| 研究実績の概要 |
We synthesized “oxidative stress” sensor (OxiStressSens) based on conjugation of quantum dots with multi-nitroxide-functionalized cyclodextrin. The oxidation of nitroxide residues to their radical form was accompanied by strong quenching of quantum dot fluorescence and appearance of high EPR contrast. In opposite, the reduction of nitroxide residues in their hydroxylamine form was accompanied by rapid decay of EPR signal and appearance of strong fluorescence signal. Thus, OxyStressSens allows evaluation of the balance between reducers/oxidizers and level of “oxidative stress”.
The sensor enters into viable cells, which was visualized by EPR and fluorescent imaging. OxyStressSens was applied for detection of “oxidative stress” in cell suspensions, treated by rotenone and 2-methoxyestradiol; a combination, inducing mitochondrial dysfunction, overproduction of superoxide and mild or severe oxidative damages, as well as on cell with different proliferation index. The physicochemical characteristics and easy cell permeability give a reason to believe that the sensor will be appropriate for in vivo imaging. Since the T1-weigheted MRI contrast of nitroxides follows the same dynamics as their EPR contrast, the sensor is applicable also for nitroxide-enhanced MRI studies.
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