Bright NIR-II fluorescence lipid membrane probes for labelling of biomimetic nanovesicles with image-guided targeted NIR-II mild photothermal-immunotherapy of orthotopic glioblastoma.

Cell-derived nanovesicles possess the capacity to cross the blood-brain barrier (BBB) and modulate the immunosuppressive tumor microenvironment (TME); however, the lack of efficient labelling probes limits their application in tracing biodistribution and achieving synergistic glioblastoma (GBM) theranostics. Herein, we report bright NIR-II fluorescence membrane probe (CL1)-labelled nanovesicles (CL1-L-TV) composed of liposomes (L) and activated autologous T cell-derived extracellular vesicles (TV) for image-guided NIR-II mild photothermal immunotherapy of GBM. Through lipid conjugation, CL1 intercalates deeply into the L-TV bilayer, physically avoiding aggregation-caused quenching (ACQ) and achieving substantially enhanced NIR-II fluorescence quantum yield (QY = 5.98%), as confirmed by simulations, along with a high photothermal conversion efficiency (PCE = 69.1%). The overexpressed T cell receptors and PD-1 on the TV surface mediate interactions with major histocompatibility complex (MHC) and PD-L1 on GBM cells, respectively, effectively facilitating BBB crossing, GBM targeting, and immune checkpoint blockade (ICB). Furthermore, CL1-L-TV enables imaging to precisely localize GBM, reports the tumoral molecular microenvironment, mediates photothermal immunotherapy to ablate primary tumors locally, induces immunogenic cell death, releases tumor damage-associated antigens, promotes dendritic cell (DC) maturation, reinvigorates cytotoxic T lymphocyte infiltration, and elicits abscopal antitumor effects, as validated by gene expression analyses. This study highlights the potential of NIR-II fluorescent lipid probes for nanovesicle labelling and image-guided photothermal-immunotherapy.