Microfluidic Assembly of NIR‐II AIE Nanoparticles for Enhanced Photothermal Ablation of Breast Tumors

Aggregation-induced emission (AIE) luminogens with strong near-infrared absorption and excellent photostability are emerging as powerful photothermal agents; however, achieving nanoscale formulations with controlled size, high stability, and near-infrared-II (NIR-II) emission remains challenging. Here, we report an NIR-II emissive AIE small molecule that can be rapidly assembled into monodisperse nanoparticles (NDA-MEPA NPs, ∼40 nm) using a microfluidic strategy that ensures reproducible control over particle size and uniformity. Surface encapsulation with DSPE-PEG2K confers excellent colloidal stability, biocompatibility, and enhanced tumor accumulation. The resulting NDA-MEPA NPs exhibit efficient photothermal conversion under 808 nm irradiation, along with dose- and time-dependent cellular uptake, and induce robust photothermal cytotoxicity in vitro. In vivo evaluations demonstrated that NDA-MEPA NPs enable high-contrast NIR-II fluorescence imaging and effective photothermal tumor ablation with minimal systemic toxicity. This work establishes a programmable microfluidic approach for constructing NIR-II AIE nanomaterials and highlights a biocompatible photothermal platform with strong potential for translational cancer therapy.