The development of efficient contrast agents for tumor-targeted imaging remains a critical challenge in the clinic. Herein, we proposed a tumor-derived extracellular vesicle (EV)-mediated targeting approach to improve in vivo tumor imaging using ternary downconversion nanoparticles (DCNPs) with strong near infrared II (NIR-II) luminescence at 1,525 nm. The EVs were metabolically engineered with azide group, followed by in vivo labeling of DCNPs through copper-free click chemistry. By taking advantage of the homologous targeting property of tumor derived EVs, remarkable improvement in the tumor accumulation (6.5% injection dose (ID)/g) was achieved in the subcutaneous colorectal cancer model when compared to that of individual DCNPs via passive targeting (1.1% ID/g). Importantly, such bioorthogonal labeling significantly increased NIR-II luminescence signals and prolonged the retention at tumor sites. Our work demonstrates the great potential of EVs-mediated bioorthogonal approach for in vivo labeling of NIR-II optical probes, which provides a robust tool for tumor-specific imaging and targeted therapy.

Abnormal metabolism has become a potential target for highly malignant and invasive triple-negative breast cancer (TNBC) due to its relatively low response to traditional therapeutics. The existing metabolic interventions demonstrated unsatisfactory therapeutic outcomes and potential systemic toxicity, resulting from the metabolic instability and limited targeting ability of inhibitors as well as complex tumor microenvironment. To address these limitations, here we developed a robust pyroelectric BaTiO₃@Au core–shell nanostructure (BTO@Au) to selectively and persistently block energy generation of tumor cells. Stimulated by near-infrared (NIR) laser, the Au shell could generate heat to activate the BaTiO₃ core to produce reactive oxygen species (ROS) regardless of the constrained microenvironment, thus prominently inhibits mitochondrial oxidative phosphorylation (OXPHOS) and reduces ATP production to induce TNBC cell apoptosis. The therapeutic effects have been well demonstrated in vitro and in vivo, paving a new way for the development of metabolic interventions.