A phosphonated triarylmethyl radical as a probe for measurement of pH by EPR

Driesschaert, Benoît; Marchand, Valérie; Lévêque, Philippe; Gallez, Bernard; Marchand‐Brynaert, Jacqueline

doi:10.1039/c2cc00025c

Cited by 43 publications

(54 citation statements)

References 13 publications

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“…TAMs have advantages over nitroxides in extraordinary stability toward tissue redox processes, longer relaxation time and narrower line width making them particularly attractive for imaging applications. Applications of TAM radicals as functional probes include EPR oximetry (ArdenkjaerLarsen et al, 1998;Golman et al, 2000;Krishna et al, 2002) and recently reported sensitivity to the superoxide anion Kutala et al, 2008) and pH (Bobko et al, 2007a;Dhimitruka et al, 2008;Driesschaert et al, 2012). On the other hand NRs have tremendous advantage over TAMs in well-developed chemistry.…”

Section: Resultsmentioning

confidence: 99%

In vivo Spectroscopy and Imaging of Nitroxide Probes

Khramtsov¹

2012

Nitroxides - Theory, Experiment and Applications

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Section: Resultsmentioning

confidence: 99%

In vivo Spectroscopy and Imaging of Nitroxide Probes

Khramtsov¹

2012

Nitroxides - Theory, Experiment and Applications

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“…Trityl radicals have not only been employed in EPR oximetry, 14,27,28 but also in many other applications, e.g., specific detection of superoxide radical anions, [29][30][31] pH measurements, 32,33 as well as analysis of redox status. 34 Trityl-based spin labels were used for distance measurements, e.g., in nucleic acids.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Nanoencapsulation of Tetrathiatriarylmethyl and Tetrachlorotriarylmethyl (Trityl) Radical Derivatives—A Study To Advance Their Applicability as in Vivo EPR Oxygen Sensors

et al. 2015

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Tissue oxygenation plays an important role in the pathophysiology of various diseases and is often a marker of prognosis and therapeutic response. EPR (ESR) is a suitable noninvasive oximetry technique. However, to reliably deploy soluble EPR probes as oxygen sensors in complex biological systems, there is still a need to investigate and improve their specificity, sensitivity, and stability. We reproducibly synthesized various derivatives of tetrathiatriarylmethyl and tetrachlorotriarylmethyl (trityl) radicals. Hydrophilic radicals were investigated in aqueous solution mimicking physiological conditions by, e.g., variation of viscosity and ionic strength. Their specificity was satisfactory, but the oxygen sensitivity was low. To enhance the capability of trityl radicals as oxygen sensors, encapsulation into oily core nanocapsules was performed. Thus, different lipophilic triesters were prepared and characterized in oily solution employing oils typically used in drug formulations, i.e., middle-chain triglycerides and isopropyl myristate. Our screening identified the deuterated ethyl ester of D-TAM (radical 13) to be suitable. It had an extremely narrow single EPR line under anoxic conditions and excellent oxygen sensitivity. After encapsulation, it retained its oxygen responsiveness and was protected against reduction by ascorbic acid. These biocompatible and highly sensitive nanosensors offer great potential for future EPR oximetry applications in preclinical research.

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“…Persistent triarylmethyl radicals [1] (trityls, TAMs, see Figure 1) have recently been proposed as ideal spin probes for numerous applications in biology, [2–5] analytical chemistry, [6] and materials science. [7] Trityls are stable towards the majority of biological oxidants and reductants.…”

Section: Introductionmentioning

confidence: 99%