Practical Aspects in the Study of Biological Photosensitization Including Reaction Mechanisms and Product Analyses: A Do's and Don'ts Guide. (30th January 2023)

• Record Type: Journal Article
• Authors: Baptista, Maurício S.; Cadet, Jean; Greer, Alexander; Thomas, Andrés H.
• Is Part Of: Photochemistry and photobiology. Volume 99:Number 2(2023)
• Page Start: 313
• Page End: 334
• Publication Date: 2023-01-30
• Subjects: Photochemistry -- Periodicals; Light -- Physiological effect -- Periodicals; 541.35
• DOI: 10.1111/php.13774
• Languages: English
• ISSNs: 0031-8655

Abstract

Abstract: The interaction of light with natural matter leads to a plethora of photosensitized reactions. These reactions cause the degradation of biomolecules, such as DNA, lipids, proteins, being therefore detrimental to the living organisms, or they can also be beneficial by allowing the treatment of several diseases by photomedicine. Based on the molecular mechanistic understanding of the photosensitization reactions, we propose to classify them in four processes: oxygen‐dependent (type I and type II processes) and oxygen‐ in dependent [triplet‐triplet energy transfer (TTET) and photoadduct formation]. In here, these processes are discussed by considering a wide variety of approaches including time‐resolved and steady‐state techniques, together with solvent, quencher, and scavenger effects. The main aim of this survey is to provide a description of general techniques and approaches that can be used to investigate photosensitization reactions of biomolecules together with basic recommendations on good practices. Illustration of the suitability of these approaches is provided by the measurement of key biomarkers of singlet oxygen and one‐electron oxidation reactions in both isolated and cellular DNA. Our work is an educational review that is mostly addressed to students and beginners. Abstract : With the main goal of facilitating the understanding of photosensitized reactions, efforts were made to critically survey the main experimental approaches that were developed for this purpose. Time‐resolved and steady‐state spectroscopic methods as well as the role of additives and quenchers are discussed, thus highlighting their potential and limitations. We hope that the reported study, essentially educational, will provide good standard practices, with clear hints on how to gain mechanistic insights into photosensitized oxidation reactions.