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71.
Martin Koller Aid Atlić Yolanda Gonzalez-Garcia Christoph Kutschera Gerhart Braunegg 《Macromolecular Symposia》2008,272(1):87-92
Summary: The potential of three different microbial wild type strains as polyhydroxyalkanoate (PHA) producers from whey lactose is compared. Homopolyester and co-polyester biosynthesis was investigated by the archaeon Haloferax mediterranei and the eubacterial strains Pseudomonas hydrogenovora and Hydrogenophaga pseudoflava. H. mediterranei accumulated 50 wt.-% of poly-3-(hydroxybutyrate-co-6%-hydroxyvalerate) in cell dry mass from hydrolyzed whey without addition of 3-hydroxyvalerate (3HV) precursors (specific productivity qp: 2.9 mg/g h). Using P. hydrogenovora, the final percentage of poly-3-hydroxybutyrate (PHB) amounted to 12 wt.-% (qp: 0.03 g/g h); co-feeding of valeric acid resulted in the production of 12 wt.-%. P-3(HB-co-21%-HV) (qp: 0.02 g/g h). With H. pseudoflava, it was possible to reach 40 wt.-% P-3 (HB-co-5%-HV) on not-hydrolyzed whey lactose plus valeric acid as 3HV precursor (qp: 9.1 mg/g h); on hydrolyzed whey lactose without addition of valeric acid, the strain produced 30 wt.-% of PHB (qp: 0.16 g/g h). The characterization of the isolated biopolyesters completes the study. 相似文献
72.
Enhanced biocompatibility of ZnS:Mn quantum dots encapsulated with Aloe vera extract for therapeutic applications 下载免费PDF全文
Toxicity of nanoparticles remains to be a major issue in their application to the biomedical field. Aloe vera(AV) is one of the most widely exploited medicinal plants that have a multitude of amazing properties in the field of medicine.Methanol extract of Aloe vera can be used as a novel stabilising agent for quantum dots to reduce toxicity. We report the synthesis, structural characterization, antibacterial activity and cytotoxicity studies of ZnS:Mn quantum dots synthesized by the colloidal precipitation method, using methanol extract of Aloe vera(AVME) as the capping agent. The ZnS:Mn quantum dots capped with AVME exhibit superior performances in biocompatibility and antibacterial activity compared with ZnS:Mn quantum dots without encapsulation. 相似文献
73.
《Macromolecular bioscience》2017,17(5)
Natural and synthetic cross‐linked polymers allow the improvement of cytocompatibility and mechanical properties of the individual polymers. In osteochondral lesions of big size it will be required the use of scaffolds to repair the lesion. In this work a borax cross‐linked scaffold based on fumarate‐vinyl acetate copolymer and chitosan directed to osteochondrondral tissue engineering is developed. The cross‐linked scaffolds and physical blends of the polymers are analyzed in based on their morphology, glass transition temperature, and mechanical properties. In addition, the stability, degradation behavior, and the swelling kinetics are studied. The results demonstrate that the borax cross‐linked scaffold exhibits hydrogel behavior with appropriated mechanical properties for bone and cartilage tissue regeneration. Bone marrow progenitor cells and primary chondrocytes are used to demonstrate its osteo‐ and chondrogenic properties, respectively, assessing the osteo‐ and chondroblastic growth and maturation, without evident signs of cytotoxicity as it is evaluated in an in vitro system.
74.
Riccardo Levato Miguel A. Mateos‐Timoneda Josep A. Planell 《Macromolecular bioscience》2012,12(4):557-566
PLA MPs are prepared via a novel and toxic‐chemical‐free fabrication route using ethyl lactate, a green solvent and FDA‐approved aroma. MPs are obtained by a solution jet break‐up and solvent displacement method. Adjusting flow parameters allows the tuning of MPs size between 60 and 180 µm, with reduced polydispersity. Morphological analysis shows microporous particles with Janus‐like surface. A fluorophore is successfully loaded into the MPs during their formation step. This versatile green solvent‐based procedure is proven to be suitable for drug encapsulation and delivery applications. The method may be extended to different droplet generation techniques.
75.
A heparin‐like structured macromolecule (HLSM) is synthesized by RAFT polymerization using carboxyl‐terminated trithiocarbonate as the RAFT agent. The HLSM can be directly blended with PES in DMAC to prepare flat‐sheet membrane by means of a liquid–liquid phase separation technique. The synthesized polymeric material retard blood clotting and the modified membrane exhibits good anticoagulant ability due to the existence of the important functional groups ? SO3H, ? COOH and ? OH. The anionic groups on the membrane surface may bind coagulation factors and thus improve anticoagulant ability. The results indicate that the HLSM has potential to improve the anticoagulant properties of biomaterials and to be applied in blood purification including hemodialysis and bioartificial liver supports.
76.
Summary: Stearic acid modified nano hydroxyapatite (n-SHA) filled polyoxymethylene (POM) nanocomposites were prepared by melt mixing method for bone tissue replacement and regeneration applications. Contact angle measurements of POM nanocomposites were carried out to understand the effect of n-SHA addition on the hydrophobicity of nanocomposites. The mechanical properties like tensile strength, Young's modulus and elongation at break were found to be increased significantly by the incorporation of n-SHA into the POM matrix. The bone-bonding ability of the nanocomposites was evaluated by examining the apatite formation on their surface after soaking in simulated body fluid (SBF) and apatite formation was studied by atomic force microscopy (AFM). The protein adhesion studies revealed the enhanced biocompatibility of the nanocomposites due to the presence of n-SHA nanofillers on the surface and it provides favorable binding sites for protein adsorption. The significant improvement in the biocompatibility as well as mechanical, thermal and hydrophobic properties of the POM nanocomposites makes it a potential future material for bone implantation. 相似文献
77.
丝胶基半互穿温敏凝胶的合成及其溶胀行为的研究 总被引:2,自引:0,他引:2
采用半互穿网络技术, 将具有生物相容性的丝胶蛋白(silk sericin)作为第二网络进入聚(N-异丙基丙烯酰胺)(PNIPAM)水凝胶网络中, 在水溶液中制备得到具有半互穿网络结构的丝胶基温敏水凝胶(SS/PNIPAM semi-IPNs). 采用称重法研究了产物的(消)溶胀、温度敏感性、最大溶胀度及脉冲响应行为; 利用扫描电镜(SEM), 差示扫描量热仪(DSC)和动态热机械分析仪(DMA)分别考察了产物的内部形态、热相转变行为和其储能模量随温度的变化. 结果表明: 具有较高亲水性的丝胶蛋白的引入增大了semi-IPNs水凝胶的内部孔径, 导致SS/PNIPAM半互穿水凝胶的溶胀度增加, 并且其储能模量随温度变化更明显. 相比于纯PNIPAM水凝胶, 半互穿水凝胶的消溶胀速率和低临界溶解温度(LCST)变化不大. 相似文献
78.
Yoshiyuki Yokogawa Kaori Nishizawa Fukue Nagata Tetsuya Kameyama 《Journal of Sol-Gel Science and Technology》2001,21(1-2):105-113
Calcium phosphate coating over phosphorylated derivatives of chitin/chitosan material was produced by a process based on phosphorylation, Ca(OH)2 treatment and SBF (simulated body fluid solution) immersion. Chitin/chitosan phosphorylated using urea and H3PO4 and then soaked in saturated Ca(OH)2 solution at ambient temperature, which lead to the formation of thin coatings formed by partial hydrolysis of the PO4 functionalities, were found to stimulate the growth of a calcium phosphate coating on their surfaces after soaking in 1.5 × SBF solution for as little as one day. The Ca(OH)2 treatment facilitates the formation of a calcium phosphate precursor over the phosphorylated chitin/chitosan, which in turn encourages the growth of a calcium deficient apatite coating over the surface upon immersion in SBF solution. The bio-compatibility of calcium phosphate compound—chitin/chitosan composite materials was evaluated by cell culture test using L-929 cells. The initial anchoring ratio and the adhesive strength of L-929 cells for composites was higher than that for the polystyrene disk (LUX, control). The results of in-vitro evaluation suggested that the calcium phosphate—chitin/chitosan composite materials were suitable for cell carrier materials. 相似文献
79.
80.
竺亚斌 《宁波大学学报(理工版)》2001,14(2):77-81
在总结影响材料生物相容性的诸因素基础上,综述了目前世界上用于材料表面化学改性以提高材料的生物相容性的主要方法. 相似文献