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Sample records for biodegradable polyterephthalate-co-phosphates synthesis

  1. Nitroaromatic Compounds, from Synthesis to Biodegradation

    PubMed Central

    Ju, Kou-San; Parales, Rebecca E.

    2010-01-01

    Summary: Nitroaromatic compounds are relatively rare in nature and have been introduced into the environment mainly by human activities. This important class of industrial chemicals is widely used in the synthesis of many diverse products, including dyes, polymers, pesticides, and explosives. Unfortunately, their extensive use has led to environmental contamination of soil and groundwater. The nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalcitrance of these compounds to biodegradation. The electron-withdrawing nature of the nitro group, in concert with the stability of the benzene ring, makes nitroaromatic compounds resistant to oxidative degradation. Recalcitrance is further compounded by their acute toxicity, mutagenicity, and easy reduction into carcinogenic aromatic amines. Nitroaromatic compounds are hazardous to human health and are registered on the U.S. Environmental Protection Agency's list of priority pollutants for environmental remediation. Although the majority of these compounds are synthetic in nature, microorganisms in contaminated environments have rapidly adapted to their presence by evolving new biodegradation pathways that take advantage of them as sources of carbon, nitrogen, and energy. This review provides an overview of the synthesis of both man-made and biogenic nitroaromatic compounds, the bacteria that have been identified to grow on and completely mineralize nitroaromatic compounds, and the pathways that are present in these strains. The possible evolutionary origins of the newly evolved pathways are also discussed. PMID:20508249

  2. Synthesis of biodegradable polymers using biocatalysis with Yarrowia lipolytica lipase.

    PubMed

    Barrera-Rivera, Karla A; Flores-Carreón, Arturo; Martínez-Richa, Antonio

    2012-01-01

    Yarrowia lipolytica lipase (YLL) was used as catalyst in the enzymatic ring-opening polymerization (ROP) of ε-caprolactone. This low-cost solid-state lipase produces low-molecular-weight polyesters with unique multiphase morphology as determined by carbon-13 NMR. YLL attaches sugar head groups to polycaprolactone in a one-pot biocatalytic pathway. Synthesis of α-ω-telechelic (polymer with two reactive hydroxyl end groups) PCL diols is achieved by enzymatic ROP with YLL immobilized on the macroporous resin Lewatit VPOC 1026, and in the presence of diethylene glycol or poly(ethylene glycol). Biodegradable linear polyester urethanes are prepared by polycondensation between synthesized PCL diols and hexamethylene-diisocyanate. PMID:22426736

  3. Green synthesis of Au nanostructures at room temperature using biodegradable plant surfactants

    EPA Science Inventory

    One-step green synthesis of gold (Au) nanostructures is described using naturally occurring biodegradable plant surfactants such as VeruSOL-3™ (mixture of d-limonene and plant-based surfactants), VeruSOL-10™, VeruSOL-11™ and VeruSOL-12™ (individual plant-based surfactants deri...

  4. MICROWAVE-ASSISTED SYNTHESIS OF NOBLE NANOSTRUCTURES USING BIODEGRADABLE POLYMER CARBOXYMETHYL CELLULOSE

    EPA Science Inventory

    Microwave-assisted (MW) synthesis of noble metals such as Au, Pt and Pd is reported using biodegradable polymer carboxymethyl cellulose (CMC) at 100°C within few seconds. The possible reduction entails the coupling of polar hydroxyl units in beta-glucopyranose units with micr...

  5. MICROWAVE-ASSISTED SYNTHESIS OF NOBLE NANOSTRUCTURES USING BIODEGRADABLE POLYMER CARBOXYMETHYL CELLULOSE

    EPA Science Inventory

    Microwave-assisted synthesis of noble nanostructures (Au, Pt, and Pd) using biodegradable polymer carboxymethyl cellulose (CMC) under microwave irradiation (MW) at 100 0C is reported. The reaction occurs within a few minutes, whereas at room temperature the reaction does not pro...

  6. Synthesis, Biodegradability, and Biocompatibility of Lysine Diisocyanate–Glucose Polymers

    PubMed Central

    ZHANG, JIAN-YING; BECKMAN, ERIC J.; HU, JING; YANG, GUO-GUANG; AGARWAL, SUDHA; HOLLINGER, JEFFREY O.

    2016-01-01

    The success of a tissue-engineering application depends on the use of suitable biomaterials that degrade in a timely manner and induce the least immunogenicity in the host. With this purpose in mind, we have attempted to synthesize a novel nontoxic biodegradable lysine diisocyanate (LDI)-and glucose-based polymer via polymerization of highly purified LDI with glucose and its subsequent hydration to form a spongy matrix. The LDI–glucose polymer was degradable in aqueous solutions at 37, 22, and 4°C, and yielded lysine and glucose as breakdown products. The degradation products of the LDI–glucose polymer did not significantly affect the pH of the solution. The physical properties of the polymer were found to be adequate for supporting cell growth in vitro, as evidenced by the fact that rabbit bone marrow stromal cells (BMSCs) attached to the polymer matrix, remained viable on its surface, and formed multilayered confluent cultures with retention of their phenotype over a period of 2 to 4 weeks. These observations suggest that the LDI–glucose polymer and its degradation products were nontoxic in vitro. Further examination in vivo over 8 weeks revealed that subcutaneous implantation of hydrated matrix degraded in vivo three times faster than in vitro. The implanted polymer was not immunogenic and did not induce antibody responses in the host. Histological analysis of the implanted polymer showed that LDI–glucose polymer induced a minimal foreign body reaction, with formation of a capsule around the degrading polymer. The results suggest that biodegradable peptide-based polymers can be synthesized, and may potentially find their way into biomedical applications because of their biodegradability and biocompatibility. PMID:12459056

  7. Synthesis and characterization of biomimetic citrate-based biodegradable composites.

    PubMed

    Tran, Richard T; Wang, Liang; Zhang, Chang; Huang, Minjun; Tang, Wanjin; Zhang, Chi; Zhang, Zhongmin; Jin, Dadi; Banik, Brittany; Brown, Justin L; Xie, Zhiwei; Bai, Xiaochun; Yang, Jian

    2014-08-01

    Natural bone apatite crystals, which mediate the development and regulate the load-bearing function of bone, have recently been associated with strongly bound citrate molecules. However, such understanding has not been translated into bone biomaterial design and osteoblast cell culture. In this work, we have developed a new class of biodegradable, mechanically strong, and biocompatible citrate-based polymer blends (CBPBs), which offer enhanced hydroxyapatite binding to produce more biomimetic composites (CBPBHAs) for orthopedic applications. CBPBHAs consist of the newly developed osteoconductive citrate-presenting biodegradable polymers, crosslinked urethane-doped polyester and poly (octanediol citrate), which can be composited with up to 65 wt % hydroxyapatite. CBPBHA networks produced materials with a compressive strength of 116.23 ± 5.37 MPa comparable to human cortical bone (100-230 MPa), and increased C2C12 osterix gene and alkaline phosphatase gene expression in vitro. The promising results above prompted an investigation on the role of citrate supplementation in culture medium for osteoblast culture, which showed that exogenous citrate supplemented into media accelerated the in vitro phenotype progression of MG-63 osteoblasts. After 6 weeks of implantation in a rabbit lateral femoral condyle defect model, CBPBHA composites elicited minimal fibrous tissue encapsulation and were well integrated with the surrounding bone tissues. The development of citrate-presenting CBPBHA biomaterials and preliminary studies revealing the effects of free exogenous citrate on osteoblast culture shows the potential of citrate biomaterials to bridge the gap in orthopedic biomaterial design and osteoblast cell culture in that the role of citrate molecules has previously been overlooked. PMID:23996976

  8. Synthesis and Characterization of Biomimetic Citrate-Based Biodegradable Composites

    PubMed Central

    Tran, Richard T.; Wang, Liang; Zhang, Chang; Huang, Minjun; Tang, Wanjin; Zhang, Chi; Zhang, Zhongmin; Jin, Dadi; Banik, Brittany; Brown, Justin L.; Xie, Zhiwei; Bai, Xiaochun; Yang, Jian

    2013-01-01

    Natural bone apatite crystals, which mediate the development and regulate the load-bearing function of bone, have recently been associated with strongly bound citrate molecules. However, such understanding has not been translated into bone biomaterial design and osteoblast cell culture. In this work, we have developed a new class of biodegradable, mechanically strong, and biocompatible citrate-based polymer blends (CBPBs), which offer enhanced hydroxyapatite binding to produce more biomimetic composites (CBPBHAs) for orthopedic applications. CBPBHAs consist of the newly developed osteoconductive citrate-presenting biodegradable polymers, crosslinked urethane-doped polyester (CUPE) and poly (octanediol citrate) (POC), which can be composited with up to 65 wt.-% hydroxyapatite (HA). CBPBHA networks produced materials with a compressive strength of 116.23 ± 5.37 MPa comparable to human cortical bone (100 – 230 MPa), and increased C2C12 osterix (OSX) gene and alkaline phosphatase (ALP) gene expression in vitro. The promising results above prompted an investigation on the role of citrate supplementation in culture medium for osteoblast culture, which showed that exogenous citrate supplemented into media accelerated the in vitro phenotype progression of MG-63 osteoblasts. After 6-weeks of implantation in a rabbit lateral femoral condyle defect model, CBPBHA composites elicited minimal fibrous tissue encapsulation and were well integrated with the surrounding bone tissues. The development of citrate-presenting CBPBHA biomaterials and preliminary studies revealing the effects of free exogenous citrate on osteoblast culture shows the potential of citrate biomaterials to bridge the gap in orthopedic biomaterial design and osteoblast cell culture in that the role of citrate molecules has previously been overlooked. PMID:23996976

  9. Synthesis and Characterization of Biodegradable Polyurethane for Hypopharyngeal Tissue Engineering

    PubMed Central

    Shen, Zhisen; Lu, Dakai; Li, Qun; Zhang, Zongyong

    2015-01-01

    Biodegradable crosslinked polyurethane (cPU) was synthesized using polyethylene glycol (PEG), L-lactide (L-LA), and hexamethylene diisocyanate (HDI), with iron acetylacetonate (Fe(acac)3) as the catalyst and PEG as the extender. Chemical components of the obtained polymers were characterized by FTIR spectroscopy, 1H NMR spectra, and Gel Permeation Chromatography (GPC). The thermodynamic properties, mechanical behaviors, surface hydrophilicity, degradability, and cytotoxicity were tested via differential scanning calorimetry (DSC), tensile tests, contact angle measurements, and cell culture. The results show that the synthesized cPU possessed good flexibility with quite low glass transition temperature (Tg, −22°C) and good wettability. Water uptake measured as high as 229.7 ± 18.7%. These properties make cPU a good candidate material for engineering soft tissues such as the hypopharynx. In vitro and in vivo tests showed that cPU has the ability to support the growth of human hypopharyngeal fibroblasts and angiogenesis was observed around cPU after it was implanted subcutaneously in SD rats. PMID:25839041

  10. Synthesis and characterization of biodegradable polyurethane for hypopharyngeal tissue engineering.

    PubMed

    Shen, Zhisen; Lu, Dakai; Li, Qun; Zhang, Zongyong; Zhu, Yabin

    2015-01-01

    Biodegradable crosslinked polyurethane (cPU) was synthesized using polyethylene glycol (PEG), L-lactide (L-LA), and hexamethylene diisocyanate (HDI), with iron acetylacetonate (Fe(acac)3) as the catalyst and PEG as the extender. Chemical components of the obtained polymers were characterized by FTIR spectroscopy, (1)H NMR spectra, and Gel Permeation Chromatography (GPC). The thermodynamic properties, mechanical behaviors, surface hydrophilicity, degradability, and cytotoxicity were tested via differential scanning calorimetry (DSC), tensile tests, contact angle measurements, and cell culture. The results show that the synthesized cPU possessed good flexibility with quite low glass transition temperature (T g , -22°C) and good wettability. Water uptake measured as high as 229.7 ± 18.7%. These properties make cPU a good candidate material for engineering soft tissues such as the hypopharynx. In vitro and in vivo tests showed that cPU has the ability to support the growth of human hypopharyngeal fibroblasts and angiogenesis was observed around cPU after it was implanted subcutaneously in SD rats. PMID:25839041

  11. Biodegradable injectable polyurethanes: synthesis and evaluation for orthopaedic applications.

    PubMed

    Adhikari, Raju; Gunatillake, Pathiraja A; Griffiths, Ian; Tatai, Lisa; Wickramaratna, Malsha; Houshyar, Shadi; Moore, Tim; Mayadunne, Roshan T M; Field, John; McGee, Margaret; Carbone, Tania

    2008-10-01

    Biodegradable polyurethanes offer advantages in the design of injectable or preformed scaffolds for tissue engineering and other medical implant applications. We have developed two-part injectable prepolymer systems (prepolymer A and B) consisting of lactic acid and glycolic acid based polyester star polyols, pentaerythritol (PE) and ethyl lysine diisocyanate (ELDI). This study reports on the formulation and properties of a series of cross linked polyurethanes specifically developed for orthopaedic applications. Prepolymer A was based on PE and ELDI. Polyester polyols (prepolymer B) were based on PE and dl-lactic acid (PEDLLA) or PE and glycolic acid (PEGA) with molecular weights 456 and 453, respectively. Several cross linked porous and non-porous polyurethanes were prepared by mixing and curing prepolymers A and B and their mechanical and thermal properties, in vitro (PBS/37 degrees C/pH 7.4) and in vivo (sheep bi-lateral) degradation evaluated. The effect of incorporating beta-tricalcium phosphate (beta-TCP, 5 microns, 10 wt.%) was also investigated. The cured polymers exhibited high compressive strength (100-190 MPa) and modulus (1600-2300 MPa). beta-TCP improved mechanical properties in PEDLLA based polyurethanes and retarded the onset of in vitro and in vivo degradation. Sheep study results demonstrated that the polymers in both injectable and precured forms did not cause any surgical difficulties or any adverse tissue response. Evidence of new bone growth and the gradual degradation of the polymers were observed with increased implant time up to 6 months. PMID:18632149

  12. Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

    NASA Astrophysics Data System (ADS)

    Aras, Neny Rasnyanti M.; Arcana, I. Made

    2015-09-01

    An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm-1 which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese stearate

  13. Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

    SciTech Connect

    Aras, Neny Rasnyanti M. Arcana, I Made

    2015-09-30

    An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm{sup −1} which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese

  14. Deep eutectic solvent-assisted synthesis of biodegradable polyesters with antibacterial properties.

    PubMed

    García-Argüelles, Sara; Serrano, M Concepción; Gutiérrez, María C; Ferrer, M Luisa; Yuste, Luis; Rojo, Fernando; del Monte, Francisco

    2013-07-30

    Bacterial infection related to the implantation of medical devices represents a serious clinical complication, with dramatic consequences for many patients. In past decades, numerous attempts have been made to develop materials with antibacterial and/or antifouling properties by the incorporation of antibiotic and/or antiseptic compounds. In this context, deep eutectic solvents (DESs) are acquiring increasing interest not only as efficient carriers of active principle ingredients (APIs) but also as assistant platforms for the synthesis of a wide repertoire of polymer-related materials. Herein, we have successfully prepared biodegradable poly(octanediol-co-citrate) polyesters with acquired antibacterial properties by the DES-assisted incorporation of quaternary ammonium or phosphonium salts into the polymer network. In the resulting polymers, the presence of these salts (i.e., choline chloride, tetraethylammonium bromide, hexadecyltrimethylammonium bromide, and methyltriphenylphosphonium bromide) inhibits bacterial growth in the early postimplantation steps, as tested in cultures of Escherichia coli on solid agar plates. Later, positive polymer cytocompatibility is expected to support cell colonization, as anticipated from in vitro preliminary studies with L929 fibroblasts. Finally, the attractive elastic properties of these polyesters permit matching those of soft tissues such as skin. For all of these reasons, we envisage the utility of some of these antibacterial, biocompatible, and biodegradable polyesters as potential candidates for the preparation of antimicrobial wound dressings. These results further emphasize the enormous versatility of DES-assisted synthesis for the incorporation, in the synthesis step, of a wide palette of APIs into polymeric networks suitable for biomedical applications. PMID:23808373

  15. Synthesis and Characterization of Biodegradable Lignin Nanoparticles with Tunable Surface Properties.

    PubMed

    Richter, Alexander P; Bharti, Bhuvnesh; Armstrong, Hinton B; Brown, Joseph S; Plemmons, Dayne; Paunov, Vesselin N; Stoyanov, Simeon D; Velev, Orlin D

    2016-06-28

    Lignin nanoparticles can serve as biodegradable carriers of biocidal actives with minimal environmental footprint. Here we describe the colloidal synthesis and interfacial design of nanoparticles with tunable surface properties using two different lignin precursors, Kraft (Indulin AT) lignin and Organosolv (high-purity lignin). The green synthesis process is based on flash precipitation of dissolved lignin polymer, which enabled the formation of nanoparticles in the size range of 45-250 nm. The size evolution of the two types of lignin particles is fitted on the basis of modified diffusive growth kinetics and mass balance dependencies. The surface properties of the nanoparticles are fine-tuned by coating them with a cationic polyelectrolyte, poly(diallyldimethylammonium chloride). We analyze how the colloidal stability and dispersion properties of these two types of nanoparticles vary as a function of pH and salinities. The data show that the properties of the nanoparticles are governed by the type of lignin used and the presence of polyelectrolyte surface coating. The coating allows the control of the nanoparticles' surface charge and the extension of their stability into strongly basic regimes, facilitating their potential application at extreme pH conditions. PMID:27268077

  16. Use of alginate, chitosan and cellulose nanocrystals as emulsion stabilizers in the synthesis of biodegradable polymeric nanoparticles.

    PubMed

    Rescignano, Nicoletta; Fortunati, Elena; Armentano, Ilaria; Hernandez, Rebeca; Mijangos, Carmen; Pasquino, Rossana; Kenny, José Maria

    2015-05-01

    Biopolymeric nanoparticles (NPs) based on a biodegradable poly(DL-Lactide-co-Glycolide) PLGA copolymer matrix combined with alginate, chitosan and nanostructured cellulose crystals as three different natural emulsion stabilizers, were synthesized by a double emulsion (water/oil/water) method with subsequent solvent evaporation. The morphological, thermal, chemical and rheological properties of the novel designed NPs and the effect of the different emulsion stabilizers used during the synthesis were deeply investigated in order to optimize the synthesis procedure and the development of biodegradable nanoparticles coated with natural polymers. The morphological analysis of the produced nanoparticles showed that all the different formulations presented a spherical shape with smooth surface. Infrared spectroscopy investigations showed that the PLGA copolymer maintained its backbone structure and confirmed the presence of chitosan, alginate and cellulose nanocrystals (CNC) on the nanoparticle surface. The obtained results suggest that PLGA nanoparticles with CNC as emulsion stabilizer might represent promising formulations opening new perspective in the field of self-assembly of biodegradable nanomaterials for medical and pharmaceutical applications. PMID:25596366

  17. Synthesis of Biodegradable Polymer Micro- and Nanoparticles for Controlled Drug Delivery by Multiplexed Electrosprays

    NASA Astrophysics Data System (ADS)

    Almeria, Begona

    The goal of controlled drug delivery is to administer sustained amounts of a therapeutic agent over a prolonged period of time, improving the drug efficacy as compared to conventional, bolus doses that lead to variable concentrations of drug in blood. Although there are several systems capable to provide such a continuous-dose-based treatment, the use of biodegradable polymer micro- and, especially, nanoparticles offers multiple advantages with respect to other platforms. Their small size allows them to pass through physical barriers in the body and reach the site of treatment, allowing for a localized delivery, reducing side effects and toxicity. Polymer nanoparticles have lower clearance by the immune system, and are especially useful in intracellular delivery, delivery to the lymphatic system and the treatment of tumors, where the site of treatment is difficult to reach by larger particles. Conventional methods for biodegradable particle production rely predominately on batch, emulsion preparation methods and suffer from several shortcomings: low encapsulation efficiency (˜10% for hydrophilic drugs), difficulty to generate sufficiently small (d<100nm) particles, poor control over particle size distribution, broad size distributions at the micro scale, and poor repeatability. We have developed an alternative process based on electrospray (ES) that offers distinct advantages and overcomes all of these limitations. We demonstrate this process with the Poly(DL-lactic-co-glycolic acid) (PLGA) system encapsulating agents such as Doxorubicin, Rhodamine B and Rhodamine B octadecyl ester prechlorate. We also employ this method for the generation of theranostic systems that combine their therapeutic mission with imaging capabilities to detect the biodistribution of particles inside the body. PLGA microparticles in different sizes, morphologies and compactness are generated using the electrospray-drying route. The size of the synthesized particles is primarily controlled

  18. Gemini Alkyldeoxy-D-Glucitolammonium Salts as Modern Surfactants and Microbiocides: Synthesis, Antimicrobial and Surface Activity, Biodegradation

    PubMed Central

    Brycki, Bogumił; Szulc, Adrianna

    2014-01-01

    Dimeric quaternary alkylammonium salts possess a favourable surface and antimicrobial activity. In this paper we describe synthesis, spectroscopic analysis, surface and antimicrobial activity as well as biodegradability of polymethylene-α,ω-bis(N,N-dialkyl-N-deoxy-D-glucitolammonium iodides), a new group of dimeric quaternary ammonium salts. This new group of gemini surfactants can be produced from chemicals which come from renewable sources. The structure of products has been determined by the FTIR and 1H and 13C NMR spectroscopy. The biodegradability, surface activity and antimicrobial efficacy against Escherichia coli, Staphylococcus aureus, Candida albicans, Aspergillus niger and Penicillium chrysogenum were determined. The influence of the number of alkyl chains and their lengths on surface and antimicrobial properties has been shown. In general, dimeric quaternary alkyldeoxy-D-glucitolammonium salts with long alkyl substituents show favourable surface properties and an excellent antimicrobial activity. PMID:24416314

  19. Biodegradable Polydepsipeptides

    PubMed Central

    Feng, Yakai; Guo, Jintang

    2009-01-01

    This paper reviews the synthesis, characterization, biodegradation and usage of bioresorbable polymers based on polydepsipeptides. The ring-opening polymerization of morpholine-2,5-dione derivatives using organic Sn and enzyme lipase is discussed. The dependence of the macroscopic properties of the block copolymers on their structure is also presented. Bioresorbable polymers based on polydepsipeptides could be used as biomaterials in drug controlled release, tissue engineering scaffolding and shape-memory materials. PMID:19333423

  20. Synthesis and toxicity evaluation of hydrophobic ionic liquids for volatile organic compounds biodegradation in a two-phase partitioning bioreactor.

    PubMed

    Rodriguez Castillo, Alfredo Santiago; Guihéneuf, Solène; Le Guével, Rémy; Biard, Pierre-François; Paquin, Ludovic; Amrane, Abdeltif; Couvert, Annabelle

    2016-04-15

    Synthesis of several hydrophobic ionic liquids (ILs), which might be selected as good candidates for degradation of hydrophobic volatile organic compounds in a two-phase partitioning bioreactor (TPPB), were carried out. Several bioassays were also realized, such as toxicity evaluation on activated sludge and zebrafish, cytotoxicity, fluoride release in aqueous phase and biodegradability in order to verify their possible effects in case of discharge in the aquatic environment and/or human contact during industrial manipulation. The synthesized compounds consist of alkylimidazoliums, functionalized imidazoliums, isoqinoliniums, triazoliums, sulfoniums, pyrrolidiniums and morpholiniums and various counter-ions such as: PF6(-), NTf2(-) and NfO(-). Toxicity evaluation on activated sludge of each compound (5% v/v of IL) was assessed by using a glucose uptake inhibition test. Toxicity against zebrafish and cytotoxicity were evaluated by the ImPACCell platform of Rennes (France). Fluoride release in water was estimated by regular measurements using ion chromatography equipment. IL biodegradability was determined by measuring BOD28 of aqueous samples (compound concentration,1mM). All ILs tested were not biodegradable; while some of them were toxic toward activated sludge. Isoquinolinium ILs were toxic to human cancerous cell lines. Nevertheless no toxicity was found against zebrafish Danio rerio. Only one IL released fluoride after long-time agitation. PMID:26785216

  1. SYNTHESIS OF THERMALLY STABLE CARBOXYMETHYL CELLULOSE/METAL BIODEGRADABLE NANOCOMPOSITES FOR POTENTIAL BIOLOGICAL APPLICATIONS

    EPA Science Inventory

    A green approach is described that generates bulk quantities of nanocomposites containing transition metals such as Cu, Ag, In and Fe at room temperature using a biodegradable polymer carboxymethyl cellulose (CMC) by reacting respective metal salts with sodium salt of CMC in aqu...

  2. Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

    NASA Astrophysics Data System (ADS)

    Asriza, Ristika O.; Arcana, I. Made

    2015-09-01

    Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm-1 indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

  3. Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

    SciTech Connect

    Asriza, Ristika O.; Arcana, I Made

    2015-09-30

    Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm{sup −1} indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

  4. Synthesis and flocculation properties of gum ghatti and poly(acrylamide-co-acrylonitrile) based biodegradable hydrogels.

    PubMed

    Mittal, Hemant; Jindal, Rajeev; Kaith, Balbir Singh; Maity, Arjun; Ray, Suprakas Sinha

    2014-12-19

    This article reports the development of biodegradable flocculants based on graft co-polymers of gum ghatti (Gg) and a mixture of acrylamide and acrylonitrile co-monomers (AAm-co-AN). The hydrogel polymer exhibited an excellent swelling capacity of 921% in neutral medium at 60°C. The polymer was used to remove saline water from various petroleum fraction-saline water emulsions. The flocculation characteristics of the hydrogel polymer were studied in turbid kaolin solution as a function of the amount of polymer and the solution temperature and pH. Biodegradation studies of hydrogel polymer were conducted using the soil composting method, and the degradation process was constantly monitored using scanning electron microscopy and Fourier transform infrared spectroscopy techniques. The results demonstrated an 89.47% degradation of the polymer after 60 days. Finally, the hydrogel polymer adsorbed 98% of cationic dyes from the aqueous solutions. PMID:25263897

  5. A facile synthesis of lipid stabilized gold nanoparticles: a step towards biodegradable biosensors.

    PubMed

    Abraham, Sinoj; Narine, Suresh S

    2011-08-01

    A new class of polylactone was successfully synthesized and utilized for the encapsulation and stabilization of gold nanoparticles. Core/shell nanoparticle architecture, in which a layer of this polymer surrounds the nanoparticle core have been investigated both as a means to improve the stability and surface chemistry and as a way of accessing unique physical properties that are not possible from one nano-material alone. Given the fact that only few systems has so far been developed for the encapsulation of nanoparticles, our success in using a new biodegradable biopolymer with inbuilt functionality reveals the robustness of this work. The biodegradability of this polylactone was evaluated using scanning electron microscopy (SEM). The morphology and stability of these gold-polymer hybrids were evaluated by using the transmission electron microscopy (TEM) and UV-VIS spectroscopy. PMID:22103117

  6. Synthesis and biodegradation of the VX nerve agent derivative 2-DIISO-propylaminoethylsulfonic acid

    SciTech Connect

    Warner, C.H.; Labare, M.P.; Wessel, T.E.

    1996-10-01

    The United States is currently examining biodegradation methods to demilitarize chemical weapons. The nerve agent, O-ethyl-S-(2-diisopropylamino-ethyl)methylphosphonothiolate (VX) is first chemically inactivated with water at 90% yielding two fragments. One fragment is 2-diisopropylaminoethanethiol which quickly reacts with another thiol fragment forming the disulfide, bis(2-diisopropylaminoethyl)disulfide. The presence of the disulfide bond in this compound renders it resistant to biodegradation. Methods for converting the disulfide to the sulfonic acid are currently being pursued by treatment with performic acid. However, the sulfonic: acid has been synthesized by an independent method. Preliminary experiments indicate that the sulfonic acid at 1.0 and 0.5 mM is degraded by Rhodococcus dp. strain IGTS8 as evidenced by an increase in the optical density at 600 nm.

  7. Synthesis, mechanical properties, biocompatibility, and biodegradation of polyurethane networks from lysine polyisocyanates.

    PubMed

    Guelcher, Scott A; Srinivasan, Abiraman; Dumas, Jerald E; Didier, Jonathan E; McBride, Sean; Hollinger, Jeffrey O

    2008-04-01

    Bone defects, such as compressive fractures in the vertebral bodies, are frequently treated with acrylic bone cements (e.g., PMMA). Although these biomaterials have sufficient mechanical properties for fixing the fracture, they are non-degradable and do not remodel or integrate with host tissue. In an alternative approach, biodegradable polyurethane (PUR) networks have been synthesized that are designed to integrate with host tissue and degrade to non-cytotoxic decomposition products. PUR networks have been prepared by two-component reactive liquid molding of low-viscosity quasi-prepolymers derived from lysine polyisocyanates and poly(epsilon-caprolactone-co-DL-lactide-co-glycolide) triols. The composition, thermal transitions, and mechanical properties of the biomaterials were measured. The values of Young's modulus ranged from 1.20-1.43 GPa, and the compressive yield strength varied from 82 to 111 MPa, which is comparable to the strength of PMMA bone cements. In vitro, the materials underwent controlled biodegradation to non-cytotoxic decomposition products, and supported the attachment and proliferation of MC3T3 cells. When cultured in osteogenic medium on the PUR networks, MC3T3 cells deposited mineralized extracellular matrix, as evidenced by von Kossa staining and tetracycline labeling. Considering the favorable mechanical and biological properties, as well as the low-viscosity of the reactive intermediates used to prepare the PUR networks, these biomaterials are potentially useful as injectable, biodegradable bone cements for fracture healing. PMID:18255140

  8. Synthesis, Properties and Applications of Biodegradable Polymers Derived from Diols and Dicarboxylic Acids: From Polyesters to Poly(ester amide)s

    PubMed Central

    Díaz, Angélica; Katsarava, Ramaz; Puiggalí, Jordi

    2014-01-01

    Poly(alkylene dicarboxylate)s 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 amide)s derived from naturally occurring amino acids offer great possibilities as biodegradable materials for biomedical applications which are also extensively discussed. PMID:24776758

  9. Synthesis and characterization of conductive, biodegradable, elastomeric polyurethanes for biomedical applications.

    PubMed

    Xu, Cancan; Yepez, Gerardo; Wei, Zi; Liu, Fuqiang; Bugarin, Alejandro; Hong, Yi

    2016-09-01

    Biodegradable conductive polymers are currently of significant interest in tissue repair and regeneration, drug delivery, and bioelectronics. However, biodegradable materials exhibiting both conductive and elastic properties have rarely been reported to date. To that end, an electrically conductive polyurethane (CPU) was synthesized from polycaprolactone diol, hexadiisocyanate, and aniline trimer and subsequently doped with (1S)-(+)-10-camphorsulfonic acid (CSA). All CPU films showed good elasticity within a 30% strain range. The electrical conductivity of the CPU films, as enhanced with increasing amounts of CSA, ranged from 2.7 ± 0.9 × 10(-10) to 4.4 ± 0.6 × 10(-7) S/cm in a dry state and 4.2 ± 0.5 × 10(-8) to 7.3 ± 1.5 × 10(-5) S/cm in a wet state. The redox peaks of a CPU1.5 film (molar ratio CSA:aniline trimer = 1.5:1) in the cyclic voltammogram confirmed the desired good electroactivity. The doped CPU film exhibited good electrical stability (87% of initial conductivity after 150 hours charge) as measured in a cell culture medium. The degradation rates of CPU films increased with increasing CSA content in both phosphate-buffered solution (PBS) and lipase/PBS solutions. After 7 days of enzymatic degradation, the conductivity of all CSA-doped CPU films had decreased to that of the undoped CPU film. Mouse 3T3 fibroblasts proliferated and spread on all CPU films. This developed biodegradable CPU with good elasticity, electrical stability, and biocompatibility may find potential applications in tissue engineering, smart drug release, and electronics. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2305-2314, 2016. PMID:27124702

  10. Synthesis and characterization of highly-magnetic biodegradable poly(d,l-lactide-co-glycolide) nanospheres.

    PubMed

    Liu, Xianqiao; Kaminski, Michael D; Chen, Haitao; Torno, Michael; Taylor, LaToyia; Rosengart, Axel J

    2007-05-14

    The objective of this study was to develop high magnetization, biodegradable/biocompatible polymer-coated magnetic nanospheres for biomedical applications. Magnetic spheres were prepared by a modified single oil-in-water emulsion-solvent evaporation method utilizing highly-concentrated hydrophobic magnetite and poly(d,l lactide-co-glycolide) (PLGA). Hydrophobic magnetite prepared using oleic acid exhibited high magnetite concentrations (84 wt.%) and good miscibility with biopolymer solvents to form a stable oily suspension. The oily suspension was then emulsified within an aqueous solution containing poly(vinyl alcohol). After rapid evaporation of the organic solvent, we obtained solid magnetic nanospheres. We characterized these spheres in terms of external morphology, microstructure, size and zeta potential, magnetite content and distribution within the nanospheres, and magnetic properties. The results showed good encapsulation where the magnetite distorted the smooth surface morphology only at the highest magnetite concentrations. The mean diameter was 360-370 nm with polydispersity indices of 0.12-0.20. We obtained high magnetite content (40-60%) and high magnetization (26-40 emu/g). The high magnetization properties were obtained while leaving sufficient polymer to retain drugs making these biodegradable spheres suitable as a potential platform for the design of magnetically-guided drug delivery and other in vivo biomagnetic applications. PMID:17350131

  11. Synthesis and biocompatibility of a biodegradable and functionalizable thermo-sensitive hydrogel

    PubMed Central

    Sinha, Mantosh K.; Gao, Jin; Stowell, Chelsea E. T.; Wang, Yadong

    2015-01-01

    Injectable thermal gels are a useful tool for drug delivery and tissue engineering. However, most thermal gels do not solidify rapidly at body temperature (37°C). We addressed this by synthesizing a thermo-sensitive, rapidly biodegrading hydrogel. Our hydrogel, poly(ethylene glycol)-co-poly(propanol serinate hexamethylene urethane) (EPSHU), is an ABA block copolymer comprising A, methoxy poly ethylene glycol group and B, poly (propanol L-serinate hexamethylene urethane). EPSHU was characterized by gel permeation chromatography for molecular weight and 1H NMR and Fourier transformed infrared for structure. Rheological studies measured the phase transition temperature. In vitro degradation in cholesterol esterase and in Dulbecco's phosphate buffered saline (DPBS) was tracked using the average molecular weight measured by gel permeation chromatography. LIVE/DEAD and resazurin reduction assays performed on NIH 3T3 fibroblasts exposed to EPSHU extracts demonstrated no cytotoxicity. Subcutaneous implantation into BALB/cJ mice indicated good biocompatibility in vivo. The biodegradability and biocompatibility of EPSHU together make it a promising candidate for drug delivery applications that demand carrier gel degradation within months. PMID:26814023

  12. Synthesis and biocompatibility of a biodegradable and functionalizable thermo-sensitive hydrogel.

    PubMed

    Sinha, Mantosh K; Gao, Jin; Stowell, Chelsea E T; Wang, Yadong

    2015-09-01

    Injectable thermal gels are a useful tool for drug delivery and tissue engineering. However, most thermal gels do not solidify rapidly at body temperature (37°C). We addressed this by synthesizing a thermo-sensitive, rapidly biodegrading hydrogel. Our hydrogel, poly(ethylene glycol)-co-poly(propanol serinate hexamethylene urethane) (EPSHU), is an ABA block copolymer comprising A, methoxy poly ethylene glycol group and B, poly (propanol L-serinate hexamethylene urethane). EPSHU was characterized by gel permeation chromatography for molecular weight and (1)H NMR and Fourier transformed infrared for structure. Rheological studies measured the phase transition temperature. In vitro degradation in cholesterol esterase and in Dulbecco's phosphate buffered saline (DPBS) was tracked using the average molecular weight measured by gel permeation chromatography. LIVE/DEAD and resazurin reduction assays performed on NIH 3T3 fibroblasts exposed to EPSHU extracts demonstrated no cytotoxicity. Subcutaneous implantation into BALB/cJ mice indicated good biocompatibility in vivo. The biodegradability and biocompatibility of EPSHU together make it a promising candidate for drug delivery applications that demand carrier gel degradation within months. PMID:26814023

  13. Synthesis and characterization of highly-magnetic biodegradable poly(D,L-lactide-co-glycolide) nanospheres.

    SciTech Connect

    Liu, X.; Kaminski, M. D.; Chen, H.; Torno, M.; Taylor, L.; Rosengart, A. J.; Univ. of Chicago

    2007-05-14

    The objective of this study was to develop high magnetization, biodegradable/biocompatible polymer-coated magnetic nanospheres for biomedical applications. Magnetic spheres were prepared by a modified single oil-in-water emulsion-solvent evaporation method utilizing highly-concentrated hydrophobic magnetite and poly(d,l lactide-co-glycolide) (PLGA). Hydrophobic magnetite prepared using oleic acid exhibited high magnetite concentrations (84 wt.%) and good miscibility with biopolymer solvents to form a stable oily suspension. The oily suspension was then emulsified within an aqueous solution containing poly(vinyl alcohol). After rapid evaporation of the organic solvent, we obtained solid magnetic nanospheres. We characterized these spheres in terms of external morphology, microstructure, size and zeta potential, magnetite content and distribution within the nanospheres, and magnetic properties. The results showed good encapsulation where the magnetite distorted the smooth surface morphology only at the highest magnetite concentrations. The mean diameter was 360-370 nm with polydispersity indices of 0.12-0.20. We obtained high magnetite content (40-60%) and high magnetization (26-40 emu/g). The high magnetization properties were obtained while leaving sufficient polymer to retain drugs making these biodegradable spheres suitable as a potential platform for the design of magnetically-guided drug delivery and other in vivo biomagnetic applications.

  14. New biodegradable dextran-based hydrogels for protein delivery: Synthesis and characterization.

    PubMed

    Pacelli, Settimio; Paolicelli, Patrizia; Casadei, Maria Antonietta

    2015-08-01

    A new derivative of dextran grafted with polyethylene glycol methacrylate through a carbonate bond (DEX-PEG-MA) has been synthesized and characterized. The photo-crosslinking reaction of DEX-PEG-MA allowed the obtainment of biodegradable networks tested for their mechanical and release properties. The new hydrogels were compared with those made of dextran methacrylate (DEX-MA), often employed as drug delivery systems of small molecules. The inclusion of PEG as a spacer created additional interactions among the polymeric chains improving the extreme fragility and lack of hardness typical of gels made of DEX-MA. Moreover, the different behavior in terms of swelling and degradability of the networks was able to affect the release of a model macromolecule over time, making DEX-PEG-MA matrices suitable candidates for the delivery of high molecular weight peptides. Interestingly, the combination of the two dextran derivatives showed intermediate ability to modulate the release of high molecular weight macromolecules. PMID:25933541

  15. Synthesis and characterization of a novel polymer-ceramic system for biodegradable composite applications.

    PubMed

    Yang, Liu; Wang, Jian; Hong, Jason; Santerre, J Paul; Pilliar, Robert M

    2003-09-01

    The objective of this study was to develop a biodegradable polymer resin that could be used for the fabrication of an interpenetrating phase composite (IPC) made of porous calcium polyphosphate (CPP) and an organic polymer resin. The resin was synthesized from a polycarbonate-based divinyl oligomer and monomers containing ionic groups. The physical and chemical properties of the polymer resin and polycarbonate-based divinyl oligomer were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, and swelling studies. The in vitro degradation of the polymer resins was assessed using cholesterol esterase in a buffer solution at 37 degrees C for 3 weeks. Scanning electron microscopy of the degraded samples indicated that the hydrolysis of the resin was catalyzed by the enzyme. The relative interfacial shear strength between the polymer resin and the CPP ceramic was studied using a microbond test. The addition of ionic groups into the polymer resin chains appeared to improve the chemical bonding between the polymer and the CPP. Preliminary mechanical properties of the IPC were investigated by determining bending strength using a three point bending test. The data showed a sevenfold increase in strength over that of the monolithic CPP, and the addition of more ionic groups into the resin led to a higher bending strength for the newly formed CPP/polycarbonate resin system. Sample cross sections of the IPC examined using scanning electron microscopy suggested that the resin had infiltrated almost all of the pores of the CPP. The results of this study indicate that the IPC could potentially be used for fabricating novel biodegradable load-bearing implants. PMID:12918046

  16. Synthesis of piroxicam loaded novel electrospun biodegradable nanocomposite scaffolds for periodontal regeneration.

    PubMed

    Farooq, Ariba; Yar, Muhammad; Khan, Abdul Samad; Shahzadi, Lubna; Siddiqi, Saadat Anwar; Mahmood, Nasir; Rauf, Abdul; Qureshi, Zafar-ul-Ahsan; Manzoor, Faisal; Chaudhry, Aqif Anwar; ur Rehman, Ihtesham

    2015-11-01

    Development of biodegradable composites having the ability to suppress or eliminate the pathogenic micro-biota or modulate the inflammatory response has attracted great interest in order to limit/repair periodontal tissue destruction. The present report includes the development of non-steroidal anti-inflammatory drug encapsulated novel biodegradable chitosan (CS)/poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) electro-spun (e-spun) composite nanofibrous mats and films and study of the effect of heat treatment on fibers and films morphology. It also describes comparative in-vitro drug release profiles from heat treated and control (non-heat treated) nanofibrous mats and films containing varying concentrations of piroxicam (PX). Electrospinning was used to obtain drug loaded ultrafine fibrous mats. The physical/chemical interactions were evaluated by Fourier Transform Infrared (FT-IR) spectroscopy. The morphology, structure and pore size of the materials were investigated by scanning electron microscopy (SEM). The thermal behavior of the materials was investigated by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Control (not heat treated) and heat treated e-spun fibers mats and films were tested for in vitro drug release studies at physiological pH7.4 and initially, as per requirement burst release patterns were observed from both fibers and films and later sustained release profiles were noted. In vitro cytocompatibility was performed using VERO cell line of epithelial cells and all the synthesized materials were found to be non-cytotoxic. The current observations suggested that these materials are potential candidates for periodontal regeneration. PMID:26249571

  17. Biodegradable poly(terephthalate-co-phosphate)s: synthesis, characterization and drug-release properties

    PubMed Central

    Mao, Hai-Quan; Shipanova-Kadiyala, Irina; Zhao, Zhong; Dang, Wenbin; Brown, Angela; Leong, Kam W.

    2008-01-01

    To develop biodegradable polymers with favorable physicochemical and biological properties, we have synthesized a series of poly(terephthalate-co-phosphate)s using a two-step polycondensation. The diol 1,4-bis(2-hydroxyethyl) terephthalate was first reacted with ethylphosphorodichloridate (EOP), and then chain-extended with terephthaloyl chloride (TC). Incorporation of phosphate into the poly(ethylene terephthalate) backbone rendered the co-polymers soluble in chloroform and biodegradable, lowered the Tg, decreased the crystallinity and increased the hydrophilicity. With an EOP/TC molar feed ratio of 80 : 20, the polymer exhibited good film-forming property, yielding at 86.6 ± 1.6% elongation with an elastic modulus of 13.76 ± 2.66 MPa. This polymer showed a favorable toxicity profile in vitro and good tissue biocompatibility in the muscular tissue of mice. In vitro the polymer lost 21% of mass in 21 days, but only 20% for up to 4 months in vivo. It showed no deterioration of properties after sterilization by γ -irradiation at 2.5 Mrad on solid CO2. Release of FITC-BSA from the microspheres was diffusion-controlled and exceeded 80% completion in two days. Release of the hydrophobic cyclosporine-A from microspheres was however much more sustained and near zero-ordered, discharging 60% in 70 days. A limited structure–property relationship has been established for this co-polymer series. The co-polymers became more hydrolytically labile as the phosphate component (EOP) was increased and the side chains were switched from the ethoxy to the methoxy structure. Converting the methoxy group to a sodium salt further increased the degradation rate significantly. The chain rigidity as reflected in the Tg values of the co-polymers decreased according to the following diol structure in the backbone: ethylene glycol > 2-methylpropylene diol > 2,2-dimethylpropylene diol. The wide range of physicochemical properties obtainable from this co-polymer series should help the

  18. Synthesis and characterization of L-tyrosine based novel biodegradable polyphosphates and polyurethanes for biomaterial applications

    NASA Astrophysics Data System (ADS)

    Sen Gupta, Anirban

    2003-10-01

    Hydrolytically degradable synthetic polymers developed from natural metabolite monomers play an extremely significant role in the area of biomaterial applications because of their potential biodegradability with minimal toxicity. Natural L-amino acids, being important natural metabolites, have been investigated for development of such polymers. Homopolymers of L-amino acids, through such investigations, have generated results indicating only limited success, mainly due to several difficulties associated with their processing and fabrication. For example, most of the homopoly(amino acids) have been found to be sparingly soluble or insoluble in common organic solvents, making chemical processing of these polymers difficult. Also, because of the high degree of crystallinity of such polymers, they have been found to have very negligible glass transition but prominent melting at high temperature regions, thereby making thermal processing of these polymers difficult. Such practical difficulties have been traced back to the highly ordered amidic(peptidic) nature of the polymer backbone. Hence, modification of the backbone structure of such polymers has been thought of as a way to circumvent such difficulties. The research described in this dissertation involves the development of natural amino-acid L-tyrosine-based polymers having alternate amide(peptide) and non-amide bonds in the polymer backbone. Hence they are aptly called "pseudo" poly(peptides). The introduction of the non-amide moiety in the backbone provides a way to induce, enhance and control several "bio-engineering" properties of the amino-acid based polymer, like, hydrolytic degradability, thermal transition temperatures, chemical solubility etc. that are pertinent to biomaterial applications. This dissertation describes stoichiometrically controlled solution polymerization processes that were developed to incorporate phosphoester and urethane moieties alternating with amide moieties in a predominantly L

  19. Biomass-derived chemicals: synthesis of biodegradable surfactant ether molecules from hydroxymethylfurfural.

    PubMed

    Arias, Karen S; Climent, Maria J; Corma, Avelino; Iborra, Sara

    2014-01-01

    A new class of biodegradable anionic surfactants with structures based on 5-alkoxymethylfuroate was prepared starting from 5-hydroxymethylfurfural (HMF), through a one-pot-two-steps process which involves the selective etherification of HMF with fatty alcohols using heterogeneous solid acid, followed by a highly selective oxidation of the formyl group with a gold catalyst. The etherification step was optimized using aluminosilicates as acid catalysts with different pore topologies (H-Beta, HY, Mordenite, ZSM-5, ITQ-2, and MCM-41), different active sites (Bronsted or Lewis) and different adsorption properties. It was shown that highly hydrophobic defect-free H-Beta zeolites with Si/Al ratios higher than 25 are excellent acid catalysts to perform the selective etherification of HMF with fatty alcohols, avoiding the competitive self-etherification of HMF. Moreover, the 5-alkoxymethylfurfural derivatives obtained can be selectively oxidized to the corresponding furoic salts in excellent yield using Au/CeO2 as catalyst and air as oxidant, at moderated temperatures. Both H-Beta zeolite and Au/CeO2 could be reused several times without loss of activity. PMID:24106062

  20. Synthesis, characterization and antibacterial activity of biodegradable starch/PVA composite films reinforced with cellulosic fibre.

    PubMed

    Priya, Bhanu; Gupta, Vinod Kumar; Pathania, Deepak; Singha, Amar Singh

    2014-08-30

    Cellulosic fibres reinforced composite blend films of starch/poly(vinyl alcohol) (PVA) were prepared by using citric acid as plasticizer and glutaraldehyde as the cross-linker. The mechanical properties of cellulosic fibres reinforced composite blend were compared with starch/PVA crossed linked blend films. The increase in the tensile strength, elongation percentage, degree of swelling and biodegradability of blend films was evaluated as compared to starch/PVA crosslinked blend films. The value of different evaluated parameters such as citric acid, glutaraldehyde and reinforced fibre to starch/PVA (5:5) was found to be 25 wt.%, 0.100 wt.% and 20 wt.%, respectively. The blend films were characterized using Fourier transform-infrared spectrophotometry (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA/DTA/DTG). Scanning electron microscopy illustrated a good adhesion between starch/PVA blend and fibres. The blend films were also explored for antimicrobial activities against pathogenic bacteria like Staphylococcus aureus and Escherichia coli. The results confirmed that the blended films may be used as exceptional material for food packaging. PMID:24815414

  1. Nanocomposite scaffold fabrication by incorporating gold nanoparticles into biodegradable polymer matrix: Synthesis, characterization, and photothermal effect.

    PubMed

    Abdelrasoul, Gaser N; Farkas, Balazs; Romano, Ilaria; Diaspro, Alberto; Beke, Szabolcs

    2015-11-01

    Nanoparticle incorporation into scaffold materials is a valuable route to deliver various therapeutic agents, such as drug molecules or large biomolecules, proteins (e.g. DNA or RNA) into their targets. In particular, gold nanoparticles (Au NPs) with their low inherent toxicity, tunable stability and high surface area provide unique attributes facilitating new delivery strategies. A biodegradable, photocurable polymer resin, polypropylene fumarate (PPF) along with Au NPs were utilized to synthesize a hybrid nanocomposite resin, directly exploitable in stereolithography (SL) processes. To increase the particles' colloidal stability, the Au NP nanofillers were coated with polyvinyl pyrrolidone (PVP). The resulting resin was used to fabricate a new type of composite scaffold via mask projection excimer laser stereolithography. The thermal properties of the nanocomposite scaffolds were found to be sensitive to the concentration of NPs. The mechanical properties were augmented by the NPs up to 0.16μM, though further increase in the concentration led to a gradual decrease. Au NP incorporation rendered the biopolymer scaffolds photosensitive, i.e. the presence of Au NPs enhanced the optical absorption of the scaffolds as well, leading to possible localized temperature rise when irradiated with 532nm laser, known as the photothermal effect. PMID:26249594

  2. Chitosan-isoniazid conjugates: Synthesis, evaluation of tuberculostatic activity, biodegradability and toxicity.

    PubMed

    Berezin, Alexander S; Skorik, Yury A

    2015-08-20

    Novel water-soluble chitosan-isoniazid conjugates were synthesized by two methods: (1) the carbodiimide method using isoniazid (INH) and N-(2-carboxyethyl)chitosan (CEC), and (2) the reaction between INH and N-(3-chloro-2-hydroxypropyl)chitosan (CHPC). The solubility of the conjugates under physiological conditions was enhanced by phosphorylation. Method (1) is preferable in terms of obtaining conjugates with a high content of active substance; depending on reaction conditions, the degree of substitution in the INH-CEC conjugates varies from 0.08 to 0.39. Ultrasound treatment increased the reaction rate by a factor of 1.3-1.5, but caused partial degradation of the polymer. Consecutive modification led to a considerable decrease in polymer biodegradability in the following order: chitosan>CEC or CHPC>conjugate. In vitro screening of the antimicrobial activity against Mycobacterium tuberculosis H37Rv demonstrated a comparable or slightly higher minimum inhibitory concentration for conjugates than for INH itself (0.20, 0.25, and 1.05 μg INH/mL for INH, CEC-INH, and CHPC-INH, respectively). A slug mucosal irritation test employing Limax flavus revealed a lower toxicity for the conjugates than for INH by a factor of 3-4; the most noticeable toxicity decrease was observed for the conjugates obtained by method (1). Studies of acute toxicity in mice revealed a 3-4-fold increase in median lethal dose for the conjugates compared with INH (LD50 210, 850, and 650 mg INH/kg for INH, CEC-INH, and CHPC-INH, respectively). PMID:25965488

  3. Exploring mild enzymatic sustainable routes for the synthesis of bio-degradable aromatic-aliphatic oligoesters.

    PubMed

    Pellis, Alessandro; Guarneri, Alice; Brandauer, Martin; Acero, Enrique Herrero; Peerlings, Henricus; Gardossi, Lucia; Guebitz, Georg M

    2016-05-01

    The application of Candida antarctica lipase B in enzyme-catalyzed synthesis of aromatic-aliphatic oligoesters is here reported. The aim of the present study is to systematically investigate the most favorable conditions for the enzyme catalyzed synthesis of aromatic-aliphatic oligomers using commercially available monomers. Reaction conditions and enzyme selectivity for polymerization of various commercially available monomers were considered using different inactivated/activated aromatic monomers combined with linear polyols ranging from C2 to C12 . The effect of various reaction solvents in enzymatic polymerization was assessed and toluene allowed to achieve the highest conversions for the reaction of dimethyl isophthalate with 1,4-butanediol and with 1,10-decanediol (88 and 87% monomer conversion respectively). Mw as high as 1512 Da was obtained from the reaction of dimethyl isophthalate with 1,10-decanediol. The obtained oligomers have potential applications as raw materials in personal and home care formulations, for the production of aliphatic-aromatic block co-polymers or can be further functionalized with various moieties for a subsequent photo- or radical polymerization. PMID:26762794

  4. Biocatalytic synthesis and in vitro release of biodegradable linear polyesters with pendant ketoprofen.

    PubMed

    Wang, Hai-Yang; Zhang, Wei-Wei; Wang, Na; Li, Chao; Li, Kun; Yu, Xiao-Qi

    2010-12-13

    Enzyme-catalyzed polycondensation for the synthesis of polyester prodrugs of ketoprofen was reported. Lipase acrylic resin from Candida antarctica (CAL-B) was used to synthesize the linear polyesters with pendent ketoprofen groups based on ketoprofen glycerol ester, poly(ethylene glycol), and divinyl sebacate. The products were characterized by GPC and (1)H NMR. The results indicated that the molecular weight and yields of the polyesters depend on experimental conditions such as temperature and feed ratio. The in vitro study showed that the drug release from the polyester was slow under physiological conditions, which indicated that the polyester could be a promising prodrug with extended pharmacological effects by delayed release of ketoprofen. PMID:21053944

  5. One-step synthesis, biodegradation and biocompatibility of polyesters based on the metabolic synthon, dihydroxyacetone.

    PubMed

    Korley, Julius N; Yazdi, Sara; McHugh, Kevin; Kirk, James; Anderson, James; Putnam, David

    2016-08-01

    The one-step synthesis of a polyester family containing dihydroxyacetone is described along with a quantitative analysis of in vitro/in vivo degradation kinetics and initial biocompatibility. Polyesters were synthesized by combining dihydroxyacetone, which is a diol found in the eukaryotic glucose metabolic pathway, with even-carbon aliphatic diacids (adipic, suberic, sebacic) represented in the long-chain alpha carboxylic acid metabolic pathway, by Schӧtten-Baumann acylation. We show that by using a crystalline monomeric form of dihydroxyacetone, well-defined polyesters can be formed in one step without protection and deprotection strategies. Both diacid length and polyester molecular weight were varied to influence polymer physical and thermal properties. Polyesters were generated with number-averaged (Mn) molecular weights ranging from 2200-11,500. Polydispersities were consistent with step-growth polymerization and ranged from 2 to 2.6. The melting (Tm) and recrystallization (Tc) temperatures were impacted in an unpredictable manner. Thermal transitions for the polyesters were highest for the adipic acid followed by suberic acid and sebacic acid, respectively. It was shown that the thermal response of the DHA-based polyesters was influenced by both the diacid length and molecular weight. In vitro degradation studies revealed first-order weight loss kinetics, the molecular weight loss followed first order kinetics with 25%-40% of the original mass remaining after 8 weeks. In vivo testing over 16 weeks highlighted that mass loss ranged from ∼70% to ∼6% depending upon initial molecular weight and diacid length. Histological analysis revealed rapid resolution of both acute and chronic inflammatory responses, normal foreign body responses were observed and no inflammation was present after week 4. This one-step synthesis proved robust with unique copolymers warranting further study as potential biomaterials. PMID:27179432

  6. Green synthesis of colloid silver nanoparticles and resulting biodegradable starch/silver nanocomposites.

    PubMed

    Cheviron, Perrine; Gouanvé, Fabrice; Espuche, Eliane

    2014-08-01

    Environmentally friendly silver nanocomposite films were prepared by an ex situ method consisting firstly in the preparation of colloidal silver dispersions and secondly in the dispersion of the as-prepared nanoparticles in a potato starch/glycerol matrix, keeping a green chemistry process all along the synthesis steps. In the first step concerned with the preparation of the colloidal silver dispersions, water, glucose and soluble starch were used as solvent, reducing agent and stabilizing agent, respectively. The influences of the glucose amount and reaction time were investigated on the size and size distribution of the silver nanoparticles. Two distinct silver nanoparticle populations in size (diameter around 5 nm size for the first one and from 20 to 50 nm for the second one) were distinguished and still highlighted in the potato starch/glycerol based nanocomposite films. It was remarkable that lower nanoparticle mean sizes were evidenced by both TEM and UV-vis analyses in the nanocomposites in comparison to the respective colloidal silver dispersions. A dispersion mechanism based on the potential interactions developed between the nanoparticles and the polymer matrix and on the polymer chain lengths was proposed to explain this morphology. These nanocomposite film series can be viewed as a promising candidate for many applications in antimicrobial packaging, biomedicines and sensors. PMID:24751276

  7. Editorial: Biodegradable Materials

    PubMed Central

    Schaschke, Carl; Audic, Jean-Luc

    2014-01-01

    This Special Issue “Biodegradable Materials” features research and review papers concerning recent advances on the development, synthesis, testing and characterisation of biomaterials. These biomaterials, derived from natural and renewable sources, offer a potential alternative to existing non-biodegradable materials with application to the food and biomedical industries amongst many others. In this Special Issue, the work is expanded to include the combined use of fillers that can enhance the properties of biomaterials prepared as films. The future application of these biomaterials could have an impact not only at the economic level, but also for the improvement of the environment. PMID:25421242

  8. Methacrylated monosaccharides as the modifiers for carbochain polymers: Synthesis, mechanical/thermal properties and biodegradability of hybrids

    NASA Astrophysics Data System (ADS)

    Yakushev, P.; Bershtein, V.; Bukowska-Śluz, I.; Sobiesiak, M.; Gawdzik, B.

    2016-05-01

    Methacrylated derivatives of glucose (MGLU) and galactose (MGAL) were synthesized by the procedure described by Vogel, and their copolymers with methyl methacrylate (MMA) and MMA/N-vinyl pyrrolidone (MMA/NVP) (1:1) mixture were obtained with the aim to modify some properties of carbochain polymers, in particular to generate their biodegradability. These hybrids of synthetic and natural products, with 10, 20 or 30 wt. % modifiers, were characterized by DMA and TGA methods and in the biodegradation tests. Increasing Tg values by 20-30°C was registered in all cases whereas thermal stability was improved only for PMMA due to modification. On the contrary, only for hybrids based on hygroscopic MMA/NVP copolymer the essential biodegradability could be generated.

  9. Coordination Polymer: Synthesis, Spectral Characterization and Thermal Behaviour of Starch-Urea Based Biodegradable Polymer and Its Polymer Metal Complexes

    PubMed Central

    Malik, Ashraf; Parveen, Shadma; Ahamad, Tansir; Alshehri, Saad M.; Singh, Prabal Kumar; Nishat, Nahid

    2010-01-01

    A starch-urea-based biodegradable coordination polymer modified by transition metal Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) was prepared by polycondensation of starch and urea. All the synthesized polymeric compounds were characterized by Fourier transform-infrared spectroscopy (FT-IR), 1H-NMR spectroscopy, 13C-NMR spectroscopy, UV-visible spectra, magnetic moment measurements, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA). The results of electronic spectra and magnetic moment measurements indicate that Mn(II), Co(II), and Ni(II) complexes show octahedral geometry, while Cu(II) and Zn(II) complexes show square planar and tetrahedral geometry, respectively. The thermogravimetric analysis revealed that all the polymeric metal complexes are more thermally stable than the parental ligand. In addition, biodegradable studies of all the polymeric compounds were also carried out through ASTM standards of biodegradable polymers by CO2 evolution method. PMID:20414461

  10. Synthesis and evaluation of MgF2 coatings by chemical conversion on magnesium alloys for producing biodegradable orthopedic implants of temporary use

    NASA Astrophysics Data System (ADS)

    Casanova, P. Y.; Jaimes, K. J.; Parada, N. J.; Hernández-Barrios, C. A.; Aparicio, M.; Viejo, F.; Coy, A. E.

    2013-11-01

    The aim of the present work was the synthesis of biodegradable MgF2 coatings by chemical conversion on the commercial Elektron 21 and AZ91D magnesium alloys, in aqueous HF solutions for different concentrations and temperatures. The chemical composition and morphology of the coatings were analyzed by scanning electron microscopy (SEM-EDX) and X-ray diffraction (XRD). On the other hand, their corrosion behavior was evaluated by gravimetric and electrochemical measurements in Hank's solution at 37°C for different immersion times. The experimental results revealed that chemical conversion in HF produced MgF2 coatings which corrosion resistance was enhanced by increasing the HF concentration. Further, the microstructure and composition of the base alloy played a key role on the growth and degradation mechanisms of the MgF2 coatings.

  11. Synthesis, anti-oxidant activity, and biodegradability of a novel recombinant polysaccharide derived from chitosan and lactose.

    PubMed

    Guo, Ming; Ma, Yanfei; Wang, Chunge; Liu, Hongzhi; Li, Qian; Fei, Meng

    2015-03-15

    A novel recombinant polysaccharide (RP) based on polysaccharide-disaccharide was synthesized from oligo-chitosan (oligo-CS) and reducing lactose using Maillard reaction with the yield of 85.1%. Chemical structure and thermal stability of RP was characterized by Fourier transform infrared spectrum (FT-IR), solid-state nuclear magnetic resonance spectroscopy (CP/MAS (13)C-NMR), and thermo gravimetric analysis (TGA). The anti-oxidant activity of RP was preliminarily investigated by its scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Biodegradability of RP was also examined by the observation of growth status of Aspergillus niger colony. It was demonstrated that RP achieved excellent radical-scavenging efficiency (>80%) at high concentrations of DPPH and its scavenging ability was superior to that of CS, suggesting that anti-oxidant property of CS was remarkably promoted by chemical modification with reducing lactose via Maillard reaction. And biodegradation test revealed that RP had better biodegradability than CS. PMID:25542127

  12. Synthesis and self-assembly behavior of a biodegradable and sustainable soybean oil-based copolymer nanomicelle

    PubMed Central

    2014-01-01

    Herein, we report a novel amphiphilic biodegradable and sustainable soybean oil-based copolymer (SBC) prepared by grafting hydrophilic and biocompatible hydroxyethyl acrylate (HEA) polymeric segments onto the natural hydrophobic soybean oil chains. FTIR, H1-NMR, and GPC measurements have been used to investigate the molecular structure of the obtained SBC macromolecules. Self-assembly behaviors of the prepared SBC in aqueous solution have also been extensively evaluated by fluorescence spectroscopy and transmission electron microscopy. The prepared SBC nanocarrier with the size range of 40 to 80 nm has a potential application in the biomedical field. PMID:25170329

  13. Synthesis, characterization and antioxidant activity of a novel electroactive and biodegradable polyurethane for cardiac tissue engineering application.

    PubMed

    Baheiraei, Nafiseh; Yeganeh, Hamid; Ai, Jafar; Gharibi, Reza; Azami, Mahmoud; Faghihi, Faezeh

    2014-11-01

    There has been a growing trend towards applying conducting polymers for electrically excitable cells to increase electrical signal propagation within the cell-loaded substrates. A novel biodegradable electroactive polyurethane containing aniline pentamer (AP-PU) was synthesized and fully characterized by spectroscopic methods. To tune the physico-chemical properties and biocompatibility, the AP-PU was blended with polycaprolactone (PCL). The presence of electroactive moieties and the electroactivity behavior of the prepared films were confirmed by UV-visible spectroscopy and cyclic voltammetry. A conventional four probe analysis demonstrated the electrical conductivity of the films in the semiconductor range (~10(-5)S/cm). MTT assays using L929 mouse fibroblast and human umbilical vein endothelial cells (HUVECs) showed that the prepared blend (PB) displayed more cytocompatibility compared with AP-PU due to the introduction of a biocompatible PCL moiety. The in vitro cell culture also confirmed that PB was as supportive as tissue culture plate. The antioxidant activity of the AP-PU was proved using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay by employing UV-vis spectroscopy. In vitro degradation tests conducted in phosphate-buffered saline, pH7.4 and pH5.5, proved that the films were also biodegradable. The results of this study have highlighted the potential application of this bioelectroactive polyurethane as a platform substrate to study the effect of electrical signals on cell activities and to direct desirable cell function for tissue engineering applications. PMID:25280676

  14. Biodegradable radiopaque iodinated poly(ester urethane)s containing poly(ε-caprolactone) blocks: synthesis, characterization, and biocompatibility.

    PubMed

    Sang, Lin; Wei, Zhiyong; Liu, Keliang; Wang, Xinhui; Song, Kedong; Wang, Hong; Qi, Min

    2014-04-01

    Biodegradable radiopaque iodinated poly(ester-urethane) (I-PU), consisting of poly(ε-caprolactone) (PCL) diol and iodinated bisphenol A (IBPA), has been successfully synthesized via a coupling reaction of PCL-diisocyanate and IBPA with varying compositions. The IBPA with four iodine atoms per molecule was applied as a chain extender to endow the I-PUs with intrinsic X-ray visibility. The chemical structure and molecular weights of I-PUs were characterized by Fourier transform infrared spectroscopy (FT-IR), proton-nuclear magnetic resonance, and gel permeation chromatography (GPC). The effects of IBPA on the physical properties of I-PUs were systematically studied by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and wide-angle X-ray diffraction (WAXD). The DSC results showed that the crystallization of PCL segments in I-PUs was restrained with increasing amount of IBPA, which was also confirmed by WAXD. In the X-radiography analysis, all the synthesized I-PUs exhibited high radiopacity compared with an aluminum wedge of equivalent thickness. Enzymatic degradation tests showed that the incorporation of IBPA prolonged the degradation of I-PUs and distinct mass loss and degradation happened in the third month. Basic cytocompatibility conducted using rat adipose-derived cells proved that all the I-PUs and their biodegradation products were nontoxic. The radiopaque I-PUs is expected to possess a significant advantage over the traditional polymer counterparts in some related biomedical fields. PMID:23640806

  15. Synthesis and 3D printing of biodegradable polyurethane elastomer by a water-based process for cartilage tissue engineering applications.

    PubMed

    Hung, Kun-Che; Tseng, Ching-Shiow; Hsu, Shan-Hui

    2014-10-01

    Biodegradable materials that can undergo degradation in vivo are commonly employed to manufacture tissue engineering scaffolds, by techniques including the customized 3D printing. Traditional 3D printing methods involve the use of heat, toxic organic solvents, or toxic photoinitiators for fabrication of synthetic scaffolds. So far, there is no investigation on water-based 3D printing for synthetic materials. In this study, the water dispersion of elastic and biodegradable polyurethane (PU) nanoparticles is synthesized, which is further employed to fabricate scaffolds by 3D printing using polyethylene oxide (PEO) as a viscosity enhancer. The surface morphology, degradation rate, and mechanical properties of the water-based 3D-printed PU scaffolds are evaluated and compared with those of polylactic-co-glycolic acid (PLGA) scaffolds made from the solution in organic solvent. These scaffolds are seeded with chondrocytes for evaluation of their potential as cartilage scaffolds. Chondrocytes in 3D-printed PU scaffolds have excellent seeding efficiency, proliferation, and matrix production. Since PU is a category of versatile materials, the aqueous 3D printing process developed in this study is a platform technology that can be used to fabricate devices for biomedical applications. PMID:24729580

  16. Synthesis of biodegradable Mg-Zn alloy using mechanical alloying: Effect of ball to powder weight ratio

    NASA Astrophysics Data System (ADS)

    Zuhailawati, Hussain; Salleh, Emee Marina; Ramakrishnan, Sivakumar

    2016-07-01

    The aim of this work was to study the effect of ball to powder weight ratio (BPR) on biodegradable binary magnesium-zinc (Mg-Zn) alloy synthesized using mechanical alloying. A powder mixture of Mg-5wt%Zn was milled in a planetary mill under argon atmosphere using a stainless steel container and balls. Milling process was carried out at 200 rpm for 5 hours using various BPR (i.e. 5:1, 10:1, 15:1, 20:1). Then, as milled powder was compacted under 400 MPa and sintered in a tube furnace at 300 °C in argon flow for an hour. The sintered density and microhardness of the alloy increased as BPR increased up to 15:1. However a further increasing showed a reduction in both density and microhardness which due to enlargement of crystallite and particle which resulted from the excessive internal energy during mechanical alloying.

  17. A new peptide-based urethane polymer: synthesis, biodegradation, and potential to support cell growth in vitro

    PubMed Central

    Zhang, Jian Ying; Beckman, Eric J.; Piesco, Nicholas P.; Agarwal, Sudha

    2016-01-01

    A novel non-toxic biodegradable lysine-di-isocyanate (LDI)-based urethane polymer was developed for use in tissue engineering applications. This matrix was synthesized with highly purified LDI made from the lysine diethylester. The ethyl ester of LDI was polymerized with glycerol to form a prepolymer. LDI–glycerol prepolymer when reacted with water foamed with the liberation of CO2 to provide a pliable spongy urethane polymer. The LDI–glycerol matrix degraded in aqueous solutions at 100, 37, 22, and 4°C at a rate of 27.7, 1.8, 0.8, and 0.1 mM per 10 days, respectively. Its thermal stability in water allowed its sterilization by autoclaving. The degradation of the LDI–glycerol polymer yielded lysine, ethanol, and glycerol as breakdown products. The degradation products of LDI–glycerol polymer did not significantly affect the pH of the solution. The glass transition temperature (Tg) of this polymer was found to be 103.4°C. The physical properties of the polymer network were found to be adequate to support the cell growth in vitro, as evidenced by the fact that rabbit bone marrow stromal cells (BMSC) attached to the polymer matrix and remained viable on its surface. Culture of BMSC on LDI–glycerol matrix for long durations resulted in the formation of multilayered confluent cultures, a characteristic typical of bone cells. Furthermore, cells grown on LDI–glycerol matrix did not differ phenotypically from the cells grown on the tissue culture polystyrene plates as assessed by the cell growth, and expression of mRNA for collagen type I, and transforming growth factor-β1 (TGF-β1). The observations suggest that biodegradable peptide-based urethane polymers can be synthesized which may pave their way for possible use in tissue engineering applications. PMID:10811306

  18. Greener Techniques for the Synthesis of Silver Nanoparticles Using Plant Extracts, Enzymes, Bacteria, Biodegradable Polymers, and Microwaves

    EPA Science Inventory

    The use of silver nanoparticles (AgNPs) is gaining in popularity due to silver’s antibacterial properties. Conventional methods for AgNP synthesis require dangerous chemicals and large quantities of energy (heat) and can result in formation of hazardous by-products. This article ...

  19. Enzymatic synthesis and evaluation of new novel omega-pentadecalactone polymers for the production of biodegradable microspheres.

    PubMed

    Thompson, Colin J; Hansford, Denise; Higgins, Sean; Hutcheon, Gillian A; Rostron, Chris; Munday, Dale L

    2006-03-01

    Two novel co-polymers based on omega-pentadecalactone were enzymatically synthesized by a combination of ring-opening polymerization and polycondensation. Modified literature procedures enabled the production of the semi-crystalline materials with suitable molecular weights and melting characteristics. Microspheres were produced using an emulsion solvent evaporation method over a range of variables including manufacturing temperature, stirring speed and duration, surfactant concentration, continuous and disperse phase volume and polymer amount to establish how each variable affected the morphological characteristics of the microspheres. Results demonstrated that changes in emulsion viscosity influenced microsphere size. For polymer SH-L333, the microsphere surface was either smooth or porous depending on the manufacturing temperature used. For polymer SH-L334 the microsphere surface was rough or porous regardless of manufacturing temperature. This was possibly due to several combined factors including molecular weight and the greater hydrophilic nature of SH-L334. These new polymers have the potential for the manufacture of drug-loaded biodegradable microspheres for modified release drug delivery. PMID:16754377

  20. Synthesis and click chemistry of a new class of biodegradable polylactide towards tunable thermo-responsive biomaterials†

    PubMed Central

    Zhang, Quanxuan; Ren, Hong; Baker, Gregory L.

    2014-01-01

    A new class of clickable and biodegradable polylactide was designed and prepared via bulk polymerization of 3,6-dipropargyloxymethyl-1,4-dioxane-2,5-dione (1) which was synthesized from easily accessible propargyloxylactic acid (5). A homopolymer of 1 and random copolymer of 1 with l-lactide were obtained as amorphous materials and exhibit low Tg of 8.5 and 34 °C, respectively, indicating their promising potentials for biomedical applications. The statistical nature of random copolymers was investigated by DSC analysis and 13C NMR spectroscopy, which implies the random distribution of terminal alkyne groups along the back bone of copolymers. The efficient click post-modification of this new class of polylactide with alkyl and mPEG azides affords novel hydrophilic biomaterials, which exhibit reversible thermo-responsive properties as evidenced by their tunable LCST ranging from 22 to 69 °C depending on the balance of the incorporated hydrophilic/hydrophobic side chains. These results indicate the generality of this new class of clickable polylactide in preparing novel smart biomaterials in a simple and efficient manner via click chemistry. PMID:25685199

  1. Saponins: a renewable and biodegradable surfactant from its microwave-assisted extraction to the synthesis of monodisperse lattices.

    PubMed

    Schmitt, C; Grassl, B; Lespes, G; Desbrières, J; Pellerin, V; Reynaud, S; Gigault, J; Hackley, V A

    2014-03-10

    Synthetic surfactants are widely used in emulsion polymerization, but it is increasingly desirable to replace them with naturally derived molecules with a reduced environmental burden. This study demonstrates the use of saponins as biodegradable and renewable surfactants for emulsion polymerization. This chemical has been extracted from soapnuts by microwave assisted extraction and characterized in terms of surfactant properties prior to emulsion polymerization. The results in terms of particle size distribution and morphology control have been compared to those obtained with classical nonionic (NP40) or anionic (SDS) industrial surfactants. Microwave-extracted saponins were able to lead to latexes as stable as standard PS latex, as shown by the CMC and CCC measurements. The saponin-stabilized PS particles have been characterized in terms of particle size and distribution by Dynamic Light Scattering and Asymmetrical Flow Field Flow Fractionation. Monomodal and monodispersed particles ranging from 250 to 480 nm in terms of diameter with a particle size distribution below 1.03 have been synthesized. PMID:24443771

  2. Synthesis and Characterization of Injectable, Biodegradable, Phosphate-Containing, Chemically Cross-Linkable, Thermoresponsive Macromers for Bone Tissue Engineering

    PubMed Central

    2015-01-01

    Novel, injectable, biodegradable macromer solutions that form hydrogels when elevated to physiologic temperature via a dual chemical and thermo-gelation were fabricated and characterized. A thermogelling, poly(N-isopropylacrylamide)-based macromer with pendant phosphate groups was synthesized and subsequently functionalized with chemically cross-linkable methacrylate groups via degradable phosphate ester bonds, yielding a dual-gelling macromer. These dual-gelling macromers were tuned to have transition temperatures between room temperature and physiologic temperature, allowing them to undergo instantaneous thermogelation as well as chemical gelation when elevated to physiologic temperature. Additionally, the chemical cross-linking of the hydrogels was shown to mitigate hydrogel syneresis, which commonly occurs when thermogelling materials are raised above their transition temperature. Finally, degradation of the phosphate ester bonds of the cross-linked hydrogels yielded macromers that were soluble at physiologic temperature. Further characterization of the hydrogels demonstrated minimal cytotoxicity of hydrogel leachables as well as in vitro calcification, making these novel, injectable macromers promising materials for use in bone tissue engineering. PMID:24758298

  3. Sulfur Nanoparticles Synthesis and Characterization from H2S Gas, Using Novel Biodegradable Iron Chelates in W/O Microemulsion

    NASA Astrophysics Data System (ADS)

    Deshpande, Aniruddha S.; Khomane, Ramdas B.; Vaidya, Bhalchandra K.; Joshi, Renuka M.; Harle, Arti S.; Kulkarni, Bhaskar D.

    2008-06-01

    Sulfur nanoparticles were synthesized from hazardous H2S gas using novel biodegradable iron chelates in w/o microemulsion system. Fe3+ malic acid chelate (0.05 M aqueous solution) was studied in w/o microemulsion containing cyclohexane, Triton X-100 and n-hexanol as oil phase, surfactant, co-surfactant, respectively, for catalytic oxidation of H2S gas at ambient conditions of temperature, pressure, and neutral pH. The structural features of sulfur nanoparticles have been characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), diffused reflectance infra-red Fourier transform technique, and BET surface area measurements. XRD analysis indicates the presence of α-sulfur. TEM analysis shows that the morphology of sulfur nanoparticles synthesized in w/o microemulsion system is nearly uniform in size (average particle size 10 nm) and narrow particle size distribution (in range of 5 15 nm) as compared to that in aqueous surfactant systems. The EDS analysis indicated high purity of sulfur (>99%). Moreover, sulfur nanoparticles synthesized in w/o microemulsion system exhibit higher antimicrobial activity (against bacteria, yeast, and fungi) than that of colloidal sulfur.

  4. Synthesis and self-assembly of biodegradable polyethylene glycol-poly (lactic acid) diblock copolymers as polymersomes for preparation of sustained release system of doxorubicin

    PubMed Central

    Alibolandi, Mona; Sadeghi, Fatemeh; Sazmand, Seyed Hossein; Shahrokhi, Seyed Mohammad; Seifi, Mahmoud; Hadizadeh, Farzin

    2015-01-01

    Introduction: The copolymer of polyethylene glycol (PEG) and polyesters has many interesting properties, such as amphiphilicity, biocompatibility, biodegradability, and self-assembly in an aqueous environment. Diblock copolymers of PEG-polyester can form different structures such as micelles, polymersome, capsules or micro-container in an aqueous environment according to the length of their blocks. Materials and Methods: Herein, a series of poly (lactic acid) (PLA) and PEG diblock copolymers were synthesized through the ring-opening polymerization. The polymerization reaction and the copolymer structures were evaluated by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The corresponding copolymers were implemented for the formation of polymersome structures using film rehydration method. Impact of methoxy PEG chain length and hydrophobic weight fraction on particle size of polymersomes were studied, and the proper ones were selected for loading of doxorubicin (DOX) via pH gradient method. Results and Discussion: Results obtained from 1HNMR and GPC revealed that microwave irradiation is a simple and reliable method for the synthesis of PEG-PLA copolymers. Further analysis indicated the copolymer with relative molecular weight of PLA to PEG ratios of 3 or fEo ~ 25% produced the smallest size polymersomes. Polymersomes prepared from PEG5000 to PLA15000 were more capable in loading and sustained release of DOX than those prepared from PEG2000 to PLA6000. Conclusion: In conclusion copolymers of PEG/PLA with fOE ~25% and relatively higher molecular weight are more suitable for encapsulation and providing sustained release of DOX. PMID:26258054

  5. Effect of biodegradation and de novo matrix synthesis on the mechanical properties of valvular interstitial cell-seeded polyglycerol sebacate-polycaprolactone scaffolds.

    PubMed

    Sant, Shilpa; Iyer, Dharini; Gaharwar, Akhilesh K; Patel, Alpesh; Khademhosseini, Ali

    2013-04-01

    The development of living heart valves that grow with the patient is a promising strategy for heart valve replacements in pediatric patients. Despite active research in the field of tissue engineered heart valves there have been limited efforts to optimize the balance between biodegradation of the scaffolds and de novo extracellular matrix (ECM) synthesis by cells and study their consequences on the mechanical properties of the cell-seeded construct. This study investigates the effect of in vitro degradation and ECM secretion on the mechanical properties of hybrid polyester scaffolds. The scaffolds were synthesized from blends of fast degrading polyglycerol sebacate (PGS) and slowly degrading polycaprolactone (PCL). PGS-PCL scaffolds were electrospun using a 2:1 ratio of PGS to PCL. Accelerated hydrolytic degradation in 0.1 mM sodium hydroxide revealed 2-fold faster degradation of PGS-PCL scaffolds compared with PCL scaffolds. Thermal analysis and scanning electron microscopy demonstrated marginal change in PCL scaffold properties, while PGS-PCL scaffolds showed preferential mass loss of PGS and thinning of the individual fibers during degradation. Consequently, the mechanical properties of PGS-PCL scaffolds decreased gradually with no significant change for PCL scaffolds during accelerated degradation. Valvular interstitial cells (VICs) seeded on PGS-PCL scaffolds showed higher ECM protein secretion compared with PCL. Thus the mechanical properties of the cell-seeded PCL scaffolds did not change significantly compared with acellular scaffolds, probably due to slower degradation and ECM deposition by VICs. In contrast, the PGS-PCL scaffolds exhibited a gradual decrease in the mechanical properties of the acellular scaffolds due to degradation, which was compensated for by new matrix secreted by VICs seeded on the scaffolds. Our study demonstrated that the faster degrading PGS component of PGS-PCL accelerated the degradation rate of the scaffolds. VICs, on the other

  6. Synthesis of Biodegradable Macroporous Poly(l-lactide)/Poly(ε-caprolactone) Blend Using Oil-in-Eutectic-Mixture High-Internal-Phase Emulsions as Template.

    PubMed

    Pérez-García, María G; Gutiérrez, María C; Mota-Morales, Josué D; Luna-Bárcenas, Gabriel; Del Monte, Francisco

    2016-07-01

    We have demonstrated that l-lactide (LLA) forms a eutectic mixture with ε-caprolactone (CL) in a 30:70 mol ratio with a melting point of -19 °C. Taking advantage of the liquid nature and polarity at the LLA-CL eutectic mixture, we have formulated oil-in-eutectic-mixture high-internal-phase emulsions (HIPEs) by stepwise addition of the oil phase (tetradecane) into the continuous phase (mixture of surfactant and LLA-CL eutectic mixture) at room temperature and under stirring. The oil-in-LLA-CL-eutectic-mixture HIPEs were polymerized in the presence of both the organocatalysts 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and methanesulfonic acid (MSA) and the initiator benzyl alcohol (BnOH) at 37 °C and without the addition of any extra reagent or solvent in one single pot. The catalytic selectivities of DBU and MSA for the ring-opening polymerizations of LLA and CL, respectively, allowed the synthesis of macroporous poly(l-lactide)/poly(ε-caprolactone) blend materials. The resulting materials exhibited a macroporous morphology that resembled that of the HIPE internal-phase droplets used as templates. These materials proved effective as oil absorbents for oil/water separation with not only a noticeable performance, similar to that of conventional sorbents in terms of both selectivity and recyclability, but also unprecedented safe disposability, certainly of interest for applications in the cleanup of industrial oily wastewaters and oil spills, thanks to the biodegradable features of both poly(ε-caprolactone) and poly(l-lactide). PMID:27294287

  7. Biodegradable poly(ether ester urethane)urea elastomers based on poly(ether ester) triblock copolymers and putrescine: synthesis, characterization and cytocompatibility.

    PubMed

    Guan, Jianjun; Sacks, Michael S; Beckman, Eric J; Wagner, William R

    2004-01-01

    Polymers with elastomeric mechanical properties, tunable biodegradation properties and cytocompatibility would be desirable for numerous biomedical applications. Toward this end a series of biodegradable poly(ether ester urethane)urea elastomers (PEEUUs) based on poly(ether ester) triblock copolymers were synthesized and characterized. Poly(ether ester) triblock copolymers were synthesized by ring-opening polymerization of epsilon-caprolactone with polyethylene glycol (PEG). PEEUUs were synthesized from these triblock copolymers and butyl diisocyanate, with putrescine as a chain extender. PEEUUs exhibited low glass transition temperatures and possessed tensile strengths ranging from 8 to 20MPa and breaking strains from 325% to 560%. Increasing PEG length or decreasing poly(caprolactone) length in the triblock segment increased PEEUU water absorption and biodegradation rate. Human umbilical vein endothelial cells cultured in a medium supplemented with PEEUU biodegradation solution suggested a lack of degradation product cytotoxicity. Endothelial cell adhesion to PEEUUs was less than 60% of tissue culture polystyrene and was inversely related to PEEUU hydrophilicity. Surface modification of PEEUUs with ammonia gas radio-frequency glow discharge and subsequent immobilization of the cell adhesion peptide Arg-Gly-Asp-Ser increased endothelial adhesion to a level equivalent to tissue culture polystyrene. These biodegradable PEEUUs thus possessed properties that would be amenable to applications where high strength and flexibility would be desirable and exhibited the potential for tuning with appropriate triblock segment selection and surface modification. PMID:14580912

  8. Critical evaluation of biodegradable polymers used in nanodrugs

    PubMed Central

    Marin, Edgar; Briceño, Maria Isabel; Caballero-George, Catherina

    2013-01-01

    Use of biodegradable polymers for biomedical applications has increased in recent decades due to their biocompatibility, biodegradability, flexibility, and minimal side effects. Applications of these materials include creation of skin, blood vessels, cartilage scaffolds, and nanosystems for drug delivery. These biodegradable polymeric nanoparticles enhance properties such as bioavailability and stability, and provide controlled release of bioactive compounds. This review evaluates the classification, synthesis, degradation mechanisms, and biological applications of the biodegradable polymers currently being studied as drug delivery carriers. In addition, the use of nanosystems to solve current drug delivery problems are reviewed. PMID:23990720

  9. Critical evaluation of biodegradable polymers used in nanodrugs.

    PubMed

    Marin, Edgar; Briceño, Maria Isabel; Caballero-George, Catherina

    2013-01-01

    Use of biodegradable polymers for biomedical applications has increased in recent decades due to their biocompatibility, biodegradability, flexibility, and minimal side effects. Applications of these materials include creation of skin, blood vessels, cartilage scaffolds, and nanosystems for drug delivery. These biodegradable polymeric nanoparticles enhance properties such as bioavailability and stability, and provide controlled release of bioactive compounds. This review evaluates the classification, synthesis, degradation mechanisms, and biological applications of the biodegradable polymers currently being studied as drug delivery carriers. In addition, the use of nanosystems to solve current drug delivery problems are reviewed. PMID:23990720

  10. BIODEGRADATION PROBABILITY PROGRAM (BIODEG)

    EPA Science Inventory

    The Biodegradation Probability Program (BIODEG) calculates the probability that a chemical under aerobic conditions with mixed cultures of microorganisms will biodegrade rapidly or slowly. It uses fragment constants developed using multiple linear and non-linear regressions and d...

  11. Biodegradable synthetic bone composites

    DOEpatents

    Liu, Gao; Zhao, Dacheng; Saiz, Eduardo; Tomsia, Antoni P.

    2013-01-01

    The invention provides for a biodegradable synthetic bone composition comprising a biodegradable hydrogel polymer scaffold comprising a plurality of hydrolytically unstable linkages, and an inorganic component; such as a biodegradable poly(hydroxyethylmethacrylate)/hydroxyapatite (pHEMA/HA) hydrogel composite possessing mineral content approximately that of human bone.

  12. Characterization of biodegraded coals

    SciTech Connect

    Bean, R.M.; Franz, J.A.; Campbell, J.C.; Linehan, J.C.; Stewart, D.L.; Thomas, B.L.

    1988-04-01

    We have been able to accomplish the biodegradation of bituminous Illinois No. 6 coal after a pretreatment consisting of air oxidation, using a culture of the fungus Penicillium sp. We report in this paper results of chemical and spectrometric analyses of the starting materials and products from Illinois No. 6 coal biodegradation, and compare the results with those previously reported from the biodegradation of leonardite. 13 refs., 1 fig., 5 tabs.

  13. Biodegradability of Plastics

    PubMed Central

    Tokiwa, Yutaka; Calabia, Buenaventurada P.; Ugwu, Charles U.; Aiba, Seiichi

    2009-01-01

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed. PMID:19865515

  14. Biodegradable Photonic Melanoidin for Theranostic Applications.

    PubMed

    Lee, Min-Young; Lee, Changho; Jung, Ho Sang; Jeon, Mansik; Kim, Ki Su; Yun, Seok Hyun; Kim, Chulhong; Hahn, Sei Kwang

    2016-01-26

    Light-absorbing nanoparticles for localized heat generation in tissues have various biomedical applications in diagnostic imaging, surgery, and therapies. Although numerous plasmonic and carbon-based nanoparticles with strong optical absorption have been developed, their clearance, potential cytotoxicity, and long-term safety issues remain unresolved. Here, we show that "generally regarded as safe (GRAS)" melanoidins prepared from glucose and amino acid offer a high light-to-heat conversion efficiency, biocompatibility, biodegradability, nonmutagenicity, and efficient renal clearance, as well as a low cost for synthesis. We exhibit a wide range of biomedical photonic applications of melanoidins, including in vivo photoacoustic mapping of sentinel lymph nodes, photoacoustic tracking of gastrointestinal tracts, photothermal cancer therapy, and photothermal lipolysis. The biodegradation rate and renal clearance of melanoidins are controllable by design. Our results confirm the feasibility of biodegradable melanoidins for various photonic applications to theranostic nanomedicines. PMID:26623481

  15. Grey water biodegradability.

    PubMed

    Ghunmi, Lina Abu; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

    2011-02-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different conditions in the biodegradation test. The maximum aerobic and anaerobic biodegradability and conversion rate for the different COD fractions is determined. The results show that, on average, dormitory grey water COD fractions are 28% suspended, 32% colloidal and 40% dissolved. The studied factors incubation time, inoculum addition and temperature are influencing the determined biodegradability. The maximum biodegradability and biodegradation rate differ between different COD fractions, viz. COD(ss), COD(col) and COD(diss). The dissolved COD fraction is characterised by the lowest degradation rate, both for anaerobic and aerobic conditions. The maximum biodegradability for aerobic and anaerobic conditions is 86 and 70% respectively, whereas the first order conversion rate constant, k₂₀, is 0.119 and 0.005 day⁻¹, respectively. The anaerobic and aerobic conversion rates in relation to temperature can be described by the Arrhenius relation, with temperature coefficients of 1.069 and 1.099, respectively. PMID:20658309

  16. Synthesis, characterization, and paclitaxel release from a biodegradable, elastomeric, poly(ester urethane)urea bearing phosphorylcholine groups for reduced thrombogenicity.

    PubMed

    Hong, Yi; Ye, Sang-Ho; Pelinescu, Anca L; Wagner, William R

    2012-11-12

    Biodegradable polymers with high elasticity, low thrombogenicity, and drug loading capacity continue to be pursued for vascular engineering applications, including vascular grafts and stents. A biodegradable elastomeric polyurethane was designed as a candidate material for use as a drug-eluting stent coating, such that it was nonthrombogenic and could provide antiproliferative drug release to inhibit smooth muscle cell proliferation. A phosphorylcholine containing poly(ester urethane) urea (PEUU-PC) was synthesized by grafting aminated phosphorylcholine onto backbone carboxyl groups of a polyurethane (PEUU-COOH) synthesized from a soft segment blend of polycaprolactone and dimethylolpropionic acid, a hard segment of diisocyanatobutane and a putrescine chain extender. Poly(ester urethane) urea (PEUU) from a soft segment of polycaprolactone alone was employed as a control material. All of the synthesized polyurethanes showed high distensibility (>600%) and tensile strengths in the 20-35 MPa range. PEUU-PC experienced greater degradation than PEUU or PEUU-COOH in either a saline or lipase enzyme solution. PEUU-PC also exhibited markedly inhibited ovine blood platelet deposition compared with PEUU-COOH and PEUU. Paclitaxel loaded in all of the polymers during solvent casting continued to release for 5 d after a burst release in a 10% ethanol/PBS solution, which was utilized to increase the solubility of the releasate. Rat smooth muscle cell proliferation was significantly inhibited in 1 wk cell culture when releasate from the paclitaxel-loaded films was present. Based on these results, the synthesized PEUU-PC has promising functionality for use as a nonthrombogenic, drug eluting coating on metallic vascular stents and grafts. PMID:23035885

  17. Synthesis, Characterization, and Paclitaxel Release from a Biodegradable, Elastomeric, Poly(ester urethane)urea Bearing Phosphorylcholine Groups for Reduced Thrombogenicity

    PubMed Central

    Hong, Yi; Ye, Sang-Ho; Pelinescu, Anca L.; Wagner, William R.

    2013-01-01

    Biodegradable polymers with high elasticity, low thrombogenicity, and drug loading capacity continue to be pursued for vascular engineering applications, including vascular grafts and stents. A biodegradable elastomeric polyurethane was designed as a candidate material for use as a drug-eluting stent coating, such that it was nonthrombogenic and could provide antiproliferative drug release to inhibit smooth muscle cell proliferation. A phosphorylcholine containing poly(ester urethane) urea (PEUU-PC) was synthesized by grafting aminated phosphorylcholine onto backbone carboxyl groups of a polyurethane (PEUU-COOH) synthesized from a soft segment blend of polycaprolactone and dimethylolpropionic acid, a hard segment of diisocyanatobutane and a putrescine chain extender. Poly(ester urethane) urea (PEUU) from a soft segment of polycaprolactone alone was employed as a control material. All of the synthesized polyurethanes showed high distensibility (>600%) and tensile strengths in the 20–35 MPa range. PEUUPC experienced greater degradation than PEUU or PEUU-COOH in either a saline or lipase enzyme solution. PEUU-PC also exhibited markedly inhibited ovine blood platelet deposition compared with PEUU-COOH and PEUU. Paclitaxel loaded in all of the polymers during solvent casting continued to release for 5 d after a burst release in a 10% ethanol/PBS solution, which was utilized to increase the solubility of the releasate. Rat smooth muscle cell proliferation was significantly inhibited in 1 wk cell culture when releasate from the paclitaxel-loaded films was present. Based on these results, the synthesized PEUU-PC has promising functionality for use as a nonthrombogenic, drug eluting coating on metallic vascular stents and grafts. PMID:23035885

  18. Characterization of biodegraded coals

    SciTech Connect

    Bean, R.M.; Franz, J.A.; Campbell, J.A.; Linehan, J.C.; Stewart, D.L.; Thomas, B.L.

    1988-01-01

    Microbial degradation of coals to materials that are soluble in water has been a topic of intensive research for the last few years. The potential for economical recovery of low-grade coals, coupled with possibilities for further upgrading by microbial desulfurization or methanation has spurred intensive research at a number of laboratories. Until very recently, coal biodegradation has been accomplished using low-grade, naturally oxidized coals such as leonardiate, or coals subjected to pretreatment with oxidizing chemicals. The authors have been able to accomplish the biodegradation of bituminous Illinois 6 coal after a pretreatment consisting of air oxidation, using a culture of the fungus Penicillium sp. They report in this paper results of chemical and spectrometric analyses of the starting materials and products from Illinois 6 coal biodegradation, and compare the results with those previously reported from the biodegradation of leonardite.

  19. Synthesis and characterization of biodegradable poly(ethylene glycol)-block-poly(5-benzyloxy-trimethylene carbonate) copolymers for drug delivery.

    PubMed

    Zeng, Faquan; Liu, Jubo; Allen, Christine

    2004-01-01

    Amphiphilic diblock copolymers with various block compositions were synthesized with monomethoxy-terminated poly(ethylene glycol) (MePEG) as the hydrophilic block and poly(5-benzyloxy-trimethylene carbonate) (PBTMC) as the hydrophobic block. When the copolymerization was conducted using MePEG as a macroinitiator and stannous 2-ethylhexanoate (Sn(Oct)2) as a catalyst, the molecular weight of the second block was uncontrollable, and the method only afforded a mixture of homopolymer and copolymer with a broad molecular weight distribution. By contrast, the use of the triethylaluminum-MePEG initiator yielded block copolymers with controllable molecular weight and a more narrow molecular weight distribution than the copolymers obtained using Sn(Oct)2. GPC and 1H NMR studies confirmed that the macroinitiator was consumed and the copolymer composition was as predicted. Two of the newly synthesized MePEG-b-PBTMC copolymers were evaluated in terms of properties primarily relating to their use in micellar drug delivery. MePEG-b-PBTMC micelles with a narrow monomodal size distribution were prepared using a high-pressure extrusion technique. The MePEG-b-PBTMC copolymers were also confirmed to be biodegradable and noncytotoxic. PMID:15360292

  20. Bacterial production of the biodegradable plastics polyhydroxyalkanoates.

    PubMed

    Urtuvia, Viviana; Villegas, Pamela; González, Myriam; Seeger, Michael

    2014-09-01

    Petroleum-based plastics constitute a major environmental problem due to their low biodegradability and accumulation in various environments. Therefore, searching for novel biodegradable plastics is of increasing interest. Microbial polyesters known as polyhydroxyalkanoates (PHAs) are biodegradable plastics. Life cycle assessment indicates that PHB is more beneficial than petroleum-based plastics. In this report, bacterial production of PHAs and their industrial applications are reviewed and the synthesis of PHAs in Burkholderia xenovorans LB400 is described. PHAs are synthesized by a large number of microorganisms during unbalanced nutritional conditions. These polymers are accumulated as carbon and energy reserve in discrete granules in the bacterial cytoplasm. 3-hydroxybutyrate and 3-hydroxyvalerate are two main PHA units among 150 monomers that have been reported. B. xenovorans LB400 is a model bacterium for the degradation of polychlorobiphenyls and a wide range of aromatic compounds. A bioinformatic analysis of LB400 genome indicated the presence of pha genes encoding enzymes of pathways for PHA synthesis. This study showed that B. xenovorans LB400 synthesize PHAs under nutrient limitation. Staining with Sudan Black B indicated the production of PHAs by B. xenovorans LB400 colonies. The PHAs produced were characterized by GC-MS. Diverse substrates for the production of PHAs in strain LB400 were analyzed. PMID:24974981

  1. Synthesis of novel biodegradable and self-assembling methoxy poly(ethylene glycol)-palmitate nanocarrier for curcumin delivery to cancer cells.

    PubMed

    Sahu, Abhishek; Bora, Utpal; Kasoju, Naresh; Goswami, Pranab

    2008-11-01

    A novel polymeric amphiphile, mPEG-PA, was synthesized with methoxy poly(ethylene glycol) (mPEG) as the hydrophilic and palmitic acid (PA) as the hydrophobic segment. The conjugate prepared in a single-step reaction showed minimal toxicity on HeLa cells. (1)H nuclear magnetic resonance imaging and Fourier transform infrared spectroscopy revealed that the conjugation was through an ester linkage, which is biodegradable. Enzymes having esterase activity, such as lipase, can degrade the conjugate easily, as observed by in vitro studies. mPEG-PA conjugate undergoes self-assembly in an aqueous environment, as evidenced by fluorescence spectroscopic studies with pyrene as a probe. The mPEG-PA conjugate formed micelles in the aqueous solution with critical micelle concentration of 0.12 g l(-1). Atomic force microscopy and dynamic light scattering studies showed that the micelles were spherical in shape, with a mean diameter of 41.43 nm. The utility of mPEG-PA to entrap the potent chemopreventive agent curcumin in the core of nanocarrier was investigated. The encapsulation of a highly hydrophobic compound like curcumin in the nanocarrier makes the drug readily soluble in an aqueous system, which can increase the ease of dosing and makes intravenous dosing possible. Drug-loaded micelle nanoparticles showed good stability in physiological condition (pH 7.4), in simulated gastric fluid (pH 1.2) and in simulated intestinal fluid (pH 6.8). This micellar formulation can be used as an enzyme-triggered drug release carrier, as suggested by in vitro enzyme-catalyzed drug release using pure lipase and HeLa cell lysate. The IC(50) of free curcumin and encapsulated curcumin was found to be 14.32 and 15.58 microM, respectively. PMID:18524701

  2. Synthesis, characterization and biocompatibility of novel biodegradable cross-linked co-polymers based on poly(propylene oxide) diglycidylether and polyethylenimine.

    PubMed

    Ding, Yunsheng; Wang, Jing; Wong, Cynthia S; Halley, Peter J; Guo, Qipeng

    2011-01-01

    Novel biodegradable cross-linked co-polymers were prepared from poly(propylene glycol) diglycidylether (PPGDGE) and poly(ethylene imine) (PEI). PPGDGE and PEI were mixed at ambient temperature with varying PEI concentrations of 10, 15, 18.5, 25, 30, 40 and 50 wt%; the homogenous PPGDGE/PEI mixtures obtained were cured at elevated temperatures, resulting in formation of PPG-PEI cross-linked co-polymers via ring-opening reaction of PPGDGE with PEI. The physicochemical and biological properties of these co-polymers were dependent on the PEI content and the extent of curing reaction. The glass transition temperature of PPG-PEI cross-linked co-polymers varied in the range from -14 to +42°C, while the co-polymers displayed composition-dependent mechanical behavior, from brittle to ductile with increasing PEI content from 18.5 wt% to 40 wt%. Chinese hamster ovary (CHO) cells were cultured on the PPG-PEI co-polymers; the MTT assay was used to measure cell viability and determine the cytotoxicity. The cell viability rate, relative to tissue-culture polystyrene (TCPS), increased from 49% to 125% with increasing PEI content from 18.5 wt% to 40 wt%. Although epoxy monomers usually exhibit cytotoxicity, the epoxy groups were exhausted via curing reaction in the fully cross-linked co-polymers. The PEI-cured PPG epoxy resin, i.e., PPG-PEI cross-linked co-polymers obtained in this study, showed excellent biocompatibility. PMID:20566040

  3. Biodegradable Epoxy Networks Cured with Polypeptides

    NASA Astrophysics Data System (ADS)

    Nakamura, Shigeo; Kramer, Edward J.

    2006-03-01

    Epoxy resins are used widely for adhesives as well as coatings. However, once cured they are usually highly cross-linked and are not biodegradable. To obtain potentially biodegradable polypeptides that can cure with epoxy resins and achieve as good properties as the conventional phenol novolac hardeners, poly(succinimide-co-tyrosine) was synthesized by thermal polycondensation of L-aspartic acid and L-tyrosine with phosphoric acid under reduced pressure. The tyrosine/succinimide ratio in the polypeptide was always lower than the tyrosine/(aspartic acid) feed ratio and was influenced by the synthesis conditions. Poly(succinimide-tyrosine- phenylalanine) was also synthesized from L-aspartic acid, L- tyrosine and L-phenylalanine. The thermal and mechanical properties of epoxy resins cured with these polypeptides are comparable to those of similar resins cured with conventional hardeners. In addition, enzymatic degradability tests showed that Chymotrypsin or Subtilisin A could cleave cured films in an alkaline borate buffer.

  4. Biodegradable electroactive materials for tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Guimard, Nathalie Kathryn

    This dissertation focuses on the development of biomaterials that could be used to enhance the regeneration of severed peripheral nerves. These materials were designed to be electroactive, biodegradable, and biocompatible. To render the materials electroactive the author chose to incorporate conducting polymer (CP) units into the materials. Because CPs are inherently non-degradable, the key challenge was to create a CP-based material that was also biodegradable. Two strategies were explored to generate a biodegradable CP-based material. The first strategy centered around the incorporation of both electroactive and biodegradable subunits into a copolymer system. In the context of this approach, two bis(methoxyquaterthiophene)-co-adipic acid polyester (QAPE) analogues were successfully synthesized, one through polycondensation (giving undoped QAPE) and the second through oxidative polymerization (giving doped QAPE-2). QAPE was found to be electroactive by cyclic voltammetry, bioerodible, and cytocompatible with Schwann cells. QAPE was doped with ferric perchlorate, although only a low doping percentage was realized (˜8%). Oxidative polymerization of a bis(bithiophene) adipate permitted the direct synthesis of doped QAPE-2, which was found to have a higher doping level (˜24%). The second strategy pursued with the goal of generating an electroactive biodegradable material involved covalently immobilizing low molecular weight polythiophene chains onto the surface of crosslinked hyaluronic acid (HA) films. HA films are not only biodegradable and biocompatible, but they also provide mechanical integrity to bilayer systems. Dicyclocarbodiimide coupling of carboxylic acids to HA alcohol groups was used to functionalize HA films. The HA-polythiophene composite is still in the early stages of development. However, to date, thiophene has been successfully immobilized at the surface of HA films with a high degree of substitution. The author has also shown that thiophene

  5. Biodegradable Materials for Nonwovens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Demand for nonwovens is increasing globally, particularly in the disposable products area. As the consumption of nonwoven products with short life increases, the burden on waste disposal also rises. In this context, biodegradable nonwovens become more important today and for the future. Several new ...

  6. Safe biodegradable fluorescent particles

    DOEpatents

    Martin, Sue I.; Fergenson, David P.; Srivastava, Abneesh; Bogan, Michael J.; Riot, Vincent J.; Frank, Matthias

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  7. Biodegradable Polymers for the Environment

    NASA Astrophysics Data System (ADS)

    Gross, Richard A.; Kalra, Bhanu

    2002-08-01

    Biodegradable polymers are designed to degrade upon disposal by the action of living organisms. Extraordinary progress has been made in the development of practical processes and products from polymers such as starch, cellulose, and lactic acid. The need to create alternative biodegradable water-soluble polymers for down-the-drain products such as detergents and cosmetics has taken on increasing importance. Consumers have, however, thus far attached little or no added value to the property of biodegradability, forcing industry to compete head-to-head on a cost-performance basis with existing familiar products. In addition, no suitable infrastructure for the disposal of biodegradable materials exists as yet.

  8. Aerobic biodegradation of the brominated flame retardants, dibromoneopentyl glycol and tribromoneopentyl alcohol.

    PubMed

    Segev, Osnat; Meusel, Wolfram; Friedenberger, Melanie; Brenner, Asher; Kushmaro, Ariel

    2009-09-01

    Halogenated organic compounds constitute one of the largest and most diverse groups of chemicals in the environment. Many of these compounds are toxic, persistent and, as a result of their often limited biodegradability, tend to bioaccumulate in the environment. Dibromoneopentyl glycol (DBNPG) and tribromoneopentyl alcohol (TBNPA) are brominated flame retardants commonly used as additives during the manufacture of plastic polymers and as chemical intermediates in the synthesis of other flame retardants. Both are classified as not readily biodegradable. In this paper, we demonstrate the biodegradation of both DBNPG and TBNPA by a common bacterial consortium under aerobic conditions in enrichment cultures containing yeast extract. DBNPG and TBNPA biodegradation is accompanied by a release of bromide into the medium, due to a biological debromination reaction. Molecular analysis of the clone library PCR amplified 16S rRNA gene was used to characterize the bacterial consortium involved in the biodegradation. PMID:19205903

  9. Biodegradable pectin/clay aerogels.

    PubMed

    Chen, Hong-Bing; Chiou, Bor-Sen; Wang, Yu-Zhong; Schiraldi, David A

    2013-03-13

    Biodegradable, foamlike materials based on renewable pectin and sodium montmorillonite clay were fabricated through a simple, environmentally friendly freeze-drying process. The addition of multivalent cations (Ca(2+) and Al(3+)) resulted in apparent cross-linking of the polymer and enhancement of aerogel properties. The compressive properties increased as the solid contents (both pectin and clay) increased; moduli in the range of 0.04-114 MPa were obtained for materials with bulk densities ranging from 0.03 g/cm(3) to 0.19 g/cm(3), accompanied by microstructural changes from a lamellar structure to a cellular structure. Biodegradability of the aerogels was investigated by detecting CO2 release for 4 weeks in compost media. The results revealed that pectin aerogels possess higher biodegradation rates than wheat starch, which is often used as a standard for effective biodegradation. The addition of clay and multivalent cations surprisingly increased the biodegradation rates. PMID:23406325

  10. Marine Oil Biodegradation.

    PubMed

    Hazen, Terry C; Prince, Roger C; Mahmoudi, Nagissa

    2016-03-01

    Crude oil has been part of the marine environment for millions of years, and microbes that use its rich source of energy and carbon are found in seawater, sediments, and shorelines from the tropics to the polar regions. Catastrophic oil spills stimulate these organisms to "bloom" in a reproducible fashion, and although oil does not provide bioavailable nitrogen, phosphorus or iron, there are enough of these nutrients in the sea that when dispersed oil droplets dilute to low concentrations these low levels are adequate for microbial growth. Most of the hydrocarbons in dispersed oil are degraded in aerobic marine waters with a half-life of days to months. In contrast, oil that reaches shorelines is likely to be too concentrated, have lower levels of nutrients, and have a far longer residence time in the environment. Oil that becomes entrained in anaerobic sediments is also likely to have a long residence time, although it too will eventually be biodegraded. Thus, data that encompass everything from the ecosystem to the molecular level are needed for understanding the complicated process of petroleum biodegradation in marine environments. PMID:26698270

  11. Preparation of a biodegradable oil absorber and its biodegradation.

    PubMed

    Yoo, Su-Yong; Daud, Wan Mohd Ashri Wan; Lee, Min-Gyu

    2012-01-01

    The biodegradable oil absorption resin (B-PEHA) was prepared by suspension polymerization, and its preparation was confirmed by Fourier transform infrared analysis. The oil absorption capacities of the prepared B-PEHA were: chloroform 30.88, toluene 19.75, xylene, 18.78, THF 15.96, octane 11.43, hexane 9.5, diesel oil 12.80, and kerosene 13.79 g/g. The biodegradation of the prepared B-PEHA was also investigated by determination of reduced sugar produced after enzymatic hydrolysis, thermogravimetric analysis, and incubation with Aspergillus niger. The biodegradation of B-PEHA was ~18%. PMID:21909668

  12. Biodegradation of Polypropylene Nonwovens

    NASA Astrophysics Data System (ADS)

    Keene, Brandi Nechelle

    The primary aim of the current research is to document the biodegradation of polypropylene nonwovens and filament under composting environments. To accelerate the biodegradat ion, pre-treatments and additives were incorporated into polypropylene filaments and nonwovens. The initial phase (Chapter 2) of the project studied the biodegradation of untreated polypropylene with/without pro-oxidants in two types of composting systems. Normal composting, which involved incubation of samples in food waste, had little effect on the mechanical properties of additive-free spunbond nonwovens in to comparison prooxidant containing spunbond nonwovens which were affected significantly. Modified composting which includes the burial of samples with food and compressed air, the polypropylene spunbond nonwovens with/without pro-oxidants displayed an extreme loss in mechanical properties and cracking on the surface cracking. Because the untreated spunbond nonwovens did not completely decompose, the next phase of the project examined the pre-treatment of gamma-irradiation or thermal aging prior to composting. After exposure to gamma-irradiation and thermal aging, polypropylene is subjected to oxidative degradation in the presence of air and during storage after irradiat ion. Similar to photo-oxidation, the mechanism of gamma radiation and thermal oxidative degradation is fundamentally free radical in nature. In Chapter 3, the compostability of thermal aged spunbond polypropylene nonwovens with/without pro-oxidant additives. The FTIR spectrum confirmed oxidat ion of the polypropylene nonwovens with/without additives. Cracking on both the pro-oxidant and control spunbond nonwovens was showed by SEM imaging. Spunbond polypropylene nonwovens with/without pro-oxidants were also preirradiated by gamma rays followed by composting. Nonwovens with/without pro-oxidants were severely degraded by gamma-irradiation after up to 20 kGy exposure as explained in Chapter 4. Furthermore (Chapter 5), gamma

  13. The peroxidase-mediated biodegradation of petroleum hydrocarbons in a H2O2-induced SBR using in-situ production of peroxidase: Biodegradation experiments and bacterial identification.

    PubMed

    Shekoohiyan, Sakine; Moussavi, Gholamreza; Naddafi, Kazem

    2016-08-01

    A bacterial peroxidase-mediated oxidizing process was developed for biodegrading total petroleum hydrocarbons (TPH) in a sequencing batch reactor (SBR). Almost complete biodegradation (>99%) of high TPH concentrations (4g/L) was attained in the bioreactor with a low amount (0.6mM) of H2O2 at a reaction time of 22h. A specific TPH biodegradation rate as high as 44.3mgTPH/gbiomass×h was obtained with this process. The reaction times required for complete biodegradation of TPH concentrations of 1, 2, 3, and 4g/L were 21, 22, 28, and 30h, respectively. The catalytic activity of hydrocarbon catalyzing peroxidase was determined to be 1.48U/mL biomass. The biodegradation of TPH in seawater was similar to that in fresh media (no salt). A mixture of bacteria capable of peroxidase synthesis and hydrocarbon biodegradation including Pseudomonas spp. and Bacillus spp. were identified in the bioreactor. The GC/MS analysis of the effluent indicated that all classes of hydrocarbons could be well-degraded in the H2O2-induced SBR. Accordingly, the peroxidase-mediated process is a promising method for efficiently biodegrading concentrated TPH-laden saline wastewater. PMID:27060866

  14. Biodegradation of PCBs

    SciTech Connect

    Kopec, R.I.

    1992-01-01

    PCBs were examined for biodegradability by a strain of Pseudomonas sp. designated E1, by a strain of Pseudomonas aeruginosa designated E2, and by a strain of Pseudomonas putida designated E3. The PCBs included Aroclor mixes from Aroclor 1221 to Aroclor 1268, and pure congeners ranging from monochlorobiphenyl to decachlorobiphenyl. These congeners represented all structural classes. Pure culture studies revealed that cells of E1 grew well on all structural classes of PCB congeners up to heptachlorobiphenyl, and all Aroclor mixes up to Aroclor 1260. Gas chromotographic analysis revealed that biphenyl/acetate grown resting cells of E1 degraded congeners up to octachlorobiphenyl. The degradative patterns for E2 and E3 were assessed using gas chromatographic techniques. E2 was found to be markedly inferior to E1, degrading only the mono-, di-, and tri-chlorobiphenyl tested. Pseudomonas putida strain E3 could not degrade any PCB congener. Mutations in both E2 and E3 that enabled them to utilize more highly chlorinated congeners of PCBs were obtained in nutritionally depleted environments. Such mutants could not be obtained by direct selection using minimal media and appear to be [open quotes]Cairnsian[close quotes] mutations. The Pseudomonas sp. strain E1 was tested in 15 prior or current National Priority List soil microcosms to assess its biodegradative ability in situ. E1 was able to completely degrade the 2,3,4,2[prime],3[prime],4[prime]-2,4,5,2[prime],4[prime],5[prime]-hexachlorobiphenyl congener in seven of the microcosms within two months as well.

  15. Biodegradation of biodiesel fuels

    SciTech Connect

    Zhang, X.; Haws, R.; Wright, B.; Reese, D.; Moeller, G.; Peterson, C.

    1995-12-31

    Biodiesel fuel test substances Rape Ethyl Ester (REE), Rape Methyl Ester (RME), Neat Rape Oil (NR), Say Methyl Ester (SME), Soy Ethyl Ester (SEE), Neat Soy Oil (NS), and proportionate combinations of RME/diesel and REE/diesel were studied to test the biodegradability of the test substances in an aerobic aquatic environment using the EPA 560/6-82-003 Shake Flask Test Method. A concurrent analysis of Phillips D-2 Reference Diesel was also performed for comparison with a conventional fuel. The highest rates of percent CO{sub 2} evolution were seen in the esterified fuels, although no significant difference was noted between them. Ranges of percent CO{sub 2} evolution for esterified fuels were from 77% to 91%. The neat rape and neat soy oils exhibited 70% to 78% CO{sub 2} evolution. These rates were all significantly higher than those of the Phillips D-2 reference fuel which evolved from 7% to 26% of the organic carbon to CO{sub 2}. The test substances were examined for BOD{sub 5} and COD values as a relative measure of biodegradability. Water Accommodated Fraction (WAF) was experimentally derived and BOD{sub 5} and COD analyses were carried out with a diluted concentration at or below the WAF. The results of analysis at WAF were then converted to pure substance values. The pure substance BOD{sub 5} and COD values for test substances were then compared to a control substance, Phillips D-2 Reference fuel. No significant difference was noted for COD values between test substances and the control fuel. (p > 0.20). The D-2 control substance was significantly lower than all test substances for BCD, values at p << 0.01. RME was also significantly lower than REE (p < 0.05) and MS (p < 0.01) for BOD{sub 5} value.

  16. FOSSIL FUEL BIODEGRADATION: LABORATORY STUDIES

    EPA Science Inventory

    Natural processes of biodegradation, that return carbon from its various organic forms to the inorganic state, are increasingly screened for bioremediation applications. ariety of microbial systems capable of degrading synthetic organic chemicals, from pesticides to polychlorinat...

  17. Phenanthrene Biodegradation in Freshwater Environments

    PubMed Central

    Sherrill, T. W.; Sayler, G. S.

    1980-01-01

    Phenanthrene, a low-molecular-weight polycyclic aromatic hydrocarbon, was incubated with water samples from various reservoir systems in Tennessee to evaluate the potential for significant polycyclic aromatic hydrocarbon degradation by the indigenous microbial populations. Biodegradation was assessed by comparison of total polycyclic aromatic hydrocarbon substrate recovery in degradation flasks relative to sterile control flasks. During 1977 field studies, the mean phenanthrene biodegradation was approximately 80% after a 4-week incubation. Within a given habitat, 45% of the total variability in phenanthrene biodegradation was attributable to the physical, chemical, and microbiological site characteristics examined. Polycyclic aromatic hydrocarbon degradation was directly related to the historical environmental pollution of the sampling sites examined, the length of biodegradation assessment, temperature, and the molecular size of the polycyclic aromatic hydrocarbon substrate. PMID:16345487

  18. THERMOPHILIC ANAEROBIC BIODEGRADATION OF PHENOLICS

    EPA Science Inventory

    The report gives results of a series of anaerobic microbial acclimation and treatment performance tests with synthetic phenolic substrates. The research is a feasibility level assessment of substituting anaerobic biodegradation of phenolics for solvent extraction. The tests showe...

  19. Biodegradable polyoxalate and copolyoxalate particles for drug-delivery applications.

    PubMed

    Hong, Donghyun; Song, Byungjoo; Kim, Hyungmin; Kwon, Jungil; Khang, Gilson; Lee, Dongwon

    2011-11-01

    Polyoxalate and copolyoxalate were developed in the 1970s and have been used for biomedical applications such as suture coating purposes, owing to their biocompatibility and biodegradability. They are known to degrade into diols and oxalic acid, which are considered biocompatible. One of the advantages of oxalate-based polymer is the ease of control of physicochemical properties, such as biodegradability, crystallinity and mechanical strength. The composition and hydrophobicity of diols greatly influenced their hydrolytic stability and mechanical properties. Oxalate-based polymers have faster hydrolytic-degradation kinetics than the commercial biodegradable polymers, poly(lactide-co-glycolide) and poly(caprolactone). Recently, our group has developed fully biodegradable polymer drug carriers based on oxalate-based polymers that are composed of various diols. The hydrophobicity of the oxalate-based polymers allowed them to be formulated into nano- or micro-particles, which are suitable for targeting macrophages in inflammatory diseases. The nano- or micro-particles exhibited excellent cytotoxicity profiles and fast drug-release kinetics, suggesting great potential as drug-delivery systems for the treatment of acute inflammatory diseases. In this article, we discuss the synthesis and physicochemical properties of oxalate-based polymers which can be used as a drug-delivery vehicle for the treatment of inflammatory diseases. PMID:22826873

  20. Biodegradation of polyethoxylated nonylphenols.

    PubMed

    Ruiz, Yassellis; Medina, Luis; Borusiak, Margarita; Ramos, Nairalith; Pinto, Gilberto; Valbuena, Oscar

    2013-01-01

    Polyethoxylated nonylphenols, with different ethoxylation degrees (NPEO x ), are incorporated into many commercial and industrial products such as detergents, domestic disinfectants, emulsifiers, cosmetics, and pesticides. However, the toxic effects exerted by their degradation products, which are persistent in natural environments, have been demonstrated in several animal and invertebrate aquatic species. Therefore, it seems appropriate to look for indigenous bacteria capable of degrading native NPEO x and its derivatives. In this paper, the isolation of five bacterial strains, capable of using NPEO 15 , as unique carbon source, is described. The most efficient NPEO 15 degrader bacterial strains were identified as Pseudomonas fluorescens (strain Yas2) and Klebsiella pneumoniae (strain Yas1). Maximal growth rates were reached at pH 8, 27°C in a 5% NPEO 15 medium. The NPEO 15 degradation extension, followed by viscometry assays, reached 65% after 54.5 h and 134 h incubation times, while the COD values decreased by 95% and 85% after 24 h for the Yas1 and Yas2 systems, respectively. The BOD was reduced by 99% and 99.9% levels in 24 h and 48 h incubations. The viscosity data indicated that the NPEO 15 biodegradation by Yas2 follows first-order kinetics. Kinetic rate constant (k) and half life time (τ) for this biotransformation were estimated to be 0.0072 h(-1) and 96.3 h, respectively. PMID:23936727

  1. Biodegradation of radioactive animals

    SciTech Connect

    Party, N.; Party, E.; Wilkerson, A.

    1995-06-01

    The two most common disposal alternatives for animals contaminated with radioactive materials are incineration and burial. For most of the country burial has entailed shipping the carcasses to a commercial disposal facility at Barnwell, South Carolina, where it was landfilled along with other solid radioactive waste. Unfortunately, since 30 June 1994, this facility accepts waste generated by the states of the Southeast Compact only. Therefore, burial is no longer an option for most of the country`s generators and incineration is an option only for those institutions which have, or have access to, an incinerator that is permitted to burn radioactive materials and that accepts animal carcasses with de minimis levels of radioactive contaminants. Many institutions, especially those in congested urban areas where the public does not support incineration, do not have viable outlets for radioactive animal carcasses. Interim, on-site storage poses problems of its own. Biodegradation of animal carcasses with dermestid beetles is an inexpensive approach to this waste management problem. 7 refs., 3 figs., 1 tab.

  2. Biodegradation of Polyethoxylated Nonylphenols

    PubMed Central

    Ruiz, Yassellis; Medina, Luis; Borusiak, Margarita; Ramos, Nairalith; Pinto, Gilberto; Valbuena, Oscar

    2013-01-01

    Polyethoxylated nonylphenols, with different ethoxylation degrees (NPEOx), are incorporated into many commercial and industrial products such as detergents, domestic disinfectants, emulsifiers, cosmetics, and pesticides. However, the toxic effects exerted by their degradation products, which are persistent in natural environments, have been demonstrated in several animal and invertebrate aquatic species. Therefore, it seems appropriate to look for indigenous bacteria capable of degrading native NPEOx and its derivatives. In this paper, the isolation of five bacterial strains, capable of using NPEO15, as unique carbon source, is described. The most efficient NPEO15 degrader bacterial strains were identified as Pseudomonas fluorescens (strain Yas2) and Klebsiella pneumoniae (strain Yas1). Maximal growth rates were reached at pH 8, 27°C in a 5% NPEO15 medium. The NPEO15 degradation extension, followed by viscometry assays, reached 65% after 54.5 h and 134 h incubation times, while the COD values decreased by 95% and 85% after 24 h for the Yas1 and Yas2 systems, respectively. The BOD was reduced by 99% and 99.9% levels in 24 h and 48 h incubations. The viscosity data indicated that the NPEO15 biodegradation by Yas2 follows first-order kinetics. Kinetic rate constant (k) and half life time (τ) for this biotransformation were estimated to be 0.0072 h−1 and 96.3 h, respectively. PMID:23936727

  3. Injectable and biodegradable hydrogels: gelation, biodegradation and biomedical applications.

    PubMed

    Li, Yulin; Rodrigues, João; Tomás, Helena

    2012-03-21

    Injectable hydrogels with biodegradability have in situ formability which in vitro/in vivo allows an effective and homogeneous encapsulation of drugs/cells, and convenient in vivo surgical operation in a minimally invasive way, causing smaller scar size and less pain for patients. Therefore, they have found a variety of biomedical applications, such as drug delivery, cell encapsulation, and tissue engineering. This critical review systematically summarizes the recent progresses on biodegradable and injectable hydrogels fabricated from natural polymers (chitosan, hyaluronic acid, alginates, gelatin, heparin, chondroitin sulfate, etc.) and biodegradable synthetic polymers (polypeptides, polyesters, polyphosphazenes, etc.). The review includes the novel naturally based hydrogels with high potential for biomedical applications developed in the past five years which integrate the excellent biocompatibility of natural polymers/synthetic polypeptides with structural controllability via chemical modification. The gelation and biodegradation which are two key factors to affect the cell fate or drug delivery are highlighted. A brief outlook on the future of injectable and biodegradable hydrogels is also presented (326 references). PMID:22116474

  4. Effects of the Biodegradation on Biodegradable Polymer Blends and Polypropylene

    NASA Astrophysics Data System (ADS)

    Pereira, R. C. T.; Franchetti, S. M. M.; Agnelli, J. A. M.; Mattoso, L. H. C.

    2008-08-01

    The large use of plastics in the world generates a large amount of waste which persists around 200 years in the environment. To minimize this effect is important to search some new polymer materials: the blends of biodegradable polymers with synthetic polymers. It is a large area that needs an intensive research to investigate the blends properties and its behavior face to the different treatments to aim at the biodegradation. The blends used in this work are: some biodegradable polymers such as: poly(hydroxybutyrate) (PHB) and poly(ɛ-polycaprolactone) (PCL) with a synthetic polymer, polypropylene (PP), in lower concentration. These blends were prepared using an internal mixer (Torque Rheometer), and pressed. These films were submitted to fungus biotreatment. The films analyses will be carried out by Fourier Transform Infrared (FTIR), UV-Vis absorption (UV-Vis), Scanning Electronic Microscopy (SEM), DSC and TGA.

  5. Biodegradation of news inks

    SciTech Connect

    Erhan, S.Z.; Bagby, M.O.

    1995-12-01

    Printing ink vehicles that require no petroleum components were prepared by modifying vegetable oil. Physical properties of inks formulated with these vehicles meet or exceed the industry standards for lithographic and letterpress newsprint applications. Elimination of petroleum-based resin and reduced pigment requirements, due to the light vehicle color, provide a competitively priced alternative to petroleum-based inks of equal quality. These ink vehicles, made exclusively from soybean oil, were subjected to biodegradation, and the results were compared with those obtained with commercial vehicles. Results show that they degrade faster and more completely than commercial hybrid (partial) soy or mineral oil based vehicles. Fermentations were allowed to proceed for 5, 12, and 25 days. Both mono-and mixed cultures of microorganisms commonly found in soil were used. In 25 days, commercial mineral oil based vehicles degraded 17-27%, while commercial hybrid soy oil based vehicles degraded 58-68% and our 100% soy oil based vehicles degrade 82-92%. Similar studies were conducted with commercial news inks consisting of soy or mineral oil with petroleum resins along with the four colored pigments and USDA`s 100% soy oil based ink consisting of modified soybean oil and pigment. Results show that pigment slowed the degradation of ink vehicles; however, neither time nor type of pigment played a significant role. Also these inks were degraded by using {open_quotes}Modified Sturm Test{close_quotes} (Organization for Economic Cooperation and Development). In this method, test organisms were obtained from activated sludge, and the extent of degradation was determined by measuring carbon dioxide evolution. In all cases USDA`s ink degraded faster and more completely (for all four colors) than either hybrid soy oil based or petroleum based inks.

  6. Studies on the biodegradation of fosfomycin: synthesis of 13C-labeled intermediates, feeding experiments with Rhizobium huakuii PMY1, and isolation of labeled amino acids from cell mass by HPLC.

    PubMed

    McGrath, John W; Hammerschmidt, Friedrich; Kählig, Hanspeter; Wuggenig, Frank; Lamprecht, Günther; Quinn, John P

    2011-11-18

    Racemic (1R*,2R*)-1,2-dihydroxy-[1-(13)C(1)]propylphosphonic acid and 1-hydroxy-[1-(13)C(1)]acetone were synthesized and fed to R. huakuii PMY1. Alanine and a mixture of valine and methionine were isolated as their N-acetyl derivatives from the cell hydrolysate by reversed-phase HPLC and analyzed by NMR spectroscopy. It was found that the carbon atoms of the respective carboxyl groups were highly (13)C-labeled (up to 65 %). Hydroxyacetone is therefore considered an obligatory intermediate of the biodegradation of fosfomycin by R. huakuii PMY1. PMID:22012897

  7. Developments in metallic biodegradable stents.

    PubMed

    Hermawan, H; Dubé, D; Mantovani, D

    2010-05-01

    Interest in metallic degradable biomaterials research has been growing in the last decade. Both scientific journals and patent databases record a high increase in publications in this area. Biomedical implants with temporary function, such as coronary stents, are the targeted applications for this novel class of biomaterials. It is expected that stents made of degradable biomaterials, named biodegradable stents, will provide a temporary opening into a narrowed arterial vessel until the vessel remodels and will progressively disappear thereafter. Biodegradable stents made of metal have recently been progressed into preclinical tests in humans after their first introduction in early 2000s. By referring to patents and journal publications, this paper reviews the developments in biodegradable stents, with emphasis on those made of metals, starting from the first design ideas to validation testing. PMID:19815097

  8. Petroleum biodegradation in marine environments.

    PubMed

    Harayama, S; Kishira, H; Kasai, Y; Shutsubo, K

    1999-08-01

    Petroleum-based products are the major source of energy for industry and daily life. Petroleum is also the raw material for many chemical products such as plastics, paints, and cosmetics. The transport of petroleum across the world is frequent, and the amounts of petroleum stocks in developed countries are enormous. Consequently, the potential for oil spills is significant, and research on the fate of petroleum in a marine environment is important to evaluate the environmental threat of oil spills, and to develop biotechnology to cope with them. Crude oil is constituted from thousands of components which are separated into saturates, aromatics, resins and asphaltenes. Upon discharge into the sea, crude oil is subjected to weathering, the process caused by the combined effects of physical, chemical and biological modification. Saturates, especially those of smaller molecular weight, are readily biodegraded in marine environments. Aromatics with one, two or three aromatic rings are also efficiently biodegraded; however, those with four or more aromatic ring are quite resistant to biodegradation. The asphaltene and resin fractions contain higher molecular weight compounds whose chemical structures have not yet been resolved. The biodegradability of these compounds is not yet known. It is known that the concentrations of available nitrogen and phosphorus in seawater limit the growth and activities of hydrocarbon-degrading microorganisms in a marine environment. In other words, the addition of nitrogen and phosphorus fertilizers to an oil-contaminated marine environment can stimulate the biodegradation of spilled oil. This notion was confirmed in the large-scale operation for bioremediation after the oil spill from the Exxon Valdez in Alaska. Many microorganisms capable of degrading petroleum components have been isolated. However, few of them seem to be important for petroleum biodegradation in natural environments. One group of bacteria belonging to the genus

  9. Biodegradation and bioaccumulation of phthalates

    SciTech Connect

    Scholz, N.; Diefenbach, R.

    1995-12-31

    Phthalate esters very often are considered as persistent in the environment. This view is supported by an assumed lack of biodegradability, the high log K{sub ow} values and the assumed high bioaccumulation potential. Results are presented which show phthalates esters to be readily biodegradable even with a non-adapted inoculum. Combined with a lack of relevant bioaccumulation in aquatic organisms, a reconsideration of the environmental impact of these substances is necessary. Special prerequisites for testing poorly water soluble substances are also discussed.

  10. BIODEGRADATION OF TRICHLOROETHYLENE AND INVOLVEMENT OF AN AROMATIC BIODEGRADATIVE PATHWAY

    EPA Science Inventory

    Biodegradation of trichloroethylene (TCE) by the bacterial isolate strain G4 resulted in complete dechlorination of the compound as indicated by the production of inorganic chloride. A component of the water from which strain G4 was isolated that was required for TCE degradation ...

  11. BIODEGRADATION STUDIES OF CARBOXYMETHYL TARTRONATE

    EPA Science Inventory

    Carboxymethyl tartronate (CMT) was shown to be biodegradable in bench-scale activated sludge reactors. After initial exposure to CMT in continuous flow systems an acclimation period of 14 weeks was necessary before efficient degradation occurred. Once acclimated to CMT the biomas...

  12. Biodegradable Pectin/clay Aerogels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodegradable, foamlike materials based on renewable pectin and sodium montmorillonite clay were fabricated through a simple, environmentally friendly freeze-drying process. Addition of multivalent cations (Ca2+ and Al3+) resulted in apparent crosslinking of the polymer, and enhancement of aerogel p...

  13. Sol-gel synthesis and electrospraying of biodegradable (P2O5)55-(CaO)30-(Na2O)15 glass nanospheres as a transient contrast agent for ultrasound stem cell imaging.

    PubMed

    Foroutan, Farzad; Jokerst, Jesse V; Gambhir, Sanjiv S; Vermesh, Ophir; Kim, Hae-Won; Knowles, Jonathan C

    2015-02-24

    Ultrasound imaging is a powerful tool in medicine because of the millisecond temporal resolution and submillimeter spatial resolution of acoustic imaging. However, the current generation of acoustic contrast agents is primarily limited to vascular targets due to their large size. Nanosize particles have the potential to be used as a contrast agent for ultrasound molecular imaging. Silica-based nanoparticles have shown promise here; however, their slow degradation rate may limit their applications as a contrast agent. Phosphate-based glasses are an attractive alternative with controllable degradation rate and easily metabolized degradation components in the body. In this study, biodegradable P2O5-CaO-Na2O phosphate-based glass nanospheres (PGNs) were synthesized and characterized as contrast agents for ultrasound imaging. The structure of the PGNs was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), (31)P magic angle spinning nuclear magnetic resonance ((31)P MAS NMR), and Fourier transform infrared (FTIR) spectroscopy. The SEM images indicated a spherical shape with a diameter size range of 200-500 nm. The XRD, (31)P NMR, and FTIR results revealed the amorphous and glassy nature of PGNs that consisted of mainly Q(1) and Q(2) phosphate units. We used this contrast to label mesenchymal stem cells and determined in vitro and in vivo detection limits of 5 and 9 μg/mL, respectively. Cell counts down to 4000 could be measured with ultrasound imaging with no cytoxicity at doses needed for imaging. Importantly, ion-release studies confirmed these PGNs biodegrade into aqueous media with degradation products that can be easily metabolized in the body. PMID:25625373

  14. Sol-gel Synthesis and Electrospraying of Biodegradable (P2O5)55-(CaO)30-(Na2O)15 Glass Nanospheres as a Transient Contrast Agent for Ultrasound Stem Cell Imaging

    PubMed Central

    Gambhir, Sanjiv S.; Vermesh, Ophir; Kim, Hae-Won; Knowles, Jonathan C.

    2015-01-01

    Ultrasound imaging is a powerful tool in medicine because of the millisecond temporal resolution and sub-millimeter spatial resolution of acoustic imaging. However, the current generation of acoustic contrast agents is primarily limited to vascular targets due to their large size. Nano-size particles have the potential to be used as a contrast agent for ultrasound molecular imaging. Silica-based nanoparticles have shown promise here, however their slow degradation rate may limit their applications as a contrast agent. Phosphate-based glasses are an attractive alternative with controllable degradation rate and easily metabolized degradation components in the body. In this study, biodegradable P2O5-CaO-Na2O phosphate-based glass nanospheres (PGNs) were synthesized and characterized as contrast agents for ultrasound imaging. The structure of the PGNs was characterised using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), 31P nuclear magnetic resonance (31P MAS-NMR), and Fourier transform infrared (FTIR) spectroscopy. The SEM images indicated a spherical shape with a diameter size range of 200-500 nm. The XRD, 31P NMR and FTIR results revealed the amorphous and glassy nature of PGNs that consisted of mainly Q1 and Q2 phosphate units. We used this contrast to label mesenchymal stem cells and determined in vitro and in vivo detection limits of 5 and 9 μg/mL, respectively. Cell counts down to 4000 could be measured with ultrasound imaging with no cytoxicity at doses needed for imaging. Importantly, ion release studies confirmed these PGNs biodegrade into aqueous media with degradation products that can be easily metabolized in the body. PMID:25625373

  15. Biobased and biodegradable polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Qiu, Kaiyan

    In this dissertation, various noncrosslinked and crosslinked biobased and biodegradable polymer nanocomposites were fabricated and characterized. The properties of these polymer nanocomposites, and their relating mechanisms and corresponding applications were studied and discussed in depth. Chapter 1 introduces the research background and objectives of the current research. Chapter 2 presents the development of a novel low cost carbon source for bacterial cellulose (BC) production and fabrication and characterization of biobased polymer nanocomposites using produced BC and soy protein based resins. The carbon source, soy flour extract (SFE), was obtained from defatted soy flour (SF) and BC yield achieved using SFE medium was high. The results of this study showed that SFE consists of five sugars and Acetobacter xylinum metabolized sugars in a specific order. Chapter 3 discusses the fabrication and characterization of biodegradable polymer nanocomposites using BC and polyvinyl alcohol (PVA). These polymer nanocomposites had excellent tensile and thermal properties. Crosslinking of PVA using glutaraldehyde (GA) not only increased the mechanical and thermal properties but the water-resistance. Chapter 4 describes the development and characterization of microfibrillated cellulose (MFC) based biodegradable polymer nanocomposites by blending MFC suspension with PVA. Chemical crosslinking of the polymer nanocomposites was carried out using glyoxal to increase the mechanical and thermal properties as well as to make the PVA partially water-insoluble. Chapter 5 reports the development and characterization of halloysite nanotube (HNT) reinforced biodegradable polymer nanocomposites utilizing HNT dispersion and PVA. Several separation techniques were used to obtain individualized HNT dispersion. The results indicated uniform dispersion of HNTs in both PVA and malonic acid (MA) crosslinked PVA resulted in excellent mechanical and thermal properties of the materials, especially

  16. UV photolysis for accelerating pyridine biodegradation.

    PubMed

    Zhang, Yongming; Chang, Ling; Yan, Ning; Tang, Yingxia; Liu, Rui; Rittmann, Bruce E

    2014-01-01

    Pyridine, a nitrogen-containing heterocyclic compound, is slowly biodegradable, and coupling biodegradation with UV photolysis is a potential means to accelerate its biotransformation and mineralization. The initial steps of pyridine biodegradation involve mono-oxygenation reactions that have molecular oxygen and an intracellular electron carrier as cosubstrates. We employed an internal circulation baffled biofilm reactor for pyridine biodegradation following three protocols: direct biodegradation (B), biodegradation after photolysis (P+B), and biodegradation with succinic acid added (B+S). Succinic acid was the main UV-photolysis product from pyridine, and its catabolic oxidation generates internal electron carriers that may accelerate the initial steps of pyridine biodegradation. Compared with direct biodegradation of pyridine (B), the removal rate for the same concentration of photolyzed pyridine (P+B) was higher by 15 to 43%, depending on the initial pyridine concentrations (increasing through the range of 130 to 310 mg/L). Adding succinic acid alone (B+S) gave results similar to P+B, which supports that succinic acid was the main agent for accelerating the pyridine biodegradation rate. In addition, protocols P+B and B+S were similar in terms of increasing pyridine mineralization over 10 h: 84% and 87%, respectively, which were higher than with protocol B (72%). The positive impact of succinic acid-whether added directly or produced via UV photolysis-confirms that its catabolism, which produced intracellular electron carriers, accelerated the initial steps of pyridine biotransformation. PMID:24364496

  17. Integrated transformations of plant biomass to valuable chemicals, biodegradable polymers and nanoporous carbons

    NASA Astrophysics Data System (ADS)

    Kuznetsov, B. N.; Chesnokov, N. V.; Taraban'ko, V. E.; Kuznetsova, S. A.; Petrov, A. V.

    2013-03-01

    Integrated transformations of wood biomass to valuable chemicals and materials are described. They include the main biomass components separation, the conversion of cellulose to glucose, levulinic acid, biodegradable polymers and lignin - to nanoporous carbons. For wood fractionation on pure cellulose and low molecular mass lignin the methods of catalytic oxidation and exploded autohydrolysis are used. The processes of acid-catalysed hydrolysis of cellulose to glucose and levulinic acid were optimized. New methods of biodegradable polymers synthesis from lactone of levulinic acid and nanoporous carbons from lignin were suggested.

  18. Biodegradable microspheres for parenteral delivery.

    PubMed

    Sinha, V R; Trehan, A

    2005-01-01

    Nowadays, emphasis is being laid to development of controlled release dosage forms. Interest in this technology has increased steadily over the past few years. Although oral administration of drugs is a widely accepted route of drug delivery, bioavailability of drug often varies as a result of gastrointestinal absorption, degradation by first-pass effect, and hostile environment of gastrointestinal tract. Transdermal administration for percutaneous absorption of drug is limited by the impermeable nature of the stratum corneum. Ocular and nasal delivery is also unfavorable because of degradation by enzymes present in eye tissues and nasal mucosa. Hence, the parenteral route is the most viable approach in such cases. Of the various ways of achieving long-term parenteral drug delivery, biodegradable microspheres are one of the better means of controlling the release of drug over a long time. Because of the lipidic nature of liposomes, problems such as limited physical stability and difficulty of freeze-drying are encountered. Similarly, for emulsions, stability on long-term basis and in suspensions, rheological changes during filling, injecting, and storage poses limitation. Also, in all these systems, the release rate cannot be tailored to the needs of the patient. Parenteral controlled-release formulations based on biodegradable microspheres can overcome these problems and can control the release of drug over a predetermined time span, usually in the order of days to weeks to months. Various FDA-approved controlled-release parenteral formulations based on these biodegradable microspheres are available on the market, including Lupron Depot Nutropin Depot and Zoladex. This review covers various molecules encapsulated in biodegradable microspheres for parenteral delivery. PMID:16566705

  19. Engineering Flame Retardant Biodegradable Nanocomposites

    NASA Astrophysics Data System (ADS)

    He, Shan; Yang, Kai; Guo, Yichen; Zhang, Linxi; Pack, Seongchan; Davis, Rachel; Lewin, Menahem; Ade, Harald; Korach, Chad; Kashiwagi, Takashi; Rafailovich, Miriam

    2013-03-01

    Cellulose-based PLA/PBAT polymer blends can potentially be a promising class of biodegradable nanocomposites. Adding cellulose fiber reinforcement can improve mechanical properties of biodegradable plastics, but homogeneously dispersing hydrophilic cellulose in the hydrophobic polymer matrix poses a significant challenge. We here show that resorcinol diphenyl phosphates (RDP) can be used to modify the surface energy, not only reducing phase separation between two polymer kinds but also allowing the cellulose particles and the Halloysite clay to be easily dispersed within polymer matrices to achieve synergy effect using melt blending. Here in this study we describe the use of cellulose fiber and Halloysite clay, coated with RDP surfactant, in producing the flame retardant polymer blends of PBAT(Ecoflex) and PLA which can pass the stringent UL-94 V0 test. We also utilized FTIR, SEM and AFM nanoindentation to elucidate the role RDP plays in improving the compatibility of biodegradable polymers, and to determine structure property of chars that resulted in composites that could have optimized mechanical and thermal properties. Supported by Garcia Polymer Center and NSF Foundation.

  20. Biodegradation of dimethylsilanediol in soils.

    PubMed Central

    Sabourin, C L; Carpenter, J C; Leib, T K; Spivack, J L

    1996-01-01

    The biodegradation potential of [14C]dimethylsilanediol, the monomer unit of polydimethylsiloxane, in soils was investigated. Dimethylsilanediol was found to be biodegraded in all of the tested soils, as monitored by the production of 14CO2. When 2-propanol was added to the soil as a carbon source in addition to [14C]dimethylsilanediol, the production of 14CO2 increased. A method for the selection of primary substrates that support cometabolic degradation of a target compound was developed. By this method, the activity observed in the soils was successfully transferred to liquid culture. A fungus, Fusarium oxysporum Schlechtendahl, and a bacterium, an Arthrobacter species, were isolated from two different soils, and both microorganisms were able to cometabolize [14C]dimethylsilanediol to 14CO2 in liquid culture. In addition, the Arthrobacter sp. that was isolated grew on dimethylsulfone, and we believe that this is the first reported instance of a microorganism using dimethylsulfone as its primary carbon source. Previous evidence has shown that polydimethylsiloxane is hydrolyzed in soil to the monomer, dimethylsilanediol. Now, biodegradation of dimethylsilanediol in soil has been demonstrated. PMID:8953708

  1. Synthesis, characterizations, and biocompatibility of block poly(ester-urethane)s based on biodegradable poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3/4HB) and poly(ε-caprolactone).

    PubMed

    Qiu, Handi; Li, Dandan; Chen, Xi; Fan, Kaiyan; Ou, Wenfeng; Chen, Kevin C; Xu, Kaitian

    2013-01-01

    A type of block poly(ester-urethane)s (abbreviated as PUBC) based on bacterial copolyester poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3/4HB) and biodegradable poly(ε-caprolactone) (PCL) was synthesized by melting polymerization using 1,6-hexamethylene diisocyanate (HDI) as the coupling agent, with different 3HB, 4HB and PCL contents and segment lengths. Stannous octanoate (Sn(Oct)(2)) was used as catalyst. The chemical structure, molecular weight and thermal property were characterized by (1)H NMR, FTIR GPC, DSC and TGA. DSC analysis revealed that the PUBC polyurethanes exhibit amorphous to semi-crystalline (20.9% crystallinity degree) with T(g) range from -39.7 to -21.5 °C. The hydrophilicity was investigated by static contact angle of deionized water and CH(2)I(2). The obtained PUBCs are hydrophobic (water contact angle 73.7-90.2°). Platelet adhesion study and plasma recalcification time revealed that the block polyurethanes possess hemastasis ability. CCK-8 assay illuminated that the no cytotoxic polyurethanes maintain rat aortic smooth muscle cells (RaSMCs) good viability. It was found that the 4HB content in the materials is an important factor to affect the sustainable cell viability. PMID:22826204

  2. Synthesis of a novel zwitterionic biodegradable poly (α,β-L-aspartic acid) derivative with some L-histidine side-residues and its resistance to non-specific protein adsorption.

    PubMed

    Wang, Xiaojuan; Wu, Guolin; Lu, Caicai; Wang, Yinong; Fan, Yunge; Gao, Hui; Ma, Jianbiao

    2011-08-01

    A novel zwitterionic polypeptide derivative, denoted as His-PAsp/PAsp, was successfully synthesized by amidation of Poly (α,β-L-aspartic acid) with L-histidine methyl ester. Turbidity, zeta potential and ¹H NMR measurements were used to study the aggregation behaviors of His-PAsp/PAsp under different pH values. The modified polypeptide derivative composed of electro-negatively carboxylic and electro-positively imidazole residues randomly so as to bear opposite charges at pH values above or below the isoelectric point. When the zwitterionic polypeptide was coated on silicon wafer as a model substrate material, the absorption resistance of fibrinogen, a blood protein resulting in the blood coagulation cascade, on the coated surface was measured. It was found that the adsorption amount of fibrinogen on the polypeptide-coated surface depended on the dose of the polypeptide on silicon wafer. Obvious resistance of the fibrinogen adsorption on the polypeptide-coated surface was observed. Since its good biodegradability and superior anti-protein-fouling property, this pH-responsive zwitterionic polypeptide is a promising candidate for surface modification in many biomedical applications, including medical implants, drug delivery carriers, and biosensors. PMID:21536417

  3. Synthesis, characterization and drug release of biocompatible/biodegradable non-toxic poly(urethane urea)s based on poly(epsilon-caprolactone)s and lysine-based diisocyanate.

    PubMed

    Reddy, Thatiparti Thimma; Kano, Arihiro; Maruyama, Atsushi; Takahara, Atsushi

    2010-01-01

    Segmented poly(urethane urea)s (SPUUs) based on aliphatic diisocyanato (2,6-diisocyanato methyl caproate (lysine-based diisocyanate, LDI)), poly(epsilon-caprolactone diol)s (PCLs) with molecular weights 530, 1250 and 2000, and 1,4-butanediamine were synthesized in absence of catalyst. The resulting SPUUs, with different soft segment length, were characterized by suitable analytical techniques. The synthesized SPUUs had high molecular weights, low glass-transition temperatures (biodegradable properties that might be employed in wound dressing, drug delivery and tissue-engineering applications. PMID:20534197

  4. Biodegradation of high molecular weight polylactic acid

    NASA Astrophysics Data System (ADS)

    Stloukal, Petr; Koutny, Marek; Sedlarik, Vladimir; Kucharczyk, Pavel

    2012-07-01

    Polylactid acid seems to be an appropriate replacement of conventional non-biodegradable synthetic polymer primarily due to comparable mechanical, thermal and processing properties in its high molecular weight form. Biodegradation of high molecular PLA was studied in compost for various forms differing in their specific surface area. The material proved its good biodegradability under composting conditions and all investigated forms showed to be acceptable for industrial composting. Despite expectations, no significant differences in resulting mineralizations were observed for fiber, film and powder sample forms with different specific surface areas. The clearly faster biodegradation was detected only for the thin coating on porous material with high specific surface area.

  5. Synthesis, Characteristics and Potential Application of Poly(β-Amino Ester Urethane)-Based Multiblock Co-Polymers as an Injectable, Biodegradable and pH/Temperature-Sensitive Hydrogel System.

    PubMed

    Huynh, Cong Truc; Nguyen, Minh Khanh; Jeong, In Ki; Kim, Sung Wan; Lee, Doo Sung

    2012-01-01

    Physical polymeric hydrogels have significant potential for use as injectable depot drug/protein-delivery systems. In this study, a series of novel injectable, biodegradable and pH/temperature-sensitive multiblock co-polymer physical hydrogels composed of poly(ethylene glycol) (PEG) and poly(β-amino ester urethane) (PEU) was synthesized by the polyaddition between the isocyanate groups of 1,6-diisocyanato hexamethylene and the hydroxyl groups of PEG and a synthesized monomer BTB (or ETE) in chloroform in the presence of dibutyltin dilaurate as a catalyst. The synthesized co-polymers were characterized by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy and gel-permeation chromatography. Aqueous solutions of the co-polymers showed a sol-to-gel phase transition with increasing pH and a gel-to-sol phase transition with increasing temperature. The gel regions covered the physiological conditions (37°C, pH 7.4) and could be controlled by changing the molecular weight of PEG, PEG/PEU ratio and co-polymer solution concentration. A gel formed rapidly in situ after injecting the co-polymer solution subcutaneously into SD rats and remained for more than 2 weeks in the body. The cytotoxicity tests confirmed the non-cytotoxicity of this co-polymer hydrogel. The controlled in vitro release of the model anticancer drug, doxorubicin, from this hydrogel occurred over a 7-day period. This hydrogel is a potential candidate for biomedical applications and drug/protein-delivery systems. PMID:21619729

  6. Biodegradable fixation of rabbit osteotomies.

    PubMed

    Vainionpää, S; Vihtonen, K; Mero, M; Pätiälä, H; Rokkanen, P; Kilpikari, J; Törmälä, P

    1986-06-01

    Osteotomies of the tibial diaphysis were operatively fixed with biodegradable implants in 44 rabbits. Polyglycolic acid (PGA)/polylactic acid (PLA) copolymer implants reinforced with 7 per cent carbon fibre and overlaid with gold were used in 24 rabbits. Poly-beta-hydroxy butyric acid (PHBA) with carbon fibre reinforcement and gold surfacing were used in 20 rabbits. No external support was used. Unsatisfactory results were achieved with the PGA/PLA copolymer implants. Better results were achieved in 15 out of 20 rabbits whose osteotomies were fixed with carbon fibre-reinforced PHBA implants. PMID:3739665

  7. Biodegradable stents in gastrointestinal endoscopy

    PubMed Central

    Lorenzo-Zúñiga, Vicente; Moreno-de-Vega, Vicente; Marín, Ingrid; Boix, Jaume

    2014-01-01

    Biodegradable stents (BDSs) are an attractive option to avoid ongoing dilation or surgery in patients with benign stenoses of the small and large intestines. The experience with the currently the only BDS for endoscopic placement, made of Poly-dioxanone, have shown promising results. However some aspects should be improved as are the fact that BDSs lose their radial force over time due to the degradable material, and that can cause stent-induced mucosal or parenchymal injury. This complication rate and modest clinical efficacy has to be carefully considered in individual patients prior to placement of BDSs. Otherwise, the price of these stents therefore it is nowadays an important limitation. PMID:24605020

  8. ANAEROBIC BIODEGRADABILITY OF NON-PETROLEUM OILS.

    EPA Science Inventory

    Research has demonstrated that vegetable oils are amenable to anaerobic biodegradation. This is in contrast to petroleum oils. Vegetable oils are already oxygenated because they are composed of fatty acids and glycerols, which contribute to the biodegradability. A strategy has be...

  9. Nylon biodegradation by lignin-degrading fungi.

    PubMed Central

    Deguchi, T; Kakezawa, M; Nishida, T

    1997-01-01

    The biodegradation of nylon by lignin-degrading fungi was investigated. The fungus IZU-154 significantly degraded nylon-66 membrane under ligninolytic conditions. Nuclear magnetic resonance analysis showed that four end groups, CHO, NHCHO, CH3, and CONH2, were formed in the biodegraded nylon-66 membranes, suggesting that nylon-66 was degraded oxidatively. PMID:8979361

  10. Biodegradable polymers for electrospinning: towards biomedical applications.

    PubMed

    Kai, Dan; Liow, Sing Shy; Loh, Xian Jun

    2014-12-01

    Electrospinning has received much attention recently due to the growing interest in nano-technologies and the unique material properties. This review focuses on recent progress in applying electrospinning technique in production of biodegradable nanofibers to the emerging field of biomedical. It first introduces the basic theory and parameters of nanofibers fabrication, with focus on factors affecting the morphology and fiber diameter of biodegradable nanofibers. Next, commonly electrospun biodegradable nanofibers are discussed, and the comparison of the degradation rate of nanoscale materials with macroscale materials are highlighted. The article also assesses the recent advancement of biodegradable nanofibers in different biomedical applications, including tissue engineering, drug delivery, biosensor and immunoassay. Future perspectives of biodegradable nanofibers are discussed in the last section, which emphasizes on the innovation and development in electrospinning of hydrogels nanofibers, pore size control and scale-up productions. PMID:25491875

  11. Chemical dispersants: Oil biodegradation friend or foe?

    PubMed

    Rahsepar, Shokouh; Smit, Martijn P J; Murk, Albertinka J; Rijnaarts, Huub H M; Langenhoff, Alette A M

    2016-07-15

    Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil biodegradation by alkane and/or aromatic degrading bacterial culture in artificial seawater at different dispersant to oil ratios (DORs). Our results show that dispersant addition did not enhance oil biodegradation. At DOR 1:20, biodegradation was inhibited, especially when only the alkane degrading culture was present. With a combination of cultures, this inhibition was overcome after 10days. This indicates that initial inhibition of oil biodegradation can be overcome when different bacteria are present in the environment. We conclude that the observed inhibition is related to the enhanced dissolution of aromatic compounds into the water, inhibiting the alkane degrading bacteria. PMID:27156037

  12. Biodegradation-inspired bioproduction of methylacetoin and 2-methyl-2,3-butanediol

    PubMed Central

    Jiang, Xinglin; Zhang, Haibo; Yang, Jianming; Zheng, Yanning; Feng, Dexin; Liu, Wei; Xu, Xin; Cao, Yujin; Zou, Huibin; Zhang, Rubin; Cheng, Tao; Jiao, Fengjiao; Xian, Mo

    2013-01-01

    Methylacetoin (3-hydroxy-3-methylbutan-2-one) and 2-methyl-2,3-butanediol are currently obtained exclusively via chemical synthesis. Here, we report, to the best of our knowledge, the first alternative route, using engineered Escherichia coli. The biological synthesis of methylacetoin was first accomplished by reversing its biodegradation, which involved modifying the enzyme complex involved, switching the reaction substrate, and coupling the process to an exothermic reaction. 2-Methyl-2,3-butanediol was then obtained by reducing methylacetoin by exploiting the substrate promiscuity of acetoin reductase. A complete biosynthetic pathway from renewable glucose and acetone was then established and optimized via in vivo enzyme screening and host metabolic engineering, which led to titers of 3.4 and 3.2 g l−1 for methylacetoin and 2-methyl-2,3-butanediol, respectively. This work presents a biodegradation-inspired approach to creating new biosynthetic pathways for small molecules with no available natural biosynthetic pathway. PMID:23945710

  13. Biodegradation of fluorinated alkyl substances.

    PubMed

    Frömel, Tobias; Knepper, Thomas P

    2010-01-01

    The incorporation of fluorine into organic molecules entails both positive and adverse effects. Although fluorine imparts positive and unique properties such as water-and oil-repellency and chemical stability, adverse effects often pervade members of this compound class. A striking property of long perfluoroalkyl chains is their very pronounced environmental persistence. The present review is the first one designed to summarize recent accomplishments in the field of biodegradation of fluorine-containing surfactants, their metabolites, and structural analogs. The pronounced scientific and public interest in these chemicals has given impetus to undertake numerous degradation studies to assess the sources and origins of different fluorinated analog chemical known to exist in the environment. It was shown that biodegradation plays an important role in understanding how fluorinated substances reach the environment and, once they do, what their fate is. Today, PFOS and PFOA are ubiquitously detected as environmental contaminants. Their prominence as contaminants is mainly due to their extreme persistence, which is linked to their perfluoroalkyl chain length. It appears that desulfonation of a highly fluorinated surfactants can be achieved if an α-situated H atom, in relation to the sulfonate group, is present, at least under sulfur-limiting conditions. Molecules that are less heavily fluorinated can show very complex metabolic behavior, as is the case for fluorotelomer alcohols. These compounds are degraded via different but simultaneous pathways, which produce different stable metabolites, one of which is the respective perfluoroalkanoate (8:2-FTOH is transformed to PFOA). Preliminary screening tests indicate that fluorinated functional groups, such as the trifluoromethoxy group and the p-(trifluoromethyl)phenoxy group, may be useful implementations in novel, environmentally benign fluorosurfactants. More specifically, trifluoromethoxy groups constitute a substitute

  14. Design Strategies for Fluorescent Biodegradable Polymeric Biomaterials

    PubMed Central

    Zhang, Yi; Yang, Jian

    2013-01-01

    The marriage of biodegradable polymer and fluorescent imaging has resulted in an important area of polymeric biomaterials: biodegradable fluorescent polymers. Researchers have put significant efforts on developing versatile fluorescent biomaterials due to their promising in biological/biomedical labeling, tracking, monitoring, imaging, and diagnostic applications, especially in drug delivery, tissue engineering, and cancer imaging applications. Biodegradable fluorescent polymers can function not only as implant biomaterials but also as imaging probes. Currently, there are two major classes of biodegradable polymers used as fluorescent materials. The first class is the combination of non-fluorescent biodegradable polymers and fluorescent agents such as organic dyes and quantum dots. Another class of polymers shows intrinsic photoluminescence as polymers by themselves carrying integral fluorescent chemical structures in or pendent to their polymer backbone, such as Green Fluorescent protein (GFP), and the recently developed biodegradable photoluminescent polymer (BPLP). Thus there is no need to conjugate or encapsulate additional fluorescent materials for the latter. In the present review, we will review the fluorescent biodegradable polymers with emphases on material fluorescence mechanism, design criteria for fluorescence, and their cutting-edge applications in biomedical engineering. We expect that this review will provide insightful discussion on the fluorescent biomaterial design and lead to innovations for the development of the next generation of fluorescent biomaterials and fluorescence-based biomedical technology. PMID:23710326

  15. Biodegradable and compostable alternatives to conventional plastics

    PubMed Central

    Song, J. H.; Murphy, R. J.; Narayan, R.; Davies, G. B. H.

    2009-01-01

    Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers. The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all ‘good’ or petrochemical-based products are all ‘bad’. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemical-based counterparts. Specific examples are given from new research on biodegradability in simulated ‘home’ composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted. PMID:19528060

  16. New perspectives in plastic biodegradation.

    PubMed

    Sivan, Alex

    2011-06-01

    During the past 50 years new plastic materials, in various applications, have gradually replaced the traditional metal, wood, leather materials. Ironically, the most preferred property of plastics--durability--exerts also the major environmental threat. Recycling has practically failed to provide a safe solution for disposal of plastic waste (only 5% out of 1 trillion plastic bags, annually produced in the US alone, are being recycled). Since the most utilized plastic is polyethylene (PE; ca. 140 million tons/year), any reduction in the accumulation of PE waste alone would have a major impact on the overall reduction of the plastic waste in the environment. Since PE is considered to be practically inert, efforts were made to isolate unique microorganisms capable of utilizing synthetic polymers. Recent data showed that biodegradation of plastic waste with selected microbial strains became a viable solution. PMID:21356588

  17. Engineered biosynthesis of biodegradable polymers.

    PubMed

    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

  18. Collapse pressures of biodegradable stents.

    PubMed

    Venkatraman, Subbu; Poh, Tan Lay; Vinalia, Tjong; Mak, Koon Hou; Boey, Freddy

    2003-05-01

    Biodegradable stent prototypes were produced from poly L-lactic acid polymers with different molecular weights. The effects of molecular weight, drug incorporation and stent design on the collapse pressure of the stents were evaluated. While molecular weights did not show a significant effect on the collapse pressure of the stents, drug incorporation at high percentage decreased the collapse pressure of the stents substantially. Cryogenic fracture surfaces showed significant drug agglomeration as the concentration increased. The design of the stent was also found to a have significant effect on the collapse pressure. The stent produced from the same material has a higher collapse pressure when the load bearing surface area is increased. PMID:12628831

  19. Oxidative biodegradation pathways of PAHs

    SciTech Connect

    Cerniglia, C.E.

    1993-12-31

    Polycyclic aromatic hydrocarbons (PAHs) constitute a class of hazardous organic chemical consisting of three of more fused benzene rings in linear, angular and cluster arrangements. PAHs mostly occur as a result of fossil fuel combustion, as by-product of industrial processing and during the cooking of foods. A catabolically diverse microbial community, consisting of bacteria, fungi and algae, metabolizes aromatic compounds. Molecular oxygen is essential for the initial hydroxylation of polycyclic aromatic hydrocarbons by microorganisms. In contrast to bacteria, filamentous fungi use hydroxylation as a prelude to detoxification rather than to catabolism and assimilation. The biochemical principles underlying the degradation of polycyclic aromatic hydrocarbons will be discussed. The oxidative pathways of polycyclic aromatic hydrocarbon catabolism will be discussed. Studies will be presented on the relationship between the chemical structure of the polycyclic aromatic hydrocarbon and the rate of polycyclic aromatic hydrocarbon biodegradation in aquatic and terrestrial ecosystems.

  20. Biomedical Applications of Biodegradable Polymers

    PubMed Central

    Ulery, Bret D.; Nair, Lakshmi S.; Laurencin, Cato T.

    2011-01-01

    Utilization of polymers as biomaterials has greatly impacted the advancement of modern medicine. Specifically, polymeric biomaterials that are biodegradable provide the significant advantage of being able to be broken down and removed after they have served their function. Applications are wide ranging with degradable polymers being used clinically as surgical sutures and implants. In order to fit functional demand, materials with desired physical, chemical, biological, biomechanical and degradation properties must be selected. Fortunately, a wide range of natural and synthetic degradable polymers has been investigated for biomedical applications with novel materials constantly being developed to meet new challenges. This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications. PMID:21769165

  1. Biodegradation of poly(etherurethanes)

    NASA Astrophysics Data System (ADS)

    Arora, Neha; Ali, Asif; Jana, Nandan Kumar; Basak, Piyali

    2013-06-01

    Polyurethanes have found widespread applications in biomedical engineering, such as implant coat material, catheter coat material and drug delivery among others, for their biocompatibility and biodegradability. These polyurethanes have been found to degrade with time when implanted. For medical purpose, studies on degradation of polyurethanes have attracted great interest. Hydrolytic, oxidative and enzymatic degradation of polyurethane membrane was investigated for one week. The in vitro degradation medium used was such that mimic in vivo conditions. Hydrolytic degradation was performed in simulated body fluid at 37°C. Oxidative degradation was performed with 0.1M cobalt chloride in hydrogen peroxide at 37°C. Enzymatic degradation was performed using esterase enzyme (40Units/ml) in phosphate buffer solution (pH 7.4) at 37°C. The degradation was characterized by x ray diffraction. Results of polyurethane degradation with three types of degrading medium were compared.

  2. Biodegradation of halogenated organic compounds.

    PubMed Central

    Chaudhry, G R; Chapalamadugu, S

    1991-01-01

    In this review we discuss the degradation of chlorinated hydrocarbons by microorganisms, emphasizing the physiological, biochemical, and genetic basis of the biodegradation of aliphatic, aromatic, and polycyclic compounds. Many environmentally important xenobiotics are halogenated, especially chlorinated. These compounds are manufactured and used as pesticides, plasticizers, paint and printing-ink components, adhesives, flame retardants, hydraulic and heat transfer fluids, refrigerants, solvents, additives for cutting oils, and textile auxiliaries. The hazardous chemicals enter the environment through production, commercial application, and waste. As a result of bioaccumulation in the food chain and groundwater contamination, they pose public health problems because many of them are toxic, mutagenic, or carcinogenic. Although synthetic chemicals are usually recalcitrant to biodegradation, microorganisms have evolved an extensive range of enzymes, pathways, and control mechanisms that are responsible for catabolism of a wide variety of such compounds. Thus, such biological degradation can be exploited to alleviate environmental pollution problems. The pathways by which a given compound is degraded are determined by the physical, chemical, and microbiological aspects of a particular environment. By understanding the genetic basis of catabolism of xenobiotics, it is possible to improve the efficacy of naturally occurring microorganisms or construct new microorganisms capable of degrading pollutants in soil and aquatic environments more efficiently. Recently a number of genes whose enzyme products have a broader substrate specificity for the degradation of aromatic compounds have been cloned and attempts have been made to construct gene cassettes or synthetic operons comprising these degradative genes. Such gene cassettes or operons can be transferred into suitable microbial hosts for extending and custom designing the pathways for rapid degradation of recalcitrant

  3. Biodegradation of halogenated organic compounds.

    PubMed

    Chaudhry, G R; Chapalamadugu, S

    1991-03-01

    In this review we discuss the degradation of chlorinated hydrocarbons by microorganisms, emphasizing the physiological, biochemical, and genetic basis of the biodegradation of aliphatic, aromatic, and polycyclic compounds. Many environmentally important xenobiotics are halogenated, especially chlorinated. These compounds are manufactured and used as pesticides, plasticizers, paint and printing-ink components, adhesives, flame retardants, hydraulic and heat transfer fluids, refrigerants, solvents, additives for cutting oils, and textile auxiliaries. The hazardous chemicals enter the environment through production, commercial application, and waste. As a result of bioaccumulation in the food chain and groundwater contamination, they pose public health problems because many of them are toxic, mutagenic, or carcinogenic. Although synthetic chemicals are usually recalcitrant to biodegradation, microorganisms have evolved an extensive range of enzymes, pathways, and control mechanisms that are responsible for catabolism of a wide variety of such compounds. Thus, such biological degradation can be exploited to alleviate environmental pollution problems. The pathways by which a given compound is degraded are determined by the physical, chemical, and microbiological aspects of a particular environment. By understanding the genetic basis of catabolism of xenobiotics, it is possible to improve the efficacy of naturally occurring microorganisms or construct new microorganisms capable of degrading pollutants in soil and aquatic environments more efficiently. Recently a number of genes whose enzyme products have a broader substrate specificity for the degradation of aromatic compounds have been cloned and attempts have been made to construct gene cassettes or synthetic operons comprising these degradative genes. Such gene cassettes or operons can be transferred into suitable microbial hosts for extending and custom designing the pathways for rapid degradation of recalcitrant

  4. Preparation and degradation mechanisms of biodegradable polymer: a review

    NASA Astrophysics Data System (ADS)

    Zeng, S. H.; Duan, P. P.; Shen, M. X.; Xue, Y. J.; Wang, Z. Y.

    2016-07-01

    Polymers are difficult to degrade completely in Nature, and their catabolites may pollute the environment. In recent years, biodegradable polymers have become the hot topic in people's daily life with increasing interest, and a controllable polymer biodegradation is one of the most important directions for future polymer science. This article presents the main preparation methods for biodegradable polymers and discusses their degradation mechanisms, the biodegradable factors, recent researches and their applications. The future researches of biodegradable polymers are also put forward.

  5. Intimately coupling of photolysis accelerates nitrobenzene biodegradation, but sequential coupling slows biodegradation.

    PubMed

    Yang, Lihui; Zhang, Yongming; Bai, Qi; Yan, Ning; Xu, Hua; Rittmann, Bruce E

    2015-04-28

    Photo(cata)lysis coupled with biodegradation is superior to photo(cata)lysis or biodegradation alone for removal of recalcitrant organic compounds. The two steps can be carried out sequentially or simultaneously via intimate coupling. We studied nitrobenzene (NB) removal and mineralization to evaluate why intimate coupling of photolysis with biodegradation was superior to sequential coupling. Employing an internal circulation baffled biofilm reactor, we compared direct biodegradation (B), biodegradation after photolysis (P+B), simultaneous photolysis and biodegradation (P&B), and biodegradation with nitrophenol (NP) and oxalic acid (OA) added individually and simultaneously (B+NP, B+OA, and B+NP+OA); NP and OA were NB's main UV-photolysis products. Compared with B, the biodegradation rate P+B was lower by 13-29%, but intimately coupling (P&B) had a removal rate that was 10-13% higher; mineralization showed similar trends. B+OA gave results similar to P&B, B+NP gave results similar to P+B, and B+OA+NP gave results between P+B and P&B, depending on the amount of OA and NP added. The photolysis product OA accelerated NB biodegradation through a co-substrate effect, but NP was inhibitory. Although decreasing the UV photolysis time could minimize the inhibition impact of NP in P+B, P&B gave the fastest removal of NB by accentuating the co-substrate effect of OA. PMID:25661172

  6. MOLECULAR BASIS OF BIODEGRADATION OF CHLOROAROMATIC COMPOUNDS

    EPA Science Inventory

    Chlorinated aromatic hydrocarbons are widely used in industry and agriculture and comprise the bulk of environmental pollutants. lthough simple aromatic compounds are biodegradable by a variety of degradative pathways, their halogenated counterparts are more resistant to bacteria...

  7. MOLECULAR BASIS OF BIODEGRADATION OF CHLOROAROMATIC COMPOUNDS

    EPA Science Inventory

    Chlorinated aromatic hydrocarbons are widely used in industry and agriculture, and comprise the bulk of environmental pollutants. Although simple aromatic compounds are biodegradable by a variety of degradative pathways, their halogenated counterparts are more resistant to bacter...

  8. Biodegradation of rocket propellent waste, ammonium perchlorate

    NASA Technical Reports Server (NTRS)

    Naqui, S. M. Z.

    1975-01-01

    The impact of the biodegradation rate of ammonium perchlorate on the environment was studied in terms of growth, metabolic rate, and total biomass of selected animal and plant species. Brief methodology and detailed results are presented.

  9. ENHANCED BIODEGRADATION THROUGH IN-SITU AERATION

    EPA Science Inventory

    This presentation provided an overview of enhanced aerobic bioremediation using in-situ aeration or venting. The following topics were covered: (1) Basic discussion on biodegradation and respiration testing; (2) Basic discussion on volatilization, rate-limited mass transport, an...

  10. OPTIMIZING BTEX BIODEGRADATION UNDER DENITRIFYING CONDITIONS

    EPA Science Inventory

    Laboratory tests were conducted to determine optimum conditions for benzene, toluene, ethylbenzene, and xylene (collectively known as BTEX) biodegradation by aquifer microorganisms under denitrifying conditions. Microcosms, constructed with aquifer samples from Traverse City, Mic...

  11. Bionemo: molecular information on biodegradation metabolism

    PubMed Central

    Carbajosa, Guillermo; Trigo, Almudena; Valencia, Alfonso; Cases, Ildefonso

    2009-01-01

    Bionemo (http://bionemo.bioinfo.cnio.es) stores manually curated information about proteins and genes directly implicated in the Biodegradation metabolism. When possible, the database includes information on sequence, domains and structures for proteins; and sequence, regulatory elements and transcription units for genes. Thus, Bionemo is a unique resource that complements other biodegradation databases such as the University of Minessota Biocatalysis/Biodegradation Database, or Metarouter, which focus more on the biochemical aspects of biodegradation than in the nature of the biomolecules carrying out the reactions. Bionemo has been built by manually associating sequences database entries to biodegradation reactions, using the information extracted from published articles. Information on transcription units and their regulation was also extracted from the literature for biodegradation genes, and linked to the underlying biochemical network. In its current version, Bionemo contains sequence information for 324 reactions and transcription regulation information for more than 100 promoters and 100 transcription factors. The information in the Bionemo database is available via a web server and the full database is also downloadable as a PostgresSQL dump. To facilitate the programmatic use of the information contained in the database, an object-oriented Perl API is also provided. PMID:18986994

  12. Anaerobic biodegradation of hexazinone in four sediments.

    PubMed

    Wang, Huili; Xu, Shuxia; Tan, Chengxia; Wang, Xuedong

    2009-05-30

    Anaerobic biodegradation of hexazinone was investigated in four sediments (L1, L2, Y1 and Y2). Results showed that the L2 sediment had the highest biodegradation potential among four sediments. However, the Y1 and Y2 sediments had no capacity to biodegrade hexazinone. Sediments with rich total organic carbon, long-term contamination history by hexazinone and neutral pH may have a high biodegradation potential because the former two factors can induce the growth of microorganisms responsible for biodegradation and the third factor can offer suitable conditions for biodegradation. The addition of sulfate or nitrate as electron acceptors enhanced hexazinone degradation. As expected, the addition of electron donors (lactate, acetate or pyruvate) substantially inhibited the degradation. In natural environmental conditions, the effect of intermediate A [3-(4-hydroxycyclohexyl)-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H, 3H)dione] on anaerobic hexazinone degradation was negligible because of its low level. PMID:18824297

  13. Physicochemical properties and biodegradability of crude oil

    SciTech Connect

    Sugiura, Keiji; Ishihara, Masami; Shimauchi, Toshitsugu; Harayama, Shigeaki

    1997-01-01

    The biodegradation of four different crude oil samples, namely, Arabian light, Dubai, Maya, and Shengli, by acinetobacter sp. T4 and by a microbial consortium called SM8 was examined. SM8 exhibited higher activity than Acinetobacter for the biodegradation of all four crude oil samples. The degree of biodegradation of crude oil components differed according to the crude oil, the saturated fraction being more susceptible to biodegradation than the aromatic fraction in all the crude oil samples. The extent of biodegradation by acinetobacter and SM8 was found to be in the order of Arabian light > Dubai > Maya = Shengli; the crude oil samples with higher APl gravity being more susceptible to biodegradation. Saturated compounds of smaller molecular weight were preferentially degraded by both cultures. Acinetobacter could not degrade polycyclic aromatic compounds in the crude oil samples such as (alkyl)naphthalenes, (alky)phenanthrenes, (alkyl)fluorenes, and (alkyl)dibenzothiophenes. However, this strain was capable of degrading more than 10% of the molecules in the aromatic fraction of Arabian light crude oil. An NMR analysis demonstrated that the alkyl side chain of some aromatic molecules was degraded by this organism. In contrast, SM8 degraded the polycyclic aromatic compounds in the crude oil samples, the extent of degradation being in the order of Maya > Shengli > Arabian light > Dubai. 17 refs., 4 figs., 4 tabs.

  14. Substrate inhibition kinetics of phenol biodegradation

    SciTech Connect

    Goudar, C.T.; Ganji, S.H.; Pujar, B.G.; Strevett, K.A.

    2000-02-01

    Phenol biodegradation was studied in batch experiments using an acclimated inoculum and initial phenol concentrations ranging from 0.1 to 1.3 g/L. Phenol depletion an associated microbial growth were monitored over time to provide information that was used to estimate the kinetics of phenol biodegradation. Phenol inhibited biodegradation at high concentrations, and a generalized substrate inhibition model based on statistical thermodynamics was used to describe the dynamics of microbial growth in phenol. For experimental data obtained in this study, the generalized substrate inhibition model reduced to a form that is analogous to the Andrews equation, and the biokinetic parameters {micro}{sub max}, maximum specific growth; K{sub s}, saturation constant; and K{sub i}, inhibition constant were estimated as 0.251 h{sup {minus}1}, 0.011 g/L, and 0.348 g/L, respectively, using a nonlinear least squares technique. Given the wide variability in substrate inhibition models used to describe phenol biodegradation, an attempt was made to justify selection of particular model based on theoretical considerations. Phenol biodegradation data from nine previously published studies were used in the generalized substrate inhibition model to determine the appropriate form of the substrate inhibition model. In all nine cases, the generalized substrate inhibition model reduced to a form analogous to the Andrews equation suggesting the suitability of the Andrews equation to describe phenol biodegradation data.

  15. Biodegradability of commercial and weathered diesel oils

    PubMed Central

    Mariano, Adriano Pinto; Bonotto, Daniel Marcos; de Franceschi de Angelis, Dejanira; Pirôllo, Maria Paula Santos; Contiero, Jonas

    2008-01-01

    This work aimed to evaluate the capability of different microorganisms to degrade commercial diesel oil in comparison to a weathered diesel oil collected from the groundwater at a petrol station. Two microbiological methods were used for the biodegradability assessment: the technique based on the redox indicator 2,6 -dichlorophenol indophenol (DCPIP) and soil respirometric experiments using biometer flasks. In the former we tested the bacterial cultures Staphylococcus hominis, Kocuria palustris, Pseudomonas aeruginosa LBI, Ochrobactrum anthropi and Bacillus cereus, a commercial inoculum, consortia obtained from soil and groundwater contaminated with hydrocarbons and a consortium from an uncontaminated area. In the respirometric experiments it was evaluated the capability of the native microorganisms present in the soil from a petrol station to biodegrade the diesel oils. The redox indicator experiments showed that only the consortia, even that from an uncontaminated area, were able to biodegrade the weathered diesel. In 48 days, the removal of the total petroleum hydrocarbons (TPH) in the respirometric experiments was approximately 2.5 times greater when the commercial diesel oil was used. This difference was caused by the consumption of labile hydrocarbons, present in greater quantities in the commercial diesel oil, as demonstrated by gas chromatographic analyses. Thus, results indicate that biodegradability studies that do not consider the weathering effect of the pollutants may over estimate biodegradation rates and when the bioaugmentation is necessary, the best strategy would be that one based on injection of consortia, because even cultures with recognised capability of biodegrading hydrocarbons may fail when applied isolated. PMID:24031193

  16. Evaluation of biodegradation-promoting additives for plastics.

    PubMed

    Selke, Susan; Auras, Rafael; Nguyen, Tuan Anh; Castro Aguirre, Edgar; Cheruvathur, Rijosh; Liu, Yan

    2015-03-17

    Biodegradation-promoting additives for polymers are increasingly being used around the world with the claim that they effectively render commercial polymers biodegradable. However, there is a lot of uncertainty about their effectiveness in degrading polymers in different environments. In this study, we evaluated the effect of biodegradation-promoting additives on the biodegradation of polyethylene (PE) and polyethylene terephthalate (PET). Biodegradation was evaluated in compost, anaerobic digestion, and soil burial environments. None of the five different additives tested significantly increased biodegradation in any of these environments. Thus, no evidence was found that these additives promote and/or enhance biodegradation of PE or PET polymers. So, anaerobic and aerobic biodegradation are not recommended as feasible disposal routes for nonbiodegradable plastics containing any of the five tested biodegradation-promoting additives. PMID:25723056

  17. Biodegradability and biodegradation rate of poly(caprolactone)-starch blend and poly(butylene succinate) biodegradable polymer under aerobic and anaerobic environment.

    PubMed

    Cho, H S; Moon, H S; Kim, M; Nam, K; Kim, J Y

    2011-03-01

    The biodegradability and the biodegradation rate of two kinds biodegradable polymers; poly(caprolactone) (PCL)-starch blend and poly(butylene succinate) (PBS), were investigated under both aerobic and anaerobic conditions. PCL-starch blend was easily degraded, with 88% biodegradability in 44 days under aerobic conditions, and showed a biodegradation rate of 0.07 day(-1), whereas the biodegradability of PBS was only 31% in 80 days under the same conditions, with a biodegradation rate of 0.01 day(-1). Anaerobic bacteria degraded well PCL-starch blend (i.e., 83% biodegradability for 139 days); however, its biodegradation rate was relatively slow (6.1 mL CH(4)/g-VS day) compared to that of cellulose (13.5 mL CH(4)/g-VS day), which was used as a reference material. The PBS was barely degraded under anaerobic conditions, with only 2% biodegradability in 100 days. These results were consistent with the visual changes and FE-SEM images of the two biodegradable polymers after the landfill burial test, showing that only PCL-starch blend had various sized pinholes on the surface due to attack by microorganisms. This result may be use in deciding suitable final disposal approaches of different types of biodegradable polymers in the future. PMID:21144726

  18. BTEX biodegradation in fractured shale

    SciTech Connect

    O`Cleirigh, D.; Coryea, H.; Christopher, M.; Vaughn, C.

    1997-12-31

    A petroleum hydrocarbon groundwater plume was identified at a Federal Aviation Administration (FAA) facility in Oklahoma. The affected area had an average BTEX concentration of 3.8 mg/L. Previous aquifer tests indicated preferential groundwater flow paths resulting from natural fractures present in the aquifer formation (primarily shale). A pneumatic fracturing pilot study was performed to evaluate the technology`s effectiveness in creating a more isotropic aquifer. As part of the study, pre-fracture/post-fracture pump tests were performed. Pre-fracture and post-fracture graphs confirmed the study`s hypothesis that pneumatic fracturing would eliminate preferential flow paths and increase groundwater yield. Based on the successful pneumatic fracturing test, an area within the petroleum hydrocarbon plume was fractured and a pilot-scale biodegradation system was operated for four months. The remediation system provided groundwater circulation amended with nutrients and oxygen. Results of the study indicated a significant decrease in BTEX concentrations between the injection well and the observation wells. By Day 113, the benzene concentration (0.044 mg/L) at one of the observation wells was less than the desired state cleanup goal of 0.05 mg/L.

  19. Fungal biodegradation of pomegranate ellagitannins.

    PubMed

    Ascacio-Valdés, Juan A; Buenrostro, José J; De la Cruz, Reynaldo; Sepúlveda, Leonardo; Aguilera, Antonio F; Prado, Arely; Contreras, Juan C; Rodríguez, Raúl; Aguilar, Cristóbal N

    2014-01-01

    Ellagitannins (ETs) are phytochemicals derived from secondary metabolism associated to defense system, with complex chemical structures, which have high participation during all stages of protection against microbial infection. In this study, we report the fungal biodegradation of a bioactive ET, named punicaline which was recovered and purified from pomegranate peels and used as carbon source in solid-state culture (SSC) using polyurethane as solid support. SSC was kinetically monitored during 36 h of incubation time. ETs and glycosides consumption were spectrophotometrically determined. Ellagic acid (EA) accumulation was analyzed by HPLC. Several enzymatic activities were assayed (cellulase, xylanase, β-glucosydase, polyphenoloxidase, tannase, and ET hydrolyzing activities). The consumption levels of ETs and glycosides were 66 and 40%, while EA accumulation reached 42.02 mg g(-1). A differential pattern of enzymatic activities was found; evidence from our studies suggests that the ET hydrolyzing activity is directly associated to EA accumulation, and production of this enzyme may represent the most critical step to successfully develop a bioprocess for production of an important bioactive compound, the EA. PMID:23564673

  20. Hydrocarbon Biodegradation in Hypersaline Environments

    PubMed Central

    Ward, David M.; Brock, T. D.

    1978-01-01

    When mineral oil, hexadecane, and glutamate were added to natural samples of varying salinity (3.3 to 28.4%) from salt evaporation ponds and Great Salt Lake, Utah, rates of metabolism of these compounds decreased as salinity increased. Rate limitations did not appear to relate to low oxygen levels or to the availability of organic nutrients. Some oxidation of l-[U-14C]glutamic acid occurred even at extreme salinities, whereas oxidation of [1-14C]hexadecane was too low to be detected. Gas chromatographic examination of hexane-soluble components of tar samples from natural seeps at Rozel Point in Great Salt Lake demonstrated no evidence of biological oxidation of isoprenoid alkanes subject to degradation in normal environments. Some hexane-soluble components of the same tar were altered by incubation in a low-salinity enrichment culture inoculated with garden soil. Attempts to enrich for microorganisms in saline waters able to use mineral oil as a sole source of carbon and energy were successful below, but not above, about 20% salinity. This study strongly suggests a general reduction of metabolic rate at extreme salinities and raises doubt about the biodegradation of hydrocarbons in hypersaline environments. PMID:16345276

  1. Synthesis and Testing of the Insecticide Carbaryl: A Laboratory Experiment.

    ERIC Educational Resources Information Center

    Thadeo, Peter F.; Mowery, Dwight F.

    1984-01-01

    Carbaryl, 1-naphthyl-N-methylcarbamate, is the biodegradable (soft) insecticide most commonly marketed by the Union Carbide Corporation under the trade name of Sevin. Procedures for the synthesis and testing of carbaryl and for the testing of some compounds similar to carbaryl are provided. Equations showing its synthesis from methyl isocyanate…

  2. Biodegradable compounds: Rheological, mechanical and thermal properties

    NASA Astrophysics Data System (ADS)

    Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

    2015-12-01

    Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.

  3. PREDICTION OF BIODEGRADATION KINETICS USING A NONLINEAR GROUP CONTRIBUTION METHOD

    EPA Science Inventory

    The fate of organic chemicals in the environment depends on their susceptibility to biodegradation. ence, development of regulations concerning their manufacture and use requires information on the extent and rate of biodegradation. ecent studies have attempted to correlate the k...

  4. Evaluating the primary and ready biodegradability of dianilinodithiophosphoric acid.

    PubMed

    Lin, Weixiong; Sun, Shuiyu; Xu, Pingting; Dai, Yongkang; Ren, Jie

    2016-04-01

    Dianilinodithiophosphoric acid (DDA) is widely used as sulfide mineral flotation collector in China. It is necessary to investigate the biodegradability of DDA to provide the fundamental knowledge to assess the environmental fate in the risk assessment of DDA and to design and operate the DDA flotation wastewater biological treatment plant. In the present study, the primary and ready aerobic biodegradations of DDA were studied and the primary biodegradation kinetic model of DDA was developed. The results show that DDA displays a good primary biodegradability and its biodegradation ratio reaches 99.8 % in 7 days. In contrast, DDA is not easily ready biodegradable; hence, it is a partially biodegradable organic compound. The primary aerobic biodegradation kinetics can be described using the first-order reaction kinetics equation: C = 19.72191e(-0.01513t). PMID:27000317

  5. Introduction of Environmentally Degradable Parameters to Evaluate the Biodegradability of Biodegradable Polymers

    PubMed Central

    Yang, Chao; Song, Cunjiang; Geng, Weitao; Li, Qiang; Wang, Yuanyuan; Kong, Meimei; Wang, Shufang

    2012-01-01

    Environmentally Degradable Parameter (EdK) is of importance in the describing of biodegradability of environmentally biodegradable polymers (BDPs). In this study, a concept EdK was introduced. A test procedure of using the ISO 14852 method and detecting the evolved carbon dioxide as an analytical parameter was developed, and the calculated EdK was used as an indicator for the ultimate biodegradability of materials. Starch and polyethylene used as reference materials were defined as the EdK values of 100 and 0, respectively. Natural soil samples were inoculated into bioreactors, followed by determining the rates of biodegradation of the reference materials and 15 commercial BDPs over a 2-week test period. Finally, a formula was deduced to calculate the value of EdK for each material. The EdK values of the tested materials have a positive correlation to their biodegradation rates in the simulated soil environment, and they indicated the relative biodegradation rate of each material among all the tested materials. Therefore, the EdK was shown to be a reliable indicator for quantitatively evaluating the potential biodegradability of BDPs in the natural environment. PMID:22675455

  6. Imparting Superhydrophobicity to Biodegradable Poly(lactide-co-glycolide) Electrospun Meshes

    PubMed Central

    2015-01-01

    The synthesis of a family of new poly(lactic acid-co-glycerol monostearate) (PLA–PGC18) copolymers and their use as biodegradable polymer dopants is reported to enhance the hydrophobicity of poly(lactic acid-co-glycolic acid) (PLGA) nonwoven meshes. Solutions of PLGA are doped with PLA–PGC18 and electrospun to form meshes with micrometer-sized fibers. Fiber diameter, percent doping, and copolymer composition influence the nonwetting nature of the meshes and alter their mechanical (tensile) properties. Contact angles as high as 160° are obtained with 30% polymer dopant. Lastly, these meshes are nontoxic, as determined by an NIH/3T3 cell biocompatibility assay, and displayed a minimal foreign body response when implanted in mice. In summary, a general method for constructing biodegradable fibrous meshes with tunable hydrophobicity is described for use in tissue engineering and drug delivery applications. PMID:24901038

  7. Materials derived from biomass/biodegradable materials.

    PubMed

    Luzier, W D

    1992-02-01

    Interest in biodegradable plastics made from renewable resources has increased significantly in recent years. PHBV (polyhydroxybutyrate-polyhydroxyvalerate) copolymers are good examples of this type of materials. This paper provides an overview of the manufacturing process, properties, biodegradability, and application/commercial issues associated with PHBV copolymers. They are naturally produced by bacteria from agricultural raw materials, and they can be processed to make a variety of useful products, where their biodegradability and naturalness are quite beneficial. PHBV copolymers are still in the first stage of commercialization. But they are presented in this paper as an example of how new technology can help meet society's needs for plastics and a clean environment. PMID:1736301

  8. Aerobic biodegradation of trichloroethene without auxiliary substrates.

    PubMed

    Schmidt, Kathrin R; Gaza, Sarah; Voropaev, Andrey; Ertl, Siegmund; Tiehm, Andreas

    2014-08-01

    Trichloroethene (TCE) represents a priority pollutant and is among the most frequently detected contaminants in groundwater. The current bioremediation measures have certain drawbacks like e.g. the need for auxiliary substrates. Here, the aerobic biodegradation of TCE as the sole growth substrate is demonstrated. This new process of metabolic TCE degradation was first detected in groundwater samples. TCE degradation was stable in an enriched mixed bacterial culture in mineral salts medium for over five years and repeated transfers of the culture resulting in a 10(10) times dilution of the original groundwater. Aerobic TCE degradation resulted in stoichiometric chloride formation. Stable carbon isotope fractionation was observed providing a reliable analytical tool to assess this new biodegradation process at field sites. The results suggest that aerobic biodegradation of TCE without auxiliary substrate could be considered as an option for natural attenuation or engineered bioremediation of contaminated sites. PMID:24793109

  9. Biodegradable Polymers and Stem Cells for Bioprinting.

    PubMed

    Lei, Meijuan; Wang, Xiaohong

    2016-01-01

    It is imperative to develop organ manufacturing technologies based on the high organ failure mortality and serious donor shortage problems. As an emerging and promising technology, bioprinting has attracted more and more attention with its super precision, easy reproduction, fast manipulation and advantages in many hot research areas, such as tissue engineering, organ manufacturing, and drug screening. Basically, bioprinting technology consists of inkjet bioprinting, laser-based bioprinting and extrusion-based bioprinting techniques. Biodegradable polymers and stem cells are common printing inks. In the printed constructs, biodegradable polymers are usually used as support scaffolds, while stem cells can be engaged to differentiate into different cell/tissue types. The integration of biodegradable polymers and stem cells with the bioprinting techniques has provided huge opportunities for modern science and technologies, including tissue repair, organ transplantation and energy metabolism. PMID:27136526

  10. Biodegradable containers from green waste materials

    NASA Astrophysics Data System (ADS)

    Sartore, Luciana; Schettini, Evelia; Pandini, Stefano; Bignotti, Fabio; Vox, Giuliano; D'Amore, Alberto

    2016-05-01

    Novel biodegradable polymeric materials based on protein hydrolysate (PH), derived from waste products of the leather industry, and poly(ethylene glycol) diglycidyl ether (PEG) or epoxidized soybean oil (ESO) were obtained and their physico-chemical properties and mechanical behaviour were evaluated. Different processing conditions and the introduction of fillers of natural origin, as saw dust and wood flour, were used to tailor the mechanical properties and the environmental durability of the product. The biodegradable products, which are almost completely manufactured from renewable-based raw materials, look promising for several applications, particularly in agriculture for the additional fertilizing action of PH or in packaging.

  11. Comparative study on the biodegradation and biocompatibility of silicate bioceramic coatings on biodegradable magnesium alloy as biodegradable biomaterial

    NASA Astrophysics Data System (ADS)

    Razavi, M.; Fathi, M. H.; Savabi, O.; Razavi, S. M.; Hashemibeni, B.; Yazdimamaghani, M.; Vashaee, D.; Tayebi, L.

    2014-03-01

    Many clinical cases as well as in vivo and in vitro assessments have demonstrated that magnesium alloys possess good biocompatibility. Unfortunately, magnesium and its alloys degrade too quickly in physiological media. In order to improve the biodegradation resistance and biocompatibility of a biodegradable magnesium alloy, we have prepared three types of coating include diopside (CaMgSi2O6), akermanite (Ca2MgSi2O6) and bredigite (Ca7MgSi4O16) coating on AZ91 magnesium alloy through a micro-arc oxidation (MAO) and electrophoretic deposition (EPD) method. In this research, the biodegradation and biocompatibility behavior of samples were evaluated in vitro and in vivo. The in vitro analysis was performed by cytocompatibility and MTT-assay and the in vivo test was conducted on the implantation of samples in the greater trochanter of adult rabbits. The results showed that diopside coating has the best bone regeneration and bredigite has the best biodegradation resistance compared to others.

  12. Stability of biodegradable waterborne polyurethane films in buffered saline solutions.

    PubMed

    Lin, Ying Yi; Hung, Kun-Che; Hsu, Shan-Hui

    2015-01-01

    The stability of polyurethane (PU) is of critical importance for applications such as in coating industry or as biomaterials. To eliminate the environmental concerns on the synthesis of PU which involves the use of organic solvents, the aqueous-based or waterborne PU (WBPU) has been developed. WBPU, however, may be unstable in an electrolyte-rich environment. In this study, the authors reported the stability of biodegradable WBPU in the buffered saline solutions evaluated by atomic force microscopy (AFM). Various biodegradable WBPU films were prepared by spin coating on coverslip glass, with a thickness of ∼300 nm. The surface AFM images of poly(ε-caprolactone) (PCL) diol-based WBPU revealed nanoglobular structure. The same feature was observed when 20% molar of the PCL diol soft segment was replaced by polyethylene butylenes adipate diol. After hydration in buffered saline solutions for 24 h, the surface domains generally increased in sizes and became irregular in shape. On the other hand, when the soft segment was replaced by 20% poly(l-lactide) diol, a meshlike surface structure was demonstrated by AFM. When the latter WBPU was hydrated, the surface domains appeared to be disconnected. Results from the attenuated total reflectance infrared spectroscopy and x-ray photoelectron spectroscopy indicated that the surface chemistry of WBPU films was altered after hydration. These changes were probably associated with the neutralization of carboxylate by ions in the saline solutions, resulting in the rearrangements of soft and hard segments and causing instability of the WBPU. PMID:26296357

  13. RESPIROMETRIC METHODS FOR DETERMINATION OF BIODEGRADABILITY AND BIODEGRADATION KINETICS FOR HAZARDOUS ORGANIC POLLUTANT COMPOUNDS

    EPA Science Inventory

    Electrolytic respirometry involving natural sewage, sludge and soil microbiota is becoming prominent in fate studies of priority pollutant and RCRA toxic organics to generate biodegradation/inhibition kinetic data. eveloped multi-level protocol is presented for determination of s...

  14. Phyllosphere yeasts rapidly break down biodegradable plastics.

    PubMed

    Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-Hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

    2011-01-01

    The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands. PMID:22126328

  15. Biodegradability of leathers through anaerobic pathway.

    PubMed

    Dhayalan, K; Fathima, N Nishad; Gnanamani, A; Rao, J Raghava; Nair, B Unni; Ramasami, T

    2007-01-01

    Leather processing generates huge amounts of both solid and liquid wastes. The management of solid wastes, especially tanned leather waste, is a challenging problem faced by tanners. Hence, studies on biodegradability of leather become imperative. In this present work, biodegradability of untanned, chrome tanned and vegetable tanned leather under anaerobic conditions has been addressed. Two different sources of anaerobes have been used for this purpose. The effect of detanning as a pretreatment method before subjecting the leather to biodegradation has also been studied. It has been found that vegetable tanned leather leads to more gas production than chrome tanned leather. Mixed anaerobic isolates when employed as an inoculum are able to degrade the soluble organics of vegetable tanned material and thus exhibit an increased level of gas production during the initial days, compared to the results of the treatments that received the anaerobic sludge. With chrome tanned materials, there was not much change in the volume of the gas produced from the two different sources. It has been found that detanning tends to improve the biodegradability of both types of leathers. PMID:16740383

  16. Current trends in trichloroethylene biodegradation: a review.

    PubMed

    Shukla, Awadhesh Kumar; Upadhyay, Siddh Nath; Dubey, Suresh Kumar

    2014-06-01

    Over the past few years biodegradation of trichloroethylene (TCE) using different microorganisms has been investigated by several researchers. In this review article, an attempt has been made to present a critical summary of the recent results related to two major processes--reductive dechlorination and aerobic co-metabolism used for TCE biodegradation. It has been shown that mainly Clostridium sp. DC-1, KYT-1, Dehalobacter, Dehalococcoides, Desulfuromonas, Desulfitobacterium, Propionibacterium sp. HK-1, and Sulfurospirillum bacterial communities are responsible for the reductive dechlorination of TCE. Efficacy of bacterial communities like Nitrosomonas, Pseudomonas, Rhodococcus, and Xanthobacter sp. etc. for TCE biodegradation under aerobic conditions has also been examined. Mixed cultures of diazotrophs and methanotrophs have been used for TCE degradation in batch and continuous cultures (biofilter) under aerobic conditions. In addition, some fungi (Trametes versicolor, Phanerochaete chrysosporium ME-446) and Actinomycetes have also been used for aerobic biodegradation of TCE. The available information on kinetics of biofiltration of TCE and its degradation end-products such as CO2 are discussed along with the available results on the diversity of bacterial community obtained using molecular biological approaches. It has emerged that there is a need to use metabolic engineering and molecular biological tools more intensively to improve the robustness of TCE degrading microbial species and assess their diversity. PMID:23057686

  17. DEMONSTRATION BULLETIN: SLURRY BIODEGRADATION, International Technology Corporation

    EPA Science Inventory

    This technology uses a slurry-phase bioreactor in which the soil is mixed with water to form a slurry. Microorganisms and nutrients are added to the slurry to enhance the biodegradation process, which converts organic wastes into relatively harmless byproducts of microbial metabo...

  18. ENGINEERING BULLETIN: IN SITU BIODEGRADATION TREATMENT

    EPA Science Inventory

    In situ biodegradation may be used to treat low-to-intermediate concentrations of organic contaminants in place without disturbing or displacing the contaminated media. Although this technology has been used to degrade a limited number of inorganics, specifically cyanide and nitr...

  19. Phyllosphere yeasts rapidly break down biodegradable plastics

    PubMed Central

    2011-01-01

    The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands. PMID:22126328

  20. Biodegradation Of thermoplastic polyurethanes from vegetable oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermoplastic urethanes based on polyricinoleic acid soft segments and MDI/BD hard segments with varied soft segment concentration were prepared. Soft segment concentration was varied fro, 40 to 70 wt %. Biodegradation was studied by respirometry. Segmented polyurethanes with soft segments based ...

  1. APPLICATIONS FOR DNA PROBES IN BIODEGRADATION RESEARCH

    EPA Science Inventory

    The use of DNA:DNA hybridization technology in biodegradation studies is investigated. The rate constants for sediments exposed to synthetic oils could be calculated from the NAH(1+) genotypes and this approach would be useful in predicting the kinetics of aromatic hydrocarbon de...

  2. BIODEGRADATION OF ATRAZINE IN SUBSURFACE ENVIRONMENTS

    EPA Science Inventory

    The pesticide atrazine is frequently detected in ground water, including ground water used as drinking water. Little information is available on the fate of atrazine in the subsurface, including its biodegradability. The objectives of this study were to evaluate the biodegradabil...

  3. Does Bioavailability Limit Biodegradability? A Comparison of Hydrocarbon Biodegradation and Desorption Rates in Aged Soils

    SciTech Connect

    Huesemann, Michael H.; Hausmann, Tom S.; Fortman, Timothy J.

    2004-08-01

    In order to determine whether bioavailability limits the biodegradability of petroleum hydrocarbons in aged soils, both the biodegradation and abiotic desorption rates of PAHs and n-alkanes were measured at various time points in six different aged soils undergoing slurry bioremediation treatment. Alkane biodegradation rates were always much greater than the respective desorption rates, indicating that these saturated hydrocarbons do not need to be transferred into the aqueous phase prior to metabolism by soil microorganisms. The biodegradation of PAHs was generally not mass-transfer rate limited during the initial phase, while it often became so at the end of the treatment period when biodegradation rates equaled abiotic desorption rates. However, in all cases where PAH biodegradation was not observed or PAH removal temporarily stalled, bioavailability limitations were not deemed responsible for this recalcitrance since these PAHs desorbed rapidly from the soil into the aqueous phase. Consequently, aged PAHs that are often thought to be recalcitrant due to bioavailability limitations may not be so and therefore may pose a greater risk to environmental receptors than previously thought.

  4. In vitro biodegradation behavior, mechanical properties, and cytotoxicity of biodegradable Zn-Mg alloy.

    PubMed

    Gong, Haibo; Wang, Kun; Strich, Randy; Zhou, Jack G

    2015-11-01

    Zinc-Magnesium (Zn-Mg) alloy as a novel biodegradable metal holds great potential in biodegradable implant applications as it is more corrosion resistant than Magnesium (Mg). However, the mechanical properties, biodegradation uniformity, and cytotoxicity of Zn-Mg alloy remained as concerns. In this study, hot extrusion process was applied to Zn-1 wt % Mg (Zn-1Mg) to refine its microstructure. Effects of hot extrusion on biodegradation behavior and mechanical properties of Zn-1Mg were investigated in comparison with Mg rare earth element alloy WE43. Metallurgical analysis revealed significant grain size reduction, and immersion test found that corrosion rates of WE43 and Zn-1Mg were reduced by 35% and 57%, respectively after extrusion. Moreover, hot extrusion resulted in a much more uniform biodegradation in extruded Zn-1Mg alloy and WE43. In vitro cytotoxicity test results indicated that Zn-1Mg alloy was biocompatible. Therefore, hot extruded Zn-1Mg with homogenous microstructure, uniform as well as slow degradation, improved mechanical properties, and good biocompatibility was believed to be an excellent candidate material for load-bearing biodegradable implant application. PMID:25581552

  5. Carbon and Hydrogen Isotopic Fractionation during Anaerobic Biodegradation of Benzene

    PubMed Central

    Mancini, Silvia A.; Ulrich, Ania C.; Lacrampe-Couloume, Georges; Sleep, Brent; Edwards, Elizabeth A.; Sherwood Lollar, Barbara

    2003-01-01

    Compound-specific isotope analysis has the potential to distinguish physical from biological attenuation processes in the subsurface. In this study, carbon and hydrogen isotopic fractionation effects during biodegradation of benzene under anaerobic conditions with different terminal-electron-accepting processes are reported for the first time. Different enrichment factors (ɛ) for carbon (range of −1.9 to −3.6‰) and hydrogen (range of −29 to −79‰) fractionation were observed during biodegradation of benzene under nitrate-reducing, sulfate-reducing, and methanogenic conditions. These differences are not related to differences in initial biomass or in rates of biodegradation. Carbon isotopic enrichment factors for anaerobic benzene biodegradation in this study are comparable to those previously published for aerobic benzene biodegradation. In contrast, hydrogen enrichment factors determined for anaerobic benzene biodegradation are significantly larger than those previously published for benzene biodegradation under aerobic conditions. A fundamental difference in the previously proposed initial step of aerobic versus proposed anaerobic biodegradation pathways may account for these differences in hydrogen isotopic fractionation. Potentially, C-H bond breakage in the initial step of the anaerobic benzene biodegradation pathway may account for the large fractionation observed compared to that in aerobic benzene biodegradation. Despite some differences in reported enrichment factors between cultures with different terminal-electron-accepting processes, carbon and hydrogen isotope analysis has the potential to provide direct evidence of anaerobic biodegradation of benzene in the field. PMID:12513995

  6. Biodegradation of acetanilide herbicides acetochlor and butachlor in soil.

    PubMed

    Ye, Chang-ming; Wang, Xing-jun; Zheng, He-hui

    2002-10-01

    The biodegradation of two acetanilide herbicides, acetochlor and butachlor in soil after other environmental organic matter addition were measured during 35 days laboratory incubations. The herbicides were applied to soil alone, soil-SDBS (sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid) mixtures. Herbicide biodegradation kinetics were compared in the different treatment. Biodegradation products of herbicides in soil alone samples were identified by GC/MS at the end of incubation. Addition of SDBS and HA to soil decreased acetochlor biodegradation, but increased butachlor biodegradation. The biodegradation half-life of acetochlor and butachlor in soil alone, soil-SDBS mixtures and soil-HA mixtures were 4.6 d, 6.1 d and 5.4 d and 5.3 d, 4.9 d and 5.3 d respectively. The biodegradation products were hydroxyacetochlor and 2-methyl-6-ethylaniline for acetochlor, and hydroxybutachlor and 2,6-diethylaniline for butachlor. PMID:12491727

  7. Improving the biodegradative capacity of subsurface bacteria

    SciTech Connect

    Romine, M.F.; Brockman, F.J.

    1993-04-01

    The continual release of large volumes of synthetic materials into the environment by agricultural and industrial sources over the last few decades has resulted in pollution of the subsurface environment. Cleanup has been difficult because of the relative inaccessibility of the contaminants caused by their wide dispersal in the deep subsurface, often at low concentrations and in large volumes. As a possible solution for these problems, interest in the introduction of biodegradative bacteria for in situ remediation of these sites has increased greatly in recent years (Timmis et al. 1988). Selection of biodegradative microbes to apply in such cleanup is limited to those strains that can survive among the native bacterial and predator community members at the particular pH, temperature, and moisture status of the site (Alexander, 1984). The use of microorganisms isolated from subsurface environments would be advantageous because the organisms are already adapted to the subsurface conditions. The options are further narrowed to strains that are able to degrade the contaminant rapidly, even in the presence of highly recalcitrant anthropogenic waste mixtures, and in conditions that do not require addition of further toxic compounds for the expression of the biodegradative capacity (Sayler et al. 1990). These obstacles can be overcome by placing the genes of well-characterized biodegradative enzymes under the control of promoters that can be regulated by inexpensive and nontoxic external factors and then moving the new genetic constructs into diverse groups of subsurface microbes. ne objective of this research is to test this hypothesis by comparing expression of two different toluene biodegradative enzymatic pathways from two different regulatable promoters in a variety of subsurface isolates.

  8. Enhancement of polyether biodegradation in activated sludge

    SciTech Connect

    Christopher, L.J.

    1993-01-01

    Previous studies in this laboratory showed that pretreatment with Petroleum Chemical Extinguisher[reg sign] (PCE), a C[sub 18] unsaturated fatty acid diester of polyethylene glycol (PEG), enhanced the biodegradation of PEG 1,000 and PEG 1,450 in soil. In this study the ability of PCE and other PEG-fatty acid diesters to enhance biodegradation of PEGs in activated sludge was investigated. Additionally, polyether-fatty acid esters similar to PCE were synthesized and tested to determine how they affected biodegradation of PEGs and other polyethers. Attempts were made to understand the mechanism for enhancement of biodegradation. Carbon-dioxide evolution and thin-layer chromatographic analysis indicated degradation of PEG 1,000, PEG 1,450, and PEG 3,350 in sludge samples which were previously exposed to PCE. Those samples which were not pre-treated with PCE showed no detectable PEG degradation during the two-week study. Preexposure to PCE did not enhance subsequent degradation of PEG 8,000, nor polypropylene glycol (PPG) 1,025. However, pretreatment of sludge with a PPG 1,025-di oleic acid ester promoted PPG 1,205 degradation. Interestingly, microbial populations do not seem to be gaining much biomass or energy from the degradation of PEG-di fatty acid esters or PEGs. When PCE-pretreated sludge samples were given [sup 14]C-PEG 3,350 as substrate, evolution of [sup 14]CO[sub 2] occurred and little (<5%) of the [sup 14]C was assimilated by the microorganisms in the sludge. Futhermore, determinations of ATP content and esterase activity of sludge samples suggested that there was not a substantial increase in biomass as a result of degradation of either PCE or PEGs. PCE preexposure effected an increase in PEG dehydrogenase activity. This increase may be due to induction of enzymes responsible for PEG biodegradation or selection for organisms in the microbial population which are PEG degraders.

  9. BTEX biodegradation by bacteria from effluents of petroleum refinery.

    PubMed

    Mazzeo, Dânia Elisa Christofoletti; Levy, Carlos Emílio; de Angelis, Dejanira de Franceschi; Marin-Morales, Maria Aparecida

    2010-09-15

    Groundwater contamination with benzene, toluene, ethylbenzene and xylene (BTEX) has been increasing, thus requiring an urgent development of methodologies that are able to remove or minimize the damages these compounds can cause to the environment. The biodegradation process using microorganisms has been regarded as an efficient technology to treat places contaminated with hydrocarbons, since they are able to biotransform and/or biodegrade target pollutants. To prove the efficiency of this process, besides chemical analysis, the use of biological assessments has been indicated. This work identified and selected BTEX-biodegrading microorganisms present in effluents from petroleum refinery, and evaluated the efficiency of microorganism biodegradation process for reducing genotoxic and mutagenic BTEX damage through two test-systems: Allium cepa and hepatoma tissue culture (HTC) cells. Five different non-biodegraded BTEX concentrations were evaluated in relation to biodegraded concentrations. The biodegradation process was performed in a BOD Trak Apparatus (HACH) for 20 days, using microorganisms pre-selected through enrichment. Although the biodegradation usually occurs by a consortium of different microorganisms, the consortium in this study was composed exclusively of five bacteria species and the bacteria Pseudomonas putida was held responsible for the BTEX biodegradation. The chemical analyses showed that BTEX was reduced in the biodegraded concentrations. The results obtained with genotoxicity assays, carried out with both A. cepa and HTC cells, showed that the biodegradation process was able to decrease the genotoxic damages of BTEX. By mutagenic tests, we observed a decrease in damage only to the A. cepa organism. Although no decrease in mutagenicity was observed for HTC cells, no increase of this effect after the biodegradation process was observed either. The application of pre-selected bacteria in biodegradation processes can represent a reliable and

  10. Cationic gemini surfactants with cleavable spacer: chemical hydrolysis, biodegradation, and toxicity.

    PubMed

    Tehrani-Bagha, A R; Holmberg, K; van Ginkel, C G; Kean, M

    2015-07-01

    The paper describes synthesis and characterization of a new type of cationic gemini surfactant, which has dodecyl tails and a spacer that contains an ester bond. The nomenclature used to describe the structure is 12Q2OCO1Q12, with Q being a quaternary ammonium group and the numbers indicating the number of methylene or methyl groups. Due to the close proximity to the two quaternary ammonium groups, the ester bond is very stable on the acid side and very labile already at slightly alkaline conditions. The hydrolysis products are two single chain surfactants (i.e. 12Q2OH and 12Q1COOH) which are less surface active than the intact gemini surfactant. 12Q2OCO1Q12 was found to be readily biodegradable, i.e. it gave more than 60% biodegradation after 28 days. This is interesting because similar gemini surfactants but with ester bonds in the tails instead of the spacer, have previously been found not to be readily biodegradable. The gemini surfactant was found to be toxic to aquatic organisms (ErC50 value of 0.27 mg/l), although less toxic than the two hydrolysis products. PMID:25446957

  11. Biodegradation test of SPS-LS blends as polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Putri, Zufira; Arcana, I. Made

    2014-03-01

    Sulfonated polystyrene (SPS) can be applied as a proton exchange membrane fuel cell due to its fairly good chemical stability. In order to be applied as polymer electrolyte membrane fuel cells (PEMFCs), membrane polymer should have a good ionic conductivity, high proton conductivity, and high mechanical strength. Lignosulfonate (LS) is a complex biopolymer which has crosslinks and sulfonate groups. SPS-LS blends with addition of SiO2 are used to increase the proton conductivity and to improve the mechanical properties and thermal stability. However, the biodegradation test of SPS-LS blends is required to determine whether the application of these membranes to be applied as an environmentally friendly membrane. In this study, had been done the synthesis of SPS, biodegradability test of SPS-LS blends with variations of LS and SiO2 compositions. The biodegradation test was carried out in solid medium of Luria Bertani (LB) with an activated sludge used as a source of microorganism at incubation temperature of 37°C. Based on the results obtained indicated that SPS-LS-SiO2 blends are more decomposed by microorganism than SPS-LS blends. This result is supported by analysis of weight reduction percentage, functional groups with Fourier Transform Infrared (FTIR) Spectroscopy, and morphological surface with Scanning Electron Microscopy (SEM).

  12. Biodegradation test of SPS-LS blends as polymer electrolyte membrane fuel cells

    SciTech Connect

    Putri, Zufira E-mail: arcana@chem.itb.ac.id; Arcana, I Made E-mail: arcana@chem.itb.ac.id

    2014-03-24

    Sulfonated polystyrene (SPS) can be applied as a proton exchange membrane fuel cell due to its fairly good chemical stability. In order to be applied as polymer electrolyte membrane fuel cells (PEMFCs), membrane polymer should have a good ionic conductivity, high proton conductivity, and high mechanical strength. Lignosulfonate (LS) is a complex biopolymer which has crosslinks and sulfonate groups. SPS-LS blends with addition of SiO{sub 2} are used to increase the proton conductivity and to improve the mechanical properties and thermal stability. However, the biodegradation test of SPS-LS blends is required to determine whether the application of these membranes to be applied as an environmentally friendly membrane. In this study, had been done the synthesis of SPS, biodegradability test of SPS-LS blends with variations of LS and SiO{sub 2} compositions. The biodegradation test was carried out in solid medium of Luria Bertani (LB) with an activated sludge used as a source of microorganism at incubation temperature of 37°C. Based on the results obtained indicated that SPS-LS-SiO{sub 2} blends are more decomposed by microorganism than SPS-LS blends. This result is supported by analysis of weight reduction percentage, functional groups with Fourier Transform Infrared (FTIR) Spectroscopy, and morphological surface with Scanning Electron Microscopy (SEM)

  13. Assessing the role of Pseudomonas aeruginosa surface-active gene expression in hexadecane biodegradation in sand.

    PubMed

    Holden, P A; LaMontagne, M G; Bruce, A K; Miller, W G; Lindow, S E

    2002-05-01

    Low pollutant substrate bioavailability limits hydrocarbon biodegradation in soils. Bacterially produced surface-active compounds, such as rhamnolipid biosurfactant and the PA bioemulsifying protein produced by Pseudomonas aeruginosa, can improve bioavailability and biodegradation in liquid culture, but their production and roles in soils are unknown. In this study, we asked if the genes for surface-active compounds are expressed in unsaturated porous media contaminated with hexadecane. Furthermore, if expression does occur, is biodegradation enhanced? To detect expression of genes for surface-active compounds, we fused the gfp reporter gene either to the promoter region of pra, which encodes for the emulsifying PA protein, or to the promoter of the transcriptional activator rhlR. We assessed green fluorescent protein (GFP) production conferred by these gene fusions in P. aeruginosa PG201. GFP was produced in sand culture, indicating that the rhlR and pra genes are both transcribed in unsaturated porous media. Confocal laser scanning microscopy of liquid drops revealed that gfp expression was localized at the hexadecane-water interface. Wild-type PG201 and its mutants that are deficient in either PA protein, rhamnolipid synthesis, or both were studied to determine if the genetic potential to make surface-active compounds confers an advantage to P. aeruginosa biodegrading hexadecane in sand. Hexadecane depletion rates and carbon utilization efficiency in sand culture were the same for wild-type and mutant strains, i.e., whether PG201 was proficient or deficient in surfactant or emulsifier production. Environmental scanning electron microscopy revealed that colonization of sand grains was sparse, with cells in small monolayer clusters instead of multilayered biofilms. Our findings suggest that P. aeruginosa likely produces surface-active compounds in sand culture. However, the ability to produce surface-active compounds did not enhance biodegradation in sand culture

  14. Visualization experiments of biodegradation in porous media and calculation of the biodegradation rate

    NASA Astrophysics Data System (ADS)

    Vayenas, D. V.; Michalopoulou, E.; Constantinides, G. N.; Pavlou, S.; Payatakes, A. C.

    Biodegradation in porous media is studied with carefully controlled and well-characterized experiments in model porous media constructed of etched glass. Porous media of this type allow visual observation of the phenomena that take place at pore scale. An aqueous solution of five organic pollutants (toluene, phenol, o-cresol, naphthalene and 1,2,3-trimethylbenzene) was used as a model NAPL (representing creosote). The bacteria used were Pseudomonas fluorescens, which are indigenous (even predominant) in many contaminated soils. The maximum aqueous concentrations of the specific organic substances, below which biodegradation becomes possible, were determined as a function of temperature from toxicity experiments. Visualization experiments were made under various flow velocities and organic loadings to study the morphology and thickness of the biofilm as a function of the pore size and the distance from the entrance, and the efficiency of biodegradation. The efficiency of biodegradation decreased as the aqueous concentration of NAPL at the inlet increased and/or as the flow velocity increased. The thickness of biofilm decreased as the distance from the inlet increased and/or the pore diameter decreased. A quasi-steady-state theoretical model of biodegradation was used to calculate the values of the mesoscopic biochemical rates and to predict the profile of NAPL concentration in the porous medium and the thickness of biofilm in pores. The agreement between experimental data and model predictions is quite satisfactory.

  15. Enhanced biodegradation resistance of biomodified jute fibers.

    PubMed

    Manna, Suvendu; Saha, Prosenjit; Roy, Debasis; Sen, Ramkrishna; Adhikari, Basudam; Das, Sancharini

    2013-04-01

    A bio-catalyzed process has been developed for treating jute fibers to enhance their tensile strength and resistance against biodegradation. Lipolytic bacteria were used in the process to transesterify jute fibers by replacing hydrophilic hydroxyl groups within cellulose chains with hydrophobic fatty acyl chains. Transesterification of some of the hydroxyl groups within the fiber was confirmed with FTIR, UV-vis spectroscopy, (13)C solid state NMR, gas chromatography and analytical determination of ester content. Biomodified fibers exhibited remarkably smaller affinity to water and moisture and retained 62% of their initial tensile strengths after being exposed to a composting environment over 21 days. The corresponding figure for untreated fibers was only 30%. Efficacy of the process reported herein in terms of tensile strength and biodegradation resistance enhancement of fibers achieved after treatment appears to be comparable with similar chemical processes and better than the enzyme-catalyzed alternatives. PMID:23499101

  16. New Routes for Aerobic Biodegradation of Dimethylsulfoniopropionate

    PubMed Central

    Taylor, Barrie F.; Gilchrist, Darrin C.

    1991-01-01

    Dimethylsulfoniopropionate (DMSP), an osmolyte in marine plants, is biodegraded by cleavage of dimethyl sulfide (DMS) or by demethylation to 3-methiolpropionate (MMPA) and 3-mercaptopropionate (MPA). Sequential demethylation has been observed only with anoxic slurries of coastal sediments. Bacteria that grew aerobically on MMPA and DMSP were isolated from marine environments and phytoplankton cultures. Enrichments with DMSP selected for bacteria that generated DMS, whereas MMPA enrichments selected organisms that produced methanethiol (CH3SH) from either DMSP or MMPA. A bacterium isolated on MMPA grew on MMPA and DMSP, but rapid production of CH3SH from DMSP occurred only with DMSP-grown cells. Low levels of MPA accumulated during growth on MMPA, indicating demethylation as well as demethiolation of MMPA. The alternative routes for DMSP biodegradation via MMPA probably impact on net DMS fluxes to the marine atmosphere. PMID:16348607

  17. Study of biodegradable polymers for ``green'' devices

    NASA Astrophysics Data System (ADS)

    Perez, Carlos; Jiang, Xiaomei; Jiang Group Team

    2015-03-01

    Π - conjugated polymers such as polythiophenes are conventional picks for cost-effective organic solar cells. However, these organic semiconductors are not environment-friendly since the polymer back bones require temperature higher than 3000C to be decomposed, thus will cause potential environment problems upon disposal. In this work, the optical and electronic properties of biodegradable polymers, conjugated poly(disulfidediamine), were examined via continuous wave laser spectroscopy, FTIR spectroscopy and conductivity measurement. We found that the attachment of a side chain to aromatic ring increases both photo and thermal stability, as well as higher conductivity. Thermal annealing improved the film morphological, photophysical and electronic properties. Photo-Induced Absorption (PIA) reveals different features comparing with conventional pi-conjugated polymers. No observation of long-lived photoexcitations such as polarons or triplets which are common with pi-conjugated polymers. Instead, we found the formation of low energy species upon thermal annealing in these biodegradable polymers.

  18. Titanate nanotube coatings on biodegradable photopolymer scaffolds.

    PubMed

    Beke, S; Kőrösi, L; Scarpellini, A; Anjum, F; Brandi, F

    2013-05-01

    Rigid, biodegradable photopolymer scaffolds were coated with titanate nanotubes (TNTs) by using a spin-coating method. TNTs were synthesized by a hydrothermal process at 150 °C under 4.7 bar ambient pressure. The biodegradable photopolymer scaffolds were produced by mask-assisted excimer laser photocuring at 308 nm. For scaffold coating, a stable ethanolic TNT sol was prepared by a simple colloid chemical route without the use of any binding compounds or additives. Scanning electron microscopy along with elemental analysis revealed that the scaffolds were homogenously coated by TNTs. The developed TNT coating can further improve the surface geometry of fabricated scaffolds, and therefore it can further increase the cell adhesion. PMID:23498284

  19. Controlled morphology of biodegradable polymer blends

    NASA Astrophysics Data System (ADS)

    Buddhiranon, Sasiwimon; Kyu, Thein

    2009-03-01

    Phase diagrams of biodegradable polymer blends containing poly(ɛ-caprolactone) (PCL) and poly(d,l-lactic acid) (PDLLA) having two different molecular weights were established by means of cloud point measurement and differential scanning calorimetry. Subsequently, the theoretical phase diagram was calculated self-consistently based on the combination of Flory-Huggins free energy for liquid-liquid phase separation and phase field free energy for crystal solidification. The phase diagrams thus obtained were LCST type or hour-glass type, which depended on molecular weight of PDLLA utilized. Guided by the phase diagram, the emerged morphology was determined as a function of blend concentration and temperature. It appears that the morphology control is feasible that ultimately affects the end-use property of PCL/PDLLA blends. A wide variety of morphology of biodegradable polymer may be developed with the porous structure and pore size to control scaffold porosity and the rate of drug delivery.

  20. Modeling ready biodegradability of fragrance materials.

    PubMed

    Ceriani, Lidia; Papa, Ester; Kovarich, Simona; Boethling, Robert; Gramatica, Paola

    2015-06-01

    In the present study, quantitative structure activity relationships were developed for predicting ready biodegradability of approximately 200 heterogeneous fragrance materials. Two classification methods, classification and regression tree (CART) and k-nearest neighbors (kNN), were applied to perform the modeling. The models were validated with multiple external prediction sets, and the structural applicability domain was verified by the leverage approach. The best models had good sensitivity (internal ≥80%; external ≥68%), specificity (internal ≥80%; external 73%), and overall accuracy (≥75%). Results from the comparison with BIOWIN global models, based on group contribution method, show that specific models developed in the present study perform better in prediction than BIOWIN6, in particular for the correct classification of not readily biodegradable fragrance materials. PMID:25663647

  1. Biodegradable inflatable balloons for tissue separation.

    PubMed

    Basu, Arijit; Haim-Zada, Moran; Domb, Abraham J

    2016-10-01

    Confining radiation to a specific region (during radiation therapy) minimizes damage to surrounding tissues. Biodegradable inflatable balloons (bio-balloons) were developed. The device protects the normal tissues by increasing the gap between radiation source and critical structures. The radiation fades away while passing through the inflated balloon preventing the surrounding tissues from harmful radiation. These bio-balloons have also found clinical use to treat massive rotator cuff tear. This review summarizes the chemistry, engineering, and clinical development of these biomedical devices. These balloons are made of biodegradable polymers folded into the edge of a trocar and inserted between the tissues to be separated, and inflated by normal saline in the site of the application. The inserted balloon protects the tissues from radiation or mechanical stress. They remain inflated on site for two months and are finally eliminated within 12 months. PMID:27521613

  2. Anaerobic biodegradation of surrogate naphthenic acids.

    PubMed

    Clothier, Lindsay N; Gieg, Lisa M

    2016-03-01

    Surface bitumen extraction from the Alberta's oil sands region generates large settling basins known as tailings ponds. The oil sands process-affected water (OSPW) stored in these ponds contain solid and residual bitumen-associated compounds including naphthenic acids (NAs) that can potentially be biodedgraded by indigenous tailings microorganisms. While the biodegradation of some NAs is known to occur under aerobic conditions, little is understood about anaerobic NA biodegradation even though tailings ponds are mainly anoxic. Here, we investigated the potential for anaerobic NA biodegradation by indigenous tailings microorganisms. Enrichment cultures were established from anoxic tailings that were amended with 5 single-ringed surrogate NAs or acid-extractable organics (AEO) from OSPW and incubated under nitrate-, sulfate-, iron-reducing, and methanogenic conditions. Surrogate NA depletion was observed under all anaerobic conditions tested to varying extents, correlating to losses in the respective electron acceptor (sulfate or nitrate) or the production of predicted products (Fe(II) or methane). Tailings-containing cultures incubated under the different electron-accepting conditions resulted in the enrichment and putative identification of microbial community members that may function in metabolizing surrogate NAs under the various anoxic conditions. In addition, more complex NAs (in the form of AEO) was observed to drive sulfate and iron reduction relative to controls. Overall, this study has shown that simple surrogate NAs can be biodegraded under a variety of anoxic conditions, a key first step in understanding the potential anaerobic metabolism of NAs in oil sands tailings ponds and other industrial wastewaters. PMID:26724449

  3. Systematic approach for modeling tetrachloroethene biodegradation

    SciTech Connect

    Bagley, D.M.

    1998-11-01

    The anaerobic biodegradation of tetrachloroethene (PCE) is a reasonably well understood process. Specific organisms capable of using PCE as an electron acceptor for growth require the addition of an electron donor to remove PCE from contaminated ground waters. However, competition from other anaerobic microorganisms for added electron donor will influence the rate and completeness of PCE degradation. The approach developed here allows for the explicit modeling of PCE and byproduct biodegradation as a function of electron donor and byproduct concentrations, and the microbiological ecology of the system. The approach is general and can be easily modified for ready use with in situ ground-water models or ex situ reactor models. Simulations conducted with models developed from this approach show the sensitivity of PCE biodegradation to input parameter values, in particular initial biomass concentrations. Additionally, the dechlorination rate will be strongly influenced by the microbial ecology of the system. Finally, comparison with experimental acclimation results indicates that existing kinetic constants may not be generally applicable. Better techniques for measuring the biomass of specific organisms groups in mixed systems are required.

  4. Biodegradation potential of a modified natural product

    SciTech Connect

    Sajjad, W.

    1996-12-31

    Biodegradation potential of a modified natural product for treating petroleum contaminated soils was investigated along with some commercially available microbial cultures in three different scales from a laboratory to pilot to case studies. The modified natural product is lignocellulosic in nature and proprietary product of a company in Iowa. The production process of this product involves mechanical size reduction, blending/coating, and aerobic digestion of hay, corn cob residue, straw or crop residue in presence of poultry manure. The degradation kinetics of the petroleum products in the contaminated soils were measured both directly and indirectly. Residual petroleum products in different soils (treated and untreated) at various time periods were quantified by gas chromatographic (GC) analysis on extracted samples. The indirect assessment of the kinetics of biological activity involved the measurement of CO{sub 2} evolved from flasks (250 ml capacity) containing contaminated soil (about 50 ml) with various treatments. The results indicated that the biodegradation kinetics of petroleum products in the contaminated soils were significantly improved by treatment with this modified natural product. In most cases tested, this product performed significantly better than the available commercial bacterial cultures for biological removal of petroleum products from contaminated soils. This study also demonstrated the significance of temperature and moisture content in biodegradation kinetics.

  5. Water-curable and biodegradable prepolymers.

    PubMed

    Kobayashi, H; Hyon, S H; Ikada, Y

    1991-12-01

    In an attempt to develop biodegradable polymers which can be shaped in situ and adhere to living tissues, we synthesized esterurethane prepolymers which can be cured upon contact with water in living tissues. First, D,L-lactide polymerization or D,L-lactide-epsilon-caprolactone (50:50) copolymerization was carried out using ethylene glycol or poly(ethylene glycol) as initiator to obtain hydroxyl-terminated biodegradable polyesters. They were then reacted with an excess of diisocyanate such as hexamethylene diisocyanate, toluylene diisocyanate, and diphenylmethane diisocyanate to introduce a reactive isocyanate group to both of the end groups of the polyesters. The isocyanate-terminated prepolymers could be cured in the presence of water and the cured polymers were degraded by hydrolysis both in vitro and in vivo. It was found that the presence of appropriate amounts of hydrophilic units in the main chain was essential for giving a high curing rate and a high degradation rate for the biodegradable urethane prepolymers. The tissue responses to the cured polymers were not severe. PMID:1794996

  6. Biodegradation potential of photocatalyzed surfactant washwater.

    PubMed

    Maillacheruvu, K; Buck, L; Lee, E

    2001-01-01

    Enhanced release of hydrophobic compounds from a soil matrix can be achieved by use of soil-washing or soil-flushing using various surfactants. However, the surfactants used in achieving the desorption of organic contaminants may also cause a problem in subsequent removal/disposal of these contaminants. UV radiation in the presence of TiO2 as a pre-treatment step to achieve initial (or partial) breakdown of naphthalene and Sodium Dodecyl Sulfate (SDS) using batch experiments indicated that 56% to 88% naphthalene degradation occurred within 30 minutes to one hour. Preliminary results on the estimate of the batch aerobic biodegradation potential of photocatalyzed washwater containing naphthalene and SDS suggested that SDS was the major carbon and energy source for an activated sludge enrichment culture and an enrichment culture obtained from microorganisms at a contaminated site. Continuous-flow stirred tank reactors (CSTRs) with with a solids retention time (SRT) of 4 days were not effective, but an SRT of 8 days was successful in biodegrading the naphthalene and surfactant. These results indicated that photocatalytic treatment as a pre-treatment step followed by a biodegradation step may offer potential in cleaning up surfactant washwaters containing organic contaminants. PMID:11501312

  7. Directions for environmentally biodegradable polymer research

    SciTech Connect

    Swift, G. )

    1993-03-01

    A major factor promoting interest in biodegradable polymers is the growing concern raised by the recalcitrance and unknown environmental fate of many of the currently used synthetic polymers. These polymers include both water-soluble and water-insoluble types. The former are generally specialty polymers with functional groups that effect water solubility such as carboxyl, hydroxyl, amido, etc.; the latter are usually nonfunctional polymers commonly referred to as commodity plastics. Both types of polymers are widely used in many applications. Water-soluble polymers are used, for example, in cosmetics, water treatment, dispersants, thickeners, detergents, and superabsorbents, and they include poly(acrylic acid), polyacrylamide, poly(vinyl alcohol), and poly(ethylene glycol). Plastics are used in packaging, disposable diaper backing, fishing nets, and agricultural film; they include polymers such as polyethylene, polypropylene, polystyrene, poly(vinyl chloride), poly(ethylene terephthalate), and Nylon 6.6. In this Account, the author presents a personal perspective on definitions and test protocols for biodegradable polymers as well as how they will influence the future direction and developments in the field. However, before doing so he digresses briefly to present a commentary on the role of biodegradable polymers in environmental waste management. This should be useful for those readers unfamiliar with the subject, and it will set the stage for the rest of the discussion. 36 refs., 3 figs.

  8. Ductile electroactive biodegradable hyperbranched polylactide copolymers enhancing myoblast differentiation.

    PubMed

    Xie, Meihua; Wang, Ling; Guo, Baolin; Wang, Zhong; Chen, Y Eugene; Ma, Peter X

    2015-12-01

    Myotube formation is crucial to restoring muscular functions, and biomaterials that enhance the myoblast differentiation into myotubes are highly desirable for muscular repair. Here, we report the synthesis of electroactive, ductile, and degradable copolymers and their application in enhancing the differentiation of myoblasts to myotubes. A hyperbranched ductile polylactide (HPLA) was synthesized and then copolymerized with aniline tetramer (AT) to produce a series of electroactive, ductile and degradable copolymers (HPLAAT). The HPLA and HPLAAT showed excellent ductility with strain to failure from 158.9% to 42.7% and modulus from 265.2 to 758.2 MPa. The high electroactivity of the HPLAAT was confirmed by UV spectrometer and cyclic voltammogram measurements. These HPLAAT polymers also showed improved thermal stability and controlled biodegradation rate compared to HPLA. Importantly, when applying these polymers for myotube formation, the HPLAAT significantly improved the proliferation of C2C12 myoblasts in vitro compared to HPLA. Furthermore, these polymers greatly promoted myogenic differentiation of C2C12 cells as measured by quantitative analysis of myotube number, length, diameter, maturation index, and gene expression of MyoD and TNNT. Together, our study shows that these electroactive, ductile and degradable HPLAAT copolymers represent significantly improved biomaterials for muscle tissue engineering compared to HPLA. PMID:26335860

  9. Biodegradability Evaluation of Polymers by ISO 14855-2

    PubMed Central

    Funabashi, Masahiro; Ninomiya, Fumi; Kunioka, Masao

    2009-01-01

    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

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

    PubMed

    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

  11. Biodegradation mechanism of 1H-1,2,4-triazole by a newly isolated strain Shinella sp. NJUST26

    PubMed Central

    Wu, Haobo; Shen, Jinyou; Wu, Ruiqin; Sun, Xiuyun; Li, Jiansheng; Han, Weiqing; Wang, Lianjun

    2016-01-01

    The highly recalcitrant 1H-1,2,4-triazole (TZ) is widely used in the synthesis of agricultural pesticide and considered to be an environmental pollutant. In this study, a novel strain NJUST26 capable of utilizing TZ as the sole carbon and nitrogen source, was isolated from TZ-contaminated soil, and identified as Shinella sp. The biodegradation assays suggested that optimal temperature and pH for TZ degradation by NJUST26 were 30 °C and 6–7, respectively. With the increase of initial TZ concentration from 100 to 320 mg L−1, the maximum volumetric degradation rate increased from 29.06 to 82.96 mg L−1 d−1, indicating high tolerance of NJUST26 towards TZ. TZ biodegradation could be accelerated through the addition of glucose, sucrose and yeast extract at relatively low dosage. The main metabolites, including 1,2-dihydro-3H-1,2,4-triazol-3-one (DHTO), semicarbazide and urea were identified. Based on these results, biodegradation pathway of TZ by NJUST26 was proposed, i.e., TZ was firstly oxidized to DHTO, and then the cleavage of DHTO ring occurred to generate N-hydrazonomethyl-formamide, which could be further degraded to biodegradable semicarbazide and urea. PMID:27436634

  12. Biodegradation mechanism of 1H-1,2,4-triazole by a newly isolated strain Shinella sp. NJUST26.

    PubMed

    Wu, Haobo; Shen, Jinyou; Wu, Ruiqin; Sun, Xiuyun; Li, Jiansheng; Han, Weiqing; Wang, Lianjun

    2016-01-01

    The highly recalcitrant 1H-1,2,4-triazole (TZ) is widely used in the synthesis of agricultural pesticide and considered to be an environmental pollutant. In this study, a novel strain NJUST26 capable of utilizing TZ as the sole carbon and nitrogen source, was isolated from TZ-contaminated soil, and identified as Shinella sp. The biodegradation assays suggested that optimal temperature and pH for TZ degradation by NJUST26 were 30 °C and 6-7, respectively. With the increase of initial TZ concentration from 100 to 320 mg L(-1), the maximum volumetric degradation rate increased from 29.06 to 82.96 mg L(-1) d(-1), indicating high tolerance of NJUST26 towards TZ. TZ biodegradation could be accelerated through the addition of glucose, sucrose and yeast extract at relatively low dosage. The main metabolites, including 1,2-dihydro-3H-1,2,4-triazol-3-one (DHTO), semicarbazide and urea were identified. Based on these results, biodegradation pathway of TZ by NJUST26 was proposed, i.e., TZ was firstly oxidized to DHTO, and then the cleavage of DHTO ring occurred to generate N-hydrazonomethyl-formamide, which could be further degraded to biodegradable semicarbazide and urea. PMID:27436634

  13. Biodegradable Poly(ester urethane)urea Elastomers with Variable Amino Content for Subsequent Functionalization with Phosphorylcholine

    PubMed Central

    Fang, Jun; Ye, Sang-Ho; Shankarraman, Venkat; Huang, Yixian; Mo, Xiumei; Wagner, William R.

    2015-01-01

    While surface modification is well suited for imparting biomaterials with specific functionality for favorable cell interactions, the modification of degradable polymers would be expected to provide only temporary benefit. Bulk modification by incorporating pendant reactive groups for subsequent functionalization of biodegradable polymers would provide a more enduring approach. Towards this end, a series of biodegradable poly(ester urethane)urea elastomers with variable amino content (PEUU-NH2 polymers) were developed. Carboxylated phosphorycholine was synthesized and conjugated to the PEUU-NH2 polymers for subsequent bulk functionalization to generate PEUU-PC polymers. Synthesis was verified by 1H NMR, X-ray photoelectron spectroscopy and ATR-FTIR. The impact of amine incorporation and phosphorylcholine conjugation was shown on mechanical, thermal and degradation properties. Water absorption increased with increasing amine content, and further with PC conjugation. In wet conditions, tensile strength and initial modulus generally decreased with increasing hydrophilicity, but remained in the range of 5–30 MPa and 10–20 MPa respectively. PC conjugation was associated with significantly reduced platelet adhesion in blood contact testing and the inhibition of rat vascular smooth muscle cell proliferation. These biodegradable PEUU-PC elastomers offer attractive properties for applications as non-thrombogenic, biodegradable coatings and for blood-contacting scaffold applications. Further, the PEUU-NH2 base polymers offer the potential to have multiple types of biofunctional groups conjugated onto the backbone to address a variety of design objectives. PMID:25132273

  14. Citric acid-derived in situ crosslinkable biodegradable polymers for cell delivery

    PubMed Central

    Gyawali, Dipendra; Nair, Parvathi; Zhang, Yi; Tran, Richard T.; Zhang, Chi; Samchukov, Mikhail; Makarov, Marina; Kim, Harry; Yang, Jian

    2010-01-01

    Herein, we report the first citric acid (CA)-derived in situ crosslinkable biodegradable polymer, poly(ethylene glycol) maleate citrate (PEGMC). The synthesis of PEGMC could be carried out via a one-pot polycondensation reaction without using organic solvents or catalysts. PEGMC could be in-situ crosslinked into elastomeric PPEGMC hydrogels. The performance of hydrogels in terms of swelling, degradation, and mechanical properties were highly dependent on the molar ratio of monomers, crosslinker concentration, and crosslinking mechanism used in the synthesis process. Cyclic conditioning tests showed that PPEGMC hydrogels could be compressed up to 75% strain without permanent deformation and with negligible hysteresis. Water-soluble PEGMC demonstrated excellent cytocompatibilty in vitro. The degradation products of PPEGMC also showed minimal cytotoxicity in vitro. Animal studies in rats clearly demonstrated the excellent injectability of PEGMC and degradability of the in situ-formed PPEGMC. PPEGMC elicited minimal inflammation in the early stages post-injection and was completely degraded within 30 days in rats. In conclusion, the development of CA-derived injectable biodegradable PEGMC presents numerous opportunities for material innovation and offers excellent candidate materials for in situ tissue engineering and drug delivery applications. PMID:20800893

  15. An entropy spring model for the Young's modulus change of biodegradable polymers during biodegradation.

    PubMed

    Wang, Ying; Han, Xiaoxiao; Pan, Jingzhe; Sinka, Csaba

    2010-01-01

    This paper presents a model for the change in Young's modulus of biodegradable polymers due to hydrolysis cleavage of the polymer chains. The model is based on the entropy spring theory for amorphous polymers. It is assumed that isolated polymer chain cleavage and very short polymer chains do not affect the entropy change in a linear biodegradable polymer during its deformation. It is then possible to relate the Young's modulus to the average molecular weight in a computer simulated hydrolysis process of polymer chain sessions. The experimental data obtained by Tsuji [Tsuji, H., 2002. Autocatalytic hydrolysis of amorphous-made polylactides: Effects of L-lactide content, tacticity, and enantiomeric polymer blending. Polymers 43, 1789-1796] for poly(L-lactic acid) and poly(D-lactic acid) are examined using the model. It is shown that the model can provide a common thread through Tsuji's experimental data. A further numerical case study demonstrates that the Young's modulus obtained using very thin samples, such as those obtained by Tsuji, cannot be directly used to calculate the load carried by a device made of the same polymer but of various thicknesses. This is because the Young's modulus varies significantly in a biodegradable device due to the heterogeneous nature of the hydrolysis reaction. The governing equations for biodegradation and the relation between the Young's modulus and average molecular weight can be combined to calculate the load transfer from a degrading device to a healing bone. PMID:19878898

  16. Biodegradable and semi-biodegradable composite hydrogels as bone substitutes: morphology and mechanical characterization.

    PubMed

    Sanginario, V; Ginebra, M P; Tanner, K E; Planell, J A; Ambrosio, L

    2006-05-01

    Biodegradable and semi-biodegradable composite hydrogels are proposed as bone substitutes. They consist of an hydrophilic biodegradable polymer (HYAFF 11) as matrix and two ceramic powders (alpha-TCP and HA) as reinforcement. Both components of these composites have been of great interest in biomedical applications due to their excellent biocompatibility and tissue interactions, however they have never been investigated as bone substitute composites. Morphological and mechanical analysis have shown that the two fillers behave in a very different way. In the HYAFF 11/alpha-TCP composite, alpha-TCP is able to hydrolyze in contact with water while in the HYAFF 11 matrix. As a result, the composite sets and hardens, and entangled CDHA crystals are formed in the hydrogel phase and increases in the mechanical properties are obtained. In the HYAFF11/HA composite the ceramic reinforcement acts as inert phase leading to lower mechanical properties. Both mechanical properties and microstructure analysis have demonstrated the possibility to design hydrophilic biodegradable composite structures for bone tissue substitution applications. PMID:16688585

  17. Isomer-specific biodegradation of nonylphenol in an activated sludge bioreactor and structure-biodegradability relationship.

    PubMed

    Lu, Zhijiang; Reif, Rubén; Gan, Jay

    2015-01-01

    Nonylphenol (NP), one of the priority hazardous substances, is in fact a mixture of numerous isomers. It is inconclusive whether or not biodegradation during wastewater treatment process is isomer-specific, leading to the environmental release of NP in different isomer profiles. In this study, we evaluated the isomer selectivity of 19 NP isomers in a laboratory-scale continuous flow conventional activated sludge bioreactor under various operational conditions. The removal efficiency of NP isomers ranged from 90 to 99%, depending on the operational conditions and isomer structures. Isomer selective biodegradation resulted in the increase of composition of recalcitrant isomers, such as, NP₁₉₃a/b, NP₁₁₀a and NP₁₉₄ in the effluent. Moreover, biodegradability was related to the bulkiness of α-substituents and followed α-dimethyl > α-ethyl-α-methyl > α-methyl-α-n-propyl > α-iso-propyl-α-methyl. Steric effect index, a quantitative descriptor of steric hindrance, was linearly correlated with residues of NP isomers in the effluent (R² = 0.76). Decrease of temperature to 10 °C decreased the overall biodegradability and also enhanced the relative enrichment of recalcitrant isomers. These findings suggest that isomer compositions of NP entering the environment may be different from those in technical mixtures and that isomeric selectivity should be taken into account to better understand the occurrence, fate, and ecological risks of NP. PMID:25462736

  18. Biodegradation of brominated and organophosphorus flame retardants.

    PubMed

    Waaijers, Susanne L; Parsons, John R

    2016-04-01

    Brominated flame retardants account for about 21% of the total production of flame retardants and many of these have been identified as persistent, bioaccumulative and toxic. Nevertheless, debromination of these chemicals under anaerobic conditions is well established, although this can increase their toxicity. Consequently, the production and use of these chemicals has been restricted and alternative products have been developed. Many of these are brominated compounds and share some of the disadvantages of the chemicals they are meant to replace. Therefore, other, nonbrominated, flame retardants such as organophosphorus compounds are also being used in increasing quantities, despite the fact that knowledge of their biodegradation and environmental fate is often lacking. PMID:26748263

  19. Biodegradation of petroleum hydrocarbons in hypersaline environments.

    PubMed

    Martins, Luiz Fernando; Peixoto, Raquel Silva

    2012-07-01

    Literature on hydrocarbon degradation in extreme hypersaline media presents studies that point to a negative effect of salinity increase on hydrocarbonoclastic activity, while several others report an opposite tendency. Based on information available in the literature, we present a discussion on the reasons that justify these contrary results. Despite the fact that microbial ability to metabolize hydrocarbons is found in extreme hypersaline media, indeed some factors are critical for the occurrence of hydrocarbon degradation in such environments. How these factors affect hydrocarbon degradation and their implications for the assessment of hydrocarbon biodegradation in hypersaline environments are presented in this review. PMID:24031900

  20. Biodegradation of petroleum hydrocarbons in hypersaline environments

    PubMed Central

    Martins, Luiz Fernando; Peixoto, Raquel Silva

    2012-01-01

    Literature on hydrocarbon degradation in extreme hypersaline media presents studies that point to a negative effect of salinity increase on hydrocarbonoclastic activity, while several others report an opposite tendency. Based on information available in the literature, we present a discussion on the reasons that justify these contrary results. Despite the fact that microbial ability to metabolize hydrocarbons is found in extreme hypersaline media, indeed some factors are critical for the occurrence of hydrocarbon degradation in such environments. How these factors affect hydrocarbon degradation and their implications for the assessment of hydrocarbon biodegradation in hypersaline environments are presented in this review. PMID:24031900

  1. Biodegradable and Renal Clearable Inorganic Nanoparticles

    PubMed Central

    Ehlerding, Emily B.; Chen, Feng; Cai, Weibo

    2016-01-01

    Personalized treatment plans for cancer therapy have been at the forefront of oncology research for many years. With the advent of many novel nanoplatforms, this goal is closer to realization today than ever before. Inorganic nanoparticles hold immense potential in the field of nano-oncology, but have considerable toxicity concerns that have limited their translation to date. In this review, an overview of emerging biologically safe inorganic nanoplatforms is provided, along with considerations of the challenges that need to be overcome for cancer theranostics with inorganic nanoparticles to become a reality. The clinical and preclinical studies of both biodegradable and renal clearable inorganic nanoparticles are discussed, along with their implications. PMID:27429897

  2. Biosynthesis and biodegradation of wood components

    SciTech Connect

    Higuchi, T.

    1985-01-01

    A textbook containing 22 chapters by various authors covers the structure of wood, the localization of polysaccharides and lignins in wood cell walls, metabolism and synthetic function of cambial tissue, cell organelles and their function in the biosynthesis of cell wall components, biosynthesis of plant cell wall polysaccharides, lignin, cutin, suberin and associated waxes, phenolic acids and monolignols, quinones, flavonoids, tannins, stilbenes and terpenoid wood extractives, the occurrence of extractives, the metabolism of phenolic acids, wood degradation by micro-organisms and fungi, and biodegradation of cellulose, hemicelluloses, lignin, and aromatic extractives of wood. An index is included.

  3. Compared in vivo toxicity in mice of lung delivered biodegradable and non-biodegradable nanoparticles.

    PubMed

    Aragao-Santiago, Letícia; Hillaireau, Hervé; Grabowski, Nadège; Mura, Simona; Nascimento, Thais L; Dufort, Sandrine; Coll, Jean-Luc; Tsapis, Nicolas; Fattal, Elias

    2016-04-01

    To design nanoparticle (NP)-based drug delivery systems for pulmonary administration, biodegradable materials are considered safe, but their potential toxicity is poorly explored. We here explore the lung toxicity in mice of biodegradable nanoparticles (NPs) and compare it to the toxicity of non-biodegradable ones. NP formulations of poly(d,l-lactide-co-glycolide) (PLGA) coated with chitosan (CS), poloxamer 188 (PF68) or poly(vinyl alcohol) (PVA), which renders 200 nm NPs of positive, negative or neutral surface charge respectively, were analyzed for their biodistribution by in vivo fluorescence imaging and their inflammatory potential after single lung nebulization in mice. After exposure, analysis of bronchoalveolar lavage (BAL) cell population, protein secretion and cytokine release as well as lung histology were carried out. The inflammatory response was compared to the one induced by non-biodegradable counterparts, namely, TiO2 of rutile and anatase crystal form and polystyrene (PS). PLGA NPs were mostly present in mice lungs, with little passage to other organs. An increase in neutrophil recruitment was observed in mice exposed to PS NPs 24 h after nebulization, which declined at 48 h. This result was supported by an increase in interleukin (IL)-6 and tumor necrosis factor α (TNFα) in BAL supernatant at 24 h. TiO2 anatase NPs were still present in lung cells 48 h after nebulization and induced the expression of pro-inflammatory cytokines and the recruitment of polymorphonuclear cells to BAL. In contrast, regardless of their surface charge, PLGA NPs did not induce significant changes in the inflammation markers analyzed. In conclusion, these results point out to a safe use of PLGA NPs regardless of their surface coating compared to non-biodegradable ones. PMID:26573338

  4. SCREENING OF BACTERIAL PRODUCTS FOR THEIR CRUDE OIL BIODEGRADATION EFFECTIVENESS

    EPA Science Inventory

    Although petroleum hydrocarbons have been known to be biodegradable for decades (1-5), use of microbial cultures to enhance natural biodegradation (bioaugmentation) has met with limited success (6-10). Despite the paucity of controlled field studies demonstrating the effectivene...

  5. Biodegradation of Petroleum Hydrocarbon in the Vadose Zone

    EPA Science Inventory

    There are two major impediments to a better understanding of the influence of biodegradation on the risk of intrusion of petroleum vapors. We describe the contribution of biodegradation as an attenuation factor between the source and the receptor. The use of attenuation factors...

  6. KINETICS OF ETHANOL BIODEGRADATION UNDER METHANOGENIC CONDITIONS IN GASOLINE SPILLS

    EPA Science Inventory

    Ethanol is commonly used as a fuel oxygenate. A concern has been raised that biodegradation of ethanol from a spill of gasoline may inhibit the natural biodegradation of fuel hydrocarbons, including benzene. Ethanol is miscible in water, and ethanol is readily metabolized by mi...

  7. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Aerobic aquatic biodegradation. 796.3100 Section 796.3100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Transformation Processes § 796.3100 Aerobic aquatic biodegradation. (a)...

  8. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 33 2012-07-01 2012-07-01 false Aerobic aquatic biodegradation. 796.3100 Section 796.3100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Transformation Processes § 796.3100 Aerobic aquatic biodegradation. (a)...

  9. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Aerobic aquatic biodegradation. 796.3100 Section 796.3100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Transformation Processes § 796.3100 Aerobic aquatic biodegradation. (a)...

  10. Removal and biodegradation of nonylphenol by immobilized Chlorella vulgaris.

    PubMed

    Gao, Q T; Wong, Y S; Tam, N F Y

    2011-11-01

    The removal and biodegradation of nonylphenol (NP) by alginate-immobilized cells of Chlorella vulgaris were compared with their respective free cultures. The effects of four cell densities of 10(4) per algal bead were investigated, as were the four algal bead concentrations, with regard to the removal and biodegradation of NP. Although immobilization significantly decreased the growth rate and NP's biodegradation efficiency of C. vulgaris, NP removal over a short period was enhanced. The NP removal mechanism by immobilized cells was similar to that by free cells, including adsorption onto alginate matrix and algal cells, absorption within cells and cellular biodegradation. The optimal cell density and bead concentration for the removal and biodegradation of NP was 50-100×10(4) cells algal bead(-1) and 2-4 beads ml(-1) of wastewater, respectively. These results demonstrated that immobilized C. vulgaris cells under optimal biomass and photoautotrophic conditions are effective in removing NP from contaminated water. PMID:21944284

  11. Best conditions for biodegradation of diesel oil by chemometric tools

    PubMed Central

    Kaczorek, Ewa; Bielicka-Daszkiewicz, Katarzyna; Héberger, Károly; Kemény, Sándor; Olszanowski, Andrzej; Voelkel, Adam

    2014-01-01

    Diesel oil biodegradation by different bacteria-yeast-rhamnolipids consortia was tested. Chromatographic analysis of post-biodegradation residue was completed with chemometric tools (ANOVA, and a novel ranking procedure based on the sum of ranking differences). These tools were used in the selection of the most effective systems. The best results of aliphatic fractions of diesel oil biodegradation were observed for a yeast consortia with Aeromonas hydrophila KR4. For these systems the positive effect of rhamnolipids on hydrocarbon biodegradation was observed. However, rhamnolipids addition did not always have a positive influence on the biodegradation process (e.g. in case of yeast consortia with Stenotrophomonas maltophila KR7). Moreover, particular differences in the degradation pattern were observed for lower and higher alkanes than in the case with C22. Normally, the best conditions for “lower” alkanes are Aeromonas hydrophila KR4 + emulsifier independently from yeasts and e.g. Pseudomonas stutzeri KR7 for C24 alkane. PMID:24948922

  12. Porous Biodegradable Metals for Hard Tissue Scaffolds: A Review

    PubMed Central

    Yusop, A. H.; Bakir, A. A.; Shaharom, N. A.; Abdul Kadir, M. R.; Hermawan, H.

    2012-01-01

    Scaffolds have been utilized in tissue regeneration to facilitate the formation and maturation of new tissues or organs where a balance between temporary mechanical support and mass transport (degradation and cell growth) is ideally achieved. Polymers have been widely chosen as tissue scaffolding material having a good combination of biodegradability, biocompatibility, and porous structure. Metals that can degrade in physiological environment, namely, biodegradable metals, are proposed as potential materials for hard tissue scaffolding where biodegradable polymers are often considered as having poor mechanical properties. Biodegradable metal scaffolds have showed interesting mechanical property that was close to that of human bone with tailored degradation behaviour. The current promising fabrication technique for making scaffolds, such as computation-aided solid free-form method, can be easily applied to metals. With further optimization in topologically ordered porosity design exploiting material property and fabrication technique, porous biodegradable metals could be the potential materials for making hard tissue scaffolds. PMID:22919393

  13. Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

    SciTech Connect

    McCarty, Perry L.; Spormann, Alfred M.; Criddle, Craig S.

    2001-06-01

    The anaerobic biodegradation of chlorinated solvents is of great interest both for natural attenuation and for engineered remediation of these hazardous contaminants in groundwater. Compounds to be studied are carbon tetrachloride (CT) and the chlorinated ethenes, tetrachloroethene (PCE), trichloroethene (TCE) cis-1,2-dichloroethene (cDCE), and vinyl chloride (VC). The chlorinated solvents often are present as dense non-aqueous-phase liquids (DNAPLs), which are difficult to remove. Biodegradation of DNAPLs was previously thought not possible because of toxicity, but recent evidence indicates that under the right conditions, biodegradation is possible. Anaerobic biodegradation of DNAPLs is the major subject of this research. The specific objectives of this multi-investigator effort are: (1) Evaluate the potential for chlorinated solvent biodegradation near DNAPLs, (2) Provide a molecular understanding of the biological mechanisms involved, (3) Determine cellular components involved in carbon tetrachloride transformation by Pseudomonas stutzeri strain KC without chloroform formation.

  14. Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

    SciTech Connect

    McCarty, Perry L.; Spormann, Alfred M.; Criddle, Craig S.

    2003-06-01

    The anaerobic biodegradation of chlorinated solvents is of great interest both for natural attenuation and for engineered remediation of these hazardous contaminants in groundwater. Compounds to be studied are carbon tetrachloride (CT) and the chlorinated ethenes, tetrachloroethene (PCE), trichloroethene (TCE) cis-1,2-dichloroethene (cDCE), and vinyl chloride (VC). The chlorinated solvents often are present as dense non-aqueous-phase liquids (DNAPLs), which are difficult to remove. Biodegradation of DNAPLs was previously thought not possible because of toxicity, but recent evidence indicates that under the right conditions, biodegradation is possible. Anaerobic biodegradation of DNAPLs is the major subject of this research. The specific objectives of this multi-investigator effort are: (1) Evaluate the potential for chlorinated solvent biodegradation near DNAPLs, (2) Provide a molecular understanding of the biological mechanisms involved, (3) Determine cellular components involved in carbon tetrachloride transformation by Pseudomonas stutzeri strain KC without chloroform formation.

  15. Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

    SciTech Connect

    McCarty, Perry L.; Spormann, Alfred M.; Criddle, Craig S.

    2002-06-01

    The anaerobic biodegradation of chlorinated solvents is of great interest both for natural attenuation and for engineered remediation of these hazardous contaminants in groundwater. Compounds to be studied are carbon tetrachloride (CT) and the chlorinated ethenes, tetrachloroethene (PCE), trichloroethene (TCE) cis-1,2-dichloroethene (cDCE), and vinyl chloride (VC). The chlorinated solvents often are present as dense non-aqueous-phase liquids (DNAPLs), which are difficult to remove. Biodegradation of DNAPLs was previously thought not possible because of toxicity, but recent evidence indicates that under the right conditions, biodegradation is possible. Anaerobic biodegradation of DNAPLs is the major subject of this research. The specific objectives of this multi-investigator effort are: (1) Evaluate the potential for chlorinated solvent biodegradation near DNAPLs, (2) Provide a molecular understanding of the biological mechanisms involved, (3) Determine cellular components involved in carbon tetrachloride transformation by Pseudomonas stutzeri strain KC without chloroform formation.

  16. Monitoring Biodegradation of Magnesium Implants with Sensors

    NASA Astrophysics Data System (ADS)

    Zhao, Daoli; Wang, Tingting; Guo, Xuefei; Kuhlmann, Julia; Doepke, Amos; Dong, Zhongyun; Shanov, Vesselin N.; Heineman, William R.

    2016-04-01

    Magnesium and its alloys exhibit properties such as high strength, light weight, and in vivo corrosion that make them promising candidates for the development of biodegradable metallic implant materials for bone repair, stents and other medical applications. Sensors have been used to monitor the corrosion of magnesium and its alloys by measuring the concentrations of the following corrosion products: magnesium ions, hydroxyl ions and hydrogen gas. The corrosion characterization system with home-made capillary pH and Mg2+ microsensors has been developed for real-time detection of magnesium corrosion in vitro. A hydrogen gas sensor was used to monitor the corrosion of magnesium by measuring the concentration of the hydrogen gas reaction product in vivo. The high permeability of hydrogen through skin allows transdermal monitoring of the biodegradation of a magnesium alloy implanted beneath the skin by detecting hydrogen gas at the skin surface. The sensor was used to map hydrogen concentration in the vicinity of an implanted magnesium alloy.

  17. Characterization and aerobic biodegradation of selected monoterpenes

    SciTech Connect

    Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M.

    1996-12-31

    Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

  18. Fungal biodegradation of lignopolystyrene graft copolymers.

    PubMed Central

    Milstein, O; Gersonde, R; Huttermann, A; Chen, M J; Meister, J J

    1992-01-01

    White rot basidiomycetes were able to biodegrade styrene (1-phenylethene) graft copolymers of lignin containing different proportions of lignin and polystyrene [poly(1-phenylethylene)]. The biodegradation tests were run on lignin-styrene copolymerization products which contained 10.3, 32.2, and 50.4% (wt/wt) lignin. The polymer samples were incubated with the white rot fungi Pleurotus ostreatus, Phanerochaete chrysosporium, and Trametes versicolor and the brown rot fungus Gloeophyllum trabeum. White rot fungi degraded the plastic samples at a rate which increased with increasing lignin content in the copolymer sample. Both polystyrene and lignin components of the copolymer were readily degraded. Polystyrene pellets were not degradable in these tests. Degradation was verified for both incubated and control samples by weight loss, quantitative UV spectrophotometric analysis of both lignin and styrene residues, scanning electron microscopy of the plastic surface, and the presence of enzymes active in degradation during incubation. Brown rot fungus did not affect any of the plastics. White rot fungi produced and secreted oxidative enzymes associated with lignin degradation in liquid media during incubation with lignin-polystyrene copolymer. Images PMID:1444360

  19. Biodegradation of physicochemically treated polycarbonate by fungi.

    PubMed

    Artham, Trishul; Doble, Mukesh

    2010-01-11

    Two fungal strains isolated from soil and a commercial white-rot fungus, Phanerochaete chrysosporium NCIM 1170 (SF2), were tested for biodegradation of untreated, UV-, and thermal-treated bisphenol A polycarbonate (PC). The isolated strains based on 18S rDNA analysis were characterized as Engyodontium album MTP091 (SF1) and Pencillium spp. MTP093 (SF3). About 5.4% weight loss and 40% reduction in M(n) were observed for UV-treated polycarbonate in one year with SF2 strain. An increase in surface energy and oxygen content and a reduction in methyl index indicated oxidation of PC during this period. PC exposed to the SF1 strain showed a 15 degrees C decrease in glass transition temperature, indicating an increase in the number of chain ends and, hence, an increase in the free volume of polymer. No bisphenol A, the monomer of PC, was detected during the study. NMR and FTIR spectra showed the formation of methyl groups due to pretreatments. EDAX analysis exhibited surface oxidation of the PC. The current study advocates that biodegradation of PC can be enhanced by pretreatments. PMID:19961236

  20. Computational method for analysis of polyethylene biodegradation

    NASA Astrophysics Data System (ADS)

    Watanabe, Masaji; Kawai, Fusako; Shibata, Masaru; Yokoyama, Shigeo; Sudate, Yasuhiro

    2003-12-01

    In a previous study concerning the biodegradation of polyethylene, we proposed a mathematical model based on two primary factors: the direct consumption or absorption of small molecules and the successive weight loss of large molecules due to β-oxidation. Our model is an initial value problem consisting of a differential equation whose independent variable is time. Its unknown variable represents the total weight of all the polyethylene molecules that belong to a molecular-weight class specified by a parameter. In this paper, we describe a numerical technique to introduce experimental results into analysis of our model. We first establish its mathematical foundation in order to guarantee its validity, by showing that the initial value problem associated with the differential equation has a unique solution. Our computational technique is based on a linear system of differential equations derived from the original problem. We introduce some numerical results to illustrate our technique as a practical application of the linear approximation. In particular, we show how to solve the inverse problem to determine the consumption rate and the β-oxidation rate numerically, and illustrate our numerical technique by analyzing the GPC patterns of polyethylene wax obtained before and after 5 weeks cultivation of a fungus, Aspergillus sp. AK-3. A numerical simulation based on these degradation rates confirms that the primary factors of the polyethylene biodegradation posed in modeling are indeed appropriate.

  1. Optimization of low ring polycylic aromatic biodegradation

    NASA Astrophysics Data System (ADS)

    Othman, N.; Abdul-Talib, S.; Tay, C. C.

    2016-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are recalcitrance and persistence that finally turn into problematic environmental contaminants. Microbial degradation is considered to be the primary mechanism of PAHs removal from the environment due to its organic criteria. This study is carried out to optimize degradation process of low ring PAHs. Bacteria used in this study was isolated from sludge collected from Kolej Mawar, Universiti Teknologi MARA, Shah Alam, Selangor. Working condition namely, substrate concentration, bacteria concentration, pH and temperature were optimized. PAHs in the liquid sample was extracted by using solid phase microextractio equipped with a 7 µm polydimethylsiloxane (PDMS) SPME fibr. Removal of PAHs were assessed by measuring PAHs concentration using GC-FID. Results from the optimization study of biodegradation indicated that maximum rate of PAHs removal occurred at 100 mgL-1 of PAHs, 10% bacteria concentration, pH 7.0 and 30°C. These working condition had proved the effectiveness of using bacteria in biodegradation process of PAHs.

  2. Immunological Response to Biodegradable Magnesium Implants

    NASA Astrophysics Data System (ADS)

    Pichler, Karin; Fischerauer, Stefan; Ferlic, Peter; Martinelli, Elisabeth; Brezinsek, Hans-Peter; Uggowitzer, Peter J.; Löffler, Jörg F.; Weinberg, Annelie-Martina

    2014-04-01

    The use of biodegradable magnesium implants in pediatric trauma surgery would render surgical interventions for implant removal after tissue healing unnecessary, thereby preventing stress to the children and reducing therapy costs. In this study, we report on the immunological response to biodegradable magnesium implants—as an important aspect in evaluating biocompatibility—tested in a growing rat model. The focus of this study was to investigate the response of the innate immune system to either fast or slow degrading magnesium pins, which were implanted into the femoral bones of 5-week-old rats. The main alloying element of the fast-degrading alloy (ZX50) was Zn, while it was Y in the slow-degrading implant (WZ21). Our results demonstrate that degrading magnesium implants beneficially influence the immune system, especially in the first postoperative weeks but also during tissue healing and early bone remodeling. However, rodents with WZ21 pins showed a slightly decreased phagocytic ability during bone remodeling when the degradation rate reached its maximum. This may be due to the high release rate of the rare earth-element yttrium, which is potentially toxic. From our results we conclude that magnesium implants have a beneficial effect on the innate immune system but that there are some concerns regarding the use of yttrium-alloyed magnesium implants, especially in pediatric patients.

  3. Biodegradation of cresol isomers in anoxic aquifers.

    PubMed Central

    Smolenski, W J; Suflita, J M

    1987-01-01

    The biodegradation of o-, m-, and p-cresol was examined in material obtained from a shallow anaerobic alluvial sand aquifer. The cresol isomers were preferentially metabolized, with p-cresol being the most easily degraded. m-Cresol was more persistent than the para-isomer, and o-cresol persisted for over 90 days. Biodegradation of cresol isomers was favored under sulfate-reducing conditions (SRC) compared with that under methanogenic conditions (MC). Slurries that were acclimated to p-cresol metabolism transformed this substrate at 18 and 330 nmol/h per g (dry weight) for MC and SRC, respectively. Inhibition of electron flow to sulfate reduction with 2.0 mM molybdate reduced p-cresol metabolism in incubations containing sulfate. When methanogenesis was blocked with 5 mM bromoethanesulfonic acid in incubations lacking sulfate, p-cresol catabolism was retarded. Under SRC 3.4 mol of sulfate was consumed per mol of p-cresol metabolized. The addition of sulfate to methanogenic incubations stimulated p-cresol degradation. Simultaneous adaptation studies in combination with spectrophotometric and chromatographic analysis of metabolites indicated that p-cresol was oxidized under SRC to p-hydroxybenzoate via the corresponding alcohol and aldehyde. This series of reactions was inhibited under sulfate-limited or aerobic conditions. Therefore, the primary catabolic event for p-cresol decomposition under SRC appears to involve the hydroxylation of the aryl methyl group. PMID:3579279

  4. Biodegradation of alachlor by soil streptomycetes.

    PubMed

    Durães Sette, L; Mendonça Alves Da Costa, L A; Marsaioli, A J; Manfio, G P

    2004-06-01

    Streptomycetes resistant to the herbicide alachlor [2-chloro-2',6'-diethyl- N-(methoxymethyl) acetanilide] were used in degradation assays to characterize the products of alachlor biodegradation. Of six strains tested, Streptomyces sp. LS166, LS177, and LS182 were able to grow at an alachlor concentration of 144 mg l(-1) and degraded approximately 60-75% of the alachlor in 14 days, as evaluated by high performance liquid chromatography. The alachlor biodegradation products were identified by gas chromatography-mass spectrometry based on mass spectral data and fragmentation patterns. All compounds detected in these assays were similar for all streptomycetes strains tested, and involved dechlorination with subsequent N-dealkylation and cyclization of the remaining N-substituent with one of the ethyl groups to produce indole and quinoline derivatives. The enzymatic pathway used by Streptomyces sp. LS182 did not generate DEA (2',6'-diethylaniline), a carcinogenic derivative of alachlor reported in other studies. Given the high degradation rates observed here, the Streptomyces strains tested may be useful in the degradation/detoxification processes of alachlor. PMID:14727088

  5. Biodegradable cellulose acetate nanofiber fabrication via electrospinning.

    PubMed

    Christoforou, Theopisti; Doumanidis, Charalabos

    2010-09-01

    Nanofiber manufacturing is one of the key advancements in nanotechnology today. Over the past few years, there has been a tremendous growth of research activities to explore electrospinning for nanofiber formation from a rich variety of materials. This quite simple and cost effective process operates on the principle that the solution is extracted under the action of a high electric field. Once the voltage is sufficiently high, a charged jet is ejected following a complicated looping trajectory. During its travel, the solvent evaporates leaving behind randomly oriented nanofibers accumulated on the collector. The combination of their nanoscale dimensionality, high surface area, porosity, flexibility and superior strength makes the electrospun fibers suitable for several value-added applications, such as filters, protecting clothes, high performance structures and biomedical devices. In this study biodegradable cellulose acetate (CA) nanofibrous membranes were produced using electrospinning. The device utilized consisted of a syringe equipped with a metal needle, a microdialysis pump, a high voltage supply and a collector. The morphology of the yielded fibers was determined using SEM. The effect of various parameters, including electric field strength, tip-to-collector distance, solution feed rate and composition on the morphological features of the electrospun fibers was examined. The optimum operating conditions for the production of uniform, non-beaded fibers with submicron diameter were also explored. The biodegradable CA nanofiber membranes are suitable as tissue engineering scaffolds and as reinforcements of biopolymer matrix composites in foils by ultrasonic welding methods. PMID:21133179

  6. Neutralization and biodegradation of sulfur mustard

    SciTech Connect

    Harvey, S.P.; Beaudry, W.T.; Szafraniec, L.L.

    1995-12-31

    One technology recommended for consideration for the disposal of the U.S. Chemical Stockpile is chemical neutralization followed by biodegradation. In the case of sulfur mustard ({open_quotes}mustard gas{close_quotes}, 2,2{prime}-dichlorodiethyl sulfide), alkaline hydrolysis yields a detoxified and biodegradable product. The hydrolysis reaction was studied with respect to the effects of temperature and sulfur mustard concentration on the rate and products of the reaction. A 28-fold overall rate enhancement was observed at 70{degrees}C vs. 30{degrees}C corresponding to an enthalpy of activation value of 17.9 Kcal/mole. Material balance studies conducted by {sup 1}H Nuclear Magnetic Resonance analysis showed that the products of the reaction consisted of thiodiglycol was relatively greater at lower sulfur mustard concentrations and higher temperatures. As temperatures were decreased or sulfur mustard concentrations was increased, the proportion of ether-type compounds increased accordingly. Conditions of 1% (vol//vol) sulfur mustard, 5% stoichiometric excess of NaOH and 90{degrees}C were selected for generation of the hydrolyzed bioreactor influent material. The bioreactor was seeded with activated sludge and was initially operated as 5 liter sequencing batch reactor with a hydraulic residence time of approximately days. Early results show total organic carbon removal of greater than 90%.

  7. Wood biodegradation in laboratory-scale landfills.

    PubMed

    Wang, Xiaoming; Padgett, Jennifer M; De la Cruz, Florentino B; Barlaz, Morton A

    2011-08-15

    The objective of this research was to characterize the anaerobic biodegradability of major wood products in municipal waste by measuring methane yields, decay rates, the extent of carbohydrate decomposition, carbon storage, and leachate toxicity. Tests were conducted in triplicate 8 L reactors operated to obtain maximum yields. Measured methane yields for red oak, eucalyptus, spruce, radiata pine, plywood (PW), oriented strand board (OSB) from hardwood (HW) and softwood (SW), particleboard (PB) and medium-density fiberboard (MDF) were 32.5, 0, 7.5, 0.5, 6.3, 84.5, 0, 5.6, and 4.6 mL CH(4) dry g(-1), respectively. The red oak, a HW, exhibited greater decomposition than either SW (spruce and radiata), a trend that was also measured for the OSB-HW relative to OSB-SW. However, the eucalyptus (HW) exhibited toxicity. Thus, wood species have unique methane yields that should be considered in the development of national inventories of methane production and carbon storage. The current assumption of uniform biodegradability is not appropriate. The ammonia release from urea formaldehyde as present in PB and MDF could contribute to ammonia in landfill leachate. Using the extent of carbon conversion measured in this research, 0-19.9%, predicted methane production from a wood mixture using the Intergovernmental Panel for Climate Change waste model is only 7.9% of that predicted using the 50% carbon conversion default. PMID:21749061

  8. Biodegradation of glycol ethers in soil

    SciTech Connect

    Gonsior, S.J.; West, R.J.

    1995-08-01

    Because of the widespread use of glycol ethers in applications ranging from consumer products to use as chemical intermediates, there is a need to better understand the fate of these compounds in the environment. Soil biodegradation studies were conducted for three propylene glycol ethers: 1-methoxy-2-propanol, 1-phenoxy-2-propanol, and 1-methoxy-2-propanol acetate. The test compounds were labeled with carbon-14 at either the methoxy or phenoxy substituents. Biodegradation of the three compounds was observed in two sandy loam soils. The time required for disappearance of 50% of the test compounds ranged from < 1 d at 0.2 ppm (w/w) to <7 d at 107 ppm. Degradation rates were slower in a sandy soil, reflecting the lower concentration of microorganisms present. No significant accumulation of intermediate products was observed, and ultimate yields of {sup 14}CO{sub 2} were in the range of 40 to 65% of the initial concentration. Results indicated that the glycol ethers were degraded in a variety of soils under aerobic conditions.

  9. Oxidation and biodegradation of polyethylene films containing pro-oxidantadditives: Synergistic effects of sunlight exposure, thermal aging and fungal biodegradation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synergistic effects of sunlight exposure, thermal aging and fungal biodegradation on the oxidation and biodegradation of linear low density poly (ethylene) PE-LLD films containing pro-oxidant were examined. To achieve oxidation and degradation, films were first exposed to the sunlight for 93 days du...

  10. Biodegradable copolymers carrying cell-adhesion peptide sequences.

    PubMed

    Proks, Vladimír; Machová, Lud'ka; Popelka, Stepán; Rypácek, Frantisek

    2003-01-01

    Amphiphilic block copolymers are used to create bioactive surfaces on biodegradable polymer scaffolds for tissue engineering. Cell-selective biomaterials can be prepared using copolymers containing peptide sequences derived from extracellular-matrix proteins (ECM). Here we discuss alternative ways for preparation of amphiphilic block copolymers composed of hydrophobic polylactide (PLA) and hydrophilic poly(ethylene oxide) (PEO) blocks with cell-adhesion peptide sequences. Copolymers PLA-b-PEO were prepared by a living polymerisation of lactide in dioxane with tin(II)2-ethylhexanoate as a catalyst. The following approaches for incorporation of peptides into copolymers were elaborated. (a) First, a side-chain protected Gly-Arg-Gly-Asp-Ser-Gly (GRGDSG) peptide was prepared by solid-phase peptide synthesis (SPPS) and then coupled with delta-hydroxy-Z-amino-PEO in solution. In the second step, the PLA block was grafted to it via a controlled polymerisation of lactide initiated by the hydroxy end-groups of PEO in the side-chain-protected GRGDSG-PEO. Deprotection of the peptide yielded a GRGDSG-b-PEO-b-PLA copolymer, with the peptide attached through its C-end. (b) A protected GRGDSG peptide was built up on a polymer resin and coupled with Z-carboxy-PEO using a solid-phase approach. After cleavage of the delta-hydroxy-PEO-GRGDSG copolymer from the resin, polymerisation of lactide followed by deprotection of the peptide yielded a PLA-b-PEO-b-GRGDSG block copolymer, in which the peptide is linked through its N-terminus. PMID:12903721