scholarly journals Manipulating Air-Gap Electrospinning to Create Aligned Polymer Nanofiber-Wrapped Glass Microfibers for Cortical Bone Tissue Engineering

2020 ◽  
Vol 7 (4) ◽  
pp. 165
Author(s):  
Houston R. Linder ◽  
Austin A. Glass ◽  
Delbert E. Day ◽  
Scott A. Sell
Keyword(s):  
Cell Migration ◽  
Cortical Bone ◽  
Inductively Coupled Plasma ◽  
Air Gap ◽  
Cell Orientation ◽  
Polymer Nanofibers ◽  
Viscoelastic Deformation ◽  
Inductively Coupled ◽  
Polymer Nanofiber ◽  
Scaffold Degradation

Osteons are the repeating unit throughout cortical bone, consisting of canals filled with blood and nerve vessels surrounded by concentric lamella of hydroxyapatite-containing collagen fibers, providing mechanical strength. Creating a biodegradable scaffold that mimics the osteon structure is crucial for optimizing cellular infiltration and ultimately the replacement of the scaffold with native cortical bone. In this study, a modified air-gap electrospinning setup was exploited to continuously wrap highly aligned polycaprolactone polymer nanofibers around individual 1393 bioactive glass microfibers, resulting in a synthetic structure similar to osteons. By varying the parameters of the device, scaffolds with polymer fibers wrapped at angles between 5–20° to the glass fiber were chosen. The scaffold indicated increased cell migration by demonstrating unidirectional cell orientation along the fibers, similar to recent work regarding aligned nerve and muscle regeneration. The wrapping decreased the porosity from 90% to 80%, which was sufficient for glass conversion through ion exchange validated by inductively coupled plasma. Scaffold degradation was not cytotoxic. Encapsulating the glass with polymer nanofibers caused viscoelastic deformation during three-point bending, preventing typical brittle glass fracture, while maintaining cell migration. This scaffold design structurally mimics the osteon, with the intent to replace its material compositions for better regeneration.

scholarly journals Trace element distribution in human cortical bone microstructure: the potential for unravelling diet and social status in archaeological bones

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Kaare Lund Rasmussen ◽  
George R. Milner ◽  
Thomas Delbey ◽  
Lilian Skytte ◽  
Niels Lynnerup ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Social Status ◽  
Trace Element ◽  
Cortical Bone ◽  
Cross Sections ◽  
Inductively Coupled Plasma ◽  
Life Histories ◽  
Bone Microstructure ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry

Abstract Variation in the trace element chemistry of cortical bone microstructure is delineated for interred and non-interred human femora. This was done to investigate the range of element concentrations that might occur within single bones, specifically the original laminar bone and later osteons, and its potential for investigating chemical life histories. To do so, femora were chosen from individuals who experienced quite different ways of life over the past two millennia. The distributions of Sr, Ba, Cu, and Pb, mostly in partial (early) and complete (late) osteons, in cross-sections of proximal femora were characterized through Laser Ablation Inductively Coupled Plasma Mass Spectrometry. Absolute calibrations of these data were obtained using solution Inductively Coupled Plasma Mass Spectrometry on adjacent dissolved bulk samples. Chemical life histories were approximated by classifying bone microstructure into four categories: laminar bone and 1st, 2nd, and 3rd generation osteons. This four-part sequence, on average, charts the temporal dimension of an individual’s life. Consistent with recent studies of medieval bones, Sr and Ba are thought to be mainly responsive to diet, presumably related to the consumption of mostly locally produced food, while Cu and Pb do the same for heavy metal exposure often attributable to social status or occupation. No systematic differences in these elements were found between interred and non-interred individuals. The effect of diagenesis on interpretations of life histories based on archaeological bone, therefore, are minimized by plotting element concentrations across cortical bone cross-sections.

Estimation of Trace Elements in Gingival Crevicular Fluid and Serum-Comparative Study in Healthy and Periodontitis

2017 ◽  
Vol 9 (5) ◽  
Author(s):  
Bhagavathami Meenaksh ◽  
Chitraa R. Chandran ◽  
Aravindhan Thathchari Ranganathan ◽  
Kavindapadi Venkateswaran Rama ◽  
Valarmathy Srinivasan
Keyword(s):  
Trace Elements ◽  
Inductively Coupled Plasma ◽  
Gingival Crevicular Fluid ◽  
Serum Zinc ◽  
Cross Sectional Study ◽  
Serum Copper ◽  
Cross Sectional ◽  
Inductively Coupled ◽  
Significant Difference ◽  
Copper Zinc

Background: This study aims to determine and compare the levels of trace elements copper, zinc, selenium and chromium in GCF and serum of patients with periodontitis and healthy individuals. Methods: This cross sectional study includes 24 study subjects recruited from the patients reporting to the Department of Periodontics , Tagore Dental College Chennai. All the selected patients were subjected to a clinical examination done by a single examiner. The estimation of trace elements Copper, Zinc, Selenium and Chromium in GCF and serum is performed using Perkin Elmer optima 5300 Inductively Coupled Plasma Emission Spectrometer (ICPOES). Results: GCF and serum copper levels showed no significant difference in both periodontitis and healthy groups . Selenium levels tend to be the same in both groups. Serum zinc levels are more in periodontitis patients than healthy subjects (p less than 0.01). GCF chromium levels are found to be more in patients with periodontitis than healthy. Conclusions : More research is therefore needed to monitor the role of these trace elements C with an increased sample size to ascertain whether they are associated with a reduced risk of periodontitis.

Metal-Organic Frameworks vs. Buffers: Case Study of UiO-66 Stability

2020 ◽  
Author(s):  
Daniel Bůžek ◽  
Slavomír Adamec ◽  
Kamil Lang ◽  
Jan Demel
Keyword(s):  
Inductively Coupled Plasma ◽  
Buffer Capacity ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Analytical Techniques ◽  
Aqueous Dispersions ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Metal Organic

<div><p>UiO-66 is a zirconium-based metal-organic framework (MOF) that has numerous applications. Our group recently determined that UiO-66 is not as inert in aqueous dispersions as previously reported in the literature. The present work therefore assessed the behaviour of UiO-66 in buffers: 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIS), 4-(2-hydroxyethyl)piperazine-1-ethane sulfonic acid (HEPES), N-ethylmorpholine (NEM) and phosphate buffer (PB), all of which are commonly used in many UiO-66 applications. High pressure liquid chromatography and inductively coupled plasma mass spectrometry were used to monitor degradation of the MOF. In each buffer, the terephthalate linker was released to some extent, with a more pronounced leaching effect in the saline forms of these buffers. The HEPES buffer was found to be the most benign, whereas NEM and PB should be avoided at any concentration as they were shown to rapidly degrade the UiO-66 framework. Low concentration TRIS buffers are also recommended, although these offer minimal buffer capacity to adjust pH. Regardless of the buffer used, rapid terephthalate release was observed, indicating that the UiO-66 was attacked immediately after mixing with the buffer. In addition, the dissolution of zirconium, observed in some cases, intensified the UiO-66 decomposition process. These results demonstrate that sensitive analytical techniques have to be used to monitor the release of MOF components so as to quantify the stabilities of these materials in liquid environments.</p></div>

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