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degradable magnesium

Xian Tong, Dechuang Zhang, Xiaotuan Zhang, Yingchao Su, Zimu Shi, Kun Wang, Jianguo Lin, Yuncang Li, Jixing Lin, Cuie Wen
Zinc (Zn)-based alloys are considered a new class of biodegradable implant materials due to their superior chemical stability and processability compared to biodegradable magnesium (Mg) alloys. In this study, we report a new biodegradable Zn-5Ge alloy with highly desirable mechanical, corrosion, and biological properties. Microstructural characterization revealed the effective grain-refining effect of germanium (Ge) on the Zn alloy. Tensile test results indicated that the hot-rolled Zn-5Ge alloy showed an ultimate tensile strength of 237...
October 11, 2018: Acta Biomaterialia
Lumei Liu, Sang-Ho Ye, Xinzhu Gu, Teal Russell, Zhigang Xu, Jagannathan Sankar, William R Wagner, Young-Choon Lee, Yeoheung Yun
Polymeric coatings can provide temporary stability to bioresorbable metallic stents at the initial stage of deployment by alleviating rapid degradation and providing better interaction with surrounding vasculature. To understand this interfacing biocompatibility, this study explored the endothelial-cytocompatibility of polymer-coated magnesium (Mg) alloys under static and dynamic conditions compared to that of non-coated Mg alloy surfaces. Poly (carbonate urethane) urea (PCUU) and poly (lactic-co-glycolic acid) (PLGA) were coated on Mg alloys (WE43, AZ31, ZWEKL, ZWEKC) and 316L stainless steel (316L SS, control sample), which were embedded into a microfluidic device to simulate a vascular environment with dynamic flow...
2018: PloS One
B H Yoo, J C Kim, Y G Kim, D Y Hwang, J H Lee, H G Lee
This study presents the investigation of superconducting joints fabricated using multifilament magnesium diboride (MgB2 ) wires for the development of persistent-current mode magnetic resonance imaging (MRI) magnets. The critical current of the jointed samples decreased with increasing cutting angle because the smaller cutting angle allowed greater exposure of the MgB2 filament, thereby increasing the contact area for the wire-bulk-wire connection. In addition, an appropriate pressing pressure (300 MPa) was necessary to establish the multifilament MgB2 joint without significant degradation of superconducting properties...
September 2018: Review of Scientific Instruments
Yiqun Zhang, Wei Yu, Zhaoyu Ba, Shusen Cui, Jie Wei, Hong Li
Background: Due to the increasing number of patients with bone defects, bone nonunion and osteo-myelitis, tumor and congenital diseases, bone repair has become an urgent problem to be solved. Methods: In this study, the 3D-printed scaffolds of ternary composites containing mesoporous bioglass fibers of magnesium calcium silicate (mMCS), gliadin (GA) and polycaprolactone (PCL) were fabricated using a 3D Bioprinter. Results: The compressive strength and in vitro degradability of the mMCS/GA/PCL composites (MGPC) scaffolds were improved with the increase of mMCS content...
2018: International Journal of Nanomedicine
Yuehua Zhou, Xing Liu, Nan Huang, Yuping Chen
Phenotype switching is a characteristic response of vascular smooth muscle cells (vSMCs) to the dynamic microenvironment and contributes to all stages of atherosclerotic plaque. Here, we immersed pure magnesium and AZ31 alloy in the completed medium under cell culture condition, applied the resultant leaching extracts to the isolated contractile rat aortic vSMCs and investigated how vSMCs phenotypically responded to the degradation of the magnesium-based stent materials. vSMCs became more proliferative and migratory but underwent more apoptosis when exposed to the degradation products of pure magnesium; while the AZ31 extracts caused less cell division but more apoptosis, thus slowing cell moving and growing...
October 1, 2018: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Rubén Forján, Alfonso Rodríguez-Vila, Beatriz Cerqueira, Emma F Covelo, Purificación Marcet, Verónica Asensio
A large number of studies on the reclamation of mine soils focused on the problem caused by metals and did not explore in depth the issue of nutrients and vegetation after the application of organic materials. The aim of this study was to compare the effect of two treatments made of wastes and vegetated with Brassica juncea L. on the fertility of a settling pond mine soil. The first treatment was compost, biochar, and B. juncea (SCBP) and the second treatment was technosol, biochar, and B. juncea (STBP). This study evaluated the effect of the treatments on the soil nutrient concentrations and fertility conditions in the soil amendment mixtures, after 11 months of greenhouse experiment...
September 27, 2018: Environmental Monitoring and Assessment
Govindaraj Perumal, Boopalan Ramasamy, Maya Nandkumar A, Mukesh Doble
This current study is aimed towards the fabrication of AZ31 magnesium cylindrical mesh cage implant with circular holes for orthopedic applications. This mesh cage is coated with nanocomposite material containing polycaprolactone (PCL), pluronic F127 and nano hydroxyapatite (nHA) by electrospinning process. Morphology and composition were analyzed by various characterization techniques. Controlled degradation and weight loss of the nanocomposite coated samples in 28 days were observed when compared with uncoated samples in SBF (simulated body fluid)...
September 6, 2018: Colloids and Surfaces. B, Biointerfaces
Govindaraj Perumal, Boopalan Ramasamy, A Maya Nandkumar, Mukesh Doble
A novel one-step preparation of magnesium particles and Pluronic F127 incorporated with calcium sulfate hemihydrate (CSH) and nano-hydroxyapatite (nHA) ready to use injectable or moldable beads was developed for bone tissue regeneration applications. The nanocomposite showed setting time less than 15 min, very good injectability (75-85%) and good mechanical strength (52-80 MPa). Samples immersed in SBF showed controlled degradation (40-45% reduction in weight) in 28 days. The nanocomposite bone graft was cytocompatible against MG63 osteosarcoma cells and increased the osteogenic gene expression by 2-3 folds...
August 9, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Qiandi Wang, Weijun Zhang, Zhaoyi Yang, Qiongying Xu, Peng Yang, Dongsheng Wang
Anaerobic digestion (AD) has been widely used in sludge treatment for biogas recovery, organic fraction stabilization, and sludge reduction. However, after AD, sludge filterability is extremely deteriorated due to the release of biopolymers and the formation of fine particles. AD sludge is generally rich in nutrients, mainly ammonium nitrogen and phosphates, that result from biopolymer degradation. We designed a conditioning process that combines the in-situ crystallization of magnesium ammonium phosphate (MAP), as a skeleton builder, with organic polymer flocculation...
September 6, 2018: Water Research
Yun Zhao, Bei Liu, Hongwei Bi, Jinjun Yang, Wei Li, Hui Liang, Yue Liang, Zhibin Jia, Shuxin Shi, Minfang Chen
In this study, composite films of stearic acid⁻modified magnesium oxide whiskers (Sa⁻w-MgO)/poly-l-lactic acid (PLLA) were prepared through solution casting, and the in vitro degradation properties and cytocompatibility of the composites with different whisker contents were investigated. The results showed that the degradation behavior of the composite samples depended significantly on the whisker content, and the degradation rate increased with the addition of MgO content. Furthermore, the degradation of the composites with higher contents of whiskers was influenced more severely by the hydrophilicity and pH value, leading to more final weight loss, but the decomposition rate decreased gradually...
September 13, 2018: International Journal of Molecular Sciences
Limin Ren, Kun Yu, Yisong Tan
A magnetoelastic-based (MB) sensor was employed as a novel method to monitor and assess the degradation rate of magnesium-based artificial bone (MBAB) in vitro, which can be used as an implant to repair a bone defect, providing a quantitative method to depict the degradation rate of MBAB. MBABs were fabricated by the Pro/Engineering software and a precision machine tool using high-purity (HP) magnesium. The MB sensor was embedded in the neutral surface of MBAB by an unharmful quick adhesive, forming the MB sensor-embedded MBAB (EMBAB)...
September 12, 2018: Sensors
Nadja Kröger, Alexander Kopp, Mareike Staudt, Mihaela Rusu, Alexander Schuh, Elisa A Liehn
Percutaneous transluminal coronary angioplasty and subsequent vascular scaffold implantation remains the prevalent invasive treatment of coronary heart disease. In-stent restenosis remained a problem with bare metal stents, until drug-eluting stents were introduced. The inhibition of the healing process by the antimitotic drug coating and the permanent metallic remnant can promote sub-acute and delayed stent thrombosis. Thus, the development of biodegradable stents emerged as a subject of research. Magnesium-based bioabsorbable devices can provide sufficient radial force in the acute phase of vessel-treatment and degrade thoroughly in aqueous environment, making them potential new candidates for vascular scaffold applications...
November 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Xue-Nan Gu, Yun Lu, Fan Wang, Wenting Lin, Ping Li, Yubo Fan
Magnesium alloys have gained great attention as biodegradable materials for stent applications. Cardiovascular stents are continuously exposed to different types of mechanical loadings simultaneously during service, including tensile, compressive and fluid shear stress. In this study, the in vitro degradation of WE43 wires was investigated under combined effect of tensile loading and fluid shear stress and compared with that experienced an individual loading condition. For the individual mechanical loading treatment, the degradation of magnesium wires was more severely affected by tensile loading than fluid shear stress...
December 2018: Bioactive Materials
Ling-Yu Li, Lan-Yue Cui, Rong-Chang Zeng, Shuo-Qi Li, Xiao-Bo Chen, Yufeng Zheng, M Bobby Kannan
Magnesium (Mg) and its alloys have become a research frontier in biodegradable materials owing to their superior biocompatibility and excellent biomechanical compatibility. However, their high degradation rate in the physiological environment should be well tackled prior to clinical applications. This review summarizes the latest progress in the development of polymeric coatings on biodegradable Mg alloys over the last decade, regarding preparation strategies for polylactic acid (PLA), poly (latic-co-glycolic) acid (PLGA), polycaprolactone (PCL), polydopamine (PDA), chitosan (CS), collagen (Col) and their composite, and their performance in terms of corrosion resistance and biocompatibility...
August 25, 2018: Acta Biomaterialia
Yifeng Sheng, Li Tian, Chi Wu, Ling Qin, To Ngai
Magnesium (Mg)-based biometals are increasingly becoming a promising candidate of the next-generation implantable materials due to their unique properties, such as high biocompatibility, favorable mechanical strength, and good biodegradability in physiological conditions. However, the swift corrosion of Mg, resulting in early loss of structural support, has posed an enormous challenge in clinical application of Mg-based implants. To overcome these limitations, herein we developed a novel method, which combines the traditional dip-coating with nonsolvent induced phase separation (NIPS), to fabricate biodegradable PLLA coatings with controlled membrane morphology on pure Mg rods...
September 11, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Carola Schröder, Christin Burkhardt, Philip Busch, Georg Schirrmacher, Jörg Claren, Garabed Antranikian
From a biogas reactor metagenome an ORF (bp_cel9A) encoding a bacterial theme C glycoside hydrolase family 9 (GH9) enzyme was recombinantly produced in E. coli BL21 pQE-80L. BP_Cel9A exhibited ≤ 55% identity to annotated sequences. Subsequently, the enzyme was purified to homogeneity by affinity chromatography. The endo-beta-glucanase BP_Cel9A hydrolyzed the beta-1,3-1,4-linked barley beta-glucan with 24 U/mg at 30 °C and pH 6.0. More than 62% of activity was measured between 10 and 40 °C. Lichenan and xyloglucan were hydrolyzed with 67% and 40% of activity, respectively...
October 2018: Protein Journal
Oscar van Mastrigt, Elisa Di Stefano, Sylviani Hartono, Tjakko Abee, Eddy J Smid
BACKGROUND: Important industrial traits have been linked to plasmids in Lactococcus lactis. RESULTS: The dairy isolate L. lactis subsp. lactis biovar diacetylactis FM03P was sequenced revealing the biggest plasmidome of all completely sequenced and published L. lactis strains up till now. The 12 plasmids that were identified are: pLd1 (8277 bp), pLd2 (15,218 bp), pLd3 (4242 bp), pLd4 (12,005 bp), pLd5 (7521 bp), pLd6 (3363 bp), pLd7 (30,274 bp), pLd8 (47,015 bp), pLd9 (15,313 bp), pLd10 (39,563 bp), pLd11 (9833 bp) and pLd12 (3321 bp)...
August 17, 2018: BMC Genomics
Paridhi Gulati, Devin J Rose
Great Northern beans (GNB) contain appreciable magnesium (Mg), potassium (K), phosphorus (P), and iron (Fe), together with the heat-labile vitamin, folate, and the anti-nutritional compound phytate. Thus, the objective was to increase dialyzability of essential mineral elements while degrading phytate and minimizing destruction of folate through extrusion of GNB. Extrusion resulted in significant (p < 0.05) increases in dialyzability of Mg, P, K, and Fe by as much as 50%, 30%, 5%, and 79%, respectively, while decreasing cadmium (Cd) dialyzability...
December 15, 2018: Food Chemistry
N G Grün, P Holweg, S Tangl, J Eichler, L Berger, J J J P van den Beucken, J F Löffler, T Klestil, A M Weinberg
Fracture treatment in children needs new implant materials to overcome disadvantages associated with removal surgery. Magnesium-based implants constitute a biocompatible and bioresorbable alternative. In adults and especially in children, implant safety needs to be evaluated. In children the bone turnover rate is higher and implant material might influence growth capacity, and the long-term effect of accumulated particles or ions is more critical due to the host's prolonged post-surgery lifespan. In this study we aimed to investigate the degradation behavior of ZX00 (Mg-0...
September 15, 2018: Acta Biomaterialia
Sang-Ho Ye, Yingqi Chen, Zhongwei Mao, Xinzhu Gu, Venkat Shankarraman, Yi Hong, Vesselin Shanov, William R Wagner
Degradable metallic stents, most commonly composed of Mg-based alloys, are of interest as an alternative to traditional metallic stents for application in cardiac and peripheral vasculature. Two major design challenges with such stents are control of the corrosion rate and acute presentation of a nonthrombogenic surface to passing blood. In this study, several types of sulfobetaine (SB)-bearing biodegradable polyurethanes were developed and assessed as physical, chemical, and combination-type coatings for a model degradable Mg alloy, AZ31...
August 15, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
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