-hydroxyapatite surface grafted with the assist of l-lysine (g-nano-hydroxyapatite) was incorporated into poly(lactic acid-co-glycolic acid) to develop a series of g-nano-hydroxyapatite/poly(lactic acid-co-glycolic acid) nano-composites. The surface modification reaction for nano-hydroxyapatite, the mechanical properties, and in vitro human osteoblast-like cell (MG-63) response were characterized and investigated by Fourier transformation infrared, thermal gravimetric analysis, dispersion test, electromechanical universal tester, differential scanning calorimeter measurements, and in vitro cells culture experiment. The results showed that the grafting amount on the surface of nano-hydroxyapatite was enhanced with the increase of l-lysine, and the dispersion of nano-hydroxyapatite was improved more, so that it brought about better promotion crystallization and more excellent mechanical enhancement effect for poly(lactic acid-co-glycolic acid), comparing with the unmodified nano-hydroxyapatite. Moreover, the cells' attachment and proliferation results confirmed that the incorporation of the g-nano-hydroxyapatite into poly(lactic acid-co-glycolic acid) exhibited better biocompatibility than poly(lactic acid-co-glycolic acid). The above results indicated that the new surface grafting with the assist of l-lysine for nano-hydroxyapatite was an ideal novel surface modification method, which brought about better mechanical enhancement effect and in vitro bioactivity for poly(lactic acid-co-glycolic acid) with adding higher g-nano-hydroxyapatite content, suggesting it had a great potential to be used as bone fracture internal fixation materials

  14. One-pot synthesis of macro-mesoporous bioactive glasses/polylactic acid for bone tissue engineering.

    Science.gov (United States)

    Han, Xiao; Wang, Dan; Chen, Xiang; Lin, Huiming; Qu, Fengyu

    2014-10-01

    The macro-mesoporous bioactive glasses/polylactic acid nanofibers were synthesized via electrospun method followed by acid treatment processing. It was identified to be an effective and simple synthetic strategy to form the uniform nanofibers about 350 nm in size. The non-ionic triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (P123), was used as the template for mesoporous structure (5 nm) and the macroporous structure about 10 μm in size derived from the overlapping of the nanofibers. Furthermore, the surface hydrophilic-hydrophobic property can be adjusted by varying the amount of mesoporous bioglass precursor (MBG-p). With the outstanding structure characters and the suitable hydrophilic property, these nanofiber composites show controlled drug release and the fast hydroxyapatite (HAP) mineralization performance. Herein, the novel materials are expected to have potential application for bone tissue engineering.

  15. Physicochemical properties of poly(lactic acid-co-glycolic acid film modified via blending with poly(butyl acrylate-co-methyl methacrylate

    Directory of Open Access Journals (Sweden)

    Guoquan Zhu

    2013-01-01

    Full Text Available A series of poly(lactic acid-co-glycolic acid (PLGA/poly(butyl acrylate-co-methyl methacrylate (P(BA-co-MMA blend films with different P(BA-co-MMA mole contents were prepared by casting the polymer blend solution in chloroform. Surface morphologies of the PLGAP(BA-co-MMA blend films were studied by scanning electron microscopy (SEM. Thermal, mechanical, and chemical properties of PLGAP(BA-co-MMA blend films were investigated by differential scanning calorimeter (DSC, thermogravimetric analysis (TGA, tensile tests, and surface contact angle tests. The introduction of P(BA-co-MMA could modify the properties of PLGA films.

  16. 竹纤维/聚乳酸复合材料界面调控%Interface control of bamboo fibers/polylactic acid composites

    Institute of Scientific and Technical Information of China (English)

    李新功; 郑霞; 吴义强

    2012-01-01

    The interface of the bamboo fibers/polylactic acid was controlled by alkali(NaOH) treatment,isocyanate(MDI) treatment and NaOH+MDI treatment,respectively.The results show that the NaOH treatment could further refine bamboo fibers and increase specific surface area,realizing the physical control of bamboo fibers/polylactic acid composites interface;MDI treatment could realize the chemical control of bamboo fibers/polylactic acid composites interface.All of the three kinds of the interface control methods could improve the mechanical properties of bamboo fibers/polylactic acid composites,among which NaOH+MDI treatment has the best positive effects on the interface properties of the composites,the tensile strength and impact strength of the bamboofibers/polylactic acid composites with interface control are increased 36.9% and 36.5%,respectively.%分别采用碱(NaOH)处理、异氰酸酯(MDI)处理以及NaOH+MDI处理的界面调控方法对竹纤维/聚乳酸复合材料界面进行调控。结果表明,NaOH处理可以进一步细化竹纤维,增加比表面积,实现对竹纤维/聚乳酸复合材料界面的物理调控;MDI处理能够实现对复合材料界面的化学调控;三种界面调控方法均可以改善竹纤维/聚乳酸复合材料的力学性能,而NaOH+MDI界面调控效果最佳,调控处理后复合材料拉伸强度和冲击强度分别增加了36.9%和36.5%。

  17. Superparamagnetic iron oxide--loaded poly(lactic acid)-D-alpha-tocopherol polyethylene glycol 1000 succinate copolymer nanoparticles as MRI contrast agent.

    Science.gov (United States)

    Prashant, Chandrasekharan; Dipak, Maity; Yang, Chang-Tong; Chuang, Kai-Hsiang; Jun, Ding; Feng, Si-Shen

    2010-07-01

    We developed a strategy to formulate supraparamagnetic iron oxides (SPIOs) in nanoparticles (NPs) of biodegradable copolymer made up of poly(lactic acid) (PLA) and d-alpha-tocopherol polyethylene glycol 1000 succinate (TPGS) for medical imaging by magnetic resonance imaging (MRI) of high contrast and low side effects. The IOs-loaded PLA-TPGS NPs (IOs-PNPs) were prepared by the single emulsion method and the nanoprecipitation method. Effects of the process parameters such as the emulsifier concentration, IOs loading in the nanoparticles, and the solvent to non-solvent ratio on the IOs distribution within the polymeric matrix were investigated and the formulation was then optimized. The transmission electron microscopy (TEM) showed direct visual evidence for the well dispersed distribution of the IOs within the NPs. We further investigated the biocompatibility and cellular uptake of the IOs-PNPs in vitro with MCF-7 breast cancer cells and NIH-3T3 mouse fibroblast in close comparison with the commercial IOs imaging agent Resovist. MRI imaging was further carried out to investigate the biodistribution of the IOs formulated in the IOs-PNPs, especially in the liver to understand the liver clearance process, which was also made in close comparison with Resovist. We found that the PLA-TPGS NPs formulation at the clinically approved dose of 0.8 mg Fe/kg could be cleared within 24 h in comparison with several weeks for Resovist. Xenograft tumor model MRI confirmed the advantages of the IOs-PNPs formulation versus Resovist through the enhanced permeation and retention (EPR) effect of the tumor vasculature. PMID:20434210

  18. Hydrothermal in situ preparation of TiO2 particles onto poly(lactic acid) electrospun nanofibres

    Science.gov (United States)

    Gupta, Kamal K.; Mishra, Pradeep K.; Srivastava, Pradeep; Gangwar, Mayank; Nath, Gopal; Maiti, Pralay

    2013-01-01

    The novel poly(lactic acid) (PLA)/TiO2 hybrid nanofibres are produced via electrospinning technique. Hydrolysed titanium precursor has been electrosprayed simultaneously on the continuous electrospun PLA nanofibres surface. The adhered amorphous titania has been transformed into TiO2 particle through hydrothermal treatment for different times. The phase structure has been worked out using XRD, FTIR, XPS and Raman spectroscopy. The predominant phase is anatase with a small extent of brookite phase after the hydrothermal treatment. The size and location of TiO2 particle have been determined using SEM micrographs. The orderness of the PLA crystallites has been checked using XRD patterns before and after hydrothermal treatment. UV absorption capability of the titania coated nanofibres has been enhanced to a significant level. The antimicrobial activity of the hybrids has been verified using two different microorganisms (gram negative Escherichia coli and gram positive Staphylococcus aureus bacteria) and 70% reduction of antimicrobial activity has been reported.

  19. Effect of gas saturation conditions on the expansion ratio of microcellular poly(lactic acid/wood-flour composites

    Directory of Open Access Journals (Sweden)

    2010-10-01

    Full Text Available Poly(lactic acid or PLA and PLA/wood-flour composites were microcellular foamed with CO2 through a batch foaming process. Specifically, the gas saturation pressure and time varied during processing to produce PLA foams with a high expansion ratio. A ten fold expansion ratio resulted in microcellular foamed PLA over unfoamed counterpart. The foaming conditions associated with such a high expansion ratio involved a lower gas saturation pressure up to 2.76 MPa, which corresponds to a critical gas concentration of approximately 9.4%. Beyond this critical value, foam expansion decreased significantly. Investigations also studied the effect of incorporating wood flour on the foamability of the resulting PLA/wood-flour composites. The addition of wood flour into the PLA matrix significantly affected the expansion ratio of PLA/wood-flour composite foams.

  20. Effect of silanecoupling agent on properties of biocomposites based on poly(lactic acid)and durian rind cellulose

    Science.gov (United States)

    Penjumras, P.; AbdulRahman, R.; Talib, R. A.; Abdan, K.

    2016-07-01

    Durian rind cellulose reinforced poly(lactic acid) (PLA) biocomposites were prepared using Brabender internal mixer followed by hot compression molding technique. Cellulose was previously treated by 3-aminopropyltriethoxysilane for improving the compatibility with PLA matrix. The silane-grafting of cellulose was confirmed via Fourier transform infrared spectroscopy (FTIR) with the presence of Si-O-Si, Si-C, and Si-O-C bonds. The silane-treated cellulose was subsequently introduced into PLA matrix, and the effects of cellulose surface modification on mechanical, thermal and morphological properties, and water absorption of biocomposites were studied. It was found that silane-treated cellulose reinforced biocompositeshave superior mechanical properties compared with untreated cellulose reinforced biocomposites. The lowest crystallization temperature of silane-treated biocomposites was confirmed via Differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) investigation also showed that adhesion of cellulose and PLA matrix was improved by modification of cellulosesurfaceusing3-aminopropyltriethoxysilanewhich can result in less water absorption into biocomposites.

  1. Modification of polylactic acid surface using RF plasma discharge with sputter deposition of a hydroxyapatite target for increased biocompatibility

    Science.gov (United States)

    Tverdokhlebov, S. I.; Bolbasov, E. N.; Shesterikov, E. V.; Antonova, L. V.; Golovkin, A. S.; Matveeva, V. G.; Petlin, D. G.; Anissimov, Y. G.

    2015-02-01

    Surface modification of polylactic acid (PLLA) by plasma of radio-frequency magnetron discharge with hydroxyapatite target sputtering was investigated. Increased biocompatibility was demonstrated using studies with bone marrow multipotent mesenchymal stromal cells. Atomic force microscopy demonstrates that the plasma treatment modifies the surface morphology of PLLA to produce rougher surface. Infrared spectroscopy and X-ray diffraction revealed that changes in the surface morphology are caused by the processes of PLLA crystallization. Fluorescent X-ray spectroscopy showed that the plasma treatment also changes the chemical composition of PLLA, enriching it with ions of the sputtered target: calcium, phosphorus and oxygen. It is hypothesized that these surface modifications increase biocompatibility of PLLA without increasing toxicity.

  2. Bark polyflavonoids from Pinus radiata as functional building-blocks for polylactic acid (PLA-based green composites

    Directory of Open Access Journals (Sweden)

    D. E. Garcia

    2016-10-01

    Full Text Available Polylactic acid (PLA was melt-blended with Pinus radiata unmodified and modified (hydroxypropyled bark polyflavonoids in order to use such polyphenolic building-blocks as functional additives for envisaged applications. Rheological, morphological, molecular, thermal, and flexural properties were studied. Polyflavonoids improved blend processability in terms of short-time mixing. Furthermore, hydroxypropylated polyflavonoids improve miscibility in binary and ternary blends. Blend-composition affects crystallization-, melting-, and glass transition-temperature of PLA, as well as thermal resistance, and flexural properties of the blends. Polyflavonoids induced PLA-crystallization, and polymer-chain decomposition. Modified and unmodified bark polyflavonoids from radiata pine can be used successfully in PLA-based green composites beyond the food-packaging applications. The high compatibility between PLA and hydroxypropyled polyflavonoids highlights the potential of such phenolic derivatives for PLA-based material design.

  3. Poly(dopamine) coating of 3D printed poly(lactic acid) scaffolds for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Kao, Chia-Tze [School of Dentistry, Chung Shan Medical University, Taichung City, Taiwan (China); Department of Stomatology, Chung Shan Medical University Hospital, Taichung City, Taiwan (China); Lin, Chi-Chang [Department of Chemical and Materials Engineering, Tunghai University, Taichung City, Taiwan (China); Chen, Yi-Wen; Yeh, Chia-Hung [3D Printing Medical Research Center, China Medical University Hospital, Taichung City, Taiwan (China); Fang, Hsin-Yuan [3D Printing Medical Research Center, China Medical University Hospital, Taichung City, Taiwan (China); Department of Thoracic Surgery, China Medical University Hospital, Taichung City, Taiwan (China); School of Medicine, College of Medicine, College of Public Health, Taichung City, Taiwan (China); Shie, Ming-You, E-mail: eviltacasi@gmail.com [3D Printing Medical Research Center, China Medical University Hospital, Taichung City, Taiwan (China)

    2015-11-01

    3D printing is a versatile technique to generate large quantities of a wide variety of shapes and sizes of polymer. The aim of this study is to develop functionalized 3D printed poly(lactic acid) (PLA) scaffolds and use a mussel-inspired surface coating to regulate cell adhesion, proliferation and differentiation of human adipose-derived stem cells (hADSCs). We prepared PLA 3D scaffolds coated with polydopamine (PDA). The chemical composition and surface properties of PDA/PLA were characterized by XPS. PDA/PLA modulated hADSCs' responses in several ways. Firstly, adhesion and proliferation, and cell cycle of hADSCs cultured on PDA/PLA were significantly enhanced relative to those on PLA. In addition, the collagen I secreted from cells was increased and promoted cell attachment and cell cycle progression were depended on the PDA content. In osteogenesis assay, the ALP activity and osteocalcin of hADSCs cultured on PDA/PLA were significantly higher than seen in those cultured on pure PLA scaffolds. Moreover, hADSCs cultured on PDA/PLA showed up-regulation of the ang-1 and vWF proteins associated with angiogenic differentiation. Our results demonstrate that the bio-inspired coating synthetic PLA polymer can be used as a simple technique to render the surfaces of synthetic scaffolds active, thus enabling them to direct the specific responses of hADSCs. - Highlights: • A simple method of 3D printed poly(lactic acid) scaffold coated with PDA • Promoted proliferation of hADSCs on PDA/PLA scaffolds • Increased collagen I, cell cycle, and cell adhesion with a high PDA content • Up-regulation of angiogenic and osteogenic of hADSCs • A promising method for bioinspired surface modification on PLA using PDA.

  4. Development of lovastatin-loaded poly(lactic acid microspheres for sustained oral delivery: in vitro and ex vivo evaluation

    Directory of Open Access Journals (Sweden)

    Guan QG

    2015-02-01

    Full Text Available Qigang Guan,1 Wei Chen,2 Xianming Hu2 1Department of Cardiology, The First Affiliated Hospital of China Medical University, Shenyang, People’s Republic of China; 2Department of Pharmaceutical, Shenyang Institute of Pharmaceutical Industry, Shenyang, People’s Republic of China Background: A novel lovastatin (LVT-loaded poly(lactic acid microsphere suitable for oral administration was developed in this study, and in vitro and in vivo characteristics were evaluated. Methods: The designed microspheres were obtained by an improved emulsion-solvent evaporation method. The morphological examination, particle size, encapsulation ratio, drug loading, and in vitro release were characterized. Pharmacokinetics studies were used to show that microspheres possess more advantages than the conventional formulations. Results: By using the emulsion-solvent evaporation method, it was simple to prepare microspheres and easy to scale up production. The morphology of formed microspheres showed a spherical shape with a smooth surface, without any particle aggregation. Mean size of the microspheres was 2.65±0.69 µm; the encapsulation efficiency was 92.5%±3.6%, and drug loading was 16.7%±2.1%. In vitro release indicated that the LVT microspheres had a well-sustained release efficacy, and ex vivo studies showed that after LVT was loaded to microspheres, the area under the plasma concentration-time curve from zero to the last measurable plasma concentration point and the extrapolation to time infinity increased significantly, which represented 2.63-fold and 2.49-fold increases, respectively, compared to suspensions. The rate of ex vivo clearance was significantly reduced. Conclusion: This research proved that poly(lactic acid microspheres can significantly prolong the drug circulation time in vivo and can also significantly increase the relative bioavailability of the drug. Keywords: lovastatin, microspheres, PLA, in vitro release, pharmacokinetics 

  5. Poly(dopamine) coating of 3D printed poly(lactic acid) scaffolds for bone tissue engineering

    International Nuclear Information System (INIS)

    3D printing is a versatile technique to generate large quantities of a wide variety of shapes and sizes of polymer. The aim of this study is to develop functionalized 3D printed poly(lactic acid) (PLA) scaffolds and use a mussel-inspired surface coating to regulate cell adhesion, proliferation and differentiation of human adipose-derived stem cells (hADSCs). We prepared PLA 3D scaffolds coated with polydopamine (PDA). The chemical composition and surface properties of PDA/PLA were characterized by XPS. PDA/PLA modulated hADSCs' responses in several ways. Firstly, adhesion and proliferation, and cell cycle of hADSCs cultured on PDA/PLA were significantly enhanced relative to those on PLA. In addition, the collagen I secreted from cells was increased and promoted cell attachment and cell cycle progression were depended on the PDA content. In osteogenesis assay, the ALP activity and osteocalcin of hADSCs cultured on PDA/PLA were significantly higher than seen in those cultured on pure PLA scaffolds. Moreover, hADSCs cultured on PDA/PLA showed up-regulation of the ang-1 and vWF proteins associated with angiogenic differentiation. Our results demonstrate that the bio-inspired coating synthetic PLA polymer can be used as a simple technique to render the surfaces of synthetic scaffolds active, thus enabling them to direct the specific responses of hADSCs. - Highlights: • A simple method of 3D printed poly(lactic acid) scaffold coated with PDA • Promoted proliferation of hADSCs on PDA/PLA scaffolds • Increased collagen I, cell cycle, and cell adhesion with a high PDA content • Up-regulation of angiogenic and osteogenic of hADSCs • A promising method for bioinspired surface modification on PLA using PDA

  6. Biodegradable microcontainers as an oral drug delivery system for poorly soluble drugs

    DEFF Research Database (Denmark)

    Nielsen, Line Hagner; Nagstrup, Johan; Keller, Stephan Sylvest;

    2013-01-01

    PURPOSE: To fabricate microcontainers in biodegradable polylactic acid (PLLA) polymer films using hot embossing, and investigate the application of fabricated microcontainers as an oral drug delivery system for a poorly soluble drug. METHODS: For fabrication of the PLLA microcontainers, a film...

  7. Biodegradation of a surrogate naphthenic acid under denitrifying conditions.

    Science.gov (United States)

    Gunawan, Yetty; Nemati, Mehdi; Dalai, Ajay

    2014-03-15

    Extraction of bitumen from the shallow oil sands generates extremely large volumes of waters contaminated by naphthenic acid which pose severe environmental and ecological risks. Aerobic biodegradation of NA in properly designed bioreactors has been investigated in our earlier works. In the present work, anoxic biodegradation of trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA) coupled to denitrification was investigated as a potential ex situ approach for the treatment of oil sand process waters in bioreactors whereby excessive aeration cost could be eliminated, or as an in situ alternative for the treatment of these waters in anoxic stabilization ponds amended with nitrate. Using batch and continuous reactors (CSTR and biofilm), effects of NA concentration (100-750mgL(-1)), NA loading rate (up to 2607.9mgL(-1)h(-1)) and temperature (10-35°C) on biodegradation and denitrification processes were evaluated. In the batch system biodegradation of trans-4MCHCA coupled to denitrification occurred even at the highest concentration of 750mgL(-1). Consistent with the patterns reported for aerobic biodegradation, increase in initial concentration of NA led to higher biodegradation and denitrification rates and the optimum temperature was determined as 23-24°C. In the CSTR, NA removal and nitrate reduction rates passed through a maximum due to increases in NA loading rate. NA loading rate of 157.8mgL(-1)h(-1) at which maximum anoxic NA and nitrate removal rates (105.3mgL(-1)h(-1) and 144.5mgL(-1)h(-1), respectively) occurred was much higher than those reported for the aerobic alternative (NA loading and removal rates: 14.2 and 9.6mgL(-1)h(-1), respectively). In the anoxic biofilm reactor removal rates of NA and nitrate were dependent on NA loading rate in a linear fashion for the entire range of applied loading rates. The highest loading and removal rates for NA were 2607.9 and 2028.1mgL(-1)h(-1), respectively which were at least twofold higher than the values

  8. A review of material properties of biodegradable and bioresorbable polymers and devices for GTR and GBR applications.

    Science.gov (United States)

    Hutmacher, D; Hürzeler, M B; Schliephake, H

    1996-01-01

    Use of bioresorbable and biodegradable materials for guided tissue and guided bone regeneration is under intense investigation and is being tested in clinical trials. This study presents a basic overview of material properties of bioresorbable and biodegradable polymers and devices for guided tissue and guided bone regeneration treatment. Collagens and aliphatic polyesters, such as poly(glycolic acid), poly(lactic acid), and poly(epsilon-caprolactone), are discussed, as well as biocompatibility, mechanical properties, and sterilization. PMID:8908867

  9. Application of phenomenological analysis in fused deposition modeling system based on polylactic acid%唯象分析法在聚乳酸熔融沉积成型系统中的应用

    Institute of Scientific and Technical Information of China (English)

    潘鑫龙; 陈元枝; 姜文英

    2014-01-01

    针对可降解生物材料聚乳酸在熔融沉积成型中的成型精度问题,运用唯象分析法,结合聚乳酸的物理特性与快速成型技术,计算聚乳酸快速成型速度参数。采用近似线性加速控制优化算法,对复杂的根号运算作泰勒级数近似法处理,降低对处理器的要求和内存的占用。以PiBot为实验平台,验证了唯象分析计算和近似线性加速理论的正确性和有效性。%According to the polylactic acid biodegradable material applied to fused deposition modeling technology,the mold-ing accuracy problems are studied.The physical properties of polylactic acid with rapid prototyping technology are consid-ered by using the phenomenological analysis method.The speed parameters of the rapid prototyping technology based on PLA are calculated.To reducing the requirements for the processor and memory's occupancy,the complex root calculation is simplified by using the approximating linear ramp algorithms which adopt Taylor series approximation.The validity and ef-fectiveness of the phenomenological analysis calculation and the approximating linear ramp theory is validated by the experi-mental platform of PiBot.

  10. Biodegradability of poly(lactic-co-glycolic acid) after femtosecond laser irradiation

    OpenAIRE

    Akimichi Shibata; Shuhei Yada; Mitsuhiro Terakawa

    2016-01-01

    Biodegradation is a key property for biodegradable polymer-based tissue scaffolds because it can provide suitable space for cell growth as well as tailored sustainability depending on their role. Ultrashort pulsed lasers have been widely used for the precise processing of optically transparent materials, including biodegradable polymers. Here, we demonstrated the change in the biodegradation of a poly(lactic-co-glycolic acid) (PLGA) following irradiation with femtosecond laser pulses at diffe...

  11. Studies on Synthesis of Electrochemically Exfoliated Functionalized Graphene and Polylactic Acid/Ferric Phytate Functionalized Graphene Nanocomposites as New Fire Hazard Suppression Materials.

    Science.gov (United States)

    Feng, Xiaming; Wang, Xin; Cai, Wei; Qiu, Shuilai; Hu, Yuan; Liew, Kim Meow

    2016-09-28

    Practical application of functionalized graphene in polymeric nanocomposites is hampered by the lack of cost-effective and eco-friendly methods for its production. Here, we reported a facile and green electrochemical approach for preparing ferric phytate functionalized graphene (f-GNS) by simultaneously utilizing biobased phytic acid as electrolyte and modifier for the first time. Due to the presence of phytic acid, electrochemical exfoliation leads to low oxidized graphene sheets (a C/O ratio of 14.8) that are tens of micrometers large. Successful functionalization of graphene was confirmed by the appearance of phosphorus and iron peaks in the X-ray photoelectron spectrum. Further, high-performance polylactic acid/f-GNS nanocomposites are readily fabricated by a convenient masterbatch strategy. Notably, inclusion of well-dispersed f-GNS resulted in dramatic suppression on fire hazards of polylactic acid in terms of reduced peak heat-release rate (decreased by 40%), low CO yield, and formation of a high graphitized protective char layer. Moreover, obviously improvements in crystallization rate and thermal conductivities of polylactic acid nanocomposites were observed, highlighting its promising potential in practical application. This novel strategy toward the simultaneous exfoliation and functionalization for graphene demonstrates a simple yet very effective approach for fabricating graphene-based flame retardants. PMID:27588582

  12. Studies on Synthesis of Electrochemically Exfoliated Functionalized Graphene and Polylactic Acid/Ferric Phytate Functionalized Graphene Nanocomposites as New Fire Hazard Suppression Materials.

    Science.gov (United States)

    Feng, Xiaming; Wang, Xin; Cai, Wei; Qiu, Shuilai; Hu, Yuan; Liew, Kim Meow

    2016-09-28

    Practical application of functionalized graphene in polymeric nanocomposites is hampered by the lack of cost-effective and eco-friendly methods for its production. Here, we reported a facile and green electrochemical approach for preparing ferric phytate functionalized graphene (f-GNS) by simultaneously utilizing biobased phytic acid as electrolyte and modifier for the first time. Due to the presence of phytic acid, electrochemical exfoliation leads to low oxidized graphene sheets (a C/O ratio of 14.8) that are tens of micrometers large. Successful functionalization of graphene was confirmed by the appearance of phosphorus and iron peaks in the X-ray photoelectron spectrum. Further, high-performance polylactic acid/f-GNS nanocomposites are readily fabricated by a convenient masterbatch strategy. Notably, inclusion of well-dispersed f-GNS resulted in dramatic suppression on fire hazards of polylactic acid in terms of reduced peak heat-release rate (decreased by 40%), low CO yield, and formation of a high graphitized protective char layer. Moreover, obviously improvements in crystallization rate and thermal conductivities of polylactic acid nanocomposites were observed, highlighting its promising potential in practical application. This novel strategy toward the simultaneous exfoliation and functionalization for graphene demonstrates a simple yet very effective approach for fabricating graphene-based flame retardants.

  13. Biodegradability evaluation of polymers by ISO 14855-2.

    Science.gov (United States)

    Funabashi, Masahiro; Ninomiya, Fumi; Kunioka, Masao

    2009-10-01

    Biodegradabilities of polymers and their composites in a controlled compost were described. Polycaprolactone (PCL) and poly(lactic acid) (PLA) were employed as biodegradable polymers. Biodegradabilities of PCL and PLA samples in a controlled compost were measured using a Microbial Oxidative Degradation Analyzer (MODA) according to ISO 14855-2. Sample preparation method for biodegradation test according to ISO/DIS 10210 was also described. Effects of sizes and shapes of samples on biodegradability were studied. Reproducibility of biodegradation test of ISO 14855-2 by MODA was confirmed. Validity of sample preparation method for polymer pellets, polymer film, and polymer products of ISO/DIS 10210 for ISO 14855-2 was confirmed. PMID:20111676

  14. 聚乳酸-乙醇酸共聚物/羟基磷灰石复合支架修复喉软骨缺损%Polylactic acid-glycolic acid copolymer/hydroxyapatite composite scaffold repairs laryngeal cartilage defect

    Institute of Scientific and Technical Information of China (English)

    刘永刚; 周香桃

    2015-01-01

    BACKGROUND:The traditional repair methods for laryngeal cartilage defect are restricted by donor source, rejection, which are difficult to be popularized. OBJECTIVE:To investigate the effect of polylactic acid-glycolic acid copolymer/hydroxyapatite composite scaffold in repair of laryngeal cartilage defect. METHODS: A total of 20 Wistar rats were randomly divided into polylactic acid-glycolic acid copolymer/hydroxyapatite composite scaffold and polylactic acid-glycolic acid copolymer scaffold groups. Polylactic acid-glycolic acid copolymer/hydroxyapatite composite scaffold and polylactic acid-glycolic acid copolymer scaffold were respectively used for repair after the establishment of laryngeal cartilage defect models. RESULTS AND CONCLUSION: The laryngeal cartilage defect diameter of rats at 3, 5 and 7 days after modeling in the polylactic acid-glycolic acid copolymer/hydroxyapatite composite scaffold group was significantly smaler than that in the polylactic acid-glycolic acid copolymer scaffold group. The laryngeal cartilage defect of rats in the polylactic acid-glycolic acid copolymer/hydroxyapatite composite scaffold group was basicaly repaired and presented with a smooth surface, and there were no clear boundaries with surrounding tissues; however, the laryngeal cartilage defect of rats in the polylactic acid-glycolic acid copolymer scaffold group had indentations with a rough surface, and there were obvious boundaries with surrounding tissues. These results demonstrate that polylactic acid-glycolic acid copolymer/hydroxyapatite composite scaffold can promote the repair of laryngeal cartilage defect part, and its repair effect is more ideal.%背景:喉软骨缺损传统的修复方法受到供体来源、排斥反应等限制,因而难以推广。目的:观察聚乳酸-乙醇酸共聚物/羟基磷灰石复合支架修复喉软骨缺损的效果。方法:将20只Wistar 大鼠随机分为聚乳酸-乙醇酸共聚物/羟基磷灰石复合支架组和聚

  15. Enhancement of Mechanical and Dynamic Mechanical Properties of Hydrophilic Nanoclay Reinforced Polylactic Acid/Polycaprolactone/Oil Palm Mesocarp Fiber Hybrid Composites

    OpenAIRE

    Chern Chiet Eng; Nor Azowa Ibrahim; Norhazlin Zainuddin; Hidayah Ariffin; Wan Md Zin Wan Yunus; Yoon Yee Then

    2014-01-01

    In previous studies, the effect of the addition of 1 wt% hydrophilic nanoclay on polylactic acid (PLA)/polycaprolactone (PCL)/oil palm mesocarp fiber (OPMF) biocomposites was investigated by tensile properties, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The current studies focus on the effect of addition of 1 wt% hydrophilic nanoclay on mechanical (flexural and impact properties) and dynamic mechanical properties of composites. The composites were characterized ...

  16. 聚乳酸/剑麻复合材料流变性能表征%Characterization of rheological properties of polylactic acid/sisal fiber composites

    Institute of Scientific and Technical Information of China (English)

    冯彦洪; 李展洪; 瞿金平; 刘斌; 何和智; 伍巍

    2011-01-01

    Rheological properties of polylactic acid/sisal fiber composites with different sisal fiber mass fraction were evaluated by the method of torque rheometer rheological properties testing. The lengths and widths of sisal fibers in the composites and the molecular weights of polylactic acid, including the processed materials and unprocessed PLA were measured. The effect of sisal fiber mass fraction and rotor speed on the length of sisal fiber in the composites were analysed. The degradation status of polylactic acid was also analyzed. The results showed that the non-Newtonian index of composites presented a peak at the sisal fiber mass fraction about 10%, then decreased with further increasing mass fraction. In the composites, because of the forces that were applied on the rigid sisal fiber by rotor, polylactic acid melt and interaction among fibers, the sisal fibers were snipped and the length-diameter ratio decreased. In addition, polyactic acid degraded due to the effect of rotor speed and sisal fiber content. These factors affected the rheological properties of polylactic acid/sisal fiber composites.%利用转矩流变仪测量流变特性的方法,表征了不同剑麻纤维含量下,聚乳酸(PLA)/剑麻复合材料的流变性能,并测量实验后纤维的长度和宽度、PLA分子量,分析剑麻纤维含量和转速对复合材料体系中纤维长度的影响,以及PLA降解情况.结果表明,复合材料的非牛顿指数在纤维含量为10%左右出现峰值,并进一步随含量的增加而减小.复合体系中,刚性剑麻纤维受到来自于转子、聚合物和纤维之间的作用力,纤维被剪短,长径比减小;聚乳酸会受到转速和纤维含量的影响发生降解,这些因素都会影响PLA/剑麻复合材料的流变性能.

  17. Investigating the use of coupling agents to improve the interfacial properties between a resorbable phosphate glass and polylactic acid matrix.

    Science.gov (United States)

    Hasan, Muhammad Sami; Ahmed, Ifty; Parsons, Andrew J; Rudd, Chris D; Walker, Gavin S; Scotchford, Colin A

    2013-09-01

    Eight different chemicals were investigated as potential candidate coupling agents for phosphate glass fibre reinforced polylactic acid composites. Evidence of reaction of the coupling agents with phosphate glass and their effect on surface wettability and glass degradation were studied along with their principle role of improving the interface between glass reinforcement and polymer matrix. It was found that, with an optimal amount of coupling agent on the surface of the glass/polymer, interfacial shear strength improved by a factor of 5. Evidence of covalent bonding between agent and glass was found for three of the coupling agents investigated, namely: 3-aminopropyltriethoxysilane; etidronic acid and hexamethylene diisocyanate. These three coupling agents also improved the interfacial shear strength and increased the hydrophobicity of the glass surface. It is expected that this would provide an improvement in the macroscopic properties of full-scale composites fabricated from the same materials which may also help to retain these properties for the desired length of time by retarding the breakdown of the fibre/matrix interface within these composites.

  18. Preparation and characterization of poly(lactic acid)-grafted TiO{sub 2} nanoparticles with improved dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Luo Yanbing; Wang Xiuli; Xu Dayun [Center for Degradable and Flame-Retardant Polymeric Materials (ERCEPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, Sichuan University, 29 Wangjiang Road, Chengdu 610064 (China); Wang Yuzhong, E-mail: yzwang@scu.edu.cn [Center for Degradable and Flame-Retardant Polymeric Materials (ERCEPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, Sichuan University, 29 Wangjiang Road, Chengdu 610064 (China)

    2009-05-15

    Poly(lactic acid) (PLA)-grafted TiO{sub 2} particles were prepared by in situ melt polycondensation of lactic acid onto the surface of TiO{sub 2} nanoparticles. The resulting products were characterized by FTIR, XPS, TG-FTIR, XRD analysis and electron microscopy observation so as to have a better understanding of bonding between the graft polymer and nanoparticles. New characteristic peaks of Ti-carboxylic coordination bond, the changes in the relative intensities of the infrared absorption bands of graft polymer and the two decomposition stage of PLA-grafted TiO{sub 2} confirmed that PLA was grafted on the surface of TiO{sub 2} nanoparticles. By attachment of PLA, the PLA-grafted TiO{sub 2} samples exhibited much better dispersion and a slightly larger particle size than bare TiO{sub 2} particles. PLA-grafted TiO{sub 2} nanoparticles will find wide applications in biomedical and eco-friendly materials, especially as fillers in PLA matrix.

  19. Preparation and characterization of poly(lactic acid)-grafted TiO 2 nanoparticles with improved dispersions

    Science.gov (United States)

    Luo, Yan-Bing; Wang, Xiu-Li; Xu, Da-Yun; Wang, Yu-Zhong

    2009-05-01

    Poly(lactic acid) (PLA)-grafted TiO 2 particles were prepared by in situ melt polycondensation of lactic acid onto the surface of TiO 2 nanoparticles. The resulting products were characterized by FTIR, XPS, TG-FTIR, XRD analysis and electron microscopy observation so as to have a better understanding of bonding between the graft polymer and nanoparticles. New characteristic peaks of Ti-carboxylic coordination bond, the changes in the relative intensities of the infrared absorption bands of graft polymer and the two decomposition stage of PLA-grafted TiO 2 confirmed that PLA was grafted on the surface of TiO 2 nanoparticles. By attachment of PLA, the PLA-grafted TiO 2 samples exhibited much better dispersion and a slightly larger particle size than bare TiO 2 particles. PLA-grafted TiO 2 nanoparticles will find wide applications in biomedical and eco-friendly materials, especially as fillers in PLA matrix.

  20. Chemical Synthesis and Optical Properties of CdS Poly(Lactic Acid) Nanocomposites and Their Transparent Fluorescent Films

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cai-Feng [Nanjing University of Technology; Cheng, Yu-Peng [Nanjing University of Technology; Xie, He-Yi [Nanjing University of Technology; Chen, Li [Nanjing University of Technology; Hu, Michael Z. [ORNL; Chen, Su [Nanjing University of Technology

    2011-01-01

    This paper describes the chemical synthesis of cadmium sulfide (CdS) polymer nanocomposites by covalently grafting poly(lactic acid) (PLA) onto the surfaces of CdS nanocrystals (NCs). Synthesis of the nanocomposites involved two steps. Lactic acid (LA) capped CdS NCs were first prepared by reacting cadmium chloride (CdCl2) with sodium sulfide (Na2S) using LA as the organic ligand in H2O/N,N-dimethylformamide (DMF) solution. Next CdS PLA nanocomposites were formed by in situ ring-opening polymerization of lactide on the surface of modified CdS NCs. Transparent fluorescent films were then successfully prepared by blending as-prepared CdS PLA nanocomposites with high-molecular-weight PLA. The as-prepared CdS NCs and their nanocomposites were studied by transmission electron microscopic imaging, thermogravimetric analyses, and spectroscopic measurements (ultraviolet-visible absorption and photoluminescence). The spectroscopic studies revealed that the CdS polymer nanocomposites exhibited good optical properties in terms of their photoluminescence and transparency.

  1. Melt electrospinning of poly(lactic acid) and polycaprolactone microfibers by using a hand-operated Wimshurst generator

    Science.gov (United States)

    Qin, Chong-Chong; Duan, Xiao-Peng; Wang, Le; Zhang, Li-Hua; Yu, Miao; Dong, Rui-Hua; Yan, Xu; He, Hong-Wei; Long, Yun-Ze

    2015-10-01

    A conventional melt electrospinning setup usually needs a large, heavy high-voltage power supply and cannot work without a plug (electricity supply). In this article, we report a new melt electrospinning setup based on a small hand-operated Wimshurst generator, which can avoid electrical interference between the high-voltage spinning system and the heating system, and make the setup very portable and safe. Poly(lactic acid) (PLA) and polycaprolactone (PCL) fibers with diameters of 15-45 μm were fabricated successfully by using this apparatus. Experimental parameters such as the rotational speed of the generator handle (a half turn to two turns per second) and the spinning distance (2-14 cm) were investigated. In addition, PLA and PCL fibers were directly melt-electrospun onto a pork liver, and the temperature and adhesiveness of the deposited fibers were studied. The results indicate that the apparatus and melt-electrospun polymer microfibers may be used in dressing for wound healing.A conventional melt electrospinning setup usually needs a large, heavy high-voltage power supply and cannot work without a plug (electricity supply). In this article, we report a new melt electrospinning setup based on a small hand-operated Wimshurst generator, which can avoid electrical interference between the high-voltage spinning system and the heating system, and make the setup very portable and safe. Poly(lactic acid) (PLA) and polycaprolactone (PCL) fibers with diameters of 15-45 μm were fabricated successfully by using this apparatus. Experimental parameters such as the rotational speed of the generator handle (a half turn to two turns per second) and the spinning distance (2-14 cm) were investigated. In addition, PLA and PCL fibers were directly melt-electrospun onto a pork liver, and the temperature and adhesiveness of the deposited fibers were studied. The results indicate that the apparatus and melt-electrospun polymer microfibers may be used in dressing for wound healing

  2. 聚乳酸纤维的定性鉴别及性能测试%Qualitative identification and performance test of polylactic acid fiber

    Institute of Scientific and Technical Information of China (English)

    吉利梅

    2012-01-01

    采用燃烧法、显微镜观察法、熔点法、溶解法和红外吸收光谱法对聚乳酸纤维进行了试验研究,并与普通涤纶纤维进行了比较分析.结果表明:聚乳酸纤维离开火焰燃烧时有独特的透明蓝色火焰,并有熔液连续下滴,其残渣为极少量淡黄色胶状物;纵向形态呈现较深的横向沟槽,截面形态为近似圆形,有明显的孔洞和裂缝;熔点范围为171~178℃;在煮沸后的88%甲酸、65%~68%硝酸溶液中立即溶解;在1 300~1 470 cm-1和1 030~1 210 cm-1指纹区的峰位和峰的数目与涤纶纤维有较大的差异;其制品与涤纶纤维制品同样具有较好的挺括性、韧性和耐疲劳性;抱合力、残留卷曲率优于涤纶纤维,但平滑性、卷曲的恢复能力比涤纶纤维差.%Polylactic acid fiber was studied by combustion method,microscopic observation method,melting point method,dissolution method and infrared absorption spectroscopy,and compared with the com-mon polyester fiber. The results showed that: polylactic acid fiber had a unique transparent blue burning flame when it left the flame,and a molten liquid continuous dropped,the residues were a very small amount of pale yellow jelly. The longitudinal morphology of polylactic acid fiber presented deep transverse grooves,the cross sectional shape was approximately circular,and had apparent pores and cracks. The melting point range of polylactic acid fiber was 171~178 ℃,and the fiber dissolved in the boiled 88% formic acid and 65% ~68% of nitric acid immediately. The polylactic acid fiber had big difference from polyester fiber in peak position and the peak numbers at 1 300~1 470 cm-1 and 1 030~1 210 cm-1 fingerprint area. Polylactic acid fiber product had similar good shape stability,tenacity and fatigue endurance with polyester fiber,the hold force and the residual crimp percentage of polylactic acid fiber were better than polyester fiber,but the smoothness and crimp recovery

  3. Fabrication of novel poly(lactic acid)/amorphous magnesium phosphate bionanocomposite fibers for tissue engineering applications via electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Huan, E-mail: Huan.Zhou@Rockets.utoledo.edu [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Nabiyouni, Maryam [Department of Bioengineering, The University of Toledo, Toledo, OH (United States); Lin, Boren [Department of Biological Sciences, The University of Toledo, Toledo, OH (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Department of Surgery (Dentistry), The University of Toledo, Toledo, OH (United States)

    2013-05-01

    Fibrous bionanocomposites consisting of amorphous magnesium phosphate (AMP) nanospheres and polylactic acid (PLA) were fabricated by electrospinning. There are two important signatures of this paper. First, AMP, as an alternative to well-known calcium phosphate (CaP) materials, is added to PLA as the second phase. To the best of our knowledge, it is the first attempt to fabricate magnesium phosphate (MgP)/biopolymer composite. This is made possible by our previously reported research on the successful synthesis of AMP nanospheres via microwave processing. Second, the sustained release of magnesium and phosphate ions from PLA matrix can stimulate a series of cell responses. The structure of the composites and their bone-like apatite-forming abilities in simulated body fluid (SBF) were examined. Additionally, the effects on the proliferation and differentiation of preosteoblast cells were evaluated by performing in vitro cell culture and monitoring markers such as Osteocalcin (OCN), Osteopontin (OPN), Alkaline phosphatase (ALP) and Collagen type-I (Col I) using real-time polymerase chain reaction (PCR). For better dispersion of AMP in the fibers, a surfactant, 12-hydroxysteric acid (HSA), as previously reported in the literature, was used. However, HSA significantly inhibited the proliferation and differentiation of preosteoblast cells, indicating the potential risk in using HSA in the combination of AMP or MgP in tissue engineering applications. - Highlights: ► Amorphous magnesium phosphate (AMP) nanospheres was synthesized. ► AMP/poly lactic acid (PLA) matrix was fabricated via electrospinning. ► AMP was found to be beneficial to MC3T3 preosteoblast cells proliferation. ► Surfactant 12-hydroxysteric acid (HSA) was toxic to preosteoblast cells.

  4. Osteogenesis of human adipose-derived stem cells on hydroxyapatite-mineralized poly(lactic acid) nanofiber sheets

    International Nuclear Information System (INIS)

    Electrospun fiber sheets with various orientations (random, partially aligned, and aligned) and smooth and roughened casted membranes were prepared. Hydroxyapatite (HA) crystals were in situ formed on these material surfaces via immersion in 10 × simulated body fluid solution. The size and morphology of the resulting fibers were examined using scanning electron microscopy. The average diameter of the fibers ranged from 225 ± 25 to 1050 ± 150 nm depending on the electrospinning parameters. Biological experiment results show that human adipose-derived stem cells exhibit different adhesion and osteogenic differentiation on the three types of fiber. The cell proliferation and osteogenic differentiation were best on the aligned fibers. Similar results were found for phosphorylated focal adhesion kinase expression. Electrospun poly(lactic acid) aligned fibers mineralized with HA crystals provide a good environment for cell growth and osteogenic differentiation and thus have great potential in the tissue engineering field. - Highlights: • hADSCs show higher adhesion and proliferation on HA-precipitate electrospun fiber sheets than those of the control membranes. • HA-mineralized fiber groups greatly improve cell growth and increase FAK and p-FAK expressions. • HA-precipitate electrospun fiber sheets present higher ALP and OC activity through the study periods. • Electrospun PLA fiber mineralized with HA provides a good environment for cell growth and osteogenic differentiation. • A simple immersion of electrospun fibers in 10 × SBF are a potential matrix for bone tissue engineering

  5. In vitro and in vivo evaluation of a polylactic acid-bioactive glass composite for bone fixation devices.

    Science.gov (United States)

    Vergnol, Gwenaelle; Ginsac, Nathalie; Rivory, Pascaline; Meille, Sylvain; Chenal, Jean-Marc; Balvay, Sandra; Chevalier, Jérôme; Hartmann, Daniel J

    2016-01-01

    Poly(lactic acid) is nowadays among the most used bioabsorbable materials for medical devices. To promote bone growth on the material surface and increase the degradation rate of the polymer, research is currently focused on organic-inorganic composites by adding a bioactive mineral to the polymer matrix. The purpose of this study was to investigate the ability of a poly(L,DL-lactide)-Bioglass® (P(L,DL)LA-Bioglass(®) 45S5) composite to be used as a bone fixation device. In vitro cell viability testing of P(l,dl)LA based composites containing different amounts of Bioglass(®) 45S5 particles was investigated. According to the degradation rate of the P(L,DL)LA matrix and the cytocompatibility experiments, the composite with 30 wt % of Bioglass® particles seemed to be the best candidate for further investigation. To study its behavior after immersion in simulated physiological conditions, the degradation of the composite was analyzed by measuring its weight loss and mechanical properties and by proceeding with X-ray tomography. We demonstrated that the presence of the bioactive glass significantly accelerated the in vitro degradation of the polymer. A preliminary in vivo investigation on rabbits shows that the addition of 30 wt % of Bioglass(®) in the P(L,DL)LA matrix seems to trigger bone osseointegration especially during the first month of implantation. This composite has thus strong potential interest for health applications. PMID:25677798

  6. Novel Electrospun Polylactic Acid Nanocomposite Fiber Mats with Hybrid Graphene Oxide and Nanohydroxyapatite Reinforcements Having Enhanced Biocompatibility

    Directory of Open Access Journals (Sweden)

    Chen Liu

    2016-08-01

    Full Text Available Graphene oxide (GO and a nanohydroxyapatite rod (nHA of good biocompatibility were incorporated into polylactic acid (PLA through electrospinning to form nanocomposite fiber scaffolds for bone tissue engineering applications. The preparation, morphological, mechanical and thermal properties, as well as biocompatibility of electrospun PLA scaffolds reinforced with GO and/or nHA were investigated. Electron microscopic examination and image analysis showed that GO and nHA nanofillers refine the diameter of electrospun PLA fibers. Differential scanning calorimetric tests showed that nHA facilitates the crystallization process of PLA, thereby acting as a nucleating site for the PLA molecules. Tensile test results indicated that the tensile strength and elastic modulus of the electrospun PLA mat can be increased by adding 15 wt % nHA. The hybrid nanocomposite scaffold with 15 wt % nHA and 1 wt % GO fillers exhibited higher tensile strength amongst the specimens investigated. Furthermore, nHA and GO nanofillers enhanced the water uptake of PLA. Cell cultivation, 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT and alkaline phosphatase tests demonstrated that all of the nanocomposite scaffolds exhibit higher biocompatibility than the pure PLA mat, particularly for the scaffold with 15 wt % nHA and 1 wt % GO. Therefore, the novel electrospun PLA nanocomposite scaffold with 15 wt % nHA and 1 wt % GO possessing a high tensile strength and modulus, as well as excellent cell proliferation is a potential biomaterial for bone tissue engineering applications.

  7. Polypyrrole-coated electrospun poly(lactic acid) fibrous scaffold: effects of coating on electrical conductivity and neural cell growth.

    Science.gov (United States)

    Sudwilai, Thitima; Ng, Jun Jye; Boonkrai, Chatikorn; Israsena, Nipan; Chuangchote, Surawut; Supaphol, Pitt

    2014-01-01

    Neuronal activities play critical roles in both neurogenesis and neural regeneration. In that sense, electrically conductive and biocompatible biomaterial scaffolds can be applied in various applications of neural tissue engineering. In this study, we fabricated a novel biomaterial for neural tissue engineering applications by coating electrospun poly(lactic acid) (PLA) nanofibers with a conducting polymer, polypyrole (PPy), via admicellar polymerization. Optimal conditions for polymerization and preparation of PPy-coated electrospun PLA nanofibers were obtained by comparing results from scanning electron microscopy, X-ray photoelectron spectrometer, and surface conductivity tests. In vitro cell culture experiments showed that PPy-coated electrospun PLA fibrous scaffold is not toxic. The scaffold could support attachment and migration of neural progenitor cells. Neurons derived from progenitor exhibited long neurite outgrowth under electrical stimulation. Our study concluded that PPy-coated electrospun PLA fibers had a good biocompatibility with neural progenitor cells and may serve as a promising material for controlling progenitor cell behaviors and enhancing neural repair. PMID:24933469

  8. Poly(lactic acid) porous scaffold with calcium phosphate mineralized surface and bone marrow mesenchymal stem cell growth and differentiation

    International Nuclear Information System (INIS)

    This work aims to modify the surface of a poly(lactic acid) (PLA) porous scaffold with calcium phosphate (CaP) via a simple solution-based technique, and to evaluate the effects of this modification on the responses of rat bone marrow mesenchymal stem cells (rBMMSCs). Under appropriate modification conditions involving stepwise-treatments in the Ca-and-P supersaturated solution under gentle agitation, a thin, poorly crystallized CaP layer was deposited. The BMMSCs derived from adult rats were shown to adhere quite well to the CaP-coated scaffold, and to proliferate actively with culturing time, although some down-regulation was noted with regard to the unmodified PLA scaffold. The osteogenic differentiation of rBMMSCs was significantly higher on the CaP-modified scaffold than on the unmodified scaffold, as confirmed by alkaline phosphatase (ALP) activity. Moreover, the expression of genes associated with bone, including collagen type I, osteopontin and bone sialoprotein, was stimulated better on the CaP-modified PLA scaffold. Based on these results, the currently used CaP-treatment was deemed effective in stimulating the osteogenic development of rBMMSCs on the PLA-based scaffold, and the CaP-treated PLA scaffold may be useful for future bone tissue engineering.

  9. Flash co-pyrolysis of biomass with polylactic acid. Part 1: Influence on bio-oil yield and heating value

    Energy Technology Data Exchange (ETDEWEB)

    T. Cornelissen; J. Yperman; G. Reggers; S. Schreurs; R. Carleer [Hasselt University, Diepenbeek (Belgium). Laboratory of Applied Chemistry

    2008-06-15

    High amounts of water present in bio-oil are one of the major drawbacks for its utilisation as a fuel. One technology that shows the potential to satisfy the demand for bio-oil with a reduced water content is the flash co-pyrolysis of biomass with polylactic acid, PLA. The influence of PLA on the pyrolysis of willow is investigated with a semi-continuous home-built pyrolysis reactor. Flash co-pyrolysis of willow/PLA blends (10:1, 3:1, 1:1 and 1:2) show synergetic interaction. A higher bio-oil yield and a lower water content as a function of the willow/PLA ratios are obtained. Among the tested blends, the 1:2 willow/PLA blend shows the most pronounced synergy: a reduction in the production of pyrolytic water of almost 28%, accompanied by an increase of more than 37% in the production of water-free bio-oil. Additionally, PLA shows to have a positive influence on the energetic value of the bio-oil produced and on the resulting energy recuperation. 23 refs., 7 figs., 4 tabs.

  10. Effectiveness of trimethylopropane trimethacrylate for the electron-beam-irradiation-induced cross-linking of polylactic acid

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Hon-Meng [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Bee, Soo-Tueen, E-mail: beest@utar.edu.my [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Ratnam, C.T. [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Sin, Lee Tin; Phang, Yee-Yao; Tee, Tiam-Ting [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Rahmat, A.R. [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

    2014-01-15

    Highlights: • Investigation of trimethylopropane trimethacrylate (TMPTMA) on electron beam irradiated PLA. • Irradiated PLA blends were weakened by incorporation of high amount of TMPTMA. • TMPTMA interacts with polymer free radicals to build crosslinking network. -- Abstract: The purpose of this research was to investigate the effects of various loading levels of trimethylopropane trimethacrylate (TMPTMA) on the properties of polylactic acid (PLA) cross-linked via electron-beam irradiation. PLA was compounded with 3–5 wt.% of TMPTMA to induce cross-linking upon subjection to electron-beam irradiation doses of 25–250 kGy. The physical properties of the PLA samples were characterised by means of X-ray diffraction, gel fraction and scanning electron microscopy analyses on fractured surfaces after tensile tests. The presence of TMPTMA in PLA was found to effectively increase the crystallite size and gel fraction. However, higher loading levels of TMPTMA could compromise the properties of the PLA/TMPTMA samples, indicating that a larger amount of monomer free radicals might promote degradation within the substantially cross-linked amorphous phase. Irradiation-induced cross-linking in the samples could improve the cross-linking density while decreasing the elongation and interfering with the crystallisation. These effects are caused by the intensive irradiation-induced chain scission that is responsible for the deterioration of the mechanical and crystalline properties of the samples.

  11. Poly(dopamine) coating of 3D printed poly(lactic acid) scaffolds for bone tissue engineering.

    Science.gov (United States)

    Kao, Chia-Tze; Lin, Chi-Chang; Chen, Yi-Wen; Yeh, Chia-Hung; Fang, Hsin-Yuan; Shie, Ming-You

    2015-11-01

    3D printing is a versatile technique to generate large quantities of a wide variety of shapes and sizes of polymer. The aim of this study is to develop functionalized 3D printed poly(lactic acid) (PLA) scaffolds and use a mussel-inspired surface coating to regulate cell adhesion, proliferation and differentiation of human adipose-derived stem cells (hADSCs). We prepared PLA 3D scaffolds coated with polydopamine (PDA). The chemical composition and surface properties of PDA/PLA were characterized by XPS. PDA/PLA modulated hADSCs' responses in several ways. Firstly, adhesion and proliferation, and cell cycle of hADSCs cultured on PDA/PLA were significantly enhanced relative to those on PLA. In addition, the collagen I secreted from cells was increased and promoted cell attachment and cell cycle progression were depended on the PDA content. In osteogenesis assay, the ALP activity and osteocalcin of hADSCs cultured on PDA/PLA were significantly higher than seen in those cultured on pure PLA scaffolds. Moreover, hADSCs cultured on PDA/PLA showed up-regulation of the ang-1 and vWF proteins associated with angiogenic differentiation. Our results demonstrate that the bio-inspired coating synthetic PLA polymer can be used as a simple technique to render the surfaces of synthetic scaffolds active, thus enabling them to direct the specific responses of hADSCs.

  12. Characterization of Active Packaging Films Made from Poly(Lactic Acid)/Poly(Trimethylene Carbonate) Incorporated with Oregano Essential Oil.

    Science.gov (United States)

    Liu, Dong; Li, Hongli; Jiang, Lin; Chuan, Yongming; Yuan, Minglong; Chen, Haiyun

    2016-01-01

    Antimicromial and antioxidant bioactive films based on poly(lactic acid)/poly(trimenthylene carbonate) films incorporated with different concentrations of oregano essential oil (OEO) were prepared by solvent casting. The antimicrobial, antioxidant, physical, thermal, microstructural, and mechanical properties of the resulting films were examined. Scanning electron microscopy analysis revealed that the cross-section of films became rougher when OEO was incorporated into PLA/PTMC blends. Differential scanning calorimetry analysis indicated that crystallinity of PLA phase decreased by the addition of OEO, but this did not affect the thermal stability of the films. Water vapor permeability of films slightly increased with increasing concentration of OEO. However, active PLA/PTMC/OEO composite films showed adequate barrier properties for food packaging application. The antimicrobial and antioxidant capacities were significantly improved with the incorporation of OEO (p < 0.05). The results demonstrated that an optimal balance between the mechanical, barrier, thermal, antioxidant, and antimicrobial properties of the films was achieved by the incorporation of 9 wt % OEO into PLA/PTMC blends. PMID:27240336

  13. Protective colloids and polylactic acid co-affecting the polymorphic crystal forms and crystallinity of indomethacin encapsulated in microspheres.

    Science.gov (United States)

    Lin, S Y; Chen, K S; Teng, H H

    1999-01-01

    The co-effect of protective colloids and polylactic acid (PLA) on the polymorphic crystal forms and crystallinity of indomethacin (IMC) in IMC-loaded PLA microspheres was investigated with differential scanning calorimetry, infrared spectroscopy and x-ray diffractometry, to evaluate the polymorphic crystal forms and crystallinity of IMC encapsulated in PLA microspheres. The surfactant, sodium dodecyl sulphate (SDS), was also used as a dispersing agent. The results indicate that the polymorphism and crystallinity of IMC encapsulated in IMC-loaded PLA microspheres was dependent on the type of protective colloid and PLA used. The amorphous state and alpha-form of IMC were found in the IMC-loaded PLA microspheres prepared using polysaccharide (pectin or beta-cyclodextrin) as a protective colloid or SDS as a dispersing agent. However, the amorphous and methylene chloride solvate of IMC seemed to exist in the IMC-loaded PLA microspheres prepared with the proteins (gelatin or albumin), synthetic cellulose derivative (methyl cellulose or hydroxylpropyl methylcellulose) or the synthetic nonionic polymer (polyvinyl alcohol, polyvinyl pyrrolidone or biosoluble polymer) as a protective colloid. PLA was found to express a certain crystallinity in microspheres and not be affected by the protective colloids, but it played a more important role in influencing the crystallization of IMC during microencapsulation than the protective colloids. No interaction occurred in the physical mixture of IMC and PLA, nor in the IMC-loaded PLA microspheres.

  14. Effect of silver nanoparticles and cellulose nanocrystals on electrospun poly(lactic) acid mats: morphology, thermal properties and mechanical behavior.

    Science.gov (United States)

    Cacciotti, Ilaria; Fortunati, Elena; Puglia, Debora; Kenny, Josè Maria; Nanni, Francesca

    2014-03-15

    The fabrication of ternary fibrous mats based on poly(lactic) acid (PLA), cellulose nanocrystals (CNCs, both pristine (p-CNCs) and modified with a commercial surfactant (s-CNCs)) and silver (Ag) nanoparticles by electrospinning is reported. Amounts of 1 and 5 wt.% were selected for Ag and CNCs, respectively. Neat PLA and binary PLA/Ag, PLA/p-CNCs and PLA/s-CNCs were produced as references. The CNCs and Ag influence on the microstructural, thermal and mechanical properties was investigated. The Ag and/or p-CNCs addition did not remarkably affect fiber morphology and average size dimension (between (468 ± 111) and (551 ± 122)nm), whereas the s-CNCs presence led to the deposition of a honeycomb-like network on a underneath layer of randomly oriented fibers. The efficiency of the surfactant use in promoting the CNC dispersion was demonstrated. A slight enhancement (e.g. around 25%, in terms of strength) of the mechanical properties of p-CNCs loaded fibers, particularly for PLA/Ag/p-CNCs, was revealed, whereas mats with s-CNCs showed a decrement (e.g. around 35-45%, in terms of strength), mainly imputable to the delamination between the upper honeycomb-like layer and the lower conventional fibrous mat. PMID:24528696

  15. New Composition of Maleic-Anhydride-Grafted Poly(Lactic Acid/Rice Husk with Methylenediphenyl Diisocyanate

    Directory of Open Access Journals (Sweden)

    Chi-Hui TSOU

    2014-12-01

    Full Text Available Maleic-anhydride-grafted poly(lactic acid (PLA-g-MAH was prepared and blended with rice husk (RH. Methylenediphenyl diisocyanate (MDI was used as the coupling agent for combining RH with PLA-g-MAH, which improved the poor interfacial adhesion between PLA and RH. Various PLA-g-MAH/RH blends, with and without MDI, were prepared by melt processing using a brabender. The effects that inclusion and distribution of MDI had on the mechanical properties and thermal behaviors of the composites were examined. The results showed that the PLAXRHYMDI specimens had the optimum tensile properties compared with the PLAXRHY, PLA-g-MAHXRHY, and PLA-g-MAHXRHYMDI specimens. The new method of combining MDI and MAH through grafting was expected to be an excellent strategy for mitigating the low functionality of commercial PLA. Possible reasons accounting for the interesting results on tensile strength and thermal properties of the specimens are proposed. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6034

  16. Effect of immersion in simulated body environment on mechanical properties of twist-oriented poly(lactic acid) screws

    Science.gov (United States)

    Sakaguchi, Masato; Kobayashi, Satoshi; composite engineering lab Collaboration

    Poly(lactic acid) (PLA) has been applied to bone fixation devices, since it has high biocompatibility. In order to apply PLA device to a higher loaded part, mechanical properties of PLA have been improved by uniaxial drawing. However, mechanical properties along the other loading direction than the drawing direction such as torsion were not improved. Therefore, surgeon should be carefully conducted not to brake the reinforced PLA screw when tightening. In this study, screw is focused on as a bone fixation device. In order to improve torsional strength of a PLA screw, twist-orientation method was developed. PLA screw is prepared through a series of routes including casting, extrusion drawing, twist-orientation and forging. This screw was immersed in the phosphate buffered solution for 0, 8, 16 and 24 weeks, then shear strength, orientation function, crystallinity and molecular weight were measured. As a result, twist-orientation improves the initial torsional strength of PLA screw without the decrease in initial shear strength. In addition, the shear strength on twist-oriented screw is equivalent that of non-twist oriented screw during immersion until 24 weeks. This result shown that the twist-orientation does not decrease shear strength after immersion.

  17. Effects of hydroxyapatite and PDGF concentrations on osteoblast growth in a nanohydroxyapatite-polylactic acid composite for guided tissue regeneration.

    Science.gov (United States)

    Talal, Ahmed; McKay, I J; Tanner, K E; Hughes, Francis J

    2013-09-01

    The technique of guided tissue regeneration (GTR) has evolved over recent years in an attempt to achieve periodontal tissue regeneration by the use of a barrier membrane. However, there are significant limitations in the currently available membranes and overall outcomes may be limited. A degradable composite material was investigated as a potential GTR membrane material. Polylactic acid (PLA) and nanohydroxyapatite (nHA) composite was analysed, its bioactive potential and suitability as a carrier system for growth factors were assessed. The effect of nHA concentrations and the addition of platelet derived growth factor (PDGF) on osteoblast proliferation and differentiation was investigated. The bioactivity was dependent on the nHA concentration in the films, with more apatite deposited on films containing higher nHA content. Osteoblasts proliferated well on samples containing low nHA content and differentiated on films with higher nHA content. The composite films were able to deliver PDGF and cell proliferation increased on samples that were pre-absorbed with the growth factor. nHA-PLA composite films are able to deliver active PDGF. In addition the bioactivity and cell differentiation was higher on films containing more nHA. The use of a nHA-PLA composite material containing a high concentration of nHA may be a useful material for GTR membrane as it will not only act as a barrier, but may also be able to enhance bone regeneration by delivery of biologically active molecules.

  18. Response Surface Methodology for the Optimization of Preparation of Biocomposites Based on Poly(lactic acid and Durian Peel Cellulose

    Directory of Open Access Journals (Sweden)

    Patpen Penjumras

    2015-01-01

    Full Text Available Response surface methodology was used to optimize preparation of biocomposites based on poly(lactic acid and durian peel cellulose. The effects of cellulose loading, mixing temperature, and mixing time on tensile strength and impact strength were investigated. A central composite design was employed to determine the optimum preparation condition of the biocomposites to obtain the highest tensile strength and impact strength. A second-order polynomial model was developed for predicting the tensile strength and impact strength based on the composite design. It was found that composites were best fit by a quadratic regression model with high coefficient of determination (R2 value. The selected optimum condition was 35 wt.% cellulose loading at 165°C and 15 min of mixing, leading to a desirability of 94.6%. Under the optimum condition, the tensile strength and impact strength of the biocomposites were 46.207 MPa and 2.931 kJ/m2, respectively.

  19. Characterization of Active Packaging Films Made from Poly(Lactic Acid/Poly(Trimethylene Carbonate Incorporated with Oregano Essential Oil

    Directory of Open Access Journals (Sweden)

    Dong Liu

    2016-05-01

    Full Text Available Antimicromial and antioxidant bioactive films based on poly(lactic acid/poly(trimenthylene carbonate films incorporated with different concentrations of oregano essential oil (OEO were prepared by solvent casting. The antimicrobial, antioxidant, physical, thermal, microstructural, and mechanical properties of the resulting films were examined. Scanning electron microscopy analysis revealed that the cross-section of films became rougher when OEO was incorporated into PLA/PTMC blends. Differential scanning calorimetry analysis indicated that crystallinity of PLA phase decreased by the addition of OEO, but this did not affect the thermal stability of the films. Water vapor permeability of films slightly increased with increasing concentration of OEO. However, active PLA/PTMC/OEO composite films showed adequate barrier properties for food packaging application. The antimicrobial and antioxidant capacities were significantly improved with the incorporation of OEO (p < 0.05. The results demonstrated that an optimal balance between the mechanical, barrier, thermal, antioxidant, and antimicrobial properties of the films was achieved by the incorporation of 9 wt % OEO into PLA/PTMC blends.

  20. Modification of polylactic acid surface using RF plasma discharge with sputter deposition of a hydroxyapatite target for increased biocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Tverdokhlebov, S.I., E-mail: tverd@tpu.ru [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation); Bolbasov, E.N.; Shesterikov, E.V. [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation); Antonova, L.V.; Golovkin, A.S.; Matveeva, V.G. [Federal State Budgetary Institution Research Institute for Complex Issues of Cardiovascular Disease, 6 Sosnovy Blvd, Kemerovo 650002 (Russian Federation); Petlin, D.G.; Anissimov, Y.G. [Griffith University, School of Natural Sciences, Engineering Dr., Southport, QLD 4222 (Australia)

    2015-02-28

    Highlights: • The treatment by plasma of radio-frequency magnetron discharge with hydroxyapatite target sputtering improves the biocompatibility of PLLA surface. • The treatment significantly increases the roughness of PLLA surface. • The formation of rough highly porous surface is due to the etching and crystallization processes on PLLA surface during treatment. • Maximum concentration of the ions from the sputtered target is achieved at 60 s of the plasma treatment. - Abstract: Surface modification of polylactic acid (PLLA) by plasma of radio-frequency magnetron discharge with hydroxyapatite target sputtering was investigated. Increased biocompatibility was demonstrated using studies with bone marrow multipotent mesenchymal stromal cells. Atomic force microscopy demonstrates that the plasma treatment modifies the surface morphology of PLLA to produce rougher surface. Infrared spectroscopy and X-ray diffraction revealed that changes in the surface morphology are caused by the processes of PLLA crystallization. Fluorescent X-ray spectroscopy showed that the plasma treatment also changes the chemical composition of PLLA, enriching it with ions of the sputtered target: calcium, phosphorus and oxygen. It is hypothesized that these surface modifications increase biocompatibility of PLLA without increasing toxicity.

  1. Molecular surface area based predictive models for the adsorption and diffusion of disperse dyes in polylactic acid matrix.

    Science.gov (United States)

    Xu, Suxin; Chen, Jiangang; Wang, Bijia; Yang, Yiqi

    2015-11-15

    Two predictive models were presented for the adsorption affinities and diffusion coefficients of disperse dyes in polylactic acid matrix. Quantitative structure-sorption behavior relationship would not only provide insights into sorption process, but also enable rational engineering for desired properties. The thermodynamic and kinetic parameters for three disperse dyes were measured. The predictive model for adsorption affinity was based on two linear relationships derived by interpreting the experimental measurements with molecular structural parameters and compensation effect: ΔH° vs. dye size and ΔS° vs. ΔH°. Similarly, the predictive model for diffusion coefficient was based on two derived linear relationships: activation energy of diffusion vs. dye size and logarithm of pre-exponential factor vs. activation energy of diffusion. The only required parameters for both models are temperature and solvent accessible surface area of the dye molecule. These two predictive models were validated by testing the adsorption and diffusion properties of new disperse dyes. The models offer fairly good predictive ability. The linkage between structural parameter of disperse dyes and sorption behaviors might be generalized and extended to other similar polymer-penetrant systems.

  2. In vitro and in vivo evaluation of a polylactic acid-bioactive glass composite for bone fixation devices.

    Science.gov (United States)

    Vergnol, Gwenaelle; Ginsac, Nathalie; Rivory, Pascaline; Meille, Sylvain; Chenal, Jean-Marc; Balvay, Sandra; Chevalier, Jérôme; Hartmann, Daniel J

    2016-01-01

    Poly(lactic acid) is nowadays among the most used bioabsorbable materials for medical devices. To promote bone growth on the material surface and increase the degradation rate of the polymer, research is currently focused on organic-inorganic composites by adding a bioactive mineral to the polymer matrix. The purpose of this study was to investigate the ability of a poly(L,DL-lactide)-Bioglass® (P(L,DL)LA-Bioglass(®) 45S5) composite to be used as a bone fixation device. In vitro cell viability testing of P(l,dl)LA based composites containing different amounts of Bioglass(®) 45S5 particles was investigated. According to the degradation rate of the P(L,DL)LA matrix and the cytocompatibility experiments, the composite with 30 wt % of Bioglass® particles seemed to be the best candidate for further investigation. To study its behavior after immersion in simulated physiological conditions, the degradation of the composite was analyzed by measuring its weight loss and mechanical properties and by proceeding with X-ray tomography. We demonstrated that the presence of the bioactive glass significantly accelerated the in vitro degradation of the polymer. A preliminary in vivo investigation on rabbits shows that the addition of 30 wt % of Bioglass(®) in the P(L,DL)LA matrix seems to trigger bone osseointegration especially during the first month of implantation. This composite has thus strong potential interest for health applications.

  3. Improved wettability and adhesion of polylactic acid/chitosan coating for bio-based multilayer film development

    Science.gov (United States)

    Gartner, Hunter; Li, Yana; Almenar, Eva

    2015-03-01

    The objective of this study was to investigate the effect of methyldiphenyl diisocyanate (MDI) concentration (0, 0.2, 1, 2, and 3%) on the wettability and adhesion of blend solutions of poly(lactic acid) (PLA) and chitosan (CS) when coated on PLA film for development of a bio-based multi-layer film suitable for food packaging and other applications. Characterization was carried out by attenuated total reflectance infrared spectrometry (ATR-FTIR), contact angle (θ), mechanical adhesion pull-off testing, and scanning electron microscopy (SEM). The θ of the PLA/CS blend shifted to a lower value (41-35°) with increasing MDI concentration showing that the surface tension was modified between the PLA/CS blend solution and PLA film and better wettability was achieved. The increase in MDI also resulted in an increased breaking strength (228-303 kPa) due to the increased H-bonding resulting from the more urethane groups formed within the PLA/CS blend as shown by ATR-FTIR. The improved adhesion was also shown by the increased number of physical entanglements observed by SEM. It can be concluded that MDI can be used to improve wettability and adhesion between PLA/CS coating and PLA film.

  4. Preparation and investigation of polylactic acid, calcium carbonate and polyvinylalcohol nanofibrous scaffolds for osteogenic differentiation of mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    A. Doustgani

    2016-04-01

    Full Text Available Objective(s: In this study, the effect of electrospun fiber orientation on proliferation and differentiation of mesenchymal stem cells (MSCs was evaluated. Materials and Methods: Aligned and random nanocomposite nanofibrous scaffolds were electrospun from polylactic acid (PLA, poly (vinyl alcohol (PVA and calcium carbonate nanoparticles (nCaP. The surface morphology of prepared nanofibrous scaffolds with and without cell was examined using scanning electron microscopy. Mechanical properties of electrospun nanofibrous scaffolds were determined with a  universal testing machine. The in vitro properties of fabricated scaffolds was also investigated by the MTT assay and alkaline phosphatase activity (ALP.Results: The average fiber diameter for aligned and random nanofibers were 82 ± 12 nm and 124 ± 25 nm, respectively. The mechanical testing indicated the higher tensile strength and elastic modulus of aligned nanofibers. MTT and ALP results showed that alignment of nanofiber increased the osteogenic differentiation of stem cells.Conclusion: Aligned nanofibrous nanocomposite scaffolds of PLA/nCaP/PVA could be an excellent substrate for MSCs and represents a potential bone-filling material.

  5. Effectiveness of trimethylopropane trimethacrylate for the electron-beam-irradiation-induced cross-linking of polylactic acid

    Science.gov (United States)

    Ng, Hon-Meng; Bee, Soo-Tueen; Ratnam, C. T.; Sin, Lee Tin; Phang, Yee-Yao; Tee, Tiam-Ting; Rahmat, A. R.

    2014-01-01

    The purpose of this research was to investigate the effects of various loading levels of trimethylopropane trimethacrylate (TMPTMA) on the properties of polylactic acid (PLA) cross-linked via electron-beam irradiation. PLA was compounded with 3-5 wt.% of TMPTMA to induce cross-linking upon subjection to electron-beam irradiation doses of 25-250 kGy. The physical properties of the PLA samples were characterised by means of X-ray diffraction, gel fraction and scanning electron microscopy analyses on fractured surfaces after tensile tests. The presence of TMPTMA in PLA was found to effectively increase the crystallite size and gel fraction. However, higher loading levels of TMPTMA could compromise the properties of the PLA/TMPTMA samples, indicating that a larger amount of monomer free radicals might promote degradation within the substantially cross-linked amorphous phase. Irradiation-induced cross-linking in the samples could improve the cross-linking density while decreasing the elongation and interfering with the crystallisation. These effects are caused by the intensive irradiation-induced chain scission that is responsible for the deterioration of the mechanical and crystalline properties of the samples.

  6. Physical, Mechanical, and Thermal Analysis of Polylactic Acid/Fumed Silica/Clay (1.28E Nanocomposites

    Directory of Open Access Journals (Sweden)

    Josephine Chang Hui Lai

    2015-01-01

    Full Text Available Polylactic acid/fumed silica/clay (PLA/FS/clay (1.28E nanocomposites have been successfully prepared by solution-intercalation film-casting technique. The resultant nanocomposites were characterized by Fourier Transform Infrared Spectroscopy (FT-IR, Scanning Electron Microscopy (SEM, tensile test, thermogravimetric analysis (TGA, and moisture absorption test. The FT-IR spectrum indicated that PLA/FS/clay with 2 wt% had much broader peak compared to 5 wt%, 10 wt%, and 15 wt% nanocomposites. Incorporation of clay (1.28E with 2 wt% showed the best compatibility with PLA/FS matrix. PLA/FS/clay (1.28E nanocomposite with 2 wt% of clay loading had higher tensile strength and modulus compared to other nanocomposites. The thermal stability and activation energy of 2 wt% of PLA/FS/clay (1.28E nanocomposite are the highest among all the nanocomposites. The moisture absorbed into PLA/FS/clay (1.28E nanocomposite was significantly reduced with clay loading of 2 wt%.

  7. Impact behaviors of poly-lactic acid based biocomposite reinforced with unidirectional high-strength magnesium alloy wires

    Directory of Open Access Journals (Sweden)

    Xuan Li

    2014-10-01

    Full Text Available A novel poly-lactic acid (PLA based biocomposite reinforced with unidirectional high-strength magnesium alloy (Mg-alloy wires for bone fracture fixation was fabricated by hot-compressing process. The macroscopical and microscopical impact behaviors of the biocomposite were investigated using impact experiments and finite element method (FEM, respectively. The results indicated that the biocomposite had favorable impact properties due to the plastic deformation behavior of Mg-alloy wires during impact process. While the content of Mg-alloy wires reached 20 vol%, the impact strength of the composite could achieve 93.4 kJ/m2, which is approximate 16 times larger than that of pure PLA fabricated by the same process. According to FEM simulation results, the complete destruction life of the composites during impact process increased with increasing volume fraction of Mg-alloy wires, indicating a high impact-bearing ability of the composite for bone fracture fixation. Simultaneously, the energy absorbed by Mg-alloy wires in the composites had a corresponding increase. In addition, it denoted that the impact properties of the composites are sensitive to the initial properties of the matrix material.

  8. Effects Of Polylactic Acid Coating and Compression Load on the Delivery of Protein and Steroid from HA Ceramic Devices.

    Science.gov (United States)

    Benghuzzi, Hamed; Tucci, Michelle A; Ibrahim, Jamil

    2015-01-01

    Density variations, due to particle size and time and temperature of sintering, affect the delivery profile of substances from ceramic delivery devices. This investigation was conducted to study the effect of polylactic acid (PLA) impregnation on the porosity of hydroxyapatite (HA) capsules by studying the delivery rate of bovine serum albumin (BSA) and testosterone (TE). HA capsules were fabricated by cold compressing calcined particles at 1000, 3000, and 5000 lbs. Each group was subdivided into PLA-impregnated and non-PLA impregnated capsules. Each capsule was loaded with either 40 mg of TE (impregnated or nonimpregnated with PLA polymer) or BSA. Data obtained in this study suggest that: (1) PLA impregnation of HA ceramic capsules decreases the rate of release of drugs from the ceramic reservoir, (2) Physiochemical characteristics of the drugs to be delivered is an instrumental key in the sustained release profiles, (3) Compression load of HA reservoirs is a key factor in predicting the duration and level of sustained delivery, and (4) Polymer coating of HA ceramic capsules reduces the pore size, as well as, blocking some of the pores on the surface.

  9. Effect of Starch/Polylactic Acid Ratio on the Interdependence of Two-Phase and the Properties of Composites

    Institute of Scientific and Technical Information of China (English)

    ZUO Yingfeng; GU Jiyou; CAO Jun; WEI Shuangying; TAN Haiyan; ZHANG Yanhua

    2015-01-01

    Starch/polylactic acid (PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other properties of the composites were studied. The combination of results of TGA with SEM indicated that the interdependence between starch and PLA was increased gradually as the starch/PLA ratio reduced. DSC results showed that the glass transition temperature (Tg), melting temperature (Tm) and degree of crystallinity of PLA in composites were increased gradually, whereas the cold crystallization temperature (Tc) was gradually decreased as the starch/PLA ratio reduced. The rheological properties of composites were closely related with the interdependence of two-phase, with reducing starch/PLA proportion, the interdependence was increased, and then the strain for storage modulus was ifrstl reduced and then gradually increased. Frequency scanning showed that the storage modulus and complex viscosity were decreased with reducing starch content. As the starch/PLA ratio reduced, the matrix phase PLA was increased, so that the strength of composites was increased gradually, whereas water absorption rate was decreased gradually.

  10. Synthesis of graphene oxide grafted poly(lactic acid) with palladium nanoparticles and its application to serotonin sensing

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hyoung Soon; You, Jung-Min; Jeong, Haesang; Jeon, Seungwon, E-mail: swjeon3380@naver.com

    2013-11-01

    Graphene oxide (GO) has treated with methylene diphenyl diisocyanate (MDI) and subsequent 1,4-butanediol (BD) to create an anchoring OH site on the surface of GO (GO-MDI-OH). The OH groups of GO-MDI-OH were the initiators of the polymerization of poly(lactic acid) (PLA). The subsequent GO-g-PLA was synthesized by the polymerization reaction in the presence of GO-MDI-OH and PLA. The synthesized materials were characterized via {sup 1}H-NMR, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermal analysis (differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA)). The surface morphologies and degree of dispersions at G-g-PLA-metals were observed using a field emission scanning electron microscope (FE-SEM) and a transmission electron microscopy (TEM). The electrical conductivity of G-g-PLA-Pd was largely enhanced compared with those of GO and GO-g-PLA. G-g-PLA-Pd was used for the electrochemical detection of serotonin. Electrocatalytic activities were verified from the cyclic voltammetry (CV) and amperometric response in a 0.1 M phosphate buffer solution (PBS). A significantly higher concentration range (0.1–100.0 μM) and a lower detection limit (8.0 × 10{sup −8} M, where s/n = 3) were found at the G-g-PLA-Pd modified glassy carbon electrode (GCE).

  11. Osteogenesis of human adipose-derived stem cells on hydroxyapatite-mineralized poly(lactic acid) nanofiber sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kung, Fu-Chen [Department of Health Developing and Health Marketing, Kainan University, Taiwan (China); Lin, Chi-Chang, E-mail: chichang31@thu.edu.tw [Department of Chemical and Materials Engineering, Tunghai University, Taiwan (China); Lai, Wen-Fu T., E-mail: Laitw@tmu.edu.tw [Graduate Institute of Clinical Medicine, Taipei Medical University, Taiwan (China)

    2014-12-01

    Electrospun fiber sheets with various orientations (random, partially aligned, and aligned) and smooth and roughened casted membranes were prepared. Hydroxyapatite (HA) crystals were in situ formed on these material surfaces via immersion in 10 × simulated body fluid solution. The size and morphology of the resulting fibers were examined using scanning electron microscopy. The average diameter of the fibers ranged from 225 ± 25 to 1050 ± 150 nm depending on the electrospinning parameters. Biological experiment results show that human adipose-derived stem cells exhibit different adhesion and osteogenic differentiation on the three types of fiber. The cell proliferation and osteogenic differentiation were best on the aligned fibers. Similar results were found for phosphorylated focal adhesion kinase expression. Electrospun poly(lactic acid) aligned fibers mineralized with HA crystals provide a good environment for cell growth and osteogenic differentiation and thus have great potential in the tissue engineering field. - Highlights: • hADSCs show higher adhesion and proliferation on HA-precipitate electrospun fiber sheets than those of the control membranes. • HA-mineralized fiber groups greatly improve cell growth and increase FAK and p-FAK expressions. • HA-precipitate electrospun fiber sheets present higher ALP and OC activity through the study periods. • Electrospun PLA fiber mineralized with HA provides a good environment for cell growth and osteogenic differentiation. • A simple immersion of electrospun fibers in 10 × SBF are a potential matrix for bone tissue engineering.

  12. Mandibular bone repair by implantation of rhBMP-2 in a slow release carrier of polylactic acid--an experimental study in rats.

    OpenAIRE

    Schliephake, Henning; Weich, Herbert A.; Dullin, Christian; Gruber, Rudolf; Frahse, Sarah

    2008-01-01

    The aim of the present study was to test the hypothesis that human recombinant bone morphogenic protein 2 (rhBMP-2) implanted in a slow release carrier of polylactic acid (PLA) can repair a non-healing defect in the rat mandible and maintain the thickness of an augmented volume. p-DL-lactic acid discs were produced and loaded with 48 and 96 microg rhBMP-2 and inserted into non-healing defects of the mandible of 45 Wistar rats. Fifteen rats received implants with 96 microg rhBMP-2 (Group 2), 4...

  13. Experimental study Of polylactic acid foam as support carrier for culture of bone marrow stromal cells%聚乳酸吸附骨髓基质细胞修复软骨的实验研究

    Institute of Scientific and Technical Information of China (English)

    李保陆; 王勤; 王晶; 刘延青; 娄思权

    2001-01-01

    目的探索聚乳酸作为软骨组织工程载体材料的可行性。观察4、8、12周后软骨缺损的情况,并对组织切片评分。方法制备了聚乳酸(PLA)多孔泡沫,将吸附骨髓基质细胞的聚乳酸多孔膜植入兔膝关节软骨负重(内髁)和非负重区(外髁)缺损内。结果骨髓基质细胞可以修复关节软骨缺损。结论聚乳酸是适合吸附骨髓基质细胞修复软骨的载体材料。%Objective The foam of polylactic acid was prepared, the bone marrow stromal cells were absorbed by polylactic acid foam. Method We use the polylactic acid-cells complexes to repair the defects of rabbit articular cartilage in weight bearing and nonweight bearing area, to explore feasibility of polylactic acid as carrier materials in tissue engineering. After 4、8 、 12weeks the repair tissue was evaluated by histologic method. Result Bone marrow stromal cells are able to repair the detect of articular cartilage Conclusion The polylactic acid are fit carrier material for bone marrow stromal cell repair the detect of articular cartilage.

  14. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe.

    Science.gov (United States)

    Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H

    2015-12-01

    Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp=200...600 μm, porosity ε=0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol)=0 after t=6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest.

  15. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe

    Science.gov (United States)

    Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H.

    2015-12-01

    Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp = 200…600 μm, porosity ε = 0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol) = 0 after t = 6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest.

  16. Encapsulation of gallic acid/cyclodextrin inclusion complex in electrospun polylactic acid nanofibers: Release behavior and antioxidant activity of gallic acid.

    Science.gov (United States)

    Aytac, Zeynep; Kusku, Semran Ipek; Durgun, Engin; Uyar, Tamer

    2016-06-01

    Cyclodextrin-inclusion complexes (CD-ICs) possess great prominence in food and pharmaceutical industries due to their enhanced ability for stabilization of active compounds during processing, storage and usage. Here, CD-IC of gallic acid (GA) with hydroxypropyl-beta-cyclodextrin (GA/HPβCD-IC) was prepared and then incorporated into polylactic acid (PLA) nanofibers (PLA/GA/HPβCD-IC-NF) using electrospinning technique to observe the effect of CD-ICs in the release behavior of GA into three different mediums (water, 10% ethanol and 95% ethanol). The GA incorporated PLA nanofibers (PLA/GA-NFs) were served as control. Phase solubility studies showed an enhanced solubility of GA with increasing amount of HPβCD. The detailed characterization techniques (XRD, TGA and (1)H-NMR) confirmed the formation of inclusion complex between GA and HPβCD. Computational modeling studies indicated that the GA made an efficient complex with HPβCD at 1:1 either in vacuum or aqueous system. SEM images revealed the bead-free and uniform morphology of PLA/GA/HPβCD-IC-NF. The release studies of GA from PLA/GA/HPβCD-IC-NF and PLA/GA-NF were carried out in water, 10% ethanol and 95% ethanol, and the findings revealed that PLA/GA/HPβCD-IC-NF has released much more amount of GA in water and 10% ethanol system when compared to PLA/GA-NF. In addition, GA was released slowly from PLA/GA/HPβCD-IC-NF into 95% ethanol when compared to PLA/GA-NF. It was also observed that electrospinning process had no negative effect on the antioxidant activity of GA when GA was incorporated in PLA nanofibers.

  17. Antimicrobial activity of allyl isothiocyanate used to coat biodegradable composite films as affected by storage and handling conditions.

    Science.gov (United States)

    Li, Weili; Liu, Linshu; Jin, Tony Z

    2012-12-01

    We evaluated the effects of storage and handling conditions on the antimicrobial activity of biodegradable composite films (polylactic acid and sugar beet pulp) coated with allyl isothiocyanate (AIT). Polylactic acid and chitosan were incorporated with AIT and used to coat one side of the film. The films were subjected to different storage conditions (storage time, storage temperature, and packed or unpacked) and handling conditions (washing, abrasion, and air blowing), and the antimicrobial activity of the films against Salmonella Stanley in tryptic soy broth was determined. The films (8.16 μl of AIT per cm(2) of surface area) significantly (P packaging.

  18. Study on the capability of cinnamaldehyde polylactic acid film%肉桂醛聚乳酸膜性能的研究

    Institute of Scientific and Technical Information of China (English)

    王庆玲; 李翠翠; 田耀旗; 朱艳巧; 金征宇

    2012-01-01

    Based on the raw materials of polylactic acid,cinnamaldehyde-β-cyclodextrin and potato starch,cinnamaldehyde polylactic acid film was prepared,and its antibacterial and water-holding properties were studied in application of cake packaging.The results showed that the antibacterial effect of the film was positively correlated with the amount of the inclusion added under the conditions of 25℃ and relative humidity 50%.Furthermore,the water-holding capacity of the film was also positively correlated with the amount of potato starch.Cinnamaldehyde polylactic acid film including antibacterial and water-holding capability could effectively inhibit mold growth and prolong the shelf-life of the cake.%以聚乳酸、肉桂醛-β-环糊精包合物和马铃薯淀粉为原料制备了肉桂醛聚乳酸膜,并应用于蛋糕包装中研究了该膜的抗菌性和持水能力。结果表明,在环境温度为25℃和相对湿度50%的条件下,膜的抗菌效果与包合物的添加量呈正相关;当包合物的添加量一定时,膜的持水性能与马铃薯淀粉含量呈正相关。肉桂醛聚乳酸膜具有抗菌性和持水能力,能有效抑制蛋糕霉菌生长,延长了蛋糕的货架期。

  19. GX1-conjugated poly(lactic acid nanoparticles encapsulating Endostar for improved in vivo anticolorectal cancer treatment

    Directory of Open Access Journals (Sweden)

    Du Y

    2015-05-01

    Full Text Available Yang Du,1,* Qian Zhang,1,* Lijia Jing,2 Xiaolong Liang,2 Chongwei Chi,1 Yaqian Li,1 Xin Yang,1 Zhifei Dai,2 Jie Tian1 1Key Laboratory of Molecular Imaging, The State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, People’s Republic of China; 2Department of Biomedical Engineering, College of Engineering, Peking University, Beijing People’s Republic of China *These authors contributed equally to this work Abstract: Tumor angiogenesis plays a key role in tumor growth and metastasis; thus, targeting tumor-associated angiogenesis is an important goal in cancer therapy. However, the efficient delivery of drugs to tumors remains a key issue in antiangiogenesis therapy. GX1, a peptide identified by phage-display technology, is a novel tumor vasculature endothelium-specific ligand and possesses great potential as a targeted vector and antiangiogenic agent in the diagnosis and treatment of human cancers. Endostar, a novel recombinant human endostatin, has been shown to inhibit tumor angiogenesis. In this study, we developed a theranostic agent composed of GX1-conjugated poly(lactic acid nanoparticles encapsulating Endostar (GPENs and labeled with the near-infrared dye IRDye 800CW to improve colorectal tumor targeting and treatment efficacy in vivo. The in vivo fluorescence molecular imaging data showed that GPENs (IRDye 800CW more specifically targeted tumors than free IRDye 800CW in colorectal tumor-bearing mice. Moreover, the antitumor efficacy was evaluated by bioluminescence imaging and immunohistology, revealing that GPENs possessed improved antitumor efficacy on subcutaneous colorectal xenografts compared to other treatment groups. Thus, our study showed that GPENs, a novel GX1 peptide guided form of nanoscale Endostar, can be used as a theranostic agent to facilitate more efficient targeted therapy and enable real-time monitoring of therapeutic efficacy in vivo

  20. Reinforcement effect of poly(butylene succinate) (PBS)-grafted cellulose nanocrystal on toughened PBS/polylactic acid blends.

    Science.gov (United States)

    Zhang, Xuzhen; Zhang, Yong

    2016-04-20

    Poly(butylene succinate) (PBS)/polylactic acid (PLA) blends modified with dicumyl peroxide (DCP) were reinforced by PBS-g-cellulose nanocrystal (CNC) through melt mixing. PBS-g-CNC was prepared through in situ polymerization and its structure was confirmed by FTIR, (13)C NMR, XPS and GPC analysis after saponification. The morphological analysis of PBS/PLA/PBS-g-CNC composites before and after etched by CH2Cl2 shows that the addition of DCP and PBS-g-CNC could decrease the size of PBS as a dispersed phase in PLA matrix and improve the dispersion of PBS-g-CNC in both PBS and PLA phases, which could affect the crystallization and mechanical properties of composites. The crystallinity of PLA α'-phase crystal in PBS/PLA/PBS-g-CNC composites is increased obviously by the addition of PBS-g-CNC, leading to an increase of the crystallinity of the composites. PBS/PLA blends modified by DCP have high Notched Izod impact strength and moduli, and the values are increased by the addition of PBS-g-CNC. Both storage modulus and glass translation temperature of PBS/PLA blend are increased by DCP and PBS-g-CNC, which is proved by DMA results, showing a weak molecular segment mobility of PBS/PLA matrix. The addition of DCP decreases the crystallization temperature and crystallinity of PBS/PLA composite, but increases the thermal stability of composites, mostly because of the crosslink effect of DCP on PBS/PLA matrix.

  1. Magnetic Cellulose Nanocrystal Based Anisotropic Polylactic Acid Nanocomposite Films: Influence on Electrical, Magnetic, Thermal, and Mechanical Properties.

    Science.gov (United States)

    Dhar, Prodyut; Kumar, Amit; Katiyar, Vimal

    2016-07-20

    This paper reports a single-step co-precipitation method for the fabrication of magnetic cellulose nanocrystals (MGCNCs) with high iron oxide nanoparticle content (∼51 wt % loading) adsorbed onto cellulose nanocrystals (CNCs). X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman spectroscopic studies confirmed that the hydroxyl groups on the surface of CNCs (derived from the bamboo pulp) acted as anchor points for the adsorption of Fe3O4 nanoparticles. The fabricated MGCNCs have a high magnetic moment, which is utilized to orient the magnetoresponsive nanofillers in parallel or perpendicular orientations inside the polylactic acid (PLA) matrix. Magnetic-field-assisted directional alignment of MGCNCs led to the incorporation of anisotropic mechanical, thermal, and electrical properties in the fabricated PLA-MGCNC nanocomposites. Thermomechanical studies showed significant improvement in the elastic modulus and glass-transition temperature for the magnetically oriented samples. Differential scanning calorimetry (DSC) and XRD studies confirmed that the alignment of MGCNCs led to the improvement in the percentage crystallinity and, with the absence of the cold-crystallization phenomenon, finds a potential application in polymer processing in the presence of magnetic field. The tensile strength and percentage elongation for the parallel-oriented samples improved by ∼70 and 240%, respectively, and for perpendicular-oriented samples, by ∼58 and 172%, respectively, in comparison to the unoriented samples. Furthermore, its anisotropically induced electrical and magnetic properties are desirable for fabricating self-biased electronics products. We also demonstrate that the fabricated anisotropic PLA-MGCNC nanocomposites could be laminated into films with the incorporation of directionally tunable mechanical properties. Therefore, the current study provides a novel noninvasive approach of orienting nontoxic bioderived CNCs in the presence of low

  2. Reinforcement effect of poly(butylene succinate) (PBS)-grafted cellulose nanocrystal on toughened PBS/polylactic acid blends.

    Science.gov (United States)

    Zhang, Xuzhen; Zhang, Yong

    2016-04-20

    Poly(butylene succinate) (PBS)/polylactic acid (PLA) blends modified with dicumyl peroxide (DCP) were reinforced by PBS-g-cellulose nanocrystal (CNC) through melt mixing. PBS-g-CNC was prepared through in situ polymerization and its structure was confirmed by FTIR, (13)C NMR, XPS and GPC analysis after saponification. The morphological analysis of PBS/PLA/PBS-g-CNC composites before and after etched by CH2Cl2 shows that the addition of DCP and PBS-g-CNC could decrease the size of PBS as a dispersed phase in PLA matrix and improve the dispersion of PBS-g-CNC in both PBS and PLA phases, which could affect the crystallization and mechanical properties of composites. The crystallinity of PLA α'-phase crystal in PBS/PLA/PBS-g-CNC composites is increased obviously by the addition of PBS-g-CNC, leading to an increase of the crystallinity of the composites. PBS/PLA blends modified by DCP have high Notched Izod impact strength and moduli, and the values are increased by the addition of PBS-g-CNC. Both storage modulus and glass translation temperature of PBS/PLA blend are increased by DCP and PBS-g-CNC, which is proved by DMA results, showing a weak molecular segment mobility of PBS/PLA matrix. The addition of DCP decreases the crystallization temperature and crystallinity of PBS/PLA composite, but increases the thermal stability of composites, mostly because of the crosslink effect of DCP on PBS/PLA matrix. PMID:26876864

  3. Development of poly(lactic acid) nanostructured membranes for the controlled delivery of progesterone to livestock animals

    International Nuclear Information System (INIS)

    Solution blow spinning (SBS) is a novel technology feasible to produce nanostructured polymeric membranes loaded with active agents. In the present study, nanofibrous mats of poly(lactic acid) (PLA) loaded with progesterone (P4) were produced by SBS at different P4 concentrations. The spun membranes were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). The in vitro releasing of P4 was evaluated using high-performance liquid chromatography (HPLC). Interactions between progesterone and PLA were confirmed by rheological measurements of the PLA/P4 solutions and in the spun mats by microscopy (SEM), thermal (DSC) and spectral (FTIR) analyses. SEM micrographs provided evidences of a smooth and homogeneous structure for nanostructured membranes without progesterone crystals on fiber surface. FTIR spectroscopy indicated miscibility and interaction between the ester of PLA and the ketone groups of the P4 in the nanofibers. X-ray analysis indicated that the size of PLA crystallites increased with progesterone content. Finally, by in vitro release experiments it was possible to observe that the progesterone releasing follows nearly first-order kinetics, probably due to the diffusion of hormone into PLA nanofibers. - Highlights: ► Nanofibers of PLA loading with progesterone were prepared via solution blow spinning. ► Their morphology, FTIR, and XRD and DSC characterization were analyzed. ► Fibers of PLA/progesterone with diameters from 280 to 440 nm were obtained. ► The effect of progesterone content in fiber properties was studied.

  4. Development of poly(lactic acid) nanostructured membranes for the controlled delivery of progesterone to livestock animals

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Juliano Elvis [Laboratorio Nacional de Nanotecnologia para o Agronegocio (LNNA), Embrapa Instrumentacao (CNPDIA), Rua XV de Novembro, 1452, Centro, 13.560, 970 Sao Carlos, SP (Brazil); Medeiros, Eliton Souto [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia de Materiais (DEMAT), Cidade Universitaria, 58.051-900, Joao Pessoa, PB (Brazil); Cardozo, Lucio; Voll, Fernando [Departamento de Engenharia Quimica, Universidade Estadual de Maringa (UEM), 87.020, 900 Maringa, PR (Brazil); Madureira, Ed Hoffmann [Departamento de Reproducao Animal, Faculdade de Medicina Veterinaria e Zootecnia (FMVZ), Universidade de Sao Paulo (USP), Pirassununga-SP (Brazil); Mattoso, Luiz Henrique Capparelli, E-mail: mattoso@cnpdia.embrapa.br [Laboratorio Nacional de Nanotecnologia para o Agronegocio (LNNA), Embrapa Instrumentacao (CNPDIA), Rua XV de Novembro, 1452, Centro, 13.560, 970 Sao Carlos, SP (Brazil); Assis, Odilio Benedito Garrido [Laboratorio Nacional de Nanotecnologia para o Agronegocio (LNNA), Embrapa Instrumentacao (CNPDIA), Rua XV de Novembro, 1452, Centro, 13.560, 970 Sao Carlos, SP (Brazil)

    2013-03-01

    Solution blow spinning (SBS) is a novel technology feasible to produce nanostructured polymeric membranes loaded with active agents. In the present study, nanofibrous mats of poly(lactic acid) (PLA) loaded with progesterone (P4) were produced by SBS at different P4 concentrations. The spun membranes were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). The in vitro releasing of P4 was evaluated using high-performance liquid chromatography (HPLC). Interactions between progesterone and PLA were confirmed by rheological measurements of the PLA/P4 solutions and in the spun mats by microscopy (SEM), thermal (DSC) and spectral (FTIR) analyses. SEM micrographs provided evidences of a smooth and homogeneous structure for nanostructured membranes without progesterone crystals on fiber surface. FTIR spectroscopy indicated miscibility and interaction between the ester of PLA and the ketone groups of the P4 in the nanofibers. X-ray analysis indicated that the size of PLA crystallites increased with progesterone content. Finally, by in vitro release experiments it was possible to observe that the progesterone releasing follows nearly first-order kinetics, probably due to the diffusion of hormone into PLA nanofibers. - Highlights: Black-Right-Pointing-Pointer Nanofibers of PLA loading with progesterone were prepared via solution blow spinning. Black-Right-Pointing-Pointer Their morphology, FTIR, and XRD and DSC characterization were analyzed. Black-Right-Pointing-Pointer Fibers of PLA/progesterone with diameters from 280 to 440 nm were obtained. Black-Right-Pointing-Pointer The effect of progesterone content in fiber properties was studied.

  5. Inactivation of Listeria monocytogenes in skim milk and liquid egg white by antimicrobial bottle coating with polylactic acid and nisin.

    Science.gov (United States)

    Jin, Tony

    2010-03-01

    This study was to develop an antimicrobial bottle coating method to reduce the risk of outbreaks of human listeriosis caused by contaminated liquid foods. Liquid egg white and skim milk were inoculated with Listeria monocytogenes Scott A and stored in glass jars that were coated with a mixture of polylactic acid (PLA) polymer and nisin. The efficacy of PLA per nisin coating in inactivating L. monocytogenes was investigated at 10 and 4 degrees C. The pathogen grew well in skim milk without PLA/nisin coating treatments, reaching 8 log CFU/mL after 10 d and then remained constant up to 42 d at 10 degrees C. The growth of Listeria at 4 degrees C was slower than that at 10 degrees C, taking 21 d to obtain 8 log CFU/mL. At both storage temperatures, the PLA coating with 250 mg nisin completely inactivated the cells of L. monocytogenes after 3 d and throughout the 42-d storage period. In liquid egg white, Listeria cells in control and PLA coating without nisin samples declined 1 log CFU/mL during the first 6 d at 10 degrees C and during 28 d at 4 degrees C, and then increased to 8 or 5.5 log CFU/mL. The treatment of PLA coating with 250 mg nisin rapidly reduced the cell numbers of Listeria in liquid egg white to undetectable levels after 1 d, then remained undetectable throughout the 48 d storage period at 10 degrees C and the 70 d storage period at 4 degrees C. These data suggested that the PLA/nisin coating treatments effectively inactivated the cells of L. monocytogenes in liquid egg white and skim milk samples at both 10 and 4 degrees C. This study demonstrated the commercial potential of applying the antimicrobial bottle coating method to milk, liquid eggs, and possibly other fluid products. PMID:20492246

  6. A Novel Hierarchical Structured Poly(lactic acid/Titania Fibrous Membrane with Excellent Antibacterial Activity and Air Filtration Performance

    Directory of Open Access Journals (Sweden)

    Zhe Wang

    2016-01-01

    Full Text Available Hybrid poly(lactic acid/titania (PLA/TiO2 fibrous membranes exhibiting excellent air filtration performance and good antibacterial activity were prepared via the electrospinning technique. By varying the composition of the precursor solutions and the relative humidity, the morphologies of PLA/TiO2 fibers, including the nanopores and nanometer-scale protrusions on the surface of the fibers, could be regulated. The distribution of nanopores and TiO2 nanoparticles on the surface of PLA/TiO2 fibers was investigated. Nitrogen adsorption-desorption analysis revealed that nanopores and nanometer-scale protrusions play an important role in improving the specific surface area and nanopore volume of the relevant PLA/TiO2 fibrous membrane. Filtration performance tests conducted by measuring the penetration of sodium chloride aerosol particles with a 260 nm mass median diameter indicated that fibers with a high surface roughness, large specific surface area, and large nanopore volume greatly improved the particle capture efficiency and facilitated the penetration of airflow. Furthermore, the introduction of TiO2 nanoparticles endows the relevant fibrous membrane with antibacterial properties. The as-prepared PLA/TiO2 fibrous membrane loaded with 1.75 wt% TiO2 nanoparticles formed at a relative humidity of 45% exhibited a high filtration efficiency (99.996% and a relatively low pressure drop (128.7 Pa, as well as a high antibacterial activity of 99.5%.

  7. Magnetic Cellulose Nanocrystal Based Anisotropic Polylactic Acid Nanocomposite Films: Influence on Electrical, Magnetic, Thermal, and Mechanical Properties.

    Science.gov (United States)

    Dhar, Prodyut; Kumar, Amit; Katiyar, Vimal

    2016-07-20

    This paper reports a single-step co-precipitation method for the fabrication of magnetic cellulose nanocrystals (MGCNCs) with high iron oxide nanoparticle content (∼51 wt % loading) adsorbed onto cellulose nanocrystals (CNCs). X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman spectroscopic studies confirmed that the hydroxyl groups on the surface of CNCs (derived from the bamboo pulp) acted as anchor points for the adsorption of Fe3O4 nanoparticles. The fabricated MGCNCs have a high magnetic moment, which is utilized to orient the magnetoresponsive nanofillers in parallel or perpendicular orientations inside the polylactic acid (PLA) matrix. Magnetic-field-assisted directional alignment of MGCNCs led to the incorporation of anisotropic mechanical, thermal, and electrical properties in the fabricated PLA-MGCNC nanocomposites. Thermomechanical studies showed significant improvement in the elastic modulus and glass-transition temperature for the magnetically oriented samples. Differential scanning calorimetry (DSC) and XRD studies confirmed that the alignment of MGCNCs led to the improvement in the percentage crystallinity and, with the absence of the cold-crystallization phenomenon, finds a potential application in polymer processing in the presence of magnetic field. The tensile strength and percentage elongation for the parallel-oriented samples improved by ∼70 and 240%, respectively, and for perpendicular-oriented samples, by ∼58 and 172%, respectively, in comparison to the unoriented samples. Furthermore, its anisotropically induced electrical and magnetic properties are desirable for fabricating self-biased electronics products. We also demonstrate that the fabricated anisotropic PLA-MGCNC nanocomposites could be laminated into films with the incorporation of directionally tunable mechanical properties. Therefore, the current study provides a novel noninvasive approach of orienting nontoxic bioderived CNCs in the presence of low

  8. Poly(ε-caprolactone)/triclosan loaded polylactic acid nanoparticles composite: A long-term antibacterial bionanocomposite with sustained release.

    Science.gov (United States)

    Kaffashi, Babak; Davoodi, Saeed; Oliaei, Erfan

    2016-07-11

    In this study, the antibacterial bionanocomposites of poly(ε-caprolactone) (PCL) with different concentrations of triclosan (TC) loaded polylactic acid (PLA) nanoparticles (30wt% triclosan) (LATC30) were fabricated via a melt mixing process in order to lower the burst release of PCL and to extend the antibacterial activity during its performance. Due to the PLA's higher glass transition temperature (Tg) and less flexibility compared with PCL; the PLA nanoparticles efficiently trapped the TC particles, reduced the burst release of TC from the bionanocomposites; and extended the antibacterial property of the samples up to two years. The melt mixing temperature was adjusted to a temperature lower than the melting point of LATC30 nanoparticles; therefore, these nanoparticles were dispersed in the PCL matrix without any chemical reaction and/or drug extraction. The sustained release behavior of TC from PCL remained unchanged since no significant changes occurred in the samples' crystallinity compared with that in the neat PCL. The elastic moduli of samples were enhanced once LATC30 is included. This is necessary since the elastic modulus is decreased with water absorption. The rheological behaviors of samples showed appropriate properties for melt electro-spinning. A stable process was established as the relaxation time of the bionanocomposites was increased. The hydrophilic properties of samples were increased with increasing LATC30. The proliferation rate of the fibroblast (L929) cells was enhanced as the content of nanoparticles was increased. A system similar to this could be implemented to prepare long-term antibacterial and drug delivery systems based on PCL and various low molecular weight drugs. The prepared bionanocomposites are considered as candidates for the soft connective tissue engineering and long-term drug delivery.

  9. Improved wettability and adhesion of polylactic acid/chitosan coating for bio-based multilayer film development

    Energy Technology Data Exchange (ETDEWEB)

    Gartner, Hunter [School of Packaging, Michigan State University, East Lansing, Michigan (United States); Li, Yana [Mechanical Engineering College, Wuhan Polytechnic University (China); Almenar, Eva, E-mail: ealmenar@msu.edu [School of Packaging, Michigan State University, East Lansing, Michigan (United States)

    2015-03-30

    Graphical abstract: - Highlights: • Surface tension between PLA/CS blend solution and PLA film modified by MDI. • Better wettability between PLA/CS blend solution and PLA film by increasing MDI. • Increased breaking strength by increasing MDI due to the increased H-bonding. • Increased number of physical entanglements between PLA/CS coating and PLA film. • Development of a suitable bio-based multilayer film for food packaging applications. - Abstract: The objective of this study was to investigate the effect of methyldiphenyl diisocyanate (MDI) concentration (0, 0.2, 1, 2, and 3%) on the wettability and adhesion of blend solutions of poly(lactic acid) (PLA) and chitosan (CS) when coated on PLA film for development of a bio-based multi-layer film suitable for food packaging and other applications. Characterization was carried out by attenuated total reflectance infrared spectrometry (ATR-FTIR), contact angle (θ), mechanical adhesion pull-off testing, and scanning electron microscopy (SEM). The θ of the PLA/CS blend shifted to a lower value (41–35°) with increasing MDI concentration showing that the surface tension was modified between the PLA/CS blend solution and PLA film and better wettability was achieved. The increase in MDI also resulted in an increased breaking strength (228–303 kPa) due to the increased H-bonding resulting from the more urethane groups formed within the PLA/CS blend as shown by ATR-FTIR. The improved adhesion was also shown by the increased number of physical entanglements observed by SEM. It can be concluded that MDI can be used to improve wettability and adhesion between PLA/CS coating and PLA film.

  10. Polylactic acid/zinc oxide biocomposite films for food packaging application.

    Science.gov (United States)

    Marra, Antonella; Silvestre, Clara; Duraccio, Donatella; Cimmino, Sossio

    2016-07-01

    Although PLA is much more expensive than polyolefins, such as PP and PE, there is a great interest to propose PLA based material as alternative films for food packaging being PLA derivable from natural source, compostable and biodegradable. For this purpose the research has the task to investigate and propose PLA materials with enhanced properties to be effectively and efficiently alternative to polyolefin films for food packaging application. In this contribution, biocomposite films of PLA with 1, 3 and 5wt% of ZnO have been investigated to determine mechanical, barrier and antimicrobial (against Escherichia coli) properties. It is found that the biocomposite films are characterized by a good dispersion of the ZnO particles in PLA matrix, although no previous treatment was performed on ZnO particles, such as silanization, to decrease its incompatibility with the polymer. The biocomposite films have shown good mechanical properties, decrease of permeability to CO2 and O2, and only a slight increase to water vapour. Particularly important is that, for the biocomposite with 5wt% of ZnO, the % Reduction for E. Coli test reached the value of 99.99 already after 24h. PMID:27012896

  11. Polylactic acid/zinc oxide biocomposite films for food packaging application.

    Science.gov (United States)

    Marra, Antonella; Silvestre, Clara; Duraccio, Donatella; Cimmino, Sossio

    2016-07-01

    Although PLA is much more expensive than polyolefins, such as PP and PE, there is a great interest to propose PLA based material as alternative films for food packaging being PLA derivable from natural source, compostable and biodegradable. For this purpose the research has the task to investigate and propose PLA materials with enhanced properties to be effectively and efficiently alternative to polyolefin films for food packaging application. In this contribution, biocomposite films of PLA with 1, 3 and 5wt% of ZnO have been investigated to determine mechanical, barrier and antimicrobial (against Escherichia coli) properties. It is found that the biocomposite films are characterized by a good dispersion of the ZnO particles in PLA matrix, although no previous treatment was performed on ZnO particles, such as silanization, to decrease its incompatibility with the polymer. The biocomposite films have shown good mechanical properties, decrease of permeability to CO2 and O2, and only a slight increase to water vapour. Particularly important is that, for the biocomposite with 5wt% of ZnO, the % Reduction for E. Coli test reached the value of 99.99 already after 24h.

  12. Direct investigations on strain-induced cold crystallization behavior and structure evolutions in amorphous poly(lactic acid) with SAXS and WAXS measurements

    DEFF Research Database (Denmark)

    Zhou, Chengbo; Li, Hongfei; Zhang, Wenyang;

    2016-01-01

    in strain-induced crystallization behavior of amorphous PLA within 70-90 degrees C can be attributed to the competition between chain orientation caused by stretching and chain relaxation. It was proposed that the strain-induced mesocrystal/crystal and the lamellae are formed from the mesophase originally......Strain-induced cold crystallization behavior and structure evolution of amorphous poly(lactic acid) (PLA) stretched within 70-90 degrees C were investigated via in situ synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) measurements as well as differential...

  13. Reducing Water Vapor Permeability of Poly(lactic acid Film and Bottle through Layer-by-Layer Deposition of Green-Processed Cellulose Nanocrystals and Chitosan

    Directory of Open Access Journals (Sweden)

    Katalin Halász

    2015-01-01

    Full Text Available Layer-by-layer electrostatic self-assembly technique was applied to improve the barrier properties of poly(lactic acid (PLA films and bottles. The LbL process was carried out by the alternate adsorption of chitosan (CH (polycation and cellulose nanocrystals (CNC produced via ultrasonic treatment. Four bilayers (on each side of chitosan and cellulose nanocrystals caused 29 and 26% improvement in barrier properties in case of films and bottles, respectively. According to the results the LbL process with CH and CNC offered a transparent “green” barrier coating on PLA substrates.

  14. Progress in the research of polylactic acid materials used in bone repair%聚乳酸类骨修复材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    赵建华; 廖维宏; 陈建梅

    2003-01-01

    聚乳酸有良好的组织相容性和生物降解性,在骨组织工程中得到深入研究.本文就近年来聚乳酸(polylactic acid,PLA)的研究进展,包括PLA的性质与材料性能、PLA在骨组织工程的支架材料、引导性骨再生膜、复合人工骨的应用研究进行综述.

  15. Research Development of Improving the Mipor Foamability of Polylactic Acid%提高聚乳酸微孔发泡性能的研究进展

    Institute of Scientific and Technical Information of China (English)

    王雷

    2015-01-01

    本文就聚乳酸超临界CO2发泡技术方面的进展问题展开了系统的介绍,主要涉及了到PLA微孔塑料的优势,和对提高其发泡性能的研究。%This paper introduces the development problems of the supercritical CO2 foaming technology of polylactic acid, it mainly involves to the advantages of PLA mipor plastics and the research of improving its foamability.

  16. Poly (Ethylene Glycol) Modified Poly(Lactic Acid) and its applications in drug carrier%聚乙二醇改性聚乳酸及其在药物载体中的应用

    Institute of Scientific and Technical Information of China (English)

    徐春生; 朱宏

    2013-01-01

    Preparation methods of polyethylene glycol modified polylactic acid and their terminated group change is reviewed in the paper.And introduce the research progress of Polyethylene glycol-polylactic acid (PEG-PLA) block copolymer as drug carrier,prospects on future research were discussed.%综述了聚乙二醇改性聚乳酸及其端基化的制备方法,介绍了聚乙二醇-聚乳酸嵌段共聚物作为药物载体的研究进展,并对今后的研究进行了展望.

  17. A polylactic acid non-woven nerve conduit for facial nerve regeneration in rats.

    Science.gov (United States)

    Matsumine, Hajime; Sasaki, Ryo; Yamato, Masayuki; Okano, Teruo; Sakurai, Hiroyuki

    2014-06-01

    This study developed a biodegradable nerve conduit with PLA non-woven fabric and evaluated its nerve regeneration-promoting effect. The buccal branch of the facial nerve of 8 week-old Lewis rats was exposed, and a 7 mm nerve defect was created. A nerve conduit made of either PLA non-woven fabric (mean fibre diameter 460 nm), or silicone tube filled with type I collagen gel, or an autologous nerve, was implanted into the nerve defect, and their nerve regenerative abilities were evaluated 13 weeks after the surgery. The number of myelinated neural fibres in the middle portion of the regenerated nerve was the highest for PLA tubes (mean ± SD, 5051 ± 2335), followed by autologous nerves (4233 ± 590) and silicone tubes (1604 ± 148). Axon diameter was significantly greater in the PLA tube group (5.17 ± 1.69 µm) than in the silicone tube group (4.25 ± 1.60 µm) and no significant difference was found between the PLA tube and autograft (5.53 ± 1.93 µm) groups. Myelin thickness was greatest for the autograft group (0.65 ± 0.24 µm), followed by the PLA tube (0.54 ± 0.18 µm) and silicone tube (0.38 ± 0.12 µm) groups, showing significant differences among the three groups. The PLA non-woven fabric tube, composed of randomly-connected PLA fibres, is porous and has a number of advantages, such as sufficient strength to maintain luminal structure. The tube has demonstrated a comparable ability to induce peripheral nerve regeneration following autologous nerve transplantation.

  18. Biodegradation of novel amino acid derivatives suitable for complexing agents in pulp bleaching applications.

    Science.gov (United States)

    Metsärinne, Sirpa; Ronkainen, Erja; Tuhkanen, Tuula; Aksela, Reijo; Sillanpää, Mika

    2007-05-01

    The biodegradability of four novel diethanolamine derivative complexing agents was examined by using two biodegradation tests standardised by OECD (301B and 301F). Ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) were employed as reference substances. Biodegradation of the new complexing agents was studied both with unacclimated and acclimated inocula as well as by simulating wastewater treatment in sequencing batch reactors (SBRs). These new complexing agents were of technical grade, and therefore, the results are only indicative but these new compounds hold promise for use as complexing agents in the pulp and paper industry. The novel complexing agents were not readily biodegradable but they showed slight biodegradation. Around 10-30% degradation was found in the SBR where degradation was followed by measurement of concentration. Moreover the novel complexing agents did not have any negative impact on reactor performance as measured by chemical oxygen demand reduction. In the standardised biodegradation tests at best around 50% degradation was observed with the acclimated inoculum and in the prolonged test whereas EDTA and DTPA exhibited no biodegradation. The elevated degradation in acclimated sludge indicates that the water treatment plant microbes are capable of decomposing these molecules under favourable conditions. The total concentration of novel complexing agents decreased slightly during biodegradation tests, while the EDTA and DTPA concentrations remained stable. PMID:17346781

  19. Polylactic acid based materials and nanostructured multilayers for cardiovascular devices and wound healing

    OpenAIRE

    Carmagnola, Irene

    2013-01-01

    i. Poly(L-lactic acid), which is the current gold standard to fabricate bioresorbable stents, was modified by blending, with the aim to prepare a material with lower degradation time and improved mechanical properties. Binary blends of poly(L-lactic) acid (PLLA1: 80428 Da and PLLA2: 201790 Da) and poly(lactide-co-glycolide) (PLGA1) (LA:GA = 50:50 mol:mol; 32030 Da) with various compositions (100/0; 75/25: 50/50; 25/75; 0/100 wt./wt.) were prepared by solution casting. SEM analysis showed a bi...

  20. Nanoamphiphilic Chitosan Dispersed Poly(lactic acid) Bionanocomposite Films with Improved Thermal, Mechanical, and Gas Barrier Properties.

    Science.gov (United States)

    Pal, Akhilesh Kumar; Katiyar, Vimal

    2016-08-01

    This article demonstrates the synthesis of lactic acid oligomer-grafted-chitosan (OLLA-g-CH), a nanoamphiphilic molecule, by in situ condensation polymerization and its effective use as a nanofiller for improvement in multiple properties of poly(lactic acid) (PLA) films, essential for stringent food packaging applications. Fourier transform infrared spectroscopy (FTIR) analysis shows the presence of amide-ester bond at 1539 cm(-1), which confirms the structural grafting of OLLA chains with chitosan molecules. This nanoamphiphilic OLLA-g-CH molecule act as surfactant containing hydrophilic chitosan head and hydrophobic OLLA tails with average size in the range of ∼2-4 nm. Prepared PLA/OLLA-g-CH bionanocomposite films appear with uniform dispersion of nanoamphiphilic OLLA-g-CH molecules with self-assembled micelles having size as low as ∼20 nm and as high as ∼150 nm with core-shell morphology in PLA matrix. This nanofiller is found very effective toward significant reduction in oxygen permeability (OP) by ∼10-fold due to the reduction in solubility of oxygen molecules and improvement in crystal nucleation density due to availability of nanonucleating sites. Ultimate tensile strength (UTS) of PLA/OLLA-g-CH bionanocomposite films are relatively comparable to that of PLA, however, elongation at break is improved significantly. The onset of thermal degradation of PLA/(OLLA-g-CH) films is also found comparable to that of PLA film. The glass transition temperature (Tg) of bionanocomposites is decreased by more than 18 °C with increase in OLLA-g-CH loading, which indicates the improved plasticization characteristics of PLA matrix. The crystallization kinetics suggest nonthree dimensional truncated spherical structures, which is controlled by the combination of thermal and athermal instantaneous nucleations. POM analysis suggested that the spherulite growth of PLA is improved significantly with the addition of OLLA-g-CH. The reduction in Tg of PLA with improvement

  1. Preparation and evaluation of 17-allyamino-17-demethoxygeldanamycin (17-AAG)-loaded poly(lactic acid-co-glycolic acid) nanoparticles.

    Science.gov (United States)

    Pradhan, Roshan; Poudel, Bijay Kumar; Choi, Ju Yeon; Choi, Im Soon; Shin, Beom Soo; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2015-01-01

    In the present study, we developed the novel 17-allyamino-17-demethoxygeldanamycin (17-AAG)-loaded poly(lactic acid-co-glycolic acid) (PLGA) nanoparticles (NPs) using the combination of sodium lauryl sulfate and poloxamer 407 as the anionic and non-ionic surfactant for stabilization. The PLGA NPs were prepared by emulsification/solvent evaporation method. Both the drug/polymer ratio and phase ratio were 1:10 (w/w). The optimized formulation of 17-AAG-loaded PLGA NPs had a particle size and polydispersity index of 151.6 ± 2.0 and 0.152 ± 0.010 nm, respectively, which was further supported by TEM image. The encapsulation efficiency and drug loading capacity were 69.9 and 7.0%, respectively. In vitro release study showed sustained release. When in vitro release data were fitted to Korsmeyer-Peppas model, the n value was 0.468, which suggested that the drug was released by anomalous or non-Fickian diffusion. In addition, 17-AAG-loaded PLGA NPs in 72 h, displayed approximately 60% cell viability reduction at 10 µg/ml 17-AAG concentration, in MCF-7 cell lines, indicating sustained release from NPs. Therefore, our results demonstrated that incorporation of 17-AAG into PLGA NPs could provide a novel effective nanocarrier for the treatment of cancer.

  2. Polyglycolic acid-polylactic acid scaffold response to different progenitor cell in vitro cultures: a demonstrative and comparative X-ray synchrotron radiation phase-contrast microtomography study.

    Science.gov (United States)

    Giuliani, Alessandra; Moroncini, Francesca; Mazzoni, Serena; Belicchi, Marzia Laura Chiara; Villa, Chiara; Erratico, Silvia; Colombo, Elena; Calcaterra, Francesca; Brambilla, Lucia; Torrente, Yvan; Albertini, Gianni; Della Bella, Silvia

    2014-04-01

    Spatiotemporal interactions play important roles in tissue development and function, especially in stem cell-seeded bioscaffolds. Cells interact with the surface of bioscaffold polymers and influence material-driven control of cell differentiation. In vitro cultures of different human progenitor cells, that is, endothelial colony-forming cells (ECFCs) from a healthy control and a patient with Kaposi sarcoma (an angioproliferative disease) and human CD133+ muscle-derived stem cells (MSH 133+ cells), were seeded onto polyglycolic acid-polylactic acid scaffolds. Three-dimensional (3D) images were obtained by X-ray phase-contrast microtomography (micro-CT) and processed with the Modified Bronnikov Algorithm. The method enabled high spatial resolution detection of the 3D structural organization of cells on the bioscaffold and evaluation of the way and rate at which cells modified the construct at different time points from seeding. The different cell types displayed significant differences in the proliferation rate. In conclusion, X-ray synchrotron radiation phase-contrast micro-CT analysis proved to be a useful and sensitive tool to investigate the spatiotemporal pattern of progenitor cell organization on a bioscaffold.

  3. Long-term sustained release of salicylic acid from cross-linked biodegradable polyester induces a reduced foreign body response in mice.

    Science.gov (United States)

    Chandorkar, Yashoda; Bhaskar, Nitu; Madras, Giridhar; Basu, Bikramjit

    2015-02-01

    There has been a continuous surge toward developing new biopolymers that exhibit better in vivo biocompatibility properties in terms of demonstrating a reduced foreign body response (FBR). One approach to mitigate the undesired FBR is to develop an implant capable of releasing anti-inflammatory molecules in a sustained manner over a long time period. Implants causing inflammation are also more susceptible to infection. In this article, the in vivo biocompatibility of a novel, biodegradable salicylic acid releasing polyester (SAP) has been investigated by subcutaneous implantation in a mouse model. The tissue response to SAP was compared with that of a widely used biodegradable polymer, poly(lactic acid-co-glycolic acid) (PLGA), as a control over three time points: 2, 4, and 16 weeks postimplantation. A long-term in vitro study illustrates a continuous, linear (zero order) release of salicylic acid with a cumulative mass percent release rate of 7.34 × 10(-4) h(-1) over ∼1.5-17 months. On the basis of physicochemical analysis, surface erosion for SAP and bulk erosion for PLGA have been confirmed as their dominant degradation modes in vivo. On the basis of the histomorphometrical analysis of inflammatory cell densities and collagen distribution as well as quantification of proinflammatory cytokine levels (TNF-α and IL-1β), a reduced foreign body response toward SAP with respect to that generated by PLGA has been unambiguously established. The favorable in vivo tissue response to SAP, as manifest from the uniform and well-vascularized encapsulation around the implant, is consistent with the decrease in inflammatory cell density and increase in angiogenesis with time. The above observations, together with the demonstration of long-term and sustained release of salicylic acid, establish the potential use of SAP for applications in improved matrices for tissue engineering and chronic wound healing.

  4. Biodegradability of poly(lactic-co-glycolic acid) after femtosecond laser irradiation

    Science.gov (United States)

    Shibata, Akimichi; Yada, Shuhei; Terakawa, Mitsuhiro

    2016-06-01

    Biodegradation is a key property for biodegradable polymer-based tissue scaffolds because it can provide suitable space for cell growth as well as tailored sustainability depending on their role. Ultrashort pulsed lasers have been widely used for the precise processing of optically transparent materials, including biodegradable polymers. Here, we demonstrated the change in the biodegradation of a poly(lactic-co-glycolic acid) (PLGA) following irradiation with femtosecond laser pulses at different wavelengths. Microscopic observation as well as water absorption and mass change measurement revealed that the biodegradation of the PLGA varied significantly depending on the laser wavelength. There was a significant acceleration of the degradation rate upon 400 nm-laser irradiation, whereas 800 nm-laser irradiation did not induce a comparable degree of change. The X-ray photoelectron spectroscopy analysis indicated that laser pulses at the shorter wavelength dissociated the chemical bonds effectively, resulting in a higher degradation rate at an early stage of degradation.

  5. Effect of surface modification of poly(lactic acid) by low-pressure ammonia plasma on adsorption of human serum albumin

    International Nuclear Information System (INIS)

    Highlights: • Poly(lactic acid) (PLA) films were treated by low-pressure ammonia plasma. • Human serum albumin (HSA) attachment on the treated PLA was reduced. • The treated PLA films were characterized. • Hydrophilicity enhancement due to polar groups introduced was the reason. • Reduced HSA adhesion could promote cell attachment on PLA for biomedicine. - Abstract: The final goal of the study was to promote understanding of mechanisms involved in cell attachment on biomedical polymer poly(lactic acid) (PLA). As the cell attachment on the material surface was preceded by blood protein adsorption which would critically affect subsequent cell adhesion, for the clinic application purpose, human serum albumin (HSA) was used in the investigation on its adsorption on PLA, which was however treated by low-pressure ammonia (NH3) plasma. The NH3-plasma-treated PLA was found to adsorb less HSA than the untreated PLA. The PLA was characterized using various techniques such as atomic force microscopy, contact angle and surface energy analysis and x-ray photoelectron spectroscopy. All of the characterization results indicated that due to NH3-plasma-induced polar groups the PLA enhanced its hydrophilicity which in turn inhibited the HSA adsorption. The decreased HSA adsorption would consequently increase the cell attachment because of the cell adhesion barrier reduced

  6. A biomimetic multilayer nanofiber fabric fabricated by electrospinning and textile technology from polylactic acid and Tussah silk fibroin as a scaffold for bone tissue engineering.

    Science.gov (United States)

    Shao, Weili; He, Jianxin; Han, Qiming; Sang, Feng; Wang, Qian; Chen, Li; Cui, Shizhong; Ding, Bin

    2016-10-01

    To engineer bone tissue, a scaffold with good biological properties should be provided to approximate the hierarchical structure of collagen fibrils in natural bone. In this study, we fabricated a novel scaffold consisting of multilayer nanofiber fabrics (MLNFFs) by weaving nanofiber yarns of polylactic acid (PLA) and Tussah silk fibroin (TSF). The yarns were fabricated by electrospinning, and we found that spinnability, as well as the mechanical properties of the resulting scaffold, was determined by the ratio between polylactic acid and Tussah silk fibroin. In particular, a 9:1 mixture can be spun continuously into nanofiber yarns with narrow diameter distribution and good mechanical properties. Accordingly, woven scaffolds based on this mixture had excellent mechanical properties, with Young's modulus 417.65MPa and tensile strength 180.36MPa. For nonwoven scaffolds fabricated from the same materials, the Young's modulus and tensile strength were 2- and 4-fold lower, respectively. Woven scaffolds also supported adhesion and proliferation of mouse mesenchymal stem cells, and promoted biomineralization via alkaline phosphatase and mineral deposition. Finally, the scaffolds significantly enhanced the formation of new bone in damaged femoral condyle in rabbits. Thus, the scaffolds are potentially suitable for bone tissue engineering because of biomimetic architecture, excellent mechanical properties, and good biocompatibility. PMID:27287159

  7. Effect of surface modification of poly(lactic acid) by low-pressure ammonia plasma on adsorption of human serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Sarapirom, S. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayuthaya Road, Bangkok 10400 (Thailand); Boonyawan, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayuthaya Road, Bangkok 10400 (Thailand); Chaiwong, C., E-mail: cchwng@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayuthaya Road, Bangkok 10400 (Thailand)

    2014-08-15

    Highlights: • Poly(lactic acid) (PLA) films were treated by low-pressure ammonia plasma. • Human serum albumin (HSA) attachment on the treated PLA was reduced. • The treated PLA films were characterized. • Hydrophilicity enhancement due to polar groups introduced was the reason. • Reduced HSA adhesion could promote cell attachment on PLA for biomedicine. - Abstract: The final goal of the study was to promote understanding of mechanisms involved in cell attachment on biomedical polymer poly(lactic acid) (PLA). As the cell attachment on the material surface was preceded by blood protein adsorption which would critically affect subsequent cell adhesion, for the clinic application purpose, human serum albumin (HSA) was used in the investigation on its adsorption on PLA, which was however treated by low-pressure ammonia (NH{sub 3}) plasma. The NH{sub 3}-plasma-treated PLA was found to adsorb less HSA than the untreated PLA. The PLA was characterized using various techniques such as atomic force microscopy, contact angle and surface energy analysis and x-ray photoelectron spectroscopy. All of the characterization results indicated that due to NH{sub 3}-plasma-induced polar groups the PLA enhanced its hydrophilicity which in turn inhibited the HSA adsorption. The decreased HSA adsorption would consequently increase the cell attachment because of the cell adhesion barrier reduced.

  8. A biomimetic multilayer nanofiber fabric fabricated by electrospinning and textile technology from polylactic acid and Tussah silk fibroin as a scaffold for bone tissue engineering.

    Science.gov (United States)

    Shao, Weili; He, Jianxin; Han, Qiming; Sang, Feng; Wang, Qian; Chen, Li; Cui, Shizhong; Ding, Bin

    2016-10-01

    To engineer bone tissue, a scaffold with good biological properties should be provided to approximate the hierarchical structure of collagen fibrils in natural bone. In this study, we fabricated a novel scaffold consisting of multilayer nanofiber fabrics (MLNFFs) by weaving nanofiber yarns of polylactic acid (PLA) and Tussah silk fibroin (TSF). The yarns were fabricated by electrospinning, and we found that spinnability, as well as the mechanical properties of the resulting scaffold, was determined by the ratio between polylactic acid and Tussah silk fibroin. In particular, a 9:1 mixture can be spun continuously into nanofiber yarns with narrow diameter distribution and good mechanical properties. Accordingly, woven scaffolds based on this mixture had excellent mechanical properties, with Young's modulus 417.65MPa and tensile strength 180.36MPa. For nonwoven scaffolds fabricated from the same materials, the Young's modulus and tensile strength were 2- and 4-fold lower, respectively. Woven scaffolds also supported adhesion and proliferation of mouse mesenchymal stem cells, and promoted biomineralization via alkaline phosphatase and mineral deposition. Finally, the scaffolds significantly enhanced the formation of new bone in damaged femoral condyle in rabbits. Thus, the scaffolds are potentially suitable for bone tissue engineering because of biomimetic architecture, excellent mechanical properties, and good biocompatibility.

  9. Thermal characterization of the composites based on poly(lactic acid)

    OpenAIRE

    Srebrenkoska, Vineta; Bogoeva-Gaceva, Gordana

    2011-01-01

    In this study, rice-hulls-filled poly (lactic acid) (PLA) composites were prepared through addition of 5 wt. % PLA-grafted-MA (CA) for enhancement of adhesion between polymer matrix and natural filler. The composites containing 30% wt. rice hulls (RH) were prepared by compression molding. For the composites, the thermal properties were analyzed and compared to those of commonly used thermoplastic based-polymer, polypropylene (PP) containing the same reinforcement. Thermal stability of composi...

  10. Fade to Green: A Biodegradable Stack of Microbial Fuel Cells.

    Science.gov (United States)

    Winfield, Jonathan; Chambers, Lily D; Rossiter, Jonathan; Stinchcombe, Andrew; Walter, X Alexis; Greenman, John; Ieropoulos, Ioannis

    2015-08-24

    The focus of this study is the development of biodegradable microbial fuel cells (MFCs) able to produce useful power. Reactors with an 8 mL chamber volume were designed using all biodegradable products: polylactic acid for the frames, natural rubber as the cation-exchange membrane and egg-based, open-to-air cathodes coated with a lanolin gas diffusion layer. Forty MFCs were operated in various configurations. When fed with urine, the biodegradable stack was able to power appliances and was still operational after six months. One useful application for this truly sustainable MFC technology includes onboard power supplies for biodegradable robotic systems. After operation in remote ecological locations, these could degrade harmlessly into the surroundings to leave no trace when the mission is complete.

  11. Fade to Green: A Biodegradable Stack of Microbial Fuel Cells.

    Science.gov (United States)

    Winfield, Jonathan; Chambers, Lily D; Rossiter, Jonathan; Stinchcombe, Andrew; Walter, X Alexis; Greenman, John; Ieropoulos, Ioannis

    2015-08-24

    The focus of this study is the development of biodegradable microbial fuel cells (MFCs) able to produce useful power. Reactors with an 8 mL chamber volume were designed using all biodegradable products: polylactic acid for the frames, natural rubber as the cation-exchange membrane and egg-based, open-to-air cathodes coated with a lanolin gas diffusion layer. Forty MFCs were operated in various configurations. When fed with urine, the biodegradable stack was able to power appliances and was still operational after six months. One useful application for this truly sustainable MFC technology includes onboard power supplies for biodegradable robotic systems. After operation in remote ecological locations, these could degrade harmlessly into the surroundings to leave no trace when the mission is complete. PMID:26212495

  12. Miscibility and Morphology of Poly(lactic ACID)/POLY(Β-HYDROXYBUTYRATE) Blends

    Science.gov (United States)

    Tri Phuong, Nguyen; Guinault, Alain; Sollogoub, Cyrille

    2011-01-01

    The miscibility and morphology of poly(lactic)acid (PLA)/polyβ-hydroxybutyrate (PHB) prepared by melt blending method were investigated by Fourier transform infrared (FTIR), Differential scanning calorimetry (DSC), melt rheology and scanning electron microscopy (SEM) observations. FTIR and DSC methods present some limits to examine the miscibility state of PLA/PHB blends. This drawback can be overcome with the Cole-Cole method by observing the η" = f(η') curves to confirm the miscibility of semicrystalline PLA/ semicrystalline PHB blends. MEB micrographs of fractured surface of blends were also used to investigate the miscibility of these blends.

  13. Poly(lactic acid)/natural rubber/cellulose nanocrystal bionanocomposites part I. Processing and morphology.

    Science.gov (United States)

    Bitinis, Natacha; Verdejo, Raquel; Bras, Julien; Fortunati, Elena; Kenny, Jose Maria; Torre, Luigi; López-Manchado, Miguel Angel

    2013-07-25

    PLA/NR/cellulose nanowhisker composites were prepared using three types of cellulose nanocrystals (CNC), i.e. unmodified CNC obtained from acid hydrolysis of microcrystalline cellulose and two surface modified CNC. The two modification reactions, consisting on the grafting of long alkyl chains and of PLA chains onto the cellulose nanocrystals were carried out in order to facilitate the incorporation of the nanocrystals in the PLA/NR blend. A novel processing method was optimized combining solvent casting and extrusion in order to obtain a homogeneous dispersion of the nanofillers in the blend. The CNC modifications determined their location in the PLA/NR blend and influenced its morphology. PMID:23768607

  14. A novel basalt fiber-reinforced polylactic acid composite for hard tissue repair.

    Science.gov (United States)

    Chen, Xi; Li, Yan; Gu, Ning

    2010-08-01

    A basalt fiber (BF) was, for the first time, introduced into a poly(l-lactic acid) (PLLA) matrix as innovative reinforcement to fabricate composite materials for hard tissue repair. Firstly, BF/PLLA composites and pure PLLA were produced by the methods of solution blending and freeze drying. The results showed that basalt fibers can be uniformly dispersed in the PLLA matrix and significantly improve the mechanical properties and hydrophilicity of the PLLA matrix. The presence of basalt fibers may retard the polymer degradation rate and neutralize the acid degradation from PLLA. Osteoblasts were cultured in vitro to evaluate the cytocompatibility of the composite. An MTT assay revealed that osteoblasts proliferated well for 7 days and there was little difference found in their viability on both PLLA and BF/PLLA films, which was consistent with the alkaline phosphatase (ALP) activity results. A fluorescent staining observation showed that osteoblasts grew well on the composites. SEM images displayed that osteoblasts tended to grow along the fiber axis. The formation of mineralized nodules was observed on the films by Alizarin red S staining. These results suggest that the presence of basalt fibers does not noticeably affect osteoblastic behavior and the designed composites are osteoblast compatible. It is concluded that basalt fibers, as reinforcing fibers, may have promising applications in hard tissue repair.

  15. UTILIZATION OF MICRO SISAL FIBERS AS REINFORCEMENT AGENT AND POLYPROPYLENE OR POLYLACTIC ACID AS POLYMER MATRICES IN BIOCOMPOSITES MANUFACTURE

    Directory of Open Access Journals (Sweden)

    Subyakto Subyakto

    2013-06-01

    Full Text Available Sisal (Agave sisalana as a perennial tropical plant grows abundantly in Indonesia. Its fibers can be used as the reinforcement agent of biocomposite products. Utilization of sisal as natural fiber has some notable benefits compared to synthetic fibers, such as renewable, light in weight, and low in cost. Manufacture of biocomposite requires the use of matrix such as thermoplastic polymer, e.g. polypropylene (PP and polylactic acid (PLA to bond together with the reinforcement agent (e.g. sisal fibers. In relevant, experiment was conducted on biocomposites manufacture that comprised sisal fibers and PP as well as PLA. Sisal fibers were converted into pulp, then refined to micro-size fibrillated fibers such that their diameter reduced to about 10 μm, and dried in an oven. The dry microfibrillated sisal pulp fibers cellulose (MSFC were thoroughly mixed with either PP or PLA with varying ratios of MSFC/PP as well as MSFC/PLA, and then shaped into the mat (i.e. MSFC-PP and MSFC-PLA biocomposites. Two kinds of shaping was employed, i.e. hot-press molding and injection molding. In the hot-press molding, the ratio of  MSFC/PP as well as MSFC/PLA ranged about 30/70-50/50. Meanwhile in the injection (employed only on assembling the MSFC-PLA biocomposite, the ratio of MSFC/PLA varied about 10/90-30/70. The resulting shaped MSFC-PP and MSFC-PLA biocomposites were then tested of its physical and mechanical properties. With the hot-press molding device, the physical and mechanical (strength properties of MSFC-PLA biocomposite were higher than those of  MSFC-PP biocomposite. The optimum ratio of  MSFC/PP as well as MSFC/PLA reached concurrently at 40/60. The strengths of MSFC-PP as well as MSFC-PLA biocomposites were greater than those of individual polymer (PP and PLA. With the injection molding device, only the MSFC-PLA  biocomposite  was formed  and its strengths  reached  maximum  at 30/70  ratio.  The particular strengths (MOR and MOE of MSFC

  16. Chitosan coated polylactic acid nanoparticle-mediated combinatorial delivery of cisplatin and siRNA/Plasmid DNA chemosensitizes cisplatin-resistant human ovarian cancer cells.

    Science.gov (United States)

    Babu, Anish; Wang, Qi; Muralidharan, Ranganayaki; Shanker, Manish; Munshi, Anupama; Ramesh, Rajagopal

    2014-08-01

    Development of resistance toward anticancer drugs results in ineffective therapy leading to increased mortality. Therefore, overriding resistance and restoring sensitivity to anticancer drugs will improve treatment efficacy and reduce mortality. While numerous mechanisms for drug resistance in cancer have previously been demonstrated, recent studies implicate a role for proteasome and the autophagy regulatory protein P62/SQSTM1 (P62) in contributing to drug resistance. Specifically, reduction in the expression of the β5 subunit of the proteasome and/or enhanced P62 protein expression is known to contribute to cancer drug resistance such as cisplatin (CDDP) in ovarian cancer cells. Therefore, we hypothesized that restoration of β5 expression and/or suppression of P62 protein expression in CDDP-resistant ovarian cancer cells will lead to restoration of sensitivity to CDDP and enhanced cell killing. To test our hypothesis we developed a biodegradable multifunctional nanoparticle (MNP) system that codelivered P62siRNA, β5 plasmid DNA, and CDDP and tested its efficacy in CDDP resistant 2008/C13 ovarian cancer cells. MNP consisted of CDDP loaded polylactic acid nanoparticle as inner core and cationic chitosan (CS) consisting of ionically linked P62siRNA (siP62) and/or β5 expressing plasmid DNA (pβ5) as the outer layer. The MNPs were spherical in shape with a hydrodynamic diameter in the range of 280-350 nm, and demonstrated encapsulation efficiencies of 82% and 78.5% for CDDP and siRNA respectively. MNPs efficiently protected the siRNA and showed superior serum stability compared to naked siRNA as measured by gel retardation and spectrophotometry assays. The MNPs successfully delivered siP62 and pβ5 to cause P62 knockdown and restoration of β5 expression in 2008/C13 cells. Combined delivery of siP62, pβ5, and CDDP using the MNPs resulted in a marked reduction in the IC50 value of CDDP in 2008/C13 cells from 125 ± 1.3 μM to 98 ± 0.6 μM (P < 0.05; 21

  17. Chitosan coated polylactic acid nanoparticle-mediated combinatorial delivery of cisplatin and siRNA/Plasmid DNA chemosensitizes cisplatin-resistant human ovarian cancer cells.

    Science.gov (United States)

    Babu, Anish; Wang, Qi; Muralidharan, Ranganayaki; Shanker, Manish; Munshi, Anupama; Ramesh, Rajagopal

    2014-08-01

    Development of resistance toward anticancer drugs results in ineffective therapy leading to increased mortality. Therefore, overriding resistance and restoring sensitivity to anticancer drugs will improve treatment efficacy and reduce mortality. While numerous mechanisms for drug resistance in cancer have previously been demonstrated, recent studies implicate a role for proteasome and the autophagy regulatory protein P62/SQSTM1 (P62) in contributing to drug resistance. Specifically, reduction in the expression of the β5 subunit of the proteasome and/or enhanced P62 protein expression is known to contribute to cancer drug resistance such as cisplatin (CDDP) in ovarian cancer cells. Therefore, we hypothesized that restoration of β5 expression and/or suppression of P62 protein expression in CDDP-resistant ovarian cancer cells will lead to restoration of sensitivity to CDDP and enhanced cell killing. To test our hypothesis we developed a biodegradable multifunctional nanoparticle (MNP) system that codelivered P62siRNA, β5 plasmid DNA, and CDDP and tested its efficacy in CDDP resistant 2008/C13 ovarian cancer cells. MNP consisted of CDDP loaded polylactic acid nanoparticle as inner core and cationic chitosan (CS) consisting of ionically linked P62siRNA (siP62) and/or β5 expressing plasmid DNA (pβ5) as the outer layer. The MNPs were spherical in shape with a hydrodynamic diameter in the range of 280-350 nm, and demonstrated encapsulation efficiencies of 82% and 78.5% for CDDP and siRNA respectively. MNPs efficiently protected the siRNA and showed superior serum stability compared to naked siRNA as measured by gel retardation and spectrophotometry assays. The MNPs successfully delivered siP62 and pβ5 to cause P62 knockdown and restoration of β5 expression in 2008/C13 cells. Combined delivery of siP62, pβ5, and CDDP using the MNPs resulted in a marked reduction in the IC50 value of CDDP in 2008/C13 cells from 125 ± 1.3 μM to 98 ± 0.6 μM (P < 0.05; 21

  18. Biodegradation of New Polymer Foundry Binders for the Example of the Composition Polyacrylic Acid/Starch

    Directory of Open Access Journals (Sweden)

    Beata Grabowska

    2011-04-01

    Full Text Available The investigations on the biodegradation process pathway of the new polymer binders for the example of water soluble compositionpolyacrylic acid/starch are presented in the hereby paper. Degradation was carried out in water environment and in a soil. Thedetermination of the total oxidation biodegradation in water environment was performed under laboratory conditions in accordance with the static water test system (Zahn-Wellens method, in which the mixture undergoing biodecomposition contained inorganic nutrient,activated sludge and the polymer composition, as the only carbon and energy source. The biodecomposition progress of the polymercomposition sample in water environment was estimated on the basis of the chemical oxygen demand (COD measurements and thedetermination the biodegradation degree, Rt, during the test. These investigations indicated that the composition polyacrylic acid/starchconstitutes the fully biodegradable material in water environment. The biodegradation degree Rt determined in the last 29th day of the test duration achieved 65%, which means that the investigated polymer composition can be considered to be fully biodegradable.During the 6 months biodegradation process of the cross-linked sample of the polymer composition in a garden soil several analysis ofsurface and structural changes, resulting from the sample decomposition, were performed. Those were: thermal analyses (TG-DSC,structural analyses (Raman spectroscopy and microscopic analyses (optical microscopy, AFM.

  19. Morphology and thermal degradation study of poly(lactic acid)/synthetic mica composites; Estudo da morfologia e da degradacao termica de compositos de poli(acido latico)/mica sintetica organofilica

    Energy Technology Data Exchange (ETDEWEB)

    Souza, D.H.S.; Dias, M.L., E-mail: diegosaboya@ima.ufrj.b [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Professora Eloisa Mano

    2010-07-01

    Poly(lactic acid) (PLA)/synthetic mica composites has been little studied in the literature. In this work, an organophilic synthetic mica was used to prepare PLA nanocomposites. The composites were obtained at an internal mixer containing 3, 5, 7 and 10 wt% of mica. The materials were analyzed by x-ray diffraction, thermogravimetric analysis and gel permeation chromatography. (author)

  20. Quantitative structure-activity relationship study on the biodegradation of acid dyestuffs

    Institute of Scientific and Technical Information of China (English)

    LI Yin; XI Dan-li

    2007-01-01

    Quantitative structure-biodegradability relationships (QSBRs) were established to develop predictive models and mechanistic explanations for acid dyestuffs as well as biological activities. With a total of four descriptors, molecular weight (MW), energies of the highest occupied molecular orbital (EHOMO), the lowest unoccupied molecular orbital (ELUMO), and the excited state (EES), calculated using quantum chemical semi-empirical methodology, a series of models were analyzed between the dye biodegradability and each descriptor. Results showed that EHOMO and MW were the dominant parameters controlling the biodegradability of acid dyes. A statistically robust QSBR model was developed for all studied dyes, with the combined application of EHOMO and MW. The calculated biodegradations fitted well with the experimental data monitored in a facultative-aerobic process, indicative of the reliable prediction and mechanistic character of the developed model.

  1. Synergistic Effects of Nucleating Agents and Plasticizers on the Crystallization Behavior of Poly(lactic acid

    Directory of Open Access Journals (Sweden)

    Xuetao Shi

    2015-01-01

    Full Text Available The synergistic effect of nucleating agents and plasticizers on the thermal and mechanical performance of PLA nanocomposites was investigated with the objective of increasing the crystallinity and balancing the stiffness and toughness of PLA mechanical properties. Calcium carbonate, halloysite nanotubes, talc and LAK (sulfates were compared with each other as heterogeneous nucleating agents. Both the DSC isothermal and non-isothermal studies indicated that talc and LAK were the more effective nucleating agents among the selected fillers. Poly(D-lactic acid (PDLA acted also as a nucleating agent due to the formation of the PLA stereocomplex. The half crystallization time was reduced by the addition of talc to about 2 min from 37.5 min of pure PLA by the isothermal crystallization study. The dynamic mechanical thermal study (DMTA indicated that nanofillers acted as both reinforcement fillers and nucleating agents in relation to the higher storage modulus. The plasticized PLA studied by DMTA indicated a decreasing glass transition temperature with the increasing of the PEG content. The addition of nanofiller increased the Young’s modulus. PEG had the plasticization effect of increasing the break deformation, while sharply decreasing the stiffness and strength of PLA. The synergistic effect of nanofillers and plasticizer achieved the balance between stiffness and toughness with well-controlled crystallization.

  2. Continuous biodegradation of sulfanilic acid in a multi-stage packed bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Salazar-Huerta, A.; Velazquez-Garcia, A.; Cobos-Vasconcelos, D. de los.; Juarez-Ramirez, C.; Ruiz-Ordaz, N.; Galindez-Mayer, J.

    2009-07-01

    Sulfanilic acid SA is an aromatic amine derived from the azo-bond cleavage of several textile dyes. Recalcitrance and toxicity of this amine is high, and with frequency it could be found as an aquatic contaminant; thus biodegradation process for its removal are justified. Although the SA molecule contains carbon, nitrogen and sulphur, its C:N:S proportion is unbalanced for microbial growth in a biodegradation process; thus nutrient complementation should be necessary for its complete removal. (Author)

  3. Synthesis, characterization and biocompatibility evaluation of hydroxyapatite - gelatin polyLactic acid ternary nanocomposite

    Directory of Open Access Journals (Sweden)

    Z. Nabipour

    2016-04-01

    Full Text Available Objective(s: The current study reports the production and biocompatibility evaluation of a ternary nanocomposite consisting of HA, PLA, and gelatin for biomedical application.Materials and Methods: Hydroxyapatite nanopowder (HA: Ca10(PO46(OH2 was produced by burning the bovine cortical bone within the temperature range of 350-450 oC followed by heating in an oven at 800. Synthesis of the ternary nanocomposite was carried out in two steps: synthesis of gelatin-hydroxyapatite binary nanocomposite and addition of poly lactic acid with different percentages to the resulting composition. The crystal structure was determined by X-ray diffraction (XRD, while major elements and impurities of hydroxyapatite were identified by elemental analysis of X-ray fluorescence (XRF. Functional groups were determined by Fourier transform infrared spectroscopy (FTIR. Morphology and size of the nanocomposites were evaluated using field emission scanning electron microscope (FE-SEM.Biocompatibility of nanocomposites was investigated by MTT assay. Results: XRD patterns verified the ideal crystal structure of the hydroxyapatite, which indicated an appropriate synthesis process and absence of disturbing phases. Results of FTIR analysis determined the polymers’ functional groups, specified formation of the polymers on the hydroxyapatite surface, and verified synthesis of nHA/PLA/Gel composite. FESEM images also indicated the homogeneous structure of the composite in the range of 50 nanometers. MTT assay results confirmed the biocompatibility of nanocomposite samples.Conclusion: This study suggested that the ternary nanocomposite of nHA/PLA/Gel can be a good candidate for biomedical application such as drug delivery systems, but for evaluation of its potential in hard tissue replacement, mechanical tests should be performed.

  4. Transparent nanocellulosic multilayer thin films on polylactic acid with tunable gas barrier properties.

    Science.gov (United States)

    Aulin, Christian; Karabulut, Erdem; Tran, Amy; Wågberg, Lars; Lindström, Tom

    2013-08-14

    The layer-by-layer (LbL) deposition method was used for the build-up of alternating layers of nanofibrillated cellulose (NFC) or carboxymethyl cellulose (CMC) with a branched, cationic polyelectrolyte, polyethyleneimine (PEI) on flexible poly (lactic acid) (PLA) substrates. With this procedure, optically transparent nanocellulosic films with tunable gas barrier properties were formed. 50 layer pairs of PEI/NFC and PEI/CMC deposited on PLA have oxygen permeabilities of 0.34 and 0.71 cm(3)·μm/m(2)·day·kPa at 23 °C and 50% relative humidity, respectively, which is in the same range as polyvinyl alcohol and ethylene vinyl alcohol. The oxygen permeability of these multilayer nanocomposites outperforms those of pure NFC films prepared by solvent-casting. The nanocellulosic LbL assemblies on PLA substrates was in detailed characterized using a quartz crystal microbalance with dissipation (QCM-D). Atomic force microscopy (AFM) reveals large structural differences between the PEI/NFC and the PEI/CMC assemblies, with the PEI/NFC assembly showing a highly entangled network of nanofibrils, whereas the PEI/CMC surfaces lacked structural features. Scanning electron microscopy images showed a nearly perfect uniformity of the nanocellulosic coatings on PLA, and light transmittance results revealed remarkable transparency of the LbL-coated PLA films. The present work demonstrates the first ever LbL films based on high aspect ratio, water-dispersible nanofibrillated cellulose, and water-soluble carboxymethyl cellulose polymers that can be used as multifunctional films and coatings with tailorable properties, such as gas barriers and transparency. Owing to its flexibility, transparency and high-performance gas barrier properties, these thin film assemblies are promising candidates for several large-scale applications, including flexible electronics and renewable packaging. PMID:23834391

  5. PREPARATION AND PROPERTIES OF POLY (LACTIC ACID-CO-GLYCOL TEREPHTHALIC ACID) COPOLYESTER

    Institute of Scientific and Technical Information of China (English)

    GAO Cuili; JI Quan; KONG Qingshan; XIA Yanzhi

    2006-01-01

    To obtain a kind of biodegradable polymer material with satisfactory properties, a new biodegradable copolyester poly(lactic acid-co-glycol terephthalate) (PETA), was synthesized from three monomers of lactic acid, glycol and terephthalic acid. The resulting copolyesters, PETA, were characterized by FT-IR, 1H-NMR, DSC, TGA and by the ways of weight loss rate to characterize their biodegradability. The findings in this work indicated that, the TmS and TdS of copolyesters PETA increased with increasing contents of the terephthalic acid units. From the biodegradation tests in natural soil, boiling water, acid buffer solution and alkali buffer solution, it was shown that the biodegradability of copolyesters PETA decreased with increasing contents of the terephthalic acid units.

  6. The embolization effect of tanshinone II A-polylactic acid/glycolic acid microspheres on the hepatic artery in experimental rabbits

    International Nuclear Information System (INIS)

    Objective: To observe the embolization effect of tanshinone II A-polylactic acid/glycolic acid microspheres (PLGA) on the hepatic artery in experimental rabbits. Methods: Under DSA guidance, hepatic catheterization and angiography was performed in 24 New Zealand white rabbits. Via the catheter tanshinone II A-PLGA microspheres was injected into the hepatic arteries. Each time at 10 minutes and on the 1 st, 3 rd, 7 th, 14 th, 21 st, 30 th and 42 nd day after the treatment, every three rabbits were randomly selected for the re-examination with angiography to observe the embolization state of the hepatic arteries, then the animals were sacrificed and the liver, heart, spleen, lung kidney and stomach were removed and sent for pathologic exam. Simultaneously, the functional tests of liver and kidney as well as the routine blood tests were made. The results were evaluated. Results: The peripheral micro-vessels of the hepatic artery vanished away at 10 minutes after embolization, and they remained un-visualized till the 30th day after embolization. On the 42nd day after embolization the peripheral micro-vessels of the hepatic artery could be visualized again. Pathologically,signs of inflammation and necrosis appeared in the occluded areas. Blood biochemical examination showed that there was a transient elevation of white blood cells after the procedure, which fell to normal level on the 7th day (P > 0.05). Both AST and ALT reached their peaks on the 3rd day, then they decreased gradually and returned to normal on the 7th day (P > 0.05). Conclusion: Tanshinone II A-PLGA microspheres have better embolization effect on the hepatic arteries, this effect lasts for 30 to 42 days. Therefore, tanshinone II A-PLGA microsphere is an ideal embolization agent for the treatment of neoplasm. (authors)

  7. Quantitative analysis of mechanical and electrostatic properties of poly(lactic) acid fibers and poly(lactic) acid—carbon nanotube composites using atomic force microscopy

    Science.gov (United States)

    Iqbal, Qais; Bernstein, Peter; Zhu, Yazhe; Rahamim, Joseph; Cebe, Peggy; Staii, Cristian

    2015-03-01

    We use atomic force microscopy (AFM) to perform a systematic quantitative characterization of the elastic modulus and dielectric constant of poly(L-lactic acid) electrospun nanofibers (PLLA), as well as composites of PLLA fibers with 1.0 wt% embedded multiwall carbon nanotubes (MWCNTs-PLLA). The elastic moduli are measured in the fiber skin region via AFM nanoindentation, and the dielectric constants are determined by measuring the phase shifts obtained via electrostatic force microscopy (EFM). We find that the average value for the elastic modulus for PLLA fibers is (9.8 ± 0.9) GPa, which is a factor of 2 larger than the measured average elastic modulus for MWCNT-PLLA composites (4.1 ± 0.7) GPa. We also use EFM to measure dielectric constants for both types of fibers. These measurements show that the dielectric constants of the MWCNT-PLLA fibers are significantly larger than the corresponding values obtained for PLLA fiber. This result is consistent with the higher polarizability of the MWCNT-PLLA composites. The measurement methods presented are general, and can be applied to determine the mechanical and electrical properties of other polymers and polymer nanocomposites.

  8. Quantitative analysis of mechanical and electrostatic properties of poly(lactic) acid fibers and poly(lactic) acid—carbon nanotube composites using atomic force microscopy

    International Nuclear Information System (INIS)

    We use atomic force microscopy (AFM) to perform a systematic quantitative characterization of the elastic modulus and dielectric constant of poly(L-lactic acid) electrospun nanofibers (PLLA), as well as composites of PLLA fibers with 1.0 wt% embedded multiwall carbon nanotubes (MWCNTs–PLLA). The elastic moduli are measured in the fiber skin region via AFM nanoindentation, and the dielectric constants are determined by measuring the phase shifts obtained via electrostatic force microscopy (EFM). We find that the average value for the elastic modulus for PLLA fibers is (9.8 ± 0.9) GPa, which is a factor of 2 larger than the measured average elastic modulus for MWCNT–PLLA composites (4.1 ± 0.7) GPa. We also use EFM to measure dielectric constants for both types of fibers. These measurements show that the dielectric constants of the MWCNT–PLLA fibers are significantly larger than the corresponding values obtained for PLLA fiber. This result is consistent with the higher polarizability of the MWCNT–PLLA composites. The measurement methods presented are general, and can be applied to determine the mechanical and electrical properties of other polymers and polymer nanocomposites. (paper)

  9. 生态友好材料聚乳酸的合成研究进展%Recent Advances in Synthesis of Eco-friendly Polymers Based on Polylactic Acid

    Institute of Scientific and Technical Information of China (English)

    黄伟; 李弘; 张全兴

    2012-01-01

    Synthesis and application of polylactic acid (PLA), a kind of eco-friendly polymers possessing excellent biocompatibility and biodegradability, has recently attracted greatly attention. PLA is manufactured by two methods, i. e. polycondensation and ring-opening. Commercially the catalysts used for the synthesis of PLA are stannous compounds as stannous chloride dehydrate, and stannous octoate. Research revealed that the stannous compounds are cytotoxic that has aroused concern about the bio-safety of the materials based on PLA and its use in humans. Key advances in synthesis of PLA were reviewed.%聚乳酸(PLA)是一种具有高度生物相容性、生物可降解性的环境友好型材料,其合成方法及应用研究日益受到关注。聚乳酸的合成主要有两种方法:缩聚和开环。商品化聚乳酸合成中所使用的催化剂主要为锡类化合物,例如二水合氯化亚锡和辛酸亚锡。研究表明锡类化合物具有一定的生理毒性,因而引起了人们对聚乳酸材料的生物安全性以及其在人体中使用的关注。本文综述了近年在生物降解性聚乳酸类材料的合成方面的重要研究进展。

  10. Biodegradability of terephthalic acid in terylene artificial silk printing and dyeing wastewater

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    As the characteristic pollutant, terephthalic acid(TA)was in charge of 40%-78% of the total COD of terylene artificial silk printing and dyeing wastewater(TPW-water). The studies on biodegradability of TA were conducted in a serial of activated sludge reactors with TPW-water. TA appeared to be readily biodegradable with removal efficiency over 96.5% under aerobic conditions, hardly biodegradable with removal efficiency below 10% under anoxic conditions and slowly biodegradable with a turnover between 31.4% and 56.0% under anaerobic conditions. TA also accounted for the majority of BOD in TPW-water. The process combined by anoxic, anaerobic and aerobic activated sludge reactor was suitable for TA degradation and TPW-water treatment. Further, the aerobic process was essentially much more effective than the anaerobic or anoxic one to degrade TA in TPW-water.

  11. The toxicity of rifampicin polylactic acid nanoparticles against Mycobacterium bovis BCG and human macrophage THP-1 cell line

    Science.gov (United States)

    Erokhina, M.; Rybalkina, E.; Barsegyan, G.; Onishchenko, G.; Lepekha, L.

    2015-11-01

    Tuberculosis is rapidly becoming a major health problem. The rise in tuberculosis incidence stimulates efforts to develop more effective delivery systems for the existing antituberculous drugs while decreasing the side effects. The nanotechnology may provide novel drug delivery tools allowing controlled drug release. Rifampicin is one of the main antituberculous drugs, characterized by high toxicity, and Poly (L-lactic acid) (PLLA) is a biodegradable polymer used for the preparation of encapsulated drugs. The aim of our work was to evaluate the toxicity of rifampicin-PLLA nanoparticles against Mycobacterium bovis BCG using human macrophage THP-1 cell line. Our data demonstrate that rifampicin-PLLA is effective against M. bovis BCG in the infected macrophages. The drug is inducing the dysfunction of mitochondria and apoptosis in the macrophages and is acting as a potential substrate of Pgp thereby modulating cell chemosensitivity. The severity of the toxic effects of the rifampicin-PLLA nanoparticles is increasing in a dose-dependent manner. We suggest that free rifampicin induces death of M. bovis BCG after PLLA degradation and diffusion from phago-lysosomes to cytoplasm causing mitochondria dysfunction and affecting the Pgp activity.

  12. Production and characterization of thermoplastic cassava starch, functionalized poly(lactic acid), and their reactive compatibilized blends

    Science.gov (United States)

    Detyothin, Sukeewan

    Cassava starch was blended with glycerol using a co-rotating twin-screw extruder (TSE). Thermoplastic cassava starch (TPCS) at a ratio of 70/30 by weight of cassava/glycerol was selected and further blended with other polymers. TPCS sheets made from compression molding had low tensile strength (0.45 +/- 0.05 MPa) and Young's modulus (1.24 +/- 0.58 MPa), but moderate elongation at break (83.0 +/- 0.18.6%), medium level of oxygen permeability, and high water vapor permeability with a very high rate of water absorption. TPCS was blended with poly(lactic acid) (PLA) at various ratios by using a TSE. The blend resins exhibited good properties such as increased thermal stability (Tmax) and crystallinity of PLA, and improved water sensitivity and processability of TPCS. PLA and TPCS exhibited a high interfacial tension between the two phases of 7.9 mJ·m -2, indicating the formation of an incompatible, immiscible blend. SEM micrographs showed a non-homogeneous distribution of TPCS droplets in the PLA continuous phase. TEM micrographs of the blend films made by cast-film extrusion showed coalescence of the TPCS droplets in the PLA continuous phase of the blend, indicating that the compatibility between the polymer pair needs to be improved. A response surface methodology (RSM) design was used to analyze the effects of maleic anhydride (MA) and 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (Luperox or L101) contents, and TSE screw speed on the degree of grafted MA and number average molecular weight (Mn) of functionalized PLA (PLA-g-MA), a reactive compatibilizer. PLA-g- MA made by reactive extrusion had an array of colors depending on the content of L101 and MA used. New FTIR peaks suggested that MA was grafted onto the PLA backbone and oligomeric MA may occur. Increasing L101 increased the degree of grafting and decreased Mn, but the Mn of the PLA-g-MA's produced with a high amount of L101 was stable during storage. MA exhibited an optimum concentration for maximizing the

  13. Poly(lactic acid-co-glycolic acid)-poly(ethylene glycol)-poly(lactic acid-co-glycolic acid) thermogel as a novel submucosal cushion for endoscopic submucosal dissection.

    Science.gov (United States)

    Yu, Lin; Xu, Wei; Shen, Wenjia; Cao, Luping; Liu, Yan; Li, Zhaoshen; Ding, Jiandong

    2014-03-01

    Endoscopic submucosal dissection (ESD) is a clinical therapy for early stage neoplastic lesions in the gastrointestinal tract. It is, however, faced with a crucial problem: the high occurrence of perforation. The formation of a submucosal fluid cushion (SFC) via a fluid injection is the best way to avoid perforation, and thus an appropriate biomaterial is vital for this minimally invasive endoscopic technique. In this study, we introduced an injectable thermogel as a novel submucosal injection substance in ESD. The hydrogel synthesized by us was composed of poly(lactic acid-co-glycolic acid)-poly(ethylene glycol)-poly(lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) triblock copolymers. The polymer/water system was a low-viscosity fluid at room temperature and thus easily injected, and turned into a non-flowing gel at body temperature after injection. The submucosal injection of the thermogel to create SFCs was performed in both resected porcine stomachs and living minipigs. High mucosal elevation with a clear margin was maintained for a long duration. Accurate en bloc resection was achieved with the assistance of the thermogel. The mean procedure time was strikingly reduced. Meanwhile, no obvious bleeding, perforation and tissue damage were observed. The application of the thermogel not only facilitated the ESD procedure, but also increased the efficacy and safety of ESD. Therefore, the PLGA-PEG-PLGA thermogel provides an excellent submucosal injection system, and has great potential to improve the ESD technique significantly.

  14. Preparation and characterization of reactive blends of poly(lactic acid), poly(ethylene-co-vinyl alcohol), and poly(ethylene-co-glycidyl methacrylate)

    Energy Technology Data Exchange (ETDEWEB)

    Warangkhana, Phromma; Rathanawan, Magaraphan, E-mail: rathanawan.k@chula.ac.th [Chulalongkorn University, Petroleum and Petrochemical College - Bangkok (Thailand); Jana Sadhan, C., E-mail: janas@uakron.edu [The University of Akron, Department of Polymer Engineering, Ohio (United States)

    2015-05-22

    The ternary blends of poly(lactic acid) (PLA), poly(ethylene-co-vinyl alcohol) (EVOH), and poly(ethylene-co-glycidyl methacrylate) (EGMA) were prepared. The role of EGMA as a compatibilizer was evaluated. The weight ratio of PLA:EVOH was 80:20 and the EGMA loadings were varied from 5-20 phr. The blends were characterized as follows: thermal properties by differential scanning calorimetry, morphology by scanning electron microscopy, and mechanical properties by pendulum impact tester, and universal testing machine. The glass transition temperature of PLA blends did not change much when compared with that of PLA. The blends of PLA/EGMA and EVOH/EGMA showed EGMA dispersed droplets where the latter led to poor impact properties. However, the tensile elongation at break and tensile toughness substantially increased upon addition of EGMA to blends of PLA and EVOH. It was noted in tensile test samples that both PLA and EVOH domains fibrillated significantly to produce toughness.

  15. Graphene Oxide and Gadolinium-Chelate Functionalized Poly(lactic acid) Nanocapsules Encapsulating Perfluorooctylbromide for Ultrasound/Magnetic Resonance Bimodal Imaging Guided Photothermal Ablation of Cancer.

    Science.gov (United States)

    Li, Zhenglin; Ke, Hengte; Wang, Jinrui; Miao, Zhaohua; Yue, Xiuli

    2016-03-01

    This paper successfully fabricated a novel multifunctional theranostic agent (PFOB@PLA/GO/Gd-DTPA NCs) by loading perfluorooctylbromide (PFOB) into poly(lactic acid) (PLA) nanocapsules (NCs) followed by surface functionalization with graphene oxide (GO) and gadolinium-chelate (Gd-DTPA). It was found that the resulting nanoagent could serve as a contrast agent simultaneously to enhance ultrasound (US) and magnetic resonance imaging (MRI). Benefiting from the strong absorption in the near infrared (NIR) region, the nanocapsules could efficiently kill cancer cells under NIR laser irradiation. Thus, such a single theranostic agent with the combination of realtime US imaging and high-resolution MR imaging could achieve great therapeutic effectiveness without systemic damage to the body. In addition, the cytotoxicity assay on HUVEC cells revealed a good biocompatibility of PFOB@PLA/GO/Gd-DTPA NCs, showing that the versatile nanocapsule system may hold great potential as an effective nanoplatform for contrast enhanced imaging guided photothermal therapy.

  16. Effects of SEBS-g-MAH on the properties of injection moulded poly(lactic acid/nano-calcium carbonate composites

    Directory of Open Access Journals (Sweden)

    W. S. Chow

    2012-06-01

    Full Text Available Poly(lactic acid/nano-precipitated calcium carbonate (PLA/NPCC composites toughened with maleated styrene-ethylene/butylene-styrene (SEBS-g-MAH were prepared by melt-compounding on a co-rotating twin-screw extruder followed by injection moulding. The mechanical properties of the PLA nanocomposites were characterized by tensile, flexural and impact tests, while their morphology were investigated using transmission electron microscopy (TEM. The thermal properties of the composites were examined with differential scanning calorimeter (DSC and thermogravimetric analyzer (TGA. The elongation at break and impact strength of the PLA/NPCC nanocomposites increased significantly after addition of SEBS-g-MAH. Both nano-dispersed NPCC and small NPCC clusters were found in PLA matrix. Also, some SEBS-g-MAH encapsulated NPCC can be observed. Thermal stability of PLA/NPCC was enhanced prominently by the addition of SEBS-g-MAH.

  17. Preparation of hydrophilic poly(lactic acid) tissue engineering scaffold via (PLA)-(PLA-b-PEG)-(PEG) solution casting and thermal-induced surface structural transformation.

    Science.gov (United States)

    Zhu, Xiaomin; Zhong, Tian; Huang, Ran; Wan, Ajun

    2015-01-01

    Porous poly(lactic acid) (PLA) tissue engineering scaffolds with a hydrophilic surface assembled by polyethylene glycol aggregations were prepared by the solvent casting/particulate leaching method from (PLA)-(PLA-b-PEG)-(PEG) blend solution, where the PLA-b-PEG block polymer serves as an amphiphilic glue between two phases. A thermal recrystallization process was inserted before leaching to induce a phase separation, which subsequently squeezes out PEG to form a hydrophilic shell. Characterizations of XRD and DSC indicated the composition and mixing states of materials. The water contact angle test qualitatively presented the excellent hydrophilicity compared to the pure PLA or PLA-PEG simple blend scaffold. The scanning electron microscope results confirmed the formation of porous structure of [Formula: see text] pore size, with an observable phase separation on the surface. The scaffold was degraded in PBS at [Formula: see text], and the degradation exhibits a three-stage behavior, which evidenced the amphiphilically glued phase separations.

  18. Effect of Extrusion on the Mechanical and Rheological Properties of a Reinforced Poly(Lactic Acid: Reprocessing and Recycling of Biobased Materials

    Directory of Open Access Journals (Sweden)

    Víctor Peinado

    2015-10-01

    Full Text Available The aim of this research paper is to study the behaviour of a common used biopolymer (Poly(Lactic Acid (PLA after several reprocesses and how two different types of additives (a melt strength enhancer and a nanoadditive affect its mechanical and rheological properties. Systematic extraction of extrudate samples from a twin-screw compounder was done in order to study the effect in the properties of the reprocessed material. Detailed rheological tests on a capillary rheometer as well as mechanical studies on a universal tensile machine after preparation of injected specimens were carried out. Results evidenced that PLA and reinforced PLA materials can be reprocessed and recycled without a remarkable loss in their mechanical properties. Several processing restrictions and specific phenomena were identified and are explained in the present manuscript.

  19. A Simple-to-Implement Simulator for the Reactive Extrusion of Poly(Lactic Acid in a Corotating Uniform Twin-Screw Extruder

    Directory of Open Access Journals (Sweden)

    René O. Vargas

    2015-01-01

    Full Text Available The present paper deals with the poly(lactic acid (PLA reactive processing simulation in a uniform corotating twin-screw extruder that can be readily turned into practical applications in pilot and industrial equipment. The simulator provides a cause-effect guide that can be useful for starting an experimental setup in a reactive screw extruder for a biopolymer in a growing industry. The proposed model considers a free radical ring-opening mechanism involving the main characteristic flows inside the extruder and the non-Newtonian behavior of PLA. The characteristic behavior relating reaction rate, average molecular weights, and polydispersity against chamber number are described by S-shaped and monotonically decreasing curves, for the equipment. Numerical predictions show that this simple and easy to implement model accurately reproduces previously reported data and that the impurity concentration exhibits a marked effect over all the variables, except conversion.

  20. Fabrication of long-acting drug release property of hierarchical porous bioglasses/polylactic acid fibre scaffolds for bone tissue engineering.

    Science.gov (United States)

    Wang, Dan; Lin, Huiming; Jiang, Jingjie; Jin, Qumei; Li, Lei; Dong, Yan; Qu, Fengyu

    2015-04-01

    Hierarchical porous fibre scaffolds with mesoporous bioglasses (MBGs) and polylactic acid (PLA) were successfully fabricated by the electrospinning method. These compound scaffolds possess macropores with sizes of about 100 nm because of the solvent evaporation from the fibre and the mesoporous structure ( ∼4.0 nm) originated from MBGs. The biomineralisation ability was investigated in simulated body fluid. The fibre structure is beneficial for inducing the growth of hydroxyapatite. In addition, compared with pure MBGs, the materials (MP-1 and MP-2) exhibit a long-acting drug release process up to 140 h and the drug release process corresponds with the Fickian diffusion mechanism. With the special fibre morphology and the hierarchical porous structure, the MBGs/PLA fibre scaffolds are expected to have potential application for bone tissue repair and regeneration.

  1. 聚乳酸的制备及应用研究进展%Advances in the Research of Production and Application of Polylactic Acid

    Institute of Scientific and Technical Information of China (English)

    林季; 颜光涛

    2005-01-01

    聚乳酸(polylactic acid,PLA)是以乳酸为单体经化学合成的新型生物降解性高分子材料.它具有无毒、无刺激性及生物相容性良好的特点,可经生物分解为CO2和H2O,不造成环境污染.目前,已有多种方法制备乳酸和聚乳酸,并广泛应用于生物医学、工业、农业及日常生活等领域.

  2. Polylactic acid-nanocrystalline carbonated hydroxyapatite (PLA-cHAP) composite: preparation and surface topographical structuring with direct laser writing (DLW)

    CERN Document Server

    Garskaite, Edita; Drienovsky, Marian; Krajcovic, Jozef; Cicka, Roman; Palcut, Marian; Jonusauskas, Linas; Malinauskas, Mangirdas; Stankeviciute, Zivile; Kareiva, Aivaras

    2016-01-01

    The fabrication of polylactic acid (PLA)-carbonated hydroxyapatite (cHAP) composite material from synthesised phase pure nano-cHAP and melted PLA by mechanical mixing at 220-235{\\deg}C has been developed in this study. Topographical structuring of PLA-cHAP composite surfaces was performed by direct laser writing (DLW). Microstructured surfaces and the apatite distribution within the composite and formed grooves were evaluated by optical and scanning electron microscopies. The influence of the dopant concentration as well as the laser power and translation velocity on the composite surface morphology is discussed. The synthesis of carbonated hydroxyapatite (cHAP) nanocrystalline powders via wet chemistry approach from calcium acetate and diammonium hydrogen phosphate precursors together with crosslinking and complexing agents of polyethylene glycol, poly(vinyl alcohol) and triethanolamine is also reported. Thermal decomposition of the gels and formation of nanocrystalline cHAP were evaluated by thermal analysi...

  3. Characteristics and experimental application of polylactic acid copolymer composite sustained-release drug materials%聚乳酸共聚物复合缓释药物的材料特征与实验应用

    Institute of Scientific and Technical Information of China (English)

    王丹; 姜航航

    2013-01-01

    BACKGROUND: Polylactic acid copolymer composite sustained-release drug materials can reduce the toxic side effects of drugs, extend the action time and improve the effect of the drugs, and it is the hot spot of the drug research recently. OBJECTIVE: To identify the characteristics and experimental application of various polylactic acid copolymer composite sustained-release drug materials. METHODS: Different types of drugs were copolymerized with the polylactic acid to form the polylactic acid copolymer composite sustained-release drug materials, and the drug release characteristics and the treatment effect of various polylactic acid copolymer composite sustained-release drug materials in the animal experimental studies were analyzed. RESULTS AND CONCLUSION: Studies have found that many types of drug can be copolymerized with the polylactic acid and form the polylactic acid copolymer composite sustained-release drug material system, including the anti-tumor drugs, anti-bacterial drugs, anti-viral drugs, anti-tuberculosis drugs, drugs for the prevention and treatment of cardiovascular and cerebrovascular diseases and the metabolic drugs. The drugs above can prolong the action time, effectively stabilize the plasma concentration, obtain the role of targeted therapy and significantly improve the treatment effect after copolymerized with the polylactic acid and form the polylactic acid copolymer composite sustained-release drug material system.%  背景:聚乳酸共聚物复合药物缓释材料能够降低药物的毒副作用,延长药物作用时间,提高药物治疗效果,是目前药物研究的热点之一。目的:明确各种聚乳酸共聚物复合药物缓释材料的特征以及实验应用效果。方法:将不同种类的药物与聚乳酸进行共聚结合形成聚乳酸共聚物复合药物缓释材料,分析多种聚乳酸共聚物复合药物缓释材料的释药特征,并分析动物实验研究中聚乳酸共聚物复合缓释药

  4. Monolithic calcium phosphate/poly(lactic acid) composite versus calcium phosphate-coated poly(lactic acid) for support of osteogenic differentiation of human mesenchymal stromal cells.

    Science.gov (United States)

    Tahmasebi Birgani, Zeinab; van Blitterswijk, Clemens A; Habibovic, Pamela

    2016-03-01

    Calcium phosphates (CaPs), extensively used synthetic bone graft substitutes, are often combined with other materials with the aim to overcome issues related to poor mechanical properties of most CaP ceramics. Thin ceramic coatings on metallic implants and polymer-ceramic composites are examples of such hybrid materials. Both the properties of the CaP used and the method of incorporation into a hybrid structure are determinant for the bioactivity of the final construct. In the present study, a monolithic composite comprising nano-sized CaP and poly(lactic acid) (PLA) and a CaP-coated PLA were comparatively investigated for their ability to support proliferation and osteogenic differentiation of bone marrow-derived human mesenchymal stromal cells (hMSCs). Both, the PLA/CaP composite, produced using physical mixing and extrusion and CaP-coated PLA, resulting from a biomimetic coating process at near-physiological conditions, supported proliferation of hMSCs with highest rates at PLA/CaP composite. Enzymatic alkaline phosphatase activity as well as the mRNA expression of bone morphogenetic protein-2, osteopontin and osteocalcin were higher on the composite and coated polymer as compared to the PLA control, while no significant differences were observed between the two methods of combining CaP and PLA. The results of this study confirmed the importance of CaP in osteogenic differentiation while the exact properties and the method of incorporation into the hybrid material played a less prominent role. PMID:26787486

  5. 聚乳酸纤维针织面料的生产实践%Knitting Practice of Polylactic Acid Fiber Knitted Fabric

    Institute of Scientific and Technical Information of China (English)

    宋艳辉

    2014-01-01

    The paper develops a new kind of environment-friendly knitted fabric by using polylactic acid fiber on the double-bed circular knitting machine. It introduces the environment-friendly PLA fiber and the characteris-tics of this kind of knitted fabric. Furthermore, it presents the knitting technology and dyeing and finishing process. The results show that the fabric bears good moisture absorption and fast-dry properties, and can still keep a new appearance after washing, which is suitable for making sportswear and T-shirt. The application of polylactic acid fiber in this paper can expand the approaches of developing of environment-friendly knitted fabric with good eco-nomic and social benefit.%采用聚乳酸纤维在双面针织大圆机上开发一款新颖绿色环保型针织面料。阐述绿色环保聚乳酸纤维及其所生产面料的性能特点,并以生产实例提出了面料的编织工艺和染整工艺。该面料吸湿快干,且洗后外观如新,是制作运动服与T恤衫的理想面料。运用聚乳酸这个绿色环保型纤维,设计出新颖别致的针织面料,开拓了绿色针织产品的开发途径,创造出良好的经济效益。

  6. Biodegradation of poly(lactic acid) and poly(butylene succinate-co-adipate) by Paenibacillus amylolyticus strain TB-13

    OpenAIRE

    Teeraphatpornchai, Teerawat

    2003-01-01

    Polymer materials developed during the last 80 years are generally resistant to microbial attack, a property that is now currently regarded as a shortcoming concerning solid waste management. As a source of alternative environmental friendly materials, the synthesis of degradable polymers is becoming of considerable interest.Recently, increasing iterest has been devoted to understanding the degradation mechanisms of polymers in the environment. A number of synthetic polymers have been referre...

  7. 聚乳酸薄膜对西兰花的保鲜效果分析%Effect of Polylactic Acid Film Packaging on Preservation of Broccoli

    Institute of Scientific and Technical Information of China (English)

    李伟; 张一珠; 付正义; 张伟阳; 程树军

    2016-01-01

    Polylactic acid (PLA) film was applied to preserve broccoli with polyethylene (PE) film packaging and without packaging as controls. The effect of PLA film on preservation of broccoli quality was investigated by periodically recording quality changes during storage at a constant temperature of (20 ± 3) ℃. The results showed that the vitamin C and chlorophyll contents of broccoli were declined, while the relative conductivity and peroxidase (POD) activity were increased during storage under all three packaging conditions. The broccoli packaged in PLA film showed minimum changes. From the above results it is clear that PLA film can preserve broccoli quality obviously and effectively prolong its shelf life at normal temperature.%用聚乳酸(polylactic acid,PLA)薄膜包装西兰花,以聚乙烯(polyethylene,PE)薄膜包装和无膜包装为对照组,在(20±3)℃条件下对西兰花的相关指标进行定期测定,研究PLA薄膜对西兰花的保鲜效果。结果表明:在PLA薄膜、PE薄膜和无膜包装贮藏过程中,西兰花的VC、叶绿素含量均呈下降趋势,且前者含量明显高于后两者,而相对电导率、过氧化物酶活性均呈上升趋势,前者明显低于后两者。可见,PLA薄膜包装处理对常温条件下的西兰花有明显的保鲜效果,能有效地延长西兰花的常温货架期。

  8. Molecular Design of Synthetic Biodegradable Polymers as Cell Scaffold Materials

    Institute of Scientific and Technical Information of China (English)

    WANG Shen-guo; WAN Yu-qing; CAI Qing; HE Bin; CHEN Wen-na

    2004-01-01

    Poly(lactic acid) and its copolymers are regarded as the most useful biomaterials. The good biocompatibility, biodegradability and mechanical properties of them make the synthetic biodegradable polymers have primary application to tissue engineering. The advantages and disadvantages of the synthetic biodegradable polymers as cell scaffold materials are evaluated. This article reviews the modification of polylactide-family aliphatic polymers to improve the cell affinity when the polymers are used as cell scaffolds. We have developed four main approaches: to modify polyester cell scaffolds in combination of plasma treating and collagen coating; to introduce hydrophilic segments into aliphatic polyester backbones; to introduce pendant functional groups into polyester chains; to modify polyester with dextran. The results of the cell cultures prove that the approaches mentioned above have improved the cell affinity of the polyesters and have modulated cell function such as adhesion, proliferation and migration.

  9. Synthesis and characterization of biodegradable polymer: Poly (ethene maleic acid ester-co-D,L-lactide acid)

    Institute of Scientific and Technical Information of China (English)

    Mei Na Huang; Yan Feng Luo; Jia Chen; Yong Gang Li; Chun Hua Fu; Yuan Liang Wang

    2007-01-01

    A novel biodegradable polymer-poly (ethene maleic acid ester-co-D,L-lactide acid) was synthesized by copolymerizing lactide and prepolymer, which was prepared by the condensation of maleic anhydride and glycol, using p-toluene sulphonic acid as a catalyst, attempting to improve the hydrophilicity, increase flexibility and modulate the degradation rate. FTIR, 1H NMR, MALLS and DSC were employed to characterize these polymers.

  10. Engineered biosynthesis of biodegradable polymers.

    Science.gov (United States)

    Jambunathan, Pooja; Zhang, Kechun

    2016-08-01

    Advances in science and technology have resulted in the rapid development of biobased plastics and the major drivers for this expansion are rising environmental concerns of plastic pollution and the depletion of fossil-fuels. This paper presents a broad view on the recent developments of three promising biobased plastics, polylactic acid (PLA), polyhydroxyalkanoate (PHA) and polybutylene succinate (PBS), well known for their biodegradability. The article discusses the natural and recombinant host organisms used for fermentative production of monomers, alternative carbon feedstocks that have been used to lower production cost, different metabolic engineering strategies used to improve product titers, various fermentation technologies employed to increase productivities and finally, the different downstream processes used for recovery and purification of the monomers and polymers.

  11. Engineered biosynthesis of biodegradable polymers.

    Science.gov (United States)

    Jambunathan, Pooja; Zhang, Kechun

    2016-08-01

    Advances in science and technology have resulted in the rapid development of biobased plastics and the major drivers for this expansion are rising environmental concerns of plastic pollution and the depletion of fossil-fuels. This paper presents a broad view on the recent developments of three promising biobased plastics, polylactic acid (PLA), polyhydroxyalkanoate (PHA) and polybutylene succinate (PBS), well known for their biodegradability. The article discusses the natural and recombinant host organisms used for fermentative production of monomers, alternative carbon feedstocks that have been used to lower production cost, different metabolic engineering strategies used to improve product titers, various fermentation technologies employed to increase productivities and finally, the different downstream processes used for recovery and purification of the monomers and polymers. PMID:27260524

  12. Synthesis of Bio-Based Poly(lactic acid-co-10-hydroxy decanoate Copolymers with High Thermal Stability and Ductility

    Directory of Open Access Journals (Sweden)

    Dongjian Shi

    2015-03-01

    Full Text Available Novel bio-based aliphatic copolyesters, poly(lactic acid-co-10-hydroxy decanoate (P(LA-co-HDA, PLH, were successfully synthesized from lactic acid (LA and 10-hydroxycapric acid (HDA by a thermal polycondensation process, in the presence of p-toluenesulfonic acid (p-TSA and SnCl2·2H2O as co-catalyst. The copolymer structure was characterized by Fourier transform infrared (FTIR and proton nuclear magnetic resonance (1H NMR. The weight average molecular weights (Mw of PLH, from gel permeation chromatography (GPC measurements, were controlled from 18,500 to 37,900 by changing the molar ratios of LA and HDA. Thermogravimetric analysis (TGA results showed that PLH had excellent thermal stability, and the decomposition temperature at the maximum rate was above 280 °C. The glass transition temperature (Tg and melting temperature (Tm of PLH decreased continuously with increasing the HDA composition by differential scanning calorimetry (DSC measurements. PLH showed high ductility, and the breaking elongation increased significantly by the increment of the HDA composition. Moreover, the PLH copolymer could degrade in buffer solution. The cell adhesion results showed that PLH had good biocompatibility with NIH/3T3 cells. The bio-based PLH copolymers have potential applications as thermoplastics, elastomers or impact modifiers in the biomedical, industrial and agricultural fields.

  13. Degradation and osteogenic potential of a novel poly(lactic acid/nano-sized β-tricalcium phosphate scaffold

    Directory of Open Access Journals (Sweden)

    Cao L

    2012-11-01

    % nβ-TCP as a promising scaffold for bone regeneration.Keywords: poly (lactic acid, β-tricalcium phosphate, biodegradation, porous scaffold, bone regeneration

  14. Impact Strength and Flexural Properties Enhancement of Methacrylate Silane Treated Oil Palm Mesocarp Fiber Reinforced Biodegradable Hybrid Composites

    OpenAIRE

    Chern Chiet Eng; Nor Azowa Ibrahim; Norhazlin Zainuddin; Hidayah Ariffin; Wan Md Zin Wan Yunus

    2014-01-01

    Natural fiber as reinforcement filler in polymer composites is an attractive approach due to being fully biodegradable and cheap. However, incompatibility between hydrophilic natural fiber and hydrophobic polymer matrix restricts the application. The current studies focus on the effects of incorporation of silane treated OPMF into polylactic acid (PLA)/polycaprolactone (PCL)/nanoclay/OPMF hybrid composites. The composites were prepared by melt blending technique and characterize the composite...

  15. 以马铃薯残渣为原料的端羟基乳酸预聚物的制备%Synthesis of Hydroxyl Terminated Prepolymer of Polylactic Acid Using Potato Waste as Raw Materials

    Institute of Scientific and Technical Information of China (English)

    张红印; Fu-H sianChang; 陈少峰

    2011-01-01

    [目的]利用马铃薯残渣为原料合成乳酸预聚物,为聚乳酸的生产工艺改造提供理论依据.[方法]将由马铃薯残渣发酵所得的乳酸采用熔融缩聚法合成乳酸预聚物,并对此方法进行了优化.[结果]最佳工艺:催化剂辛酸亚锡的用量1%,熔融缩聚时间10 h,反应温度170℃,1,4-丁二醇用量1%.[结论]熔融缩聚法聚合所得的聚乳酸预聚物的最高分子量为3059 g/mol,用马铃薯残渣为原料合成乳酸预聚物简单易行,该方法提供了一种新的废物利用途径.%[Objective]The synthesis of hydroxyl terminated prepolyraer of polylactic acid using potato waste was studied to provide theoretical basis for reformation of productive technology of polylactic acid. [ Methods ] This study applied direct condensation method for polymerization of lactic acid produced from potato waste and the methods were optimized. [ Result]The results showed the following optimum conditions for polymerization :catalyst dosage:1%,reaction time: 10 h,reaction temperature; 170℃ ,1,4 - Butanediol dosage;1%. [Conclusion]The highest molecular weight of polylactic acid prepolymer obtained by melt condensation polymerization reached 3 059 g/mol. This study provides an alternative substitute for polylactic acid synthesis,which helps transfer low value potato waste to high value product.

  16. Controlled release of drug and better bioavailability using poly(lactic acid-co-glycolic acid) nanoparticles.

    Science.gov (United States)

    Pandey, Sanjeev K; Patel, Dinesh K; Maurya, Akhilendra K; Thakur, Ravi; Mishra, Durga P; Vinayak, Manjula; Haldar, Chandana; Maiti, Pralay

    2016-08-01

    Tamoxifen (Tmx) embedded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PLGA-Tmx) is prepared to evaluate its better DNA cleavage potential, cytotoxicity using Dalton's lymphoma ascite (DLA) cells and MDA-MB231 breast cancer cells. PLGA-Tmx nanoparticles are prepared through emulsified nanoprecipitation technique with varying dimension of 17-30nm by changing the concentrations of polymer, emulsifier and drug. Nanoparticles dimension are measured through electron and atomic force microscopy. Interactions between tamoxifen and PLGA are verified through spectroscopic and calorimetric methods. PLGA-Tmx shows excellent DNA cleavage potential as compared to pure Tmx raising better bioavailability. In vitro cytotoxicity studies indicate that PLGA-Tmx reduces DLA cells viability up to ∼38% against ∼15% in pure Tmx. Hoechst stain is used to detect apoptotic DLA cells through fluorescence imaging of nuclear fragmentation and condensation exhibiting significant increase of apoptosis (70%) in PLGA-Tmx vis-à-vis pure drug (58%). Enhanced DNA cleavage potential, nuclear fragmentation and condensation in apoptotic cells confirm greater bioavailability of PLGA-Tmx as compared to pure Tmx in terms of receptor mediated endocytosis. Hence, the sustained release kinetics of PLGA-Tmx nanoparticles shows much better anticancer efficacy through enhanced DNA cleavage potential and nuclear fragmentation and, thereby, reveal a novel vehicle for the treatment of cancer. PMID:27112980

  17. Synthesis and characterization of new biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the sodium salt of lactic acid ester and sodium methoxyethoxyethoxide.Their structures were confirmed by ~(31)p NMR,~1H NMR,~(13)C NMR,IR,DSC,and elemental analysis.The lower critical solution temperature(LCST) behavior in water and in vitro degradation property of the polymers was investigated....

  18. Biodegradability of poly(lactic-co-glycolic acid) after femtosecond laser irradiation.

    Science.gov (United States)

    Shibata, Akimichi; Yada, Shuhei; Terakawa, Mitsuhiro

    2016-01-01

    Biodegradation is a key property for biodegradable polymer-based tissue scaffolds because it can provide suitable space for cell growth as well as tailored sustainability depending on their role. Ultrashort pulsed lasers have been widely used for the precise processing of optically transparent materials, including biodegradable polymers. Here, we demonstrated the change in the biodegradation of a poly(lactic-co-glycolic acid) (PLGA) following irradiation with femtosecond laser pulses at different wavelengths. Microscopic observation as well as water absorption and mass change measurement revealed that the biodegradation of the PLGA varied significantly depending on the laser wavelength. There was a significant acceleration of the degradation rate upon 400 nm-laser irradiation, whereas 800 nm-laser irradiation did not induce a comparable degree of change. The X-ray photoelectron spectroscopy analysis indicated that laser pulses at the shorter wavelength dissociated the chemical bonds effectively, resulting in a higher degradation rate at an early stage of degradation. PMID:27301578

  19. Enhanced Biodegradability, Lubricity and Corrosiveness of Lubricating Oil by Oleic Acid Diethanolamide Phosphate

    Directory of Open Access Journals (Sweden)

    Fang Jianhua

    2012-09-01

    Full Text Available Impacts of oleic acid diethanolamide phosphate (abbreviated as ODAP as an additive on biodegradability, anti-wear capacity, friction-reducing ability and corrosiveness of an unreadily biodegradable HVI 350 mineral lubricating oil was studied. The biodegradabilities of neat lubricating oil and its formulations with ODAP were evaluated on a biodegradation tester. Furthermore, the anti-wear and friction-reducing abilities and the corrosiveness of neat oil and the formulated oils were determined on a four-ball tribotester and a copper strip corrosion tester, respectively. The results indicated that ODAP markedly enhanced biodegradability as well as anti-wear and friction-reducing abilities of the lubricating oil. On the other hand, excellent color ratings of copper strips for both neat oil and the ODAP-doped oil were obtained in the corrosion tests, demonstrating that the corrosiveness of neat oil and the doped oil was negligible, although the latter seemed to provide slightly better anti-corrosion ability.

  20. Kinetics of phenolic and phthalic acid esters biodegradation in membrane bioreactor (MBR) treating municipal landfill leachate.

    Science.gov (United States)

    Boonnorat, Jarungwit; Chiemchaisri, Chart; Chiemchaisri, Wilai; Yamamoto, Kazuo

    2016-05-01

    The kinetic of phenolic and phthalic acid esters (PAEs) biodegradation in membrane bioreactor (MBR) treating municipal landfill leachate was investigated. Laboratory-scale MBR was fed with mixture of fresh and stabilized landfill leachate containing carbon to nitrogen (C/N) ratio of 10, 6, 3 and operated under different solid retention time (SRT) of 90, 15 and 5 d. Batch experiments using MBR sludge obtained from each steady-state operating condition revealed highest biodegradation rate constant (k) of 0.059-0.092 h(-1) of the phenolic and PAEs compounds at C/N of 6. Heterotrophic bacteria were the major group responsible for biodegradation of compounds whereas the presence of ammonia-oxidizing bacteria (AOB) helped accelerating their removals. Heterotrophic nitrifying bacteria found under high ammonia condition had an important role in enhancing the biodegradation of phenols and PAEs by releasing phenol hydroxylase (PH), esterase (EST) and phthalate dioxygenase (PDO) enzymes and the presence of AOB helped improving biodegradation of phenolic and PAEs compounds through their co-metabolism. PMID:26908045

  1. Radiation-induced grafting of acrylic acid onto polypropylene film and its biodegradability

    Science.gov (United States)

    Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Chaudhari, C. V.; Dubey, K. A.; Varshney, L.

    2016-06-01

    Polypropylene based commodity polyolefins are widely used in packaging, manufacturing, electrical, pharmaceutical and other applications. The aim of the present work is to study the effect of grafting of acrylic acid on the biodegradability of acrylic acid grafted polypropylene. The effect of different conditions showed that grafting percentage increased with increase in monomer concentration, radiation dose and inhibitor concentration but decreased with increase in radiation dose rate. The maximum grafting of 159.4% could be achieved at optimum conditions. The structure of grafted polypropylene films at different degree of grafting was characterized by EDS, FTIR, TGA, DSC, SEM and XRD. EDS studies showed that the increase in acrylic acid grafting percentage increased the hydrophilicity of the grafted films. FTIR studies indicated the presence of acrylic acid on the surface of polypropylene film. TGA studies revealed that thermal stability decreased with increase in grafting percentage. DSC studies showed that melting temperature and crystallinity of the grafted polypropylene films lower than polypropylene film. SEM studies indicated that increase in acrylic acid grafting percentage increased the wrinkles in the grafted films. The maximum biodegradability could be achieved to 6.85% for 90.5% grafting. This suggested that microorganisms present in the compost could biodegrade acrylic acid grafted polypropylene.

  2. Aerobic biodegradation of azo dye Acid Black-24 by Bacillus halodurans.

    Science.gov (United States)

    Prasad, A S Arun; Rao, K V Bhaskara

    2014-05-01

    Bacillus halodurans MTCC 865 was employed for decolorization of textile azo dye, Acid Black-24 (AB-24). Thousand mgl⁻¹ of AB-24 was decolorized with 90% efficiency by the strain within 6 hrs at pH 9 and 37 °C with 5% NaCl under static conditions in screening medium. Decolorization was evaluated by measuring the periodic decrease in absorbance at 557 nm (λ(max)). Biodegradation of Acid Black-24 was determined by FTIR and HPLC. The FTIR spectrum of the AB-24 dye suggests the presence of azo bond (-N = N-) peak at 1618.28 cm⁻¹. Absence of the azo bond in the degraded sample spectrum indicates biodegradation of the dye. Formation of metabolites with different retention times in HPLC analysis further confirmed degradation of the azo dye, Acid Black-24 by Bacillus halodurans.

  3. Enteric-coated capsule containing β-galactosidase-loaded polylactic acid nanocapsules: enzyme stability and milk lactose hydrolysis under simulated gastrointestinal conditions.

    Science.gov (United States)

    He, Hongjun; Zhang, Xueting; Sheng, Yan

    2014-11-01

    In order to protect peroral β-galactosidase from being degraded and hydrolyse milk lactose efficiently in the environments of gastrointestinal tract, a double-capsule delivery system composed of enteric-coated capsule and polylactic acid (PLA) nanocapsules (NCs) was developed for encapsulation of β-galactosidase. β-galactosidase-loaded PLA NCs in the size range of 100-200 nm were prepared by a modified w1/o/w2 technique. During the encapsulation process, dichloromethane/ethyl acetate (1 : 1, v/v) as the solvent composition, high-pressure homogenisation (150 bar, 3 min) as the second emulsification method and polyvinyl alcohol or Poloxamer 188 as a stabiliser in the inner phase could efficiently improve the activity retention of β-galactosidase (>90%). Subsequently, the prepared NCs were freeze-dried and filled in a hydroxypropyl methylcellulose phthalate (HP55)-coated capsule. In vitro results revealed that the HP55-coated capsule remained intact in the simulated gastric fluid and efficiently protected the nested β-galactosidase from acidic denaturation. Under the simulated intestinal condition, the enteric coating dissolved rapidly and released the β-galactosidase-loaded PLA NCs, which exhibited greater stability against enzymatic degradation and higher hydrolysis ratio (∼100%) towards milk lactose than the free β-galactosidase. These results suggest that this double-capsule delivery system represents promising candidate for efficient lactose hydrolysis in the gastrointestinal tract.

  4. Preparation of biodegradable PLA/PLGA membranes with PGA mesh and their application for periodontal guided tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Jin; Kang, Inn-Kyu [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Yoon, Suk Joon [Department of Biology, Sookmyung Women' s University, Hyochangwongil 52, Yongsan-gu, Seoul 140-742 (Korea, Republic of); Yeo, Guw-Dong; Pai, Chaul-Min, E-mail: ikkang@knu.ac.k [Samyang Central R and D Center, 63-2 Hwaam-dong, Yusung-gu, Daejeon 305-717 (Korea, Republic of)

    2009-10-15

    A biodegradable polylactic acid (PLA)/poly(glycolide-co-lactide) copolymer (PLGA) membrane with polyglycolic acid (PGA) mesh was prepared to aid the effective regeneration of defective periodontal tissues. The microporous membrane used in this study consists of biodegradable polymers, and seems to have a structure to provide appropriate properties for periodontal tissue regeneration. Based on the albumin permeation test, it is known that the biodegradable membrane exhibits the suitable permeability of nutrients. The membrane maintained its physical integrity for 6-8 weeks, which could be sufficient to retain space in the periodontal pocket. Cell attachment and cytotoxicity tests were performed with respect to the evaluation of biocompatibility of the membrane. As a result, the membrane did not show any cytotoxicity. The safety and therapeutic efficacies of the biodegradable membranes were confirmed in animal tests.

  5. Preparation and toxicity test of chitosan-polylactic acid film%壳聚糖聚乳酸膜的制备和毒性试验研究

    Institute of Scientific and Technical Information of China (English)

    陈康; 李瑛; 谢良宪

    2011-01-01

    Objective To manufacture a biomembrane for the primary repair of colonic fistula, and to evaluate its acute general toxicity and cytotoxicity. Methods After the preparation of polylactic acid film( PAF )and chitosan - polylactic acid film ( CPAF ), acute general toxicity and cytotoxicity examinations were performed with trypanblau cytoactive count and MTT reduction assay according to pharmacopeia for CPAF. Results A method for the preparation of CPAF was successfully established. There were no significant differences in physical performances between PAF and CPAF. No death and paradoxical reaction in mice were found by acute general toxicity test. Trypanblau cytoactive count and MTT reduction assay showed no significant differences between the two biofilms.Conclusion CPAF meets physic requirement of pharmacopeia with no acute general toxicity and cytotoxicity. Its biocompatibility is good according to preliminary assessment.%目的 研制结肠瘘的一期修复生物膜,并进行相关急性毒性和细胞毒性试验.方法 制备聚乳酸膜和壳聚糖聚乳酸膜,按照药典要求进行壳聚糖聚乳酸膜的小鼠急性全身毒性试验和细胞毒性试验(台盼蓝计数细胞活性和MTT法检测细胞活性).结果 建立了壳聚糖聚乳酸膜的制备方法,聚乳酸膜与壳聚糖聚乳酸膜的物理性能比较无统计学差异;小鼠急性全身毒性试验无动物死亡和异常反应;细胞毒性试验显示,两膜比较无统计学差异.结论 壳聚糖聚乳酸膜的物理指标达到药典要求,无急性全身毒性反应和细胞毒性反应,初步评价生物相容性好.

  6. 三嗪膨胀阻燃聚乳酸的制备及其性能%Preparation and Properties of Polylactic Acid with Triazine Intumescent Flame Retardant

    Institute of Scientific and Technical Information of China (English)

    李旭; 许苗军; 李斌

    2016-01-01

    将实验室自制的三嗪大分子成炭发泡剂(CFA)、聚磷酸铵(APP)及硅树脂复配成膨胀阻燃剂(IFR)添加到聚乳酸(PLA)材料中制备阻燃PLA(IFR-PLA)材料,通过极限氧指数(LOI)和垂直燃烧(UL-94)测试研究了材料的阻燃性能.通过热重分析(TGA)测试研究了材料的热降解行为和成炭性能,通过锥形量热(CONE)测试研究了材料的燃烧行为,并对其燃烧后残炭的形貌进行研究.结果表明:当APP与CFA的质量比为5∶1,IFR的添加量为15%时,IFR-PLA材料通过UL-94 V-0级,LOI值达33.5%.IFR的加入促进了PLA材料的降解和成炭,从而提高了材料的阻燃性能.%The triazine char foaming agent (CFA) made by lab was mixed with APP and silicone to prepare intumescent flame retardant (IFR),afterwards IFR was incorporated into polylactic acid (PLA) to prepare flame retardant materials.The flame retardant properties of prepared materials were investigated by limiting oxygen index (LOI) and vertical burning (UL94) tests,the thermal decomposition behavior and charring performance of materials was studied by thermogravity analysis (TGA).The burning behavior of the materials was tested by cone calorimeter (CONE),and studying the morphology of carbon residue combustion of materials.The results demonstrated that the flame retarded polylactic acid materials could pass UL-94 V-0 rating and its LOI value reach 33.5% when the loading amount of IFR was 15%,the mass ratio of APP/CFA was 5∶ 1.During the combustion process,IFR could promote the degradation and charring of the PLA material,thereby improving the flame retardant properties of the material.

  7. Self-aggregated nanoparticles based on amphiphilic poly(lactic acid-grafted-chitosan copolymer for ocular delivery of amphotericin B

    Directory of Open Access Journals (Sweden)

    Zhou WJ

    2013-09-01

    Full Text Available Wenjun Zhou,1 Yuanyuan Wang,2 Jiuying Jian,2 Shengfang Song1 1Department of Ophthalmology, Yongchuan Hospital, Chongqing Medical University, Chongqing, People’s Republic of China; 2College of Life Science, Chongqing Medical University, Chongqing, People’s Republic of China Background: The purpose of this study was to develop a self-aggregated nanoparticulate vehicle using an amphiphilic poly(lactic acid-grafted-chitosan (PLA-g-CS copolymer and to evaluate its potential for ocular delivery of amphotericin B. Methods: A PLA-g-CS copolymer was synthesized via a “protection-graft-deprotection” procedure and its structure was confirmed by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and X-ray diffraction spectra. Amphotericin B-loaded nanoparticles based on PLA-g-CS (AmB/PLA-g-CS were prepared by the dialysis method and characterized for particle size, zeta potential, and encapsulation efficiency. Studies of these AmB/PLA-g-CS nanoparticles, including their mucoadhesive strength, drug release properties, antifungal activity, ocular irritation, ocular pharmacokinetics, and corneal penetration were performed in vitro and in vivo. Results: Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and X-ray diffraction spectra showed that the PLA chains were successfully grafted onto chitosan molecules and that crystallization of chitosan was suppressed. The self-aggregated PLA-g-CS nanoparticles had a core-shell structure with an average particle size of approximately 200 nm and zeta potentials higher than 30 mV. Amphotericin B was incorporated into the hydrophobic core of the nanoparticles with high encapsulation efficiency. Sustained drug release from the nanoparticles was observed in vitro. The ocular irritation study showed no sign of irritation after instillation of the PLA-g-CS nanoparticles into rabbit eyes. The minimal inhibitory concentration of the AmB/PLA-g-CS nanoparticles showed antifungal

  8. 毒死蜱—聚乳酸微球的制备及其性能评价%Preparation and characteristics analysis of microspheres of chlorpyrifos and polylactic acid

    Institute of Scientific and Technical Information of China (English)

    郭瑞峰; 黄彬彬; 杨晓伟; 吴祖建; 吴刚

    2011-01-01

    The sustained-release microspheres of chlorpyrifos was prepared by solvent evaporation method using biodegradable polylactic acid (PLA) as wall materials and chlorpyrifos as core materials. The effects of ratio between core materials to wall materials ( chlorpyrifos weight/ PLA weight, CP value) and the concentration of PLA on the characteristics of microsphere were investigated. The results indicated that particle diameter, drug-loading rate and entrapment efficiency of microsphere increased with the increase of the concentration of PLA. The particle diameter and drug-loading rate of microsphere decreased when the CP value was decreased from 1:2 to 1:5. When the CP value were 1:3 and 1: 4, the entrapment efficiency of microsphere were 89. 88% ± 1. 67% and 90. 55% ± 1. 86% , respectively. The smooth and intact microspheres of chlorpyrifos were formed when the CP value were lower than 1:2. The differential scanning calorimetry ( DSC) determination demonstrated that chlorpyrifos and PLA were combined well to form the microspheres. The results indicated that the appropriate concentration of PLA and CP value contributes to the property of the chlorpyrifos microspheres.%以毒死蜱为芯材,以生物可降解材料聚乳酸(PLA)为载体(壁材),采用溶剂挥发法制备了毒死蜱缓释微球,考察了芯壁材质量比及聚乳酸浓度对微球质量的影响.结果表明:当聚乳酸浓度增加时,载药量和包封率、粒径均随之增加;当芯壁材质量比减小(由1:2减小至1:5)时,微球粒径、载药量也逐渐减小;包封率在芯壁材质量比为1:3和1:4时分别为89.88%±1.67%和90.55%±1.86%;当芯壁材质量比小于1∶2时,微球呈光滑完整的球形.差示扫描量热检测分析证明,毒死蜱和聚乳酸能够有机地结合为一体.表明合适的芯壁材比例和聚乳酸浓度有利于提高制备微球的质量.

  9. Biodegradation of 5-Nitroanthranilic Acid by Bradyrhizobium sp. Strain JS329▿

    OpenAIRE

    Qu, Yi; Spain, Jim C.

    2010-01-01

    Biodegradation of synthetic compounds has been studied extensively, but the metabolic diversity required for catabolism of many natural compounds has not been addressed. 5-Nitroanthranilic acid (5NAA), produced in soil by Streptomyces scabies, is also the starting material for synthetic dyes and other nitroaromatic compounds. Bradyrhizobium JS329 was isolated from soil by selective enrichment with 5NAA. When grown on 5NAA, the isolate released stoichiometric amounts of nitrite and half of the...

  10. Nanocomposites of Polyacrylic Acid Nanogels and Biodegradable Polyhydroxybutyrate for Bone Regeneration and Drug Delivery

    Directory of Open Access Journals (Sweden)

    Mikael Larsson

    2014-01-01

    Full Text Available Biodegradable cell scaffolds and local drug delivery to stimulate cell response are currently receiving much scientific attention. Here we present a nanocomposite that combines biodegradation with controlled release of lithium, which is known to enhance bone growth. Nanogels of lithium neutralized polyacrylic acid were synthesized by microemulsion-templated polymerization and were incorporated into a biodegradable polyhydroxybutyrate (PHB matrix. Nanogel size was characterized using dynamic light scattering, and the nanocomposites were characterized with regard to structure using scanning electron microscopy, mechanical properties using tensile testing, permeability using tritiated water, and lithium release in PBS using a lithium specific electrode. The nanogels were well dispersed in the composites and the mechanical properties were good, with a decrease in elastic modulus being compensated by increased tolerance to strain in the wet state. Approximately half of the lithium was released over about three hours, with the remaining fraction being trapped in the PHB for subsequent slow release during biodegradation. The prepared nanocomposites seem promising for use as dual functional scaffolds for bone regeneration. Here lithium ions were chosen as model drug, but the nanogels could potentially act as carriers for larger and more complex drugs, possibly while still carrying lithium.

  11. Biodegradability of four phthalic acid esters under anaerobic condition assessed using natural sediment

    Institute of Scientific and Technical Information of China (English)

    Ruttapol Lertsirisopon; Satoshi Soda; Kazunari Sei; Michihiko Ike; Masanori Fujita

    2006-01-01

    Biodegradability of di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), di-ethylhexyl phthalate (DEHP), and di-isononyl phthalate (DINP) under an anaerobic condition was evaluated using three natural sediment microcosms obtained from ponds in Osaka, which had not been significantly polluted by the chemicals. The degradabilities of the four phthalic acid esters(PAEs)were analyzed by a first-order kinetic model with a lag phase and ranked as DBP>BBP>>DEHP>DINP. The PAEs with shorter alkyl-chains, DBP and BBP, were degraded with quite short lag phases near to zero and short half-lives of a few days. The PAEs with longer alkyl-chains, DEHP and DINP, were degraded with lag phases of 5-30 d and the quite long half-lives of a couple of hundred days. Although no data was available on the anaerobic biodegradability of DINP before this study, it was clarified that DINP can be degraded with slow degradation rates. The fact that all the three intact sediments were capable of biodegradation of the PAEs suggests that potential of anaerobic biodegradation of PAEs is widespread in the aquatic environment.

  12. Accelerating calcium phosphate growth on NaOH-treated poly-(lactic- co-glycolic acid) by evaporation-induced surface crystallization

    Science.gov (United States)

    Duan, Ke; Tang, Allen; Wang, Rizhi

    2008-12-01

    Poly(lactic- co-glycolic acid) (PLGA) is a promising material for the regeneration of bone tissue, but its surface properties are not optimal for the application. Coating the surface of PLGA with a continuous layer of calcium phosphate is an effective approach to address the limitation. Current coating techniques for PLGA require immersion in supersaturated calcium phosphate solutions for days to weeks. In this study, we report a simple technique to accelerate the coating process to only 2 h immersion in supersaturated solutions. PLGA pellets were first treated with NaOH to increase their hydrophilicity. The NaOH-treated PLGA pellets were repeatedly dipped in a supersaturated calcium phosphate solution and dried in air. After 10 times of the dip-and-dry treatment, a layer of calcium phosphate crystallites uniformly covered the surfaces of the pellets. After the crystallite-covered pellets were immersed in the supersaturated solution for 2 h, about 5-μm thick continuous calcium phosphate coatings formed on the surfaces. The dip-and-dry technique was also applied on a variety of metals and porous structures. An evaporation-induced surface crystallization process was suggested as the mechanism for the dip-and-dry treatment.

  13. Macrophage interactions with polylactic acid and chitosan scaffolds lead to improved recruitment of human mesenchymal stem/stromal cells: a comprehensive study with different immune cells.

    Science.gov (United States)

    Caires, Hugo R; Esteves, Tiago; Quelhas, Pedro; Barbosa, Mário A; Navarro, Melba; Almeida, Catarina R

    2016-09-01

    Despite the importance of immune cell-biomaterial interactions for the regenerative outcome, few studies have investigated how distinct three-dimensional biomaterials modulate the immune cell-mediated mesenchymal stem/stromal cells (MSC) recruitment and function. Thus, this work compares the response of varied primary human immune cell populations triggered by different model scaffolds and describes its functional consequence on recruitment and motility of bone marrow MSC. It was found that polylactic acid (PLA) and chitosan scaffolds lead to an increase in the metabolic activity of macrophages but not of peripheral blood mononuclear cells (PBMC), natural killer (NK) cells or monocytes. PBMC and NK cells increase their cell number in PLA scaffolds and express a secretion profile that does not promote MSC recruitment. Importantly, chitosan increases IL-8, MIP-1, MCP-1 and RANTES secretion by macrophages while PLA stimulates IL-6, IL-8 and MCP-1 production, all chemokines that can lead to MSC recruitment. This secretion profile of macrophages in contact with biomaterials correlates with the highest MSC invasion. Furthermore, macrophages enhance stem cell motility within chitosan scaffolds by 44% but not in PLA scaffolds. Thus, macrophages are the cells that in contact with engineered biomaterials become activated to secrete bioactive molecules that stimulate MSC recruitment. PMID:27628173

  14. Property tuning of poly(lactic acid)/cellulose bio-composites through blending with modified ethylene-vinyl acetate copolymer.

    Science.gov (United States)

    Pracella, Mariano; Haque, Md Minhaz-Ul; Paci, Massimo; Alvarez, Vera

    2016-02-10

    The effect of addition of an ethylene-vinyl acetate copolymer modified with glycidyl methacrylate (EVA-GMA) on the structure and properties of poly(lactic acid) (PLA) composites with cellulose micro fibres (CF) was investigated. Binary (PLA/CF) and ternary (PLA/EVA-GMA/CF) composites obtained by melt mixing in Brabender mixer were analysed by SEM, POM, WAXS, DSC, TGA and tensile tests. The miscibility and morphology of PLA/EVA-GMA blends were first examined as a function of composition: a large rise of PLA spherulite growth rate in the blends was discovered with increasing the EVA-GMA content (0-30 wt%) in the isothermal crystallization both from the melt and the solid state. PLA/EVA-GMA/CF ternary composites displayed improved adhesion and dispersion of fibres into the matrix as compared to PLA/CF system. Marked changes of thermodynamic and tensile parameters, as elastic modulus, strength and elongation at break were observed for the composites, depending on blend composition, polymer miscibility and fibre-matrix chemical interactions at the interface.

  15. Controlled Release of Linalool Using Nanofibrous Membranes of Poly(lactic acid) Obtained by Electrospinning and Solution Blow Spinning: A Comparative Study.

    Science.gov (United States)

    Souza, Michelle A; Oliveira, Juliano E; Medeiros, Eliton S; Glenn, Gregory M; Mattoso, Luiz H C

    2015-08-01

    The controlled-release of natural plant oils such as linalool is of interest in therapeutics, cosmetics, and antimicrobial and larvicidal products. The present study reports the release characteristics of linalool encapsulated at three concentrations (10, 15 and 20 wt.%) in poly(lactic acid) nanofibrous membranes produced by electrospinning and solution blow spinning (SBS) as well as the effect of linalool on fiber morphology and structural properties. PLA nanofibrous membranes were characterized by Scanning Electron Microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and contact angle measurements. The average diameters of the electrospun and solution blow spun nanofibers were similar, ranging from 176 to 240 nm. Linalool behaved as a plasticizer to PLA decreasing the glass transition temperature (Tg), melting point (Tm) and crystallization temperature (TC) of PLA. Curves of the release of linalool at 35 °C were non-linear, showing a clear biphasic pattern consistent with one or more Fickian release components. The time required to release 50% of linalool (t1/2) decreased with increasing linalool concentration. The range in t1/2 values for SBS nanofibers was higher (291-1645s) than the t1/2 values for electrospun fibers (76-575s).

  16. Property tuning of poly(lactic acid)/cellulose bio-composites through blending with modified ethylene-vinyl acetate copolymer.

    Science.gov (United States)

    Pracella, Mariano; Haque, Md Minhaz-Ul; Paci, Massimo; Alvarez, Vera

    2016-02-10

    The effect of addition of an ethylene-vinyl acetate copolymer modified with glycidyl methacrylate (EVA-GMA) on the structure and properties of poly(lactic acid) (PLA) composites with cellulose micro fibres (CF) was investigated. Binary (PLA/CF) and ternary (PLA/EVA-GMA/CF) composites obtained by melt mixing in Brabender mixer were analysed by SEM, POM, WAXS, DSC, TGA and tensile tests. The miscibility and morphology of PLA/EVA-GMA blends were first examined as a function of composition: a large rise of PLA spherulite growth rate in the blends was discovered with increasing the EVA-GMA content (0-30 wt%) in the isothermal crystallization both from the melt and the solid state. PLA/EVA-GMA/CF ternary composites displayed improved adhesion and dispersion of fibres into the matrix as compared to PLA/CF system. Marked changes of thermodynamic and tensile parameters, as elastic modulus, strength and elongation at break were observed for the composites, depending on blend composition, polymer miscibility and fibre-matrix chemical interactions at the interface. PMID:26686158

  17. Enhancement of Mechanical and Dynamic Mechanical Properties of Hydrophilic Nanoclay Reinforced Polylactic Acid/Polycaprolactone/Oil Palm Mesocarp Fiber Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Chern Chiet Eng

    2014-01-01

    Full Text Available In previous studies, the effect of the addition of 1 wt% hydrophilic nanoclay on polylactic acid (PLA/polycaprolactone (PCL/oil palm mesocarp fiber (OPMF biocomposites was investigated by tensile properties, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM. The current studies focus on the effect of addition of 1 wt% hydrophilic nanoclay on mechanical (flexural and impact properties and dynamic mechanical properties of composites. The composites were characterized by the Fourier transform infrared spectroscopy (FTIR and dynamic mechanical analysis (DMA. FTIR spectra show that peak shifting occurs when 1 wt% hydrophilic nanoclay was added to composites. The addition of 1 wt% hydrophilic nanoclay successfully improves the flexural properties and impact resistance of the biocomposites. The storage modulus of biocomposites was decreased when nanoclay was added which indicates that the stiffness of biocomposites was reduced. The loss modulus curve shows that the addition of nanoclay shift two tg in composites become closer to each other which indicates that the incorporation of nanoclay slightly compatibilizes the biocomposites. Tan δ indicated that hybrid composites dissipate less energy compared to biocomposites indicate that addition of clay to biocomposites improves fiber/matrix adhesion. Water sorption test shows that the addition of nanoclay enhances water resistance of composites.

  18. Preparation of hydrophilic poly(lactic acid) tissue engineering scaffold via (PLA)-(PLA-b-PEG)-(PEG) solution casting and thermal-induced surface structural transformation.

    Science.gov (United States)

    Zhu, Xiaomin; Zhong, Tian; Huang, Ran; Wan, Ajun

    2015-01-01

    Porous poly(lactic acid) (PLA) tissue engineering scaffolds with a hydrophilic surface assembled by polyethylene glycol aggregations were prepared by the solvent casting/particulate leaching method from (PLA)-(PLA-b-PEG)-(PEG) blend solution, where the PLA-b-PEG block polymer serves as an amphiphilic glue between two phases. A thermal recrystallization process was inserted before leaching to induce a phase separation, which subsequently squeezes out PEG to form a hydrophilic shell. Characterizations of XRD and DSC indicated the composition and mixing states of materials. The water contact angle test qualitatively presented the excellent hydrophilicity compared to the pure PLA or PLA-PEG simple blend scaffold. The scanning electron microscope results confirmed the formation of porous structure of [Formula: see text] pore size, with an observable phase separation on the surface. The scaffold was degraded in PBS at [Formula: see text], and the degradation exhibits a three-stage behavior, which evidenced the amphiphilically glued phase separations. PMID:26324121

  19. Safety evaluation of a bioglass-polylactic acid composite scaffold seeded with progenitor cells in a rat skull critical-size bone defect.

    Directory of Open Access Journals (Sweden)

    Karam Eldesoqi

    Full Text Available Treating large bone defects represents a major challenge in traumatic and orthopedic surgery. Bone tissue engineering provides a promising therapeutic option to improve the local bone healing response. In the present study tissue biocompatibility, systemic toxicity and tumorigenicity of a newly developed composite material consisting of polylactic acid (PLA and 20% or 40% bioglass (BG20 and BG40, respectively, were analyzed. These materials were seeded with mesenchymal stem cells (MSC and endothelial progenitor cells (EPC and tested in a rat calvarial critical size defect model for 3 months and compared to a scaffold consisting only of PLA. Serum was analyzed for organ damage markers such as GOT and creatinine. Leukocyte count, temperature and free radical indicators were measured to determine the degree of systemic inflammation. Possible tumor occurrence was assessed macroscopically and histologically in slides of liver, kidney and spleen. Furthermore, the concentrations of serum malondialdehyde (MDA and sodium oxide dismutase (SOD were assessed as indicators of tumor progression. Qualitative tissue response towards the implants and new bone mass formation was histologically investigated. BG20 and BG40, with or without progenitor cells, did not cause organ damage, long-term systemic inflammatory reactions or tumor formation. BG20 and BG40 supported bone formation, which was further enhanced in the presence of EPCs and MSCs. This investigation reflects good biocompatibility of the biomaterials BG20 and BG40 and provides evidence that additionally seeding EPCs and MSCs onto the scaffold does not induce tumor formation.

  20. In vitro antimicrobial activity of solution blow spun poly(lactic acid)/polyvinylpyrrolidone nanofibers loaded with Copaiba (Copaifera sp.) oil

    Energy Technology Data Exchange (ETDEWEB)

    Bonan, Roberta F. [Departamento de Engenharia de Materiais (DEMAT), Universidade Federal da Paraíba (UFPB), Cidade Universitária, 58.051-900 João Pessoa, PB (Brazil); Centro de Ciências da Saúde (CCS), Universidade Federal da Paraíba (UFPB), Cidade Universitária, 58.051-900 João Pessoa, PB (Brazil); Bonan, Paulo R.F.; Batista, André U.D.; Sampaio, Fábio C.; Albuquerque, Allan J.R. [Centro de Ciências da Saúde (CCS), Universidade Federal da Paraíba (UFPB), Cidade Universitária, 58.051-900 João Pessoa, PB (Brazil); Moraes, Maria C.B. [Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Ecológica, W/5 Norte (Final) Cenargen (Laboratório de Semioquímicos) ASA NORTE, 70770900 Brasília, DF (Brazil); Mattoso, Luiz H.C. [Laboratório Nacional de Nanotecnologia para o Agronegócio (LNNA), Embrapa Instrumentação Agropecuária (CNPDIA), Rua XV de Novembro, 1452, Centro, 13.560, 970 São Carlos, SP (Brazil); Glenn, Gregory M. [United States Department of Agriculture (USDA), Western Regional Research Center (WRRC), Bioproduct Chemistry and Engineering - BCE, Albany, CA 94710 (United States); and others

    2015-03-01

    In this study poly(lactic acid) (PLA) and polyvinylpyrrolidone (PVP) micro- and nanofiber mats loaded with Copaiba (Copaifera sp.) oil were produced by solution blow spinning (SBS). The Copaiba (Copaifera sp.) oil was characterized by gas chromatography (GC). Neat PLA and four PLA/PVP blends containing 20% (wt.%) oil were spun and characterized by scanning electron microscopy (SEM) and by studying the surface contact angle, in vitro release rate, and antimicrobial activity. All compositions evaluated were able to produce continuous and smooth fibers by SBS. The addition of PVP increased fiber diameter, and decreased the surface contact angle. GC analysis demonstrated that the main component of the Copaiba oil was β-caryophyllene, a known antimicrobial agent. In vitro release tests of Copaiba oil volatiles demonstrated a higher release rate in fibers containing PVP. Fiber mats made from blends containing higher amounts of PVP had greater antimicrobial action against Staphylococcus aureus. The results confirm the potential of the fiber mats for use in controlled drug release and could lead to promising applications in the biomedical field. - Highlights: • An efficient method for production of antimicrobial nanofiber mats using solution blow spinning was reported. • Nanofiber mats containing Copaiba oil were efficient against Staphylococcus aureus. • Nanofiber composition changed morphological properties and antimicrobial action.

  1. Macrophage interactions with polylactic acid and chitosan scaffolds lead to improved recruitment of human mesenchymal stem/stromal cells: a comprehensive study with different immune cells.

    Science.gov (United States)

    Caires, Hugo R; Esteves, Tiago; Quelhas, Pedro; Barbosa, Mário A; Navarro, Melba; Almeida, Catarina R

    2016-09-01

    Despite the importance of immune cell-biomaterial interactions for the regenerative outcome, few studies have investigated how distinct three-dimensional biomaterials modulate the immune cell-mediated mesenchymal stem/stromal cells (MSC) recruitment and function. Thus, this work compares the response of varied primary human immune cell populations triggered by different model scaffolds and describes its functional consequence on recruitment and motility of bone marrow MSC. It was found that polylactic acid (PLA) and chitosan scaffolds lead to an increase in the metabolic activity of macrophages but not of peripheral blood mononuclear cells (PBMC), natural killer (NK) cells or monocytes. PBMC and NK cells increase their cell number in PLA scaffolds and express a secretion profile that does not promote MSC recruitment. Importantly, chitosan increases IL-8, MIP-1, MCP-1 and RANTES secretion by macrophages while PLA stimulates IL-6, IL-8 and MCP-1 production, all chemokines that can lead to MSC recruitment. This secretion profile of macrophages in contact with biomaterials correlates with the highest MSC invasion. Furthermore, macrophages enhance stem cell motility within chitosan scaffolds by 44% but not in PLA scaffolds. Thus, macrophages are the cells that in contact with engineered biomaterials become activated to secrete bioactive molecules that stimulate MSC recruitment.

  2. Near-infrared (NIR) imaging analysis of polylactic acid (PLA) nanocomposite by multiple-perturbation two-dimensional (2D) correlation spectroscopy

    Science.gov (United States)

    Shinzawa, Hideyuki; Murakami, Takurou N.; Nishida, Masakazu; Kanematsu, Wataru; Noda, Isao

    2014-07-01

    Multiple-perturbation two-dimensional (2D) correlation spectroscopy was applied to sets of near-infrared (NIR) imaging data of polylactic acid (PLA) nanocomposite samples undergoing UV degradation. Incorporation of clay nanoparticles substantially lowers the surface free energy barrier for the nucleation of PLA and eventually increases the frequency of the spontaneous nucleation of PLA crystals. Thus, when exposed to external stimuli such as UV light, PLA nanocomposite may show different structure alternation depending on the clay dispersion. Multiple-perturbation 2D correlation analysis of the PLA nanocomposite samples revealed different spatial variation between crystalline and amorphous structure of PLA, and the phenomenon especially becomes acute in the region where the clay particles are coagulated. The incorporation of the clay leads to the cleavage-induced crystallization of PLA when the sample is subjected to the UV light. The additional development of the ordered crystalline structure then works favorably to restrict the initial degradation of the polymer, providing the delay in the weight loss of the PLA.

  3. Efficient anti-tumor effect of photodynamic treatment with polymeric nanoparticles composed of polyethylene glycol and polylactic acid block copolymer encapsulating hydrophobic porphyrin derivative.

    Science.gov (United States)

    Ogawara, Ken-ichi; Shiraishi, Taro; Araki, Tomoya; Watanabe, Taka-ichi; Ono, Tsutomu; Higaki, Kazutaka

    2016-01-20

    To develop potent and safer formulation of photosensitizer for cancer photodynamic therapy (PDT), we tried to formulate hydrophobic porphyrin derivative, photoprotoporphyrin IX dimethyl ester (PppIX-DME), into polymeric nanoparticles composed of polyethylene glycol and polylactic acid block copolymer (PN-Por). The mean particle size of PN-Por prepared was around 80nm and the zeta potential was determined to be weakly negative. In vitro phototoxicity study for PN-Por clearly indicated the significant phototoxicity of PN-Por for three types of tumor cells tested (Colon-26 carcinoma (C26), B16BL6 melanoma and Lewis lung cancer cells) in the PppIX-DME concentration-dependent fashion. Furthermore, it was suggested that the release of PppIX-DME from PN-Por would gradually occur to provide the sustained release of PppIX-DME. In vivo pharmacokinetics of PN-Por after intravenous administration was evaluated in C26 tumor-bearing mice, and PN-Por exhibited low affinity to the liver and spleen and was therefore retained in the blood circulation for a long time, leading to the efficient tumor disposition of PN-Por. Furthermore, significant and highly effective anti-tumor effect was confirmed in C26 tumor-bearing mice with the local light irradiation onto C26 tumor tissues after PN-Por injection. These findings indicate the potency of PN-Por for the development of more efficient PDT-based cancer treatments.

  4. Monitoring Tumor Targeting and Treatment Effects of IRDye 800CW and GX1-Conjugated Polylactic Acid Nanoparticles Encapsulating Endostar on Glioma by Optical Molecular Imaging.

    Science.gov (United States)

    Li, Yaqian; Du, Yang; Liu, Xia; Zhang, Qian; Jing, Lijia; Liang, Xiaolong; Chi, Chongwei; Dai, Zhifei; Tian, Jie

    2015-01-01

    Molecular imaging used in cancer diagnosis and therapeutic response monitoring is important for glioblastoma (GBM) research. Antiangiogenic therapy currently is one of the emerging approaches for GBM treatment. In this study, a multifunctional nanoparticle was fabricated that can facilitate the fluorescence imaging of tumor and deliver a therapeutic agent to the tumor region in vivo and therefore possesses broad application in cancer diagnosis and treatment. This particle was polylactic acid (PLA) nanoparticles encapsulating Endostar, which was further conjugated with GX1 peptide and the near-infrared (NIR) dye IRDye 800CW (IGPNE). We demonstrated noninvasive angiogenesis targeting and therapy of IGPNE on U87MG xenografts in vivo using dual-modality optical molecular imaging including NIR fluorescence molecular imaging (FMI) and bioluminescence imaging (BLI). The NIR FMI results demonstrated that IGPNE had more accumulation to the tumor site compared to free IRDye 800CW. To further evaluate the antitumor treatment efficacy of IGPNE, BLI and immunohistochemistry analysis were performed on tumor-bearing mice. With the aid of molecular imaging, the results confirmed that IGPNE enhanced antitumor treatment efficacy compared to free Endostar. In conclusion, IGPNE realizes real-time imaging of U87MG tumors and improves the antiangiogenic therapeutic efficacy in vivo.

  5. Evaluation of periodontal healing in class Ⅱ furcation defects following guided tissue regeneration with two different types of polylactic acid membranes

    Institute of Scientific and Technical Information of China (English)

    Deniz Cetiner; Berrin (U)nsal; Ates Parlar; Elif Gültekin; Bülent Kurtis

    2004-01-01

    Background Guided tissue regeneration procedures provide predictable reconstruction of periodontal tissues in the treatment of furcation involvements in animals and huamns. This study was to compare long-term effectiveness of two different types of polylactic acid (PLA) membranes on periodontal regeneration in surgically created class Ⅱ furcation defects in dogs. Methods Full thickness mucoperiosteal flap was raised on the buccal aspects of the experimental teeth and class Ⅱ furcation defects having 5 mm vertical dimensions were created on mandibular premolar Ⅲ and IV on each quadrant. The exposed root sudaces were thoroughly planed and PLA membranes were placed over the experimental defects on both sites. One site received liquid polymer membrane (LPM), and resorbable periodontal mesh (RPM) membranes were applied to the other site. The animals were sacrificed at 7 months after surgery and the specimens were processed for histological evaluation. Results The average length of new attachment formed on the treated roots in both groups ranged from 3. 02mm to 4.5mm. Complete bone filling was observed at the furcation sites. No statistically significant differences were found between two membranes in any of the parameters (P>0. 05). Conclusion This study demonstrates favorable regenerative outcomes by the use of two different types of PLA membranes that could be used as alternatives for guided tissue regeneration (GTR).

  6. Versatile Biodegradable Poly(ester amides Derived from α-Amino Acids for Vascular Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Pooneh Karimi

    2010-03-01

    Full Text Available Biodegradable poly(ester amide (PEA biomaterials derived from α-amino acids, diols, and diacids are promising materials for biomedical applications such as tissue engineering and drug delivery because of their optimized properties and susceptibility for either hydrolytic or enzymatic degradation. The objective of this work was to synthesize and characterize biodegradable PEAs based on the α-amino acids L-phenylalanine and L-methionine. Four different PEAs were prepared using 1,4-butanediol, 1,6-hexanediol, and sebacic acid by interfacial polymerization. High molecular weight PEAs with narrow polydispersity indices and excellent film-forming properties were obtained. The incubation of these PEAs in PBS and chymotrypsin indicated that the polymers are biodegradable. Human coronary artery smooth muscle cells were cultured on PEA films for 48 h and the results showed a well-spread morphology. Porous 3D scaffolds fabricated from these PEAs were found to have excellent porosities indicating the utility of these polymers for vascular tissue engineering.

  7. Oleanolic Acid Delivery using Biodegradable Nanoparticles for Cancer Therapy

    OpenAIRE

    Man, KWD; Kwok, PCL; Lam, JKW

    2014-01-01

    Oleanolic acid (OA) is a naturally occurring pentacyclic triterpenoid widely found in Chinese herbs. It has been extensively studied owing to the beneficial effects such as hepatoprotection, anti-inflammatory and it is recently found to have anti-tumor ability. However, resembling the other hydrophobic drugs, it has poor water solubility and therefore very limited intestinal absorption when administrated orally. Investigations concerning the delivery of OA have been ...

  8. Biodegradation of naphtalenesulphonic acid-containing sewages in a two-stage treatment plant

    Energy Technology Data Exchange (ETDEWEB)

    Krull, R. (Paderborn Univ. (Gesamthochschule) (Germany). Technische Chemie und Chemische Verfahrenstechnik); Hempel, D.C. (Paderborn Univ. (Gesamthochschule) (Germany). Technische Chemie und Chemische Verfahrenstechnik)

    1994-05-01

    The production of naphthol the coupling compound in the syntheses of azo-dyes occurs a naphthalenesulphonic acid-containing wastewater. The aerobic biodegradation of a complex mixture of naphthalenemono- and -disulphonic acids with high amounts of inorganic salts was examined in a two-stage plant with specially adapted and immobilized microorganisms fixed on broken sand particles. The plant consists of two airlift-loop reactors. An interposed settling tank separates the two different bacterial communities in the stages. In the first stage the sequential metabolization of naphthalene-2- and -1-sulphonic acid was achieved by strain Pseudomonas testosteroni A[sub 3] at residence times down to 1.5 h. The total degradation of remaining naphthalene-1-sulphonic acid and the degradation of recalcitrant naphthalenedisulphonic acids was obtained by a defined mixed culture in the second unit. Because of the more recalcitrant character of the remaining components in the second stage examinations with Na[sub 2]SO[sub 4]-loaded and salt-free wastewater were carried out at mean residence times between 50 and 6.3 h. With salt-loaded sewage an overall degradation of approximately 71% was achieved. The main component in the effluent was non-biodegradable naphthalene-1.5-disulphonic acid. Investigations with salt-free wastewater have shown an increasing overall degradation up to 84%. Thus, in the presence of inorganic salts a considerable inhibition of the biological degradation of the recalcitrant substances in the second unit was found. (orig.)

  9. Anaerobic Biodegradation of Tetrachloroethylene with Acetic Acid as Cometabolism Substrate under Anaerobic Condition

    Institute of Scientific and Technical Information of China (English)

    LI Ye; LIU Fei; CHEN Honghan; SHI Jinhua; WANG Yufan

    2008-01-01

    A series of batch-type experiments with acetate acid as the primary substrate wereperformed using enrichment cultures developed from the anaerobic sludge to investigate the effect ofacetate acid on tetrachloroethylene (PCE) biodegradation. Experimental results indicated that acetateacid was an efficient electron donor in affecting the biotransformability of PCE. Trichloroethylene(TCE) was the primary dehalogenation product, and small amounts of dichloroethylenes (DCEs) werealso detected. No significant further DCEs degradation was detected. PCE degradation rate in theexperiment was 36.6 times faster than background rate in natural groundwater.

  10. Genotoxic and antibutyrylcholinesterasic activities of acid violet 7 and its biodegradation products.

    Science.gov (United States)

    Mansour, Hedi Ben; Mosrati, Ridha; Limem, Ilef; Corroler, David; Ghedira, Kamel; Barillier, Daniel; Chekir-Ghedira, Leila

    2009-01-01

    Acid violet 7, a sulfonated azo dye was degraded by Pseudomonas putida mt-2 in mineral medium at concentrations up to 200 mg/L. The genotoxicity of AV7 and its biodegradation extracts was evaluated by using the DNA-strand scission assay. No genotoxicity was observed, even with or without exposition to UV irradiation, for biodegradation under shaking conditions, but increased significantly after biodegradation under static conditions. In addition, the ability of tested compounds to reduce human plasma butyrylcholinesterase (BuChE) activity was evaluated in vitro. Genotoxicity and anti-BuChE activity generated by the azoreduction products [4'-aminoacetanilid (4'-AA) and 5-acetamido-2-amino-1-hydroxy-3,6-naphtalene disulfonic acid (5-ANDS)] were assessed and compared with that of the parent unsubstituted amines. 4'-AA exhibited a strong genotoxicity, which was imputed to the presence of the acetoxy (COCH3) substituent on the aromatic amine; however, the presence of sulphonic groups in 5-ANDS seems to be responsible for its BuChE inhibition activity. The present study demonstrates that P. putida mt-2, incubated under aerobic conditions, has a catabolism that enables it to degrade AV7 and, especially, to detoxify the dye mixtures.

  11. Study on double-end hydroxyl poly(lactic acid) with controlled polymerization degree by condensation%聚合度可控的双端羟聚乳酸的缩聚合成研究

    Institute of Scientific and Technical Information of China (English)

    吴传保; 孙平; 刘祥丽; 曾湘晖; 刘利江

    2013-01-01

    In order to explore the method of regulating poly(lactic acid) polymerization degree and end group type in the process of lactic acid direct polycondensation,and open up new areas of synthesizing poly(lactic acid)-based functional polymers by direct polycondensation,glycol was selected as examples to study lactic acid direct polycondensation under the conditions of adding diols.1H NMR was used to characterize product structure and viscosity and mass determinations were used to track reaction process.Experimental results show that the addition of glycol is useful to regulate the polymerization degree of poly(lactic acid) due to changing relative amount of hydroxyl and carboxyl functional groups.The method of calculating theoretical polymerization degree of poly(lactic acid) was obtained through experimental study.This study provides preliminary research basis for improving direct polycondensation method to obtain poly (lactic acid) with particular polymerization degree and increase control accuracy of polymerization degree.%为了探索在乳酸直接缩聚过程中调控聚合度及端基类型的方法和开辟通过直接缩聚合成聚乳酸基功能高分子的新领域,以乙二醇为例,对二元醇存在条件下的乳酸直接缩聚进行了研究.通过1H NMR对产物的结构进行了表征,通过测定质量及黏度对反应过程进行了跟踪.实验结果表明,加入乙二醇后,由于羟基与羧基官能团相对量的改变,对聚乳酸聚合度具有调控作用.通过实验研究得出了添加乙二醇条件下的理论聚合度的计算方法.本研究为通过直接缩聚合成具有特定聚合度的遥爪型聚乳酸大分子单体,进而合成聚乳酸基功能高分子奠定了基础.

  12. Impact of acid and oxidative modifications, single or dual, of sorghum starch on biodegradable films.

    Science.gov (United States)

    Biduski, Bárbara; Silva, Francine Tavares da; Silva, Wyller Max da; Halal, Shanise Lisie de Mello El; Pinto, Vania Zanella; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2017-01-01

    The objective of this study was to evaluate the effects of acid and oxidation modifications on sorghum starch, as well as the effect of dual modification of starch on the physical, morphological, mechanical, and barrier properties of biodegradable films. The acid modification was performed with 3% lactic acid and the oxidation was performed with 1.5% active chlorine. For dual modification, the acid modification was performed first, followed by oxidation under the same conditions as above. Both films of the oxidized starches, single and dual, had increased stiffness, providing a higher tensile strength and lower elongation when compared to films based on native and single acid modified starches. However, the dual modification increased the water vapor permeability of the films without changing their solubility. The increase in sorghum starch concentration in the filmogenic solution increased the thickness, water vapor permeability, and elongation of the films. PMID:27507447

  13. Cross-linked, biodegradable, cytocompatible salicylic acid based polyesters for localized, sustained delivery of salicylic acid: an in vitro study.

    Science.gov (United States)

    Chandorkar, Yashoda; Bhagat, Rajesh K; Madras, Giridhar; Basu, Bikramjit

    2014-03-10

    In order to suppress chronic inflammation while supporting cell proliferation, there has been a continuous surge toward development of polymers with the intention of delivering anti-inflammatory molecules in a sustained manner. In the above backdrop, we report the synthesis of a novel, stable, cross-linked polyester with salicylic acid (SA) incorporated in the polymeric backbone and propose a simple synthesis route by melt condensation. The as-synthesized polymer was hydrophobic with a glass transition temperature of 1 °C, which increases to 17 °C upon curing. The combination of NMR and FT-IR spectral techniques established the ester linkages in the as-synthesized SA-based polyester. The pH-dependent degradation rate and the rate of release of salicylic acid from the as-synthesized SA-based polymer were studied at physiological conditions in vitro. The polyester underwent surface erosion and exhibited linear degradation kinetics in which a change in degradation rate is observed after 4-10 days and 24% mass loss was recorded after 4 months at 37 °C and pH 7.4. The delivery of salicylic acid also showed a similar change in slopes, with a sustained release rate of 3.5% in 4 months. The cytocompatibility studies of these polyesters were carried out with C2C12 murine myoblast cells using techniques like MTT assay and flow cytometry. Our results strongly suggest that SA-based polyester supports cell proliferation for 3 days in culture and do not cause cell death (salicylic acid and have applications in adjuvant cancer therapy, chronic wound healing, and as an alternative to commercially available polymers like poly(lactic acid) and poly(glycolic acid) or their copolymers.

  14. Mandibular bone repair by implantation of rhBMP-2 in a slow release carrier of polylactic acid--an experimental study in rats.

    Science.gov (United States)

    Schliephake, Henning; Weich, Herbert A; Dullin, Christian; Gruber, Rudolf; Frahse, Sarah

    2008-01-01

    The aim of the present study was to test the hypothesis that human recombinant bone morphogenic protein 2 (rhBMP-2) implanted in a slow release carrier of polylactic acid (PLA) can repair a non-healing defect in the rat mandible and maintain the thickness of an augmented volume. p-DL-lactic acid discs were produced and loaded with 48 and 96 microg rhBMP-2 and inserted into non-healing defects of the mandible of 45 Wistar rats. Fifteen rats received implants with 96 microg rhBMP-2 (Group 2), 48 microg rhBMP-2 (Group 1) and blank implants without BMP (Group 0) each on one side of the mandible. Unfilled defects of the same size on the contralateral sides of the mandibles served as empty controls. After 6, 13 and 26 weeks, implants of each group were retrieved from five animals each and submitted to flat panel detector computed tomography. Bone formation and thickness of augmentation was assessed by computer-assisted histomorphometry. In Group 2 significantly more bone was produced than in Group 1. Implants of Group 1 induced significantly more bone than the blank controls only after 6 weeks, whereas the difference was not significant after 13 and 26 weeks. Differences between Group 2 and Group 1 were clearly significant after 26 weeks. The thickness of bone tissue was maintained in Group 2 whereas it decreased in Group 1 and was negligible in Group 0. It is concluded that the PLA implants with 96 microg rhBMP-2 were able to bridge a non-healing defect in the rat mandible and maintained the thickness of an augmented volume. However, continuous supply of osteogenic signals appears to be required to compensate for adverse effects during polymer degradation. PMID:17936352

  15. Preparation and characterizations of cellulose-polylactic acid blending material%纤维素-聚乳酸共混改性膜材料的制备及其性能的研究

    Institute of Scientific and Technical Information of China (English)

    肖舒; 戴林; 申越; 何静

    2011-01-01

    将微晶纤维素溶于离子液体中,加入不同质量的聚乳酸,配制成共混溶液并成膜。通过红外光谱对其结构进行测定,证明共混物制备成功。X-衍射、SEM及DSC测试结果表明,共混物之间具有较好的相容性,当微晶纤维素与聚乳酸的质量比为60:40时共混效果较好,较易成膜,且二者的结晶过程得到互相促进,结晶完美度及晶体尺寸提高。同时,DSC测试结果表明,不同质量比的纤维素-聚乳酸共混物具有不同的结晶度,且纤维素与聚乳酸的质量比为60:40时亦具有较好的化学及生物降解性。%The cellulose-polylactie acid blending membrane was prepared via mixed solvent method.Firstly, microcrystalline cellulose was dissolved in ionic liquid,and then a different quality of polylactic acid was added. Infrared spectroscopy(FTIR) determined that blending membrane was prepared successfully.According to the results of X-ray diffraction,SEM and DSC,the microcrystalline cellulose and polylactic acid showed good compatibility with each other.When the mass ratio of microcrystalline cellulose to polylactic acid was 60:40,the membrane was easily obtained.At the same time,the crystallization process was promoted,and crystallization degree and crystal size were also increased.The results of DSC also showed that different mass ratio of cellulosepolylactic acid membrane had different degree of crystallinity.When the mass ratio of microcrystalline cellulose to polylactic acid was 60:40,the membrane also had good chemical and biological degradation.

  16. Biodegradation of naphthenic acid surrogates by axenic cultures.

    Science.gov (United States)

    Yue, Siqing; Ramsay, Bruce A; Ramsay, Juliana A

    2015-07-01

    This is the first study to report that bacteria from the genera Ochrobactrum, Brevundimonas and Bacillus can be isolated by growth on naphthenic acids (NAs) extracted from oil sands process water (OSPW). These pure cultures were screened for their ability to use a range of aliphatic, cyclic and aromatic NA surrogates in 96-well microtiter plates using water-soluble tetrazolium redox dyes (Biolog Redox Dye H) as the indicator of metabolic activity. Of the three cultures, Ochrobactrum showed most metabolic activity on the widest range of NA surrogates. Brevundomonas and especially Ochrobactrum had higher metabolic activity on polycyclic aromatic compounds than other classes of NA surrogates. Bacillus also oxidized a wide range of NA surrogates but not as well as Ochrobactrum. Using this method to characterize NA utilisation, one can identify which NAs or NA classes in OSPW are more readily degraded. Since aromatic NAs have been shown to have an estrogenic effect and polycyclic monoaromatic compounds have been suggested to pose the greatest environmental threat among the NAs, these bacterial genera may play an important role in detoxification of OSPW. Furthermore, this study demonstrates that bacteria belonging to the genera Ochrobactrum and Bacillus can also degrade surrogates of tricyclic NAs.

  17. Research on effect of chitosan-polylactic acid film on rabbit colonic fistula for primary repair%壳聚糖聚乳酸膜的兔结肠瘘一期修复实验研究

    Institute of Scientific and Technical Information of China (English)

    曾志华; 陈康; 李瑛; 谢良宪

    2011-01-01

    Objective: To compare therapeutic effects of chitosan-polylactic acid film on rabbit colonic fistula. Methods-. Poly lactic acid film(PAF) and chitosan-polylactic acid film(CPAF) were prepared.The rabbits were divided equally into three groups for different treatments (PAF group,CPAF group,control group),purse string suture following colon stoma.After such disposition,PAF group and CPAF group covered the suture with PAF and CPAF respectively,while control group did nothing.Rabbits were parallel observed and detected with immunohistochemical staining for TGF-β1 after 20 days. Results:Physical characteristic had no statistics difference between PAF and CPAF.Rabbits in PAF and CPAF group all survived,but in control group were dead within 7 days.Immunohisto-chemical staining for TGF-β1 had obviously smaller amount in CPAF than in PAF and control group,and PAF also smaller than control group.Statistics difference was observed.CPAF had more inhibition in TGF-β1 than the other two group and the results were significant difference. Conclusion :CPAF had better therapeutic efficacy than PAF on colonic fistula.%目的:研究壳聚糖聚乳酸膜(Chitosan-polylactic acid film,CPAF)对兔结肠瘘的一期治疗效果.方法:制备聚乳酸膜(Polylactic acid film,PAF)和CPAF.新西兰大耳白兔24只,均分3组予以不同的处理(PAF组、CPAF组、对照组),结肠造瘘后荷包缝合,其中PAF组予以PAF覆盖缝合,CPAF组予以CPAF覆盖缝合,对照组不作其他处理,平行观察,20d后处死动物作免疫组化检测转移生长因子β1(Transforming growth factor,TGF-β1).结果:PAF和CPAF的物理特性无统计学差异.PAF组和CPAF组动物全部存活,对照组动物7d内死亡.TGF-β1免疫组化染色CPAF组明显少于PAF组和对照组,PAF组明显少于对照组,结果有统计学差异.CPAF组对TGF-β1的抑制作用强于PAF组和对照组,结果差异显著.结论:CPAF对兔结肠瘘的一期治疗效果优于PAF.

  18. Biodegradation of starch–graft–polystyrene and starch–graft–poly(methacrylic acid) copolymers in model river water

    OpenAIRE

    Nikolić Vladimir; Veličković Sava; Antonović Dušan; Popović Aleksandar

    2013-01-01

    In this paper the biodegradation study of grafted copolymers of polystyrene (PS) and corn starch and poly(methacrylic acid) and corn starch in model river water is described. These copolymers were obtained in the presence of different amine activators. The synthesized copolymers and products of degradation were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Biodegradation was monitored by mass decrease and number of microorganisms...

  19. Atrazine biodegradation modulated by clays and clay/humic acid complexes

    International Nuclear Information System (INIS)

    The fate of pesticides in the environment is strongly related to the soil sorption processes that control not only their transfer but also their bioavailability. Cationic (Ca-bentonite) and anionic (Layered Double Hydroxide) clays behave towards the ionisable pesticide atrazine (AT) sorption with opposite tendencies: a noticeable sorption capacity for the first whereas the highly hydrophilic LDH showed no interactions with AT. These clays were modified with different humic acid (HA) contents. HA sorbed on the clay surface and increased AT interactions. The sorption effect on AT biodegradation and on its metabolite formation was studied with Pseudomonas sp. ADP. The biodegradation rate was greatly modulated by the material's sorption capacity and was clearly limited by the desorption rate. More surprisingly, it increased dramatically with LDH. Adsorption of bacterial cells on clay particles facilitates the degradation of non-sorbed chemical, and should be considered for predicting pesticide fate in the environment. - The biodegradation rate of atrazine was greatly modulated by adsorption of the pesticide and also bacterial cells on clay particles.

  20. Optimization of process parameters for enhanced biodegradation of acid red 119 by Bacillus thuringiensis SRDD

    Directory of Open Access Journals (Sweden)

    Riddhi H. Dave

    2012-02-01

    Full Text Available Developed Bacillus thuringiensis SRDD showed degradation of C.I. Acid red 119 and growth under the extremecondition of temperature 70°C, pH 3-8, heavy metals concentration of 0.8 mM, NaCl up to 900 mM and 1000 ppm dye. Cottonseed, caster cake and corn cake powders were found to be better and cheaper nutrient supplements for the Bacillus thuringiensisSRDD for biodegradation as compared to molasses. After development of the culture and the process, more than99% degradation was achieved in less than 2 hrs of contact time even on 18th cycles of addition of 100 ppm AR-119 dye. Thedeveloped process showed AR-119 biodegradation rate as high as 220 mg L-1 h-1, which is found to be 130 times more ascompared to the reported data. U.V., FTIR, TLC and HPLC analysis data confirmed biodegradation ability of the Bacillusthuringiensis for AR-119.

  1. Bony defect repair in rabbit using hybrid rapid prototyping polylactic co glycolic acid/β tricalciumphosphate collagen I/apatite scaffold and bone marrow mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Long Pang

    2013-01-01

    Full Text Available Background: In bone tissue engineering, extracellular matrix exerts critical influence on cellular interaction with porous biomaterial and the apatite playing an important role in the bonding process of biomaterial to bone tissue. The aim of this study was to observe the therapeutic effects of hybrid rapid prototyping (RP scaffolds comprising polylactic-co-glycolic acid (PLGA, β-tricalciumphosphate (β-TCP, collagen I and apatite (PLGA/β-TCP-collagen I/apatite on segmental bone defects in conjunction with combination with bone marrow mesenchymal stem cells (BMSCs. Materials and Methods: BMSCs were seeded into the hybrid RP scaffolds to repair 15 mm defect in the radius of rabbits. Radiograph, microcomputed tomography and histology were used to evaluate new bone formation. Results: Radiographic analysis done from 12 to 36 weeks postoperative period demonstrated that new bone formed at the radial defect site and continues to increase until the medullary cavity is recanalized and remodelling is complete. The bone defect remained unconnected in the original RP scaffolds (PLGA/β-TCP during the whole study. Histological observations conformed to the radiographic images. In hybrid RP scaffold group, woven bone united the radial defect at 12 weeks and consecutively remodeled into lamellar bone 24 weeks postoperation and finally matured into cortical bone with normal marrow cavity after another 12 weeks. No bone formation but connective tissue has been detected in RP scaffold at the same time. Conclusion: Collagen I/apatite sponge composite coating could improve new bone formation in vivo. The hybrid RP scaffold of PLGA/β-TCP skeleton with collagen I/apatite sponge composite coating is a promising candidate for bone tissue engineering.

  2. Bioactivity of CaSiO3/poly-lactic acid (PLA) composites prepared by various surface loading methods of CaSiO3 powder.

    Science.gov (United States)

    Okada, Kiyoshi; Hasegawa, Fumikazu; Kameshima, Yoshikazu; Nakajima, Akira

    2007-05-01

    Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO(3)/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO(3) powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA substrate in method (2). In method (3), CaSiO(3) powder was surface loaded on to a PLA substrate by hot pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 microm after soaking for 14 days. Since the amount of CaSiO(3) powder used in these samples was only ceramic powder. PMID:17216578

  3. Tacticity-induced changes in the micellization and degradation properties of poly(lactic acid)-block-poly(ethylene glycol) copolymers.

    Science.gov (United States)

    Agatemor, Christian; Shaver, Michael P

    2013-03-11

    Poly(lactic acid)-block-poly(ethylene glycol) copolymers (PLA-b-PEG) featuring varying tacticities (atactic, heterotactic, isotactic) in the PLA block were synthesized and investigated for their micellar stability, degradation, and thermal properties. Utilizing tin(II) bis(2-ethylhexanoate), aluminum salan, and aluminum salen catalysts, the copolymers were synthesized through the ring-opening polymerization of d-, l-, rac-, or a blend of l- and rac-lactide using monomethoxy-poly(ethylene glycol) as a macroinitiator. The critical micelle concentration, which reflects the micellar stability, was probed using a fluorescence spectroscopic method with pyrene as the probe. The copolymers were degraded in a methanolic solution of 1,5,7-triaza-bicyclo[4.4.0]dec-5-ene and the degradation was measured by (1)H NMR spectroscopic and gel permeation chromatographic analyses. Differential scanning calorimetry and thermogravimetric analysis provided information on the thermal properties of the copolymers. Atactic and heterotactic microstructures in the PLA block resulted in lower micellar stability, as well as faster degradation and shorter erosion time compared to polymers with high isotactic enchainment (Pm). By modification of the Pm, micellar stability, degradation, and erosion rates of the copolymers can be tuned to specific biomedical applications. Interestingly, while tin(II) bis(2-ethylhexanoate) and aluminum salan-catalyzed PLA-b-PEG copolymers exhibited similar micellization behavior, the aluminum salen-catalyzed PLA-b-PEG exhibited unique behavior at high micelle concentration in the presence of the pyrene probe. This unique behavior can be attributed to the disintegration of the micelles through the interactions of long isotactic stereoblock segments. PMID:23402292

  4. Fabrication of novel high performance ductile poly(lactic acid) nanofiber scaffold coated with poly(vinyl alcohol) for tissue engineering applications.

    Science.gov (United States)

    Abdal-Hay, Abdalla; Hussein, Kamal Hany; Casettari, Luca; Khalil, Khalil Abdelrazek; Hamdy, Abdel Salam

    2016-03-01

    Poly(lactic acid) (PLA) nanofiber scaffold has received increasing interest as a promising material for potential application in the field of regenerative medicine. However, the low hydrophilicity and poor ductility restrict its practical application. Integration of hydrophilic elastic polymer onto the surface of the nanofiber scaffold may help to overcome the drawbacks of PLA material. Herein, we successfully optimized the parameters for in situ deposition of poly(vinyl alcohol), (PVA) onto post-electrospun PLA nanofibers using a simple hydrothermal approach. Our results showed that the average fiber diameter of coated nanofiber mat is about 1265±222 nm, which is remarkably higher than its pristine counterpart (650±180 nm). The hydrophilicity of PLA nanofiber scaffold coated with a PVA thin layer improved dramatically (36.11±1.5°) compared to that of pristine PLA (119.7±1.5°) scaffold. The mechanical testing showed that the PLA nanofiber scaffold could be converted from rigid to ductile with enhanced tensile strength, due to maximizing the hydrogen bond interaction during the heat treatment and in the presence of PVA. Cytocompatibility performance of the pristine and coated PLA fibers with PVA was observed through an in vitro experiment based on cell attachment and the MTT assay by EA.hy926 human endothelial cells. The cytocompatibility results showed that human cells induced more favorable attachment and proliferation behavior on hydrophilic PLA composite scaffold than that of pristine PLA. Hence, PVA coating resulted in an increase in initial human cell attachment and proliferation. We believe that the novel PVA-coated PLA nanofiber scaffold developed in this study, could be a promising high performance biomaterial in regeneration medicine. PMID:26706517

  5. 葫芦素毫微粒冻干针剂的研究%A Study on Lyophilization Injection of Cucurbitacin Polylactic Acid Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    李超英; 侯世祥; 阳长明; 孙毅毅; 张继芬

    2001-01-01

    目的:制备稳定的、易再分散的葫芦素聚乳酸毫微粒(Cu-PLA-NP)冻干针剂。方法:选用适宜填充剂制备Cu-PLA-NP冻干针剂,并评价其相关理化性质。结果:冻干前后毫微粒形态、粒径、pH、包封率及载药量无明显变化,再分散性良好,制剂稳定,含水量合格。其临界相对湿度为69.52%。结论:在适宜的处方及工艺条件下制备的Cu-PLA-NP冻干针剂是可行的。%Objective:To prepare stable and redispersable Lyophilization injection of cucurbitacin polylactic acid nanoparticles(Cu-PLA-NP).Method:An optimal supporting agent was chosen to prepare the Cu-PLA-NP lyophilization injection.The physical and chemical properties of the injection were evaluated.Result:The shape,diameters,association ratio,drug loading and pH of Cu-PLA-NP colloidal solution and lyophilization injection were not changed.The content of water consisted with the requirement of lyophilization injection.The critical relative humidity was 69.52%.The stability was good.Conclusion:It is practicable to prepare Cu-PLA-NP lyophilization injection with proper formulas and preparation processes.

  6. Novel electrospun nanofibrous matrices prepared from poly(lactic acid)/poly(butylene adipate) blends for controlled release formulations of an anti-rheumatoid agent.

    Science.gov (United States)

    Siafaka, Panoraia I; Barmbalexis, Panagiotis; Bikiaris, Dimitrios N

    2016-06-10

    In the present work, a series of novel formulations consisting of poly(lactic acid)/poly(butylene adipate) (PLA/PBAd) electrospun blends was examined as controlled release matrices for Leflunomide's active metabolite, Teriflunomide (TFL). The mixtures were prepared using different ratios of PLA and PBAd in order to produce nanofibrous matrices with different characteristics. Miscibility studies of the blended polymeric fibers were performed through differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). Hydrolytic degradation in the prepared fibers was evaluated at 37°C using a phosphate buffered saline solution. Different concentrations of (TFL) (5, 10, 15wt.%) were incorporated into nanofibers for examining the drug release behavior in simulated body fluids (SBF), at 37°C. The drug-loaded nanofibrous formulations were further characterized by Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy, DSC and XRD. Gel permeation chromatography (GPC) analysis was used to evaluate the mechanism of TFL release. Artificial neural networks (ANN) and multi-linear-regression (MLR) models were used to evaluate the effect of % content of PBAd (X1) and TFL (X2) on an initial burst effect and a dissolution behavior. It was found that PLA/PBAd nanofibers have different diameters depending on the ratio of used polyesters and added drug. TFL was incorporated in an amorphous form inside the polymeric nanofibers. In vitro release studies reveal that a drug release behavior is correlated with the size of the nanofibers, drug loading and matrix degradation after a specific time. ANN dissolution modeling showed increased correlation efficacy compared to MLR. PMID:27039136

  7. Bioactivity of CaSiO3/poly-lactic acid (PLA) composites prepared by various surface loading methods of CaSiO3 powder.

    Science.gov (United States)

    Okada, Kiyoshi; Hasegawa, Fumikazu; Kameshima, Yoshikazu; Nakajima, Akira

    2007-08-01

    Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO(3)/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO(3) powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA substrate in method (2). In method (3), CaSiO(3) powder was surface loaded on to a PLA substrate by hot-pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 microm after soaking for 14 days. Since the amount of CaSiO(3) powder used in these samples was only polymer-matrix composites by loading with only very small amounts of ceramic powder. PMID:17483882

  8. Degradation of polylactic acid (Pla) at different doses of gamma radiation; Degradacion del acido polilactico (PLA) a diferentes dosis de radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Castillo R, Y.

    2015-07-01

    The excessive use of polymers such as polyethylene (PET), polystyrene (Ps) and recently the polylactic acid (Pla) that take more than 20 years to degrade, have caused great pollution in the environment. In this study the effects of gamma radiation in the Pla to different doses were studied, in order to reduce the degradation time of this polymer. The changes in physico-chemical structure of Pla during radiation were studied by thermo-gravimetric/Mass analysis; differential scanning calorimetry; scanning electron microscopy; X-ray dispersive analysis; infrared spectroscopy; X-ray diffraction and mechanical tests of hardness, elasticity and deformation. With scanning electron microscopy, the morphology of the Pla surface unirradiated was observed, in which an apparently smooth surface was observed, after changes that had the Pla when irradiated also was observed, where the effects of radiation were observed in form of scratch, agglomeration and small fractures. By X-ray dispersive analysis was determined and verified the elemental chemical composition of the Pla; as expected the tests showed only carbon, oxygen and hydrogen. With thermo-gravimetric/Mass analysis the decomposition temperatures of Pla were determined, identifying that the degradation compounds are CO, CO{sub 2} and CH{sub 4}. With infrared spectrometry the major peaks of Pla were observed before and after being irradiated with increasing of radiation dose the intensity of the bands decreased. Also by X-ray diffraction was observed that the polymer is an amorphous material. The mechanical tests indicate that the values of each of the tests decrease significantly with increasing the radiation dose. (Author)

  9. Polyethylene glycol–polylactic acid nanoparticles modified with cysteine–arginine–glutamic acid–lysine–alanine fibrin-homing peptide for glioblastoma therapy by enhanced retention effect

    Directory of Open Access Journals (Sweden)

    Wu J

    2014-11-01

    Full Text Available Junzhu Wu,1,2,* Jingjing Zhao,1,3,* Bo Zhang,1 Yong Qian,1 Huile Gao,1 Yuan Yu,1 Yan Wei,1 Zhi Yang,1 Xinguo Jiang,1 Zhiqing Pang1 1Key Laboratory of Smart Drug Delivery, Ministry of Education, Department of Pharmaceutics, School of Pharmacy, Fudan University, Shanghai, 2School of Pharmacy, Dali University, Xiaguan, 3School of Pharmacy, China Pharmaceutical University, Nanjing, People’s Republic of China *These authors contributed equally to this work Abstract: For a nanoparticulate drug-delivery system, crucial challenges in brain-glioblastoma therapy are its poor penetration and retention in the glioblastoma parenchyma. As a prevailing component in the extracellular matrix of many solid tumors, fibrin plays a critical role in the maintenance of glioblastoma morphology and glioblastoma cell differentiation and proliferation. We developed a new drug-delivery system by conjugating polyethylene glycol–polylactic acid nanoparticles (NPs with cysteine–arginine–glutamic acid–lysine–alanine (CREKA; TNPs, a peptide with special affinity for fibrin, to mediate glioblastoma-homing and prolong NP retention at the tumor site. In vitro binding tests indicated that CREKA significantly enhanced specific binding of NPs with fibrin. In vivo fluorescence imaging of glioblastoma-bearing nude mice, ex vivo brain imaging, and glioblastoma distribution demonstrated that TNPs had higher accumulation and longer retention in the glioblastoma site over unmodified NPs. Furthermore, pharmacodynamic results showed that paclitaxel-loaded TNPs significantly prolonged the median survival time of intracranial U87 glioblastoma-bearing nude mice compared with controls, Taxol, and NPs. These findings suggested that TNPs were able to target the glioblastoma and enhance retention, which is a valuable strategy for tumor therapy. Keywords: CREKA peptide, nanoparticles, retention effect, paclitaxel, glioblastoma

  10. The effect of AZD2171- or sTRAIL/Apo2L-loaded polylactic-co-glycolic acid microspheres on a subcutaneous glioblastoma model.

    Science.gov (United States)

    Shivinsky, Anna; Bronshtein, Tomer; Haber, Tom; Machluf, Marcelle

    2015-08-01

    Studies with AZD2171-a new anti-angiogenic inhibitor of tyrosine kinases associated with VEGF signaling-have shown great promise for treating glioblastoma. Unfortunately, AZD2171 success is limited by low permeability through the blood-brain barrier. Due to AZD2171's short half-life and high toxicity, its local administration will require multiple intracranial procedures, making this approach clinically unfeasible. In this study, we investigated the potential of the highly hydrophobic AZD2171, released from modified polylactic-co-glycolic acid microspheres (PLGA-MS), to treat glioblastoma. To further demonstrate the versatile loading capacity of this system, the same PLGA formulation, which was found optimal for the loading and release of AZD2171, was tested with sTRAIL/Apo2L-a biologic drug that is very different than AZD2171 in its molecular weight, solubility, and charge. AZD2171 released from PLGA-MS was at least effective as the free drug in inhibiting endothelial growth and proliferation (in vitro), and, surprisingly, had a profound cytotoxic effect also towards in vitro cultured glioblastoma cell-lines (U87 and A172). Complete tumor inhibition was achieved following a single treatment with AZD2171-loaded PLGA-MS (6 (mg)/kg) administered locally adjacent to human U87 glioma tumors inoculated subcutaneously in nude mice. This improved effect, compared to other therapeutic approaches involving AZD2171, was shown to affect both tumor vasculature and the glioma cells. sTRAIL-loaded microspheres, administered at very low doses (0.3 (mg)/kg), led to 35 % inhibition of tumor growth in 2 weeks. Collectively, our results provide pre-clinical evidence for the potential of PLGA formulations of AZD2171 and sTRAIL to serve as an effective treatment for glioblastoma.

  11. 3D-printed polylactic acid supports for enhanced ionization efficiency in desorption electrospray mass spectrometry analysis of liquid and gel samples.

    Science.gov (United States)

    Elviri, Lisa; Foresti, Ruben; Bianchera, Annalisa; Silvestri, Marco; Bettini, Ruggero

    2016-08-01

    The potential of 3D printing technology was here exploited to prepare tailored polylactic acid (PLA) supports for desorption electrospray ionization (DESI) experiments. PLA rough solid supports presenting wells of different shape (i.e. cylindrical, cubic and hemispherical cavities) were designed to accommodate samples of different physical state. The potentials of such supports in terms of sample loading capacity, sensitivity, signal stability were tested by analysing a peptide (i.e. insulin) and an aminoglycoside antibiotic (i.e. gentamicin sulphate) from solution and a chitosan-based gel. The results obtained were compared with those obtained by using a traditional polytetrafluoroethylene (PTFE) support and discussed. By using PLA support on the flat side, signal intensity improved almost twice with respect to PTFE support, whereas with spherical wells a five times improved signal sensitivity and good stability (RSD<6%) were obtained for the analysis of two model molecules. Limits of detection were in the 3-10nM range and linearity was demonstrated for both analytes in the 0.05-0.5μM range for semi-quantitative or quantitative purposes. The use of a well and the set-up of optimal source parameters allowed the analysis of samples in a gel state with good precision (RSD<10%) and accuracy (86±6-102±9%), otherwise difficult to analyse on a flat smooth surface. These findings are of great interest and stimulus to exploit the advantages of 3D printing technology for the development of devices for a DESI source, presenting different shapes or configuration as a function of the sample types.

  12. Surface modification of biomaterials based on high-molecular polylactic acid and their effect on inflammatory reactions of primary human monocyte-derived macrophages: perspective for personalized therapy.

    Science.gov (United States)

    Stankevich, Ksenia S; Gudima, Alexandru; Filimonov, Victor D; Klüter, Harald; Mamontova, Evgeniya M; Tverdokhlebov, Sergei I; Kzhyshkowska, Julia

    2015-06-01

    Polylactic acid (PLA) based implants can cause inflammatory complications. Macrophages are key innate immune cells that control inflammation. To provide higher biocompatibility of PLA-based implants with local innate immune cells their surface properties have to be improved. In our study surface modification technique for high-molecular PLA (MW=1,646,600g/mol) based biomaterials was originally developed and successfully applied. Optimal modification conditions were determined. Treatment of PLA films with toluene/ethanol=3/7 mixture for 10min with subsequent exposure in 0.001M brilliant green dye (BGD) solution allows to entrap approximately 10(-9)mol/cm(2) model biomolecules. The modified PLA film surface was characterized by optical microscopy, SERS, FT-IR, UV and TG/DTA/DSC analysis. Tensile strain of modified films was determined as well. The effect of PLA films modified with BGD on the inflammatory reactions of primary human monocyte-derived macrophages was investigated. We developed in vitro test-system by differentiating primary monocyte-derived macrophages on a coating material. Type 1 and type 2 inflammatory cytokines (TNFα, CCL18) secretion and histological biomarkers (CD206, stabilin-1) expression were analyzed by ELISA and confocal microscopy respectively. BGD-modified materials have improved thermal stability and good mechanical properties. However, BGD modifications induced additional donor-specific inflammatory reactions and suppressed tolerogenic phenotype of macrophages. Therefore, our test-system successfully demonstrated specific immunomodulatory effects of original and modified PLA-based biomaterials, and can be further applied for the examination of improved coatings for implants and identification of patient-specific reactions to implants.

  13. A single dose of dexamethasone encapsulated in polyethylene glycol-coated polylactic acid nanoparticles attenuates cisplatin-induced hearing loss following round window membrane administration.

    Science.gov (United States)

    Sun, Changling; Wang, Xueling; Zheng, Zhaozhu; Chen, Dongye; Wang, Xiaoqin; Shi, Fuxin; Yu, Dehong; Wu, Hao

    2015-01-01

    This study aimed to investigate the sustained drug release properties and hearing protection effect of polyethylene glycol-coated polylactic acid (PEG-PLA) stealth nanoparticles loaded with dexamethasone (DEX). DEX was fabricated into PEG-PLA nanoparticles using an emulsion and evaporation technique, as previously reported. The DEX-loaded PEG-PLA nanoparticles (DEX-NPs) had a hydrodynamic diameter of 130±4.78 nm, and a zeta potential of -26.13±3.28 mV. The in vitro release of DEX from DEX-NPs lasted 24 days in phosphate buffered saline (pH 7.4), 5 days in artificial perilymph (pH 7.4), and 1 day in rat plasma. Coumarin 6-labeled NPs placed onto the round window membrane (RWM) of guinea pigs penetrated RWM quickly and accumulated to the organs of Corti, stria vascularis, and spiral ganglion cells after 1 hour of administration. The DEX-NPs locally applied onto the RWM of guinea pigs by a single-dose administration continuously released DEX in 48 hours, which was significantly longer than the free DEX that was cleared out within 12 hours after administration at the same dose. Further functional studies showed that locally administrated single-dose DEX-NPs effectively preserved outer hair cells in guinea pigs after cisplatin insult and thus significantly attenuated hearing loss at 4 kHz and 8 kHz frequencies when compared to the control of free DEX formulation. Histological analyses indicated that the administration of DEX-NPs did not induce local inflammatory responses. Therefore, prolonged delivery of DEX by PEG-PLA nanoparticles through local RWM diffusion (administration) significantly protected the hair cells and auditory function in guinea pigs from cisplatin toxicity, as determined at both histological and functional levels, suggesting the potential therapeutic benefits in clinical applications.

  14. Fabrication and characterization of a foamed polylactic acid (PLA)/ thermoplastic polyurethane (TPU) shape memory polymer (SMP) blend for biomedical and clinical applications

    Science.gov (United States)

    Song, Janice J.; Srivastava, Ijya; Kowalski, Jennifer; Naguib, Hani E.

    2014-03-01

    Shape memory polymers (SMP) are a class of stimuli-responsive materials that are able to respond to external stimulus such as heat by altering their shape. Bio-compatible SMPs have a number of advantages over static materials and are being studied extensively for biomedical and clinical applications (such as tissue stents and scaffolds). A previous study has demonstrated that the bio-compatible polymer blend of polylactic acid (PLA)/ thermoplastic polyurethane (TPU) (50/50 and 70/30) exhibit good shape memory properties. In this study, the mechanical and thermo-mechanical (shape memory) properties of TPU/PLA SMP blends were characterized; the compositions studied were 80/20, 65/35, and 50/50 TPU/PLA. In addition, porous TPU/PLA SMP blends were fabricated with a gas-foaming technique; and the morphology of the porous structure of these SMPs foams were characterized with scanning electron microscopy (SEM). The TPU/PLA bio-compatible SMP blend was fabricated with melt-blending and compression molding. The glass transition temperature (Tg) of the SMP blends was determined with a differential scanning calorimeter (DSC). The mechanical properties studied were the stress-strain behavior, tensile strength, and elastic modulus; and the thermomechanical (or shape memory) properties studied were the shape fixity rate (Rf), shape recovery rate (Rr), response time, and the effect of recovery temperature on Rr. The porous 80/20 PLA/TPU SMP blend was found to have the highest tensile strength, toughness and percentage extension, as well as the lowest density and uniform pore structure in the micron and submicron scale. The porous 80/20 TPU/PLA SMP blend may be further developed for specific biomedical and clinical applications where a combination of tensile strength, toughness, and low density are required.

  15. A new growth factor controlled drug release system to promote healing of bone fractures: nanospheres of recombinant human bone morphogenetic-2 and polylactic acid.

    Science.gov (United States)

    Chen, Lin; Liu, Lei; Li, Cai; Tan, Yinghui; Zhang, Gang

    2011-04-01

    To prepare a new drug control release system, which can markedly promote the healing of bone fractures. Optimized water-in-oil-in-water multiple emulsion evaporation method, prepared nanospheres of recombinant human bone morphogenetic-2 and polylactic acid (rhBMP-2-PLA-Ns). Its physical character was determined by the enzyme linked immunosorbent assay method. Its bioactivity was measured with the microculture tetrazolium test immunohistochemical analyses, alizarin red staining and western blot analysis. rhBMP-2-PLA-Ns exhibited an even and uniform spherical appearance without adhesion, with a particle size distribution between 35 and 65 nm, and a mean size of 45 nm. The drug loading volume and encapsulation efficiency reached ([124.73 +/- 0.41] x 10(-3))% and (90.54 +/- 1.32)%, respectively. The drug release in vitro persisted for 14 days, with a mean concentration of 73.44 +/- 5.38 ng/ml, and corresponded to the Higuichi equation (r = 0.9962). The microculture tetrazolium test showed that 4 days later, the optical density value ranking was rhBMP-2-PLA-N group > rhBMP-2 group > blank control group. Fluorescence immunocytochemical analysis showed that 10 days later the fluorescent density of the rhBMP-2-PLA-N group was significantly higher than the other two groups. Western blot analysis confirmed that the amount of vascular endothelial growth factor in the rhBMP-2-PLA-N group was the greatest. This study showed that rhBMP-2-PLA-Ns have excellent biological activity, can promote proliferation, differentiation and mineralization of osteoblasts. The drug release time is suitable for fracture healing and is an ideal delivery system for fracture healing. PMID:21776677

  16. 3D-printed polylactic acid supports for enhanced ionization efficiency in desorption electrospray mass spectrometry analysis of liquid and gel samples.

    Science.gov (United States)

    Elviri, Lisa; Foresti, Ruben; Bianchera, Annalisa; Silvestri, Marco; Bettini, Ruggero

    2016-08-01

    The potential of 3D printing technology was here exploited to prepare tailored polylactic acid (PLA) supports for desorption electrospray ionization (DESI) experiments. PLA rough solid supports presenting wells of different shape (i.e. cylindrical, cubic and hemispherical cavities) were designed to accommodate samples of different physical state. The potentials of such supports in terms of sample loading capacity, sensitivity, signal stability were tested by analysing a peptide (i.e. insulin) and an aminoglycoside antibiotic (i.e. gentamicin sulphate) from solution and a chitosan-based gel. The results obtained were compared with those obtained by using a traditional polytetrafluoroethylene (PTFE) support and discussed. By using PLA support on the flat side, signal intensity improved almost twice with respect to PTFE support, whereas with spherical wells a five times improved signal sensitivity and good stability (RSD<6%) were obtained for the analysis of two model molecules. Limits of detection were in the 3-10nM range and linearity was demonstrated for both analytes in the 0.05-0.5μM range for semi-quantitative or quantitative purposes. The use of a well and the set-up of optimal source parameters allowed the analysis of samples in a gel state with good precision (RSD<10%) and accuracy (86±6-102±9%), otherwise difficult to analyse on a flat smooth surface. These findings are of great interest and stimulus to exploit the advantages of 3D printing technology for the development of devices for a DESI source, presenting different shapes or configuration as a function of the sample types. PMID:27216689

  17. Antimicrobial polylactic acid packaging films against Listeria and Salmonella in culture medium and on ready-to-eat meat

    Science.gov (United States)

    The contamination of Listeria monocytogenes and Salmonella spp. in ready-to-eat (RTE) meat products has been a concern for the meat industry. In this study, edible chitosan-acid solutions incorporating lauric arginate ester (LAE), sodium lactate (NaL) and sorbic acid (SA) alone or in combinations we...

  18. Preparation of flame retardant basalt fiber fabric/polylactic acid composite%阻燃型玄武岩织物/聚乳酸复合材料的研制

    Institute of Scientific and Technical Information of China (English)

    吕丽华; 刘桂彬; 孙艳丽

    2013-01-01

    The hot pressing molding process was used to prepare flame retardant basalt fiber fabric/ polylactic acid composite, and the influences of the mass fraction of polylactic acid, hot pressing pressure and temperature, and flame retardant agent mass fraction on the tensile strength, bending strength and limiting oxygen index of the composite were examined. Through orthogonal experiments, range analysis and single factor analysis, the optimal process conditions for making the composite were obtained as follows; mass fraction of flame retardant agent 30% , mass fraction of polylactic acid 64.6% , hot pressing pressure 5 MPa, and hot pressing temperature 185 t. The results showed that although the mechanical properties of the basalt fiber fabric/polylactic acid composite prepared with addition of flame retardant agent magnesium hydrate reduced slightly, they were still better comparatively, and its limiting oxygen index could be increased up to 35. 2% .%采用热压法成型工艺制备阻燃型玄武岩织物增强聚乳酸复合材料,考察聚乳酸质量分数、热压压力、热压温度、阻燃剂质量分数对复合材料拉伸强度、弯曲强度及极限氧指数的影响.通过正交试验、极差分析及单因素分析,得出制备阻燃型玄武岩织物增强聚乳酸复合材料的优化工艺:阻燃剂质量分数为30%,聚乳酸质量分数为64.6%,热压压力为5 MPa,热压温度为185℃.结果表明:添加氢氧化镁阻燃剂制备的阻燃型玄武岩织物增强聚乳酸复合材料,其力学性能略有降低,但仍比较优异,且极限氧指数可达到35.2%.

  19. Synthesis, Properties and Applications of Biodegradable Polymers Derived from Diols and Dicarboxylic Acids: From Polyesters to Poly(ester amides

    Directory of Open Access Journals (Sweden)

    Angélica Díaz

    2014-04-01

    Full Text Available Poly(alkylene dicarboxylates constitute a family of biodegradable polymers with increasing interest for both commodity and speciality applications. Most of these polymers can be prepared from biobased diols and dicarboxylic acids such as 1,4-butanediol, succinic acid and carbohydrates. This review provides a current status report concerning synthesis, biodegradation and applications of a series of polymers that cover a wide range of properties, namely, materials from elastomeric to rigid characteristics that are suitable for applications such as hydrogels, soft tissue engineering, drug delivery systems and liquid crystals. Finally, the incorporation of aromatic units and α-amino acids is considered since stiffness of molecular chains and intermolecular interactions can be drastically changed. In fact, poly(ester amides derived from naturally occurring amino acids offer great possibilities as biodegradable materials for biomedical applications which are also extensively discussed.

  20. 聚乳酸纤维与棉纤维不同混纺比对纱线力学性能的影响%Different Blended Ratio Effected on Yarn Mechanical Properties of the Yarn Blended with Corn Polylactic Acid Fiber and Cotton

    Institute of Scientific and Technical Information of China (English)

    赵凯; 潘福奎; 王春

    2012-01-01

    文章对聚乳酸纤维的性能和发展应用进行了阐述。通过设定实验条件,对聚乳酸纤维和棉纤维不同混纺比下的拉伸性能进行测试、分析,并得出结论。%The properties and application of polylactic acid fiber were elaboreted. The mechanical properties of corn polylactic acid fiber and cotton fiber were tested and analysed, according to setted experimental conditions, and the conclusions drawn.