ABSTRACT

British polymath Joseph Priestley developed the nitrous air test to monitor the quality of air, where he used Nitric Oxide (NO) as a probe, and it is believed to be the major pollutant of air. Presently, a significant amount of NO present in air is produced by different chemical plants. At low concentration, NO regulates long-term potentiation of the brain and vasodilation, while high concentration leads to the formation of reactive nitrogen species, which, in turn, causes carcinogenesis and neurodegenerative disorders. NO, being a free-radical species, diffuses spontaneously through cells and tissues and reacts with most biological targets; hence real-time monitoring of NO is a potential challenge, and real-time detection of NO released from living cells is a new avenue of biological research and drug discovery. Common spectroscopic techniques such as UV-visible, electron spin resonance, and fluorescence spectroscopy have also been used for the detection of NO.