Aptamer-engineered NIR-II Ru-doped carbon quantum dot nanozyme for photoacoustic imaging-guided synergistic photothermal and catalytic cancer therapy

Carbon quantum dot (CQD)-based nanozymes have attracted growing interest for advanced biomedical applications owing to their superior catalytic activity, photostability, and biocompatibility. However, the rational design of a multifunctional nanoplatform that integrates active targeting, multimodal imaging, and synergistic therapy through a green and sustainable approach remains highly challenging. Herein, we report a facile and environmentally benign solvothermal strategy for the synthesis of ruthenium-doped CQD nanozymes (Ru-CQDs) functionalized with AS1411 aptamers and polyethylene glycol (PEG), denoted as Ru-CQDs-AS1411@PEG. This eco-friendly synthesis avoids toxic reagents and harsh conditions while yielding highly uniform and biocompatible nanozymes. The obtained Ru-CQDs-AS1411@PEG exhibit strong NIR-II absorption, high photothermal conversion efficiency, and pronounced peroxidase-mimicking catalytic activity. The AS1411 aptamer confers active tumor-targeting capability, while PEGylation enhances aqueous dispersibility and physiological stability. Both in vitro and in vivo studies demonstrate that Ru-CQDs-AS1411@PEG enable precise photoacoustic tumor imaging and potent tumor ablation under NIR-II laser irradiation via synergistic photothermal and catalytic reactive oxygen species (ROS) generation. This work provides a green-engineered, aptamer-guided CQD nanozyme platform with integrated targeting, imaging, and therapeutic functionalities, offering a promising and sustainable approach for precision cancer theranostics.