Bandgap-Engineered PtxTey:Ag2Te Composite Quantum Dots Enable Programmable NIR-II Imaging and Photothermal-Immune Synergistic Therapy.

Real-time monitoring of tumor spatiotemporal dynamics and precise modulation of the tumor immune microenvironment are pivotal for effective cancer treatment. However, current platforms lack the ability to integrate quantitative molecular imaging with spatially confined immune modulation. Here, we report a nanotheranostic platform Pt2Te3:Ag2Te-αPD-L1 (PAPD) based on bandgap-engineered PtxTey:Ag2Te quantum dots. Platinum-induced electronic reconfiguration enables programmable bandgap modulation, yielding tunable near-infrared IIb emission spanning from 1550 to 2200 nm. Pt2Te3:Ag2Te quantum dots exhibit stable emission at 1730 nm and controllable mild photothermal effects. Conjugation with αPD-L1 antibodies endows the PAPD platform with dual tumor-targeting capability through EPR-mediated passive accumulation and PD-L1-specific active recognition. Crucially, near-infrared IIb molecular imaging enables quantitative monitoring of tumor targeting and therapeutic response, meanwhile mild photothermal modulation induces immune reprogramming that sensitizes tumors to immune checkpoint immunotherapy in vivo. This work establishes a generalizable quantum-engineered nanotheranostic platform, offering a scalable strategy for precision cancer treatment.