Electron spin resonance (ESR)-spectroscopy

Anti-Pollution Matrix > Methods > Method list
> Electron spin resonance (ESR)-spectroscopy

Method

Studies have shown that the mechanism of skin damage caused by air pollution is mainly based on the generation of free radicals.

Electron spin resonance (ESR) spectroscopy represents a non-invasive method for the detection of radical formation in tissues (in vivo, ex vivo)[1-5] and cell cultures. Free radicals can be quantified and characterized by this method [3].

The use of so-called spin markers allows statements to be made about the radical formation or the endogenous redox state. Nitroxides are mostly used for spin markers. Nitroxides are paramagnetic species that have a free, unpaired electron in their outer shell. This property leads them to provide a characteristic ESR signal on their own, i.e. they are ESR active. After reaction with a radical, they become ESR inactive, i.e., the intensity of the signal decreases with increasing radical production. To study radical generation induced by exogenous factors, such as irradiation, cigarette smoke, the spin marker PCA (3-(carboxyl)-2,2,5,5-tetramethyl-1-pyrrolidinyloxy) can be used. From the intensity decrease of the PCA signal over the measured time, quantification of formed radicals in the skin is possible [2-6].

The nitroxide 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) represents a typical spin marker for the study of antioxidant status. Its amphiphilic character allows uptake into cells, allowing this spin marker to interact directly with metabolically produced radicals and antioxidants. A decrease in the ESR signal of TEMPO over time, allows conclusions to be drawn about redox status [1].

So-called "spin traps"  are used to determine radical types. The spin trap DMPO (5,5-dimethyl-1-pyrroline-N-oxide) can be used to distinguish between reactive oxygen species (ROS) and lipid oxygen species (LOS) in skin. With spin traps, in contrast to spin markers, no ESR signal is initially visible. Only after reaction with a radical is a signal apparent that can be characterized by simulation.  Spin traps are currently only applicable ex vivo and in vitro [3].

 

Detection of

• free radicals
• Investigation of the antioxidative status in skin/cells
• radical types; differentiation between ROS and LOS

 

Suitable for

• Examination of skin that has experienced exposure to e.g. pollution, solar radiation (UV, VIS, NIR) [4, 5]. Testing of efficacy against increased radical production of anti-pollution products compared to untreated skin and other cream formulations.
• Comparison of systemic and topical application of active ingredients on the antioxidant status of the skin.

 

References

[1] Lohan SB, Lauer AC, Arndt S, Friedrich A, Tscherch K, Haag SF, Darvin ME, Vollert H, Kleemann A, Gersonde I, Groth N, Lademann J, Rohn S, Meinke MC: Determination of the antioxidant status of the skin by in vivo-electron paramagnetic resonance (epr) spectroscopy. Cosmetics (2015), 2:286-301. https://doi.org/10.3390/cosmetics2030286
[2] Lohan SB, Muller R, Albrecht S, Mink K, Tscherch K, Ismaeel F, Lademann J, Rohn S, Meinke MC: Free radicals induced by sunlight in different spectral regions - in vivo versus ex vivo study. Exp Dermatol (2016), 25:380-385. DOI: 10.1111/exd.12987
[3] Albrecht S, Elpelt A, Kasim C, Reble C, Mundhenk L, Pischon H, Hedtrich S, Witzel C, Lademann J, Zastrow L, Beckers I, Meinke MC: Quantification and characterization of radical production in human, animal and 3D skin models during sun irradiation measured by epr spectroscopy. Free Radic Biol Med (2019), 131:299-308. DOI: 10.1016/j.freeradbiomed.2018.12.022
[4] Albrecht S, Jung S, Muller R, Lademann J, Zuberbier T, Zastrow L, Reble C, Beckers I, Meinke MC: Skin type differences in solar-simulated radiation-induced oxidative stress. Br J Dermatol (2019), 180:597-603. DOI: 10.1111/bjd.17129
[5] S.B. Lohan, K. Buhring, A.C. Lauer, A. Friedrich, J. Lademann, A. Buss, R. Sabat, K. Wolk, M.C. Meinke, Analysis of the Status of the Cutaneous Endogenous and Exogenous Antioxidative System of Smokers and the Short-Term Effect of Defined Smoking Thereon, Antioxidants (Basel), 9 (2020). DOI: 10.3390/antiox9060537
[6] Bielfeldt, S., Jung, K., Laing, S., Moga, A., & Wilhelm, K. P. Anti‐pollution effects of two antioxidants and a chelator—Ex vivo electron spin resonance and in vivo cigarette smoke model assessments in human skin. Skin Research and Technology (2021) https://doi.org/10.1111/srt.13068

ESR in general and application:
EPR Spectroscopy: Applications in Chemistry and Biology (Topics in Current Chemistry (Band 321), Hrsg. Malte Drescher, Gunnar Jeschke,  ISBN-13 : 978-3642283468