Nitrogen nuclear spin flips in nitroxide spin probes of different sizes in glassy o-terphenyl: Possible relation with α- and β-relaxations

2011 ◽  
Vol 135 (9) ◽  
pp. 094508 ◽  
Author(s):  
N. P. Isaev ◽  
S. A. Dzuba
Keyword(s):  
Nuclear Spin ◽  
Spin Probes ◽  
Nitroxide Spin Probes ◽  
Spin Flips

Line broadening in the electron resonance spectra of spin probes dissolved in anisotropic media: the effect of nuclear spin quantization

1977 ◽  
Vol 353 (1672) ◽  
pp. 87-102 ◽  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nuclear Spin ◽  
Dynamic Properties ◽  
Orientational Order ◽  
Anisotropic Media ◽  
Approximate Theory ◽  
Spin Probes ◽  
Line Broadening ◽  
Electron Resonance

The line broadening in the electron resonance spectra of monoradicals dissolved in anisotropic media, such as liquid crystals, provides a valuable probe of both the orientational order and the molecular dynamics. However, the fast-motion relaxation theory employed to extract this information from the linewidths assumes that the nuclear spin is quantized along the direction of the magnetic field. This approximation is only correct when the symmetry axis of a uniaxial liquid crystal is either parallel or perpendicular to the field. We have therefore removed this assumption and have developed a general theory of line broadening valid for all orientations of the liquid crystal. The theory is then used to evaluate the angular dependence of the linewidths and this is compared with the dependence predicted by the approximate theory, for two classes of nitroxide spin probes. These comparisons reveal that for steroidal spin probes the error, introduced by assuming the nuclear spin to be quantized along the field, is confined to the dynamic properties derived from the linewidths. In contrast, significant errors appear in both the dynamic and static properties obtained from an analysis of the linewidth variations for fatty acid spin probes based on the approximate theory. It would seem that the exact theory must be employed to obtain precise information from linewidth investigations of liquid crystals, except when the orientational order is extremely small.

Aβ(25–35) peptide displays H2O2-like reactivity towards aqueous FE2+, nitroxide spin probes, Ant) synaptosomal membrane proteins

Life Sciences ◽  
1995 ◽  
Vol 58 (3) ◽  
pp. 217-228 ◽  
Author(s):  
D.Allan Butterfield ◽  
Laura Martin ◽  
John M. Carney ◽  
Kenneth Hensley
Keyword(s):  
Membrane Proteins ◽  
Spin Probes ◽  
Synaptosomal Membrane ◽  
Nitroxide Spin Probes

scholarly journals Doxyl Nitroxide Spin Probes Can Modify Toxicity of Doxorubicin towards Fibroblast Cells

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5138
Author(s):  
Jan Czepas ◽  
Karolina Matczak ◽  
Aneta Koceva-Chyła ◽  
Bartłomiej Grobelski ◽  
Zofia Jóźwiak ◽  
...  
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Membrane Fluidity ◽  
Biological Properties ◽  
Spin Probes ◽  
Trypan Blue Exclusion ◽  
Paramagnetic Resonance ◽  
Trypan Blue Exclusion Test ◽  
High Concentrations ◽  
Nitroxide Spin Probes

The biological properties of doxyl stearate nitroxides (DSs): 5-DS, Met-12-DS, and 16-DS, commonly used as spin probes, have not been explored in much detail so far. Furthermore, the influence of DSs on the cellular changes induced by the anticancer drug doxorubicin (DOX) has not yet been investigated. Therefore, we examined the cytotoxicity of DSs and their ability to induce cell death and to influence on fluidity and lipid peroxidation (LPO) in the plasma membrane of immortalised B14 fibroblasts, used as a model neoplastic cells, susceptible to DOX-induced changes. The influence of DSs on DOX toxicity was also investigated and compared with that of a natural reference antioxidant α-Tocopherol. By employing the trypan blue exclusion test and double fluorescent staining, we found a significant level of cytotoxicity for DSs and showed that their ability to induce apoptosis and modify plasma membrane fluidity (measured fluorimetrically) is more potent than for α-Tocopherol. The most cytotoxic nitroxide was 5-DS. The electron paramagnetic resonance (EPR) measurements revealed that 5-DS was reduced in B14 cells at the fastest and Met-12-DS at the slowest rate. In the presence of DOX, DSs were reduced slower than alone. The investigated compounds, administered with DOX, enhanced DOX-induced cell death and demonstrated concentration-dependent biphasic influence on membrane fluidity. A-Tocopherol showed weaker effects than DSs, regardless the mode of its application—alone or with DOX. High concentrations of α-Tocopherol and DSs decreased DOX-induced LPO. Substantial cytotoxicity of the DSs suggests that they should be used more carefully in the investigations performed on sensitive cells. Enhancement of DOX toxicity by DSs showed their potential to act as chemosensitizers of cancer cells to anthracycline chemotherapy.

Rotational and Translational Mobility of Nitroxide Spin Probes in Ionic Liquids and Molecular Solvents

2010 ◽  
Vol 39 (4) ◽  
pp. 409-421 ◽  
Author(s):  
N. A. Chumakova ◽  
V. I. Pergushov ◽  
A. Kh. Vorobiev ◽  
A. I. Kokorin
Keyword(s):  
Ionic Liquids ◽  
Spin Probes ◽  
Translational Mobility ◽  
Nitroxide Spin Probes ◽  
Molecular Solvents

Inherent Microporosity and Photostability of Fluoroacrylic Polymer Films Studied by Electron Paramagnetic Resonance of Nitroxide Spin Probes

2015 ◽  
Vol 46 (5) ◽  
pp. 523-540 ◽  
Author(s):  
A. M. Sheveleva ◽  
I. K. Shundrina ◽  
S. L. Veber ◽  
A. D. Buhtojarova ◽  
V. V. Russkih ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Polymer Films ◽  
Spin Probes ◽  
Paramagnetic Resonance ◽  
Nitroxide Spin Probes ◽  
Electron Paramagnetic
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