Real-time monitoring and accurate diagnosis of drug-induced hepatotoxicity in vivo by ratio-fluorescence and photoacoustic imaging of peroxynitrite†
Because of the low tissue penetration depth and poor photostability of organic cyanine dye, in addition to environmental interference, it is a great challenge to monitor the degree of drug-induced hepatotoxicity by the in vivo detection of peroxynitrite (ONOO−). Herein, we fabricated heptamethine cyanine dye (P-cy7)-coordinated upconversion nanoparticles (UCNPs), namely UCY7, as a fluorescent nanoprobe for evaluating drug-induced hepatotoxicity. Due to the luminescence resonance energy transfer (LRET) between UCNPs and the cyanine dye (P-cy7), the irradiation changed from visible light at 660 nm to near infrared (NIR) light at 980 nm; therefore, the issues of poor photostability and severe photobleaching of cyanine dye can be effectively solved. After injecting via the tail vein, the nanoprobes are rapidly concentrated in the liver. Since the level of ONOO− is up-regulated during the drug-induced liver injury, the LRET between UCNPs and P-cy7 is disrupted to release the upconversion luminescence at 656 nm, while the upconversion luminescence at 800 nm remains constant, thus achieving the ratio-fluorescent imaging (RFLI) of ONOO− in the liver to calibrate the influence of the environment. In addition, the reduction in the absorption of nanoprobes in the presence of ONOO− allows for sensitive photoacoustic imaging (PAI). Based on the RFLI and PAI of the liver, the real-time monitoring and accurate diagnosis of different degrees of hepatotoxicity using the model of Acetaminophen (APAP) induction was achieved successfully, providing a new approach for the clinical evaluation of drug-induced hepatotoxicity.