scholarly journals Development of Robust Chitosan–Silica Class II Hybrid Coatings with Antimicrobial Properties for Titanium Implants

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 534 ◽  
Author(s):  
Zach Gouveia ◽  
Hiran Perinpanayagam ◽  
Jesse Zhu
Keyword(s):  
Antimicrobial Properties ◽  
Class Ii ◽  
Magic Angle Spinning ◽  
Titanium Implants ◽  
Hybrid Coatings ◽  
Homogeneous Distribution ◽  
Magic Angle ◽  
Coating Materials ◽  
Angle Spinning ◽  
Tensile Adhesion

The purpose of this study was to develop robust class II organic–inorganic films as antibacterial coatings on titanium alloy (Ti6Al4V) implants. Coating materials were prepared from organic chitosan (20–80 wt.%) coupled by 3-glycydoxytrimethoxysilane (GPTMS) with inorganic tetraethoxysilane (TEOS). These hybrid networks were imbedded with antimicrobial silver nanoparticles (AgNPs) and coated onto polished and acid-etched Ti6Al4V substrates. Magic-angle spinning nuclear magnetic resonance (13CMAS-NMR), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) and the ninhydrin assay, confirmed the presence and degree of covalent crosslinking (91%) between chitosan and GPTMS. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) identified surface roughness and microtopography on thin films and confirmed homogeneous distribution of elements throughout the coating. Cross-hatch and tensile adhesion testing demonstrated the robustness and adherence (15–20 MPa) of hybrid coatings to acid-etched titanium substrates. Staphylococcus aureus and Escherichia coli cultures and their biofilm formation were inhibited by all hybrid coatings. Antibacterial effects increased markedly for coatings loaded with AgNPs and appeared to increase with chitosan content in biofilm assays. These results are promising in the development of class II hybrid materials as robust and highly adherent antibacterial films on Ti6Al4V implants.

scholarly journals Iodoform-Blended Portland Cement for Dentistry

Prosthesis ◽  
2020 ◽  
Vol 2 (4) ◽  
pp. 277-296
Author(s):  
Qiu Li ◽  
Andrew D. Deacon ◽  
Nichola J. Coleman
Keyword(s):  
Portland Cement ◽  
Antimicrobial Properties ◽  
Antimicrobial Effect ◽  
Magic Angle Spinning ◽  
Cement Matrix ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Filling Materials ◽  
Human Osteosarcoma Cells ◽  
Angle Spinning

Portland cement-based formulations blended with radiopacifying agents are popular endodontic materials for various root filling and pulp capping applications. Iodoform (CHI3) is an alternative candidate radiopacifier whose impact on the setting, bioactivity, antimicrobial properties and cytotoxicity of white Portland cement were evaluated in this study. Isothermal conduction calorimetry and 29Si magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) showed that 20 wt% iodoform had no significant impact on the kinetics of cement hydration with respect to the formation of the major calcium silicate hydrate (C-S-H) gel product (throughout the 28-day observation). Conversely, transmission electron microscopy demonstrated that iodine was incorporated into the ettringite (Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O) product phase. Both iodoform-blended and pure Portland cements exhibited comparable biocompatibility with MG63 human osteosarcoma cells and similar bioactivity with respect to the formation of a hydroxyapatite layer upon immersion in simulated body fluid. By virtue of their high alkalinity, both cements inhibited the growth of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. However, in all cases, iodoform enhanced the antimicrobial effect and significantly reduced the minimum bactericidal concentration of the cement. In conclusion, iodoform offers antimicrobial advantages in Portland cement-based formulations where oral biofilm formation threatens the success of root filling materials and dentine substitutes. The reactivity with the calcium aluminosulfate components of the hydrating cement matrix warrants further research to understand the long-term stability of the cement matrix in the presence of iodoform.

Pulse Shaped Dynamic Nuclear Polarization Under Magic Angle Spinning

2019 ◽  
Author(s):  
ASIF EQUBAL ◽  
Kan Tagami ◽  
Songi Han
Keyword(s):  
Electron Spin ◽  
Lattice Relaxation ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Total Electron ◽  
Spin Lattice ◽  
Maximum Benefit ◽  
Selective Saturation ◽  
Angle Spinning

In this paper, we report on an entirely novel way of improving the MAS-DNP efficiency by shaped μw pulse train irradiation for fast and broad-banded (FAB) saturation of the electron spin resonance. FAB-DNP achieved with Arbitrary Wave Generated shaped μw pulse trains facilitates effective and selective saturation of a defined fraction of the total electron spins, and provides superior control over the DNP efficiency under MAS. Experimental and quantum-mechanics based numerically simulated results together demonstrate that FAB-DNP significantly outperforms CW-DNP when the EPR-line of PAs is broadened by conformational distribution and exchange coupling. We demonstrate that the maximum benefit of FAB DNP is achieved when the electron spin-lattice relaxation is fast relative to the MAS frequency, i.e. at higher temperatures and/or when employing metals as PAs. Calculations predict that under short T<sub>1e </sub>conditions AWG-DNP can achieve as much as ~4-fold greater enhancement compared to CW-DNP.

High Resolution Magic Angle Spinning NMR in Combinatorial Chemistry

2001 ◽  
Vol 4 (4) ◽  
pp. 333-351 ◽  
Author(s):  
G. Lippens ◽  
R. Warrass ◽  
J. Wieruszeski ◽  
P. Rousselot-Pailley ◽  
G. Chessari
Keyword(s):  
High Resolution ◽  
Combinatorial Chemistry ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Angle Spinning

Wideline 2H -NMR Spectroscopy and Imaging of Solids

1994 ◽  
Vol 49 (1-2) ◽  
pp. 19-26 ◽  
Author(s):  
B. Blümich
Keyword(s):  
Nmr Spectroscopy ◽  
Excitation Power ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
2H Nmr ◽  
Stochastic Excitation ◽  
2H Nmr Spectroscopy ◽  
Spatially Inhomogeneous ◽  
Recent Developments ◽  
Angle Spinning

Abstract Recent developments, focussing on reduction of the rf excitation power by stochastic excitation, on improvements in sensitivity and excitation bandwidth by magic angle spinning, and on combining wideline spectroscopy with spatial resolution for investigations o f spatially inhomogeneous objects are reviewed.

scholarly journals Preparation of Li3PS4–Li3PO4 Solid Electrolytes by Liquid-Phase Shaking for All-Solid-State Batteries

2021 ◽  
Vol 2 (1) ◽  
pp. 39-48
Author(s):  
Nguyen H. H. Phuc ◽  
Takaki Maeda ◽  
Tokoharu Yamamoto ◽  
Hiroyuki Muto ◽  
Atsunori Matsuda
Keyword(s):  
Solid Solution ◽  
Solid State ◽  
Liquid Phase ◽  
Room Temperature ◽  
Reaction Medium ◽  
Magic Angle Spinning ◽  
Resonance Spectroscopy ◽  
Synthesis Methods ◽  
Magic Angle ◽  
Angle Spinning

A solid solution of a 100Li3PS4·xLi3PO4 solid electrolyte was easily prepared by liquid-phase synthesis. Instead of the conventional solid-state synthesis methods, ethyl propionate was used as the reaction medium. The initial stage of the reaction among Li2S, P2S5 and Li3PO4 was proved by ultraviolet-visible spectroscopy. The powder X-ray diffraction (XRD) results showed that the solid solution was formed up to x = 6. At x = 20, XRD peaks of Li3PO4 were detected in the prepared sample after heat treatment at 170 °C. However, the samples obtained at room temperature showed no evidence of Li3PO4 remaining for x = 20. Solid phosphorus-31 magic angle spinning nuclear magnetic resonance spectroscopy results proved the formation of a POS33− unit in the sample with x = 6. Improvements of ionic conductivity at room temperature and activation energy were obtained with the formation of the solid solution. The sample with x = 6 exhibited a better stability against Li metal than that with x = 0. The all-solid-state half-cell employing the sample with x = 6 at the positive electrode exhibited a better charge–discharge capacity than that employing the sample with x = 0.

Magic Angle Spinning NMR Study on Inversion Behavior and Vacancy Disorder in Alumina-Rich Spinel

2018 ◽  
Vol 57 (14) ◽  
pp. 8390-8395 ◽  
Author(s):  
Bingtian Tu ◽  
He Zhang ◽  
Hao Wang ◽  
Weimin Wang ◽  
Zhengyi Fu
Keyword(s):  
Magic Angle Spinning ◽  
Magic Angle ◽  
Nmr Study ◽  
Angle Spinning
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