Photodynamic therapy involves the excitation of a non-toxic dye by harmless visible light to produce a long-lived triplet state that can interact with molecular oxygen to produce reactive oxygen species (ROS), which can damage biomolecules and kill cells. ROS produced by electron transfer (Type 1) include superoxide, hydrogen peroxide and hydroxyl radical (HO), while singlet oxygen (O) is produced by energy transfer. Diverse methods exist to distinguish between these two pathways, some of which are more specific or more sensitive than others. In this review we cover the use of two fluorescence probes: singlet oxygen sensor green (SOSG) detects O; and 4-hydroxyphenyl-fluorescein (HPF) that detects HO. Interesting data was collected concerning the photochemical pathways of functionalized fullerenes compared to tetrapyrroles, stable synthetic bacteriochlorins with and without central metals, phenothiazinium dyes interacting with inorganic salts such as azide.
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http://dx.doi.org/10.1016/j.ymeth.2016.06.025 | DOI Listing |
Environ Sci Technol
December 2024
State Ecology and Environment Scientific Observation and Research Station for the Yangtze River Delta at Dianshan Lake, Shanghai Environmental Monitoring Center, Shanghai 200030, China.
Biomass burning is an important source of brown carbon (BrC) aerosols, which influence climate by affecting the Earth's radiative balance. However, the transformation pathways of BrC chromophores, especially in the presence of photochemically active species, such as nitrate, are not well understood. In this study, the nitrate-mediated aqueous-phase photooxidation of three typical BrC chromophores from biomass burning was investigated, including 4-nitrocatechol, 3-nitrosalicylic acid, and 3,4-dinitrophenol.
View Article and Find Full Text PDFACS Earth Space Chem
December 2024
NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, United States.
Laboratory investigations of photochemical reactions in simulated Titan-like atmospheric systems provide insight into the formation of gas and aerosol products and the influence of different environmental parameters on the types of organic molecules generated. Studying the gas-phase products as a function of reaction time provides further insight into the reaction pathways that lead to organic production. The stable isotopes in the reactants and products serve as tracers and help to disentangle these reaction pathways.
View Article and Find Full Text PDFChem Sci
December 2024
Organic Chemistry Division, CSIR-National Chemical Laboratory (CSIR-NCL) Pune 411 008 India
The isoquinoline core is present in one of the largest subsets of bioactive natural products. The multifunctional isoquinoline core exerts diverse bioactivity, resulting in the development of numerous isoquinoline-based drugs and molecules that are currently under clinical trials. We developed a new approach for phosphite-mediated [1,2] alkyl migration for an overall -C-H alkylation -alkylation of isoquinoline.
View Article and Find Full Text PDFBeilstein J Org Chem
December 2024
Department of Chemical and Geological Sciences, University of Cagliari, S.S. 554, bivio per Sestu, 09042 Monserrato (CA), Italy.
The rising popularity of bioconjugate therapeutics has led to growing interest in late-stage functionalization (LSF) of peptide scaffolds. α,β-Unsaturated amino acids like dehydroalanine (Dha) derivatives have emerged as particularly useful structures, as the electron-deficient olefin moiety can engage in late-stage functionalization reactions, like a Giese-type reaction. Cheap and widely available building blocks like organohalides can be converted into alkyl radicals by means of photoinduced silane-mediated halogen-atom transfer (XAT) to offer a mild and straightforward methodology of alkylation.
View Article and Find Full Text PDFBiochemistry
December 2024
Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
Large Stokes shift red fluorescent proteins (LSS-RFPs) are of growing interest for multicolor bioimaging applications. However, their photochemical mechanisms are not fully understood. Here, we employed the QM(XDW-CASPT2//CASSCF)/MM method to investigate the excited-state proton transfer and photoisomerization processes of the LSS-RFP mKeima starting from its cis neutral isomer.
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