Diversifying i-motif-based pH sensors: Labeling patterns tune the intracellular localization
Scientists from IBCH together with the colleagues from Federal Research Center for Physical and Chemical Medicine developed an i-motif-based pH sensor. The authors synthesized a new non- fluorescent cytosine analogue, tC O Azo , which quenches the fluorescence of the known fluorescent cytosine mimic, tC O . Incorporation of the pair into a genomic iM-forming sequence C5T resulted in a high-contrast pH sensor with a working range compatible with physiological conditions. Unlike known C5T-based sensors, which contain conventional FAM/BHQ or FAM/TAMRA labels, provide a fluorescent signal in the green/red channels and accumulate in cell nuclei, the proposed sensor localized mainly in the cytoplasm and allowed pH monitoring based on the tC O signal in the blue channel. Thus, the authors managed to overcome the common problem of preferential accumulation in the nuclei of living cells for labeled nucleic acids (antisense oligonucleotides, molecular beacons, etc.). The work was published in Sensors and Actuators: B. Chemical.
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