Ultrasensitive upconverting nanoprobes for in situ imaging of drug-induced liver injury using miR-122 as the biomarker.

Drug-induced liver injury (DILI) is a frequent adverse drug reaction. The current clinical diagnostic methods are inadequate for accurate and early detection of DILI due to the lack of effective diagnostic biomarkers. Hepatocyte-specific miR-122 is released from injured hepatocytes promptly and its efflux is significantly correlated with the progression of DILI. Therefore, achieving precise in situ detection of miR-122 with high sensitivity is vital for early visualization of DILI. Herein, a new nanoprobe, consisting of miR-122 aptamer, upconversion nanoparticles (UCNPs) and Prussian blue nanoparticles (PBNPs) was introduced for the early and sensitive detection of DILI in situ. As the nanoprobes reached in the liver, miR-122 aptamer-based entropy-driven strand displacement (ESDR) signal amplification reaction was triggered and luminescence resonance energy transfer (LRET) between UCNPs and PBNPs was responded to achieve the high-fidelity detection of DILI. A negative correlation was observed between the intensity of upconversion luminescence (UCL) and the concentration of miR-122. UCL imaging conducted both in vivo and ex vivo indicated that a reduction in miR-122 concentration led to an increase in UCL intensity, revealing a precise state of DILI. The detection technique demonstrated a positive correlation between signal intensity and severity, offering a more straightforward and intuitive method of visualizing DILI.