Co-reporter:Yingqi Chen;Xuan Zhang;Sheng Zhao;Manfred F. Maitz;Wentai Zhang;Su Yang;Jinlong Mao;Nan Huang
Journal of Materials Chemistry B 2017 vol. 5(Issue 22) pp:4162-4176
Publication Date(Web):2017/06/07
DOI:10.1039/C6TB03157A
Heparin (Hep) or bivalirudin (BVLD) were immobilized in an organic phytic acid (PA) coating on Mg by an in situ chemical route. Such a drug-loaded PA coating was designed to enhance both corrosion control and biocompatibility. It was found that both Hep- and BVLD-loaded PA coatings exhibited a dual role in effectively controlling corrosion as well as providing a biofunctional effect. Experiments involving electrochemical corrosion and in vitro degradation by immersion revealed that PA&Hep- and PA&BVLD-coated Mg had the same effect or even slower corrosion/degradation in phosphate buffered saline compared to PA-coated Mg, and it degraded significantly slower than untreated Mg. Moreover, Hep- or BVLD-loaded PA coatings showed relatively good hemocompatibility, with a prolonged clotting time, inhibited platelets adhesion as well as reduced hemolysis compared to untreated Mg. In addition, both PA&Hep and PA&BVLD coatings promoted endothelial cells growth and restrained the proliferation of smooth muscle cells. In vivo assays indicated that PA&Hep-coated Mg exhibited a significant difference in mass loss compared to untreated Mg, as well as better histocompatibility than other samples. These results demonstrate that our coating strategy shows a great potential in surface modification of biodegradable Mg. Finally, the mechanism for the incorporation of the drugs into the PA coating is discussed from both theoretical and practical perspectives.
Co-reporter:Yingqi Chen, Wentai Zhang, Manfred F. Maitz, Meiyun Chen, Heng Zhang, Jinlong Mao, Yuancong Zhao, Nan Huang, Guojiang Wan
Corrosion Science 2016 Volume 111() pp:541-555
Publication Date(Web):October 2016
DOI:10.1016/j.corsci.2016.05.039
•Corrosion behavior of Zn with Fe and Mg in immersion degradation course acquired.•The transient electrochemical corrosion results of Zn lie between Fe and Mg.•Nonetheless, Zn corroded faster than Fe and Mg in long-term immersion degradation.•Such degradation profile is due to localized corrosion mode and products changing.•Distinction must be drawn between its transient assay and long-term results.The corrosion behavior of Zn was compared with those of Fe and Mg in a long-term course of immersing in phosphate buffered saline (PBS) as biodegradable metal for bio-implants application. The comparison focused on corrosion rate, mode, products and surface characteristics along the immersion degradation up to 21 days. For transient assays, the open circuit potential and corrosion rate placed Zn between Fe and Mg. However, in a long-term course the corrosion rate of Zinc developed faster than Fe and Mg. This was ascribed to its unique localized corrosion and corrosion products changing in contrast to Fe and Mg.
Co-reporter:Meiyun Chen, Yingqi Chen, Wentai Zhang, Sheng Zhao, Juan Wang, Jinlong Mao, Wei Li, Yuancong Zhao, Nan Huang and Guojiang Wan
RSC Advances 2016 vol. 6(Issue 18) pp:15247-15259
Publication Date(Web):22 Jan 2016
DOI:10.1039/C5RA23228G
An ultrathin bisphosphonate film, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), was deposited on magnesium for biodegradable implant applications. The small, bioactive HEDP molecule is supposed to be not only bio-safe, but also favorable for creating a highly protective layer for the control of the corrosion/degradation of Mg. In an in situ chemical sequence, the HEDP molecules were covalently surface-immobilized on the alkaline pretreated Mg and then spontaneously deposited by participation in a chelating reaction with Mg ions. An organometallic-like compound layer was thus formed, which was ascertained to be within the nanoscale and complied well with the substrate. The tape test showed that the HEDP film provides excellent adhesion strength. Electrochemical corrosion and in vitro immersion degradation investigations demonstrated that the HEDP coated Mg exhibited significantly slower corrosion rate than untreated Mg in phosphate buffered saline (PBS) solution. Of particular significance is the observation that HEDP coated Mg presented a remarkably suppressed localized corrosion mode. The meliorated corrosion/degradation behavior is credited to both the nature of the organometallic-like HEDP derivative layer, as well as the high quality of the film, with respect to compactness and homogeneity. Our HEDP modified Mg may bode well for application in biodegradable implants.
Co-reporter:Yingqi Chen, Sheng Zhao, Meiyun Chen, Wentai Zhang, Jinlong Mao, Yuancong Zhao, Manfred F. Maitz, Nan Huang, Guojiang Wan
Corrosion Science 2015 Volume 96() pp:67-73
Publication Date(Web):July 2015
DOI:10.1016/j.corsci.2015.03.020
•A polydopamine (PDA) layer was inserted into TiO2 coated Mg.•The sandwiched PDA/TiO2 coated Mg achieved significantly low corrosion current density icorr.•The sandwiched PDA/TiO2 coated Mg exhibited remarkably suppressed in vitro degradation rate.•The sandwiched PDA hinders effectively the electrical pathway of galvanic corrosion cell.•Such kinetic strategy promises a new route for corrosion-control of extremely active magnesium.A polydopamine (PDA) layer was sandwiched between a TiO2 coating and Mg substrate to enhance the corrosion protection. The PDA layer was covalently immobilized on Mg, and the TiO2 was coated by liquid phase deposition subsequently on it. The hybrid TiO2/PDA coated Mg exhibited significantly smaller free corrosion current density as well as a remarkably lower degradation rate in vitro (up to 21 days) in phosphate buffered saline compared to direct TiO2 coated and untreated Mg. The efficacy is ascribed to the organic PDA layer which suppresses the electric pathway of galvanic corrosion cell and therefore corrosion rate of magnesium.
Co-reporter:Sheng Zhao;Yingqi Chen;Bo Liu;Meiyun Chen;Jinlong Mao;Hairuo He;Yuancong Zhao;Nan Huang
Journal of Biomedical Materials Research Part A 2015 Volume 103( Issue 5) pp:1640-1652
Publication Date(Web):
DOI:10.1002/jbm.a.35301
ABSTRACT
Magnesium as well as its alloys appears increasingly as a revolutionary bio-metal for biodegradable implants application but the biggest challenges exist in its too fast bio-corrosion/degradation. Both corrosion-controllable and bio-compatible Mg-based bio-metal is highly desirable in clinic. In present work, hexamethylenediaminetetrakis (methylenephosphonic acid) [HDTMPA, (H2O3P−CH2)2−N−(CH2)6−N−(CH2−PO3H2)2], as a natural and bioactive organic substance, was covalently immobilized and chelating-deposited onto Mg surface by means of chemical conversion process and dip-coating method, to fullfill dual-task performance of corrosion-protective and osteo-compatible functionalities. The chemical grafting of HDTMPA molecules, by participation of functional groups on pretreated Mg surface, ensured a firmly anchored base layer, and then sub-sequential chelating reactions of HDTMPA molecules guaranteed a homogenous and dense HDTMPA coating deposition on Mg substrate. Electrochemical corrosion and immersion degradation results reveal that the HDTMPA coated Mg provides a significantly better controlled bio-corrosion/degradation behavior in phosphate buffer saline solution as compared with untreated Mg from perspective of clinic requirement. Moreover, the HDTMPA coated Mg exhibits osteo-compatible in that it induces not only bioactivity of bone-like apatite precipitation but also promotes osteoblast cells adhesion and proliferation. Our well-controlled biodegradable and biocompatible HDTMPA modified Mg might bode well for next generation bone implant application. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1640–1652, 2015.
Co-reporter:Yingqi Chen, Sheng Zhao, Bo Liu, Meiyun Chen, Jinlong Mao, Hairuo He, Yuancong Zhao, Nan Huang, and Guojiang Wan
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 22) pp:19531
Publication Date(Web):November 3, 2014
DOI:10.1021/am506741d
Biodegradable, a new revolutionary concept, is shaping the future design of biomedical implants that need to serve only as a temporary scaffold. Magnesium appears to be the most promising biodegradable metal, but challenges remain in its corrosion-controlling and uncertain biocompatibility. In this work, we employ chemical conversion and alternating dip-coating methods to anchor and deposit an Mg ion-integrated phytic acid (Mg-PA) coating on Mg, which is supposed to function both corrosion-controlling and osteo-compatible. It was ascertained that PA molecules were covalently immobilized on a chemically converted Mg(OH)2 base layer, and more PA molecules were deposited subsequently via chelating reactions with the help of additive Mg ions. The covalent immobilization and the Mg ion-supported chelating deposition contribute to a dense and homogeneous protective Mg-PA coating, which guarantees an improved corrosion resistance as well as a reduced degradation rate. Moreover, the Mg-PA coating performed osteo-compatible to promote not only bioactivity of bonelike apatite precipitation, but also induced osteoblast cells adhesion and proliferation. This is ascribed to its nature of PA molecule and the biocompatible Mg ion, both of which mimic partly the compositional structure of bone. Our magnesium ion-integrated PA-coated Mg might bode well for the future of biodegradable bone implant application.Keywords: biodegradable metals; bone implants; corrosion; magnesium; osteo-biocompatibility; phytic acid
Co-reporter:Juan Wang, Yonghui He, Manfred F. Maitz, Boyce Collins, Kaiqin Xiong, Lisha Guo, Yeoheung Yun, Guojiang Wan, Nan Huang
Acta Biomaterialia 2013 Volume 9(Issue 10) pp:8678-8689
Publication Date(Web):November 2013
DOI:10.1016/j.actbio.2013.02.041
Abstract
Biodegradable magnesium-based materials have a high potential for cardiovascular stent applications; however, there exist concerns on corrosion control and biocompatibility. A surface-eroding coating of poly(1,3-trimethylene carbonate) (PTMC) on magnesium (Mg) alloy was studied, and its dynamic degradation behavior, electrochemical corrosion, hemocompatibility and histocompatibility were investigated. The PTMC coating effectively protected the corrosion of the Mg alloy in the dynamic degradation test. The corrosion current density of the PTMC-coated alloy reduced by three orders and one order of magnitude compared to bare and poly(ε-caprolactone) (PCL)-coated Mg alloy, respectively. Static and dynamic blood tests in vitro indicated that significantly fewer platelets were adherent and activated, and fewer erythrocytes attached on the PTMC-coated surface and showed less hemolysis than on the controls. The PTMC coating after 16 weeks’ subcutaneous implantation in rats maintained ∼55% of its original thickness and presented a homogeneously flat surface demonstrating surface erosion, in contrast to the PCL coated control, which exhibited non-uniform bulk erosion. The Mg alloy coated with PTMC showed less volume reduction and fewer corrosion products as compared to the controls after 52 weeks in vivo. Excessive inflammation, necrosis and hydrogen gas accumulation were not observed. The homogeneous surface erosion of the PTMC coating from exterior to interior (surface-eroding behavior) and its charge neutral degradation products contribute to its excellent protective performance. It is concluded that PTMC is a promising candidate for a surface-eroding coating applied to Mg-based implants.
Co-reporter:Dong Xie, Guojiang Wan, Manfred F. Maitz, Hong Sun, Nan Huang
Surface and Coatings Technology 2013 Volume 214() pp:117-123
Publication Date(Web):15 January 2013
DOI:10.1016/j.surfcoat.2012.11.012
Mechanical and chemical durability is of equal importance as bio-functionality for surface-modifying films on biomedical devices. This is in particular true for those serving on combined conditions of loading and a corrosive ambient. In this work, we investigated the deformation and corrosion behaviors of Ti–O films coated onto 316L stainless steel aimed for cardiovascular stent applications. The Ti–O films were synthesized by plasma immersion ion implantation and deposition (PIII&D), and the investigation conditions were as required for cardiovascular stents concerning plastic deformation and corrosion. Tensile and three point bending tests showed that no peeling and delaminating occurred on the Ti–O film which had undergone relatively high plastic deformation (4% to16% elongation). Electrochemical corrosion tests showed that the deformed PIII&D Ti–O film coated 316L SS suffered more severe corrosion in simulated body fluid (SBF) than the non-deformed, but remained comparable to uncoated 316L SS, which is clinically acceptable for stents. Due to the good mechanical and chemical durability as well as biomedical functionalities, the PIII&D Ti–O films appear promising as surface-modification of cardiovascular stents in real applications.Highlights► Deformation and corrosion behavior of PIII&D Ti–O film deposited 316L SS ► Our Ti–O film can sustain 16% tensile plastic deformation without failures. ► Deformed Ti–O coated 316L SS has increased corrosion, but is clinically acceptable. ► Durability of our Ti–O film reveals its promising feasibility for vascular stents use.
Co-reporter:Guojiang Wan, Alexander A. Solovev, G. S. Huang, Manfred F. Maitz, Nan Huang and Y. F. Mei
Journal of Materials Chemistry A 2012 vol. 22(Issue 26) pp:12983-12987
Publication Date(Web):10 May 2012
DOI:10.1039/C2JM30641G
Dynamic curvature control of rolled-up metal nanomembranes using an active magnesium layer design is implemented in bio-oriented conditions to realize shape transformation of expansion, shrinking, un-rolling and re-rolling. The tube integrated with a catalytic Pt layer is proposed for a new type of smart drug delivery microsystem.
Co-reporter:Dong Xie, Guojiang Wan, Manfred F. Maitz, Yifeng Lei, Nan Huang, Hong Sun
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 2012 Volume 289() pp:91-96
Publication Date(Web):15 October 2012
DOI:10.1016/j.nimb.2012.07.033
Up to date, materials for cardiovascular stents are still far from satisfactory because of high risk of biomaterials-associated restenosis and thrombosis. Extensive efforts have been made to improve the biocompatibility of the materials by various surface modification techniques. Ti–O2−x films prepared by plasma immersion ion implantation and deposition (PIII&D) have shown good blood compatibility. For clinical application, surface quality and mechanical durability of the Ti–O2−x film on stents are also of critical importance for the long-term serving. In this paper we present our research results on surface quality, mechanical investigation and characterization of Ti–O2−x films prepared using PIII&D on stent products provided by Boston Scientific SCIMED. Ti–O2−x films with mostly Rutile and little non-stoichiometric phases were obtained with smoothness of <3 nm RMS, largely homogeneity as well as good intergradient film/substrate interface. The Ti–O2−x films on stents products were sustained balloon-expansion of clinically-required extent without mechanical failure, showing highly potential feasibility for cardiovascular stents application.Highlights► We prepared Ti–O2−x films of good quality by PIII&D successfully on stents product. ► The Ti–O2−x film shows good homogeneity and intergradient film/substrate interface. ► The Ti–O2−x films on stent sustain clinically-required expansion without failure. ► The films show good mechanical durability for cardiovascular stents application.
Co-reporter:Yingqi Chen, Xuan Zhang, Sheng Zhao, Manfred F. Maitz, Wentai Zhang, Su Yang, Jinlong Mao, Nan Huang and Guojiang Wan
Journal of Materials Chemistry A 2017 - vol. 5(Issue 22) pp:NaN4176-4176
Publication Date(Web):2017/05/03
DOI:10.1039/C6TB03157A
Heparin (Hep) or bivalirudin (BVLD) were immobilized in an organic phytic acid (PA) coating on Mg by an in situ chemical route. Such a drug-loaded PA coating was designed to enhance both corrosion control and biocompatibility. It was found that both Hep- and BVLD-loaded PA coatings exhibited a dual role in effectively controlling corrosion as well as providing a biofunctional effect. Experiments involving electrochemical corrosion and in vitro degradation by immersion revealed that PA&Hep- and PA&BVLD-coated Mg had the same effect or even slower corrosion/degradation in phosphate buffered saline compared to PA-coated Mg, and it degraded significantly slower than untreated Mg. Moreover, Hep- or BVLD-loaded PA coatings showed relatively good hemocompatibility, with a prolonged clotting time, inhibited platelets adhesion as well as reduced hemolysis compared to untreated Mg. In addition, both PA&Hep and PA&BVLD coatings promoted endothelial cells growth and restrained the proliferation of smooth muscle cells. In vivo assays indicated that PA&Hep-coated Mg exhibited a significant difference in mass loss compared to untreated Mg, as well as better histocompatibility than other samples. These results demonstrate that our coating strategy shows a great potential in surface modification of biodegradable Mg. Finally, the mechanism for the incorporation of the drugs into the PA coating is discussed from both theoretical and practical perspectives.
Co-reporter:Guojiang Wan, Alexander A. Solovev, G. S. Huang, Manfred F. Maitz, Nan Huang and Y. F. Mei
Journal of Materials Chemistry A 2012 - vol. 22(Issue 26) pp:NaN12987-12987
Publication Date(Web):2012/05/10
DOI:10.1039/C2JM30641G
Dynamic curvature control of rolled-up metal nanomembranes using an active magnesium layer design is implemented in bio-oriented conditions to realize shape transformation of expansion, shrinking, un-rolling and re-rolling. The tube integrated with a catalytic Pt layer is proposed for a new type of smart drug delivery microsystem.
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