Year: 2008
Type: article
Abstract: This issue of the Israel Journal of Chemistry is dedicated to the field of electron spin resonance imaging (ESRI). While historically ESR preceded nuclear magnetic resonance (NMR), it has always been “deprived”, with respect to its “big brother”, NMR. This is probably due to the fact that spectroscopic NMR, and, especially clinical NMR imaging (MRI), is carried out mostly with native compounds (for example, water), without the need to introduce “foreign materials” such as stable radicals into the system for ESR studies. In addition, ESR is far more technologically challenging than NMR due to the use of a much higher energy source (microwave frequencies) and the necessity to work with much shorter relaxation times. Faced by these fundamental handicaps, ESR, despite its uniqueness for the direct detection of free radicals and paramagnetic species, has not advanced to the level of sophistication and popularity in the world of magnetic resonance. Our intention in this special issue was to increase the awareness to the tremendous advance in the field of ESR imaging and to show how the ESR imaging and related technologies can serve as a complementary method to NMR imaging. For example, as described in this issue by the paper of Vikram et al., ESR imaging can provide accurate quantitative information regarding partial pressure of molecular oxygen (pO2) distribution in tissue and cells. This is achieved by monitoring the ESR relaxation time variations due to the presence of the paramagnetic oxygen molecule. Furthermore, as shown in an article by Kulkarni et al., the reduction rate of paramagnetic probes can serve as a qualitative means to measure the redox state of tissues. Although in most cases ESR requires the addition of stable paramagnetic molecules to the sample, this is not always the case, as presented in the contribution by Levěque et al., which shows applications of ESR imaging carried out with native paramagnetic substances to characterize a variety of foodstuffs. The high sensitivity per spin of ESR can be used to greatly increase the resolution of ESR imaging well beyond that of conventional NMR. This feature is exemplified by the papers of Dormann et al. and Suhovoy and Blank. The first paper reviews the capability of ESR to image organic conductors down to 10-micron resolution, while the second shows how high-resolution ESR imaging might be employed in the field of quantum computing. High-resolution ESR imaging can also be obtained by scanning of a miniature microwave probe over a surface of interest, as described by Sakran et al. Such a probe can also be employed in conjunction with local optical imaging. Finally, the manuscript by Savla et al. discusses the possibility of employing the unique magnetic microscopy detection method to greatly enhance sensitivity and resolution over conventional magnetic resonance-based detection schemes. These contributions represent only a small fraction of the work carried out and the applications pursued in the field of ESR imaging worldwide. We hope that this special issue will serve as a good “reference” point for the reader by both underlining the new trends and achievements in the field and possibly triggering the development of new applications.
Source: Israel Journal of Chemistry
DOI: 10.1560/ijc.48.1.i
Authors: Periannan Kuppusamy, Aharon Blank
Language: English
Subfield: Biophysics
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2001748846