|Tuesday, August 25|
Bioabsorption, Healing, and Biocompatibility of BioMg ®250 in a Canine Mandible Osteotomy Model
* Raymond Decker, nanoMAG, United States
A preclinical Craniomaxillofacial (CMF) mandible research study is being performed on 76 mature canines and intermediate results are reported- comparing novel bioabsorbable Magnesium alloy BioMG 250 to Titanium plates and screws. BioMg 250 is microalloyed with nutrient elements Zn, Ca and Mn to harden the alloy with nanometer-sized transition nanostructures. Radiography, µCT, histology and mechanical bend strength observations were made out to 26 weeks of exposure. As predicted by in vitro corrosion tests, the in vivo bioabsorption rate of BioMg 250 was moderate, even without coating. Osteotomy healing was faster by BioMg 250 than by Ti, whereas biocompatibility and residual mechanical properties were comparable.
Nano-micrometer surface roughness gradients reveal topographical influences on differentiating responses of vascular cells on biodegradable magnesium
* Ke Zhou, Shanghai Jiao Tong University, China
Yutong Li, Shanghai Jiao Tong University, China
Guangyin Yuan, Shanghai Jiao Tong University, China
Jinyun Tan, Huashan Hospital, Fudan University, China
Jia Pei, Shanghai Jiao Tong University, China
Distinctively directing endothelial cells (ECs) and smooth muscle cells (SMCs), potentially by surface topography cue, is of central importance for enhancing bioefficacy of vascular implants. For the first time, surface gradients with a broad range of nano-micrometer roughness are developed on Mg, a promising next-generation biodegradable metal, to carry out systematic study on the response of ECs and SMCs. Cell adhesion, spreading and proliferation are quantified along gradients by high-throughput imaging, illustrating drastic divergence between ECs and SMCs, especially at highly rough region. The profound role of surface topography overcoming the biochemical cue of released Mg2+ is unraveled at different roughness ranges for ECs and SMCs. Further insights into the underlying regulatory mechanism are gained at subcellular and gene level. Our work enables high-efficient exploration of optimized surface morphology for modulating favored cell selectivity of promoting ECs and suppressing SMCs, providing a potential strategy to achieve rapid endothelialization for Mg.
MAGNESIUM REGULATES CELL PROLIFERATION: A FUZZY CELLULAR AUTOMATA MODELING APPROACH
* Jalil Nourisa, HZG, Germany
Berit Zeller-Plumhoff, HZG, Germany
Heike Helmholz, HZG, Germany
Berengere Luthringer-Feyerabend, HZG, Germany
Regine Willumeit-Römer, HZG, Germany
Several cell culture experiments have shown the regulatory effect of Magnesium (Mg) on cell proliferation. This study aims at developing a knowledge-based computer model that captures the dynamics of cell proliferation in response to Mg extracts. The model offers a platform to quantitatively study the impact of Mg on cellular processes in tandem with other determinant factors such as pH.
Biodegradable Magnesium Screw for Fixation of Barrier Membranes in Guided Bone Regeneration
* Frank Witte, Charite - Universitätsmedizin Berlin, biotrics bioimplants AG, Germany
A biodegradable magnesium screw made of the magnesium alloy WZM211 with a MgF2 coating was designed to fulfill all of the key properties required for an ideal fixation screw of membranes used in guided bone (GBR) and guided tissue regeneration (GTR) surgeries.
Biodegradable Magnesium Barrier Membrane Used for Guided Bone Regeneration in Dental Surgery
* Frank Witte, Charite - Universitätsmedizin Berlin, biotrics bioimplants AG, Germany
A magnesium barrier membrane will be presented as an alternative resorbable membrane to be used in GBR surgeries.
The use of resorbable metals in clinical point-of-care manufacturing: Distributed manufacturing during and after the era of COVID-19
* David Dean, The Ohio State University, United States
Alan Luo, The Ohio State University, United States
Michael Groeber, The Ohio State University, United States
Glenn Daehn, The Ohio State University, United States
The ways in which resorbable metal alloys can be used in clinical point of care manufacturing will begin with establishing methods of authenticating material composition, alloying quality, and desired mechanical, biocompatibility, and resorption (corrosion) properties of as cast or atomized powders.
Cells response to topologically ordered Mg scaffolds modified with direct plasma nanosynthesis
* Viviana Marcela Posada Perez, Universidad Nacional de Colombia, Colombia
Juan Fernando Ramírez , Universidad Nacional de Colombia, Colombia
Patricia Fernández-Morales , Universidad Pontificia Bolivariana , Colombia
Jean Paul Allain, Pennsylvania State University, United States
Mg-based scaffolds with customized micro-geometry represent an opportunity to mimic the structural and mechanical characteristics of bone. However, the increase in the exposed area compromises the corrosion rate of the material. In a complex structure, surface modification alternatives such coatings could affect the structural and geometrical characteristics of the material and are hindered by their restricted adhesive properties. Hence, in the present work, direct plasma nanosynthesis (DPNS) is introduced for topologically ordered Mg scaffolds. A multi-functional interface was designed based on the evolution of well-ordered nanostructures on the outer surface and Al segregation driven by low-energy Ar+ irradiation on the subsurface adjacent to the bulk material. The resultant surface was able to protect the scaffold from fast corrosion due to the formation of Ca-phosphates, which in turn increased the bioactivity of the material.
Does play the place of Hydrogen evolution during degradation of Mg or Mg alloys a special role for interpretation of degradation reactions
* Wolf-Dieter Mueller, Charite Universitätsmedizin Berlin, Germany
Yuqiuhan Zhang, Charite Universitätsmedizin Berlin, Germany
Tycho Zimmermann, Charite Universitätsmedizin Berlin, Germany
Florian Beuer, Charite Universitätsmedizin Berlin, Germany
Does play the place of Hydrogen evolution during degradation of Mg or Mg alloys a special role for interpretation of degradation reactions. Therefore, HER spots onto XHP Mg, pure Mg and AgxMg alloys will be observed during OCP and CV loadings in two various solutions, HBSS and MEM, using the MCS coupled with a flow chamber under a video microscope. Based on the pictures at different times of the loading cycles the electro-chemical data and the hydrogen evolution spots and positions are compared. It will be tried to explain if there are an interesting influence onto the degradation or not.
Exploring the effects of enzymes on the corrosion behavior of Mg-Zn alloy wires in simulated gastrointestinal fluids
* Yue Zhang, Southeast University, China
Feng Xue, Southeast University, China
Chenglin Chu, Southeast University, China
Jing Bai, Southeast University, China
In recent years, there has been an up-surge interest in the potential use of magnesium (Mg) alloys for gastrointestinal anastomosis. The healing time of gastrointestinal tissue is just needed for several weeks, which is expected to match the degradation rate of Mg alloys devices. It is well recognized those inorganic species govern the degradation behaviour of Mg alloys in biological conditions to a great degree, but in the meanwhile, the effect of organic compounds on the degradation of Mg alloys cannot be negligible. The digestive enzymes are the crucial parts of the whole digestive process. Therefore, it is of great significance to study the role of enzymes for acquiring the laws of degradation behaviour of Mg alloys.
Mechanical property and biocompatibility of binary zinc alloys
* Yingchao Su, Stony Brook University, United States
Donghui Zhu, Stony Brook University, United States
Zinc (Zn) has been recently proposed as a novel biodegradable metal thanks to its essential physiological and biological roles and its promising in vivo degradation rate [1, 2]. Compared to Mg alloys and Fe alloys, the degradation behaviour of Zn alloys is more likely in line with clinical demand. One of the main factors limiting the extensive clinical application of Zn and its alloys is their lower mechanical strength. Another concern about Zn as degradable metals is its local and systemic toxicity . Thus, several beneficial alloying elements were used, and the resulting alloys were tested for mechanical and biocompatibility analysis. Collectively, these data clearly illustrate the good mechanical property and biocompatibility of these Zn based alloys, which provide various choices as biodegradable implant materials for different tissue regeneration and repair.