双模态成像实现原位胶质瘤中脑室内 CAR-T 疗法的纵向生物分布分析

Locoregional CAR-T delivery is increasingly explored for glioblastoma to improve intracranial tumor exposure; however, organ-level biodistribution kinetics after intracranial administration remain poorly quantified in vivo, limiting route-informed optimization and preclinical risk assessment.

Here, we report a dual-modality cell labeling and tracking strategy based on indocyanine green-conjugated iron nanoparticles (ICG-NPs) for in vivo assessment of B7-H3-targeting CAR-T cell (TX103) biodistribution using second near-infrared window (NIR-II) fluorescence imaging and magnetic resonance imaging (MRI). Using a heparin-protamine-assisted protocol, TX103 cells were labeled with high efficiency (83. 1%) without detectable changes in viability, CAR expression, immunophenotype (including activation/exhaustion marker profile and CXCR3 expression), or cytotoxic function.

In vitro imaging demonstrated a linear correlation between NIR-II fluorescence intensity and labeled cell numbers (R 2 = 0. 973, p < 0. 001), while MRI provided complementary anatomical context at higher cell densities. In an orthotopic glioma mouse model, longitudinal MRI and NIR-II imaging captured route-dependent differences in tumor-associated localization and whole-body biodistribution following intracerebroventricular and intravenous administration.

Furthermore, organ-level NIR-II exposure showed a positive association with CD3 T-cell density across organs (R 2 = 0. 552, p < 0. 001), supported by multi-organ pathological validation. Collectively, we establish a biocompatible dual-modality workflow that links intracranial anatomical localization with longitudinal whole-body biodistribution readouts for preclinical CAR-T tracking in solid tumor models.